Prophylactic effects of systemic oral ephedrine in spinal anesthesia-induced hypotension during transurethral prostatectomy

OBJECTIVE: We investigated the prophylactic effects of systemic oral ephedrine in spinal anesthesia-induced hypotension during transurethral prostatectomy. MATERIAL AND METHODS: Sixty American Society of Anesthesiologists Grade II and III patients scheduled for spinal anesthesia were randomized into one of two groups. Patients in Group I (n = 30) received oral ephedrine 50 mg in addition to premedication whilst those in Group II (n = 30) received only premedication 30 min before spinal anesthesia. Pre-infusion values were measured in order to obtain baseline readings after oral ephedrine administration in Group I and after premedication in Group II. Systolic arterial pressure (SAP) and heart rate (HR) were recorded before and after infusion, during and 5 min after spinal anesthesia and intraoperatively. Hypotension was defined as SAP <100 mmHg and <20% of baseline value. Hypotension was treated with 3 mg ephedrine and bradycardia was corrected with atropine 0.5 mg, given as an i.v. bolus. RESULTS: SAP values were significantly lower in Group II during the spinal anesthesia, post-spinal and intraoperative periods (p < 0.0001). Fifteen patients received ephedrine in Group II and seven in Group I. Supplemental ephedrine was used at doses of 3.42 +/- 0.97 mg in Group I and 8.86 +/- 1.24 mg in Group II. The incidence of hypotension was halved in Group I compared to Group II (23.33% vs 50%, p = 0.003). Six patients received atropine in Group II because of severe bradycardia. Mean HR values were lower in Group II than Group I during the spinal anesthesia, post-spinal and intraoperative periods. CONCLUSIONS: We conclude that a prophylactic oral dose of ephedrine 50 mg is effective for minimizing and managing spinal anesthesia-induced hypotension during transurethral prostatectomy.     

Role of the atrial natriuretic factor in obstetric spinal hypotension

BACKGROUND: In recent years, the concept of prophylactic volume expansion to prevent hypotension caused by spinal anesthesia has been challenged. Investigators have reevaluated the concept of prehydration in the obstetric patient and the physiologic mechanisms involved. This article addresses whether the hypotensive effects attributed to the atrial natriuretic factor are the reason for the apparent failure of prehydration. METHODS: Atrial natriuretic factor was measured before (baseline) and 10 min after spinal anesthetic drug injection (control) in 48 healthy pregnant patients scheduled for elective cesarean section. Sixteen patients received hydration with 15 ml/kg crystalloid immediately before spinal anesthesia, 16 patients received the same volume starting with the spinal anesthetic injection, and the remaining 16 patients received no prehydration (control). Blood pressure, heart rate, ephedrine requirements, infused fluids, and urine output were measured. RESULTS: Atrial natriuretic factor concentrations increased significantly in prehydrated patients but not in the control group. There was a significant correlation in the change in atrial natriuretic factor concentrations and urine output but no correlation in the control atrial natriuretic factor concentrations and blood pressure or ephedrine requirements. Ephedrine requirements and blood pressure did not differ significantly among study groups. CONCLUSIONS: Atrial natriuretic factor is a potent endogenous diuretic in the pregnant patient but does not appear to be involved in short-term cardiovascular homeostasis after spinal anesthesia. Prehydration appears to be an ineffective measure to prevent post spinal hypotension in the obstetric patient [corrected].     

Role of the Atrial Natriuretic Factor in Obstetric Spinal Hypotension

Background: In recent years, the concept of prophylactic volume expansion to prevent hypotension caused by spinal anesthesia has been challenged. Investigators have reevaluated the concept of prehydration in the obstetric patient and the physiologic mechanisms involved. This article addresses whether the hypotensive effects attributed to the atrial natriuretic factor are the reason for the apparent failure of prehydration.

