Thoracic epidural anesthesia increases mucosal perfusion in ileum of rats

BACKGROUND: Previous studies reported that thoracic epidural anesthesia (TEA) protected against a decrease in gastric intramucosal pH, suggesting that TEA increased gut mucosal perfusion. The current study examines the effects of TEA on ileal mucosa using intravital microscopy in anesthetized rats. METHODS: Nineteen rats were equipped with epidural catheters, with the tip placed at T7 through T9. Rats were anesthetized and mechanically ventilated. After midline abdominal incision, the ileum was prepared for intravital microscopy. Videomicroscopy on the ileal mucosa was performed before and after epidural infusion of 20 microliter of bupivacaine 0.4% (TEA group, n = 11 rats) or normal saline (control group, n = 8 rats). Microvascular blood flow in ileum mucosa was assessed offline using computerized image analysis. RESULTS: Control rats exhibited unchanged mean arterial pressure and microvascular perfusion. During TEA, mean arterial pressure was decreased compared with the control group (93 +/- 10 vs. 105 +/- 9 mmHg; P < 0.05). Epidural bupivacaine increased red cell velocity in terminal arterioles from 888 +/- 202 to 1,215 +/- 268 micrometer/s (control, 793 +/- 250 to 741 +/- 195 micrometer/s; P < 0.001 between groups). Because arteriolar diameter was not affected, this increase in red cell velocity may represent an increase in arteriolar blood flow. Total intercapillary area (inversely related to perfused capillary density) was unchanged, but for the TEA group the difference between total intercapillary area and the intercapillary area calculated for continuously perfused capillaries was decreased compared with the control group (16 +/- 12 vs. 40 +/- 19%; P < 0.001), indicating a decrease in intermittent (stop-and-go) blood flow in the villus microcirculation. CONCLUSION: Thoracic epidural anesthesia increased gut mucosal blood flow and reduced intermittent flow in the villus microcirculation in the presence of a decreased perfusion pressure.     

Thoracic epidural analgesia improves lung function in CABG patients

Canadian Journal of Anesthesia/Journal canadien d'anesthésie -     

Thoracic epidural analgesia improves pulmonary function in patients undergoing cardiac surgery

PURPOSE: Pulmonary dysfunction commonly occurs following coronary artery bypass graft (CABG) surgery, increasing morbidity and mortality. We hypothesized that thoracic epidural anesthesia (TEA) would improve pulmonary function and would decrease complications in patients undergoing CABG surgery. METHODS: This prospective, randomized, controlled trial was conducted with Ethics Board approval. Fifty patients, undergoing CABG surgery, were randomized to the epidural group or to the patient-controlled analgesia morphine group. Patients in the epidural group received a high, thoracic epidural, preoperatively. Intraoperatively, 0.75% ropivacaine was infused, followed postoperatively, by 0.2% ropivacaine for 48 hr. Outcome measurements included: visual analogue pain scores; spirometry; atelectasis scores on chest radiographs; and the incidence of atrial fibrillation. RESULTS: Twenty-five patients were enrolled in each group. Patients in the epidural group had significantly less pain on the operative day, and for the subsequent two days. Compared to baseline, the forced expiratory volume in one second was significantly higher in the epidural group, on the first and second postoperative days (43.7 +/- 12.2% vs 36.4 +/- 12.0%, p < 0.002, and 43.3 +/- 12.5% vs 38.4 +/- 11.0%, p <0.05). There was significantly more atelectasis in the control group, four hours postoperatively (p < 0.04); however, on the third, postoperative day, the groups were similar with regards to this outcome. The incidence of atrial fibrillation was similar in both groups, and there were no complications related to the epidural. CONCLUSIONS: High TEA decreases postoperative pain and atelectasis and improves pulmonary function in patients undergoing CABG surgery. Our results support the use of TEA in this group of patients.     

Thoracic epidural anaesthesia and analgesia

Thoracic epidural anaesthesia followed by postoperative epiduralanalgesia is increasingly being used for abdominal, major vascularand cardiothoracic surgery. The objective of thoracic blockis not solely to block noxious afferent stimuli from the surgicalsite, but to impart a bilateral selective thoracic sympathectomy.Provision of pain relief and sympatholysis of such magnitudethat allows patients to cough, breath deeply, drink and mobilizecan contribute to enhanced postoperative outcomes such as improvedrespiratory function, reduction in ileus and protein sparing.The challenge is how to translate the encouraging results ofrandomized controlled studies and meta-analyses into clinicalpractice. Provision of sufficient intraoperative epidural anaesthesiasuch that the patient awakes pain-free and maintenance of acontinuous bilateral sensory block covering the entire surgicalsite for several days is not an easy task. The aim of this reviewis to discuss the practical issues related to thoracic epiduralanalgesia.     

