Norepinephrine versus phenylephrine for maintenance of blood pressure during spinal anaesthesia for caesarean delivery - A randomized double blind controlled study

: Currently phenylephrine is a preferred 1 line vasopressor for maintenance of blood pressure during spinal anaesthesia, may be associated with reflex bradycardia and decreased cardiac output, posing risk to mother or foetus. Norepinephrine may be an useful alternative as being potent alpha with weak beta adrenergic agonist activity. : This study compared the effectiveness of prophylactic and treatment boluses of norepinephrine and phenylephrine to maintain systolic blood pressure at or above 80% of baseline value during spinal anesthesia for cesarean delivery with the primary aim to compare cardiac output. Secondary aims were total doses of study drug required, neonatal outcome and perioperative complications.: Total 100, term pregnant women with ASA status II undergoing caesarean delivery under spinal anaesthesia were enrolled in this prospective, double blind controlled study. Patients were randomized to receive prophylactic bolus dose of norepinephrine (6 µg) or phenylephrine (100 µg) immediately after spinal anaesthesia. Systolic blood pressure, cardiac output and heart rate were monitored. Intermittent bolus doses were repeated whenever required. Student ‘t’ test and chi square test were used for analysing the data. : Both the drugs were able to maintain the systolic blood pressure ≥ 80% of baseline (p=0.356). Significant difference observed in cardiac output while comparing both the groups from 3 to 15 minutes after spinal anesthesia (p=0.014). The incidence of bradycardia was lower in norepinephrine group as compared to phenylephrine group (P=0.018). : Norepinephrine is as effective as phenylephrine for maintenance of blood pressure after spinal anaesthesia for caesarean delivery with stable heart rate and cardiac output.

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Randomized Double-blinded Comparison of Norepinephrine and Phenylephrine for Maintenance of Blood Pressure during Spinal Anesthesia for Cesarean Delivery

Anesthesiology ◽

10.1097/aln.0000000000000601 ◽

2015 ◽

Vol 122 (4) ◽

pp. 736-745 ◽

Cited By ~ 103

Author(s):

Warwick D. Ngan Kee ◽

Shara W. Y. Lee ◽

Floria F. Ng ◽

Perpetua E. Tan ◽

Kim S. Khaw

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Cardiac Output ◽

Systolic Blood Pressure ◽

Spinal Anesthesia ◽

Cesarean Delivery ◽

Adrenergic Receptor ◽

Neonatal Outcome ◽

Computer Controlled ◽

Double Blinded

Abstract Background: During spinal anesthesia for cesarean delivery, phenylephrine can cause reflexive decreases in maternal heart rate and cardiac output. Norepinephrine has weak β-adrenergic receptor agonist activity in addition to potent α-adrenergic receptor activity and therefore may be suitable for maintaining blood pressure with less negative effects on heart rate and cardiac output compared with phenylephrine. Methods: In a randomized, double-blinded study, 104 healthy patients having cesarean delivery under spinal anesthesia were randomized to have systolic blood pressure maintained with a computer-controlled infusion of norepinephrine 5 μg/ml or phenylephrine 100 μg/ml. The primary outcome compared was cardiac output. Blood pressure heart rate and neonatal outcome were also compared. Results: Normalized cardiac output 5 min after induction was greater in the norepinephrine group versus the phenylephrine group (median 102.7% [interquartile range, 94.3 to 116.7%] versus 93.8% [85.0 to 103.1%], P = 0.004, median difference 9.8%, 95% CI of difference between medians 2.8 to 16.1%). From induction until uterine incision, for norepinephrine versus phenylephrine, systolic blood pressure and stroke volume were similar, heart rate and cardiac output were greater, systemic vascular resistance was lower, and the incidence of bradycardia was smaller. Neonatal outcome was similar between groups. Conclusions: When given by computer-controlled infusion during spinal anesthesia for cesarean delivery, norepinephrine was effective for maintaining blood pressure and was associated with greater heart rate and cardiac output compared with phenylephrine. Further work would be of interest to confirm the safety and efficacy of norepinephrine as a vasopressor in obstetric patients.