Methods: Atrial natriuretic factor was measured before (baseline) and 10 min after spinal anesthetic drug injection (control) in 48 healthy pregnant patients scheduled for elective cesarean section. Sixteen patients received hydration with 15 ml/kg crystalloid immediately before spinal anesthesia, 16 patients received the same volume starting with the spinal anesthetic injection, and the remaining 16 patients received no prehydration (control). Blood pressure, heart rate, ephedrine requirements, infused fluids, and urine output were measured.

Results: Atrial natriuretic factor concentrations increased significantly in prehydrated patients but not in the control group. There was a significant correlation in the change in atrial natriuretic factor concentrations and urine output but no correlation in the control atrial natriuretic factor concentrations and blood pressure or ephedrine requirements. Ephedrine requirements and blood pressure did not differ significantly among study groups.     

Decreased heart rate and blood pressure in a recent cardiac transplant patient after spinal anesthesia

PURPOSE: To describe the cardiovascular effects of neuraxial blockade in a heart transplant patient. CLINICAL FEATURES: A 69-yr-old 70-kg male underwent orthotopic heart transplant (bicaval anastomosis technique) for ischemic cardiomyopathy. Five months after transplantation, the patient underwent a transurethral bladder tumour resection under spinal anesthesia. Two millilitres of bupivacaine 0.75% (15 mg) were injected intrathecally at L(3-4) and the patient remained seated for approximately 20 sec prior to assuming the lithotomy position. Subsequently, both blood pressure (BP) and heart rate (HR) diminished gradually (BP and HR immediately pre-spinal: 113 mmHg (mean arterial pressure) and 92 beats x min(-1), respectively; nadir BP and HR: 94 mmHg (16.8% decrease) 30 min postspinal and 73 beats x min(-1) (20.7% decrease) 40 min postspinal, respectively). HR and mean BP were highly correlated (r = 0.9410, P < 0.0001, R(2) = 0.8854). The dermatome level of neuraxial anesthesia, determined by sensitivity to pin prick, was T(8) (five minutes) and T(6) (ten minutes) postinjection of spinal anesthetic. Control patients (n = 10) undergoing elective urological procedures with identical anesthesia management demonstrated very similar cardiovascular responses. CONCLUSIONS: Although cardiac transplant patients may tolerate neuraxial anesthesia admirably, a fall in HR may ensue which theoretically could have important physiological consequences. It is argued that the change in HR in the transplanted patient was mediated by mechanisms intrinsic to the transplanted heart and/or by reduced catecholamine secretion from the adrenal medulla. It is emphasized that HR changes observed in cardiac transplant patients do not necessarily imply reinnervation of the transplanted organ.     

Low-dose bupivacaine-fentanyl spinal anesthesia for cesarean delivery

BACKGROUND AND OBJECTIVES: The hypotension following spinal anesthesia remains commonplace in cesarean delivery. Intrathecal opioids are synergistic with local anesthetics and intensify sensory block without increasing sympathetic block. The combination makes it possible to achieve spinal anesthesia with otherwise inadequate doses of local anesthetic. We hypothesized that this phenomenon could be used to provide spinal anesthesia for cesarean delivery while incurring less frequent hypotension. METHODS: Thirty-two women scheduled for cesarean delivery were divided into 2 groups of patients who received a spinal injection of either 10 mg of isobaric (plain) bupivacaine 0.5% or 5 mg of isobaric bupivacaine with 25 microg fentanyl added. Each measurement of a systolic blood pressure less than 95 mm Hg or a decrease in systolic pressure of greater than 25% from baseline was considered as hypotension and treated with a bolus of 5 to 10 mg of intravenous ephedrine. RESULTS: Spinal block provided surgical anesthesia in all patients. Peak sensory level was higher (T3 v T4. 5) and motor block more intense in the plain bupivacaine group. The plain bupivacaine patients were more likely to require treatment for hypotension (94% v 31%) and had more persistent hypotension (4.8 v 0.6 hypotensive measurements per patient) than patients in the minidose bupivacaine-fentanyl group. Mean ephedrine requirements were 23.8 mg and 2.8 mg, respectively, for the 2 groups. Patients in the plain bupivacaine group also complained of nausea more frequently than patients in the minidose bupivacaine-fentanyl group (69% v 31%). CONCLUSIONS: Bupivacaine 5 mg + fentanyl 25 microg provided spinal anesthesia for cesarean delivery with less hypotension, vasopressor requirements, and nausea than spinal anesthesia with 10 mg bupivacaine.     

