Norepinephrine versus Ephedrine to Maintain Arterial Blood Pressure during Spinal Anesthesia for Cesarean Delivery: A Prospective Double-blinded Trial

Effects of Systolic Blood Pressure Elevation on Internal Sperm Artery Identification During Microsurgical Subinguinal Varicocelectomy

Microsurgical subinguinal varicocelectomy (MSV) is the gold standard for treating varicoceles. Preservation of the internal spermatic arteries (ISAs) during MSV is important for sperm production. This study aimed to evaluate the safety and efficacy of elevating systolic blood pressure (SBP) using MSV. Data from 252 consecutive adult male patients were retrospectively reviewed. The patients were divided into two groups: a traditional group that underwent conventional MSV (n = 134) and a modified group that underwent MSV with a transiently elevated SBP of 140-160 mm Hg (n = 118). Arterial identification time, unilateral operative time, number of ISAs, arterial injury rate, and other postoperative indicators, including postoperative complications and sperm parameters, were compared between the groups. All the procedures were successful. The arterial identification and unilateral operative times were significantly shorter in the modified group (31.34 ± 10.44 vs. 42.94 ± 12.39 min and 61.48 ± 8.78 vs. 76.35 ± 12.33 min, p < .01, respectively). Intraoperatively, the number of preserved ISAs was significantly higher in the modified group (1.92 ± 0.53 vs. 1.45 ± 0.32, p < .01). The arterial injury rate did not differ significantly between the groups (2.74% vs. 0%, respectively). Compared with preoperative values, sperm parameters improved significantly 6 months postoperatively. Significant differences in semen parameters or postoperative complications were not observed between the groups. Elevated intraoperative SBP can be used to rapidly, safely, and effectively identify ISAs, increase the number of retained spermatic arteries, and markedly reduce the operative time for MSV.

Evaluation of the early use of norepinephrine in major abdominal surgery on medical and surgical postoperative complications: study protocol for a randomised controlled trial (EPON STUDY)

BACKGROUND

Post-induction anaesthesia often promotes intraoperative hypotension (IOH) that can worsen postoperative outcomes. This study aims to assess the benefit of norepinephrine versus ephedrine at the induction of anaesthesia to prevent postoperative complications following major abdominal surgery by preventing IOH.

METHODS AND ANALYSIS

The EPON STUDY is a prospective single-centre randomised controlled trial with the planned inclusion of 500 patients scheduled for major abdominal surgery at the Amiens University Hospital. The inclusion criteria are patients aged over 50 years weighing more than 50 kg with an American Society of Anesthesiologists physical status score of ≥2 undergoing major abdominal surgery under general anaesthesia. Patients are allocated either to the intervention group (n=250) or the standard group (n=250). In the intervention group, the prevention of post-induction IOH is performed with norepinephrine (dilution to 0.016 mg/mL) using an electric syringe pump at a rate of 0.48 mg/h (30 mL/h) from the start of anaesthesia and then titrated to achieve the haemodynamic target. In the control group, the prevention of post-induction IOH is performed with manual titration of ephedrine, with a maximal dose of 30 mg, followed by perfusion with norepinephrine. In both groups, the haemodynamic target to maintain is a mean arterial pressure (MAP) of 65 mm Hg or 70 mm Hg for patients with a medical history of hypertension. An intention-to-treat analysis will be performed. The primary outcome is the Clavien-Dindo score assessed up to 30 days postoperatively. The secondary endpoints are the length of hospital stay and length of stay in an intensive care unit/postoperative care unit; postoperative renal function; postoperative cardiovascular, respiratory, neurological, haematological and infectious complications at 1 month; and volume of intraoperative vascular filling and mortality at 1 month.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the committee of protection of the persons of Ile de France in May 2021 (number 21 05 41). The authors will be involved in disseminating the research findings (through attending conferences and co-authoring papers). The results of the study will be disseminated via peer-reviewed publications and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

NCT05276596.

Consensus on the Southeast Asian management of hypotension using vasopressors and adjunct modalities during cesarean section under spinal anesthesia

BACKGROUND AND AIMS

This consensus statement presents a comprehensive and evidence-based set of guidelines that modify the general European or US guidelines for hypotension management with vasopressors during cesarean delivery. It is tailored to the Southeast Asian context in terms of local human and medical resources, health system capacity, and local values and preferences.

