老年重症开胸手术围术期呼吸循环变化与呼吸并发症的相关性

目的 探讨老年病人术后呼吸并发症的发生原因及预防策略.方法 对58例高龄或重要脏器有合并症,及行大手术的老年重症开胸手术病人（组1）进行围术期呼吸、循环监测,记录脱氧动脉血气、出入液量、尿比重、漂浮导管血流动力学指标,并与56例非老年病人（组2）进行比较.结果 全组12例呼吸并发症均见于老年重症病人（组1A）,10例为术后早期低氧血症,均始发于术后第2、3 d,另2例为后期感染引起Ⅱ型呼吸衰竭（呼衰）.多因素回归分析示术前呼吸道合并症和肥胖是老年病人术后发生呼吸并发症的独立预测因素.组1A术后前3 d PaO2显著低于未发生呼吸异常的老年病人（组1B）及组2,组1A与组1B术后PaCO2变化相似均显著低于组2.三组间术后第1 d液体出入平衡差异显著,组2为负平衡（-243ml）,组1B为轻度正平衡（＋109ml）,而组1A则为显著的正平衡（＋832ml）,术后前3 d尿比重均显著高于组2.漂浮导管监测发现老年病人术后前3 d心排量上升、外周血管阻力降低表现为循环高动力状态,而肺血管阻力则明显高于术前.结论 老年病人术前呼吸道合并症多见,其是术后易发生呼吸并发症的主要危险因素,呼吸异常是老年重症病人开胸手术后最主要的并发症和死亡原因,手术创伤引起的细胞外液增加所致＂相对性肺水肿＂是造成术后早期容易出现呼吸失代偿的内在因素.减轻创伤应激和严格输液管理可能有助于预防呼吸并发症的发生,密切监护老年病人的呼吸循环指标、尤其是脱氧动脉血气分析以及尿量、尿比重变化趋势,有助于及早发现呼吸异常并及时介入处理以避免发展成为呼吸衰竭.

The relationship between respiratory-circulatory changes and pulmonary complications in elderly patients after thoracotomy

Objective To study the respiratory and circulatory changes in elderly patients, and their relationship with pulmonary complications after thoracotomy. Methods 58 elderly patients either aged over 75 years, with major organ dysfunction or underwent highly invasive procedures (group 1). Respiratory and circulatory status, including arterial blood gas under room air, water balance, urine gravity, and hemodynamics monitoring through pulmonary artery catheter were documented. The results were compared with those from 56 young patient controls receiving thoracotomy in the same period (group 2). Results All 12 patients having pulmonary complications were from group 1 (group 1A). Ten of them presented on the 2nd or 3rd postoperative day with hypoxemia. The other 2 died of type II respiratory failure after severe infection. Preoperative pulmonary co-morbidity (P=0.026, Exp(B)=5.4) and obesity (P=0.043, Exp(B)=4.9) were identified as independent risk factors for pulmonary complications after thoracotomy in elderly patients. During the first 3 postoperative days, PaO_2 of group 1A was significantly lower than group 2 as well as the other elderly patients who did not develop pulmonary complications after surgery (Group 1B). PaCO_2 of group 1A and 1B were significantly lower than group 2. There were also significant differences between the three groups in water balance on the first postoperative day (group 1A +832ml, P=0.006 vs. group 1B +109ml, P=0.004 vs. group 2 -243ml ). Urine gravity in group 1A was also significantly higher than in group 2 in the first 3 postoperative days. Pulmonary artery catheter monitoring revealed increased cardiac output and decreased systemic vascular resistance, showing a hyperdynamic status, in elderly patients after surgery. Pulmonary vascular resistance was elevated in the same time. Conclusion Pulmonary co-morbidities commonly seen in elderly patients are responsible for pulmonary complications, the major cause of surgical mortality after thoracotomy. Hypoxemia in the early postoperative period is mainlycaused by relative volume overloading from trauma induced interstitial edema. Close monitoring of arterial blood gas under room air, water balance, and urine gravity after thoracotomy may identify elderly patients at risk of developing pulmonary complication and prompt timely intervention.