Prevention of hypotension by a single 5-mg dose of ephedrine during small-dose spinal anesthesia in prehydrated cesarean delivery patients

To evaluate the effectiveness of prophylactic ephedrine for the prevention of hypotension associated with spinal anesthesia, 50 parturients undergoing cesarean delivery received either ephedrine 5 mg or saline IV in a double-blinded fashion immediately after the induction of spinal anesthesia. Spinal anesthesia was performed with hyperbaric bupivacaine 6.6 mg combined with sufentanil 3.3 microg as part of a combined spinal-epidural technique. All patients received 1000 mL of lactated Ringer's solution and 500 mL of hydroxyethylstarch 6% before the spinal injection. Additional ephedrine boluses (5 mg) were administered IV when the systolic blood pressure or heart rate decreased by more than 30% from baseline values, when systolic blood pressure became <100 mm Hg, or when patients complained of nausea or feeling faint. The height of the block was equal in the groups; however, more patients in the placebo group were found to develop hypotension (58% vs 25%, P < 0. 05). Only 2 (8%) patients in the ephedrine group developed hypotension with systolic blood pressure values <90 mm Hg, whereas 10 patients (42%) in the saline group experienced hypotension of this severity (P < 0.05). In addition, there was a higher incidence of nausea in the placebo-treated patients. The total amount of ephedrine administered did not differ between groups. These findings suggest that the incidence and severity of hypotension are significantly reduced by the IV administration of a prophylactic dose of 5 mg ephedrine in patients receiving small-dose spinal anesthesia for cesarean delivery. IMPLICATIONS: Ephedrine is the drug most often used to correct hypotension during spinal anesthesia for cesarean delivery in healthy patients. A single IV dose of 5 mg decreases the occurrence and limits the severity of hypotension in prehydrated subjects receiving a small-dose spinal local anesthetic-opioid combination.     

Clinical effects of L-threo-3,4-dihydroxyphenylserine on orthostatic hypotension in hemodialysis patients

Orthostatic hypotension is one of the major factors interfering with everyday activities in hemodialysis patients, but there has been no effective agent for treating it. In order to clarify the clinical effects of L-threo-3,4-dihydroxyphenylserine (L-DOPS) on orthostatic hypotension of hemodialysis patients, we conducted a randomized, double-blind comparative trial. 149 regular hemodialysis patients with orthostatic hypotension were randomly allocated to three groups and L-DOPS at doses of 400 mg, 200 mg or placebo was orally administrated to each group 30 min before starting every hemodialysis for 4 weeks. Changes of blood pressure (BP) in orthostatic hypotension immediately after completion of hemodialysis and symptoms related to orthostatic hypotension were compared between the three groups. In the 400-mg group, systolic and diastolic BP after standing increased significantly and the drop of mean BP after standing was also reduced compared with pretreatment levels. No such changes were observed in the placebo group. Fatiguability, malaise/weakness, dizziness and light-headed feeling, the interdialytic symptoms commonly observed in hemodialysis patients who developed orthostatic hypotension, were improved to a significant extent in the L-DOPS group compared with the placebo group. In particular, the improvement was more remarkable for the L-DOPS 400-mg group than the placebo group in patients with diabetic nephropathy, lower systolic BP after standing, and the long duration type of orthostatic hypotension. The incidence of adverse events was comparable between the three groups, and all recovered after discontinuation of L-DOPS or concomitantly administered drugs, or without any treatment. These findings indicate that L-DOPS taken before hemodialysis prevents orthostatic hypotension in patients undergoing hemodialysis, and is also effective for the interdialytic symptoms related to orthostatic hypotension.     

