Search

Abstract&#xD;Objective: Abnormal regional lung ventilation can lead to undesirable outcomes during the induction of anesthesia. Head rotated ventilation has proven to change the airflow of upper airway tract and be effective in increasing the tidal volume. This study aimed to investigate the influence of head rotated mask ventilation on regional ventilation distribution during the induction phase of anesthesia.&#xD;Approach: Ninety patients undergoing anesthesia induction were randomly assigned to receive either neutral head (neutral-head group) or rotated right side head (rotated-head group) mask ventilation. Pressure-controlled mode was used in all mechanical ventilation. The regional lung ventilation was monitored by electrical impedance tomography (EIT). The primary outcome was the ratio of left/right lung ventilation distribution. The secondary outcomes were GI, centre of ventilation (CoV,100%=entirely dorsal), regional ventilation delays standard deviation (RVDSD), and the regional lung distribution differences between spontaneous and mask ventilation.&#xD;Main results: Forty-two patients with neutral-head and 38 with rotated-head mask ventilation were analyzed finally. Compared with spontaneous ventilation, mask positive-pressure ventilation caused significant changes in the ratio of left/right lung ventilation distribution[0.85(0.27) versus 0.94(0.30);P=0.022]. However, there were no differences in the ratio of left/right lung ventilation distribution between neutral and rotated head groups (P=0.128). When compared with spontaneous ventilation, mask ventilation caused regional distributions of ventilation shifts towards ventral lung areas (CoV: 45.8%±5.1% versus 39.9%± 5.1%; P<0.001), significant lung ventilation inhomogeneity (GI: 0.41±0.08 versus 0.50±0.15; P<0.001), and decreased RVDSD (7.6±2.6 versus 5.2±3.0; P<0.001). Compared with neutral-head mask ventilation, rotated-head mask ventilation was associated with higher TVe (575.1 ml ± 148.6 ml versus 654.2 ml ± 204.0 ml; P = 0.049).&#xD;Significance: Mask positive ventilation caused regional lung ventilation changes. When compared with neutral-head mask ventilation, rotated-head mask ventilation did not improve the regional ventilation towards to left lung. However, rotated-head mask ventilation was associated with higher TVe.&#xD., (Creative Commons Attribution license.)