腰麻-硬膜外联合麻醉对老年患者血液动力学的影响

目的 观察腰麻-硬膜外联合麻醉对老年患者血液动力学的影响.方法 选择60例65岁及以上ASA Ⅱ～Ⅲ级,择期行单侧下肢全膝关节置换术的患者,随机分成腰麻-硬膜外联合麻醉组和连续硬膜外麻醉组,每组30例.记录患者一般情况,手术时间,术中出血量,液体输入量.观察腰麻或硬膜外给药前、给药后15 min和术毕时的MAP及HR.记录感觉阻滞平面和改良Bromage运动分级.观察需要给与麻黄碱或阿托品的病例数,以及出现止血带疼痛的人数.结果 2组患者一般情况、手术时间、术中出血量、液体输入量无差异,感觉阻滞平面无明显差异,运动阻滞程度有显著差异.各个时间点的MAP及HR无显著性差异.2组给予麻黄碱和阿托品的例数无显著性差异.2组出现止血带疼痛的例数相比有显著行差异.结论 对行全膝关节置换术的老年患者实施腰麻-硬膜外联合麻醉,引起的血液动力学改变与硬膜外麻醉相比无明显差异,且患者止血带反应较轻.     

全麻复合硬膜外阻滞对血液动力学的影响

目的 观察浅全麻复合硬膜外阻滞对血液动力学的影响。方法 随机将２１例择期行腹腔镜胆囊切除手术病人分为全身麻醉组（ＧＡ组,１１例）和浅全麻复合硬膜外阻滞组（ＧＡ＋ＥＡ组,１０例）,采用Ｓｗａｎ－Ｇａｎｚ导管技术,分别监测ＧＡ组吸入０．６ＭＡＣ、１．０ＭＡＣ安氟醚与ＧＡ＋ＥＡ组吸入０．６ＭＡＣ安氟醚基础上硬膜外注入２％利多卡因７ｍｌ前后血液动力学的变化。结果 两组吸入０．６ＭＡＣ安氟醚,ＭＡＰ均显著下     

Differing incidences of relevant hypotension with combined spinal-epidural anesthesia and spinal anesthesia

In this investigation we assessed whether patients receiving spinal anesthesia (SPA) as part of combined spinal-epidural anesthesia (CSE) more often experience relevant hypotension than patients receiving SPA alone. From January 1, 1997, until August 5, 2000, electronic anesthesia records from 1596 patients having received SPA and 1023 patients having received CSE for elective surgery were collected by using a computerized anesthesia record-keeping system. Relevant hypotension was defined as a decrease of mean arterial blood pressure of more than 30% within a 10-min interval and a therapeutic action of the attending anesthesiologist within 20 min after onset. Electronic patient charts were reviewed by using logistic regression with a forward stepwise algorithm to identify independent risk factors that were associated with an increased incidence of hypotension after CSE. Univariate analysis was performed to assess differences in biometric data and relevant risk factors for hypotension between the two procedures. The incidence of relevant hypotension was more frequent with CSE than with SPA alone (10.9% versus 5.0%; P < 0.001). In the multivariate analysis, arterial hypertension (odds ratio, 1.83; 95% confidence interval, 1.21-2.78) and sensory block height >T6 (odds ratio, 2.81; 95% confidence interval, 1.88-4.22) were found to be factors associated with hypotension in the CSE group. Compared with patients receiving SPA alone, patients undergoing CSE had a significantly more frequent prevalence of arterial hypertension and higher sensory block levels (P < 0.01) despite smaller amounts of local anesthetics. In this study, patients receiving CSE had an increased risk for relevant hypotension as compared with patients with SPA alone. Part of this effect seems to be due to the procedure alone and not only because this population is at higher risk. IMPLICATIONS: This study, based on a large number of patients with a retrospective design by using on-line recorded data, suggests that spinal anesthesia as part of combined spinal-epidural anesthesia may more often lead to relevant hypotension than spinal anesthesia alone. Preexisting arterial hypertension and a sensory block height exceeding T6 are major risk factors for the development of this complication.     