Ephedrine requirements are reduced during spinal anaesthesia for caesarean section in preeclampsia

BACKGROUND: Despite controversy over the haemodynamically safest blockade for caesarean section in women with severe preeclampsia, an increasing number of anaesthetists now opt for spinal anaesthesia. In a previous study we found that spinal compared to epidural anaesthesia offered an equally safe but more effective option for these patients. The current study was designed to compare the hypotension induced by spinal anaesthesia, as measured by ephedrine requirement, between 20 normotensive and 20 severely preeclamptic but haemodynamically stabilised women. METHOD: Standardised spinal anaesthesia was instituted and ephedrine was given in boluses of 6 mg if the systolic pressure fell >20% from the baseline, or if the patient exhibited symptoms of hypotension. RESULTS: The mean ephedrine requirement of the normotensive group (27.9+/-11.6 mg) was significantly greater (P<0.01) than that of the preeclamptic group (16.4+/-15.0 mg). CONCLUSION: This suggests that the hypotension induced by spinal anaesthesia in women with severe but haemodynamically stabilised preeclampsia, is less than that of normotensive patients.     

麻黄碱及甲氧明用于剖宫产腰麻低血压的防治

目的比较麻黄碱与甲氧明用于剖宫产腰麻低血压的防治效果。方法 90例择期腰麻剖宫产产妇随机分为三组,当腰麻后血压低于80%基础值时分别静注麻黄碱12 mg(E组)、甲氧明2 mg(M组)或麻黄碱6 mg+甲氧明1 mg(EM组)。观察各组产妇腰麻后血流动力学变化,测定胎儿取出后脐动脉血气值。结果三组SBP差异无明显统计学意义。HR<60次/分的产妇M组11例(23.3%),显著多于E组的0例和EM组的1例(3.3%)(P<0.05);HR>100次/分的产妇E组11例(36.7%),显著多于M组(0例)及EM组(0例)(P<0.05)。胎儿娩出后1、5 min的Apgar评分三组间差异无统计学意义。脐动脉pH值E组显著低于M组及EM组(P<0.05);脐动脉BE值E组显著高于M组及EM组(P<0.05)。结论麻黄碱与甲氧明单独或联合均可有效防治剖宫产腰麻后低血压发生,但麻黄碱与甲氧明联合使血流动力学更稳定,甲氧明单用与甲氧明与麻黄碱联合应用使胎儿酸碱平衡更稳定。     

Is ephedrine infusion more effective at preventing hypotension than traditional prehydration during spinal anaesthesia for caesarean section in African parturients?

BACKGROUND: Hypotension following spinal anaesthesia for caesarean section may result in maternal nausea and vomiting and decreased uteroplacental blood flow with possible fetal acidaemia. Numerous methods have been tried to minimise hypotension. In developing countries where resources are limited, this study aimed to compare a standard infusion of ephedrine with traditional prehydration to prevent spinal hypotension. METHOD: Sixty patients for elective caesarean section were randomly allocated to group 1: 1 L 0.9% saline before spinal block, and group 2: infusion of ephedrine 30 mg in 1 L of 0.9% saline after spinal block, titrated to maternal systolic pressure. Spinal anaesthesia was achieved with 2.5 mL of 0.5% heavy bupivacaine in the L3/L4 interspace. RESULTS: Systolic pressure decreased 5 min after spinal block. Group 2 had higher mean values of systolic pressure throughout most of the study period than group 1 (P < 0.05). Hypotension occurred in 70% of patients in group 1 and 40% of patients in group 2 (P = 0.037). Severe hypotension occurred in 40% of group 1 and 13.3% of group 2 (P = 0.039). Nausea was the most common side effect of hypotension, occurring in 39.4% of all hypotensive patients. Other complications, including hypertension, tachycardia and bradycardia were similar in the two groups. Neonatal outcome was similar in the two groups and median Apgar scores at one and five minutes were 8. CONCLUSION: Prophylactic ephedrine given by standard infusion set was more effective than crystalloid prehydration in the prevention of hypotension during spinal anaesthesia for elective caesarean section.     

