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