The Venturi Anaesthesia Circuit III Carbon Dioxide Elimination

The Venturi circuit was studied with regard to CO2 elimination in a model experiment. A mean concentration of 0.6% CO2 in the fresh gas supply to the patient was accepted. The experiments demonstrated that a soda-lime charge of 200 g will cover the elimination requirements of CO2 in a Venturi circuit for any patient below 100 kg b.w. for a period of 3 h, while a soda-lime charge of 300 g will suffice for 5 h. The utilization of the soda lime charge is of the same order of magnitude as that of the much larger canisters used in circle circuits. In the Venturi circuit, the size of the soda-lime charge can be adjusted to suit the body weight of the patient and the expected length of the anaesthetic procedure. One soda-lime charge for each anaesthetic procedure is preferable from the point of view of hygiene. The charge should not be less than 200 g.     

Energy Expenditure on Breathing during Anaesthesia

Measurements of carbon dioxide production were carried out on 20 patients undergoing arthroplastic operation of the hip joint, under halothane anaesthesia supplemented with lumbar plexus block. Compared to spontaneous respiration, the carbon dioxide production during controlled ventilation, with and without muscular relaxation, showed a decrease of 19% and 12%, respectively.     

The Effect of Epidural and General Anaesthesia on Lymphocyte Functions during and after Major Orthopaedic Surgery

The blastogenic responses of lymphocytes to PHA-stimulation and lymphocyte lymphokine production have been studied in 27 patients undergoing total hip replacement, operated under either general anaesthesia or epidural anaesthesia. The lymphocytes were isolated from the patients the day before operation, during the operation and on the first postoperative day. The assays were carried out with lymphocytes cultured in medium containing 25% of the patient's serum (Au-medium) and in medium containing 25% of pooled AB+ serum (AB-medium). In the epidural anaesthesia group, the blastogenic response to PHA of lymphocytes incubated in Au-medium increased per- and postoperatively to 132% (n.s.) and 155% (P less than 0.05) compared to preoperative values. In the general anaesthesia group, the PHA-response decreased to 63.7% peroperatively (P less than 0.05) and 88.7% postoperatively (n.s.). When the lymphocytes were incubated in AB-medium, the PHA-response increased in both groups. Lymphocyte lymphokine production in the epidural group was unchanged both per- and postoperatively in both media. However, in the general anaesthesia group there was a reduction in lymphokine activity both per- and postoperatively. This reduction was most pronounced peroperatively when the lymphocytes were incubated in Au-medium (64.2%, P less than 0.05). Control lymphocytes incubated in sera from general anaesthetized patients resulted in significantly lower lymphokine activity (P less than 0.05) in comparison with cultures with sera from patients in the epidural group. These findings indicate a lymphocyte depressing factor in serum from patients operated under general anaesthesia, which is absent during operations in epidural anaesthesia.     

悬吊式无气腹与气腹腹腔镜手术对妇科病人应激反应的影响

目的比较妇科无气腹悬吊式腹腔镜和气腹腹腔镜手术对病人应激反应影响的差异。方法采用前瞻性对照研究的方法,选择2005年7月～2006年2月择期行腹腔镜下卵巢肿瘤切除术38例,按患者意愿分成2组,每组19例。Ⅰ组于全麻下行CO2气腹腹腔镜手术;Ⅱ组于全麻下行悬吊式腹腔镜手术。监测2组患者麻醉前（T1）、气腹或悬吊建立后30min（T2）、气腹或悬吊撤除后10 min（T3）和术后次日晨8时（T4）4个时点的血糖、胰岛素、皮质醇、TNF-α和IL-6水平。结果麻醉前2组血糖、胰岛素、皮质醇、TNF-α和IL-6水平差异无显著性（P〉0.05）。气腹或悬吊后上述各指标水平均升高（P〈0.05）。其中胰岛素水平逐渐升高,至T4时最高。Ⅰ组的血糖、皮质醇、TNF-α和IL-6水平至T3时最高,Ⅱ组至T4时最高。组间比较,在T2时点,Ⅰ组的皮质醇和TNF-α水平高于Ⅱ组（P〈0.05）,在T3时点,Ⅰ组的血糖、皮质醇、TNF-α和IL-6水平均显著高于Ⅱ组（P〈0.01）。结论无气腹悬吊式腹腔镜技术免除了CO2气腹对机体的影响,降低了术中应激反应水平。     

