Embed Size (px)
Citation preview
Enteral Nutrition
Maanit Kohli, Allen Andrade, and T. S. Dharmarajan
ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Diagnostic Criteria for Malnutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pathophysiology of Malnutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Methods of Nutritional Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Oral Nutritional Supplements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Enteral Nutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Enteral Formulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Standard Polymeric Formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Fiber Containing Formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Predigested . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Blenderized Formulas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Disease-Specific Formulas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Diabetes Mellitus (Type 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Hepatic Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Chronic Kidney Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
M. Kohli (*)Division of Hospital Medicine, Department of Medicine,Icahn School of Medicine at Mount Sinai, New York, NY,USAe-mail: [email protected]
A. AndradeBrookdale Department of Geriatrics and Palliative Care,Icahn School of Medicine at Mount Sinai, New York, NY,USAe-mail: [email protected]
T. S. DharmarajanDivision of Geriatrics, Department of Medicine,Montefiore Medical Center (Wakefield Campus), Bronx,NY, USA
Albert Einstein College of Medicine, Bronx, NY, USAe-mail: [email protected]
© Springer Nature Switzerland AG 2020C. S. Pitchumoni, T. S. Dharmarajan (eds.), Geriatric Gastroenterology,https://doi.org/10.1007/978-3-319-90761-1_106-1
1
Pulmonary Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Immune-Enhancing Formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Outcomes in Older Adults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Dementia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Older Adults with Severe Neurological Dysphagia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Depression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Orthopedic Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Pressure Ulcers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Adverse Effects Associated with Enteral Nutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Mechanical Complications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Nasoenteric Tube Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Gastrointestinal Intolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Diarrhea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Failure to Attain Nutritional Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Fluid, Electrolyte, and Glucose Abnormalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Refeeding Syndrome (RFS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Key Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Abstract
Enteral nutrition alludes to feeding that utilizesthe gastrointestinal tract to meet the nutritionand hydration needs of an individual in specificsettings. Aging is associated with physiologi-cal changes and complex comorbid conditionsand, in many, frailty, weight loss, and malnu-trition. When older adults are unable to meettheir long-term nutritional needs through thetraditional intake of food and liquids, consid-eration is given to oral supplements and tubefeeding via the gastrointestinal tract. Decision-making regarding long-term artificial nutritionand hydration may be complex and must pri-marily consider the patient’s wishes or existingadvance care planning information in theabsence of decision-making capacity. In theabsence of capacity, the caregiver or healthcareproxy’s preferences are considered, as long asthey are consistent with the patient’s wishes.Decision-making regarding enteral nutritionmay be influenced by ethical dilemmas; culturalor religious beliefs; a lack of understanding of thebenefits and adverse consequences; emotionaldistress surrounding illness; cultural, ethical, and
religious beliefs; and alternate means of feeding.Advance care planning, properly executed, is par-ticularly helpful in enabling decisions regardingthe introduction of enteral nutrition for individ-uals without capacity. Enteral nutrition is pro-vided through the selection of an appropriateformula from numerous options, one that istailored to offer benefits for specific disorders.However, enteral nutrition may also be associ-ated with adverse effects such as metabolic andelectrolyte abnormalities, diarrhea, aspirationpneumonia, and poorer quality of life. The dif-ferent means of enteral support, associated ben-efits, and adverse effects are outlined in thechapter.
Keywords
Enteral nutrition · Oral nutritionalsupplements · Tube feeding · Gastric feeding ·Post-pyloric feeding · Refeeding syndrome ·Enteral formulations · Nasogastric feeding ·Percutaneous endoscopic gastrostomyfeeding · Nutritional supplements and adverseeffects · Indications for enteral nutrition ·
2 M. Kohli et al.
Adverse effects of enteral nutrition · Advancecare planning · Enteral nutrition
Introduction
Older adults, like all individuals, require adequateand balanced nutrition to maintain a healthy life(Rolls 1999; Parker and Chapman 2004). A bal-anced nutritional intake is essential for normalgrowth and vitality; although healthy individualscan be without nutrition for a few days, adequatehydration is always necessary (Baiu and Spain2019). As one gets older, several physiologicalchanges associated with aging, as well as comor-bid health conditions, may influence nutritionalintake. Age-related changes include alterationsin oral health, gut motility, absorption, and declinein musculoskeletal strength and kidney, liver, andcognitive function. Comorbid health disorders,frailty, and declines in cognitive, psychological,functional, and socioeconomic well-being canchallenge the older adults’ accessibility to ade-quate nutrition. As a rule, the preferred means ofnutrition is the use of food, utilizing the gut, aslong as it is functional. The inability to eat may betransient for days or weeks or long term andpermanent (Baiu and Spain 2019). Older individ-uals, particularly with comorbidity, are likely todo poorly without nutrition and hydration even fora few days. Geriatric individuals with inadequatenutritional intake lose weight, develop malnutri-tion, and have poorer clinical outcomes, includingreduced quality of life (Naber et al. 1997;Tappenden et al. 2013; Allard et al. 2016) aswell as higher mortality risk (Wallace et al. 1995).
The prevalence of malnutrition varies and isinfluenced by the living situation, geographicallocation, and age distribution. A meta-analysison malnutrition in older people suggested thatrates of malnutrition were lowest in the outpatientsetting (6.0%) compared to higher rates in hospi-talized patients (22.0%); the highest rates wereamong residents of a rehabilitation setting (17.5–29.4%) (Cereda et al. 2016).
Diagnostic Criteria for Malnutrition
A 2012 consensus statement of the Academy ofNutrition and Dietetics and the American Societyfor Parenteral and Enteral Nutrition (ASPEN)recommended the following criteria for the diag-nosis of malnutrition (White et al. 2012).
Identification of two or more of the followingsix characteristics (recommended for diagnosis):
1. Insufficient energy intake2. Weight loss3. Loss of muscle mass4. Loss of subcutaneous fat5. Localized or generalized fluid accumulation
that may mask weight loss6. Diminished functional status as measured by
handgrip strength
The Global Leadership Initiative on Malnutri-tion (GLIM) introduced new criteria in 2018 con-sistent with a global agreement on theidentification and diagnostic criteria for malnutri-tion. This newer criterion includes an appreciationof the role of acute and chronic inflammation inmalnutrition (Jensen et al. 2019; Ritchie andYukawa 2019).
The diagnosis requires the combination of atleast one phenotype and one etiologic criterion:
• Phenotype criteria:– Non-volitional weight loss– Low body mass index (BMI)– Reduced muscle mass
• Etiologic criteria:– Reduced food intake or absorption– Underlying inflammation due to acute dis-
ease/injury or chronic disease
Pathophysiology of Malnutrition
Frail older adults with self-care deficits who loseweight pose a diagnostic dilemma to healthcareproviders in the community, hospitals, as well as
Enteral Nutrition 3
in skilled nursing facilities. The differential diag-nosis of weight loss and malnutrition is extensive.Causes of weight loss in the geriatric population(Fig. 1) can be broadly grouped into underlyingmedical or psychiatric disorders, medications,
socioeconomic factors, and physiological factors(Table 1).
Socioeconomic factors may range from isola-tion (Locher et al. 2005) and financial difficulty infood acquisition. Abuse or neglect, be it physicalor fiduciary, is not uncommon in older people,especially in those with cognitive and functionalimpairments. Physiological factors associatedwith weight loss include age-related changes intaste and smell perception (Rolls 1999), decreasein the rate of gastric emptying resulting in earlysatiety (Horowitz et al. 1984), and impairment inthe regulation of food intake by alteration of thecentral nervous system sensitivity to digestivehormones (Parker and Chapman 2004). Depres-sion is a common cause of weight loss amongpsychiatric disorders in older people; it is fre-quently encountered in the nursing home settingand a difficult etiology to address among theunintentional causes of weight loss (Morley andKraenzle 1994). Malignancy is another commonmedical cause of undernutrition (Wilson et al.1998). Oropharyngeal dysphagia (due to stroke,Parkinson’s disease, or Zenker’s diverticulum)and esophageal dysphagia (due to achalasia,scleroderma) affect the capability of an individualto have an adequate dietary intake (Achem and
MEDICAL OR PSYCHIATRIC
DISORDERS
MEDICATIONS
SOCIOECONOMIC FACTORS
PHYSIOLOGICAL FACTORS
Fig. 1 Causes of weightloss in older adults(Adapted from Ritchie andYukawa 2019)
Table 1 Medical and psychiatric etiologies of weight loss(Ritchie and Yukawa 2019)
Depression, including bereavement
Dementia
Dysphagia
Malignant disorders
Gastrointestinal disorders (e.g., celiac disease, ischemicbowel disease, inflammatory bowel disease, pancreaticinsufficiency, peptic ulcer disease)
Endocrine disorders (hyperthyroidism)
Substance use disorders
Neurologic disorders (e.g., Parkinson’s disease)
Congestive heart failure
Chronic kidney disease including end-stage renal disease
Chronic obstructive pulmonary disease
Connective tissue disorders (e.g., polymyalgiarheumatica, rheumatoid arthritis)
Infections (especially chronic infections)
Adverse effects of medications used to treat medicalillness (e.g., opioids, serotonin reuptake inhibitors, ACEinhibitors, diuretics, iron supplements, etc.)
4 M. Kohli et al.
Devault 2005). The presence of dysphagia in carerecipients by itself is associated with an increasein caregiver burden, and the presence of feedingtubes to address dysphagia is also associated witha heavy burden. In addition, dysphagia is associ-ated with social isolation, anxiety, and depression;providers need to be cognizant of dysphagia as asource of burden for both the patient and thecaregiver (Namasivayam-MacDonald and Shune2018).
