From the Guidelines
Neuraxial anesthesia can be safely and effectively used in obese patients undergoing surgery, but requires careful consideration of technical challenges, dosing adjustments, and potential complications. When performing spinal or epidural anesthesia in obese patients, anesthesiologists should anticipate difficult landmark identification and potentially deeper distance to the epidural space, often requiring longer needles and ultrasound guidance for placement 1.
Key Considerations
- Medication dosing typically requires reduction, with local anesthetic doses generally decreased by 20-30% compared to non-obese patients due to reduced cerebrospinal fluid volume and epidural fat displacement.
- Positioning is crucial, with the sitting position often preferred over lateral decubitus to improve landmark identification.
- Respiratory monitoring is essential as obese patients are more prone to respiratory depression and desaturation, particularly with concurrent sedation.
- Obese patients also have higher risks of failed blocks, high spinal anesthesia, and post-dural puncture headache.
Benefits of Neuraxial Anesthesia
- Neuraxial techniques offer significant advantages for obese patients, including avoidance of difficult airway management, reduced opioid requirements, improved postoperative pain control, and earlier mobilization, which can decrease thromboembolic complications common in this population 1.
- Regional anaesthetic techniques have been demonstrated to be highly efficient in reducing opioid requirements, with options such as epidural analgesia, ultrasound-guided transversus abdominis plane block, and infiltration of local anesthetics like bupivacaine 1.
Recent Guidelines
- The most recent guidelines from 2022 recommend using multimodal, opioid-sparing analgesia approaches to improve postoperative recovery, with a focus on short-acting agents and minimal opioid use during the operation 1.
- These guidelines also suggest that anaesthesia induction should preferably be based on lean body weight to avoid hypotension, and that propofol is a suitable induction agent for patients with severe obesity 1. In summary, neuraxial anesthesia is a viable option for obese patients undergoing surgery, but it is crucial to carefully consider the technical challenges and potential complications, and to follow recent guidelines for perioperative care.
From the Research
Considerations for Neuraxial Anesthesia in Obese Patients
- Neuraxial techniques are the preferred anesthetic techniques for cesarean delivery in obese parturients, but can be technically challenging 2
- The risk of difficult intubation is increased in obese patients, making neuraxial anesthesia a safer option 2, 3
- An existing labor epidural catheter can be topped up for cesarean delivery, and a combined spinal epidural technique may be preferred over a single-shot spinal technique in obese parturients 2
- There is no need to reduce the dose of spinal bupivacaine in the obese parturient, but limited data is available for super obese parturients 2
Technical Challenges and Solutions
- Difficulty in achieving peripheral and neuraxial blockade in obese patients is reported, with an increased incidence of failed blocks compared to normal weight patients 3
- Successful peripheral and neuraxial blockade in obese patients requires an experienced anesthesiologist with knowledge of the unique physiologic and pharmacologic differences in obese patients 3
- Intraoperative patient positioning, such as the ramped position, and close monitoring of ventilation and hemodynamic status are crucial 2
Postoperative Care and Analgesia
- Adequate postoperative analgesia is essential to allow for early mobilization, and can be achieved using a multimodal regimen incorporating neuraxial morphine, nonsteroidal anti-inflammatory drugs, and acetaminophen 2
- Thromboprophylaxis is important in obese patients due to the increased risk of thromboembolic complications 2
- Close postoperative monitoring is necessary due to the increased risk of postoperative complications in morbidly obese patients 2, 4