[Anesthesia in gastrointestinal endoscopy: peroral endoscopic myotomy]

Idiopathic achalasia is a motility disorder of the esophagus characterized by a dysfunction of the lower esophageal sphincter, which typically manifests as dysphagia. Peroral endoscopic myotomy (POEM) is an interventional endoscopic procedure for achalasia, which was introduced in 2010. Although results from randomized studies comparing short-term and long-term safety and efficacy are yet to be published, POEM is regarded to be less invasive than the standard treatment of achalasia (laparoscopic Heller myotomy). POEM is the first endoscopic procedure routinely performed with the patient under general anesthesia. During the preoperative assessment particular attention must be paid to the specific fasting intervals and the risk of aspiration during induction of anesthesia. For the purpose of temporary surgical access, the integrity of the esophageal wall is deliberately interrupted to create a long submucosal tunnel. As a result, unwanted fistulas can arise between the esophageal lumen, the mediastinum, the pleura or the intraperitoneal cavity. Endoscopically insufflated CO₂ may escape into these surrounding compartments with subsequent systemic CO₂ accumulation, capnomediastinum, tension capnoperitoneum or pneumothorax. As a result substantial cardiorespiratory instability can arise. Thus, the attending anesthesiologist must be familiar with these typical complications and with specific emergency measures, such as compensatory hyperventilation, percutaneous needle decompression and thoracic drainage. The POEM procedure is a therapeutic innovation and interdisciplinary challenge. However, anesthesia standards of care have not yet been specified. The aim of this review is therefore to outline some clinical recommendations for the daily clinical practice based on existing evidence.