Hemodynamic effects of simultaneous administration of intravenous ephedrine and spinal anesthesia for cesarean delivery

STUDY OBJECTIVE: To evaluate the hemodynamic effects of an intravenous (IV) ephedrine bolus given simultaneously with spinal anesthesia for cesarean delivery. DESIGN: Randomized, prospective, double-blind study. SETTING: Tertiary-care academic medical center. PATIENTS: 40 ASA physical status I and II nonlaboring women undergoing elective cesarean delivery of term, uncomplicated, singleton pregnancies. INTERVENTIONS: After a 10 mL/kg IV lactated Ringers bolus given over 15 minutes, patients simultaneously received an IV dose of 2 mL (10 mg) ephedrine or 2 mL saline, and an intrathecal dose of 12 mg (1.6 mL 0.75%) bupivacaine with 10 microg of fentanyl. Hypotension, defined as a 20% decrease in mean arterial pressure (MAP), was treated with 10-mg IV doses of ephedrine. MEASUREMENTS: Hemodynamic (heart rate and MAP) and non-invasive thoracic impedance (cardiac index, stroke index, and systemic vascular resistance index) measurements at baseline and at 1-minute intervals until the time of delivery. Total fluid, supplemental ephedrine, and Apgar scores were recorded. Data were evaluated using analysis of variance (ANOVA), ANOVA for repeated measures, and Mann-Whitney U-tests where appropriate, with p < 0.05 considered significant. MAIN RESULTS: Significant changes from baseline in MAP, systemic vascular resistance index, heart rate, and cardiac index were observed in both groups after spinal anesthesia. However, there were no differences between the ephedrine and saline groups in the incidence and severity of change from the baseline. The overall incidence of hypotension was 70% in both groups. No difference in total fluid or supplemental ephedrine use was observed. CONCLUSIONS: 10 mg of IV ephedrine given at the time of spinal anesthesia, and after a 10 mL/kg lactated Ringers fluid bolus, does not diminish the incidence or severity of hypotension in parturients undergoing cesarean delivery.     

Randomised double‐blind comparison of bolus phenylephrine or ephedrine for treatment of hypotension in women with pre‐eclampsia undergoing caesarean section

Treatment of post‐spinal hypotension during caesarean section assumes special concern in pre‐eclamptic patients due to a compromised fetoplacental circulation and increased risk of placental hypoperfusion. Phenylephrine and ephedrine are the most commonly used vasopressors, although the best choice is still not clear. We studied 80 pre‐eclamptic women with a singleton pregnancy who underwent caesarean section with spinal anaesthesia, and who developed hypotension defined as a decrease in systolic arterial pressure ≥ 20% from baseline or absolute value < 100 mmHg. Women were randomly allocated to receive phenylephrine 50 μg or ephedrine 4 mg boluses for treatment of hypotension. Blood pressure changes following vasopressor administration were similar in both groups, but heart rate remained higher after ephedrine at all time‐points. The primary outcome measure of umbilical artery pH was 7.26 (0.11) in the phenylephrine group and 7.25 (0.09) in the ephedrine group (p = 0.86). The incidence of neonatal acidosis (umbilical artery pH < 7.20) was 9 (22.5%) in the phenylephrine group and 11 (27.5%) in the ephedrine group (p = 0.80). Other secondary outcome measures were comparable. In conclusion, phenylephrine 50 μg and ephedrine 4 mg, administered as intravenous boluses to treat post‐spinal hypotension during caesarean section in pre‐eclamptic patients, resulted in similar fetal acid‐base values, were equally effective in treating hypotension and were associated with good maternal and neonatal outcome.     