Dementia, particularly moderate to advancedtypes, is associatedwith food preferences, impairedability to choose appropriate healthy foods, reluc-tance to eat and chew the food, and, towards theend stages, with an inability to swallow, resulting inthe concurrent aspiration of food (aspiration pneu-monia); in such patients, the intake of food ismarkedly curtailed. In older people, dysphagiadevelops following a stroke and is of varying degreesbutmay improve partially or entirelywithinweeks ofthe cerebrovascular incident. In the post-strokeperiod, there may be a role for enteral nutrition.
The diagnostic evaluation for the etiology ofmalnutrition can be distressing to older patients andtheir families, especially when the diagnosis isunclear or when the demented patient is unlikelyto cooperate or benefit from an evaluation. Invasivemedical procedures such as screening endoscopiesand contrast imaging studies in frail older peoplemay lead to unintended complications that lead to afurther decline in organ function and poorer qualityof life, with limited to no benefit.
Methods of Nutritional Support
Nutritional support must be tailored to individualpatient needs. Enteral nutrition (EN) is the pre-ferred method for nutritional support in those whohave a functional gastrointestinal tract and cannotconsume adequate food. Providing access for ENdoes not come without risks; choosing the rightapproach matters to attain eventual success (Pash2018). Enteral nutrition alludes to feeding thatuses the gastrointestinal tract to meet nutritionand hydration needs.
An alternative to enteral nutrition is parenteralnutrition, which is artificial feeding that provides
nutrition and hydration directly into the peripheralcirculation bypassing the gastrointestinal tract.Parenteral nutrition is only attempted when thegut is non-functional; the topic is discussed else-where in this work.
Prior to initiating the feed, patient-centeredcare suggests that providers offer the best practiceadvice to those who have or are at risk of malnutri-tion, taking into account the patient’s needs and pref-erences; good communication between healthcareproviders and the patient is paramount, with thehealthcare proxy or caregiver also provided with theopportunity to be involved, if the patient agrees. Amultidisciplinary coordinated team approach inclu-sive of all healthcare professionals involved in thepatient’s care (particularly nutritional support) is key(Fig. 2).
In undernourished patients, the primary approachshould always be to promote oral intake, which isoften possible by recognizing eating preferences,limiting or removing dietary restrictions (Buckleret al. 1994), and, lastly, the addition of nutritionalsupplements.
When oral intake is not feasible or insufficient,enteral nutrition (“tube feedings”) may be required.Enteral nutrition (EN) is the preferred route formeeting long-term nutritional needs compared toparenteral nutrition (PN) and is far better toleratedwith better safety, lower costs, and lesser burden ofcare to the caregiver. EN should always be consid-ered over PN, as long as the former is feasible. PNmay be an option if EN is difficult to initiate or isinsufficient to reach the nutritional target at 7–10 days.
Geriatric patients without contraindications toenteral nutrition should ideally receive earlyenteral feeding (i.e., within 48 h of the precipitatingevent) as potential benefits of early feeding (e.g.,fewer infections) outweigh its risks (Heyland et al.2003; Gramlich et al. 2004; Koretz et al. 2007;Reintam Blaser et al. 2017). In patients with severeneurological dysphagia, EN plays a significant rolein ensuring energy and nutrient supply to maintainand improve nutritional status (Volkert et al. 2006).
Percutaneous endoscopic gastrostomy (PEG)should be considered in cases where resumptionof normal eating is expected to be delayed (e.g., incases of neurological dysphagia following a
Enteral Nutrition 5
stroke) since it is associated with fewer treatmentfailures and perhaps better nutritional status(Table 2). For patients with terminal dementia,tube feeding is generally not recommended; thetopic is extensively discussed in another chapter(Volkert et al. 2006).
Oral Nutritional Supplements
The initial approach in improving nutritional sta-tus is to improve regular oral food intake. Treat-ment of the underlying cause is often essential.The patient should undergo a diet recall assess-ment to understand nutrient intake, requirements,and preferences (relating to ethnic, cultural, andregional backgrounds). A food intake diary helpsdetermine solutions and timely follow-up to assessresponse. In nursing homes, malnourished statesmay be related to needless dietary restrictions (Buck-ler et al. 1994). In general, liberal diets during the lastfew years of life may improve the quality of life. Onemust also ensure easy and adequate access to food(including feeding and shopping for food).
If no initial improvement is observed followingthe basic measures, increasing nutrient density offood may be considered (e.g., the addition of milk
powder for protein, oils for fat, liquid nutritionalsupplements such as “Boost,” or nutrient-densesnack bars) along with daily micronutrient sup-plementation. If no improvement is observed fol-lowing the use of supplements over severalweeks, it may be appropriate to consider EN.
Enteral Nutrition
Enteral nutrition refers to the provision of artificialnutritional support to provide calories inclusive ofprotein, electrolytes, vitamins, minerals, trace ele-ments, and fluids via the gut. Compared to PN, ENhas a better ability to stimulate and maintain gas-trointestinal mucosal health and is more efficientlyutilized by the body. Enteral feeding delivers anutritionally complete feed directly into the gutvia a tube. By maintaining the function of themucosal barrier, EN minimizes the risk of over-feeding, infection-related complications, and labileglucose control (Heyland et al. 1998; Zaloga 2006;Jeejeebhoy 2007).
(A) Route of DeliveryNasoenteric tubes (NET) are any feeding
tubes that are inserted nasally, and depending
Methods of Nutritional Support
Oral Nutritional Supplements
Promote Oral Intake
Limit Dietary Restrictions
Nutrional Supplements
Enteral Nutrition
Tube feeding
Nasogastric Feeding
Post-Pyloric Feeding
Percutaneous Gastrostomies
Parenteral Nutrition
Fig. 2 Methods of nutritional support
6 M. Kohli et al.
on desired end-tip location, they are referredto as nasogastric(NG), naso-duodenal, ornaso-jejunal (Pash 2018). The route of deliv-ery of EN is dependent on indications. NETsare the primary means of enteral access inmost patients. Placement of NETs offers atemporary solution, while a more permanentfeeding tube (percutaneous gastrostomy tubeor “PEG”) may need to be considered ifenteral support may be required for morethan 4 weeks (American GastroenterologicalAssociation Medical Position Statement 1995;Kirby et al. 1995). Considering the surgicalrisks of PEG tubes placements, it may be rele-vant to initially assess GI tolerance by feedingvia a NET before PEG placement. In a study of102 older subjects, mean age of 82.67 years, acomparison of NG with gastrostomy feedingsuggested that gastrostomy feeding was asso-ciatedwith a greater 4-month complication-freesurvival and fewer tube-related complications
but with no differences in nutrition outcomes(Jaafar et al. 2019).
Though most patients tolerate intragastricfeedingwell, patients with recurrent pulmonaryaspiration, recurrent emesis, severe gastro-esophageal reflux, and impaired gastric motil-ity and those who have had bariatric surgery orgastrectomy may require post-pyloric feeding.
(B) Method of Tube Placement(a) Gastric Feeding
Nasogastric tubes (NGTs) can be placedviamultiple techniques, with themost com-mon being blind trans-nasal placement.
Commonly required equipment includesa nasogastric tube, glass of water for thepatient to sip on, water-soluble lubricantjelly, catheter tip syringe, stethoscope, andmaterials to maintain a sterile field (e.g.,gloves, towel, and emesis basin).
The ideal position for the patient issitting up. Determine the length of thetube to be inserted; the total distance is
Table 2 Enteral nutrition vs. parenteral nutrition (Hoffer et al. 2018; Seres 2019, 2020)
Enteral nutrition Parenteral nutrition
Enteral nutrition alludes to feeding that uses thegastrointestinal tract to meet nutrition and hydrationneeds
Parenteral nutrition alludes to artificial feeding thatprovides nutrition and hydration directly into theperipheral circulation bypassing the gastrointestinal tract
Preferred method for nutritional support in patients whohave a functional gastrointestinal tract and cannotconsume adequate food
PN is the option if EN is difficult to initiate or isinsufficient to reach the nutritional target at 7–10 days
Preferred for meeting long-term nutritional needs Attempted when the gut is non-functional
Better tolerated with better safety, lower cost, and lesserburden of care considerations
Costlier, more resource-intensive, potentially riskier, andrequires more expertise than EN
Mechanical complications Bloodstream infections: access to venous system isrequired for PN. Patients have a higher risk of acquiringbacterial and fungal bloodstream infections (compared topatients with central venous access not receiving PN)(Kritchevsky et al. 2008)
Tube related, insertion related, or traumatic placement Complications related to venous access (bleeding,vascular injury, pneumothorax, venous thrombosis,arrhythmia, and air embolism)
Non-mechanical complications Metabolic complications, e.g., hyperglycemia (Petrov andZagainov 2007), hypoglycemia, hypertriglyceridemia, andvolume overload
Infectious
Metabolic
Pulmonary (particularly aspiration)
Gastrointestinal
Other
(Adverse effects associated with EN discussed in greaterdetail in the chapter)
Enteral Nutrition 7
from the nose to the pinna of the ear andfrom the pinna to the xiphoid process. Agentle arc is prepared with the tube whileavoiding any acute bends. The nostrilsand the tube are well lubricated using awater-soluble lubricant.
With the patients extending his neck,gently insert the tube with the curve of thetube pointing downwards. The tube isslowly progressed, going along the floorof the nasal passage until it roughly passesthe nasopharynx. At this stage, the patientflexes his neck forwards and is given aglass of water to sip on. Advance the tube1–2 inches with each swallow; once themeasured mark is reached, anchor the tubein position. The correct positioning of thetube is demonstrated by injecting 30 cc ofair down the tube while auscultating theepigastric region, and a blast of bubbles isexpected to be heard. Though this maneu-ver is commonly used, it is not diagnosticand not specific for the tube position in thestomach; as a rule, radiographs must beperformed to confirm placement beforestarting feeding. Tubes have been knownto be in abnormal positions, includingcoiling in the esophagus or turning aroundto be in the neck or rarely perforate theesophagus. Aspiration of light-coloredsecretions that are cloudy or with minimalbile suggests intragastric position.
