CO2部分重吸入法测心排血量在冠脉搭桥术中的应用

目的 观察CO2部分重吸入法测心排血量在冠脉搭桥术中的应用。方法 选择冠脉搭桥术26例,于诱导后、切皮、体外循环转流前、停转流后60min、停转流90min、术毕及术后监护室各时点采用CO2部分重吸入法测心排血量（RBco),并与温度稀释法（TDco)作比较。结果 于诱导后、切皮、停转流90min、术毕、术后监护室RBco和TDco测量数值均无显著性差异（P＞0．05）,于转流前、转流后60min测量值有显著性差异（P＜0．05）。各时点RBco和TDco相关系数均P＜0．01,其中术后监护室中的相关系数最高,r＝0．8511。结论 CO2部分重吸入法测心排血量在冠脉搭桥术术后监测中有良好的准确度,术中监测也有一定的临床价值。     

家兔CO2气腹时胰岛素抵抗的发生

目的 评价家兔CO2气腹时胰岛素抵抗的发生.方法 雄性家兔10只,随机分为2组(n=5),对照组和实验组CO2气腹压力分别为0、15 mm Hg,时间1 h.于气腹前、气腹30、60 min、气腹后4、24 h测定血浆葡萄糖、胰岛素、肿瘤坏死因子-α(TNF-α)水平及红细胞的胰岛素高亲和力受体、低亲和力受体的亲和常数和结合位点数,计算胰岛素敏感指数.结果 与对照组比较,实验组气腹中及气腹后血浆葡萄糖、胰岛素和TNF-α水平均升高,气腹后胰岛素敏感指数降低(P＜0.05或0.01),气腹中及气腹后红细胞的胰岛素高亲和力受体、低亲和力受体的亲和常数和结合位点数差异无统计学意义(P＞0.05).结论 15 mm Hg CO2气腹1 h可引起家兔血浆葡萄糖和胰岛素水平升高,胰岛素敏感性降低,发生了胰岛素抵抗.     

高浓度二氧化碳预处理对人脐静脉内皮细胞缺氧复氧损伤的影响

目的 探讨高浓度二氧化碳(CO2)预处理对人脐静脉内皮细胞缺氧复氧损伤的影响.方法 人脐静脉内皮细胞接种于细胞培养板,随机分为6组,每组16孔,对照组(C组)常规培养;缺氧复氧组(MR组)缺氧4 h、复氧24 h;缺氧预处理组(APC组)缺氧10 min、复氧10 min,重复2次后缺氧4 h、复氧24 h;HCA.组、HCA2组和HCA3组分别于50%N-20%02-30%CO2培养箱中行30%CO2预处理10、30、60 min后常规培养10、20、30 min,缺氧4 h、复氧24 h.于复氧24 h时采用MTY法测定人脐静脉内皮细胞活力,采用免疫细胞化学法测定细胞间粘附分子-1(ICAM-1)表达水平.结果 与C组比较,MR组、APC组、HCA1～3组人脐静脉内皮细胞活力降低,ICAM-1表达上调(P＜0.05);与A/R组比较,APC组和HCA2组人脐静脉内皮细胞活力升高,APC组及HCA1,2组ICAM-1表达下调(P＜0.05).结论 高浓度CO2预处理可减轻人脐静脉内皮细胞缺氧复氧损伤.     

Heating of carbon dioxide during insufflation alters the peritoneal fibrinolytic response to laparoscopic surgery

Background Laparoscopic surgery is evolving rapidly. It involves the creation of a pneumoperitoneum, mostly using carbon dioxide. Cooling of the peritoneum, due to insufflation, might traumatize the peritoneum and disturb peritoneal fibrinolysis, important in peritoneal healing processes. The current study was performed to elucidate the effects of the temperature of insufflation gas on the peritoneal fibrinolytic response to laparoscopic surgery. Methods Thirty patients scheduled for laparoscopic cholecystectomy were randomized in two groups: one group in which the pneumoperitoneum was created with carbon dioxide at room temperature, and one wherein carbon dioxide at body temperature was used. Peritoneal biopsies were taken at the start and at the end of surgery. Tissue concentrations of tPA antigen, tPA activity, uPA antigen, and PAI-1 antigen were measured using ELISA techniques. Results Peritoneal PAI-1 antigen levels were significantly higher at the end of the procedure in patients operated with carbon dioxide at room temperature (p < .05). A slight, but not significant, decrease in tPA antigen and activity was observed in both groups during the procedure. Peritoneal concentrations of uPa antigen did not change during the procedure. Conclusions The temperature of carbon dioxide used for insufflation of the abdominal cavity affects peritoneal biology. Cooling of the peritoneum by unheated carbon dioxide causes increased peritoneal PAI-1 levels, important in peritoneal healing processes.     

