Comparison of effectiveness of two commonly used two-handed mask ventilation techniques on unconscious apnoeic obese adults

Abstract

Background. Mask ventilation and tracheal intubation are basic techniques for airway management and mutually inclusive rescue measures to restore ventilation. The aim of this study was to compare the effectiveness of mask ventilation between two commonly used techniques of two-handed mask ventilation in obese unconscious apnoeic adults. Methods. Eighty-one obese adults received mask ventilation after induction using C-E clamp and modified V-E clamp techniques in a randomized crossover manner. Mechanical ventilation was provided using a pressure-control mode, at a rate of 10 bpm, with an inspiratory-to-expiratory time ratio of 1:2 and a pre-set plateau airway pressure of 20cm H2O. The primary outcome was expired tidal volume. Results. The BMI for the subjects was 37 (SD 4.9) kgm-2. The failure rates for mask ventilation (tidal volume≤anatomical dead space) were 44% for the C-E technique and 0% for the V-E technique (P<0.001). Tidal volume was significantly lower for the C-E than the V-E technique [371 (SD 345) vs 720 (244) ml, P< 0.001]. The peak airway pressures were 21 (SD 1.5) cm H2O for the C-E technique and 21 (1.3) cm H2O for the V-E technique. Conclusions. Mask ventilation using the modified V-E technique is more effective than with the C-E technique in unconscious obese apnoeic adults. Subjects who fail ventilation with the C-E technique can be ventilated effectively with the V-E technique.