Safety and efficacy of the Tao facemask for positive pressure ventilation in morbidly obese patients

Abstract

Purpose: Positive-pressure mask ventilation is an essential skill for individuals providing basic and advanced airway interventions in a variety of clinical settings. The C-E grip technique is most commonly used with standard facemasks to provide an effective seal that allows for positive pressure ventilation. The Tao mask is a novel facemask that utilises an ergonomic grip by using downwards pressure of the palm of the hand accompanied by midline jaw lift. Specifically, the technique to create a seal involves downwards pressure of the palm centred on the mask accompanied by a jaw lift with four fingers centred under the mandible. A previous comparison between the Tao and standard masks revealed superior performance across a cross-section of average patients. The purpose of this study was to evaluate the safety and effectiveness of the Tao mask compared to the standard mask in a subset of patients with morbid obesity as defined by a body mass index (BMI) greater than or equal to 40 kg/m2. Methods: This prospective crossover trial included 156 patients aged ⩾18 years at the Medical University of South Carolina who were scheduled for elective surgery under general endotracheal anaesthesia with a BMI of ⩾40 kg/m2 at the time of surgery. After the induction of general anaesthesia, but prior to the administration of a neuromuscular blocking drug (NMBD), each patient was ventilated with both the standard and Tao masks, and effectiveness was measured using both the Han and Warters scales. The process was repeated after the administration of an NMBD. Results: Data were collected and analysed from 153 individuals. The mean BMI was 50.7 ± 9.3 kg/m2. The Tao mask ventilation scores were significantly lower (more effective) than the standard mask scores on both the Han and Warters Scales before pre-NMBD ( p = 0.0002 and p < 0.001, respectively) and after post-NMBD ( p = 0.002 and p < 0.001, respectively). On the Warters Scale, it was significantly easier to ventilate with the Tao Mask pre-NMBD ( p = 0.0001). On the Han Scale, the Tao mask was significantly easier than the standard mask post-NMBD ( p = 0.03). With regard to mask sequence, the mean Warters scores were lower for the Tao mask pre-NMBD only when the standard mask was used first ( p = 0.002). Similarly, the difference in the mean Warters scores post-NBMD was significant only when the standard mask was used first ( p = 0.02). Conclusion: The Tao mask demonstrated equivalent safety and superior effectiveness in ventilating morbidly obese surgical patients despite a trial design that favoured the standard mask owing to anaesthetist experience. The use of the Tao mask may be particularly beneficial in clinical situations involving inexperienced operators or in patients for whom mask ventilation is likely to be difficult. ClinicalTrials.gov registration number: NCT03473366