Differential Ventilation and Selective PEEP During Anaesthesia in the Lateral Decubitus Posture

The potential of differential ventilation (DV) with selective positive end-expiratory pressure (PEEP) has been tested versus conventional ventilation with and without general PEEP. Gas exchange and central haemodynamics were studied in 15 subjects with no clinical or radiological signs of pulmonary disease. The rationale of the method was to ensure ventilation of the well-perfused dependent lung and to counteract airway closure within that lung. The subjects were intubated with a double-lumen catheter prior to scheduled abdominal surgery. During general anaesthesia in the lateral posture, they were given DV. The mean inspired oxygen fraction was 0.32. Fifty per cent ("even" tidal volume (VT) distribution) or 70% ("inverted" VT distribution) of the inspired volume was administered to the dependent lung. Two synchronized ventilators were used. In eight subjects DV was also combined with PEEP applied solely to the dependent lung (selective PEEP). The major findings were that DV with even VT distribution reduced venous admixture by 26% ( P <0.05) and the alveolo-arterial oxygen tension gradient (P(A-a)o2) by 30% ( P <0.05) in comparison with conventional ventilation in the lateral position. The addition of selective PEEP further reduced the P(A-a)o2 by 13%. P(A-a)o2 was consequently 43% lower than during conventional ventilation without PEEP in the lateral posture ( P <0.01). Selective PEEP also had less impact on cardiac output than general PEEP (P<0.05). It is concluded that DV with even distribution of VT and selective PEEP can reduce the P(A-a)o2 in anaesthetized lung-healthy subjects in the lateral position.     

Carbon Dioxide Laser Resurfacing of Rhytides and Photodamaged Skin

Carbon dioxide (CO₂) laser resurfacing has been used as a method to treat rhytides and photodamaged skin. This laser offers several advantages over previously utilised modalities but its use has several inherent risks. This article will review important aspects of CO₂ laser resurfacing including laser-skin interactions, patient selection, effective pre- and post-operative regimens and potential complications. Received for publication 3 January 1998; accepted 24 February 1998     

The effect of insufflation pressure on pulmonary mechanics in infants during laparoscopic surgical procedures

BACKGROUND: Few studies have reported objective measurements of pulmonary changes under controlled conditions in infants undergoing laparoscopic procedures. We objectively measured the pulmonary effects of laparoscopically-induced pneumoperitoneum in infants less than 1 year of age undergoing surgical procedures under general anaesthesia. METHODS: Nineteen ASA I-II patients less than 1 year of age were enrolled in this direct observational study. Anaesthetic technique included inhalation induction using sevoflurane/O2/air and neuromuscular blockade. Infants were ventilated using 10-15 ml.kg-1 tidal volume at a respiratory rate sufficient to achieve normocarbia [PECO2 4.6-5.8 kPa (35-45 mmHg)]. Opioids and regional anaesthesia techniques were used when appropriate. Peak inspiratory pressure (PIP), expiratory tidal volume (Vt), endtidal carbon dioxide concentration (PECO2) and dynamic compliance (COMPdyn) were recorded at baseline, 5, 10 mmHg and maximal insufflation pressure (Pmax). Pmax was limited to 12 mmHg for infants <5 kg, 15 mmHg for infants >5 kg. At steady state Pmax, ventilator changes were implemented to restore Vt and PECO2 to within 10% of baseline. Each patient served as his own control. RESULTS: At Pmax, average PIP increased 18%, average Vt decreased 33%, average PECO2 concentration increased 13%, average COMPdyn decreased 48%; O2 saturation fell in 41% of patients. Twenty ventilator adjustments were required; one patient experienced no changes in measured pulmonary mechanics, requiring no ventilator changes. CONCLUSIONS: Pulmonary mechanics in infants change significantly during laparoscopic CO2 pneumoperitoneum; the magnitude of change correlates directly with intraperitoneal pressure. Greater than 90% of infants required at least one ventilatory intervention to restore baseline Vt and PECO2.     