METHODS AND RESULTS

These guidelines were prepared using a methodological approach. Two principal sources were used to obtain the evidence: scientific evidence and opinion-based evidence. A team of five anesthesia experts from Vietnam, the Philippines, and Thailand came together to define relevant clinical questions; search for literature-based evidence using the MEDLINE, Scopus, Google Scholar, and Cochrane libraries; evaluate existing guidelines; and contextualize recommendations for the Southeast Asian region. Furthermore, a survey was developed and distributed among 183 practitioners in the captioned countries to gather representative opinions of the medical community and identify best practices for the management of hypotension with vasopressors during cesarean section under spinal anesthesia.

CONCLUSIONS

This consensus statement advocates proactive management of maternal hypotension during cesarean section after spinal anesthesia, which can be detrimental for both the mother and fetus, supports the choice of phenylephrine as a first-line vasopressor and offers a perspective on the use of prefilled syringes in the Southeast Asian region, where factors such as healthcare features, availability, patient safety, and cost should be considered.

Comparison of the Effect of Intravenous Bolus Norepinephrine and Ephedrine on Prevention of Post Spinal Hypotension in Cesarean Section: a Randomized Double-Blind Clinical Trial

Background:Currently, cesarean section is performed under spinal anesthesia. Hypotension is the most common complication of spinal anesthesia. This study aimed to compare the effect of intravenous bolus norepinephrine and ephedrine on prevention of post spinal hypotension in cesarean section. Methods:The present study was a double-blind clinical trial, in which 50 pregnant women aged 18-46 years, with ASA class I and II, were selected for cesarean section under spinal anesthesia and randomly assigned to two groups, one receiving norepinephrine (group A) and the other one ephedrine (group B). Immediately after spinal anesthesia, patients in group A received 5 μg of intravenous norepinephrine and those in group B 10 mg of intravenous ephedrine. The incidence of hypotension, bradycardia, mean systolic and diastolic blood pressure, and mean heart rate were recorded in a checklist. Patients with hypotension and bradycardia received 10 mg of ephedrine and 0.5 mg of atropine, respectively, and finally the amount of ephedrine and atropine was also recorded. Data were analyzed in SPSS, version 21 at a confidence level of 95%. Results:Hypotension had a frequency of 24% and 40% (P = 0.364) and the dose of ephedrine used to treat that condition was 15.0±8.37 and 18.18±7.51 mg (P = 0.434) in the norepinephrine and ephedrine groups, respectively. The mean heart rate was significantly lower in the norepinephrine group than the ephedrine one (P <0.001). Conclusion:Both norepinephrine and ephedrine were effective in preventing hypotension during cesarean section under spinal anesthesia, but tachycardia was less common with norepinephrine. Trial registration: The present study was registered on 17 May 2019 in the Iranian Clinical Trial Center (https://www.irct.ir) Identifier: IRCT20120915010841N17.

Effectiveness of Prophylactic Bolus Ephedrine Versus Norepinephrine for Management of Postspinal Hypotension during Elective Caesarean Section in Resource Limited Setting: A Prospective Cohort Study

Background. Spinal anaesthesia for caesarean section is the preferred technique since it provides better maternal safety and neonatal outcome compared to general anaesthesia. Hypotension is the most common complication after spinal anaesthesia. The study aims to determine the effectiveness of a prophylactic bolus dose of norepinephrine and ephedrine on the management of postspinal hypotension during caesarean section. Method. An institutional-based prospective cohort study was conducted on 84 pregnant women undergoing elective caesarean section. Based on the responsible anaesthetist’s postspinal hypotension management plan, patients were divided into two groups. Those patients who received ephedrine are grouped into the ephedrine (EPH, n = 42) group, and patients who received norepinephrine are grouped under the norepinephrine group (NE, n = 42) by data collectors. After aseptic technique, spinal anaesthesia was administered with 0.5% (3 ml) bupivacaine using a 23G spinal needle. During spinal anaesthesia, a prophylactic bolus dose of 10 mg (2 ml) EPH or 16 g (2 ml) NE was given based on management plan of the shift anaesthetist. Mean arterial pressure (MAP), the heart rate (HR), number of boluses of vasopressor used, incidence of nausea and vomiting, and the Apgar score of babies at 1 and 5 min between the groups were recorded. Results. The norepinephrine group had a statistically significant higher MAP compared to the ephedrine group in the first 10 and 15 min ( $p<0.05$ ) of the study period. Thereafter, there was no statistically significant difference in MAP between the groups until the end of the study period ( $p>0.05$ ). The ephedrine group had a statistically significant higher heart rate throughout the procedure compared to the norepinephrine group ( $p<0.05$ ). The norepinephrine group required a lower bolus number of vasopressors compared to the ephedrine group to maintain blood pressure. The Apgar scores of all babies at 1 and 5 min were above seven. Significant differences regarding maternal complications (nausea and vomiting) between the groups were not detected (nausea, $p=0.21$ and vomiting, $p=0.092$ ). Conclusion. Norepinephrine can be used instead of ephedrine to keep a pregnant mother’s blood pressure stable during a caesarean section under spinal anaesthesia without causing harm to the mother or baby. Trial registration. ClinicalTrials.gov Identifier: NCT05522088 (Date of registration: 30/08/22).