Flotrac/Vigileo系统测量腰硬联合麻醉下右美托咪啶负荷剂量对血流动力参数的影响

【摘要】 目的 观察使用Flotrac/Vigileo系统监测下,右美托咪啶负荷剂量对血流动力学参数的影响。方法 60例择期在腰硬联合麻醉下行泌尿腹腔镜手术的患者,随机分为右美托咪啶组(Dex组)和对照组(Con组)。腰麻平面固定后,Dex组泵注0.5 ?滋g/kg右美托咪啶,Con组泵注等量生理盐水,泵注时间为10 min。通过Flotrac/Vigileo系统监测并记录麻醉前、麻醉平面稳定后、开始泵注药物后1 min、3 min、5 min、7 min、10 min、30 min的MAP、HR、CO、CI、CVP,根据以上参数在Vigileo监护仪上计算相应时点的外周血管阻力(SVR),并从桡动脉抽血行血气检测以了解相应时点的血乳酸值。结果 与Con组相比,Dex组患者用药1 min后SVR降低、CVP升高(P<0.05);5 min后CO及CI均下降(P<0.05);7 min后MAP下降(P<0.05);10 min后HR下降(P<0.05);Lac无明显差异。结论 右美托咪啶负荷剂量可引起血压下降伴心率、心输出量及外周血管阻力降低,CVP升高。Flotrac/Vigileo监测系统能更早反映血流动力学参数的变化。     

General versus epidural anesthesia for femoral-popliteal bypass surgery

This study examines whether epidural anesthesia is more effective than general anesthesia using an inhalation agent in controlling cardiovascular responses during femoral-popliteal bypass surgery. Nineteen patients were randomized into two groups: general anesthesia (n = 10) and epidural anesthesia (n = 9). The patients who underwent general anesthesia received sodium pentothal and succinylcholine for induction of anesthesia and 60% N2O, 40% O2, and 1% to 1.5% isoflurane for maintenance. Fifteen minutes before extubation, the patients received morphine sulfate 0.05 mg/kg intravenously (IV). The group that underwent epidural anesthesia received anesthesia to T-10 (through a catheter placed in the L4-5 interspace using 3% 2-chloroprocaine). Thirty minutes after the last dose, 0.05 mg/kg IV was administered. Hemodynamic variables were recorded at selected intervals during the operation and for 60 minutes in the recovery room. In the general anesthesia group, mean arterial pressure (MAP) and rate pressure product (RPP) significantly decreased (p less than 0.05) during the operation as compared with preoperative values. Following intubation and skin incision, 5 minutes after extubation, and after 60 minutes in the recovery room, MAP, heart rate (HR), and RPP were significantly greater (p less than 0.05) as compared with intraoperative periods. In the epidural anesthesia group, there were clinically important decreases in MAP and RPP after reaching T-10 and skin incision. The general anesthesia patients showed higher MAP, HR, and RPP 5 minutes after extubation and after 60 minutes in the recovery room. Epidural anesthesia patients showed stable hemodynamic patterns throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)     

硬膜外阻滞时罗哌卡因和布比卡因的药代动力学

目的 研究国人在硬腊外阻滞时罗哌卡因和布比卡因的药代动力学特征。方法 选择１４例手术病人、随机分为两组、硬膜外阻滞时,分别注产哌卡因２．０ｍｇ／ｋｇ或布比卡因２．０ｍｇ／ｋｇ。用气相色谱法测定血浆药物浓度。结果 罗哌卡因和布比卡因的药＝时曲线均会合二室开放模型。ｔ１／２ｋａ分别为０．２２小时和０．１４小时,Ｔ分别为０．５１和０．４７小时,Ｃａｍｘ分别１．０６ｍｇ．／ｋｇ．Ｌ＾１和１．４４ｍｇ．Ｌ＾     

腹腔镜直肠癌手术中全身麻醉复合硬膜外麻醉对患者的影响

目的:探讨腹腔镜直肠癌手术中全身麻醉复合硬膜外麻醉对患者血流动力学、呼吸功能及苏醒时间的影响。方法:选取2014年5月至2016年5月收治的80例腹腔镜直肠癌手术患者,依据随机数字表法分为全身麻醉复合硬膜外麻醉组(联合麻醉组,n=40)与单独全身麻醉组(单独麻醉组,n=40),对比分析两组患者的血流动力学、呼吸功能及苏醒时间。结果:术中2h、术后联合麻醉组患者的心率、动脉压、气道压、呼吸末二氧化碳分压均显著低于单独麻醉组(P0.05),苏醒时间、意识恢复时间、回答问题切题时间、术后拔管时间均显著短于单独麻醉组(P0.05)。结论:腹腔镜直肠癌手术中全身麻醉复合硬膜外麻醉患者的血流动力学、呼吸功能均较稳定,苏醒时间较短。     

