Weaning From Ventilatory Support

Question 1

Describe weaning criteria

Answer 1

Medical stability (CXR, inflammatory markers)
Resolution of underlying problem
Adequate spontaneous respiratory effort
Patient understands and follows commands
Minimal secretions
pH and BE near norms

Question 2

List factors that influence weaning

Answer 2

Energy supply / demand - catabolic state, O2 utilisation is inhibited by sepsis and low Hb. Increased Raw - secretions, bronchoconstruction, poor compliance, poor nutrition

Neuromuscular competence (drive, weakness - disuse or critical illness weakness)

Question 3

Describe methods of weaning from ventilatory support

Answer 3

Step down assistance (work down to CPAP)
T-Piece (increased day time off support
NIV
Tracheostomy (decreased deadspace)

Question 4

Describe the role of the physio in weaning

Answer 4

Decrease Raw
Increase compliance
Optimise mm mechanics
Prevent peripheral deconditioning
Some evidence for RM training in neuromuscular disorders

Question 5

Describe criteria for extubation

Answer 5

Absent respiratory distress
No ventilatory support for 24hrs other than oxygen
Stable clinically
Able to protect airway (swallowing, gag reflex, effective cough)
Absence of delirium

Question 6

Describe why patients may fail to wean

Answer 6

Mismatch of ventilatory needs and neuromuscular capacity
Cardiovascular dysfunction - Left ventricular failure with acute pulmonary oedema
Stealing theory - other organs might fail if support is taken away