Perioperative management of the severely obese patient: a selective pathophysiological review

Obesity is widespread, yet it is often understood primarily as a disorder of body structure. This article provides anesthesiologists with a synopsis of recent research into the complex pathophysiology of obesity. It emphasizes the importance of this information for the perioperative planning and management of this patient group and for reviewing some of the major perioperative challenges.

Obesity is a multisystem chronic pro-inflammatory disorder associated with increased morbidity and mortality. Adipocytes are far more than storage vessels for lipids. They secrete a large number of physiologically active substances called adipokines that lead to inflammation, vascular and cardiac remodelling, airway inflammation, and altered microvascular flow patterns. They contribute to linked abnormalities, such as insulin resistance and the metabolic syndrome, and they attract and activate inflammatory cells such as macrophages. These changes can lead ultimately to organ dysfunction, especially cardiovascular and pulmonary issues. In the respiratory system, anesthesiologists should be familiar not just with screening tools for obstructive sleep apnea but also with obesity hypoventilation syndrome, which is less well appreciated and carries a significant outcome disadvantage. Perioperative management is challenging. It is centred around cardiorespiratory and metabolic optimization, minimizing adverse effects of both pain and systemic opioids, effective use of regional anesthesia, and an emphasis on mobilization and nutrition - given the prevalence of micronutrient deficiencies in the severely obese. There is a risk of incorrect drug dosing in obesity, which requires an understanding of the appropriate dosing weights for perioperative medications.

The literature clearly highlights the complexity of severe obesity as a multisystem disease, and anesthesiologists caring for these patients perioperatively must have a sound understanding of the changes in order to offer the highest quality care to these patients.