Sensorimotor anesthesia and hypotension after subarachnoid block: combined spinal-epidural versus single-shot spinal technique

The extent of the intrathecal compartment depends on the balance between cerebrospinal fluid and subatmospheric epidural pressure. Epidural insertion disrupts this relationship, and the full impact of loss-of-resistance on the qualities of subarachnoid block is unknown. In this study we sought to determine if subarachnoid block, induced by combined spinal-epidural (CSE) using loss-of-resistance to air could render higher sensory anesthesia than single-shot spinal (SSS) when an identical mass of intrathecal anesthetic was injected. Sixty patients, scheduled for minor gynecological procedures, were randomly allocated into three groups all receiving 10 mg of 0.5% hyperbaric bupivacaine. In the SSS group, intrathecal administration was through a 27-gauge Whitacre spinal needle inserted at the L3-4 level. For the CSE group, the epidural space was identified with an 18-gauge Tuohy needle using loss-of-resistance to 4 mL of air. After intrathecal administration, a 20-gauge catheter was left in the epidural space. No further drug or saline was administered through the catheter. The procedure was repeated in group CSE ((no-catheter)) except without insertion of a catheter. Sensorimotor anesthesia was assessed at regular 2.5-min intervals until T10 was reached. In all aspects, there was no difference between CSE and CSE ((no-catheter)). Peak sensory level in SSS was lower than CSE and CSE ((no-catheter)) (median T5 [max T3-min T6] versus (T3 [T1-4] and (T3 [T2-5]) (P < 0.01). During the first 10 min postblock, dermatomal thoracic block was the lowest in SSS (P < 0.05). Time for regression of sensory level to T10 was also shortest in SSS. Hypotension, ephedrine use and period of motor recovery were more pronounced in CSE and CSE ((no-catheter)). We conclude that subarachnoid block induced by CSE produces greater sensorimotor anesthesia and prolonged recovery compared with SSS. There is also a more frequent incidence of hypotension and vasoconstrictor use despite using identical doses and baricity of local anesthetic. IMPLICATIONS: This study confirms that induction of subarachnoid block by a combined-spinal epidural technique produces a greater sensorimotor anesthesia and results in prolonged recovery when compared with a single-shot spinal technique. There is a more frequent incidence of hypotension and vasoconstrictor administration despite identical doses of intrathecally administered local anesthetic.     

Combined low-dose spinal-epidural anesthesia versus single-shot spinal anesthesia for elective cesarean delivery

Combined spinal-epidural anesthesia balancing low-dose intrathecal bupivacaine/fentanyl and low-dose epidural bupivacaine may be more useful than single-shot spinal anesthesia for cesarean delivery in reducing incidences of adverse effects such as hypotension and nausea and in shortening motor recovery. Combined spinal-epidural anesthesia (n=50) or spinal anesthesia (n=50) was randomly performed in 100 parturients. Intrathecal bupivacaine 6 mg added by fentanyl 20 mug followed after 5 min by 10 mL of 0.25% epidural bupivacaine were used for combined spinal-epidural and intrathecal bupivacaine 9 mg with fentanyl 20 mug for spinal anesthesia. The initial sensory block level was higher in the spinal group (P<0.001), although the maximum levels were the same (T3). Complete surgical anesthesia was achieved and no patient complained of intraoperative pain in either group. Patients in the spinal group had denser motor block in the extremities and a higher incidence of hypotension (P<0.05) and nausea and vomiting (P<0.05). Motor recovery was faster in the combined spinal-epidural group (P<0.001). We concluded that combined spinal-epidural anesthesia using low-dose local anesthetic-opioid spinal anesthesia and routine epidural supplementation before surgery had some potential advantages over single-shot spinal anesthesia in the lower incidences of adverse effects and quicker recovery.     