Thoracic epidural anesthesia attenuates hemorrhage-induced impairment of intestinal perfusion in rats

BACKGROUND: During hemorrhagic hypotension, sympathetic vasoconstriction crucially contributes to gut mucosal damage. Sympathetic blockade by thoracic epidural anesthesia has been shown to increase mucosal microvascular perfusion and to improve survival after severe hemorrhage in laboratory animals. This study investigates the effects of thoracic epidural anesthesia on intestinal microvascular perfusion during hemorrhagic hypotension in rats. METHODS: In 32 anesthetized Sprague-Dawley rats either lidocaine 2% (thoracic epidural anesthesia) or normal saline (control) was infused via thoracic epidural catheters. Hemorrhagic hypotension (mean arterial pressure 30 mmHg for 60 min) was induced by withdrawal of blood, which was subsequently retransfused for resuscitation. Functional capillary density and erythrocyte velocity in the mucosa and muscularis were determined by intravital microscopy. Leukocyte-endothelium interaction was studied in postcapillary venules and sympathetic nerve fibers of the intestinal wall were identified by immunohistochemistry. RESULTS: During hypotension functional capillary density was significantly (P < 0.001) lower in the muscularis of the control group (median [25/75 percentile]: -46.5% [-59.6/-20.8%] change from baseline) as compared with animals that received thoracic epidural anesthesia (-6.1% [-13.4/1.1%]). There were no differences in erythrocyte velocity between groups throughout the experiment. Leukocyte rolling increased significantly (P < 0.001) after resuscitation in control (12 [6/15] vs. baseline 2.5 [1/8]) but not in thoracic epidural anesthesia (4 [2.3/7] vs. baseline: 5 [3/15.5]). Sympathetic nerve fibers were identified in the muscularis and submucosa but not in the mucosa. CONCLUSIONS: During hemorrhagic hypotension and after resuscitation, thoracic epidural anesthesia has beneficial effects on intestinal microvascular perfusion. Because of blockade of sympathetic nerves, thoracic epidural anesthesia prevents perfusion impairment of the muscularis during hypotension and attenuates leukocyte rolling after resuscitation.     

Thoracic epidural analgesia and the cardiovascular system

Thoracic epidural exerts a remarkable influence on the cardiovascular system (Table 1). With regard to cardiac electrical activity in animal models, TEA was found to lengthen repolarization and to protract the refractory period more at the ventricular site than at the atrium. The atrio-ventricular conduction and refractoriness are also prolonged. Human studies documented a slight impairment in the sensitivity of the baroreflexes sparing the sympathetically mediated responses to various stress if TEA is limited to the first five thoracic vertebrae. Although an overall reduced risk of perioperative dysrhythmias, TEA is not shown to decrease the incidence of postoperative atrial fibrillation.There are contradictory results from animal studies on the effect of TEA on ventricular function. In healthy patients, TEA seems to alter left ventricular contractility and reduce cardiac output, whereas in cardiac surgical patients, the left ventricular global and regional wall motion were better preserved.In a canine model, TEA improves regional blood flow by favoring the endocardium. In patients, TEA has been associated with a reduction of the major determinants of cardiac oxygen consumption without jeopardizing coronary perfusion pressure and even increasing the diameter of stenotic coronary segments. Thus, TEA lessens the severity of experimental acute myocardial ischemic injury and quickens the recovery after brief ischemic insult. In patients, changes in clinical markers of ischemic damage, such as Troponin T and Atrial Natriuretic Peptide, are not consistent, except for Brain Natriuretic Peptide, which is diminished. The overall incidence of myocardial infarction is also reduced.TEA produces functional hypovolemia by inhibiting the vasoconstrictor sympathetic outflow, oreover it interferes with the integrity of renin–angiotensin system, but increments vasopressin plasma concentration. Although TEA causes hypotension, it has a beneficial outcome during hemorrhagic shock.     

乌司他丁对重症急性胰腺炎大鼠脑毛细血管渗漏的影响

胰性脑病是重症急性胰腺炎(SAP)的严重并发症,与大脑的毛细血管渗漏紧密相关.occludin蛋白是脑组织重要的紧密连接蛋白,与大脑毛细血管通透性密切相关.乌司他丁(UTI)是一种广谱的蛋白酶抑制剂,已经广泛用于临床,但其对胰性脑病的治疗及机制研究甚少.本研究旨在探讨occludin在SAP大脑毛细血管渗漏中的作用及UTI治疗胰性脑病的作用机制.     