The Effect of Sodium Citrate on the pH and the Amount of Gastric Contents Before General Anaesthesia

Sixty patients were prospectively studied with respect to the volume and pH of their gastric contents after allocation to one of three preoperative treatments. All patients received diazepam (Apozepam) 5 mg the night before operation and 10 mg at 06.30 on the morning of operation. One group received sodium citrate solution 50 ml perorally at 06.30, 75-370 min before operation. A second group received water 50 ml perorally at 06.30, 100-405 min before operation. The third group received 50 ml water at 06.30 and 50 ml sodium citrate solution perorally just before admission to the operation theatre, 15-50 min before aspiration. Statistical analysis showed elevated pH and volume of gastric contents in the group receiving water in the morning and sodium citrate solution just before admission to the operating theatre immediately after induction of anaesthesia. There was no statistically significant difference of pH and aspirated volume between the group receiving water and the group receiving sodium citrate at 06.30.     

全麻腹腔镜胆囊切除术呼吸频率及潮气量的调控

目的 探讨全麻腹腔镜胆囊切除术(LC)气腹后呼吸频率及潮气量的调控。方法ASAⅠ～Ⅱ成人患48例，随机分成4组，全麻气管插管后机器控制呼吸，呼吸频率10次／min，潮气量10mL／kg，气腹后Ⅰ组维持不变，Ⅱ、Ⅲ、Ⅳ组潮气量改为8mL／kg，呼吸频率分别为14次／min、16次／min、18次／min，监测患气腹前及气腹后20min的平均动脉压(MAP)、呼气末二氧化碳分压(PETCO2)、气道压力峰值(PEAK)。结果Ⅰ组气腹后PETCO2显升高，显示有通气不足，同时MAP、PEAK均显升高。Ⅳ组PETCO2下降，显示有过度通气。Ⅱ、Ⅲ组PETCO2正常。结论全麻腹腔镜胆囊切除术气腹后采用8ml／kg的潮气量和14～16次／min的呼吸频率较为合适。     

Relationship between Arterial and Heated Skin Surface Carbon Dioxide Tension in Adults

Carbon dioxide tension was measured on heated skin surface (PSCO2) and in arterial blood (PaCO2) in eight adult patients during intermittent positive pressure ventilation. A total of 299 PaCO2-PSCO2 measurements were performed at electrode temperatures of 45 degrees C, 43 degrees C and 38 degrees C. The PSCO2-PaCO2 relation was evaluated using: 1) linear regression, 2) PSCO2/PaCO2 ratio and 3) temperature correction methods. Both linear regression and ratio indicate temperature dependency of the PSCO2-PaCO2 relation. The temperature correction method was done with a blood PCO2 temperature coefficient of 4.6% per degrees C and at two temperatures: electrode temperature (according to Severinghaus) and estimated capillary blood temperature. The results indicate that the relation between PaCO2, PSCO2 and electrode temperature is constant enough to permit estimation of PaCO2 from PSCO2 during stable circulatory conditions.     

CO2气腹对肿瘤细胞种植与生长的影响

目的　探讨腹腔镜手术中常用的气腹介质CO2 对径路口及腹腔内肿瘤细胞种植及转移的影响。方法　手术前 1h于 30只Wistar大鼠腹腔内注入R15肝癌细胞株 ,并按随机抽样法将大鼠均分为免气腹组、He气腹组和CO2 气腹组 3组 ,实验维持 2h、2 8d后宰杀动物 ,比较各组径路口及腹腔内肿瘤的种植及转移情况。结果　在径路口、肠浆膜层、肠系膜、大网膜和膈肌部位种植的肿瘤重量 :CO2 气腹组分别为 (32 6 .7± 2 30 .3)mg、(6 2 6 .2± 2 15 .9)mg、(476 .2± 2 0 4 .8)mg、(2 5 36 .5± 90 6 .7)mg及 (384 .5± 14 9.9)mg ;He气腹组分别为(2 35 .6± 10 7.3)mg、(414 .2± 14 8.4 )mg、(2 6 1.8± 92 .6 )mg、(16 33.4± 2 4 7.3)mg及 (2 2 0 .0± 5 7.9)mg ;免气腹组分别为 (14 5 .0± 4 2 .4 )mg、(2 2 1.5± 10 8.2 )mg、(2 12 .5± 10 9.6 )mg、(797.5± 335 .9)mg和 113.0mg。在各部位种植的肿瘤重量 ,CO2 气腹组均明显高于He气腹组和免气腹组 ,差异有显著性意义 (P<0 .0 5 ) ;He气腹组均高于免气腹组 ,但差异无显著性意义 (P>0 .0 5 )。结论　CO2 气腹与He气腹及免气腹相比 ,可促进腹腔内肿瘤细胞的种植与生长。     