A randomized trial comparing low-dose combined spinal-epidural anesthesia and conventional epidural anesthesia for cesarean section in severe preeclampsia

BACKGROUND AND OBJECTIVES: A prospective, randomized study was designed to compare the maternal and neonatal effects of conventional epidural anesthesia and combined spinal epidural anesthesia (CSE) for Cesarean section in severe preeclamptic patients. Additionally, two strategies in the prophylactic management of hypotension in severe preeclamptic patients were evaluated: fluid preloading or prophylactic ephedrine. METHODS: Thirty nonlaboring women with severe preeclampsia (PET), scheduled for an elective Cesarean section, were randomised into three groups: epidural anesthesia with prophylactic fluid loading (EA-F), combined spinal epidural anesthesia with prophylactic fluid loading (CSE-F), or combined spinal epidural anesthesia with prophylactic ephedrine (CSE-V). Hemodynamic data were recorded prior and after induction of regional anesthesia at five-minute intervals. The total amount of intravenous administered fluid and the total dose of vasopressors were recorded. RESULTS: Hemodynamic data were similar between the three groups. The incidence and duration of hypotension was similar in all three groups. Significantly more ephedrine was used in the CSE-V group as compared to the CSE-F group. More lactated Ringer's solution was used in the CSE-F group as compared to the CSE-V group. There were no hypertensive episodes and none of the patients developed pulmonary edema. The time period from induction until the start of surgery and the duration of surgery were significantly shorter in both CSE-groups. Neonatal outcome was comparable between the three groups. CONCLUSION: Our results confirm that combined spinal and epidural anesthesia (CSE) is a safe alternative to conventional epidural anesthesia in severe preeclamptic women and that the prophylactic use of ephedrine is effective and safe to prevent and treat spinal hypotension after combined spinal and epidural anesthesia for Cesarean section in severe preeclamptic women.     

Vigilance of hemodynamic changes immediately after transferring patients is crucial

Purpose

A decrease in blood pressure is sometimes observed when a postsurgical patient is transferred to another bed after recovering from anesthesia. However, the mechanism behind this hypotension has not been completely elucidated. The purpose of this study was to investigate and compare changes in hemodynamic properties for possible causes of hypotension before and after transfer to another bed of postsurgical patients receiving general anesthesia, combined epidural and general anesthesia, or combined spinal and general anesthesia.

Methods

We studied 69 patients undergoing elective surgery who were randomized to receive anesthesia by one of the three methods. After surgery, the tracheal tube was removed, and each patient was transferred to another bed. Hemodynamic data recorded immediately before and after transfer of the patient to another bed were compared.

Results

After transfer of patients receiving general anesthesia or combined epidural and general anesthesia, systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and cardiac output (CO) decreased; heart rate (HR) and systemic vascular resistance (SVR) did not change. However, after transfer of patients receiving combined spinal and general anesthesia, SAP, DAP, HR, and CO decreased, but SVR did not change.

Conclusion

The decrease in blood pressure observed after transfer of a postsurgical patient to another bed after general, combined epidural and general, and combined spinal and general anesthesia was associated with a decrease in CO and no change in SVR, but HR decreased after combined spinal and general anesthesia, whereas it was unchanged after general and combined epidural and general anesthesia. The decrease in blood pressure is assumed to be caused by a decrease in venous return, and several reflexes might participate in this decrease of blood pressure, especially after combined spinal and general anesthesia.     

上腹部手术中胸段硬膜外麻醉联合全身麻醉对血流动力学的影响

目的 观察胸段硬膜外麻醉联合全身麻醉(TEA+GA)与全凭静脉麻醉(TIVA)这两种麻醉方法在上腹部手术时血流动力学参数的改变.方法 自2007年12月至2008年5月选择44例拟行择期上腹部手术的美国麻醉医师协会(ASA)Ⅱ～Ⅲ级患者,麻醉诱导前行胸段硬膜外穿刺置管.麻醉诱导及气管内插管完成后,持续静脉输注丙泊酚和雷米芬太尼维持静脉麻醉.然后患者被随机双盲分入TEA+GA组(n=22)或TIVA组(n=22).TEA+GA组患者在单次硬膜外腔注入0.25%布比卡因0.2 ml/kg后继以0.2 ml·kg-1·h-1的剂量持续输注;而TIVA组则单次硬膜外腔注入生理盐水后继之持续输注之,其容积和速率与上组相同.监测指标为:心电图、动脉收缩压(SAP)、舒张压(DAP)、平均动脉压(MAP)、心率(HR)、中心静脉压、心指数(CI)、全身血管阻力(SVR)、脉搏氧饱和度和呼气末CO2水平,间断进行血气分析.两组的观测时间均为90 min.结果 在硬膜外腔应用布比卡因或生理盐水后的观察时点,TEA+GA组SAP、DAP、MAP、HR和SVR呈显著性降低;与TIVA组相比,TEA+GA组SAP、DAP、MAP和SVR的降低均具有统计学意义(P≤0.05).但TEA+GA组CI、SV改变不大,与TIVA组相比差异无统计学意义.结论 TEA+GA麻醉中尽管血压呈一定程度下降,但可能与体循环阻力降低有关,而其心功能并未受到明显抑制.提示TEA+GA麻醉方法具有较好的心血管系统稳定性.     