(b) Post-Pyloric FeedingIn cases where post-pyloric feeding is
indicated, feeding tubes can be passedfurther down into the duodenum or eveninto the jejunum via manual, endoscopic,or radiological techniques.(i) Manual techniques: Post-pyloric
placement is often more challengingdue to the anatomic position of thepylorus with respect to the body ofthe stomach. In addition to the pro-cess described above, adjunctivetechniques such as administrationof prokinetic drugs (Griffith et al.2003) (e.g., erythromycin) beforetube insertion, possibly along with
certain maneuvers such as inflatingthe stomach with 500 cc air (Slagt etal. 2004), can improve placementrates. For duodenal placement, theuse of electromagnetic sensingdevices such as the “Cortrak” ishelpful (Taylor et al. 2010).
(ii) Radiological or fluoroscopic tech-niques: The failure of manual inser-tion is an indication for insertionunder radiological guidance. NETplacement under fluoroscopic guid-ance is successful in 90% of cases(Ott et al. 1991).
(iii) Endoscopic techniques: Endoscopictechniques are often used after fluo-roscopic failure. Endoscopy allows fordirect visualization minimizing muco-sal trauma and decreasing chances ofmisplacement. Endoscopy facilitatesguidewire deployment, allowing thelubricated feeding tube to be fed overthe wire and pushed into position.
Correct post-pyloric placement issuggested by the return of darkerbilious secretions on aspiration.
(c) Percutaneous Endoscopic Gastrostomy(PEG)
The topic is discussed in depth in otherchapters in the book
(C) Practical Aspects for EN(a) Nasogastric Feeding
(i) Position of the patient: Patients receiv-ing EN should be ideally seated withthe upper body at 30–45�.
(ii) Initiation of enteral feeding: Therequired enteral nutrition should betailored as per the specific needs ofthe patient. The usual target in a crit-ically ill patient of average weight isaround 25 Kcal/kg/day. Feeding canbe initiated with two possible strate-gies, either slowly increasing theinfusion rate until the target mainte-nance rate is achieved (low-volumeor initial trophic feeding) or initiatingthe infusion at the target maintenancerate (full enteral feeding).
8 M. Kohli et al.
Initial trophic enteral feeding isinitiated at 30% of maintenance tar-get (10–30 ml/h) for a few days,followed by advancing the rate by25 ml/h every 6 h until the targetrate is reached. Before each rateincrease, gastric residual volume ismeasured in appropriate clinical set-tings. The incremental infusionmethod is associated with lesser gas-trointestinal intolerance (smaller gas-tric residual volumes and lesserconstipation and vomiting) (Rice etal. 2012; Seres 2019). Approaches tomeasure the gastric residual volumesare controversial, including the gas-tric residual amounts that are consid-ered normal or abnormal.
(iii) Techniques for delivery of EN: ENcan be administered by continuous,cyclic, intermittent, or bolus tech-niques (Table 3). Previous studiesfound no differences in mortality,infections, or ICU length of staybetween the continuous and inter-mittent approaches (Bonten et al.1996; Steevens et al. 2002; Mac-Leod et al. 2007). However, EN istypically administered as continu-ous, or cycled infusion, particularlyin patients with a higher risk ofvomiting or reflux (Table 4).
(iv) Monitoring: The clinical practice ofchecking patient’s gastric residualvolume (GRV) at regular intervalsand/or prior to increasing the infusionrate has now been shown to lack ben-efit and is no longer recommended(Reignier et al. 2013). If GRV isused as a marker for risk of aspira-tion, volumes of 500 ml or lessshould not result in holding thefeeds in the absence of other clinicalfeatures such as abdominal disten-sion, nausea, or vomiting (Mentec etal. 2001; McClave et al. 2005;Montejo et al. 2010).
(b) Post-Pyloric Feeding(i) The position of the patient and the
initiation of feeding are similar to thatof nasogastric feeding. Bolus feedingis never utilized in the small intestine,and the use of continuous feeding tothe jejunum prevents gastric disten-tion, potentially decreasing the risk ofaspiration pneumonia (Montecalvo etal. 1992; Alkhawaja et al. 2015). Themain disadvantages of post-pyloricfeeding are difficulty in tube place-ment and frequent occlusion of thetubes. Jejunal tubes are of a finer borecompared to that of gastric tubes andhence do not allow easy administrationof solid medications and viscous feedsthrough them. Jejunal tubes requirefrequent flushing with tap water every6–8 h.
(D) Advantages and Disadvantages of EN(E) Contraindications to Tube Feeding
Mechanical obstruction (e.g., esophagealstricture, gastric outlet pathology), intestinalischemia, peritonitis, and gastrointestinalhemorrhage are absolute contraindications toEN (Hoffer et al. 2018). Depending on theroute of EN chosen, relative contraindicationsare outlined in Table 5.
Enteral Formulations
Over the past few decades, several enteral formu-lations consisting of varying mixtures of protein,carbohydrate, and fats are available for a varietyof indications. Patient-related (e.g., nutritionalrequirement, organ dysfunction, type of enteralaccess, or volume status) and formula-related (e.g., caloric density, osmolality, composition) fac-tors need consideration before initiating their use(Escuro and Hummell 2016). The formulas differin osmolarity, caloric density, amount of protein,
Enteral Nutrition 9
carbohydrate, and fat per 100 ml, electrolyte, andmicronutrient content; they fall into severalcategories.
Standard Polymeric Formula
(A) Most commonly used for patients requiringEN support and mimic a regular diet by pro-viding carbohydrate, protein, and fat in non-hydrolyzed forms. Normal digestive functionis required for polymeric formulas. They meetthe basic nutrition needs of most non-criticallyill patients. The standard formulas are isotonicto serum and have a caloric density or
approximately 1 Kcal/ml. Typically 1–1.5 lof formula provides 100% of RecommendedDietaryAllowances (RDAs) for mostmineralsand vitamins. Standard polymeric formulasare generally lactose and gluten-free as wellas kosher.
(B) Concentrated polymeric formulas may beuseful in critically ill patients requiring fluidrestriction, such as patients with renal failure,heart failure, syndrome of inappropriate anti-diuretic hormone (SIADH), ascites, or fluidoverload. Compared to the standard poly-meric formula, they have a higher caloricdensity (1.2–2 Kcal/ml) and are mildly hyper-osmolar to serum (Brown et al. 2015; Escuro
Table 3 The techniques for delivery of EN. (Adapted from Ichimaru (2018) and Blumenstein et al. (2014))
Feedingmethod Administration Comments
Continuous Administration over 24 h assisted byfeeding pump
Used in critically ill (often bedridden) patients
Used in patients who cannot tolerate intermittent or bolusfeeds
Advantages: Higher time for nutrient absorption, mayimprove tolerance, and can be used for gastric and post-pyloric feeding
Disadvantages: Expensive, requires feeding pump, andrestricts ambulation
Cyclic Administration over a period less than24 h assisted by feeding pump
Infusion rate calculated by dividing the desired feedingvolume by the number of hours of administration
Can be used to transition patients from continuous tonocturnal feeding to stimulate the patient’s appetite duringthe day
Advantages: Allows for greater patient mobility (when notreceiving EN); daytime cessation of feeds may stimulatepatient appetite
Disadvantages: Expensive, requires feeding pump, andhigher infusion rates when compared to continuous feedingmay lead to intolerance (as shorter administration time)
Intermittent Administration over 20–60 min every4–6 h via pump assist or gravity assist
More physiological than continuous and cyclic feeding
Advantages: Allows for greater patient mobility betweenfeedings; a feeding pump may not be required
Used for patients who do not tolerate bolus feeding
Disadvantages: Increased risk for aspiration and can lead todelayed gastric emptying
Bolus Administered over 4–10 min every 4–6 h via syringe or gravity drip
Used in ambulatory patients
Rapid infusion of feeds provided
Advantages: Closely resembles normal eating patterns,increases the time away from feeding allowing for greatermobility and freedom
Enhanced quality of life
Disadvantages: Higher risk of diarrhea and aspiration
10 M. Kohli et al.
and Hummell 2016). Concentrated formulasdo not result in mortality benefit, ventilator-free days, or duration of hospital stay whencompared to standard formulations (Chapmanet al. 2018). The concentrated formulas areparticularly useful during the weaning period(e.g., transitioning from EN to oral intake dur-ing acute rehabilitation) while on bolus feed-ing schedules (possibly stimulates hunger andfacilitates weaning (Corrigan et al. 2011)).
Fiber Containing Formula
Fiber-containing EN formulas are often selectedto improve gastrointestinal (GI) health and helpmaintain GI motility. Fiber-containing EN formu-las may contain prebiotic fibers such as fructooligo-saccharide, oligofructose, and insulin, which possiblyimprove immunity by affecting gut-associated lym-phoid tissue as well as bowel function. Though theseformulations contain fiber, the fiber amounts are wellbelow the daily recommendations. Their use in crit-ically ill patients remains controversial, given insuf-ficient research and a theoretical risk of complications(Scaife et al. 1999; McClave and Chang 2003;Brown et al. 2015; Escuro and Hummell 2016).
