Ventilation

Question 1

Why do patients fail to wean?

Answer 1

Resp - increased WOB, increased resistance, reduced compliance, increased ventilatory requirements (e.g. acidosis)
Cardiac - IHD, valve disease, systolic or diastolic dysfunction
Neuromuscular - depressed central drive, neuromuscular pathology, critical illness polyneuropathy, electrolyte abnormalities, hypothyroid, anxiety, depression, delirium
Nutrition - anaemia, malnutrition, obesity

Question 2

How do you assess readiness to wean?

Answer 2

1. reason for intubation has resolved?
2. minimal secretion
3. good cough
4. cooperatvie
   PaO2/FiO2 > 200, fio2 < 0.5, pH > 7.25, PEEP < 10