Outpatient ECG Monitoring

To determine the incidence and duration of ECG abnormalities in healthy adults during short duration outpatient surgery and their relationship to important clinical events. METHOD: In 381, ASA Class I, day surgery patients undergoing short surgical procedures the ECG was monitored prospectively for evidence of abnormalities. The attending anaesthetist administered the anaesthetic and made all clinical decisions while relying on routine monitors (ECG, oximeter, BP, capnometer, oxygen analyser, low pressure alarm and anaesthetic gas monitors). Intra-operative events of clinical significance (e.g., light anaesthesia, regurgitation, coughing, hypotension, arterial desaturation, hiccoughs etc), ECG abnormalities and their duration were documented. RESULTS: Electrocardiographic abnormalities were detected in 21% of patients as follows: sinus tachycardia (11%), artifacts (7%), premature atrial contractions (1.6%), lead disconnects (1%), sinus bradycardia (0.5%) and premature ventricular contractions (0.3%). All abnormalities resolved spontaneously within three minutes. Intra-operative incidents of consequence occurred in only 2.6%: light anaesthesia (5), arterial desaturation > 5% (2), hypotension (1), hiccough (1) and regurgitation (1). All incidents were detected clinically and by pulse oximetry. The ECG did not detect any of the incidents and was normal during the events. CONCLUSION: Routine ECG monitoring did not detect intra-operative incidents in healthy adults during short outpatient procedures. Detected ECG abnormalities were benign and resolved spontaneously within three minutes. Firm conclusions as to the safety implications of withdrawing ECG monitoring cannot be drawn from this study. Guidelines may need to be reviewed to determine whether ECG monitoring in such cases should be optional rather than mandatory.