Soda lime temperatures during low-flow sevoflurane anaesthesia and differences in dead-space

BACKGROUND: Sevoflurane degrades during low-flow anaesthesia to compound A, and high carbon dioxide absorbent temperatures cause increased degradation. The purpose of this investigation was to determine if larger tidal volumes, without increasing alveolar ventilation, decrease the temperature in the carbon dioxide absorber during low- and minimal-flow sevoflurane anaesthesia. METHODS: Prospective, randomized study, including 45 patients (ASA 1-2), scheduled for elective general or urology surgery. The patients were randomly assigned to one of three treatments. Patients in group 1 (NDS) received fresh gas flow of 1 litre/min without using additional dead-space volumes. In group 2 (DS + 1.0), the patients received fresh gas flow of 1 litre/min using additional dead-space volumes, placed between the Y-piece and the HME, and patients in group 3 (DS + 0.5) received the same technique with a fresh gas flow of 0.5 litre/min. The soda lime temperatures, dead-space volumes, end-tidal carbon dioxide, sevoflurane concentrations, ventilation volumes and pressures, absorbent weight and ear temperatures were measured. RESULTS: The maximum temperature of the soda lime was 44.1 +/- 1.1 degrees C in the NDS group, 37.8 +/- 0.8 degrees C in the DS + 1.0 group and 38.5 +/- 2.7 degrees C in the DS + 0.5 group (P<0.0001). The dead-space volume between the Y-piece the tracheal tube was 164 +/- 69 ml in the DS + 1.0 group and 196 +/- 15 ml in the DS + 0.5 group (P<0.05). The ventilator pressure were higher in the DS groups compared with the NDS group (P<0.001). Soda lime weight increased in all groups. End-tidal carbon dioxide, sevoflurane concentrations and ear temperatures were similar between the groups. CONCLUSION: Increasing dead-space volumes can reduce carbon dioxide absorber temperature during low- and minimal-flow sevoflurane anaesthesia.     

Dynamic skin cooling with an environmentally compatible alternative cryogen during laser surgery

BACKGROUND AND OBJECTIVES: Cryogen spray cooling with tetrafluoroethane (R134a) has been used to enhance epidermal protection during dermatologic laser surgery. However, R134a has a very high global warming potential (GWP = 1300). Our objective was to evaluate the cooling effectiveness of an alternative cryogen with a much lower GWP, namely liquid carbon dioxide (CO(2), GWP = 1). STUDY DESIGN/MATERIALS AND METHODS: A thin-film thermocouple deposited on an epoxy skin phantom was used to measure surface temperature (T(s)) variations induced by R134a or CO(2) sprays. The temperature distribution in the skin phantom was estimated using T(s) and Duhamel's method. Impact pressure and noise level of both cryogen sprays were measured with a dynamic sensor and sound meter, respectively. Consumption of both cryogens was also evaluated. RESULTS: For R134a sprays, T(s) was kept almost constant after 15 milliseconds. For CO(2) sprays, T(s) decreased continuously during the entire spurt of 50 milliseconds. The minimum T(s) induced by the CO(2) sprays was lower than that induced by R134a when the spurt duration was longer than 35 milliseconds. Numerical simulation shows that CO(2) sprays were able to induce very similar temperature reductions in the skin phantom as compared to R134a sprays when the spurt duration and delay time were selected appropriately. R134a sprays induced an impact pressure of 3.6 kPa, as compared to 43.1 kPa for CO(2) sprays. The maximum noise level for R134a sprays was 109 dBA as compared to 135 dBA for the CO(2) sprays. The R134a consumption for a 50 milliseconds spurt is 67 mg as compared to 225 mg for a CO(2) spurt of the same duration. CONCLUSIONS: CO(2) sprays are expected to have similar skin cooling efficacy as R134a sprays. Although the CO(2) consumption is higher than R134a, its contribution to global warming is still much less than R134a. The effects of varying spurt durations on in vivo human skin and the impact on cutaneous blood flow require further investigation.     