Predigested
These formulas are intended for those with ma-labsorptive disorders (e.g., malabsorption, pancre-atic dysfunction), and not for routine use. Theydiffer from the standard formula in that the macro-nutrient content is partially (semi-elemental) orcompletely hydrolyzed and designed to maximizeabsorption (Brown et al. 2015; Escuro and
Table 4 Advantages and disadvantages of EN. (Adapted from Heuschkel and Duggan (2019))
Intragastric feeding Post-pyloric feeding
Advantages Nutrition provided in a more physiological route(Valentine et al. 1986)
By directly feeding beyond the pylorus, post-pyloric feeding reduces the risks associated withhigh gastric residuals such as aspirationpneumonia (Montecalvo et al. 1992; Jiyong et al.2013)
A relatively safer procedure for insertion whichrequires minimal training; done at the bedside
Intragastric feeding allows for theadministration of larger volumes and higherosmotic loads
May be the only option in those who had bariatricsurgery or do not have a stomach
Feeding can be either intermittent (bolus) orcontinuous
Disadvantages Difficult administration of bolus feeds in caseswith delayed gastric emptying; here, the patientrequires continuous intragastric feeds
Difficult insertion and placement compared togastric tubes
Can worsen gastroesophageal reflux Jejunal tubes are of a smaller bore, not allowingfor the administration of viscous feeds andmedications
Higher chances of aspiration compared to post-pyloric feeding
High tendency to occlude
Cannot be used to administer bolus (intermittent)feeds
Require frequent flushing with tap water
Table 5 Contraindications to tube feeding. (Adaptedfrom Hoffer et al. (2018) and Scott and Bowling (2015))
Route Contraindications
Nasoenterictube feeding
Esophageal varices
Basilar skull or facial fracture(Başkaya 1999; Ferreras et al. 2000)Absent gag reflex
Severe hemodynamic instability
Intestinal ileus
PEG feeding Gastric varices
Significant ascites
Active gastric ulceration
Uncorrected coagulopathy
Severe hemodynamic instability
Intestinal ileus
Enteral Nutrition 11
Hummell 2016) (e.g., proteins to short-chainpeptides).
Blenderized Formulas
Blenderized formulas are typically prepared athome by blending food into a liquid and thenadministered through a feeding tube. They areoften a combination of home foods along withcommercially available formulations or commer-cial pureed baby foods (Brown et al. 2015; Escuroand Hummell 2016). Several studies suggestblenderized tube feeds contain unsafe levels ofbacterial contaminants and do not deliver consis-tent nutrients, making them a less desirable optionin hospital and acute care facilities (Sullivan et al.2004; Baniardalan et al. 2014). Blenderized tubefeeds can be considered only for medically stablepatients with safe food practices and tube mainte-nance techniques. These feeds may increase therisk of tube occlusion if the tube is not flushedappropriately; such feeds should only be admin-istered as a bolus infusion, not lasting more than2 h. They are not suitable for patients with lessthan a 14 French feeding tube (Bobo 2016).
Disease-Specific Formulas
Disease-specific specialized formulas are intendedfor patients with specific disease states such asdiabetes mellitus, renal, hepatic, and pulmonarydisease. The costmay be higher for disease-specificcompared to standard formulations.
Diabetes Mellitus (Type 2)
Diabetes-specific EN formulas are typically lowglycemic index formulas designed to decrease thelikelihood of hyperglycemia. Compared withstandard formulas, diabetes-specific EN formulashaving a different macronutrient composition areintended to improve blood glucose control(Brown et al. 2015; Escuro and Hummell 2016).Although the use of these products may improveglycemic control, there remains a need for further
research with regard to the clinical impact of theseformulas, particularly in hospitalized patients(McMahon et al. 2013).
Hepatic Disease
Formulations for acute and chronic liver diseaseare characterized by a low protein contentcontaining higher amounts of branched-chainamino acids (BCAAs) and lesser amounts of aro-matic amino acids (AAAs) (Brown et al. 2015).Individuals with cirrhosis utilize BCAAs (leucine,isoleucine, and valine) in the skeletal muscle toproduce glutamine, which acts as an energysource, in turn, reducing BCAA levels. Moreover,in cirrhosis, patients are unable to metabolizeAAAs (tryptophan, tyrosine, and phenylalanine)well, resulting in higher AAA levels (Escuro andHummell 2016). BCAA containing EN formulasimprove the disturbed amino acid profile, reduc-ing signs and symptoms of hepatic encephalopa-thy (Juneja and O’Keefe 2012). Guidelinesrecommend the use of standard EN formulationsin critical care unit patients with acute and chronicliver disease. There is no evidence that the use ofhepatic formulations reverses hepatic encephalop-athy in those patients already receiving first-linetherapy with antibiotics and lactulose (McClave etal. 2016).
Chronic Kidney Disease
Renal disease-specific EN formulas are typicallyfluid restricted and contain lower amounts of elec-trolytes (magnesium, potassium, phosphorus, andsodium). These formulas are differentiated by theamount and type of protein they contain. Protein-restricted formulas are intended for patients withchronic kidney disease (CKD) who are not receiv-ing dialysis, while other formulas with higherprotein content are meant to meet the catabolicneeds for CKD patients undergoing dialysis.There are no renal formulas for AKI, and currentrecommendations are for critically ill patientsundergoing continuous renal replacement therapy
12 M. Kohli et al.
receive standard EN formula (Brown et al. 2015;Escuro and Hummell 2016).
Pulmonary Disease
Pulmonary disease-specific enteral formulas wereoriginally developed to assist patients in weaningoff mechanical ventilation. In efforts to reducecarbon dioxide production, these formulas arehigh in fat content, lower in carbohydrate content,and similar in protein content compared to stan-dard polymeric formulas (Brown et al. 2015).With the augmentation of these formulas withimmune-modulating enrichments, they have sub-sequently been used for patients with acute lunginjury (ALI) and acute respiratory distress syn-drome (ARDS) (Escuro and Hummell 2016).According to the ASPEN guidelines, pulmonaryformulas (low carbohydrate, high fat) are notrecommended for patients with acute respiratoryfailure. Guidelines further suggest the use of fluid-restricted energy-dense EN formulations forpatients with acute respiratory failure (especiallyif in a state of volume overload) (McClave et al.2016).
Immune-Enhancing Formula
Immune-enhancing formulas (IEF) are designedto modulate the immune response and deliveradequate nutrition. These formulas contain vari-ous combinations of enrichments with nutrientsacknowledged to have an effect on inflammation,e.g., arginine, glutamine, ω-3 fatty acids, and anti-oxidants. IEFs differ in the combination andamounts of these immune-modulating ingredients(Brown et al. 2015; Escuro and Hummell 2016;Hoffer et al. 2018). Administration of IEF can beconsidered for patients with traumatic brain injuryor those undergoing elective surgery. However,research is not sufficient to recommend the rou-tine use of IEF in critically ill patients at this time(McClave et al. 2016).
Outcomes in Older Adults
General
Appropriate use of EN in geriatric patientsincreases energy and nutrient intake, with PEGfeeding being superior to NGT feeding in thisrespect. The use of oral nutritional supplementscan improve nutritional status in undernourishedpatients or those at risk of undernutrition (Volkertet al. 2006).
Dementia
Patients with advanced dementia experience inad-equate nutritional intake towards the end of life.Undernutrition in these patients is usually multi-factorial, relating to cognitive impairment andpoor judgment, polypharmacy, depression, dys-phagia, dental issues, and a decline in appetite.There is no evidence that EN or PN improvesquality or length of life in those with advanceddementia (Hoffer et al. 2018). Previous ESPENguidelines (2006) recommended ONS or tubefeeding as beneficial for nutritional status indementia, especially in early and moderate demen-tia, to ensure adequate energy and nutrient supply(Grade C recommendation). The statement furtherstates that tube feeding is not recommended inpatients with advanced dementia (Grade C recom-mendation) (Volkert et al. 2006). The AmericanGeriatrics Society position statement (in 2014) rec-ommends against the use of feeding tubes for olderadults with advanced dementia (American Geriat-rics Society Ethics Committee and Clinical Prac-tice andModels of Care Committee 2014). Patientsshould be offered careful hand feeding, and effortsmust be taken to enhance oral feeding by ensuring afavorable environment and creating patient-cen-tered approaches to feeding as part of usual carefor geriatric adults with advanced dementia. Thedecision, in each case, must be made on an indi-vidualized basis (Volkert et al. 2006), often basedon advance directives or the opinion of the individ-ual’s surrogate decision-maker (American Geriat-rics Society Ethics Committee and ClinicalPractice and Models of Care Committee 2014).
Enteral Nutrition 13
Despite the research-based evidence and sug-gestions to forgo EN in those with advanceddementia and dysphagia, the practice neverthelesscontinues, questioning the matter of ethical prin-ciples involved (Schwartz 2018). Physiciansshould view advanced dementia as a terminaldisorder and factor the provision of enteral nutri-tion in conjunction with overall goals of care,prognosis, and palliative care principles (Arcand2015a). In this context, it is worth emphasizingthat feeding tubes are not recommended in end-stage dementia; rather, comfort feeding by hand ispreferred as it is consistent with patient comfortand facilitates social interactions, while tube feed-ing may be associated with aspiration and poorerquality of life (Arcand 2015b). Survival periodsfollowing PEG feeding in older adults withdementia are poor; in a study of 184 patientswith dementia and poor nutritional status, meanage 82.2 years; EN was utilized in 54 cases; thesurvival was significantly shorter in the EN groupversus those on oral feeds, suggesting that EN wasa significant predictor of death (Ticinesi et al.2016).
An ongoing US nationally representative lon-gitudinal study of over 1400 older adults suggeststhat comfort eating, irrespective of consuminghigh fat/sugar food, may be associated withreduced mortality in geriatric patients becausethe approach promotes greater body mass, a factorassociated with lower mortality (Cummings et al.2018). The goals of care in advanced dementia areto maintain quality of life, dignity, and comfortand to avoid resorting to aggressive, expensivemedical interventions that may not be in the bestinterests of the patient; tube feeding is similar to arestraint that does not promote dignity, comfort, orquality of life (Volicer 2007). Nurses must beinvolved in the decision-making process; theirabilities to establish good relationships and theirattitudes help create teamwork and closeness topatients and family; it is also essential to developdeep clinical and ethical knowledge about artifi-cial nutrition and hydration to provide consistentand adequate care at the end of life (Albanesi et al.2020).