Blood vessel assessment using computed tomography : Effects of ephedrine on uterine artery

Background: Ephedrine increased blood pressure due to the contractile properties of resistance vessels. Excessive contraction of the uterine arteries might cause fetal distress. This study was to determine the diameter of the uterine artery of female New Zealand rabbits after the administration of different doses of ephedrine using CT.

Methods: Thirty-two rabbits were randomly divided into a control group (Group C), low dosage group (Group L), medium dosage group (Group M) and high dosage group (Group H). Normal saline and doses corresponding to the human dose of 7.5, 15 and 30 mg of ephedrine were injected respectively. The marginal ear and uterine artery diameters were measured 5, 10, 15, 30, and 45 min after injection using CT, and the hemodynamic changes were recorded.

Results: The increase in mean arterial pressure in group M (p = 0.009), and H (p = 0.013) was higher than that in group C. Compared with group C, substantial contraction of the marginal ear artery was observed at the three doses of ephedrine. There were no differences in the uterine artery diameter among groups L, M and C, However, in Group H, a significant contraction of the uterine artery compared with the other groups (p < 0.001) was observed.

Discussion: CT can be used to evaluate the effects of drugs on organs and blood vessels. Ephedrine can not only constrict the peripheral blood vessels but also do not affect the uterine artery at a dose of 15 mg or less. However, the dose should not exceed 30 mg, which may cause severe uterine artery depression.

A Prospective Randomized Study Comparing the Bolus Doses of Norepinephrine and Phenylephrine for the Treatment of Spinal Induced Hypotension in Cesarean Section

Background: Spinal anesthetic-induced hypotension is the most worrisome complication for patients undergoing cesarean section under spinal anesthesia. The present study compares norepinephrine and phenylephrine bolus for the treatment of hypotension during spinal anesthesia for cesarean section.

Methods: One hundred twenty- six women aged between 22 and 40 years with singleton pregnancy classified to the American Society of Anesthesiologists (ASA) physical class I and II posted for elective cesarean section under spinal anesthesia were randomly divided into two groups of 63 each. Group I patients received phenylephrine 50 mcg (microgram) as an intravenous bolus, and Group II received 4 mcg of norepinephrine as an intravenous bolus to treat spinal hypotension.

Results: On comparing the demographic data of the patients in terms of age, weight, height, ASA Grade, level of block and surgery time no significant differences were found between the groups. Similarly, the fetal parameters were found to be not significantly different between the groups. However, the number of bolus doses of vasopressors required for the treatment of spinal-induced hypotension was significantly reduced in Group II (p=0.02). The frequency of bradycardia was found to be higher in patients who were given phenylephrine as compared to patients administered noradrenaline boluses (p=0.03). Five (7.93%) patients had shivering in Group I, while similar episodes were observed in 10 (15.87%) patients (p=0.05). Moreover, no significant difference was observed in comparing the heart rate and mean arterial pressure between the groups.

Conclusion: Intermittent boluses of norepinephrine are found to be effective in the management of spinal‑induced hypotension during caesarean section.

Comparison of two vasopressor protocols for preventing hypotension post-spinal anesthesia during cesarean section: a randomized controlled trial

Background:

Norepinephrine infusion decreases hypotension after spinal anesthesia during cesarean section. This study aimed to compare the efficacy of norepinephrine infusion and ephedrine bolus against post-spinal hypotension in parturients.

Methods:

In this double-blinded, randomized controlled clinical trial, parturients scheduled for elective cesarean section were randomly allocated to receive norepinephrine infusion (0.05 μg·kg⁻¹·min⁻¹) just before spinal anesthesia continuing for 30 min or ephedrine bolus (0.15 mg/kg) just before spinal anesthesia. A rescue bolus (5 μg norepinephrine for the norepinephrine group, and 5 mg ephedrine for the ephedrine group) was administered whenever hypotension occurred. Our primary outcome was the incidence of hypotension within 30 min of spinal anesthesia administration. Secondary outcomes included maternal and neonatal outcomes 30 min after spinal block, and neonatal cerebral oxygenation 10 min after birth.