The Effect on the Splanchnic Blood Flow and Cardiac Output of Various Carbon Dioxide Concentrations during Fluroxene (Fluoromar®) Anaesthesia An Animal Study

Seven dogs premedicated with pethidine 10 mg/kg body weight, were anaesthetized with mebumal natrium 25 mg/kg body weight i.v. and gallamoni jodidum 80 mg, together with O₂-N₂O in a ratio of 1 to 1. Thereafter four dogs were constantly hyperventilated and three constantly hypoventilated under stepwise increasing anaesthesia with fluoromar® (= fluroxene), up to 6% inspiratory concentration. A change was made between the groups at this fluoromar concentration, from hyper- to hypoventilation and vice versa, after which the fluoromar concentration was reduced stepwise to 0% inspiratory. During the course of this anaesthesia, the related values for flow, pressure and resistance in the systemic and splanchnic circulations were measured at fluoromar concentrations: 0–1 1/2–3-6-6-3-1 1/2-0%. The relative changes in the systemic circulation during increasing concentrations of fluoromar are independent of hypo- or hypercapnia, while the absolute magnitudes of the measured parameters are strongly dependent on the CO₂ tensions. The hypercapnic dogs had the highest cardiac output, stroke volume and most rapid pulse, as well as the lowest peripheral resistance. The same group of dogs had the lowest liver blood flow and the greatest splanchnic resistance. The mean pressures in the aorta, right atrium and portal vein were not different between the groups. A straight line dependence at 6% fluoromar, was demonstrated between cardiac index and Pa_co2: cardiac index (1-min^-1-m^-2) = 1.22 + 0.23 ± Pa_co2 (kPa), ((cardiac index (1-min^-1-m^-2) = 1.22 + 0.03 ± Pa_co2 (mmHg)), and peripheral resistance and Pa_o2: peripheral resistance (kPa 1^-1 min) = 12.85—0.5 ± Pa_co2 (kPa), ((peripheral resistance (dyn-sec-cm^-5 ± 10^-3) = 7.72-0.04 ± Pa_co2 (mmHg)). The pressure in the portal vein appears to rise and the liver flow to fall with rising carbon dioxide tension, but the relationship is not significant. In the latter half of the investigation only small changes were demonstrated which could be related to the falling concentration of fluoromar. These were slight rises in the mean pressure of the aorta and cardiac frequency, similar for both groups. In addition, a slight rise in the peripheral resistance and splanchnic resistance were observed in the hypocapnic group. No changes were seen in the cardiac output and liver flow in any of the groups during falling fluoromar concentrations. The absolute magnitude of the measured parameters in relation to the CO₂ tension reflects the conditions in the first half of the investigation, but the difference between the groups is less pronounced. This was partly due to the smaller difference in Pa_co2 between the groups in this part of the investigation and partly due to the time and experimental course.     

后腹腔镜CO2气腹对全麻患者血流动力学及血气的影响

目的 :探讨后腹腔镜手术CO2 气腹对全麻患者血流动力学及动脉血气的影响。方法 :选择后腹腔镜下行肾及肾上腺手术患者 2 0例 ,监测气腹前、气腹后 30、6 0min和放气后 30min血流动力学指标和动脉血气的变化。结果 :气腹后 30、6 0min患者平均肺动脉压 (mPAP)、肺小动脉楔压 (PAWP)和中心静脉压(CVP)均较气腹前显著增加。气腹前后心率、平均动脉压、心排指数 (CI)、体循环血管阻力指数 (SVRI)、肺血管阻力指数 (PVRI)和左心室收缩功能指数 (LVSWI)无显著性差异 (P >0 0 5 )。气腹后PaCO2 较气腹前明显增加 ,pH明显下降 (P <0 0 5 )。结论 :后腹腔镜CO2 气腹对全麻患者血流动力学和动脉血气有一定影响 ,术中需加强监测和管理。     