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Dexamethasone blunts postspinal hypotension in geriatric patients undergoing orthopedic surgery: a double blind, placebo-controlled study

BMC Anesthesiology ◽

10.1186/s12871-021-01232-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Tarek M. Ashoor ◽

Noha S. Hussien ◽

Sherif G. Anis ◽

Ibrahim M. Esmat

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Elderly Patients ◽

Spinal Anesthesia ◽

Demographic Data ◽

Volume Overload ◽

Controlled Study ◽

Hyperbaric Bupivacaine ◽

Double Blind ◽

Link Type

Abstract Background Post-spinal anesthesia (PSA) hypotension in elderly patients is challenging. Correction of PSA hypotension by fluids either colloids or crystalloids or by vasoconstrictors pose the risk of volume overload or compromising cardiac conditions. Dexamethasone is used to treat conditions manifested by decrease of peripheral vascular resistance. The research team was the first to test the hypothesis of its role in preventing or decreasing the incidence of PSA hypotension. Methods One hundred ten patients, aged 60 years or more were recruited to receive a single preoperative dose of dexamethasone 8 mg IVI in 100 ml normal saline (D group) (55 patients) 2 h preoperatively, and 55 patients were given placebo (C group) in a randomized, double-blind trial. Variations in blood pressure and heart rate in addition to the needs of ephedrine and/or atropine following spinal anesthesia (SA) were recorded. SA was achieved using subarachnoid injection of 3 ml hyperbaric bupivacaine 0.5%. Results Demographic data and the quality of sensory and motor block were comparable between groups. At 5th, 10th minutes post SA; systolic, diastolic and mean arterial pressures were statistically significant higher in D group. At 20th minutes post SA; the obtained blood pressure readings and heart rate changes didn’t show any statistically significance between groups. The need for ephedrine and side effects were statistically significant lower in D group than C group. Conclusion Post-spinal anesthesia hypotension, nausea, vomiting and shivering in elderly patients were less common after receiving a single preoperative dose of dexamethasone 8 mg IVI than control. Registration number ClinicalTrials.gov Identifier: NCT 03664037, Registered 17 September 2018 - Retrospectively registered, http://www.ClinicalTrial.gov

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Treatment of Hypotension after Hyperbaric Tetracaine Spinal Anesthesia

Anesthesiology ◽

10.1097/00000542-199704000-00009 ◽

1997 ◽

Vol 86 (4) ◽

pp. 797-805 ◽

Cited By ~ 34

Author(s):

Robert F. Brooker ◽

John F. IV Butterworth ◽

Dalane W. Kitzman ◽

Jeffrey M. Berman ◽

Hillel I. Kashtan ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Cardiac Output ◽

Stroke Volume ◽

Systolic Blood Pressure ◽

Spinal Anesthesia ◽

Adrenergic Agonist ◽

Induced Hypotension ◽

Alpha Adrenergic Agonist ◽

Hyperbaric Tetracaine

Background Despite many advantages, spinal anesthesia often is followed by undesirable decreases in blood pressure, for which the ideal treatment remains controversial. Because spinal anesthesia-induced sympathectomy and management with a pure alpha-adrenergic agonist can separately lead to bradycardia, the authors hypothesized that epinephrine, a mixed alpha- and beta-adrenergic agonist, would more effectively restore arterial blood pressure and cardiac output after spinal anesthesia than phenylephrine, a pure alpha-adrenergic agonist. Methods Using a prospective, double-blind, randomized, cross-over study design, 13 patients received sequential infusions of epinephrine and phenylephrine to manage hypotension after hyperbaric tetracaine (10 mg) spinal anesthesia. Blood pressure, heart rate, and stroke volume (measured by Doppler echocardiography using the transmitral time-velocity integral) were recorded at baseline, 5 min after injection of tetracaine, and before and after management of hypotension with epinephrine and phenylephrine. Cardiac output was calculated by multiplying stroke volume x heart rate. Results Five min after placement of a hyperbaric tetracaine spinal anesthesia, significant decrease in systolic (from 143 +/- 6 mmHg to 125 +/- 5 mmHg; P < 0.001), diastolic (from 81 +/- 3 to 71 +/- 3; P < 0.001), and mean (from 102 +/- 4 to 89 +/- 3; P < 0.001) arterial pressures occurred. Heart rate (75 +/- 4 beats/min to 76 +/- 4 beat/min; P = 0.9), stroke volume (115 +/- 17 to 113 +/- 13; P = 0.9), and cardiac output (8.0 +/- 1 l/m to 8.0 +/- 1l/m; P = 0.8) did not change significantly after spinal anesthesia. Phenylephrine was effective at restoring systolic blood pressure after spinal anesthesia (120 +/- 6 mmHg to 144 +/- 5 mmHg; P < 0.001) but was associated with a decrease in heart rate from 80 +/- 5 beats/min to 60 +/- 4 beats/min (P < 0.001) and in cardiac output from 8.6 +/- 0.7 l/m to 6.2 +/- 0.7 l/m (P < 0.003). Epinephrine was effective at restoring systolic blood pressure after spinal anesthesia (119 +/- 5 mmHg to 139 +/- 6 mmHg; P < 0.001) and was associated with an increase in stroke volume from 114 +/- 12 ml to 142 +/- 17 (P < 0.001) and cardiac output from 7.8 +/- 0.6 l/m to 10.8 +/- 1.1 l/m (P < 0.001). Conclusions Epinephrine management of tetracaine spinal-induced hypotension increases heart rate and cardiac output and restores systolic arterial pressure but does not restore mean and diastolic blood pressure. Phenylephrine management of tetracaine spinal-induced hypotension decreases heart rate and cardiac output while restoring systolic, mean, and diastolic blood pressure.

