Nutrition Therapy of the Critically Ill Patient with
Organ FailureChris A Johannes
INASPEN
Respiratory Failure
Function of lungs: Move oxygen from air to venous blood and move carbon dioxide (CO2) out
Important functional components of lung:
Drive mechanism Muscles of respiration Alveoli
Source: Hasse J. Nutrition and Organ Failure. In DNS. Sharpening Your Skills as a Nutrition Support Dietitian, 2003, p. 227
Acute Respiratory Failure
Type 1: hypoxic respiratory failure. Low PaO2 with low to normal PaCO2 (PaO2/PaCO2 = partial pressure exerted by
O2/CO2 dissolved in arterial plasma) Type 2: hypercapneic-hypoxic respiratory
failure. Low PaO2 with increased PaCO2
Acute Respiratory Distress Syndrome (ARDS)
PaO2:FiO2 ratio ≤ 200 (FiO2 = fraction of inspired oxygen, the %
concentration of oxygen entering the lungs, ventilator or a blood oxygenator)
Bilateral pulmonary infiltrates seen on X-ray PAW ≤ 15) mm/Hg
PAW = pulmonary artery wedge pressure; normal is ≤ 12 mm/Hg
Chronic Respiratory Failure
Asthma COPD Bronchiectasis Cystic Fibrosis Infiltrative disease of the lung Pulmonary hypertension
Treatment Goals for Respiratory Failure
Treat underlying condition Support physiologic function
Maintain tissue oxygen delivery Minimize pulmonary edema Give nutrition support Prevent/manage infection
Source: Hasse J. Nutrition and Organ Failure. In DNS. Sharpening Your Skills as a Nutrition Support Dietitian, 2003, p. 227
Mechanical Ventilation Modes
Assist control (AC) Intermittent mandatory ventilation Synchronized intermittent mandatory
ventilation
Mechanical Ventilation Settings CPAP: continuous positive airway pressure PEEP: positive end-expiratory pressure
PEEP: A method of ventilation in which airway pressure is maintained above atmospheric pressure at the end of exhalation by means of a mechanical impedance, usually a valve, within the circuit. Purpose is to increase volume of gas remaining in lungs after expiration to decrease shunting of blood through the lungs and improve gas exchange. PEEP is done in ARDS (acute respiratory failure syndrome) to allow reduction in the level of oxygen being given
PSV: pressure support ventilation HFV: high frequency ventilation
Nutrient Requirements in Pulmonary Failure
Calories: don’t overfeed when weaning to prevent increased CO2 production Provide 25-30 kcal/kg or resting energy expenditure
Protein: 1.5-2 g/kg Amino acids may increase ventilation, increase O2
consumption and ventilatory response to hypoxia and hypercapnea
Carbohydrate: <5 ,g/kg/min Overall calories more important than percent CHO
Fat: N3 FA may be anti-inflammatory and alter immune status in sepsis/ARDS
Respiratory Quotient (RQ)
RQ is the ratio of carbon dioxide produced to oxygen consumed; is an indicator of fuel utilization
Normal (physiologic) range is 0.5 to 1.5 High RQ in a ventilator patient may make it
difficult to wean the patient from the respirator
Respiratory Quotient Values for Various Fuel Substrates
Fat 0.7
Protein 0.8
Carbohydrate 1.0
Mixed Diet ~0.85
Alcohol 0.67
Underfed <0.8
Adequately fed 0.8-1.0
Overfed >1.0
Treatment Goals for Liver Failure
Identify and treat cause of liver failure (if reversible)
Control problems associated with liver failure Give nutrition support Prevent/treat infection
Nutrient Requirements for Liver Failure
Calories: caloric requirements affected by acuteness of disease, seriousness of injury, absorption, other organ failure, sepsis; 25-35 kcals/kg or REE
Protein: well nourished/low stress: .8 g/kg; malnourished/with metabolic stress: up to 1.5 g/kg
CHO: ~70% non-protein calories; in acute failure, may need continuous glucose infusion Chronic: may have diabetes/hypoglycemia requiring
controlled CHO and insulin; in septic pts hypoglycemia occurs in 50% of cirrhotics
FAT: 30% non-protein calories; MCT may be helpful with LCT malabsorption
Fat Soluble Vitamins: Causes of Deficiencies in Liver Failure
Vitamin A: steatorrhea, neomycin, cholestyramine, alcohol
Vitamin D: steatorrhea, glucocorticoids, cholestyramine
Vitamin E: steaorrhea, cholestyramine Vitamin K: steatorrhea, antibiotics,
cholestyramine
Source: Hasse J. Nutrition and Organ Failure. In DNS. Sharpening Your Skills as a Nutrition Support Dietitian, 2003, p. 227
Water Soluble Vitamins: Causes of Deficiencies in Liver Failure
B6: alcoholism B12: cannot exclude deficiency during active
liver inflammation, fatty liver, carcinoma; causes alcoholism, cholestyramine
Niacin: alcoholism Thiamin: alcoholism Folate:alcoholism
Source: Hasse J. Nutrition and Organ Failure. In DNS. Sharpening Your Skills as a Nutrition Support Dietitian, 2003, p. 227
Minerals: Causes of Deficiencies in Liver Failure
Zinc: diarrhea, diuretics, alcoholism Magnesium: alcoholism, diuretics Iron: chronic bleeding (hemochromatosis
causes overload) Potassium: affected by diuretics, anabolism,
insulin use, renal function Phosphorus: affected by alcoholism,