Results:

In total, 190 patients were enrolled; of these patients, 177 were included in the final analysis. Fewer patients suffered hypotension in the norepinephrine group than in the ephedrine group (29.5% vs. 44.9%, odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.28–0.95, P = 0.034). Moreover, the tachycardia frequency was lower in the norepinephrine group than in the ephedrine group (OR: 0.22, 95% CI: 0.11–0.44, P < 0.001), and patients suffered less nausea and vomiting (OR: 0.28, 95% CI: 0.11–0.70, P = 0.004). There was no difference in Apgar scores and umbilical arterial blood gas analysis between the two groups. However, neonatal cerebral regional saturations were significantly higher after birth in the norepinephrine group than in the ephedrine group (mean difference: 2.0%, 95% CI: 0.55%–3.45%, P = 0.008).

Conclusion:

In patients undergoing elective cesarean section with spinal anesthesia, norepinephrine infusion compared to ephedrine bolus resulted in less hypotension and tachycardia, and exhibited potential neonatal benefits.

Trial Registration:

ClinicalTrials.gov, NCT02542748; https://clinicaltrials.gov/ct2/show/record/NCT02542748

Intravenous norepinephrine and mephentermine for maintenance of blood pressure during spinal anaesthesia for caesarean section: An interventional double-blinded randomised trial

Background and Aims:

Spinal anaesthesia induced hypotension (SAIH) and bradycardia may prove deleterious to both parturient and baby, hence vasopressors play a vital role in their management. Recent studies on norepinephrine as rescue vasopressor during subarachnoid block (SAB) enlighten its role for SAIH. This randomised double-blind trial was conducted to compare the effect of intermittent intravenous boluses of norepinephrine and frequently used mephentermine for management of SAIH in caesarean section (CS) to prove whether norepinephrine produces comparable effects or superior to mephentermine.

Methods:

After approval from Institutional Ethics Committee and registration in Clinical Trials Registry India (CTRI/2019/06/019652), 256 parturients posted for elective CS under SAB were randomly allocated into Group-N and Group-M (n = 84) using chit system, who received boluses of intravenous norepinephrine 8μg and mephentermine 6mg for SAIH, respectively. Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), Response%, Apgar score and maternal complications were analysed.

Results:

The changes in SBP and DBP were comparable in both the groups. It was significantly low after SAB compared to baseline and significantly high compared to 1^st hypotensive value in both the groups throughout the study period (<0.0001). HR was comparable for initial 10 min, thereafter it was significantly high in Group-M (<0.0001) till 40 min. Response% after the first bolus was significantly high in Group-N (59.30n ± 29.21 vs 39.78 ± 25.6; P = <0.0001).

Conclusion:

Intravenous norepinephrine is better than mephentermine with respect to high response% and stable maternal HR although both are equally effective in maintaining blood pressure following SAIH during elective CS.

A Clinical Trial on the Effects of Different Regimens of Phenylephrine on Maternal Hemodynamic After Spinal Anesthesia for Cesarean Section

Background

Phenylephrine is used to prevent and treat hypotension during spinal anesthesia for cesarean delivery.

Objectives

The present study aims to investigate the effects of different regimens of phenylephrine on blood pressure of candidates for the cesarean section.

Methods

In this double-blind, randomized clinical trial, a total of 120 candidates of elective cesarean delivery under spinal anesthesia was randomly categorized into three groups. Groups 1, 2, and 3 received bolus and prophylactic saline (control group), prophylactic bolus phenylephrine (100 µg), and prophylactic phenylephrine infusion (50 µg/min), respectively. The incidence of hypotension, maternal hemodynamics, hypertension, rescue phenylephrine dose, nausea, and vomit were compared between the groups.

Results

In all the three groups, the incidence of nausea and vomit, bradycardia, hypertension, and neonatal Apgar score were not statistically different (P > 0.05). However, the adjuvant phenylephrine dose requirement was remarkably different. Moreover, the mean systolic blood pressure differed significantly in the second and 7th minutes after the spinal block (P < 0.05). 35% in the first group, 15% in the second group, and 2.5% in the third group had hypotension (P = 0.001). Apart from the first measurement after spinal anesthesia, the mean heart rate showed no significant difference between the groups.

