肝移植病人围术期低氧血症的防治

目的：探讨肝移植病人围术期影响呼吸功能的因素以及对低氧血症的预防和治疗措施。方法：回顾性分析了3例背驮式原位肝移植（POLT）患者的临床资料,对肝移植病人围术期发生的呼吸功能不全的原因进行分析,结果：围术期存活2例,死亡1例,术后并发急性呼吸衰竭,感染,急性排斥反应,肾衰等。结论：减少外科手术并发症是提高肝移植患者手术成功率以及长期存活的关键;呼吸“泵”衰竭是低氧血症形成的重要原因之一;及时有效的氧疗和机械通气是治疗肝移植病人术后并发症的一项重要措施。     

手术方法对施择期腭成形术小儿手术后早期低氧血症的影响

目的评价不同手术方法对施择期腭成形术小儿手术后早期低氧血症的影响。方法选择321例美国麻醉医师协会(ASA)I级、年龄8个月～14岁拟行腭成形术的患儿,根据不同手术方法将其分为3组。所有患儿采用静吸复合全身麻醉。手术后到达恢复窒即刻(0min)和5、10、15、20、30、40、50、60、120和180min时,记录患儿呼吸空气时的Sp(O2)。结果患儿接受的腭成形术越复杂,其在手术后早期的Sp(O2)水平越低、Sp(O2)的恢复越慢和低氧血症发生率越高。手术后早期的Sp(O2)水平和低氧血症发生率在3组间具有显著差异。结论腭成形术患儿手术后早期Sp(O2)降低严重程度和低氧血症发生率与手术方法密切相关。患儿到达恢复室时的Sp(O2)水平和低氧血症发生率与麻醉恢复评分密切相关,说明术后呼吸功能的恢复取决于麻醉恢复程度。     

Modelling of hypoxaemia after gynaecological laparotomy

BACKGROUND: Late postoperative arterial hypoxaemia is common after major surgery, and may contribute to cardiovascular, cerebral or wound complications. This study investigates the time course of hypoxaemia following gynaecological laparotomy, and estimates parameters of mathematical models of pulmonary gas exchange to describe hypoxaemia. METHODS: Twelve patients were studied on four occasions; preoperatively, 2, 8 and 48 h after surgery. On each occasion inspired oxygen fraction (FIO2) was varied, changing end-expired oxygen fraction (FEO2) to achieve arterial oxygen saturations (SaO2) ranging from 90% to 100%. Measurements of ventilation and blood gases were taken. Oxygenation was characterized plotting FEO2 against SaO2. The shape and position of the FEO2/SaO2 curve was described using two mathematical models including parameters describing gas exchange: either shunt and resistance to oxygen diffusion (Rdiff); or shunt and asymmetry of ventilation-perfusion (fA2). RESULTS: Two hours after surgery SaO2 was reduced from 97.5%+/-1.2% (mean+/-SD) to 93.8%+/-2.7% (mean+/-SD) (P<0.001). Values of shunt, Rdiff and fA2 were significantly changed at 2 and 8 h postoperatively. Forty-eight hours postoperatively Rdiff and fA2 were still significantly changed. CONCLUSION: Oxygenation in 12 patients preoperatively, 2, 8 and 48 h after gynaecological laparotomy is described. Two patients were hypoxaemic (SaO2 <92%) 48 h postoperatively. When two different models of oxygen transport are fitted to patient data, high values of Rdiff or low values of fA2 describe the right shift in the FEO2/SaO2 curve seen in patients with oxygenation problems. These models fit patient data identically, and may be useful in quantifying postoperative hypoxaemia.     

