Subinternship Surgery · Year 4 · from Subinternship Surgery
Case 3: Weaning from Mechanical Ventilation
Clinical Image
Source: Wikimedia Commons - Mechanical Ventilation - CC BY-SA 4.0
Case Presentation
A 62-year-old man has been mechanically ventilated for 6 days following a complicated Whipple procedure with post-operative bleeding requiring re-exploration. He has been off vasopressors for 48 hours and is on FiO2 35%, PEEP 5, with adequate oxygenation (SpO2 97%). Sedation has been weaned, and he is alert, following commands, and has a strong cough. The team performs daily screening for spontaneous breathing trial (SBT) readiness: adequate oxygenation (FiO2 less than 50%, PEEP less than or equal to 8) - yes; hemodynamically stable without vasopressors - yes; alert and following commands - yes; adequate cough and manageable secretions - yes. He meets criteria for SBT. The respiratory therapist places him on pressure support of 5 cm H2O and CPAP 5 (minimal support) for a 30-minute trial. He tolerates this well: respiratory rate 18 (less than 35), tidal volume adequate, no accessory muscle use, oxygen saturation stable at 96%, heart rate and blood pressure stable, no distress. He passes the SBT. Before extubation, the team assesses for cuff leak (present, suggesting low risk of post-extubation stridor), confirms he can protect his airway, and ensures reintubation supplies are at bedside. He is extubated successfully. Supplemental oxygen via nasal cannula is provided. He is monitored closely for 24 hours and does well without reintubation.
Key Learning Points
- Daily screening for SBT readiness: adequate oxygenation on low FiO2/PEEP, hemodynamic stability, adequate mental status, and manageable secretions
- Spontaneous breathing trial methods: T-piece (no support), low-level pressure support (5-8 cm H2O), or CPAP; 30-120 minute duration
- SBT success criteria: respiratory rate less than 35, stable vital signs, no distress, adequate tidal volume, stable oxygenation
- Coordinating spontaneous awakening trials (SAT) with SBT improves weaning outcomes; assess sedation needs before SBT