Effect of mechanical ventilation mode on intra-and postoperative blood loss in patients undergoing posterior lumbar interbody fusion surgery

Objective To investigate the effect mechanical ventilation mode on intra-and postoperative blood loss in patients undergoing posterior lumbar interbody fusion (PLIF) surgery. Methods According to the random number table method, a total of 88 patients scheduled to undergo lumbar spine surgery were randomly divided into two groups. Patients were received pressure controlled ventilation and volume controlled ventilation in pressure controlled ventilation (PCV group, n=44) and volume controlled ventilation (VCV group, n=44). Mean arterial pressure (MAP), heart rate (HR) and central venous pressure (CVP) were monitored at the onset of anesthesia induction (T0), 10 min after supine position to prone position (T1) and skin closure immediately (T2), 10 min after prone position to supine position (T3) and when tracheal extubation (T4) respectively, and were determined at the above time points of two groups of hemoglobin (Hb) and hematocrit (Hct). The respiration parameters were recorded from T0 to T3. The indicators were recorded in the two groups as following: the volume of intranperative blood loss, 72 h postoperative blood loss, the volume of allogeneic blood transfusion, the volume of fluid input and the rate of re-operation for stopping the bleeding. Results Compared with VCV group, peak inspiratory pressure (PIP) were all lower increasingly from T1 to T3 in PCV group (P 0.05). The differences of Hb and Hct at different time points between the two groups have no statistical significance (P>0.05). Compared with VCV group, the volume of intranperative blood loss, the amount of transfused plasma and red blood cells were all notably lower in PCV group (P>0.05). Conclusion Intraoperative PCV can decrease intraoperative blood loss in patients undergoing PLIF, which may be related to lower intraoperative peak inspiratory pressure. Key words: Pressure controlled ventilation; Volume controlled ventilation; Lumbar spine surgery