Skin oxygenation after topical application of liposome-entrapped benzyl nicotinate as measured by EPR oximetry in vivo: Influence of composition and size

New and improved drug delivery systems are the important subject of much scientific research. The development of formulations that increase skin oxygenation and of methods for measuring oxygen levels in skin are important for dealing with healing processes affected by the level of oxygen. We have use EPR oximetry in vivo to compare the influence of liposomal formulations of different size and composition with that of hydrogel with respect to the action of the entrapped benzyl nicotinate (BN). Following the topical application of BN onto the skin of mice, pO₂ increase was measured by low-frequency EPR as a function of time. The effect of BN was evaluated by 3 different parameters: lag-time, time needed for maximum pO₂ increase, and overall effectiveness expressed by the area under the response-time curve. An increase in skin oxygenation was observed after BN application. The results show that the effect of BN incorporated in liposomes is achieved more rapidly than the effect from hydrophilic gel. The composition of the liposomes significantly affects the time at which BN starts to act and, to a lesser extent, the maximum increase of pO₂ in skin and the effectiveness of BN action. However, the size of the liposomes influences both the effectiveness of BN action and the time at which BN starts to act. After repeated application of liposomes, the pO₂ baseline increased and the response of the skin tissue was faster. Our results demonstrate that EPR oximetry is a useful method for evaluating oxygen changes after drug application and for following the time course of their action.     

Resuscitation and circulatory support using extracorporeal membrane oxygenation for fulminant pulmonary embolism

Fulminant pulmonary embolism (PE) with circulatory collapse is associated with a high mortality rate due to acute right ventricular failure and hypoxia. Immediate and appropriate resuscitation and circulatory support in the perioperative period is mandatory to prevent sudden death. Extracorporeal membrane oxygenation (ECMO) was recently introduced for extracorporeal life support in patients with circulatory collapse and has provided an excellent outcome. We report on the effectiveness of ECMO support for fulminant PE. Seven patients were placed on veno-arterial ECMO for circulatory collapse caused by fulminant PE refractory to conventional treatment. After resuscitation, all patients underwent pulmonary angiography, and thrombolytic therapy was administered in all 7 patients under ECMO support. Three patients who did not improve by thrombolysis underwent embolectomy with standard cardiopulmonary bypass. Two thrombolysis and 2 surgery patients were weaned from bypass and survived. The duration of support ranged from 18-168 h (mean = 67.8 +/- 67.1 h), with maximum bypass flow rates of 2.0-4.5 (mean = 3.5 +/- 0.9). There were no device-related complications during support. In total, 4 patients (57%) were successfully weaned from support and discharged from the hospital in good condition. All patients who survived required prolonged support (27, 82, 151, and 168 h). We conclude that resuscitation and circulatory support using ECMO can be effective, life-saving measures in cases of circulatory collapse caused by fulminant PE.     

高压氧治疗对脑外伤患者血糖影响的比较研究

目的 探讨高压氧治疗对脑外伤患者血糖的影响。方法 将100例脑外伤患者随机分为治疗组和对照组，分别测量治疗前后两组患者血糖浓度。结果 高压氧治疗后脑外伤患者血糖浓度较对照组明显降低。结 论高压氧治疗能使脑外伤后升高的血糖降低，促进受损伤脑组织修复。     

高压氧与纳洛酮治疗急性一氧化碳中毒的研究

目的　观察比较早期采取高压氧与纳洛酮治疗急性一氧化碳 (CO)中毒的疗效。方法　将 4 5例急性CO中毒患者随机分为高压氧组和纳洛酮组 ,2组患者均给予常规治疗 ,高压氧组待患者生命体征平稳后即给予高压氧治疗 ,纳洛酮组患者入院时即给予纳洛酮治疗。观察 2组患者昏迷时间、症状消失时间、脑电图 (EEG)变化及迟发性脑病发生率 ,测定治疗前与完全清醒后动脉血气。结果　 2组患者的昏迷时间、症状消失时间及迟发性脑病发生率均无显著性差异 (P >0 .0 5 )。纳洛酮组EEG阳性率明显高于高压氧组 (P <0 .0 5 ) ,p(O2 )和Sa(O2 )上升值明显低于高压氧组 (P <0 .0 5 )。结论　高压氧和纳洛酮均可以有效缩短急性CO中毒患者的昏迷时间 ,改善患者症状 ,降低迟发性脑病的发生率 ,故在无条件进行高压氧治疗时 ,早期使用纳洛酮也不失为一种有效的治疗方法     

Comparison of combined spinal epidural anesthesia and epidural anesthesia for cesarean section

