Title:
[Effects of recruitment maneuver in prone position on hemodynamics in patients with severe pulmonary infection].

Abstract:
To evaluate effects of recruitment maneuver in prone position on hemodynamics in patients with severe pulmonary infection, based on the protective pulmonary ventilation strategy.
Ninety-seven cases with severe pulmonary infection admitted to intensive care unit (ICU) of Ganzhou City People's Hospital undergoing mechanical ventilation were involved. Volume controlled ventilation mode with small tidal volume (8 ml/kg) and positive end-expiratory pressure (PEEP) of 6 cm H(2)O [1 cm H(2)O = 0.098 kPa] was conducted. Each patient underwent recruitment maneuver in supine position and then in prone position [PEEP 20 cm H(2)O+pressure control (PC) 20 cm H(2)O]. Heart rate (HR), mean arterial pressure (MAP), pulse oxygen saturation [SpO(2)] and blood gas analysis data were recorded before and after recruitment maneuver in either position. A double-lumen venous catheter was inserted into internal jugular vein or subclavian vein, and a pulse index contour cardiac output (PiCCO) catheter was introduced into femoral artery. Cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI), intra-thoracic blood volume index (ITBVI), extra vascular lung water index (EVLWI), global end-diastolic volume index (GEDVI), global ejection fraction (GEF), stroke volume variation (SVV) and central vein pressure (CVP) were monitored.
(1) Compared with data before recruitment maneuver, there were no significant differences in HR and MAP after supine position and prone position recruitment maneuver, but significant differences in SpO(2) were found between before and after recruitment maneuver when patients' position was changed (supine position: 0.954 ± 0.032 vs. 0.917 ± 0.025, P < 0.05; prone position: 0.982 ± 0.028 vs. 0.936 ± 0.039, P < 0.05). SpO(2) was higher in prone position recruitment maneuver (P < 0.05). (2) Compared with data before recruitment maneuver, CI [L×min(-1)×m(-2)], SVI (ml/m(2)), GEDVI (ml/m(2)) and GEF were decreased significantly during recruitment maneuver (supine position: CI 3.2 ± 0.4 vs. 3.8 ± 0.6, SVI 32.4 ± 5.6 vs. 38.8 ± 6.5, GEDVI 689 ± 44 vs. 766 ± 32, GEF 0.267 ± 0.039 vs. 0.305 ± 0.056; prone position: CI 3.1 ± 0.5 vs. 3.6 ± 0.4, SVI 31.2 ± 5.8 vs. 37.3 ± 5.0, GEDVI 678 ± 41 vs. 758 ± 36, GEF 0.268 ± 0.040 vs. 0.288 ± 0.053, all P < 0.05), and CVP [cm H(2)O] and SVV were significantly increased [supine position: CVP 10.7 ± 1.5 vs. 8.2 ± 2.5, SVV (11.2 ± 3.3)% vs. (8.3 ± 4.7)%; prone position: CVP 10.3 ± 1.8 vs. 8.1 ± 2.5, SVV (12.7 ± 3.4)% vs. (9.1 ± 3.6)%, all P < 0.05], but they returned to the level of that before recruitment maneuver soon after termination of recruitment maneuver. There were no significant differences in SVRI, ITBVI and EVLWI between before and after recruitment maneuver in both positions. There were also no significant differences in above parameters between two positions.
Based on the lung protective ventilation strategy of small tidal volume with PEEP, oxygenation was improved and SpO(2) was increased significantly when prone position ventilation combined with lung recruitment method was used in severe pulmonary infection patients. The effect of recruitment maneuver during prone position on hemodynamics was slight, except a temporary decrease of SVI and GEF just during recruitment maneuver.