Local and Regional Anesthesia in the Obese Patients

Abstract

Obesity is the major epidemic of our generation, and anesthesiologists are confronted to manage obese patients and their associated comorbidities at an increasing rate. Regional anesthesia is an attractive option for obese individuals because it avoids the need for airway manipulation with general anesthesia and may reduce or eliminate the need for opioids and their associated side effects. However, obesity presents unique challenges to performing regional blocks and raises the risk of certain complications. Respiratory complications are a major consideration when anesthetizing an obese patient; sedation should be avoided if possible, and breathing function may be impaired by certain nerve blocks (e.g., local anesthetic spread to phrenic nerve following interscalene brachial plexus block). The pathophysiology associated with obesity such as obstructive sleep apnea and the metabolic syndrome places these patients at increased risk for perioperative complications. Central neuraxial blocks tend to be more complicated in obese individuals due to positioning difficulties, smaller target area (i.e., epidural space), dosing adjustments, intravascular puncture, and hemodynamic changes. The aim of this chapter is to provide the anesthesiologist with a practical approach to the problems associated with regional anesthesia in obese patients.