CO_2气腹对SD大鼠重症急性胰腺炎炎性细胞因子的表达及胰腺病理变化的影响

目的探讨腹腔镜手术时CO2气腹对SD大鼠重症急性胰腺炎(severe acute pancretitis,SAP)胰腺局部病变及血淀粉酶、炎症细胞因子IL-6、TNF-α、C-反应蛋白(C-reactive protein,CRP)及核转录因子-κB(NF-κB)的影响。方法雄性SD大鼠50只,随机分为3组:Ⅰ组20只(CO2组,5%牛磺胆酸钠胆胰管逆行注射方法建立SAP动物模型后,腹腔镜气腹机向大鼠腹腔内注入CO2,压力12mm Hg,维持30min);Ⅱ组20只(开腹组,建立SAP动物模型后关腹,不充入CO2);Ⅲ组10只(对照组,仅开腹翻动胰腺后关腹)。各组均于术后2.5h处死动物,测定血淀粉酶、IL-6、TNF-α及CRP的变化,进行胰腺组织病理学检查,并用免疫组化法检测NF-κB的变化。结果Ⅰ、Ⅱ、Ⅲ组病理组织学评分值分别为(1.90±0.37)分、(1.75±0.26)分、(0.00±0.00)分,差异有统计学意义(F=365.91,P=0.000),但Ⅰ组与Ⅱ组比较,差异无统计学意义(q=2.372,P0.05)。与Ⅲ组相比,Ⅰ组和Ⅱ组血清淀粉酶、IL-6、TNF-α均明显升高(P0.05)。与Ⅱ组相比,Ⅰ组IL-6降低(P0.05),淀粉酶明显升高(P0.05),Ⅰ组与Ⅱ组TNF-α、CRP差异无统计学意义(P0.05)。Ⅰ、Ⅱ组与Ⅲ组NF-κB阳性表达值分别为3.91±0.81、3.55±0.76、0.92±0.51,差异有显著性(F=56.59,P=0.000),Ⅰ组与Ⅱ组比较,NF-κB表达差异有统计学意义(q=3.387,P0.05),Ⅰ、Ⅱ组与Ⅲ组比较,NF-κb阳性表达值有显著性差异(q=14.764,P0.05;q=11.999,P0.05)。结论CO2气腹对SD大鼠SAP胰腺病理变化无明显影响。SAP时CO2气腹对SD大鼠TNF-α、CRP的表达无明显影响,对IL-6的表达有一定的抑制作用,能增强NF-κB阳性表达。     

The Effect of Tourniquet Use and Sterile Carbon Dioxide Gas Bone Preparation on Cement Penetration in Primary Total Knee Arthroplasty

BackgroundTourniquetless total knee arthroplasty (TKA) is experiencing resurgence in popularity due to potential pain control benefits. Furthermore, optimal cement technique and implant fixation remain paramount to long-term cemented TKA success, as aseptic loosening continues to be a leading cause of revision. The purpose of this study is to determine how tourniquet use and/or novel bone preparation using sterile, compressed carbon dioxide (CO₂) gas affected cement penetration in TKA.MethodsA retrospective review was performed on 303 consecutive primary TKAs with the same implant in 3 groups: (1) a tourniquet without sterile CO₂ compressed gas used for bone preparation, (2) no tourniquet with CO₂ gas, and (3) tourniquet use and CO₂ gas bone preparation. Cement penetration was measured on radiographs by two independent, blinded raters across 7 zones defined by the Knee Society Radiographic Evaluation System.ResultsThe 3 groups did not differ on age, body mass index, or gender (P ≥ .1). Cement penetration was greater in 6 of 7 zones with significantly greater cement penetration in 3 zones (tibial anteroposterior zone 2, femoral lateral zones 3A and 3P) in groups that utilized CO₂ gas bone preparation compared to the tourniquet only group (P ≤ .039).ConclusionBone prepared with CO₂ gas showed significantly more cement penetration in 3 zones with greater cancellous bone. The results suggest that use of CO₂ gas bone preparation may achieve greater cement penetration than using a tourniquet with lavage only.     