Thoracic epidural anaesthesia and analgesia for abdominal surgery: effects on gastrointestinal function and perfusion

Post-operative ileus constitutes a major morbidity after abdominal surgery. While systemic opioid analgesia is thought to interfere with gastrointestinal function, epidural anaesthesia and analgesia can theoretically speed resolution of ileus. This chapter reviews the pathophysiology of post-operative ileus and the experimental and clinical literature which investigates the effects of epidural therapy on gastrointestinal motility and blood flow. The risks of epidural therapy, including the potential stress on fresh colonic anastomoses, are also discussed. Emphasis is placed on the inclusion of local anaesthetics in the epidural analgesic solution and on the vertebral level of epidural catheter placement. Epidural anaesthesia–analgesia targeted to the thoracic and high lumbar spine congruent to the abdominal incision appears to shorten the duration of ileus after abdominal surgery without undue risk to the patient. However, length of hospital stay is not decreased unless fast-track management is implemented.     

Endothelin receptor blockade improves fluid sequestration, pancreatic capillary blood flow, and survival in severe experimental pancreatitis.

OBJECTIVE: To evaluate the effect of a new endothelin receptor antagonist (ET-RA) on the course of severe experimental pancreatitis. BACKGROUND: Endothelin-1 has been shown to reduce regional blood flow in various organs, including the pancreas, and to aggravate cerulein-induced mild pancreatitis. METHODS: Acute necrotizing pancreatitis (ANP) was induced in rats by standardized intraductal bile acid infusion and cerulein hyperstimulation. Serum trypsinogen activation peptides (TAP) were measured to verify comparable disease severity. Starting 6 hours after the onset of ANP, animals randomly received either saline or the new ET-RA LU-135252. Monitoring included cardiorespiratory parameters, urine output, hematocrit, and TAP levels. After 24 hours, animals were relaparotomized to determine pancreatic capillary blood flow and to assess the amount of free intraabdominal fluid and acinar cell necrosis. Survival was determined in a second set of experiments on 24 animals observed for 48 hours after pancreatitis induction and treatment with either normal saline or ET-RA. RESULTS: Comparable TAP increases confirmed equally severe ANP in both groups before treatment. Treatment with ET-RA significantly reduced the mortality rate, from 50% in untreated animals to 8%. Improved survival was associated with significantly decreased hematocrit, improved urinary output, decreased ascites, and increased pancreatic capillary blood flow. There were no significant differences in plasma TAP and acinar cell injury in the surviving animals of the two treatment groups. CONCLUSION: Therapy with the new ET-RA reduces the early mortality rate in experimental ANP, probably by reducing fluid sequestration and improving microcirculation.     

急性重症胰腺炎肠粘膜屏障功能改变的临床研究

目的:探讨急性重症胰腺炎(SAP)时肠粘膜屏障功能改变机制.方法:20例SAP入院当天采血检测二胺氧化酶(DAO)、内毒素(endotoxin,ET)、肿瘤坏死因子(TNFα)、一氧化氮(NO)的浓度.并用带特殊电化学检测器的高压液相色谱法(HPLC)检测尿中乳果糖与甘露醇排泄率比值.以10名健康志愿者作为正常对照组.结果:同正常对照组相比较,SAP患者尿中乳果糖与甘露醇排泄率比值明显升高(P＜0.01);血中ET、NO、TNFα、DAO的水平显著增加(P＜0.01).结论:在急性重症胰腺炎患者中,肠粘膜屏障受损,肠粘膜通透性增高.ET、NO、TNFα单独或协同参与肠粘膜屏障的损害.DAO可反映肠道粘膜的完整性.     

肠黏膜屏障功能障碍在重症急性胰腺炎中的研究进展

重症急性胰腺炎(SAP)病情险恶、并发症多,且病死率高。过去几十年来,SAP发病率显著增加,SAP可导致肠道黏膜屏障损伤,从而引起细菌或内毒素易位,继而出现胰腺组织继发感染,导致全身炎症反应综合征(SIRS)及多器官功能障碍综合征,进而影响SAP患者的预后。在SAP发病过程中肠黏膜屏障损伤具有重要作用。因此,对肠道黏膜屏障功能障碍在SAP发病机制研究中尤为重要。现将重症急性胰腺炎肠黏膜屏障功能障碍的研究进展进行综述。     

重症急性胰腺炎区域动脉灌注的序贯治疗选择

自武田和宪报告区域动脉灌注(RAI)治疗急性坏死性胰腺炎至今已历经16年[1],目前RAI作为治疗重症急性胰腺炎(SAP)的一种增效非手术方法正逐渐被胰腺外科所接受.     