Frequency of hypotension and bradycardia during general anesthesia, epidural anesthesia, or integrated epidural-general anesthesia for total hip replacement

STUDY OBJECTIVE: To evaluate the frequency of hypotension and bradycardia during integrated epidural-general anesthesia as compared with general anesthesia or epidural anesthesia alone. DESIGN: Prospective, randomized, open, multicenter study. SETTING: Inpatient anesthesia at 7 University or Hospital Departments of anesthesia. PATIENTS: 210 ASA physical status I, II, and III patients undergoing elective total hip replacement. INTERVENTIONS: Using a balanced randomization method, each hospital enrolled 30 consecutive patients who received integrated epidural-general anesthesia, epidural anesthesia, or general anesthesia. MEASUREMENTS AND MAIN RESULTS: Occurrence of clinically relevant hypotension (systolic arterial blood pressure (BP) decrease >30% from baseline), or bradycardia (heart rate (HR) <45 bpm) requiring pharmacologic treatment were recorded, as well as routine cardiovascular parameters. Clinically relevant hypotension during induction of nerve block was reported in 13 patients receiving epidural block (18%) and 16 patients receiving epidural-general anesthesia (22%) (p = 0.67). Subsequently, 22 of the remaining 54 patients in the epidural-general anesthesia group (41%) developed hypotension after the induction of general anesthesia, as compared with 16 patients of the general anesthesia group (23%) (p = 0.049). No differences in HR or in frequency of bradycardia were observed in the three groups. CONCLUSIONS: The induction of general anesthesia in patients with an epidural block up to T10 increased the odds of developing clinically relevant hypotension as compared with those patients who received no epidural block, and was associated with a twofold increase of the odds of hypotension as compared with the use of epidural anesthesia alone.     

The use of central regional anesthesia techniques in Sweden: results of a nation-wide survey

Background: Epidural and subarachnoid anesthesia are well established central regional techniques for surgical anesthesia. TWO additional techniques, combined spinal epidural (CSE) block and continuous spinal anesthesia (CSA), have recently become popular. However, data on nation-wide use of central regional blocks are not available.
Method: With the aims to survey the use of central regional techniques, to evaluate the risk of complications to central regional blocks and to document the use of continuous epidural techniques for postoperative pain management in Sweden during 1993, a questionnaire was mailed to all 105 Swedish anesthesiology departments.
Results: Questionnaires were returned by 62 departments, representing all categories of Swedish hospitals. Central regional blocks were used for surgical anesthesia in 2040% of reported surgical procedures. Subarachnoid anesthesia was the main technique for orthopedic surgery on the lower limb, elective cesarean section and transurethral resection of the prostate. Epidural block was used for orthopedic and vascular surgery. CSE block was used by 42 departments and CSA by 21 departments. Postoperative epidural analgesia was used by 59 departments, most commonly with continuous infusion of local anesthestics and/or epidural bolusdoses of morphine. Nineteen neurological sequelae were reported after epidural (n=7) and subarachnoid (n=12) blocks. Routines for registration of complications varied greatly.
Conclusions: Subarachnoid block was preferred for shorter surgical procedures (<60 min), whereas epidural and CSE blocks were chosen when severe postoperative pain could be anticipated, as continuous epidural analgesia was well established for postoperative pain management. Improved routines for registration of complications to central regional blocks are needed.     

