俯卧位、可调节斜位气道压增高对腰椎术中出血量的预测

Effect of Increased Airway Pressure on Intraoperative Blood Loss in Patients with Prone or Adjustable Oblique Position in Lumbar Surgeries

目的观察俯卧位(A组)、可调节斜位(B组)时气道压变化对腰椎手术出血量的预测作用。方法选择择期腰椎后路手术患者72例,ASAⅠ或Ⅱ级,全麻气管插管机械通气后,记录仰卧位10min(T0)、摆放俯卧或斜位后15min(T1)及60min(T2)时气道峰压(PPeak)、气道平台压(PPlat),平均动脉压(MAP)及动脉血气分析结果,术毕统计出血量、计算肺顺应性等。结果①摆放体位后PPeak、PPlat均升高、肺顺应性均降低,组内T1、T2与T0时比较差异均有统计学意义(均P<0.05),且A组变化明显大于B组;②翻身前后患者动脉血气分析结果差异无统计学意义(P>0.05);③A组术中出血量明显大于B组。且A组术中出血量随PPeak、PPlat增高而显著性增加(R2=0.65、0.55,P<0.05);而B组无此现象(R2=0.04、0.05,P>0.05)。结论俯卧位、可调节斜位均影响全麻患者通气功能,且俯卧位对肺通气影响大于可调节斜位,但二者对肺换气功能无明显影响;俯卧位PPeak、PPlat的增高可预测术中出血量,而可调节斜位气道压的变化不能预测术中出血量。

Objective To evaluate the effect of increased airway pressure resulting from the prone or adjustable oblique po sition of patients on intraoperative blood loss during lumbar spine surgery. Methods Seventy-two patients who underwent pos- terior spinal surgery and were classified as American Society Anesthesiologist classification I or U （ASA）were enrolled in the study. The peak airway pressure（Ppeak）, plateau airway pressure（Pplat）, mean artery pressure（MAP）and arterial blood gas test （ABG）result were recorded 10 min after general anesthesia induction in supine position（T0 ）and 15 min（T1 ）, 60 min（T2 ）after turning the patients into prone or adjustable oblique position. Intraoperative blood loss was measured and the total iung or tho- rax compliance was calculated at the end of surgery. Results Ppeak and PPlat were significantly increased after placement of pa- tients from the supine position to the prone or adjustable oblique position（P〈0.05）. There was no significant difference in the ABG results between the prone/oblique position group and the supine position group. In the prone group, the intraoperative blood loss was significantly higher than in the oblique group,and was significantly correlated with Ppeak and Pplat changes（R^2= 0.65,0.55,P〈0.05）;however,in the oblique group, there was no significant correlation between the blood loss and Ppeak/Pplat changes（R^2= 0. 04,0. 05,P〉0. 05）. Conclusion Prone and adjustable oblique positioning can influence pulmonary ventilation function without affecting the air exchange function of patients under general anesthesia. Increase in the airway pressure can af- fect the intraoperative surgical blood loss in patients assuming prone position rather than the adjustable oblique position.