McGRATH MAC video laryngoscope for insertion of a transoesophageal echocardiography probe: A randomised controlled trial

BACKGROUND: Transoesophageal echocardiography (TOE) probe insertion in anaesthetised patients can cause pharyngeal and oesophageal injuries. Kim et al. have shown that insertion assisted by a Macintosh laryngoscope can reduce such complications but it may sometimes be difficult to observe the passage of a TOE probe. The McGRATH MAC (McGRATH) has been shown to provide a better view of the glottis, piriform fossa and oesophageal inlet during tracheal intubation than the Macintosh. OBJECTIVE: We hypothesised that the McGRATH provided better visualisation of the oesophageal inlet and was useful as an aid to TOE probe placement, possibly reducing the incidence of pharyngeal injury related to insertion, compared with the Macintosh. DESIGN: A randomised controlled trial. SETTING: The study was conducted in a university hospital from February to December 2014. PATIENTS: One hundred patients undergoing elective surgery under intraoperative TOE monitoring were randomised to either a Macintosh group or a McGRATH group. INTERVENTIONS: Macintosh and McGRATH were used to visualise the passage of the TOE probe and guide its insertion. MAIN OUTCOME MEASURES: Visibility of the oesophageal inlet, the number of TOE insertion attempts and incidence of pharyngeal mucosal injury after the TOE probe had been removed were assessed. RESULTS: The percentage of patients in whom the oesophageal inlet was visible was higher in the McGRATH group (88%) than in the Macintosh group (41%) (P < 0.01). The number of TOE probe insertion attempts was significantly smaller in the McGRATH group than in the Macintosh group (P = 0.039). The incidence of pharyngeal mucosal injury was significantly smaller in the McGRATH group (4%) than in the Macintosh group (16%; P = 0.042). CONCLUSION: The McGRATH provided a better view of the oesophageal inlet and was useful as an aid to TOE probe placement, possibly reducing the incidence of pharyngeal injury related to its insertion. TRIAL REGISTRATION: University Hospital Medical Information Network in Japan (UMIN) 000012970.