CO_2气腹对大鼠重症急性胰腺炎胰腺病理及IL-1、IL-6、CD11a/CD18和CD11b/CD18的影响

目的研究腹腔镜手术时CO2气腹对Sprague-Dawley(SD)大鼠重症急性胰腺炎(SAP)胰腺组织病理学改变、血淀粉酶、炎症细胞因子(IL-1和IL-6)和可溶性黏附分子(CD11a/CD18和CD11b/CD18)的影响。方法雄性SD大鼠50只,随机分为3组:CO2气腹组(n=20),5%牛磺胆酸钠胆胰管逆行注射方法制备SAP动物模型后,以气腹机向大鼠腹腔内注入CO2〔压力12mmHg(1mmHg=0.133kPa),维持30min〕;SAP组(n=20):建立SAP模型后关腹,不充入CO2;单纯手术组(n=10):仅开腹翻动胰腺后关腹。各组均于术后2.5h处死动物,取静脉血测定血淀粉酶、IL-1和IL-6水平及CD11a/CD18和CD11b/CD18的表达阳性率,并进行胰腺组织病理学检查。结果与单纯手术组相比,CO2气腹组和SAP组胰腺组织病理学评分、血清淀粉酶、IL-1和IL-6水平及CD11a/CD18和CD11b/CD18表达阳性率均明显升高,差异有统计学意义(P=0.000)。与SAP组相比,CO2气腹组血IL-1和IL-6水平明显降低,差异有统计学意义(P=0.000);而胰腺组织病理学评分(P=0.294)、血清淀粉酶水平(P=0.073)、CD11a/CD18(P=0.155)和CD11b/CD18(P=0.201)表达阳性率的差异无统计学意义。结论对于SAP大鼠,CO2气腹对IL-1和IL-6水平有一定的抑制作用;而对胰腺病理变化及CD11a/CD18和CD11b/CD18表达阳性率无明显影响。     

二氧化碳气腹下行胆囊切除术对胃粘膜二氧化碳分压及pH的影响

目的：探讨腹腔镜二氧化碳气腹对胃粘膜二氧化碳分压（i-PCO2)及胃粘膜pH(i-pH)的影响。方法：选择20例二氧化碳气腹下胆囊切除术病人。采用胃管法，分别于气腹前，气腹20、40分钟，排气后30分钟抽取胃液3－5ml。分析胃液PCO2及PO2，同时在气腹前、后各时点监测动脉血PaCO2,PaO2,pH,HCO3^-和BE，并代入Henderson-Hasseibach公式，计算i-pH。结果：i-PCO2在气腹20分钟腹前有显著性升高（P＜0．05）（气腹40分钟，排气后30分钟与气腹前比较显著升高（P＜0．01），气腹20、40分钟，排气后，30分钟i-pH均较气腹前明显降低（P＜0．01）。气腹40分钟时，i-PCO2最高，而i-pH为最低。胃粘膜氧分压（i-PO2)气腹前、后无明显变化，PaCO3气腹40分钟、排气后30分钟均显著高于气腹前（P＜0．01），动脉血pH、BE气腹后各时点均较气腹前降低（P＜0．01）。动脉血PaO2,HCO3^-气腹前后变化不明显（P＞0．05）。结论：二氧化碳气腹下胃粘膜有缺血低灌注现象。随着气腹时间延长，胃粘膜低灌注，酸中毒的症状加重。     

