• Blockage of ET tube (secretions, food, kinked tubing, patient biting on ET tube)
• Coughing
• Bronchospasm
• Lower airway obstruction
• Pulmonary edema
• Pneumothorax
• Ventilator/patient dyssynchrony

• Assess lung sounds.
• Suction airway for  secretions.
• Insert bite block or administer sedation per orders if patient is agitated or biting on ET tube.
• Assess breath sounds for increased consolidation, wheezing, and bronchospasm; treat as ordered.

• Air leak in ventilator circuit or in the ET tube cuff

• Locate leak in ventilator system.
• Check pilot balloon as an indicator of ET tube cuff failure.
• Replace tubing as needed, per policy.

• Low air exchange due to shallow breathing or too few respirations

• Check for disconnection or leak in the system.
• Assess patient for decreased respiratory effort; consider decreasing sedative dosage or increasing the set respiratory rate or tidal volume.

• Worsening of clinical condition
• Common causes of hypoxia:
  • Pulmonary edema
  • Pneumonia
  • Pneumothorax
  • Pulmonary embolus
  • Mucus plugging
  • Atelectasis
• Pulse oximeter malpositioned
• SpO₂ cable unplugged
• Connective tissue disorder, such as Raynaud’s disease or scleroderma
• Hypoperfusion, such as with vasopressor use or shock states

• Ensure ventilator oxygen supply is connected.
• Observe pulse oximeter waveform on the monitor.
• Ensure pulse oximeter is positioned correctly.
• Verify all cables are plugged in.
• Auscultate for presence of breath sounds, worsening adventitious sounds or respiratory distress. 
• Assess perfusion.

Apnea

• Breaths are not being taken by the patient or triggered on the ventilator

• Assess patient effort and SpO₂; immediately adjust ventilator settings if hypoxic.
• Check system for disconnections.

• Decrease in venous return to the heart due to positive pressure applied to the lungs.

• Assess for adequate volume status by checking heart rate, blood pressure, central venous pressure and urine output. 
• Assess patient for increasing autopeep, which can increase risk for cardiac tamponade.

• Positive pressure applied to lungs.
• Elevated mean airway pressures may rupture alveoli.

• Notify healthcare provider.
• Prepare patient for possible chest tube insertion.
• Avoid high pressure settings for patients with chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), or history of pneumothorax.

• Breaks in ventilator circuit.
• Decreased mobility.
• Impaired cough reflex.
• Aspiration of subglottic secretions

• Use aseptic technique.
• Provide frequent mouth care.
• Keep head of bed elevated 30 degrees.
• Consider use of subglottic secretion drainage endotracheal tube.
• Provide frequent mouth care.
• Support proper nutritional status.