OPTIMISING STRATEGIES TO WEAN THE CHRONICALLY CRITICALLY ILL
PATIENT
Dr Khoo Tien Meng
ASMIC 2018
3 Questions
• What is chronic critical illness (CCI)?
• How do we “optimise” a CCI patient?
• (How) can we wean a CCI patient?
Girard & Rafin, 1985 : “The chronically critically ill,
to save or let die?”
• “Iatrogenic” – consequence of advances in ICU care
• Survive initial acute critical illness, but remain dependent on ICU therapy…… persistent organ dysfunction, neither dying nor recovering sufficiently
• 5-10% of ICU population & rapidly increasing worldwide
• Extremely high cost (US$35 billion), morbidity & mortality
Definitions
• Placement of tracheostomy for disease other than head, face, neck
• Specific period of ventilation = prolonged mechanical ventilation (PMV)
• Composite definition :
tracheostomy after 10 days to facilitate prolonged MV, in a pt not expected to die or be liberated from MV within next 72 hours
• Reality – transition from acute to CCI is gradual
Pathogenesis of CCI – Conceptual Model
Survival because of modern ICU treatment & life support
Mediated by risk factors & inflammatory response
ACUTE CRITICAL ILLNESS
CHRONIC CRITICAL ILLNESS
• Initial overwhelming insult
• Defenses unable to cope especially if risk factors
• Failure of inflammation to down-regulate
• Acquisition of hallmark descriptors of CCI
Common Diagnosis/Eti0logies
• Elderly
• Chronic lung disease/COPD (comorbidity or primary cause)
• Sepsis with MODS
• ARDS
• Trauma
• Cardiopulmonary disease
• Cardiac/abdominal surgery
“Severe acute condition over severe chronic disease(s)”
Clinical features : Chronic Critical Illness Syndrome
• Discreet syndrome with constellation of features
Nelson, et al. Chronic Critical Illness.
Optimising CCI patient for weaning
• No major interventional trials in CCI pts
• Data only from descriptive single center studies
• Clinicians rely on experience & extrapolation of evidence from studies in acute critical illness
• Current approach :
Systemic view of CCI
Broader multi-disciplinary approach
Address all major clinical issues
Identify and correct all barriers to weaning
Nutrition Support & Metabolic Control
• Address kwashiorkor-like malnourished state
• Loss of lean mass, hypo-oncotic, anasarca
• Resp muscles negatively affected by malnutrition :
– fatiguability
– decreased insp & exp muscle strength
– decreased endurance
– depletion of diaphragmatic muscle mass
• No RCT data specifically for CCI pt
Summary of recommendations from review articles on nutrition in CCI
• Goals of nutritional intervention :
– Maintain lean body mass
– Provide appropriate energy & protein intake to facilitate weaning
• EN in pts with functional GIT
• Try polymeric formula 1st
• Semi-elemental formula in intestinal dysfunction
• Indirect calorimetry not easily available & no improved outcomes vs predictive equations
Nutrition dosing
• Avoid over- & under-feeding
• 20-25 kcal/kg/day
• Protein :
compensate for catabolism, lean body mass loss, wound healing
initially 1.0 - 1.2g/kg/day
uptitrate to 1.2 – 1.5g/kg/day
higher amounts on case-by-case basis
clinical requirements, biochemical tolerance
• Continuous feed initially, bolus feed later
• Consider PEG/PEJ if prolonged feed (>30days)
• Treat hyperglycaemia with insulin
Brain Dysfunction in CCI
Brain Dysfunction in CCI
• Coma or delirium
• Variety of neurological insults
• Adverse long term outcomes
• New onset delirium/coma evaluation for etiology &/or risk factors
Coma imaging, EEG
Delirium search for modifiable risk factors eg. sepsis, hypoxia, electrolytes, exposure to sedatives
Brain Dysfunction in CCI
• Exposure to sedatives – Major risk factor
– Esp. benzodiazepines – avoid whenever possible
– Consider alternatives : opioids (think pain 1st)
propofol
dexmedetomidine
anti-psychotics
• Non-pharmacologic strategies for delirium – orientation - visual & hearing aids
– sleep protocols - physical therapy/mobilization
Physical Therapy (PT)
• Early mobilisation & PT
– established standard of care
– feasible & safe
– better outcomes
• PT in CCI pts
– Small studies with major limitations
– Findings consistently support benefits of whole body PT in CCI pts
– Integral part of management of ICU-acquired weakness
Immune Deficiency & Infection
• Risk factors :
indwelling catheters
skin breakdown
environment – MDR organisms thrive
“immune exhaustion”
malnutrition
comorbidities eg. DM, renal insufficiency
• Septic pt cannot be weaned!