翻转大翼软骨瓣辅助硅胶假体置入隆鼻术

目的 探讨一种在应用硅胶假体进行隆鼻术时防止假体外露,同时有利于鼻尖与鼻翼成形,并有效增加鼻长的手术方法.方法 在16例临床隆鼻手术中,应用翻转大翼软骨瓣辅助硅胶鼻假体置入的方法,术中离断大翼软骨外侧脚,保留内侧脚完整,单端游离大翼软骨至鼻尖,充分松解大翼软骨对鼻尖的牵拉,以便在增高鼻背的同时增加鼻长,并满足个性化鼻尖与鼻翼成形.结果 16例受术者全部Ⅰ期愈合,无感染及假体外露等并发症发生.术后1个月回访,鼻尖高度及鼻长明显增加,鼻形自然,鼻翼立体感不仅未受影响,反而不同程度地得到优化,鼻尖与鼻翼轮廓清晰.结论 应用翻转大翼软骨瓣辅助硅胶鼻假体置入的隆鼻方法,可有效防止要求较高隆起鼻梁、鼻尖时造成的假体外露风险,同时有助于实现个性化鼻尖与鼻翼成形.由于软骨瓣取材方便、无需第2术区,软骨瓣血运有保障,不易发生变形和吸收,是提高隆鼻术美容效果的可行方法.     

低流量七氟烷吸入麻醉时不同二氧化碳吸收剂环路中化合物A浓度的比较及其对患者肝肾功能的影响

Objective To investigate the influence of different carbon dioxide (CO2) absorbents (Dr(a)gersorb 800 plus , Sodasorb,Sodasorb LF) on the production of compound A during low-flow sevoflurane anesthesia.Methods Twenty-seven ASA Ⅰ or Ⅱ patients aged 20-64 years were randomly assigned to three groups according to different CO2 absorbents: Dr(a)gersorb 800 plus' group (group D, n = 10), Sodasorb group (group S, n = 10) and Sodasorb LF group (group LF, n = 7). Anesthesia was maintained with low-flow (500 ml/min) sevoflurane inhalation (with the end-tidal sevoflurane concentration of approximately 2% ). At 2 h after low-flow sevoflurane anesthesia, gas samples were taken from the expiratory limb of the circuit. Compound A was detected by gas chromatography. Serum alanine transaminase (ALT), aspartate aminotransferase (AST), bilirubin (BR), urea nitrogen (BUN) and creatinine (Cr) levels were measured before (T0 ) and 24 h after operation (T1).Results The three groups were comparable with respect to age, body weight and height. After 2 h of low-flow sevoflurane anesthesia, compound A concentrations in the expiratory limb of the circuit were 11.6 ± 5.8 (group D), 2.1 ± 1.9 (group S)and ＜ 0.1 ppm (group LF), respectively. There were no significant changes in the serum ALT, AST, BR, BUN and Cr levels at 24 h after operation as compared with the preoperative baseline values in the three groups.Conclusion After 2 h of low-flow (500 ml/min) sevoflurane anesthesia, compound A concentrations within the circuit with different CO2 absorbents ( Dr(a)gersorb 800 plus' , Sodasorb, Sodasorb LF) are less than 50 ppm, with the lowest in Sodasorb LF.However, they have no significant effects on hepatic or renal function.     

自体真皮瓣在隆鼻手术中的应用

目的 探讨自体真皮瓣游离移植结合多种材料在隆鼻手术中的应用。方法 2014年1月至2015年1月,根据患者鼻部的情况,对31例隆鼻患者采取自体真皮瓣结合硅胶假体、耳甲腔软骨综合隆鼻,并观察临床效果。结果本组患者术后真皮成活良好,鼻部外形自然、满意。随访6~12个月,除1例术后并发感染,经积极抗炎治疗有效,其余患者无并发症产生。结论 自体真皮瓣结合硅胶假体、耳甲腔软骨等综合隆鼻,可降低假体外露等并发症的发生率,术后鼻部外形自然,效果良好。     

Simultaneous Automatic Control of Oxygen and Carbon Dioxide Blood Gases During Cardiopulmonary Bypass

In this work an automatic control strategy is presented for the simultaneous control of oxygen and carbon dioxide blood gas partial pressures to be used during cardiopulmonary bypass surgery with heart–lung machine support. As the exchange of blood gases in the artificial extracorporeal lung is a highly nonlinear process comprising varying time delays, uncertainties, and time‐varying parameters, it is currently being controlled manually by specially trained perfusionist staff. The new control strategy includes a feedback linearization routine with augmented time‐delay compensation and two external linear gain‐scheduled controllers, for partial oxygen and carbon dioxide pressures. The controllers were robustly tuned and tested in simulations with a detailed artificial lung (oxygenator) model in cardiopulmonary bypass conditions. Furthermore, the controllers were implemented in an ex vivo experiment using fresh porcine blood as a substitute fluid and a special deoxygenation technique to simulate a patient undergoing cardiopulmonary bypass. Both controllers showed robust stability during the experiments and a good disturbance rejection to extracorporeal blood flow changes. This automatic control strategy is proposed to improve patient's safety by fast control reference tracking and good disturbance rejection under varying conditions.