College Answer

Overview:       Is it machine, tubing or patient?

a)         Use 100% O2 with manual bag ventilation to exclude ventilator problem. If he ventilates, it’s a Ventilator problem.  Change/fix ventilator.

b)         Put a suction catheter down the endotracheal tube. If it passes easily, it is not a tube problem (kinked in mouth, bitten, blocked with blood/secretions from poor humidification). Ability to pass a suction catheter does not exclude a cuff prolapse or ball valve obstruction. If the catheter can’t be passed, quickly change it. If in doubt, consider a bronchoscopy

c)         If it is not the ventilator or the tube, it’s the patient! Look for causes (pneumothorax, bronchospasm) and treat appropriately.

Discussion

A lot of the college questions have this pattern of "Mr so-and-so is impossible to ventilate - what will you do?".

A structured stereotypical approach is expected.

• Troubleshooting the circuit:
  • disconnect the patient from the ventilator, and manually bag the patient with 100% FiO2
  • If the lung compliance is good, the patient's ventilator or its tubing is the problem, and you can keep bagging the patient until the ventilator is changed.
  • if the bag ventilation is difficult, one must conclude that the patient is the problem.
• Troubleshooting the patient:
  • • Airway:
      • suction the patient, removing sputum plugs and clearing the ETT.
      • if the suction catheter cannot pass easily, the ETT may be blocked. Is there a cuff  herneation?
        • check whether the patient is chewing on it. Paralyse them if this is the case.
      • Auscultate the chest, ensuring the ETT is not in the right main bronchus
    • Breathing:
      • Auscultate the chest and perform a CXR looking for pneumothorax
      • Look for bronchospasm and features of anaphylaxis
      • The CXR will also reveal pleural effusions, hemothoraces and mucus-plugged atelectasis
      • Consider bronchoscopy to relieve the mechanical obstruction.