Twirl the head for better ventilation
An obstruction of the upper airways is a common occurrence after induction of general anesthesia, and a major cause of difficult mask ventilation. The present American-Japanese randomized study offers a solution: rotate the patient’s head and thereby improve the efficiency of mask ventilation.
40 patients undergoing general anesthesia for elective surgery were included. Once apnea had set in following induction of general anesthesia, face mask ventilation was started with pressure controlled ventilation, at a peak inspiratory pressure of 15 cmH2O. Each patient was ventilated for three 1-min intervals with the head position alternated every minute: In group A, mask ventilation was performed with a neutral head position for 1 min, followed by an axial head position rotated 45° to the right for 1 min and then returned to the neutral position for another 1 min. For patients in group B, the sequence of head positioning was rotated → neutral → rotated.
The results showed that the mean expiratory tidal volume was significantly higher in the rotated head position than in the neutral position, namely 612.6 vs. 544.0 ml (difference 68.6 ml, P < 0.0001).
Compared with the neutral head position, a head rotation of 45° significantly increases the efficiency of mask ventilation in anesthetized apnoeic patients, conclude the authors.