重症急性胰腺炎区域动脉灌注的序贯治疗选择

自武田和宪报告区域动脉灌注(RAI)治疗急性坏死性胰腺炎至今已历经16年[1],目前RAI作为治疗重症急性胰腺炎(SAP)的一种增效非手术方法正逐渐被胰腺外科所接受.     

重症急性胰腺炎区域动脉灌注的序贯治疗选择

自武田和宪报告区域动脉灌注(RAI)治疗急性坏死性胰腺炎至今已历经16年[1],目前RAI作为治疗重症急性胰腺炎(SAP)的一种增效非手术方法正逐渐被胰腺外科所接受.     

Thoracic epidural versus patient-controlled analgesia in elective bowel resections

BACKGROUND: This study was undertaken to determine if thoracic epidural analgesia is of practical benefit after bowel resection. METHODS: Patients were prospectively randomized to receive either a thoracic epidural or patient-controlled analgesia for pain control after bowel resection. A standardized postoperative protocol was instituted after surgery. RESULTS: Pain scores were significantly lower in the epidural group. Return of bowel function, and interval to discharge was not different between groups. Cost and complication rates were significantly higher in the epidural group. CONCLUSIONS: Although pain scores were significantly lower in the epidural group, this did not translate into a quicker return of bowel function or earlier discharge of the patient. Furthermore, the epidural group had a significantly higher complication rate and cost. Therefore, while thoracic epidural analgesia provides superior pain control, it does not offer a significant advantage over patient-controlled analgesia in return of bowel function after bowel resection.     

Thoracic epidural anaesthesia and analgesia: United Kingdom practice

BACKGROUND: Thoracic epidural analgesia has become increasingly practised in recent years. Complications are rare but potentially serious and, consequently, careful evaluation is required before undertaking this technique. The practice surrounding this procedure varies widely amongst anaesthetists. METHODS: A postal survey to examine the practice of thoracic epidural analgesia was sent to all Royal College of Anaesthetists tutors in the United Kingdom. RESULTS: Responses were received from 240 tutors, representing a return rate of 83%. When obtaining consent for thoracic epidural cannulation, 42% of respondents mentioned risk of a dural tap complication and 11% mentioned neurological damage. Fifty percent of respondents performed epidural cannulation following induction of general anaesthesia. The practice of epidural insertion in patients with abnormal coagulation varied, although over 80% of respondents did not consider concurrent treatment with either aspirin or non-steroidal anti-inflammatory drugs a contraindication. Sterile precautions for epidural insertion also varied between anaesthetists. Postoperatively, 95% of respondents used an opioid-based bupivacaine solution for epidural infusions, and these were most commonly nursed on general surgical wards (63%). Seventy-eight percent of hospitals provided an acute pain team to review epidural analgesia. CONCLUSION: In the United Kingdom, there is little consensus in the practice of thoracic epidural analgesia relating to the issues of informed consent, epidural cannulation in patients with deranged clotting and the sterile precautions taken prior to performing epidural insertion. Most respondents use an opioid-based bupivacaine solution to provide postoperative epidural analgesia. Most hospitals in the UK now provide an acute pain service for thoracic epidural follow-up.     

保留导管区域灌注在治疗重症脂源性胰腺炎中的应用

【摘要】〓目的〓评价经供胰腺血管留置导管持续灌注疗法(CRAI)治疗重症脂源性胰腺炎的疗效。方法〓选择2013年1月至2016年5月期间纳入的43例患者重症脂源性胰腺炎患者,包括区域灌注组(23例)和常规治疗组(20例),分析对比白细胞计数﹑血清淀粉酶﹑尿淀粉酶﹑APACHE-Ⅱ、血糖值﹑血钙值变化情况;比较两组患者腹痛缓解时间﹑血清淀粉酶恢复时间﹑总住院天数,总治疗费用;经不同治疗后,两组患者胰腺及胰周感染胰腺假性囊肿的发生率;对两组临床效果效率进行评价。结果〓血清淀粉酶、尿淀粉酶、血糖、血钙水平以及APACHE-Ⅱ评分第六天、第十天的恢复结果,区域灌注组优于常规组(P<0.05),血淀粉酶恢复时间7.2±1.6 d,区域灌注组优于常规组,腹痛缓解时间3.1±1.3 d,区域灌注组优于常规组(P<0.05)。接受区域灌注治疗的患者的平均住院时间明显缩短,腹膜后感染、胰腺假性囊肿、行胰肠内引流手术例数明显低于常规组,总临床效果好于常规组(P<0.05)。结论〓区域灌注在治疗重症急性胰腺炎方面有其优势,可结合其他手段作为针对坏死性胰腺炎的联合治疗方案。