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Dexamethasone blunts postspinal hypotension in geriatric patients undergoing orthopedic surgery: a double blind, placebo-controlled study

10.21203/rs.3.rs-54037/v3 ◽

2021 ◽

Author(s):

Tarek Ashoor ◽

Noha S. Hussien ◽

Sherif G. Anis ◽

Ibrahim M. Esmat

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Elderly Patients ◽

Spinal Anesthesia ◽

Demographic Data ◽

Volume Overload ◽

Controlled Study ◽

Hyperbaric Bupivacaine ◽

Double Blind

Abstract Background: Post-spinal anesthesia (PSA) hypotension in elderly patients is challenging. Correction of PSA hypotension by fluids either colloids or crystalloids or by vasoconstrictors pose the risk of volume overload or compromising cardiac conditions. Dexamethasone is used to treat conditions manifested by decrease of peripheral vascular resistance. The research team was the first to test the hypothesis of its role in preventing or decreasing the incidence of PSA hypotension.Methods: 110 patients, aged 60 years or more were recruited to receive a single preoperative dose of dexamethasone 8 mg IVI in 100 ml normal saline (D group) (55 patients) 2 hours preoperatively, and 55 patients were given placebo (C group) in a randomized, double-blind trial. Variations in blood pressure and heart rate in addition to the needs of ephedrine and/or atropine following spinal anesthesia (SA) were recorded. SA was achieved using subarachnoid injection of 3 ml hyperbaric bupivacaine 0.5%.Results: Demographic data and the quality of sensory and motor block were comparable between groups. At 5th, 10th minutes post SA; systolic, diastolic and mean arterial pressures were statistically significant higher in D group. At 20th minutes post SA; the obtained blood pressure readings and heart rate changes didn’t show any statistically significance between groups. The need for ephedrine and side effects were statistically significant lower in D group than C group. Conclusion: Post-spinal anesthesia hypotension, nausea, vomiting and shivering in elderly patients were less common after receiving a single preoperative dose of dexamethasone 8 mg IVI than control.

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Maternal haemodynamics during labour epidural analgesia with and without adrenaline

Scandinavian Journal of Pain ◽

10.1515/sjpain-2020-0176 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Felix Haidl ◽