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

AIM: The aim of our study was to prove that by using sequential combined spinal-epidural (CSE) anesthesia it is possible to overcome the limits connected to the use of spinal anesthesia (SA) alone for elective cesarean section. METHODS: We examined 100 women submitted to cesarean section; SA was administered to 50 patients and sequential CSE technique to the other 50. In every woman before execution of the anesthesia we infused 500 mL of a plasma expander and a previous administration of 5 mg of ephedrine. The CSE was executed at the L1-L2 intervertebral space, administering in spinal anesthesia 5 mg of levobupivacaine with 5 _g of sufentanil, and in peridural anesthesia 10-12 mL of levobupivacaine 0.25% according to the patient's height. The peridural catheter for postoperative analgesia was then positioned. In the group of women submitted only to SA, 7.5-8 mg of levobupivacaine was injected, according to the patient's height, in the L1-L2 intervertebral space, with 5 _g of sufentanil. We considered the following adverse effects: hypotension; bradycardia; vomiting; intraoperative discomfort and motor block. RESULTS: The results obtained showed that, with a P < or = 0.05, the incidence of motor block (P < 0.001), discomfort (P < 0.001) and hypotension (P = 0.021) in the SA group is greater than in the CSE group. The difference in the incidence of vomiting (P = 0.147) and bradycardia (P = 0.067) between the 2 groups is not statistically significant. CONCLUSIONS: In our opinion sequential CSE can be considered an important step forward in the regional anesthesia used for elective cesarean section.     

Cardiopulmonary complications after major surgery: a role for epidural analgesia?

Improvement in postoperative pulmonary mechanics with epidural analgesia has been described. Data on the hemodynamic effects of this technique are absent from the surgical literature. To provide such data we have evaluated two groups of patients undergoing aortic reconstruction: group I (n = 25), general anesthesia and group II (n = 6), general anesthesia with adjunctive epidural analgesia. The groups were comparable preoperatively as judged by the incidence of cardiac history, preoperative ejection fraction, and measured hemodynamic parameters. Postoperatively there were no significant differences in the pressure-related parameters; however, rate-related factors including heart rate and double product were significantly decreased in group II with no reduction in cardiac index. Postoperative increases in total body oxygen consumption were also markedly attenuated by epidural analgesia. Epidural analgesia reduces the hemodynamic demands on the heart after major surgery and is a useful adjunct, especially in patients with coronary artery disease.     

Halothane anesthesia suppresses reflex tachycardia caused by calcitonin gene-related peptide in dogs

Calcitonin gene-related peptide (CGRP) is known to produce vasodilation, hypotension, and tachycardia. To investigate the interaction between CGRP and anesthetics, the hemodynamic response to infusions of CGRP was studied in dogs anesthetized with halothane or pentobarbital. In halothane-anesthetized dogs given 0.4 μg·kg⁻¹ of CGRP, mean arterial pressure (MAP) did not change significantly. However, there was a significant reduction in systemic vascular resistance (SVR) associated with significant increases in cardiac index (CI) and stroke volume index (SVI). Higher doses (4 and 40 μg·kg⁻¹) of CGRP produced dose-dependent decreases in MAP accompanied by a reduction in SVR. Further, both CI and SVI significantly increased at 4 μg·kg⁻¹ CGRP but remained unchanged at the 40 μg·kg⁻¹ infusion rate. Heart rate (HR) was not increased at all doses but was decreased at 40 μg·kg⁻¹. In pentobarbital-anesthetized dogs, CGRP at doses of 4 μg·kg⁻¹ produced a qualitatively similar cardiovascular responses as that observed in halothane-anesthetized dogs, but with one exception: HR was significantly increased. The results show that the hemodynamic profiles induced by CGRP during halothane or pentobarbital anesthesia are a decrease in MAP accompanied by a reduction in SVR and no consistent alterations in CI. However, CGRP effects on HR showed in a different way. The results also show that HR response differs depending on the anesthetics used: HR increases during pentobarbital anesthesia, while it does not increase during halothane anesthesia. This study was presented in part at the 39th annual meeting of the Japan Society of Anesthesiology, Fukuoka, April 1992, and at the annual meeting of the American Society of Anesthesiologists, New Orleans, October 1992     

A randomized trial of crystalloid versus colloid solution for prevention of hypotension during spinal or low-dose combined spinal-epidural anesthesia for elective cesarean delivery

