From the Guidelines
Patients with Obesity Hypoventilation Syndrome (OHS) are at a significantly higher risk for perioperative complications, including respiratory failure, and therefore require careful preoperative evaluation, optimization, and postoperative management to minimize these risks. The risks associated with surgery in patients with OHS are multifaceted, stemming from their baseline respiratory compromise, which includes chronic hypercapnia, reduced functional residual capacity, and increased sensitivity to respiratory depressants 1.
Preoperative Evaluation and Optimization
Preoperative evaluation should include pulmonary function tests, arterial blood gases, and sleep studies if not previously diagnosed. Optimization before elective surgery is crucial and typically involves CPAP or BiPAP therapy for at least 2-4 weeks to improve respiratory function. This approach is supported by guidelines that emphasize the importance of managing sleep-disordered breathing and hypoventilation in patients with OHS before undergoing surgery 1.
Intraoperative Management
During surgery, careful airway management with preparations for potential difficult intubation, positioning with head elevation to reduce abdominal pressure on the diaphragm, and meticulous monitoring of oxygenation and ventilation are essential. The choice of anesthetic technique, with a preference for regional anesthesia when possible, can help minimize the risks associated with general anesthesia in these patients.
Postoperative Care
Postoperatively, patients with OHS require close observation in a monitored setting. Early resumption of PAP therapy, judicious use of opioids, and early mobilization are critical components of their care. The use of non-invasive ventilation (NIV) or bi-level positive airway pressure (BiPAP) in the postoperative period should be considered liberally, especially in the presence of hypoxemia or signs of respiratory distress 1.
Risks and Complications
The increased risks in patients with OHS are due to their underlying respiratory condition, which can be exacerbated by anesthetics, opioids, and the surgical procedure itself. Early recognition and management of these risks can significantly reduce perioperative complications, including respiratory failure, prolonged mechanical ventilation, and cardiopulmonary events. Guidelines from reputable sources, such as the American Thoracic Society and the Enhanced Recovery After Surgery (ERAS) Society, provide recommendations for the perioperative care of patients with OHS, emphasizing the need for a multidisciplinary approach to minimize risks and improve outcomes 1.
Given the complexity and severity of OHS, it is crucial to prioritize morbidity, mortality, and quality of life when making decisions regarding surgical interventions. The most recent and highest quality evidence should guide clinical practice, ensuring that patients receive optimal care tailored to their specific needs and risk profile 1.
From the Research
Risks of Surgery in Patients with Obesity Hypoventilation Syndrome (OHS)
The risks of surgery in patients with OHS include:
- Difficult intubation and loss of airway 2
- Postoperative respiratory failure 2, 3, 4, 5, 6
- Worsening heart failure 2
- Pulmonary hypertensive crisis 2
- Opioid-induced respiratory depression (OIRD) 2
- Atelectasis and obstruction of the airways 3, 6
- Acute hypercapnic respiratory failure (AHRF) 5
- Post-extubation respiratory distress 6
Perioperative Management
Perioperative management of patients with OHS is crucial to minimize risks:
- Preoperative screening for OSA and OHS is essential 2, 4, 6
- Use of non-invasive ventilation (NIV) can help reduce perioperative complications 3, 5, 6
- Cautious selection of the type of anesthesia and use of apneic oxygenation with high-flow nasal cannula during laryngoscopy can help minimize adverse perioperative events 4
- Proper patient positioning, especially during intubation and extubation, multimodal analgesia, and cautious use of postoperative supplemental oxygen are recommended 4
- Monitoring of neuromuscular blocking and depth of anesthesia is necessary 6
- Appropriate prophylaxis against venous thromboembolic disease and early mobilization are recommended 6