Purpose: An endoscopic bite block is a device to ensure that the patient's mouth remains wide open during endoscopic procedures. Wide opening of the mouth may facilitate the efficiency of one-handed mask ventilation. We evaluated the effect of an endoscopic bite block on mask ventilation among three ventilation techniques: one-handed ventilation, one-handed ventilation with an endoscopic bite block, and two-handed ventilation.
Methods: Fifty-nine anesthetized and paralyzed patients were included. After induction of anesthesia, one-handed ventilation, one-handed ventilation with an endoscopic bite block and two-handed ventilation were performed in a cross-over, randomized order. The primary outcome was the expiratory tidal volume (mL/kg of predicted body weight). Secondary outcomes included minute ventilation (L/min) and the incidence of inadequate mask ventilation or dead space ventilation.
Results: The expiratory tidal volume of one-handed ventilation with an endoscopic bite block was significantly improved when compared with that of one-handed ventilation (8.2 [6.8-10.2] mL/kg vs. 7.1 [4.5-9.0] mL/kg, respectively, difference = 1.1 mL/kg; 95% CI 0.8-2.4; P < 0.001), and was comparable to that of two-handed ventilation (8.9 [6.3-11.5] mL/kg; difference = 0.7 mL/kg; 95% CI - 0.7 to 1.5; P = 0.432). Minute ventilation was also significantly improved in one-handed ventilation with an endoscopic bite block compared with that in one-handed ventilation (7.4 [6.3-8.6] L/min vs. 6.7 [4.2-7.9] L/min, respectively, difference = 0.7 L/min; 95% CI 0.6-2.0; P < 0.001), and was comparable to that of two-handed ventilation (7.7 [6.5-9.5] L/min; difference = 0.3 L/min; 95% CI - 0.5 to 1.4; P = 0.390). The incidence of inadequate ventilation or dead space ventilation was not different among the ventilation techniques (P = 0.080).
Conclusion: The use of an endoscopic bite block improved one-handed mask ventilation, showing comparable efficacy with two-handed mask ventilation.
Keywords: Endoscopic bite block; Expiratory tidal volume; One-handed mask ventilation.