Conclusions

The use of prophylactic phenylephrine infusion is recommended to control the optimal blood pressure in parturients undergoing cesarean section after spinal anesthesia.

Determination of the ED50 and ED95 of intravenous bolus of norepinephrine for the treatment of hypotension during spinal anesthesia for cesarean delivery

Norepinephrine is considered as a potential alternative for blood pressure stabilization during spinal anesthesia for cesarean delivery, as it maintains a better maternal heart rate and cardiac output compared with phenylephrine. However, its use as a bolus dose for hypotension treatment remains largely unexplored. Therefore, the present study investigated the ED50 and ED95 of norepinephrine as a bolus for maternal hypotension during cesarean delivery. In the present prospective trial, 42 patients were enrolled for elective delivery under spinal anesthesia. The dose of norepinephrine was decided by the up-and-down sequential allocation method (UDM) with an initial dose of 0.075 µg/kg and a 0.025 µg/kg increment. The 42 patients received a bolus of norepinephrine when systolic blood pressure fell to <80% of baseline. The ED50 was calculated by the sequential method and the probit regression model. The ED95 was then calculated using the probit regression model. The ED50 of norepinephrine, which was determined by the UDM, was 0.067 µg/kg (95% CI, 0.056-0.081). The probit regression model calculated an ED50 of 0.072 µg/kg (95% CI, 0.056-0.088) and an ED95 of 0.121 µg/kg (95% CI, 0.1-0.207). In summary, the present results suggested the ED50 of a bolus norepinephrine for preventing hypotension in elective CD is 0.067 µg/kg (95% CI, 0.056-0.081), with an ED95 of 0.121 µg/kg (95% CI, 0.1-0.207).

Comparison of norepinephrine and phenylephrine boluses for the treatment of hypotension during spinal anaesthesia for caesarean section - A randomised controlled trial

Background and Aims:

Hypotension following spinal anaesthesia for caesarean section is common in spite of adequate fluid loading. Phenylephrine is the recommended drug to treat spinal hypotension during caesarean section. Recently, norepinephrine boluses are being suggested as an alternative to phenylephrine boluses. The aim of our study was to compare the effectiveness of bolus doses of norepinephrine with phenylephrine to treat spinal hypotension during caesarean section.

Methods:

Fifty patients undergoing elective caesarean section under spinal anaesthesia were randomly assigned into two groups. Group P patients received phenylephrine 50 μg as an intravenous bolus and group N received 4 μg of norepinephrine as intravenous bolus to treat spinal hypotension. The primary objective of our study was to compare the number of bolus doses of norepinephrine or phenylephrine required to treat spinal hypotension. The secondary objectives were to compare the incidence of bradycardia, hypertension, nausea and vomiting in mother and foetal outcomes.

Results:

The number of boluses of vasopressors required to treat hypotension was significantly lower in group N (1.40 ± 0.577 vs. 2.28 ± 1.061, P = 0.001). The frequency of bradycardia was high in group P, but this difference was not statistically significant (4%vs. 20%, P = 0.192). Maternal complications such as nausea and vomiting and shivering were comparable between the groups. The foetal parameters were also comparable between the two groups.

Conclusion:

Intermittent boluses of norepinephrine are effective in the management of spinal-induced hypotension during caesarean section. The neonatal outcomes were similar in both the groups. Norepinephrine boluses can be considered as an alternative to phenylephrine boluses.

A Comparative Study of Bolus Norepinephrine, Phenylephrine, and Ephedrine for the Treatment of Maternal Hypotension in Parturients with Preeclampsia During Cesarean Delivery Under Spinal Anesthesia

Background

This study aimed to compare the efficacy and safety of bolus norepinephrine, phenylephrine, and ephedrine in parturient with preeclampsia who had hypotension during cesarean delivery under spinal anesthesia.

Material/Methods

One hundred and sixty-six parturient women with preeclampsia who had a baseline systolic blood pressure (SBP) <80% during spinal anesthesia for cesarean section were divided into three treatment groups; bolus norepinephrine 4 μg (group N) (n=56), phenylephrine 50 μg (group P) (n=55), and ephedrine 4 mg (group E) (n=55). Primary outcomes included overall SBP and heart rate (HR) until delivery. Secondary outcomes included the incidence of tachycardia (HR >120 bpm), bradycardia (HR <60 bpm), hypertension (SBP >120% baseline), number of boluses of vasopressor required and episodes of hypotension, maternal side effects, and neonatal outcome.

