Learning objectives

• Differential diagnosis and management of increased airway pressure in a mechanically ventilated patient

Definition

• Airway pressures that exceed the safe limit for ventilation, typically <30 cm H2O plateau pressure, could make ventilation difficult or cause barotrauma
• Can be constantly elevated in a given patient due to underlying conditions or can increase suddenly due to a wide variety of causes

Signs and symptoms

• High plateau and peak airway pressures
• Distorted capnography
• Inadequate tidal volumes
• Hemodynamic instability

Differential diagnosis

“Man versus machine”

• Anesthesia machine
  • Machine malfunction
  • Kinked breathing circuit
  • Physical obstruction of the circuit, (water or an occluded filter)
  • Dislodgement, kinking, or obstruction of the endotracheal tube
  • Incorrectly positioned endotracheal tube
• Patient
  • Inadequate depth of anesthesia
  • Decrease in pulmonary compliance:
    • Fibrosis
    • Pneumothorax
    • Atelectasis
    • Pulmonary edema
  • Decrease in chest wall compliance
    • Obesity
    • Ascites
    • Abdominal distension
    • Kyphoscoliosis
    • Pharmacological (opiates, NMBDs)
  • Malignant hyperthermia
  • Broncho-, or laryngospasm (anesthesiologic emergency!)

Management

Suggested reading

• Gouel-Cheron A, Neukirch C, Kantor E, et al. Clinical reasoning in anaphylactic shock: addressing the challenges faced by anaesthesiologists in real time: A clinical review and management algorithms. Eur J Anaesthesiol. 2021;38(11):1158-1167.
• Woods BD, Sladen RN. Perioperative considerations for the patient with asthma and bronchospasm. Br J Anaesth. 2009;103 Suppl 1:i57-i65.