Bain呼吸环路防治单肺通气犬肺内分流量增加的实验研究

对15条单肺通气(OLV)犬模型进行实验,观察手术侧肺加用或不用Bain环路对犬肺分流量和氧合的影响。结果提示:与双肺通气(TLV)相比,不用Bain的OLV犬,动、静脉氧分压(PAO_2、P(?)O_2),动、静脉血氧饱和度(SaO_2、S(?)O_2)分别降低了49％、11％、8％、14％;肺泡气与动脉血氧分压差(_(A-a)DO_2),肺毛细血管-动脉血氧含量差(C_cO_2-CaO_2),肺毛细血管-静脉血氧含量差(C_cO_2-C(?)O_2)和肺分流量(Q_(?)/Q_t),分别增加了39％、350％、50％和190％(均为P<0.01)。提示低氧血症与OLV时严重肺内分流、静脉血掺杂有关。而使用Bain的OLV犬氧合良好,PaO_2、P(?)O_2稍有增高,~(A-a)DO_2和Q_(?)/Q-t分别降低了19.3％和8％(均为P>0.05)。Bain环路能将氧气以一定的压力和流速持续吹入肺泡,使其扩张并行气体交换,达到改善术侧肺功能和防治肺内分流量增加的目的。     

Pulse oximetry,capnography, and blood gas measurements: reducing cost and improving the quality of care with technology

Pulse oximetry appears to improve quality of care by the early detection of hypoxia noninvasively. We tested the hypothesis that the widespread use of pulse oximetry over a 5-year period in the operating rooms at our institution had resulted in a reduction in blood gas measurements and in departmental operating costs. The total number of blood gas determinations per hour of anesthetic time at our institution decreased by 44%, from 7.64 to 4.26 measurements per 100 operating room hours. The number of capnography units in the operating rooms increased from 8 to 14, the number of pulse oximeters increased from 0 to 22, and oximeter use increased from 0 to 100% for all anesthetics. The total cost to provide oximetry, capnography, and blood gas measurements in 1989–1990 was less than the cost to provide blood gas measurements alone in 1985–1986. The introduction of these technologies was accomplished without an increase in cost: $76,880 in 1985–1986 versus $71,025 in 1989–1990.     

Distribution and morphometry of skeletal muscle fibers in patients with chronic obstructive pulmonary disease and chronic hypoxemia

This study was designed to assess the size and distribution of muscle fiber types in patients with severe chronic obstructive pulmonary disease and stable chronic hypoxemia. Brachial biceps biopsies were performed in 8 patients and 12 controls. Histochemistry was used to count and determine the cross-sectional area of the various fiber-types (1, 2a, and 2b). A significant reduction (P < 0.05) in the proportion of type 2a fibers and an increase in the proportion and cross-sectional area of type 2b fibers were seen in hypoxemic patients. These findings suggest an adaptation of the muscle fibers to a low partial pressure of oxygen in arterial blood.     

急性冠脉综合征患者夜间低氧血症对颈动脉硬化斑块的影响

目的研究急性冠脉综合征（ACS）患者夜间低氧血症对颈动脉粥样硬化斑块的影响。方法将110例ACS患者根据冠脉造影检查和睡眠呼吸监测结果分为三组：ACS组（Ⅰ组,n=37）、ACS合并阻塞型睡眠呼吸暂停低通气综合征-轻度以下夜间低氧血症组（Ⅱ组,n=36）、ACS合并阻塞型睡眠呼吸暂停低通气综合征-中度以上夜间低氧血症亚组（Ⅲ组,n=37）。所有患者均行颈动脉超声检查,对各组间颈动脉内膜中层厚度、斑块数量进行分析,并以Gensini积分比较不同组间冠脉病变严重程度。结果三组在传统冠心病危险因素差异无统计学意义（P〉0.05）,与Ⅰ组比较,Ⅱ组和Ⅲ组患者颈动脉内膜明显增厚,颈动脉斑块数明显增多（P〈0.01）;Ⅲ组比Ⅱ组颈动脉内膜明显增厚,总斑块数、软斑块数显著增多（P〈0.01）,混合斑块数、硬斑块数也明显增多（P〈0.05）;Ⅱ组和Ⅲ组中颈动脉IMT及斑块数量与夜间最低血氧饱和度成负相关;Ⅱ组与Ⅰ组Gensini积分无统计学差异（P〉0.05）。Ⅲ组Gensini积分明显高于Ⅰ组和Ⅱ组（P〈0.01）。结论夜间低氧血症对ACS患者颈动脉粥样硬化及斑块的形成可能具有一定作用。