Results

Overall HR in group N was significantly increased compared with group P (80.5±12 vs. 76.6±6.9 bpm; P=0.04), and significantly lower compared with group E (80.5±12 vs. 84.9±7.1 bpm; P=0.02). Parturients in group N had fewer episodes of bradycardia compared with group P (3.6% vs. 21.8%; RR=0.26l; 95% CI, 0.07–0.73; P=0.004) and fewer episodes of tachycardia compared with group E (16.1% vs. 36.4%; RR 0.54; 95% CI, 0.29–0.90; P=0.02).

Conclusions

A bolus dose of norepinephrine showed similar efficacy to phenylephrine but improved maternal and neonatal safety in parturients with preeclampsia with hypotension during cesarean section under spinal anesthesia.

Role of Nitric Oxide in the Cardiovascular and Renal Systems

The gasotransmitters are a family of gaseous signaling molecules which are produced endogenously and act at specific receptors to play imperative roles in physiologic and pathophysiologic processes. As a well-known gasotransmitter along with hydrogen sulfide and carbon monoxide, nitric oxide (NO) has earned repute as a potent vasodilator also known as endothelium-derived vasorelaxant factor (EDRF). NO has been studied in greater detail, from its synthesis and mechanism of action to its physiologic, pathologic, and pharmacologic roles in different disease states. Different animal models have been applied to investigate the beneficial effects of NO as an antihypertensive, renoprotective, and antihypertrophic agent. NO and its interaction with different systems like the renin–angiotensin system, sympathetic nervous system, and other gaseous transmitters like hydrogen sulfide are also well studied. However, links that appear to exist between the endocannabinoid (EC) and NO systems remain to be fully explored. Experimental approaches using modulators of its synthesis including substrate, donors, and inhibitors of the synthesis of NO will be useful for establishing the relationship between the NO and EC systems in the cardiovascular and renal systems. Being a potent vasodilator, NO may be unique among therapeutic options for management of hypertension and resulting renal disease and left ventricular hypertrophy. Inclusion of NO modulators in clinical practice may be useful not only as curatives for particular diseases but also for arresting disease prognoses through its interactions with other systems.

Comparison of Ephedrine vs. Norepinephrine in Treating Anesthesia-Induced Hypotension in Hypertensive Patients: Randomized Double-Blinded Study

Background

Hypotension is a common problem in general anesthesia. Maintaining the mean arterial pressure by choosing a vasopressor with minimal complications is still discussed in various surgeries.

Objectives

The aim of this study is comparison of ephedrine versus norepinephrine in treating anesthesia-induced hypotension in hypertensive patients in spinal surgery in a randomized double-blinded study.

Methods

This randomized, double-blinded study was approved by Iran University of Medical Sciences, operating room of medical center. Data collection was completed between Jan to Dec 2017. Inclusion criteria included age between 20 and 75 years, history of high blood pressure (a patient who has been treated for maximum 5 years with a anti hypertensive medication), and patients under general anesthesia in spinal surgery. The exclusion criteria were based on American Society of Anesthesiologists physical status of 3 or higher, history of arrhythmia, heart valve disease, cerebrovascular disease, kidney failure, beta-blocker use and diabetes, as well as intra operative massive blood loss. After initiation of anesthesia, when the pressure reaches less than 60, the patient entered the protocol and simultaneously administration of 5 mL/kg serum crystalloid and vasopressor. Patients were randomized to the ephedrine group (n = 28) who received 5 mg ephedrine intravenous (i.v.) or norepinephrine Group (n = 28) who received 10 µg (i.v.) bolus norepinephrine at anesthesia-induced hypotension. The administration of 5 mL/kg serum crystalloid and vasopressor was simultaneous. If the mean arterial pressure (MAP) had not reached 60 mmHg, the same dose should be repeated at a maximum of three or more times at five-minute intervals in the ephedrine group and at two minutes intervals in the norepinephrine group. All parameters were collected before and at the end of administration anesthesia drug and during episodes of hypotension. Hemodynamic variables, frequency of hypotension, and total number of vasopressors doses during anesthesia were recorded and analyzed.

Results

The mean number of hypotension times, the number of vasopressors doses in the first hypotension, the total number of doses consumed during the anesthesia, and heart rate at the end of anesthesia were lower in the norepinephrine group (P) respectively. MAP, 5 minutes after the first episode of hypotension and MAP at the end of anesthesia were higher in norepinephrine group.

Conclusions

Norepinephrine is more effective than ephedrine in maintenance of MAP in hypertensive patients undergoing spinal surgery under general anesthesia.