悬吊式、气腹腹腔镜及不同麻醉方法对妇科患者细胞因子水平的影响

目的 比较在不同麻醉方法下妇科悬吊式或气腹腹腔镜患者术中血清细胞因子白介素-6(IL-6)、白介素-10(IL-10)、肿瘤坏死因子-α(TNF-α)和热休克蛋白70(heat shock protein 70,HSP70)水平的变化.方法 选择57例择期行腹腔镜下子宫肌瘤剔除术的患者,手术时间均短于100 min,按手术方式或患者的意愿分成3组(每组19例):Ⅰ组,于静脉全麻下行CO2气体腹腔镜手术;Ⅱ组,于静脉全麻下行悬吊式腹腔镜手术;Ⅲ组,于硬膜外神经阻滞麻醉下行悬吊式腹腔镜手术.监测3组患者麻醉前(T1)、气腹或悬吊建立后30 min(T2)、气腹或悬吊撤除后10 min(T3)和术后第2天晨8时(T4)4个时点的TNF-α、IL-6、IL-10和HSP70浓度.结果 麻醉前患者的血清IL-6、IL-10、TNF-α和HSP70水平差异均无统计学意义(P＞0.05).术后各指标的水平均升高,其中Ⅰ组在T3时达峰值,Ⅱ组和Ⅲ组在T4时达峰值.组间比较,Ⅰ组在T2时点的TNF-α水平[(31±14) pg/L)]高于Ⅱ组[(24±10) pg/L] (P＜0.05);在T3时点,Ⅰ组的IL-6[ (46±8) pg/L]、TNF-α[( 54±18) pg/L]和HSP70[ (3.18±0.58) μg/L]水平分别显著高于Ⅱ组[( 39±6) pg/L,(36±17) pg/L,(2.30±0.29) μg/L](P＜0.叭),且IL-6/IL-10比值也高于Ⅱ组(P＜0.05);此时,Ⅲ组的IL-6[(27±10) pg/L]和TNF-α[(24±7)pg/L]水平低于Ⅱ组(P＜0.05).结论 悬吊式腹腔镜技术免除了CO2气腹对机体的影响,降低了术中应激反应水平,与全身麻醉相比,硬膜外麻醉可进一步减轻此术式引起的应激反应.     

Correlations Between Brain Tissue Oxygen Tension, Carbon Dioxide Tension, pH, and Cerebral Blood Flow-A Better Way of Monitoring The Severely Injured Brain?

Background

The ideal method for monitoring the acutely injured brain would measure substrate delivery and brain function continuously, quantitatively, and sensitively. We have tested the hypothesis that brain pO₂, pCO₂, and pH, which can now be measured continuously using a single sensor, are valid indicators of regional cerebral blood flow (CBF) and oxidative metabolism, by measuring its product, brain pCO₂.

Methods

Twenty-five patients (Glasgow Coma Score ≤ 8) were studied. A Clark electrode, combined with a fiber optic system (Paratrend 7, Biomedical Sensors, Malvern, PA) was used to measure intraparenchymal brain pO₂, pCO₂, and pH. Data were averaged over a 1-h period before and after CBF studies. Regional CBF was measured around the probe, using stable xenon computed tomography. Regression analyses and Spearman Rank tests were used for data analysis.

Results

Regional CBF and mean brain pO₂ were strongly correlated (r = 0.74, p = 0.0001). CBF values < 18 mL/100 g/min were all accompanied by brain pO₂ ≤ 26 mm Hg. The four patients with a brain pO₂ < 18 mm Hg died. Brain pCO₂ and pH, however, were not correlated with CBF (r = 0.36, p = 0.24 and r = 0.30, p = 0.43, respectively).

Conclusions

Until recently, substrate supply to the severely injured brain could only be intermittently estimated by measuring CBF. The excellent intra-regional correlation between CBF and brain pO₂, suggests that this method does allow continuous monitoring of true substrate delivery, and offers the prospect that measures to increase O₂ delivery (e.g., increasing CBF, CPP, perfluorocarbons etc.) can be reliably tested by brain pO₂ monitoring.     

The Heartmate II: design and development of a fully sealed axial flow left ventricular assist system

Our group is developing the control and power transmission components required to implement a permanent and fully sealed left ventricular assist system (LVAS). Starting with the percutaneously powered HeartMate II blood pump, our development efforts are focused in the following areas: a complete redesign of the transcutaneous energy transmission system (TETS) to include a rectification network and autonomous voltage regulation within the secondary coil, a hermetically sealed electronics package containing a miniaturized implementation of the existing redundant drive and control electronics with several power-input options, an implanted rechargeable lithium ion battery pack capable of providing up to 1 h of untethered operation, implantable electrical connectors that allow components to be connected after placement in the body or to be replaced if needed, and a radio telemetry subsystem to transmit diagnostic information and to permit remote adjustment of selected parameters.