Christian Tronstad ◽

Leiv Arne Rosseland ◽

Vegard Dahl

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Cardiac Output ◽

Epidural Analgesia ◽

Systolic Blood Pressure ◽

Circulatory System ◽

Temporal Changes ◽

Double Blind ◽

Nulliparous Women ◽

Labour Epidural Analgesia

Abstract Objectives Labour is one of the most painful experiences in a woman’s life. Epidural analgesia using low-concentration local anaesthetics and lipophilic opioids is the gold standard for pain relief during labour. Pregnancy in general, particularly labour, is associated with changes in maternal haemodynamic variables, such as cardiac output and heart rate, which increase and peak during uterine contractions. Adrenaline is added to labour epidural solutions to enhance efficacy by stimulating the α2-adrenoreceptor. The minimal effective concentration of adrenaline was found to be 2 μg mL−1 for postoperative analgesia. The addition of adrenaline may also produce vasoconstriction, limiting the absorption of fentanyl into the systemic circulation, thereby reducing foetal exposure. However, adrenaline may influence the haemodynamic fluctuations, possibly adding to the strain on the circulatory system. The aim of this study was to compare the haemodynamic changes after application of labour epidural analgesia with or without adrenaline 2 μg mL−1. Methods This was a secondary analysis of a single-centre, randomised double-blind trial. Forty-one nulliparous women in labour requesting epidural analgesia were randomised to receive epidural solution of bupivacaine 1 mg mL−1, fentanyl 2 μg mL−1 with or without adrenaline 2 μg mL−1. The participants were monitored using a Nexfin CC continuous non-invasive blood pressure and cardiac output monitor. The primary outcomes were changes in peak systolic blood pressure and cardiac output during uterine contraction within 30 min after epidural activation. The effect of adrenaline was tested statistically using a linear mixed-effects model of the outcome variables’ dependency on time, adrenaline, and their interaction. Results After excluding three patients due to poor data quality and two due to a malfunctioning epidural catheter, 36 patients (18 in each group) were analysed. The addition of adrenaline to the solution had no significant effect on the temporal changes in peak systolic blood pressure (p=0.26), peak cardiac output (0.84), or heart rate (p=0.91). Furthermore, no significant temporal changes in maternal haemodynamics (peak systolic blood pressure, p=0.54, peak cardiac output, p=0.59, or heart rate p=0.55) were associated with epidural analgesia during 30 min after epidural activation in both groups despite good analgesia. Conclusions The addition of 2 μg mL−1 adrenaline to the epidural solution is not likely to change maternal haemodynamics during labour.

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Blood pressure and cardiac output during caesarean delivery under spinal anaesthesia: a prospective cohort study

BMJ Open ◽

10.1136/bmjopen-2020-046102 ◽

2021 ◽

Vol 11 (6) ◽

pp. e046102

Author(s):

Trond Melbye Michelsen ◽

Christian Tronstad ◽

Leiv Arne Rosseland

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Cardiac Output ◽

Cohort Study ◽

Caesarean Section ◽

Spinal Anaesthesia ◽

Prospective Cohort ◽

Caesarean Delivery ◽

Elective Caesarean Section ◽

Secondary Outcome

ObjectivesWe have previously established a method to measure transfer of nutrients between mother, placenta and fetus in vivo. The method includes measurements of maternal and fetal blood flow by Doppler ultrasound prior to spinal anaesthesia. Spinal anaesthesia affects maternal blood pressure and cardiac output. We aimed to determine the effect of spinal anaesthesia in mothers undergoing an elective caesarean section on blood pressure, heart rate and cardiac output, and whether cardiac output levels were comparable before induction of spinal anaesthesia and before delivery.DesignProspective cohort study.SettingTertiary hospital in Norway.Participants76 healthy women with uneventful pregnancies undergoing an elective caesarean section.InterventionsWe induced spinal anaesthesia with a standard prevention of hypotension including intravenous fluid coloading and phenylephrine infusion.Primary and secondary outcome measuresPrimary outcome measure was maternal cardiac output, and secondary outcome measures were invasive systolic blood pressure and heart rate. We measured heart rate and blood pressure by continuous invasive monitoring with a cannula in the radial artery. Cardiac output was estimated based on continuous arterial waveform. We compared maternal parameters 30 s before induction of spinal anaesthesia to 30 s before delivery.ResultsMedian age at delivery was 34.5 (range 21–43) years and 17 of 76 women were nulliparous. The most prevalent indications were previous caesarean section and maternal request. Among 76 included women, 71 had sufficient data for analysis of endpoints. Median cardiac output was 6.51 (IQR (5.56–7.54) L/min before spinal anaesthesia and 6.40 (5.83–7.56) L/min before delivery (p=0.40)). Median invasive systolic blood pressure increased from 128.5 (120.1–142.7) mm Hg to 134.1 (124.0–146.6) mm Hg (p=0.014), and mean heart rate decreased from 86.0 (SD 13.9) to 75.2 (14.2) (p<0.001).ConclusionsMaternal cardiac output at the time of caesarean delivery is comparable to levels before induction of spinal anaesthesia.Trial registration numberNCT00977769.