Older Adults with Severe NeurologicalDysphagia
Geriatric patients with severe neurological dys-phagia (e.g., following a stroke) may requirelong-term nutritional support. EN is oftenrecommended to ensure adequate energy andnutrient supply. PEG feeding is preferred overNG feeding in this setting, considering it is asso-ciated with fewer treatment failures (Gomes et al.2015) and better nutritional status and may also bemore convenient for the patient (Volkert et al.2006). Compared to NGT feeding, PEG feedingwas also associated with reduced gastrointestinalbleeding and had higher feed delivery and albu-min concentration (Geeganage et al. 2012). On theother hand, a prospective study of 201 adults froma stroke unit revealed that patients with dysphagiawere older and had a higher severity of stroke andpneumonia rate; while pneumonia was the leadingcause of death, the very presence of dysphagianecessitating tube feeding appeared to be a markerof poor prognosis. The implications are for earlyevaluation of dysphagia and close monitoring ofpatients who are tube-fed after a stroke (Souza etal. 2019).
Depression
Depression is a common cause of unintentionalweight loss in older people (Thompson and Mor-ris 1991; Morley and Kraenzle 1994; Wilson et al.1998) but often remains undiagnosed. Anorexiaand refusal to eat are common manifestations ofdepression. Improving oral dietary intake shouldbe the first step to prevent undernutrition andassociated complications. ESPEN guidelines rec-ommend the use of EN to support the patientduring the early phase of severe anorexia andloss of motivation (Grade C recommendation)(Volkert et al. 2006).
Orthopedic Surgery
Geriatric patients are at higher risk of falls, withconsequent fractures often requiring orthopedic
14 M. Kohli et al.
interventions. Voluntary oral intake may be insuf-ficient to meet the enhanced nutritional needs fol-lowing orthopedic surgery. ONS is recommendedafter hip fracture and orthopedic surgery in order toreduce complications (Volkert et al. 2006) andmeetthe increased requirements of energy, protein, andmicronutrients following surgery. Perioperativenutrition is detailed in another chapter. As a generalcomment, older adults eat poorly in the postopera-tive period and perhaps after trauma, in the preop-erative period. In a study of older patients with hipfracture, those who received early enteral nutritionspent a shorter period of time in bed versus thecontrol group; in those receiving EN, the postop-erative IL-6 levels were lower, healing was faster,and the quality of life was better (Shi et al. 2020).
Pressure Ulcers
Clinical experience suggests wound healing ingeriatric patients may be improved by the admin-istration of supplements containing protein andcertain micronutrients (Quain and Khardori2015) (that are involved in wound healing, e.g.,zinc (Heintschel and Heuberger 2017), arginine,carotenoids, vitamins A, C, and E). These nutri-ents should be provided on a short-term basis andin reasonable doses. However, far more crucial aremeasures to ensure the correct and regularrepositioning of the patient to alleviate pressure,ensuring adequate local circulation and relief ofpressure in the ulcer area. Additionally, healingand prevention of pressure ulcers need adequatenutrition (Volkert et al. 2006).
Adverse Effects Associated withEnteral Nutrition
Besides mechanical complications, enteral nutri-tion is associated with infections and pulmonary,gastrointestinal, metabolic, and electrolyte disor-ders as summarized in Table 6.
Mechanical Complications
Mechanical complications associated with EN canbe tube related, insertion related, or secondary totraumatic placement (Table 6). Tubes may occludedue to kinking, due to coagulation of feeding for-mula within the tube, or due to occlusion frommedication fragments. Additionally, crushed tab-lets and opened capsule administration throughNETsmay lead to altered absorption or interactionswith enteral feeds. Long-acting or time-releasedmedications should not be crushed. Care of feedingtubes requires frequent tube flushing with water toprevent occlusion, before and after medicationadministration, and bolus feeds and at regular inter-vals (Prabhakaran et al. 2012). Medications areperhaps the most common cause of tube occlusion.
Nasoenteric Tube Syndrome
The NET syndrome is characterized by the triad ofnasoenteric intubation, throat pain, and vocal cordparalysis (usually bilateral). Symptoms includethroat pain, stridor, dysphagia, hoarseness, and lesscommonly dyspnea, otalgia, and fever (Prabhakaranet al. 2012).
Gastrointestinal Intolerance
The most common adverse effects associated withEN involveGI function (Montejo 1999; Blumensteinet al. 2014). They include abdominal discomfort,distention, high gastric residual volumes, nausea,diarrhea, and constipation, all distressing for patients.Furthermore, they can increase the nursing burdenand delay the progression of EN. Adequate symptomcontrol by ensuring normal fluid and electrolyte bal-ance, avoiding severe hypoglycemia and hyperglyce-mia, and judicious use of antiemetic and prokineticdrugs can help minimize these effects (Hoffer et al.2018).
Enteral Nutrition 15
Diarrhea
Diarrhea is common when bowel function iscompromised by disease or drugs and is oftenchallenging to manage. Luft et al. demonstratedan incidence of diarrhea at 18% among patients onmedical and surgical wards receiving enteralnutrition compared to only 6% in patients who
did not receive EN (Luft et al. 2008). Alteration ofintestinal transit or the intestinal microflora hasbeen proposed as one of the underlying causes,though the exact mechanism is unknown (Seres2019). The pathogenesis of diarrhea in enterallyfed patients is multifactorial. It includes concom-itant administration of medications that can causediarrhea (e.g., antibiotics, proton pump inhibitors,
Table 6 Adverse effects associated with EN. (Adapted from Halloran et al. 2011; Prabhakaran et al. 2012; Blumensteinet al. 2014; Scott and Bowling 2015; Hoffer et al. 2018)
Mechanical 1. Tube related Tube obstruction/mechanical occlusion
Break in the tube and leakage
Knotting of tube (Mandal and Foxell 2000)
Tube occlusion relating to medications
2. Insertion related Primary malposition (Sorokin and Gottlieb 2006)
Accidental tube displacement and removal
Hypertensive response to tube insertion (Bremner 1993)
3.Traumatic placement Perforation of intestinal tract
Creating of nasal submucosal passage (Lind and Wallace 1978)
Erosion, ulceration, and necrosis of skin and mucosa
Esophageal stricture formation (Zaninotto et al. 1986)
Nasoenteric tube syndrome (Sofferman et al. 1990; Brousseau andKost 2006)
Intracranial insertion in patients with facial trauma or recent facialsurgery (Başkaya 1999; Nathoo and Nadvi 1999; Ferreras et al.2000; Genu et al. 2004)
Non-mechanical
1. Infectious Inadvertent intravenous infusion of enteral diet
Infection at the tube insertion site
Rhinitis and sinusitis (Desmond et al. 1991)
Infective diarrhea
Peritonitis (following perforation)
2. Metabolic Electrolyte disturbances of sodium and water
Hypo- and hyperglycemia
Vitamin and trace element deficiencies
Refeeding syndrome
3. Pulmonary (followingmalposition)
Aspiration
Pneumothorax (Culpepper et al. 1982; Carrillo et al. 1998;Weinberg and Skewes 2006)
Empyema (Torrington and Bowman 1981) and pulmonary abscessformation
4. Gastrointestinal (Montejo1999; Blumenstein et al. 2014)
Diarrhea
Nausea and vomiting
Cramps and bloating
Regurgitation and aspiration
Constipation
5. Other Poor tolerance to feeding
Failure to reach nutritional goal
Drug interactions with feeds and other medications
Improper medication absorption (Prabhakaran et al. 2012)
16 M. Kohli et al.
laxatives) and, rarely, contaminated feeds (Scottand Bowling 2015; Seres 2019). Medications inthe liquid formulation may contain sorbitol, whichis an added reason for diarrhea, in addition to theproperties of the medication itself. Managementof diarrhea includes reviewing and managing thepotential underlying causes, including a review ofactive medications, and ruling out infectious pro-cesses, including Clostridium difficile, E. coli, andKlebsiella-related etiology (Blumenstein et al.2014; Scott and Bowling 2015). Unless severe,EN should not be discontinued for diarrhea andshould be continued while the etiology is beinginvestigated. Treatment should address symptom-atic control. Slowing down the feed rate, judicioususe of antidiarrheal medications, changing formu-lations, or changing to a different mode of deliv-ery may be successful in resolving the matter(Blumenstein et al. 2014; Scott and Bowling2015). Fiber-rich formulations are an acceptedtherapeutic intervention for EN-associated diar-rhea if the resolution of the underlying cause hasbeen unsuccessful (Rushdi et al. 2004; KamarulZaman et al. 2015).
Failure to Attain Nutritional Goal
Medically active patients frequently require diag-nostic testing, clinical procedures, or physical/occupational therapy leading to delays in initia-tion or interruptions in EN. Patients may alsoencounter mechanical complications like cloggedtubes or experience intolerance to EN. These con-ditions lead to a delay in the successful implemen-tation of EN and a failure to meet the patient’snutrient requirements and goals (Hoffer et al.2018).
Fluid, Electrolyte, and GlucoseAbnormalities
Enteral formulas are primarily designed to providemacronutrients along with standard amounts offluids, electrolytes, minerals, and micronutrients.Accommodation of patient’s clinical needs can beattempted by selecting an appropriate EN formula
though they are not intended to address metabolicor electrolyte abnormalities (Hoffer et al. 2018).The patient may require more frequent monitoringof fluid status, electrolyte levels, and blood glucoselevels, especially in the critically ill stages (Junejaand O’Keefe 2012; Hoffer et al. 2018; Seres 2019).
