CICM SAQ 2015.1 Q12

This is an emergency situation with the risks of hypoxia, hypoventilation and/or barotrauma.

Management consists of concurrent resuscitation and focussed assessment to identify the underlying cause with definitive management as indicated.

The differential diagnosis includes:

• Ventilator malfunction
• Obstruction/kinking of circuit including filter
• Displacement/blockage trache tube
• Increased airway resistance e.g. bronchospasm
• Decreased lung or chest wall compliance e.g. pneumothorax, lung collapse, intra-abdominal hypertension

Stepwise response (does not have to be in this order)

• Increase FiO2 to 1.0
• Assess patient for severity of insult – is there haemodynamic instability? Is the patient peri-arrest?
• Call for help and crash trolley / difficult airway trolley if indicated
• Disconnect patient from the ventilator and manually ventilate with FiO2 1.0 and assess resistance/compliance
• If resistance/compliance seems normal with reduction in airway pressures and improvement in saturations 
then cause is due to ventilator malfunction or inappropriate settings. Replace ventilator and/or review settings
• If resistance/compliance seems abnormal then systematic approach to look for cause
• Check circuit and filter for kinking/blockage and unkink/replace as indicated
• Assess trache for position and patency – remove inner cannula and pass suction catheter. If not patent and 
not cleared by suction or if displaced (may be evidence of subcutaneous emphysema) remove trache tube, occlude stoma and ventilate initially with bag-valve-mask and subsequently re-intubate with oral endotracheal tube
• If trache tube patent and correctly placed assess chest expansion and air entry to confirm/exclude bronchospasm, pneumothorax, lobar collapse, pleural effusion etc.
• Treat as appropriate – bronchodilators, thoracocentesis, physio, bronchoscopy, pleural drainage
• If decreased chest wall compliance consider sedation
• If increased intra-abdominal pressure, treat appropriately e.g. gastric decompression
• Re-assess patient after definitive management with investigations as indicated e.g. ABG and CXR.
• Review 
ventilator settings
• Be aware there may be more than one cause.
 If there is an obvious precipitating cause e.g. pneumothorax complicating difficult CVC insertion, tracheostomy displacement then treat this directly but then re-assess patient for resolution of hypoxia and high airway pressures