BACKGROUND: Spinal anesthesia for cesarean delivery is commonly associated with hypotension and nausea and vomiting, and preload with crystalloid or colloid solution is widely recommended. Low-dose spinal via the combined spinal-epidural technique appears to cause less hypotension and nausea and vomiting. The aim of this study was to investigate whether the combined use of colloid preload and combined spinal-epidural technique might further reduce the rates of these symptoms. METHODS: Women undergoing elective cesarean delivery were randomly allocated to one of four groups (50 in each) to receive crystalloid preload before spinal anesthesia, colloid preload before spinal anesthesia, crystalloid preload before combined spinal-epidural anesthesia, and colloid preload before combined spinal-epidural anesthesia. The incidences of hypotension and nausea and vomiting were compared. Spinal anesthesia was performed with 0.5% hyperbaric bupivacaine 9 mg and fentanyl 20 microg, and combined spinal-epidural anesthesia with 0.5% hyperbaric bupivacaine 6 mg + fentanyl 20 microg followed by epidural injection of 0.25% bupivacaine 10 mL. RESULTS: The frequencies of hypotension were 44%, 18%, 24%, and 20% in crystalloid preload-spinal anesthesia, colloid preload-spinal anesthesia, crystalloid preload-combined spinal epidural anesthesia, and colloid preload-combined spinal epidural anesthesia groups, respectively. The frequencies of nausea and vomiting were 20%, 2%, 8%, and 4% in respective groups. CONCLUSION: Colloid preload and low-dose spinal anesthesia alone or in combination lowered the incidences of hypotension and nausea. However, the combination of two methods failed to demonstrate further decreases in the incidence of the symptoms compared to the colloid-spinal anesthesia or crystalloid-combined spinal-epidural anesthesia groups.     

七氟醚麻醉中阻塞性黄疸患者的血流动力学变化

目的 探讨阻塞性黄疸患者在七氟醚吸入麻醉过程中血流动力学的变化.方法 择期手术患者80例,ASA Ⅰ或Ⅱ级,按照血清总胆红素(sTBL)水平分为观察组(A组,sTBL≥17.1μmol/L)和对照组(B组,sTBL<17.1 μmol/L),每组40例.分别在麻醉诱导前、呼出气七氟醚浓度在1.0 MAC和1.5 MAC并维持10 min时记录血流动力学指标.结果 麻醉诱导前A组MAP、HR、全身血管阻力(SVR)、心脏指数(CI)、肺毛细血管楔压(PCWP)明显低于B组(P<0.05或P<0.01).1.0 MAC时A组MAP、平均肺动脉压(MPAP)、CI、每搏指数(SI)的下降百分率均明显大于B组(P<0.05或P<0.01).1.5MAC时A组患者MPAP、MAP、CI的下降百分率明显大于B组(P<0.05或P<0.01).结论 与非阻塞性黄疸患者比较,阻塞性黄疸患者血流动力学随七氟醚呼出气浓度增加而波动增大.     

Epidural clonidine suppresses the baroreceptor-sympathetic response depending on isoflurane concentrations in cats

Epidural administration of clonidine induces hypotension and bradycardia secondary to decreased sympathetic nerve activity. In this study, we sought to elucidate the change in baroreflex response caused by epidural clonidine. Thirty-six cats were allocated to six groups (n = 6 each) and were given either thoracic epidural clonidine 4 micro g/kg or lidocaine 2 mg/kg during 0.5, 1.0, or 1.5 minimum alveolar anesthetic concentration (MAC) isoflurane anesthesia. Heart rate (HR), mean arterial blood pressure (MAP), and cardiac sympathetic nerve activity (CSNA) were measured. Depressor and pressor responses were induced by IV nitroprusside 10 micro g/kg and phenylephrine 10 micro g/kg, respectively. Baroreflex was evaluated by the change in both CSNA and HR relative to the peak change in MAP (deltaCSNA/deltaMAP and deltaHR/deltaMAP, respectively). These measurements were performed before and 30 min after epidural drug administration. Epidural clonidine and lidocaine decreased HR, MAP, and CSNA by similar extents. deltaCSNA/deltaMAP and deltaHR/deltaMAP for depressor response were suppressed with epidural lidocaine and clonidine in all groups but the clonidine 0.5 MAC isoflurane group (0.197 +/- 0.053 to 0.063 +/- 0.014 and 0.717 +/- 0.156 to 0.177 +/- 0.038, respectively, by epidural lidocaine [P < 0.05] but 0.221 +/- 0.028 to 0.164 +/- 0.041 and 0.721 +/- 0.177 to 0.945 +/- 0.239, respectively, by epidural clonidine during 0.5 MAC isoflurane). Those for pressor response were suppressed in all groups. We conclude that thoracic epidural clonidine suppresses baroreflex gain during isoflurane anesthesia >1.0 MAC but may offer certain advantages compared with epidural lidocaine during 0.5 MAC isoflurane by virtue of preserving baroreflex sensitivity when inadvertent hypotension occurs.