A dose-response study of prophylactic intravenous ephedrine for the prevention of hypotension during spinal anesthesia for cesarean delivery

We performed a randomized, double-blinded dose-finding study of IV ephedrine for prophylaxis for hypotension in 80 women who received an IV crystalloid preload and spinal anesthesia for elective cesarean delivery. One minute after the intrathecal injection, patients were given saline control or ephedrine 10, 20, or 30 mg IV for 30 s. Systolic arterial pressure (SAP) in the first 12 min after the spinal injection was greater in the 30-mg group compared with other groups (P < 0.05). Hypotension occurred in 7 patients (35%) in the 30-mg group compared with 19 (95%), 17 (85%), and 16 (80%) patients in the control and 10- and 20-mg groups, respectively (P < 0.0001). Maximum decrease in SAP was smaller in the 30-mg group (mean lowest SAP 87% of baseline, range 58%-105%) compared with other groups (P < 0.01). Reactive hypertension occurred in 9 patients (45%) in the 30-mg group (mean highest SAP 120% of baseline, range 104%-143%) compared with 2 (10%), 1 (5%), and 5 (25%) patients in the other groups (P = 0.009). Heart rate changes, total ephedrine requirement, incidence of nausea and vomiting, and neonatal outcome were similar among groups. The proportion of patients with umbilical arterial pH < 7.2 was 10.5%, 25%, 42%, and 22% in the control, 10-, 20-, and 30-mg groups, respectively (P = 0. 12). We conclude that the smallest effective dose of ephedrine to reduce the incidence of hypotension was 30 mg. However, this dose did not completely eliminate hypotension, nausea and vomiting, and fetal acidosis, and it caused reactive hypertension in some patients. Implications: We investigated different doses of IV ephedrine as prophylaxis for hypotension during spinal anesthesia for cesarean delivery and found that the smallest effective dose was 30 mg. However, this dose did not completely eliminate hypotension, caused reactive hypertension in some patients, and did not improve neonatal outcome.     

心率和脉搏灌注变异指数对剖宫产脊麻后低血压的预测作用

目的探讨HR和脉搏灌注变异指数(PVI)对剖宫产脊麻后低血压的预测作用。方法选择择期脊麻下剖宫产的产妇80例,年龄18~40岁,BMI 20~40kg/m2,ASAⅠ或Ⅱ级。在L3-4间隙行硬腰联合麻醉。记录麻醉前后的HR、PVI、BP和MAP。探讨HR和PVI与脊麻后低血压的相关性。结果与未发生低血压的产妇比较,发生低血压的产妇HR基础值明显增快、PVI基础值明显增大(P 0.05)。HR基础值预测低血压的ROC曲线下面积为0.77(P 0.05),最佳阈值为≥84次/分,预测低血压的敏感度和特异度分别为70.7%和81.8%,阳性预测值和阴性预测值分别为91.1%和51.4%。PVI基础值预测低血压的ROC曲线下面积为0.74(P 0.05),最佳阈值为≥21%,预测低血压的敏感度和特异度分别为44.8%和95.5%,阳性预测值和阴性预测值分别为96.3%和39.2%。HR基础值联合PVI基础值预测低血压的ROC曲线下面积为0.86(P 0.05),最佳阈值为≥86次/分(HR)或≥21%(PVI),预测低血压的敏感度和特异度分别为82.8%和86.4%,阳性预测值和阴性预测值分别为92.5%和66.7%。结论脊麻前较大的心率基础值和脉搏灌注变异指数基础值与剖宫产脊麻后低血压相关,联合使用这两个指标可以用于临床预测剖宫产脊麻后低血压。     

Randomized trial of bolus phenylephrine or ephedrine for maintenance of arterial pressure during spinal anaesthesia for Caesarean section