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Effects of ingesting a commercial thermogenic product on hemodynamic function and energy expenditure at rest in males and females

Applied Physiology Nutrition and Metabolism ◽

10.1139/h09-113 ◽

2009 ◽

Vol 34 (6) ◽

pp. 1073-1078 ◽

Cited By ~ 12

Author(s):

Colin Wilborn ◽

Lem Taylor ◽

Chris Poole ◽

Brandon Bushey ◽

Laura Williams ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Energy Expenditure ◽

Resting Energy Expenditure ◽

Daily Basis ◽

Controlled Study ◽

Double Blind ◽

Time Points ◽

Significant Difference ◽

Baseline Values

The purpose of this study was to examine the effects of a commercially available thermogenic product (TP) on resting energy expenditure (REE) and hemodynamic variables in a randomized, double-blind, placebo (PL)-controlled study. Eight male (age: 23.0 ± 3.70 years, weight: 95.77 ± 16.44 kg, height: 182.4 ± 7.87 cm) and 10 female (age: 23.6 ± 4.81 years, weight: 67.25 ± 5.74 kg, height: 172.42 ± 10.31 cm) physically active individuals participated in this study. Participants reported to the laboratory on a 10-h fast and performed baseline testing on REE, heart rate, and blood pressure. Participants were then randomly assigned to ingest 3 capsules of either an experimental TP or a vitamin E PL. Criterion variables were then measured at 1-, 2-, and 3-h post ingestion. Data were analyzed by 2-factor analysis of variance (ANOVA) using SPSS, version 16.0 (SPSS Inc., Chicago, Ill.). Supplementation of the TP resulted in a significant main effect for time (p = 0.040) and for interaction (p < 0.01) in REE when compared with PL. Post hoc analysis revealed that there was no significant difference (p > 0.05) between groups at baseline, but the TP group was significantly higher (p < 0.01) than the PL group at 1-, 2-, and 3-h post, with peak values being achieved at 2-h post time point. The TP group also experienced an overall increase in REE by 17.3%, 19.6%, and 15.3% at the 1-, 2-, and 3-h time points, respectively, over baseline values. Conversely, the PL group experienced a reduction in REE by 2.5%, 1.8%, and 0.3% at the same time points compared with baseline values. There was no significant change in heart rate, systolic blood pressure, or diastolic blood pressure in either group. Taken on a daily basis, a TP may increase overall energy expenditure. Caloric expenditure significantly increased at all 3 time points in the TP group, whereas the PL group experienced no change in energy expenditure.

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Dental anxiety in patients undergoing oral surgery and its effects on blood pressure and heart rate

Research Society and Development ◽

10.33448/rsd-v9i8.5536 ◽

2020 ◽

Vol 9 (8) ◽

pp. e316985536

Author(s):

Jaqueline Oliveira Barreto ◽

Julliana Cariry Palhano Freire ◽

Arthur Willian de Lima Brasil ◽

Cristian Statkievicz ◽

Francisley Ávila Souza ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Systolic Blood Pressure ◽

Oral Surgery ◽

Dental Anxiety ◽

Waiting Room ◽

Demographic Questionnaire ◽

Significant Difference ◽

Before And After ◽

Evaluation Anxiety

Objective: To assess dental anxiety in patients undergoing oral surgery, as well as its impact on blood pressure and heart rate. Material and Methods: A total of 233 patients answered a socio-demographic questionnaire and another one based on the Corah dental anxiety scale. Blood pressure and heart rate were assessed at three moments while: patients were in the waiting room, immediately before and after the procedure. Results: This study revealed a prevalence of anxiety of 77.3%. There was a statistically significant difference in mean systolic blood pressure and heart rate at the three moments of the evaluation. Anxiety was prevalent in the sample and was observed from the time in the waiting room until the time when local anesthesia was performed, causing variations in systolic blood pressure and heart rate, anxiety levels decreased after the end of the service. In conclusion, we observed that oral surgery is directly related to increased anxiety, and anxiety is mainly related to the change in heart rate.

