Hypoxia and hypotension during endoscopy and colonoscopy.

Sixty-three patients undergoing oesophagogastroduodenoscopy (OGD) (n = 24) or proctosigmoidocolonoscopy (PSC) (n = 39) had continuous monitoring of arterial oxygen saturation (SaO2), pulse and mean blood pressure (BP). The degree of patient distress, duration, dose of sedative and details of the endoscope and operator were recorded. Marked hypotensive (greater than 40% fall in BP) and hypoxic (greater than 8% fall in SaO2) changes occurred in 13% and 17% of the overall group, respectively. There were no significant differences in fall in BP, SaO2 or pulse between the OGD and PSC groups. The dose of sedative was significantly related to the fall in SaO2 (P less than 0.001) but not to the fall in BP. The falls in both SaO2 and BP were related to the duration of the procedure (P less than 0.001, P = 0.03, respectively). There were no correlations between the degree of hypoxia or hypotension and the patient's age or previous medical history. Hypotension and hypoxia occur in both colonoscopy and OGD and are neither predictable nor usually recognizable clinically. Pulse oximetric and BP monitoring throughout gastrointestinal endoscopy are recommended for maximal safety.