anabolism, renal function
Renal Failure: Functions of Kidney
Excrete waste Electrolyte balance Hormonal regulation Blood pressure regulation Glucose homeostatis
Causes of Acute Renal Failure
Acute Tubular Necrosis: nephrotoxins (radiologic contrasts) aminoglycosides, NSAIDS, cisplatin, ethylene glycol, ACE inhibitors. Presents with ↓ UO, ↑ BUN, ↑ Creatinine, ↓ HCO3, ↑ or normal K+, ↑ phos
Oliguric phase persists ~1-2 weeks followed by diuretic phase
Causes of Acute Renal Failure
Prerenal azotemia: most common cause of acute azotemia, secondary to volume depletion
Acute interstitial nephritis Atheromatous emboli Ureteral obstruction Intrarenal obstruction
Treatment Goals for Acute Renal Failure
Correct electrolytes Control acidosis Treat significant hyperphosphatemia Treat symptomatic anemia Initiate dialysis for hyperkalemia or acidosis not
controlled, fluid overload, ↑ in BUN>20 mg/dl/24 hours or BUN>100 mg/dl
Evaluate drugs for renal effect Avoid/treat infection
Continuous Renal Replacement Therapy (CRRT)
Blood filtered continuously by semi-permeable membrane
Arteriovenous uses patient’s own blood pressure Venovenous: pump-driven Lower extracorporeal blood volume (compared to
HD) so better tolerated by hemodynamically unstable patients
Types: hemofiltration (AVH, CAVH, SCUF), continuous hemodialysis (CAVHD, CVVHD) and continuous hemodiafiltration (CAVHDF or CVVHDF)
Nutrition Implications of ARF
ARF causes anorexia, nausea, vomiting, bleeding
ARF causes rapid nitrogen loss and lean body mass loss (hypercatabolism)
ARF causes ↑ gluconeogenesis with insulin resistance
Dialysis causes loss of amino acids and protein Uremia toxins cause impaired glucose
utilization and protein synthesis
Nutrient Requirements in ARF Calories: 25-45 kcals/kg dry weight or REE Protein: about 10-16 g amino acids lost per day with
CRRT ARF w/o HD (expected to resolve within a few days): .6-1
g pro/kg Acute HD: 1.2-1.4 g/kg; acute PD: 1.2-1.5 g/kg; CRRT:
1.5-2.5 g/kg CHO: ~60% total calories; limit to 5 mg/kg/min;
peripheral insulin resistance may limit CHO In CWHD(F) watch for CHO in dialysate or replacement
fluids Fat: 20-35% of total calories; lipid clearance may be
impaired
Vitamins in ARF
Vitamin A: elevated vitamin A levels are known to occur with RF
Vitamin B – prevent B6 deficiency by giving 10 mg pyridoxine hydrochloride/day
Folate and B6: supplement when homocysteine levels are high
Vitamin C: <200 mg/day to prevent ↑ oxalate Activated vitamin D Vitamin K: give Vitamin K especially to pts on
antibiotics that suppress gut production of K
Minerals in RF
↑ potassium, magnesium, and phos occur often due to ↓ renal clearance and ↑ protein catabolism
↓ potassium, mg and phos can occur with refeeding
CRRT pts can have ↓ K+, phos Mg deficiency can cause K+ deficiency
resistant to supplementation Vitamin C, copper, chromium lost with CVVH
Fluid in ARF
Depends on residual renal function, fluid and sodium status, other losses
Usually 500 mL/day + urine output Fluid replacement needs can be ↑ with CRRT
Multiple Organ Failure: SIRS Site of infection established and at least two of
the following are present—Body temperature >38° C or <36° C—Heart rate >90 beats/minute—Respiratory rate >20 breaths/min (tachypnea)
—PaCO2 <32 mm Hg (hyperventilation)—WBC count >12,000/mm3 or <4000/mm3
—Bandemia: presence of >10% bands (immature neutrophils) in the absence of chemotherapy-induced neutropenia and leukopenia
Nutrition/Metabolism Considerations
Determine priorities for medical and nutrition therapy 3-5 times higher catabolism Increased skeletal muscle proteolysis Shift of amino acids from periphery to viscera for
gluconeogenesis
Nutrient Needs in MODS
Calories: 35 kcal/kg or REE Protein: up to 1.5-2.0 g/kg Fat: 30% nonprotein calories; ↑ MCT if bile
salt deficient; N3 vs N6 Micronutrients: evaluate individually Fluid: based on fluid status
Source: Hasse J. Nutrition and Organ Failure. In DNS. Sharpening Your Skills as a Nutrition Support Dietitian, 2003
Feeding Route
EN usually preferred over PN; PN may worsen liver function
Intubation does not preclude aspiration EN not contraindicated with varices Patients with CRF often may have
gastroparesis; may need motility agent
Source: Hasse J. Nutrition and Organ Failure. In DNS. Sharpening Your Skills as a Nutrition Support Dietitian, 2003
Formula Selection
Concentrated formulas may be helpful with fluid restriction
Formulas restricted in phos and potassium may be helpful in pts with high phos and K+
Immune-enhancing formulas (controversial)
Source: Hasse J. Nutrition and Organ Failure. In DNS. Sharpening Your Skills as a Nutrition Support Dietitian, 2003
Conclusion
Critically ill patients with organ failure present special challenges to the nutrition care professional and medical team
Medical and nutritional goals must be prioritized in these complex patients