Impairs defenses
Prevention!
• Strict infection control practices
– Prevention guidelines/protocols eg VAP, CRBSI
– Hand hygiene
– Whole body chlorhexidine baths
– Isolation/cohort pts with MDROs
• Antimicrobial stewardship
• Lancet Respir Med 2015
• Analyse long-term mortality & successful liberation from MV
• 124 studies, 16 countries, >300,000 pts with PMV
• 50% successfully liberated from MV
• Mortality at hospital discharge = 29%
• Only 19% discharged home
• Mortality at 1 year = 59%
Weaning Strategies
• Still a goal despite poor functional status & long term outcome : – improve QOL - allow phonation
– enhance mobility - reduce VAP
– sense of independence
• Placement of tracheostomy
• 2 steps : i. Identify & correct barriers to weaning
“all weaning efforts futile unless/until underlying causes of ventilator dependence reversed”
ii. Systematic protocol for weaning from ventilator
Identifying & Correcting Barriers
Respiratory
• Reduced compliance – VAP
– Pulmonary oedema
– ALI
• Airways disease esp COPD – Increased WOB
– DHI
– Auto-PEEP
Cardiovascular
• CHF/IHD
• SBTs may uncover cardiac dysfunction
• Management of myocardial ischaemia, fluid status, ventricular function, arrhythmias
• Echo + BNP help diagnose cardiac origin of weaning failure
Identifying & Correcting Barriers
• Impaired central drive – Cerebrovascular/neurosurgical
– Sedating medications
– Alkalosis
• Patient-ventilator dyssynchrony
• Electrolytes – Mg, PO4, K
• Tracheostomy tube malposition!
• Adrenal insufficiency & hypothyroidism
• Psychological – anxiety & depression (family important!)
Weaning Protocol
• Be alert to improvements in lung function & strength
• Progressive reduction in level of ventilator support eg. PS 10-15 cmH2O, PEEP < 8, FiO2 <0.5
• Screen for readiness to wean
• Perform SBT = trachemask / trach collar (“self-breathing trial”)
• Progressively increase duration of SBT
• Frequent reassessments!
CHEST 2001
• Specialized weaning center in long-term acute care facility
• Prospective cohort study with historical control
• New therapist-implemented weaning protocol
• 252 consecutive pts in 18 month period
• Median time to wean decreased from 29 days to 17 days
• Outcomes (% weaned, ventilator dependent, mortality) comparable, but significantly shorter weaning times
• Follow up study in 2007 determined best RSBI as < 100
Dedicated
Team Physicians,
nurses, physical therapist,
nutritionist, family
Nutrition Support EN route preferentially
Metabolic substrates without overfeeding
Treat hyperglycaemia with insulin
Optimise Cognition Minimise deliriogenic drugs
& use alternatives Screen for delirium Non-pharmacologic
startegies
Optimise Function Rehabilitative focus
Initiate physical therapy early
Nelson, et al. Concise Clinical Review – Chronic Critical Illness. Am J Resp Crit Care Medicine, 2010
Prevent Infection & Other Complications
Bundles/protocols Hand hygiene
Isolation/cohort Skin integrity
Liberation from Ventilator
Identify barriers Protocol-driven approach
to weaning
Integrate Palliative Care Treat distressing symptoms
Communicate care goals Support family
Discuss limitation of treatment
THANK YOU
Pathogenesis of CCI
• Pt continue to survive because of modern life support
“essentially an unnatural state, devoid of evolutionary precedent, enriched by iatrogenesis, and saturated with medical technology to prolong life in those who would otherwise perish”
• Persistent inflammation leads to hallmark features of CCI