BACKGROUND: Epidural anesthesia (EA) is popular for cesarean section, but has some drawbacks such as incomplete block, inadequate muscle relaxation and delayed onset. Combined spinal epidural anesthesia (CSEA) has gained increasing interest as it combines the reliability of a spinal block and the flexibility of an epidural block. We investigated the efficacy of CSEA that combines the main spinal and the supporting epidural anesthesia, comparing with pH-adjusted EA, for cesarean section. METHODS: Sixty-four pregnant women at full term were divided into two groups. Patients in the CSEA group (n=32) were given 1.5-1.6 ml of 0.5% hyperbaric bupivacaine intrathecally, followed by 10 ml of 0.25% plain bupivacaine through the epidural catheter 10 min later. Patients in the EA group (n=32) received 20-25 ml of 2% lidocaine which was already mixed with 0.1 ml of 0.1% epinephrine, 100 g of fentanyl and 1.5 ml of 8.4% sodium bicarbonate. The quality and side effects of surgical anesthesia, neonatal state, and postoperative course were compared between the two groups. RESULTS: In the EA group, 22% (7 cases) complained of intraoperative pain but none in the CSEA group (P=0.011). Muscle relaxation and motor block were much better in the CSEA group (P<0.001 and P=0.011 each). Significantly more women in the EA group had shivering (P=0.001). They also had more nausea and vomiting but the differences were not significant. Not only the time to T4 block (9.7 vs. 18.3 min, mean, P<0.001) but also the stay in the postanesthesia care unit, recovery of sensory and motor block and start of postoperative pain were all significantly shorter in the CSEA group. No one in either group had postdural puncture headache (PDPH). CONCLUSION: We can conclude that, when combining the main spinal and the supporting epidural anesthesia, CSEA has greater efficacy and fewer side effects than the pH-adjusted EA in cesarean sections.     

微机在高压氧舱中的应用

利用微机及其附属设备，实现高压氧舱操作全过程氧浓度监控的自动化。     

高压氧对缺氧缺血性脑损伤新生大鼠不同时期的影响

目的观察不同时期高压氧(HBO)对大鼠缺氧缺血性脑损伤(HIBD)模型的治疗疗效,分析其机制。方法32只7日龄Wistar大鼠制成HIBD模型,随机分为HIBD组(n=12)、HBO早治组(n=12)、HBO晚治组(n=8),并设假手术组(n=12)。HBO早治组与晚治组分别于造模后4 h1、4 d应用HBO。各组动物(除HBO晚治组)于14日龄治疗结束后各处死6只,余同HBO晚治组喂养至28日龄,避暗法测试学习记忆能力后于30日龄处死。以脑组织海马CA1区形态学及学习记忆能力来判断干预效果。结果(1)HE染色:HIBD组各时间点左侧大脑海马CA1区锥体细胞排列紊乱、疏松,层次不清,与假手术组及HBO早治组差异明显;HBO晚治组与HIBD组相似,但神经元数目较之多。(2)微管相关蛋白(MAP-2)灰度值免疫组化定量:HIBD组不同时间点MAP-2阳性表达不同程度下降,与假手术组及HBO早治组差异显著(P<0.01);HBO晚治组也较假手术组及早治组下降(P<0.01),但较HIBD组表达多(P<0.05)。(3)学习记忆能力测试:HIBD组较假手术组明显下降(P<0.05),而HBO早治组与晚治组均高于HIBD组。结论不论早期或晚期应用HBO治疗均能不同程度地减轻HIBD所致的海马CA1区组织学损伤,改善由HIBD引起的学习记忆能力下降,但早期治疗明显优于晚期治疗。     

Assistance respiratoire veino-veineuse et assistance circulatoire veino-artérielle avec oxygénation extracorporelle. Questions,réponses

A round table, organized by the French Society of Perfusion (Sofraperf) at the French national congress on extracorporeal circulations (Perfusion 2013), was attended by perfusionists, anaesthesiologists, intensivists and surgeons around the theme of respiratory veno-venous support and veno-arterial circulatory support with extracorporeal oxygenation in intensive care units. The debate was conducted in a participatory manner by bi-directional questions–answers session between moderators and assistance. The authors report management of this type of therapy that is not perfectly homogeneous, supported on literature data. Cannulae, cannulation, circuit, oxygenator, anticoagulation, control, surveillance, weaning are subject to paragraphs with defined entry whose contents are mutually enriching.     

Pathophysiological and vascular characteristics of tumours and their importance for hyperthermia: Heterogeneity is the key issue

Tumour blood flow before and during clinically relevant mild hyperthermia exhibits pronounced heterogeneity. Flow changes upon heating are not predictable and are both spatially and temporally highly variable. Flow increases may result in improved heat dissipation to the extent that therapeutically relevant tissue temperatures may not be achieved. This holds especially true for tumours or tumour regions in which flow rates are substantially higher than in the surrounding normal tissues.

Changes in tumour oxygenation tend to reflect alterations in blood flow upon hyperthermia. An initial improvement in the oxygenation status, followed by a return to baseline levels (or even a drop to below baseline at high thermal doses) has been reported for some tumours, whereas a predictable and universal occurrence of sustained increases in O₂ tensions upon mild hyperthermia is questionable and still needs to be verified in the clinical setting. Clarification of the pathogenetic mechanisms behind possible sustained increases is mandatory.

High-dose hyperthermia leads to a decrease in the extracellular and intracellular pH and a deterioration of the energy status, both of which are known to be parameters capable of acting as direct sensitisers and thus pivotal factors in hyperthermia treatment. The role of the tumour microcirculatory function, hypoxia, acidosis and energy status is complex and is further complicated by a pronounced heterogeneity. These latter aspects require additional critical evaluation in clinically relevant tumour models in order for their impact on the response to heat to be clarified.