Refeeding Syndrome (RFS)
RFS can be defined as the potentially fatal shifts influids and electrolytes that may occur upon thereinstitution of oral, enteral, or parenteral nutritionin malnourished patients (Table 7). The patho-physiology of refeeding syndrome remains poorlyunderstood. During prolonged fasting or phases ofundernutrition, themetabolic and hormonal changesin the body are aimed at conserving energy. Thebody adjusts by downregulatingmembrane functionto conserve energy, causing leakage of intracellularpotassium, magnesium, calcium, and phosphate,leading to subsequent whole-body depletion. Con-currently, sodium and water also leak into the cells.Sudden refeeding reverses these processes and,along with insulin (released in response to glyce-mia), drives electrolytes into the cells. These pro-cesses result in a precipitous decrease in the serumlevels of phosphate, potassium, and magnesium, allof which are already depleted (Mehanna et al. 2008;Blumenstein et al. 2014).
The hallmark biochemical feature of RFS ishypophosphatemia, which is responsible for sig-nificant morbidity andmortality. It can manifest ascardiac arrhythmia, rhabdomyolysis, respiratoryfailure, cardiac failure, hypotension, seizure, coma,and sudden death (Blumenstein et al. 2014). Addi-tionally, thiamine deficiency, hypokalemia, hypo-magnesemia, sodium and fluid imbalance, andabnormalities in glucose, protein, and fat metabo-lism are commonly observed, which again lead tosignificant adverse events and possibly multi-organfailure (Mehanna et al. 2008; Blumenstein et al.2014).
The National Institute for Health and CareExcellence (NICE) details the criteria for the iden-tification of patients at high risk of RFS along withthe recommendations for therapy and prevention(National Institute for Health and Clinical
Enteral Nutrition 17
Excellence 2006). High-risk patients include pa-tients with anorexia nervosa, chronic alcoholism,malignancy, postoperative patients, poorly con-trolled DM, chronic malnutrition, and in associationwith long-term antacids and diuretics. Geriatricpatients with multiple medical comorbidities anddecreased functional reserves are considered highrisk. Serum phosphate, magnesium, calcium, potas-sium, urea, and creatinine concentrations should bemeasured before feeding and repeated regularly dur-ing the first week after feeding is initiated. Gradualintroduction and slow advancement of feedingwhile closely monitoring laboratory data and
supplementation of essential electrolytes remainthe cornerstone for prevention and treatment(National Institute for Health and Clinical Excel-lence 2006; Mehanna et al. 2008; Blumenstein etal. 2014; Scott and Bowling 2015).
Key Points
• Feeding is an essential part of being human andinfluenced by cultural, ethical, religious, andsocietal beliefs. Weight loss, malnutrition, andthe inability to feed are visible signs of illness,
Table 7 Refeeding syndrome (National Institute for Health and Clinical Excellence 2006; Mehanna et al. 2008;Blumenstein et al. 2014; Scott and Bowling 2015)
Definition Potentially fatal shifts in fluids and electrolytes that may occur upon the reinstitution of oral,enteral, or parenteral nutrition in malnourished patients
High-risk patients Patients with
Anorexia nervosa
Chronic alcoholism
Malignancy
Postoperative patients
Poorly controlled DM
Chronic malnutrition
Patients receiving long term antacids and diuretics
Geriatric patients with multiple medical comorbidities and decreased functional reserves
Clinicalmanifestations
Hypophosphatemia (hallmark feature)
May present as cardiac arrhythmias, rhabdomyolysis, respiratory failure, cardiac failure,hypotension, seizure, coma, and sudden death
Thiamine deficiency
May present as Wernicke’s encephalopathy
Hypokalemia
May present as severe muscle weakness or rhabdomyolysis, cardiac arrhythmias, and EKGabnormalities
Hypomagnesemia
May present with cardiovascular (cardiac arrhythmias/EKG abnormalities) or neuromuscularmanifestations (of hyperexcitability [tremor, tetany, convulsions] or features of weakness,apathy, delirium, and coma)
Sodium and fluid imbalance
Resulting in fluid overload and exacerbation of congestive heart failure
Abnormalities in glucose, protein, and fat metabolism
Monitoring Measure
Serum phosphate, magnesium, calcium, potassium, urea, and creatinine concentrations beforefeeding and monitor regularly during the first week after feeding is initiated
Prevention andtreatment
Cornerstones for prevention and treatment are
Gradual introduction and
Slow advancement of feeding along with
Close monitoring of laboratory data
Supplementation of essential electrolytes
18 M. Kohli et al.
while normal food intake is associated withcomfort, pleasure, and good health.
• Early supplemental feeding intervention cancorrect malnutrition and promote quality oflife and longevity provided the underlying con-ditions are reversible.
• In circumstances where illness is irreversible orwhen older adults approach the end of life,artificial nutrition and hydration may place anundue burden, worsen the quality of life, andprolong the dying process.
• Dysphagia in older adults places a burden onboth patients and caregivers.
• Decision-making regarding alternatives to reg-ular oral intake such as tube feeding may bechallenging and distressing to the patient, care-giver, and healthcare proxy and involve ethicalconsiderations.
• A recommendation to pursue tube feedingneeds to take into consideration expected ben-efits, risks of the procedure, the burden of care,patient autonomy and principles of ethics, fam-ily preferences, the prognosis of the underlyingillness, and life expectancy.
• In advanced dementia, comfort feeding shouldbe promoted as opposed to tube feedings.
• Comfort feeding is associated with a betterquality of life; in addition, the approach helpsbetter address patient comfort and dignity.
• When the intent to initiate tube feeding in anolder adult is associated with limited benefit orsubstantial risk, particularly at the end of life,the decision to proceed with EN should not bebased on emotional distress surrounding theillness.
• Rather, the decision for long-term EN throughthe use of a PEG should be based on a realisticdiscussion of the benefits, harms, and alterna-tive options, without the promise of undueexpectations.
• Selection of specific foods and meals must bebased not only on the medical disorders of thepatient but also on traditions, lifestyles, andbeliefs; food equals health but also meanswell-being (Aguilera et al. 2019).
• Advance care planning and discussions aroundartificial nutrition and hydration and documen-tation of older adults’ preferences are useful inenabling sound decisions regarding EN, espe-cially when the patient lacks capacity and theproxy or caregiver is unable to participate indecision-making. Advance care planning insuch cases serves as a valuable guide to surro-gate decision-makers.
References
Achem SR, Devault KR. Dysphagia in aging. J ClinGastroenterol. 2005;39(5):357–71.
Aguilera JM, Kim B-K, Park DJ. Particular alimentationsfor nutrition, health and pleasure. Adv Food Nutr Res.2019;87:371–408.
Albanesi B, Marchetti A, D’Angelo D, et al. ExploringNurses' Involvement in Artificial Nutrition and Hydra-tion at the End of Life: A Scoping Review [publishedonline ahead of print, 2020 Feb 21]. JPEN J ParenterEnteral Nutr. 2020; https://doi.org/10.1002/jpen.1772.
Alkhawaja S, Martin C, Butler RJ, Gwadry-Sridhar F.Post-pyloric versus gastric tube feeding for preventingpneumonia and improving nutritional outcomes in crit-ically ill adults. Cochrane Database Syst Rev.2015;2015(8):Cd008875.
Allard JP, Keller H, Jeejeebhoy KN, Laporte M, DuerksenDR, Gramlich L, et al. Decline in nutritional status isassociated with prolonged length of stay in hospitalizedpatients admitted for 7 days or more: a prospectivecohort study. Clin Nutr. 2016;35(1):144–52.
American Gastroenterological Association Medical Posi-tion Statement. Guidelines for the use of enteral nutri-tion. Gastroenterology. 1995;108(4):1280–1.
American Geriatrics Society Ethics Committee and Clini-cal Practice and Models of Care Committee. AmericanGeriatrics Society feeding tubes in advanced dementiaposition statement. J Am Geriatr Soc. 2014;62(8):1590–3.
ArcandM. End-of-life issues in advanced dementia: part 1:goals of care, decision-making process, and familyeducation. Can Fam Physician. 2015a;61(4):330–4.
ArcandM. End-of-life issues in advanced dementia: part 2:management of poor nutritional intake, dehydration,and pneumonia. Can Fam Physician. 2015b;61(4):337–41.
Baiu I, Spain DA. Enteral nutrition. JAMA. 2019;321(20):2040.
Baniardalan M, Sabzghabaee AM, Jalali M, Badri S. Bac-terial safety of commercial and handmade enteral feedsin an Iranian teaching hospital. Int J Prev Med. 2014;5(5):604–10.
Enteral Nutrition 19
BaşkayaMK. Inadvertent intracranial placement of a naso-gastric tube in patients with head injuries. Surg Neurol.1999;52(4):426–7.
Blumenstein I, Shastri YM, Stein J. Gastroenteric tubefeeding: techniques, problems and solutions. World JGastroenterol. 2014;20(26):8505–24.
Bobo E. Reemergence of blenderized tube feedings. NutrClin Pract. 2016;31(6):730–5.
Bonten MJ, Gaillard CA, van der Hulst R, de Leeuw PW,van der Geest S, Stobberingh EE, et al. Intermittententeral feeding: the influence on respiratory and diges-tive tract colonization in mechanically ventilated inten-sive-care-unit patients. Am J Respir Crit Care Med.1996;154(2 Pt 1):394–9.
Bremner WG. Hypertensive response to passage of a naso-gastric tube. Anaesthesia. 1993;48(4):353.
Brousseau VJ, Kost KM. A rare but serious entity: naso-gastric tube syndrome. Otolaryngol Head Neck Surg.2006;135(5):677–9.
