From the Guidelines
To emerge obese patients from general anesthesia, a careful and multi-step approach is crucial. This involves ensuring the patient is fully recovered from the anesthetic effects by verifying a stable vital sign profile, including a respiratory rate of 12-20 breaths per minute, oxygen saturation above 92% on room air, and a systolic blood pressure within 20% of pre-anesthetic values 1.
Key Strategies for Emergence
- Reversal of Neuromuscular Blockade: Administering a reversal agent such as neostigmine (0.05-0.1 mg/kg) and atropine (0.01-0.02 mg/kg) or glycopyrrolate (0.01-0.02 mg/kg) to reverse residual neuromuscular blockade, if applicable, guided by a nerve stimulator to restore motor capacity before waking the patient 1.
- Pain Management: Using a multimodal approach including acetaminophen (650-1000 mg every 4-6 hours) and opioids like fentanyl (25-50 mcg every 1-2 hours) or hydromorphone (0.2-0.5 mg every 2-4 hours), titrated to effect while closely monitoring respiratory status 1.
- Non-Opioid Analgesics: Considering the use of non-opioid analgesics such as ketamine (0.1-0.2 mg/kg every 1-2 hours) or lidocaine (1-2 mg/kg every 1-2 hours) to reduce opioid requirements 1.
- Extubation Criteria: Extubating the patient when they meet standard extubation criteria, including a strong cough, ability to follow commands, and adequate oxygenation and ventilation, and performing extubation with the patient awake and in the sitting position 1.
- Post-Extubation Monitoring: Closely monitoring the patient in a high-surveillance area, such as a post-anesthesia care unit, for at least 30 minutes to ensure a smooth recovery 1.
Additional Considerations
- For patients with confirmed Obstructive Sleep Apnea (OSA), the insertion of a nasopharyngeal airway before waking can help mitigate partial airway obstruction commonly seen during emergence from anesthesia 1.
- Maintaining the head-up position throughout recovery and monitoring of oxygen saturations until mobile postoperatively are also recommended strategies 1.
By following these guidelines and considering the individual patient's needs and conditions, healthcare providers can ensure a safe and effective emergence from general anesthesia for obese patients.
From the Research
Strategies for Emerging Obese Patients from General Anesthesia
To emerge obese patients from general anesthesia safely, several strategies can be employed:
- Use of the shortest acting, least fat soluble agents to ensure rapid recovery to safe levels of alertness and mobility 2
- Implementation of difficult intubation protocols and the use of protective ventilation, such as low tidal volume and moderate positive end-expiratory pressure 3
- Morphine sparing and semi-seated positioning as much as possible to reduce the risk of postoperative complications 3
- Monitoring of neuromuscular blockers and the depth of anesthesia, especially when total intravenous anesthesia is used in association with neuromuscular blockers 3
- Appropriate prophylaxis against venous thromboembolism and early mobilisation to reduce postoperative complications 3, 4
- Postoperative monitoring and respiratory assistance in selected patients, as well as early mobilization and physiotherapy 4
Considerations for Anesthetic Drug Dosage
When emerging obese patients from general anesthesia, consideration should be given to the dosage of anesthetic drugs:
- The dosage of anesthetic drugs is usually based on the ideal body weight or the adjusted body weight and then titrated, except for succinylcholine that is dosed according to the total body weight 3
- Allometric scaling is being tested in the different pharmacokinetic/dynamic models used in target controlled infusion devices, with improved performance as a result 2
Preoperative Evaluation and Intraoperative Management
Preoperative evaluation and intraoperative management are crucial for the safe emergence of obese patients from general anesthesia:
- Preoperative OSA screening is crucial in the obese patient, as well as its specific management: use of continuous positive pre-, per- and postoperative pressure 3
- Intraoperative ventilation settings affect clinical outcome, but the optimal ventilation strategy is still to be determined 4
- Opioid-free regimens are being widely investigated to reduce the risk of postoperative complications 4