Weaning from ventilation: Hot Case

GENERAL APPROACH

• Brain
• Cough
• Nerves
• NMJ
• Respiratory Muscles
• Pleura
• Airways (large and small)
• Parenchymal
• Chest wall
• Ventilator asynchrony

Assess for:

• Resolution of primary illness
• Cardiac failure
• Respiratory failure (primary disease; VAP; clearing secretions)
• Abdominal distension/failure and nutrition
• Neurological failure (GCS, weakness)

Cases:

• chest trauma
• neuromuscular disorders
• prolonged critical illness

INTRODUCTION

CUBICLE

• inhalers
• ventilators
• sputum
• isolation (MDR Organisms)
• evidence of being in ICU a long time

INFUSIONS

• TPN
• inotropes (active medical problems)
• bronchodilators
• antibiotics (MDRO)
• IV IG (GBS, MG, vasculitis)
• may be few or no infusions: weaning difficulty main reason for continued ICU stay

VENTILATOR

• type of tracheostomy
• type of ventilation (NIV, invasive, spontaneous breaths)
• settings (FiO2, PEEP, RR, PS, IE ratio)
• assess weaning strategy (T piece, flow by, gentle weaning of pressure support or RR)
• RR <30 (good)
• unassisted TV (>325 mL or 5mL/kg = good)
• rapid shallow breathing index (f/VT <105 = good)
• vital capacity (>15mL/kg = good)
• MV (<15 L/min = good)
• maximum inspiratory pressure (-15cmH2O = good; 90-120 cmH20 is normal)

MONITOR

• oxygen saturation (A-a gradient)
• tachycardia
• fever (ongoing sepsis)

EQUIPMENT

• intercostals drains (number, bubbling, drainage)
• inhalers
• nebulisers
• steroids (corticosteroids, testosterone analogues)

QUESTION SPECIFIC EXAMINATION

• tracheostomy
• neurological -> consciousness
• hands -> head -> chest -> abdo -> feet -> back

-> cardiovascular -> respiratory -> abdominal (tolerating feeds, distension, diarrhoea)

• nutritional state

Questions

• trends (e.g. fever, fluid balance)
• last sedation or paralysis?
• physiotherapy frequency
• frequency of suctioning
• nature of tracheal aspirates
• tolerating feeds
• diarrhoea

RELEVANT INVESTIGATIONS

• CXR
• ABG
• microbiology

OPENING STATEMENT

• = Multi-factorial and list headings of causes -> clinical signs associated with list

DISCUSSION

• strategies used to wean from mechanical ventilation
• objective indices to predict difficult weaning
• role for early tracheostomy
• automated weaning modes

References and Links

LITFL

• CCC — Weaning from mechanical ventilation (Hot Case)
• CCC — Extubation assessment hot case
• CCC — Spontaneous Breathing Trial
• CCC — Weaning from mechanical ventilation
• CCC — Indices that predict difficulty weaning
• CCC — Timing of Tracheostomy

Textbooks

• Foote C, Steel L, Vidhani K, Lister B, MacPartlin M, Blackwell N. Examination Intensive Care Medicine (2nd Edition), Elsevier 2011