Brown B, Roehl K, Betz M. Enteral nutrition formulaselection. Nutr Clin Pract. 2015;30(1):72–85.
Buckler DA, Kelber ST, Goodwin JS. The use of dietaryrestrictions in malnourished nursing home patients. JAm Geriatr Soc. 1994;42(10):1100–2.
Carrillo E, Muoz J, Tortosa JA. Intrapleural placement of anasogastric tube. Can J Anaesth. 1998;45(3):284–5.
Cereda E, Pedrolli C, Klersy C, Bonardi C, Quarleri L,Cappello S, et al. Nutritional status in older personsaccording to healthcare setting: a systematic review andmeta-analysis of prevalence data using MNA®. ClinNutr. 2016;35(6):1282–90.
Chapman M, Peake SL, Bellomo R, Davies A, Deane A,Horowitz M, et al. Energy-dense versus routine enteralnutrition in the critically ill. N Engl J Med. 2018;379(19):1823–34.
Corrigan ML, Escuro AA, Celestin J, Kirby DF. Nutritionin the stroke patient. Nutr Clin Pract. 2011;26(3):242–52.
Culpepper JA, Veremakis C, Guntupalli KK, Sladen A.Malpositioned nasogastric tube causing pneumothoraxand bronchopleural fistula. Chest. 1982;81(3):389.
Cummings JR, Mason AE, Puterman E, Tomiyama AJ.Comfort eating and all-cause mortality in the US healthand retirement study. Int J Behav Med. 2018;25(4):473–8.
Desmond P, Raman R, Idikula J. Effect of nasogastric tubeson the nose and maxillary sinus. Crit Care Med.1991;19(4):509–11.
Escuro AA, Hummell AC. Enteral formulas in nutritionsupport practice. Nutr Clin Pract. 2016;31(6):709–22.
Ferreras J, Junquera LM, Garcia-Consuegra L. Intracranialplacement of a nasogastric tube after severe craniofa-cial trauma. Oral Surg Oral Med Oral Pathol OralRadiol Endod. 2000;90(5):564–6.
Geeganage C, Beavan J, Ellender S, Bath PM. Interven-tions for dysphagia and nutritional support in acute andsubacute stroke. Cochrane Database Syst Rev.2012;10:Cd000323.
Genu PR, de Oliveira DM, Vasconcellos RJ, Nogueira RV,Vasconcelos BC. Inadvertent intracranial placement ofa nasogastric tube in a patient with severe craniofacialtrauma: a case report. J Oral Maxillofac Surg. 2004;62(11):1435–8.
Gomes CA Jr, Andriolo RB, Bennett C, Lustosa SA,MatosD, Waisberg DR, et al. Percutaneous endoscopicgastrostomy versus nasogastric tube feeding for adultswith swallowing disturbances. Cochrane Database SystRev. 2015;22(5):Cd008096.
Gramlich L, Kichian K, Pinilla J, Rodych NJ, Dhaliwal R,Heyland DK. Does enteral nutrition compared to par-enteral nutrition result in better outcomes in critically illadult patients? A systematic review of the literature.Nutrition. 2004;20(10):843–8.
Griffith DP, McNally AT, Battey CH, Forte SS, CacciatoreAM, Szeszycki EE, et al. Intravenous erythromycinfacilitates bedside placement of postpyloric feedingtubes in critically ill adults: a double-blind, random-ized, placebo-controlled study. Crit Care Med. 2003;31(1):39–44.
Halloran O, Grecu B, Sinha A. Methods and complicationsof nasoenteral intubation. J Parenter Enter Nutr.2011;35(1):61–6.
Heintschel M, Heuberger R. The potential role of zincsupplementation on pressure injury healing in olderadults: a review of the literature. Wounds. 2017;29(2):56–61.
Heuschkel R, Duggan C. Enteral feeding: gastric versus post-pyloric. UptoDate [Internet]. 2019. Available from: https://www.uptodate.com/contents/enteral-feeding-gastric-versus-post-pyloric?source¼history_widget#H4. Cited 1Dec2019.
Heyland DK, MacDonald S, Keefe L, Drover JW. Totalparenteral nutrition in the critically ill patient: a meta-analysis. JAMA. 1998;280(23):2013–9.
Heyland DK, Dhaliwal R, Drover JW, Gramlich L, DodekP. Canadian clinical practice guidelines for nutritionsupport in mechanically ventilated, critically ill adultpatients. JPEN J Parenter Enteral Nutr. 2003;27(5):355–73.
Hoffer LJ, Bistrian BR, Driscoll DF. Enteral and parenteralnutrition. In: Jameson JL, Fauci AS, Kasper DL,Hauser SL, Longo DL, Loscalzo J, editors. Harrison’sprinciples of internal medicine. 20th ed. New York:McGraw-Hill Education; 2018.
Horowitz M, Maddern GJ, Chatterton BE, Collins PJ,Harding PE, Shearman DJ. Changes in gastric empty-ing rates with age. Clin Sci. 1984;67(2):213–8.
Ichimaru S. Methods of enteral nutrition administration incritically ill patients: continuous, cyclic, intermittent,and bolus feeding. Nutr Clin Pract. 2018;33(6):790–5.
Jaafar MH, Mahadeva S, Tan KM, Chin A-V,Kamaruzzaman SB, Khor HM, et al. Long-term naso-gastric versus percutaneous endoscopic gastrostomytube feeding in older Asians with dysphagia: a prag-matic study. Nutr Clin Pract. 2019;34(2):280–9.
20 M. Kohli et al.
Jeejeebhoy KN. Enteral nutrition versus parenteral nutri-tion – the risks and benefits. Nat Clin PractGastroenterol Hepatol. 2007;4(5):260–5.
Jensen GL, Cederholm T, Correia MITD, Gonzalez MC,Fukushima R, Higashiguchi T, et al. GLIM criteria forthe diagnosis of malnutrition: a consensus report fromthe global clinical nutrition community. J ParenterEnter Nutr. 2019;43(1):32–40.
Jiyong J, Tiancha H, Huiqin W, Jingfen J. Effect of gastricversus post-pyloric feeding on the incidence of pneu-monia in critically ill patients: observations from tradi-tional and Bayesian random-effects meta-analysis. ClinNutr. 2013;32(1):8–15.
Juneja M, O’Keefe S. Enteral and Parenteral Nutrition.2012:127–35.
Kamarul Zaman M, Chin KF, Rai V, Majid HA. Fiber andprebiotic supplementation in enteral nutrition: a sys-tematic review and meta-analysis. World JGastroenterol. 2015;21(17):5372–81.
Kirby DF, DeLegge MH, Fleming CR. American gastro-enterological association technical review on tube feed-ing for enteral nutrition. Gastroenterology. 1995;108(4):1282–301.
Koretz RL, Avenell A, Lipman TO, Braunschweig CL,Milne AC. Does enteral nutrition affect clinical out-come? A systematic review of the randomized trials.Am J Gastroenterol. 2007;102(2):412–29. Quiz 68.
Kritchevsky SB, Braun BI, Kusek L, Wong ES, SolomonSL, Parry MF, et al. The impact of hospital practice oncentral venous catheter-associated bloodstream infec-tion rates at the patient and unit level: a multicenterstudy. Am J Med Qual. 2008;23(1):24–38.
Lind LJ,Wallace DH. Submucosal passage of a nasogastrictube complicating attempted intubation during anesthe-sia. Anesthesiology. 1978;49(2):145–7.
Locher JL, Robinson CO, Roth DL, Ritchie CS, BurgioKL. The effect of the presence of others on caloricintake in homebound older adults. J Gerontol A BiolSci Med Sci. 2005;60(11):1475–8.
Luft VC, Beghetto MG, deMello ED, Polanczyk CA. Roleof enteral nutrition in the incidence of diarrhea amonghospitalized adult patients. Nutrition. 2008;24(6):528–35.
MacLeod JB, Lefton J, Houghton D, Roland C, Doherty J,Cohn SM, et al. Prospective randomized control trial ofintermittent versus continuous gastric feeds for criti-cally ill trauma patients. J Trauma. 2007;63(1):57–61.
Mandal NG, Foxell R. Knotting of a nasogastric tube.Anaesthesia. 2000;55(1):99.
McClave SA, Chang WK. Feeding the hypotensivepatient: does enteral feeding precipitate or protectagainst ischemic bowel? Nutr Clin Pract. 2003;18(4):279–84.
McClave SA, Lukan JK, Stefater JA, Lowen CC, LooneySW, Matheson PJ, et al. Poor validity of residual vol-umes as a marker for risk of aspiration in critically illpatients. Crit Care Med. 2005;33(2):324–30.
McClave SA, Taylor BE, Martindale RG, Warren MM,Johnson DR, Braunschweig C, et al. Guidelines for
the provision and assessment of nutrition support ther-apy in the adult critically ill patient. J Parenter EnterNutr. 2016;40(2):159–211.
McMahon MM, Nystrom E, Braunschweig C, Miles J,Compher C, the American Society for Parenteral andEnteral Nutrition (A.S.P.E.N.) Board of Directors. A.S.P.E.N. clinical guidelines: nutrition support of adultpatients with hyperglycemia. J Parenter Enter Nutr.2013;37(1):23–36.
Mehanna HM, Moledina J, Travis J. Refeeding syndrome:what it is, and how to prevent and treat it. BMJ.2008;336(7659):1495–8.
Mentec H, Dupont H, Bocchetti M, Cani P, Ponche F,Bleichner G. Upper digestive intolerance during enteralnutrition in critically ill patients: frequency, risk factors,and complications. Crit Care Med. 2001;29(10):1955–61.
Montecalvo MA, Steger KA, Farber HW, Smith BF,Dennis RC, Fitzpatrick GF, et al. Nutritional outcomeand pneumonia in critical care patients randomized togastric versus jejunal tube feedings. The Critical CareResearch Team. Crit Care Med. 1992;20(10):1377–87.