Thirty-eight healthy women undergoing elective Caesarean section under spinal anaesthesia at term were allocated randomly to receive boluses of either phenylephrine 100 micrograms or ephedrine 5 mg for maintenance of maternal arterial pressure. The indication for administration of vasopressor was a reduction in systolic pressure to < or = 90% of baseline values. Maternal arterial pressure (BP) and heart rate (HR) were measured every minute by automated oscillometry. Cardiac output (CO) was measured by cross-sectional and Doppler echocardiography before and after preloading with 1500 ml Ringer lactate solution and then every 2 min after administration of bupivacaine. Umbilical artery pulsatility index (PI) was measured using Doppler before and after spinal anaesthesia. The median (range) number of boluses of phenylephrine and ephedrine was similar; 6 (1-10) vs 4 (1- 8) respectively. Maternal systolic BP and CO changes were similar in both groups, but the mean [95% CI] maximum percentage change in maternal HR was larger in the phenylephrine group (-28.5 [-24.2, - 32.9]%) than in the ephedrine group (-14.4 [-10.6, -18.2]%). As a consequence atropine was required in 11/19 women in the phenylephrine group compared with 2/19 in the ephedrine group (P < 0.01). Mean umbilical artery pH [95% CI] was higher in the phenylephrine group (7.29 [7.28-7.30]) than in the ephedrine group (7.27 [7.25-7.28]). The results of the present study support the use of phenylephrine for maintenance of maternal arterial pressure during spinal anaesthesia for elective Caesarean section.      

Prophylactic intravenous bolus ephedrine for elective Caesarean section under spinal anaesthesia

BACKGROUND AND OBJECTIVE: To evaluate the efficacy and optimal dose of prophylactic intravenous ephedrine for the prevention of maternal hypotension associated with spinal anaesthesia for Caesarean section. METHODS: After patients had received an intravenous preload of 0.5 L of lactated Ringer's solution, spinal anaesthesia was administered in the sitting position with hyperbaric bupivacaine 2.5 mL 0.5% combined with 25 microg fentanyl. A total of 68 patients were randomized to receive a simultaneous 2 mL bolus intravenously of either 0.9% saline (Group C, n = 20), ephedrine 6 mg (Group E-6, n = 24), or ephedrine 12 mg (Group E-12, n = 22). Further rescue boluses of ephedrine 6 mg were given if systolic arterial pressure fell to below 90 mmHg, greater than 30% below baseline, or if symptoms suggestive of hypotension were reported. RESULTS: There was a significantly higher incidence of hypotension in Group C (60% patients) compared to Group E-12 (27%), but not in Group E-6 (50%). The 95% Confidence Interval for the difference in proportions between Groups C and E-12 was 6-60%, P < 0.05. Fewer rescue boluses of ephedrine were required in Group E-12 compared with Group C (1.8 +/- 1.2 vs. 3.3 +/- 2.1, P < 0.05). There were no significant differences in the incidence of maternal nausea or vomiting, or of neonatal acidaemia between groups. CONCLUSION: A prophylactic bolus of ephedrine 12 mg intravenously given at the time of intrathecal block, plus rescue boluses, leads to a lower incidence of hypotension following spinal anaesthesia for elective Caesarean section compared to intravenous rescue boluses alone.     

Phenylephrine added to prophylactic ephedrine infusion during spinal anesthesia for elective cesarean section

BACKGROUND: Because ephedrine infusion (2 mg/min) does not adequately prevent spinal hypotension during cesarean delivery, the authors investigated whether adding phenylephrine would improve its efficacy. METHODS: Thirty-nine parturients with American Society of Anesthesiologists physical status I-II who were scheduled for cesarean delivery received a crystalloid preload of 15 ml/kg. Spinal anesthesia was performed using 11 mg hyperbaric bupivacaine, 2.5 microg sufentanil, and 0.1 mg morphine. Maternal heart rate and systolic blood pressure were measured at frequent intervals. A vasopressor infusion was started immediately after spinal injection of either 2 mg/min ephedrine plus 10 microg/min phenylephrine or 2 mg/min ephedrine alone. Treatments were assigned randomly in a double-blind fashion. The infusion rate was adjusted according to systolic blood pressure using a predefined algorithm. Hypotension, defined as systolic blood pressure less than 100 mmHg and less than 80% of baseline, was treated with 6 mg ephedrine bolus doses. RESULTS: Hypotension occurred less frequently in the ephedrine-phenylephrine group than in the ephedrine-alone group: 37% versus 75% (P = 0.02). Ephedrine (36+/-16 mg, mean +/- SD) plus 178+/-81 microg phenylephrine was infused in former group, whereas 54+/-18 mg ephedrine was infused in the latter. Median supplemental ephedrine requirements and nausea scores (0-3) were less in the ephedrine-phenylephrine group (0 vs. 12 mg, P = 0.02; and 0 vs. 1.5, P = 0.01, respectively). Umbilical artery pH values were significantly higher in the ephedrine-phenylephrine group than in the group that received ephedrine alone (7.24 vs. 7.19). Apgar scores were similarly good in both groups. CONCLUSION: Phenylephrine added to an infusion of ephedrine halved the incidence of hypotension and increased umbilical cord pH.     

