© Springer International Publishing Switzerland 2017Andrew Loveitt, Margaret M. Martin and Marc A. Neff (eds.)Passing the Certified Bariatric Nurses Exam10.1007/978-3-319-41703-5_11
11. Anesthesia in the Bariatric Patient
Department of General Surgery, Rowan University, Stratford, NJ, USA
Successful surgical management of obesity requires the appropriate utilization of anesthesia; derived from the Greek roots an for without and aisthēsis for sensation. Modern surgical techniques and advances have been the direct result of anesthetic technology. Prior to the advent of the sedative, relaxing, and amnesic capacities offered, operations were limited by patient tolerance and as such had considerably higher rates of failure and complication.
As with any special population, there are challenges that come with anesthesia when applied to the bariatric patient. Due to the variation in anatomy in obese patients, attention must be directed in particular to the cardiopulmonary system. Airway management specifically is a challenge that must be adequately evaluated in the preoperative setting. Increased soft tissue in the upper thorax and neck results in limitations in movement at the atlantoaxial joint and cervical spine. Further, there are increased folds in pharyngeal soft tissue. As such, challenges should be anticipated, and having advanced airway tools such as fiber optic laryngoscopes available will alleviate such issues. The anatomical contribution extends to ventilation, with increased work of breathing due to soft tissue stresses on the chest wall.
Drug metabolism is also affected by obesity. There is an increased volume of distribution because of greater body weight, and as such loading and maintenance doses must be recalculated by the anesthesia and surgical team.
Preoperative risk assessment should take into consideration the existence of comorbidities that could be addressed, as well as experiences with previous surgery and intubation. The size of the neck diameter is a predictor of intubation difficulty . Routine laboratory testing should include polysomnography, in order to institute continuous positive airway pressure in patients previously undiagnosed with obstructive sleep apnea.
The mechanical factors present in the preoperative arena are also to be addressed in the operating room. This includes positioning for both operative ease and induction of anesthesia. Allowing adequate access to the neck and head will greatly increase the likelihood of uncomplicated intubation. Further care should be taken to address pressure points that are subject to shear stress from the extended periods on the operating table. Establishing peripheral intravenous access in the obese patient carries its own challenges and should be anticipated and accounted for in the perioperative period. Intraoperatively, ventilation, intra-abdominal pressures, and vital signs should be closely monitored as with any surgery, but here too, there are particular nuances that are affected by body mass.
Post-procedure care is merely an extension of preoperative management. Pain control, thromboembolism prophylaxis, and encouragement of breathing exercise are mainstays of appropriate management . Obese patients are especially prone to hypercoagulability, and active measures to mitigate this risk should be instituted immediately . Pharmacologic control of nausea, with prevention of emesis, is exceptionally critical as it will protect the postsurgical abdomen from the shear stress of retching.