Endoscopic Sedation in the Bariatric Patient: Skating on Thin Ice?

Obesity remains a significant health problem in the USA. Slightly over a third of adults over the age of 20 are obese (BMI [ 30 kg/m) [1] and 5.7 % are classified as extremely obese with a BMI [ 40 kg/m [2]. In this issue of Digestive Diseases and Sciences, Jirapinyo et al. [3] provide more insight into an area of gastrointestinal endoscopy that remains sparsely populated with safety and efficacy data, namely endoscopist-directed sedation in obese subjects. The authors provide data on 1,385 consecutive upper endoscopic procedures for which moderate sedation was given, reporting an overall incidence of unplanned events of 1.6 %, with 0.6 % cardiopulmonary adverse events (CAEs) and 0.7 % requiring early termination of the procedure. Interpretation of studies of this nature is dependent on the authors’ definition of a cardiopulmonary adverse event. In the discussed study, the definitions included systolic hypotension with a value less than 90 mm Hg, cardiac arrhythmia (heart rate[120 or\60 beats per minute requiring treatment or premature termination of the procedure), or significant hypoxemia requiring temporary removal of the endoscope. Although the definition of hypotension is standard and widely accepted, the heart rate definition allows a degree of ‘‘subjectivity creep.’’ The defined endpoints for treatment and premature termination of the procedure may not have been uniform. For example, with the ‘‘significant hypoxemia’’ outcome, there were no established thresholds for the depth and duration of the event. Since the authors were not able to capture transient hypoxic episodes not requiring endoscope withdrawal, the true prevalence of CAEs was likely underreported. Clearly, the use of a unified CAE taxonomy would help bring order and uniformity to the reporting of safety outcomes for procedural sedation [4]. The Clinical Outcomes Research Initiative (CORI) database has provided a glimpse into immediate adverse events requiring an unplanned intervention. In an analysis including 1,590,648 procedures of which 543,950 were upper endoscopies, increasing American Society of Anesthesiologists (ASA) physical classification was associated with a higher prevalence of unplanned events [5]. The overall prevalence for unplanned events during upper endoscopy was 0.33 % utilizing the CORI database, compared with 1.6 % in the discussed study, which is 4.8 times higher. Of course, the types and definitions of the outcomes were different in both studies, but the difference in prevalence should give one pause. In an earlier study utilizing CORI, Sharma et al. [6] reported a host of independent risk factors for cardiopulmonary unplanned events. In addition to increasing with ASA classification ascendancy, other risk factors included inpatient procedures, non-university endoscopy sites, use of supplemental oxygen, and trainee involvement. Unfortunately, neither CORI study was able to address BMI as a potential risk factor. Obesity is a risk factor for sedation-related complications for anesthesia-assisted advanced endoscopic procedures such as endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography. Wani et al. [7], in a study of 1,016 patients undergoing advanced endoscopic procedures, reported that age, BMI dichotomized as \30 versus C30, and an ASA physical classification C3 were independent risk factors for sedation-related complications. J. Vargo (&) Department of Gastroenterology and Hepatology, Digestive Disease Institute, Cleveland Clinic, Cleveland, OH 44195, USA e-mail: vargoj@ccf.org