Montejo JC. Enteral nutrition-related gastrointestinal com-plications in critically ill patients: a multicenter study.The Nutritional and Metabolic Working Group of theSpanish Society of Intensive Care Medicine and Coro-nary Units. Crit Care Med. 1999;27(8):1447–53.
Montejo JC, Minambres E, Bordeje L, Mesejo A, Acosta J,Heras A, et al. Gastric residual volume during enteralnutrition in ICU patients: the REGANE study. Inten-sive Care Med. 2010;36(8):1386–93.
Morley JE, Kraenzle D. Causes of weight loss in a com-munity nursing home. J Am Geriatr Soc. 1994;42(6):583–5.
Naber TH, Schermer T, de Bree A, Nusteling K, Eggink L,Kruimel JW, et al. Prevalence of malnutrition in non-surgical hospitalized patients and its association withdisease complications. Am J Clin Nutr. 1997;66(5):1232–9.
Namasivayam-MacDonald AM, Shune SE. The burden ofdysphagia on family caregivers of the elderly: a sys-tematic review. Geriatrics. 2018;3(2):30.
Nathoo N, Nadvi SS. Intracranial malposition of a naso-gastric tube following repair of choanal atresia. Br JNeurosurg. 1999;13(4):409–10.
National Institute for Health and Clinical Excellence.Nutrition support for adults: oral nutrition support,enteral tube feeding and parenteral nutrition. Clinicalguideline CG32. London: NICE; 2006. Available from:https://www.nice.org.uk/guidance/cg32. Updated2017.
Ott DJ, Mattox HE, Gelfand DW, Chen MY, Wu WC.Enteral feeding tubes: placement by using fluoroscopyand endoscopy. AJR Am J Roentgenol. 1991;157(4):769–71.
Parker BA, Chapman IM. Food intake and ageing – the roleof the gut. Mech Ageing Dev. 2004;125(12):859–66.
Pash E. Enteral nutrition: options for short-term access.Nutr Clin Pract. 2018;33(2):170–6.
Enteral Nutrition 21
Petrov MS, Zagainov VE. Influence of enteral versus par-enteral nutrition on blood glucose control in acutepancreatitis: a systematic review. Clin Nutr. 2007;26(5):514–23.
Prabhakaran S, Doraiswamy VA, Nagaraja V, Cipolla J,Ofurum U, Evans DC, et al. Nasoenteric tube compli-cations. Scand J Surg. 2012;101(3):147–55.
Quain AM, Khardori NM. Nutrition in wound care man-agement: a comprehensive overview.Wounds. 2015;27(12):327–35.
Reignier J, Mercier E, Le Gouge A, Boulain T, Desachy A,Bellec F, et al. Effect of not monitoring residual gastricvolume on risk of ventilator-associated pneumonia inadults receiving mechanical ventilation and earlyenteral feeding: a randomized controlled trial. JAMA.2013;309(3):249–56.
Reintam Blaser A, Starkopf J, Alhazzani W, Berger MM,Casaer MP, Deane AM, et al. Early enteral nutrition incritically ill patients: ESICM clinical practice guide-lines. Intensive Care Med. 2017;43(3):380–98.
Rice TW, Wheeler AP, Thompson BT, Steingrub J, HiteRD, Moss M, et al. Initial trophic vs full enteral feedingin patients with acute lung injury: the EDEN random-ized trial. JAMA. 2012;307(8):795–803.
Ritchie C, Yukawa M. Geriatric nutrition: nutritional issues inolder adults. In: UptoDate [Internet]. 2019. Available from:https://www.uptodate.com/contents/geriatric-nutrition-nutritional-issues-in-older-adults?search¼malnutrition&source¼search_result&selectedTitle¼1~150&usage_type¼default&display_rank¼1. Cited 1 Dec 2019.
Rolls BJ. Do chemosensory changes influence food intakein the elderly? Physiol Behav. 1999;66(2):193–7.
Rushdi TA, Pichard C, Khater YH. Control of diarrhea byfiber-enriched diet in ICU patients on enteral nutrition:a prospective randomized controlled trial. Clin Nutr.2004;23(6):1344–52.
Scaife CL, Saffle JR, Morris SE. Intestinal obstructionsecondary to enteral feedings in burn trauma patients.J Trauma. 1999;47(5):859–63.
Schwartz DB. Enteral nutrition and dementia integratingethics. Nutr Clin Pract. 2018;33(3):377–87.
Scott R, Bowling TE. Enteral tube feeding in adults. J RColl Physicians Edinb. 2015;45(1):49–54.
Seres D. Nutrition support in critically ill patients: enteralnutrition. In: UptoDate [Internet]. 2019. Available from:https://www.uptodate.com/contents/nutrition-support-in-critically-ill-patients-enteral-nutrition?search¼enteral%20nutritlectedTitle¼1~150&usage_type¼default&display_rank¼1#H34. Cited 1 Dec 2019.
Seres D. Nutrition support in critically ill patients: parenteralnutrition. In: UptoDate [Internet]. 2020. Available from:https://www.uptodate.com/contents/nutrition-support-in-critically-ill-patients-parenteral-nutrition?source¼autocomplete&index¼0~2&search¼pare. Cited 5 Feb 2020.
Shi H, Lu JH, Wang SN, Na Q, Xu LF, Hong JA. Effect ofearly enteral nutrition in elderly patients with hip frac-ture during the perioperative period. J BackMusculoskelet Rehabil. 2020;33(1):109–17.
Slagt C, Innes R, Bihari D, Lawrence J, Shehabi Y. A novelmethod for insertion of post-pyloric feeding tubes at thebedside without endoscopic or fluoroscopic assistance:a prospective study. Intensive Care Med. 2004;30(1):103–7.
Sofferman RA, Haisch CE, Kirchner JA, Hardin NJ. Thenasogastric tube syndrome. Laryngoscope. 1990;100(9):962–8.
Sorokin R, Gottlieb JE. Enhancing patient safety duringfeeding-tube insertion: a review of more than 2,000insertions. JPEN J Parenter Enteral Nutr. 2006;30(5):440–5.
Souza JT, Ribeiro PW, de Paiva SAR, Tanni SE, MinicucciMF, Zornoff LAM, et al. Dysphagia and tube feedingafter stroke are associated with poorer functional andmortality outcomes. Clin Nutr. 2019;S0261–5614(19):33174–7.
Steevens EC, Lipscomb AF, Poole GV, Sacks GS. Com-parison of continuous vs intermittent nasogastricenteral feeding in trauma patients: perceptions andpractice. Nutr Clin Pract. 2002;17(2):118–22.
Sullivan MM, Sorreda-Esguerra P, Platon MB, Castro CG,Chou NR, Shott S, et al. Nutritional analysis ofblenderized enteral diets in the Philippines. Asia Pac JClin Nutr. 2004;13(4):385–91.
Tappenden KA, Quatrara B, Parkhurst ML, Malone AM,Fanjiang G, Ziegler TR. Critical role of nutrition inimproving quality of care: an interdisciplinary call toaction to address adult hospital malnutrition. J AcadNutr Diet. 2013;113(9):1219–37.
Taylor SJ, Manara AR, Brown J. Treating delayed gastricemptying in critical illness: metoclopramide, erythro-mycin, and bedside (cortrak) nasointestinal tube place-ment. JPEN J Parenter Enteral Nutr. 2010;34(3):289–94.
Thompson MP, Morris LK. Unexplained weight loss in theambulatory elderly. J AmGeriatr Soc. 1991;39(5):497–500.
Ticinesi A, Nouvenne A, Lauretani F, Prati B, CerundoloN, Maggio M, et al. Survival in older adults withdementia and eating problems: to PEG or not to PEG?Clin Nutr. 2016;35(6):1512–6.
Torrington KG, Bowman MA. Fatal hydrothorax andempyema complicating a malpositioned nasogastrictube. Chest. 1981;79(2):240–2.
Valentine RJ, Turner WW Jr, Borman KR, Weigelt JA.Does nasoenteral feeding afford adequate gastroduode-nal stress prophylaxis? Crit Care Med. 1986;14(7):599–601.
Volicer L. Goals of care in advanced dementia: quality oflife, dignity and comfort. J Nutr Health Aging. 2007;11(6):481.
Volkert D, Berner YN, Berry E, Cederholm T, CotiBertrand P, Milne A, et al. ESPEN guidelines on enteralnutrition: geriatrics. Clin Nutr. 2006;25(2):330–60.
Wallace JI, Schwartz RS, LaCroix AZ, Uhlmann RF,Pearlman RA. Involuntary weight loss in older outpa-tients: incidence and clinical significance. J Am GeriatrSoc. 1995;43(4):329–37.
22 M. Kohli et al.
Weinberg L, Skewes D. Pneumothorax from intrapleuralplacement of a nasogastric tube. Anaesth IntensiveCare. 2006;34(2):276–9.
White JV, Guenter P, Jensen G, Malone A, Schofield M,Group AMW, et al. Consensus statement: Academy ofNutrition and Dietetics and American Society for Par-enteral and Enteral Nutrition. J Parenter Enter Nutr.2012;36(3):275–83.
Wilson M-MG, Vaswani S, Liu D, Morley JE, Miller DK.Prevalence and causes of undernutrition in medicaloutpatients. Am J Med. 1998;104(1):56–63.
Zaloga GP. Parenteral nutrition in adult inpatients withfunctioning gastrointestinal tracts: assessment of out-comes. Lancet. 2006;367(9516):1101–11.
Zaninotto G, Bonavina L, Pianalto S, Fassina A, Ancona E.Esophageal strictures following nasogastric intubation.Int Surg. 1986;71(2):100–3.
Enteral Nutrition 23