The use of intravenous atropine after a saline infusion in the prevention of spinal anesthesia-induced hypotension in elderly patients

We investigated the efficacy of IV atropine for preventing spinal anesthesia-induced hypotension in elderly patients. Seventy-five patients undergoing transurethral prostate or bladder surgery were randomized to receive either placebo (n = 25), atropine 5 microg/kg (small-dose atropine, n = 25) or atropine 10 microg/kg (large-dose atropine, n = 25) after the induction of spinal anesthesia. All the patients received an IV infusion of 10 mL/kg 0.9% normal saline over 10 min before the induction of anesthesia. The systolic blood pressure decreased in all three groups after spinal anesthesia. There was a significant increase in the mean heart rate in both atropine groups as compared to the placebo group (placebo group: 78 bpm, 95% confidence interval [CI]: 76.6-78.5; small-dose atropine group: 86 bpm, 95% CI 83.9-88.8; large-dose atropine group: 97 bpm, 95% CI 94.5-100.3; P: = 0.001). There was a significant decrease in the incidence of hypotension in patients who received atropine (placebo group: 76%, small-dose atropine group: 52%, large-dose atropine group: 40%, P: = 0.03). The mean dose of ephedrine required was significantly decreased in the atropine groups (placebo group: 12.2 mg [SD= 10.5], small-dose atropine group: 7.4 mg [SD= 10.0], large-dose atropine group: 5.4 mg [SD= 8.7 mg], P: = 0.048). The total amount of IV fluid and number of patients requiring metaraminol in addition to 30 mg of ephedrine were not significantly different among the three groups. Significant side effects, such as confusion, ST segment changes or angina were not detected in any of the patients. We conclude that IV atropine may be a useful supplement to the existing methods in preventing hypotension induced by spinal anesthesia. Implications: IV atropine increases heart rate in a dose-dependent manner in elderly patients undergoing spinal anesthesia. It reduces the incidence of hypotension and the dose of ephedrine required. Small-dose atropine may be a useful supplement in preventing spinal anesthesia-induced hypotension in elderly patients.     

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.     

Patients with severe preeclampsia experience less hypotension during spinal anesthesia for elective cesarean delivery than healthy parturients: a prospective cohort comparison

In this prospective cohort study, we compared the incidence and severity of spinal anesthesia (SA)-associated hypotension in severely preeclamptic (n = 30) versus healthy (n = 30) parturients undergoing cesarean delivery. After the administration of IV fluids, SA was performed with hyperbaric 0.5% bupivacaine, sufentanil, and morphine. Blood pressure (BP) was recorded before and at 2-min intervals for 30 min after SA. Clinically significant hypotension was defined as the need for ephedrine (systolic BP decrease to <100 mm Hg in healthy parturients or 30% decrease in mean BP in both groups). Despite receiving a smaller fluid volume (1653 +/- 331 mL versus 1895 +/- 150 mL; P = 0.005) and a larger bupivacaine dose (10.5 +/- 0.9 mg versus 10.0 +/- 0.7 mg; P = 0.019), the severely preeclamptic patients had a less frequent incidence of clinically significant hypotension (16.6% versus 53.3%; P = 0.006), which was less severe and required less ephedrine. The risk of hypotension was almost six times less in severely preeclamptic patients (odds ratio, 0.17; 95% confidence interval, 0.05-0.58; P = 0.006) than that in healthy patients.