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Effect of Evening Bromazepam Administration on Blood Pressure and Heart Rate in Mild Hypertensive Patients

Pharmacology ◽

10.1159/000499371 ◽

2019 ◽

Vol 104 (1-2) ◽

pp. 1-6

Author(s):

Alfredo Costa ◽

Daniele Bosone ◽

Matteo Cotta Ramusino ◽

Giulia Perini ◽

Natascia Ghiotto ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Ambulatory Monitoring ◽

Night Time ◽

Double Blind ◽

Hypertensive Patients ◽

Treatment Groups ◽

Significant Difference ◽

Nocturnal Increase ◽

Mild Hypertensive

Aim: To assess the effects of chronic evening oral administration of bromazepam alone or in combination with propranolol on ambulatory blood pressure (BP) and heart rate (HR) in mild hypertensive subjects. Methods: Thirty-seven mild hypertensive patients after a 2-week placebo period were randomized to bromazepam 3 mg, propranolol 40 mg, bromazepam 3 mg plus propranolol 40 mg or placebo for 2 weeks according to a double-blind, double dummy, cross-over design. After each treatment period, 24-h BP and HR ambulatory monitoring was performed by using a non-invasive device. Results: Ambulatory monitoring showed that during night-time SBP and DBP values were unaffected by bromazepam as compared to placebo, whereas SBP was significantly reduced by propranolol both when taken alone and in combination with bromazepam. HR nocturnal values were significantly reduced by propranolol, whereas they were significantly increased by bromazepan both when taken alone (+11.5%, p < 0.05 vs. placebo) and in combination with propranolol (+12.8%, p < 0.05 vs. propranolol). No significant difference in day-time values of SBP, DBP and HR was observed among the 4 treatment groups. Conclusions: In mild hypertensive patients, evening consumption of bromazepam for a 2-week period did not affect BP, while it increased nocturnal HR. Such an increase was observed both when bromazepam was taken alone and in combination with propranolol, which suggests that it depends on a bromazepam mediated decrease in vagal tone. Whatever the mechanism, the HR nocturnal increase might be of clinical relevance, due to the role of high HR as cardiovascular risk factor, particularly in already at risk hypertensive subjects.

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Variable versus fixed-rate infusion of phenylephrine during cesarean delivery: a randomized controlled trial

BMC Anesthesiology ◽

10.1186/s12871-019-0879-3 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 2

Author(s):

Ahmed Hasanin ◽

Sara Habib ◽

Yaser Abdelwahab ◽

Mohamed Elsayad ◽

Maha Mostafa ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Systolic Blood Pressure ◽

Cesarean Delivery ◽

Controlled Trial ◽

Controlled Study ◽

Lower Systolic Blood Pressure ◽

Randomized Controlled ◽

Phenylephrine Infusion ◽

Infusion Regimen

Abstract Background Phenylephrine is the most commonly used vasopressor for prophylaxis against maternal hypotension during cesarean delivery; however, the best regimen for its administration is not well established. Although variable infusion protocols had been suggested for phenylephrine infusion, evidence-based evaluation of variable infusion regimens are lacking. The aim of this work is to compare variable infusion, fixed on-and-off infusion, and intermittent boluses of phenylephrine for prophylaxis against maternal hypotension during cesarean delivery. Methods A randomized controlled study was conducted, including full-term pregnant women scheduled for elective cesarean delivery. Participants were divided into three groups which received phenylephrine by either intermittent boluses (1.5 mcg/Kg phenylephrine), fixed on-and-off infusion (with a dose of 0.75 mcg/Kg/min), or variable infusion (with a starting dose of 0.75 mcg/Kg/min). The three groups were compared with regard to frequency of: maternal hypotension (primary outcome), second episode hypotension, reactive hypertension, and bradycardia. Other outcomes included heart rate, systolic blood pressure, physician interventions, and neonatal outcomes. Results Two-hundred and seventeen mothers were available for final analysis. The 2 infusion groups showed less incidence of maternal hypotension {26/70 (37%), 22/71 (31%), and (51/76 (67%)} and higher incidence of reactive hypertension compared to the intermittent boluses group without significant differences between the two former groups. The number of physician interventions was highest in the variable infusion group compared to the other two groups. The intermittent boluses group showed lower systolic blood pressure and higher heart rate compared to the two infusion groups; whilst the two later groups were comparable. Conclusion Both phenylephrine infusion regimens equally prevented maternal hypotension during cesarean delivery compared to intermittent boluses regimen. Due to higher number of physician interventions in the variable infusion regimen, the current recommendations which favor this regimen over fixed infusion regimen might need re-evaluation.

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