Capnography Detection Using Nasal Cannula Is Superior to Modified Nasal Hood in an Open Airway System: A Randomized Controlled Trial

Abstract

The nasal cannula and modified nasal hood are methods used by oral and maxillofacial surgeons to detect expired carbon dioxide during procedural sedation in an open airway system. The purpose of this study was to compare the accuracy of the detection of expired carbon dioxide between the nasal cannula and modified nasal hood. The authors designed a parallel-group randomized controlled trial to compare the nasal cannula and modified nasal hood. Patients presenting to the authors' institution for outpatient oral and maxillofacial surgery (OMS) using intravenous deep sedation or general anesthesia were randomized to have capnography detection by the modified nasal hood or the nasal cannula. The primary outcome variable was the percentage of accurately captured breaths, as determined by the average number of capnography waveforms per auscultated breath using a precordial stethoscope. The 2 groups were compared using t test. Fifty patients were screened for enrollment in the study. Twenty-five patients were randomized to the nasal cannula group and 25 patients were randomized to the modified nasal hood group. The proportion of accurate waveforms, recorded as a percentage of total breaths, was 95.7±4.7% for the nasal cannula and 75.8±14.1% for the modified nasal hood (P<.0001). When used for capnography for procedural sedation in an open airway system for routine OMS, the nasal cannula accurately recorded more breaths than the modified nasal hood.