A comparative study of infusions of phenylephrine, ephedrine and phenylephrine plus ephedrine on maternal haemodynamics in elective caesarean section

Effect of phenylephrine versus ephedrine on the incidence of postoperative delirium in olderly adults undergoing knee arthroplasty under general anesthesia: a single-center trial

In addition to stabilizing blood pressure (BP), ephedrine and phenylephrine have distinct effects on regional cerebral oxygen saturation (rSO2). However, whether its effect on rSO2 affects the occurrence of postoperative delirium (POD) remains unclear. Therefore, the aim of this study is to compare the effects of ephedrine and phenylephrine for BP maintenance on the incidence of POD in olderly adults who underwent knee arthroplasty under general anesthesia. One hundred twenty patients who were between 60 and 90 years old and underwent knee arthroplasty were included in this study. The patients were randomly divided into two groups: the ephedrine group and the phenylephrine group. After anesthesia induction, ephedrine and phenylephrine were continuously infused to maintain the intraoperative mean arterial pressure within the normal range (baseline mean arterial pressure ± 20%). The primary outcome measures included the incidence of POD within 1-3 days after surgery. The incidence of POD on the first day after surgery was lower in the ephedrine group than in the phenylephrine group (33% vs. 7%, P < 0.001). However, there was no significant difference in the incidence of POD between the two groups on the second and third postoperative days. Compared with the phenylephrine group, the ephedrine group experienced significantly greater cardiac output (CO) and rSO2 (P < 0.05).Clinical Trials Registry: ChiCTR2200064849, principal investigator: Changjian Zheng.

Techniques for preventing hypotension during spinal anaesthesia for caesarean section

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury).

OBJECTIVES

To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE.

MAIN RESULTS

We included 125 studies involving 9469 women. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids) Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloid Fewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.69, 95% CI 0.58 to 0.81; 2009 women; 27 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women; very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.98, 95% CI 0.54 to 1.78, 5 studies, 413 women; very low-quality evidence), nausea and/or vomiting (average RR 0.89, 95% CI 0.66 to 1.19, 14 studies, 1058 women, I² = 29%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 10 studies, 730 babies; very low-quality evidence). Ephedrine versus phenylephrine There were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus control Ondansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus control Lower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42, 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lying There was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence). Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections. External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration.

AUTHORS' CONCLUSIONS

While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.

The influence of the infusion of ephedrine and phenylephrine on the hemodynamic stability after subarachnoid anesthesia in senior adults - a controlled randomized trial

Background

We studied the influence of ephedrine or phenylephrine infusion administered immediately after spinal anesthesia (SA) on hemodynamics in elderly orthopedic patients.

Methods

A prospective, randomized, double-blind, placebo-controlled study.

After a subarachnoid injection of 15 mg of levobupivacaine, the participants received an infusion of either ephedrine 20 mg (E group), phenylephrine 250 mcg (P group) or saline (C group) within 30 min. We measured blood pressure, cardiac index (CI) and heart rate (HR) from 15 min before to 30 min after SA.

Results

Seventy patients were included in the final analysis. At the end of measurements, mean arterial pressure (MAP) decreased significantly after SA in comparison to the baseline value in the C group but was maintained in the P and E group, with no significant differences between the groups. CI decreased after SA in the C group, was maintained in the P group, and increased significantly in the E group with significant differences between the C and E group (p = 0.049) also between the P and E (p = 0.01) group at the end of measurements. HR decreased significantly after SA in the C and P group but was maintained in the E group, with significant differences between the P and E group (p = 0.033) at the end of measurements.

Conclusions

Hemodynamic changes after SA in elderly orthopedic patients can be prevented by an immediate infusion of phenylephrine or ephedrine. In addition to maintaining blood pressure, the ephedrine infusion also maintains HR and increases CI after SA.

Trial registration

ISRCTN registry with registration number ISRCTN44377602, retrospectively registered on 15 June 2017.

Prevention of hypotension after spinal anaesthesia for caesarean section: a systematic review and network meta-analysis of randomised controlled trials

Spinal anaesthesia for caesarean section commonly causes maternal hypotension. This systematic review and network meta-analysis compared methods to prevent hypotension in women receiving spinal anaesthesia for caesarean section. We selected randomised controlled trials that compared an intervention to prevent hypotension with another intervention or inactive control by searching MEDLINE and Embase, Web of Science to December 2018. There was no language restriction. Two reviewers extracted data on trial characteristics, methods and outcomes. We assessed risk of bias for individual trials (Cochrane tool) and quality of evidence (GRADE checklist). We assessed 109 trials (8561 women) and 12 different methods that resulted in 30 direct comparisons. Methods ranked by OR (95%CI) from most effective to least effective were: metaraminol 0.11 (0.04-0.26); norepinephrine 0.13 (0.06-0.28); phenylephrine 0.18 (0.11-0.29); leg compression 0.25 (0.14-0.43); ephedrine 0.28 (0.18-0.43); colloid given before induction of anaesthesia 0.38 (0.24-0.61); angiotensin 2, 0.12 (0.02-0.75); colloid given after induction of anaesthesia 0.52 (0.30-0.90); mephentermine 0.09 (0.01-1.30); crystalloid given after induction of anaesthesia 0.78 (0.46-1.31); and crystalloid given before induction of anaesthesia 1.16 (0.76-1.79). Phenylephrine caused maternal bradycardia compared with control, OR (95%CI) 0.23 (0.07-0.79). Ephedrine lowered umbilical artery pH more than phenylephrine, standardised mean difference (95%CI) 0.78 (0.47-1.49). We conclude that vasopressors should be given to healthy women to prevent hypotension during caesarean section with spinal anaesthesia.

Preventive intramuscular phenylephrine in elective cesarean section under spinal anesthesia: A randomized controlled trial

BACKGROUND

Phenylephrine is the first-line vasoactive drug in the cesarean section under spinal anesthesia. The rate of hypotension remains high after intravenous preventive use of phenylephrine. However, few studies have investigated the effect of preventive intramuscular phenylephrine via a longer period of usage on fetal and maternal outcomes.

METHODS

A total of 99 healthy parturients undergoing elective cesarean delivery were randomly allocated into three groups: M group (preventive intramuscular use of 5 mg phenylephrine), V group (preventive intravenous use of 100 μg phenylephrine), and P group (0.9% normal saline placebo). Rescue phenylephrine, ephedrine and atropine were used intraoperatively to adjust blood pressure and heart rate. The primary outcome was umbilical artery pH.

RESULTS

Significant differences in umbilical artery pH (M group: 7.32 ± 0.05 versus V group: 7.25 ± 0.04 versus P group: 7.21 ± 0.03, P < 0.05), fetal acidosis (M group: 3% [n = 33] versus V group: 15% [n = 33] versus P group: 30% [n = 33], P = 0.01) and maternal intraoperative hypotension (M group: 12% [33] versus V group: 39% [33] versus P group: 73% [33], P < 0.0001) were identified among the groups. Multiple linear regression analysis demonstrated that treating arms, neonatal birthweight and the interval from the end of anesthesia to baby delivery were associated with umbilical artery pH.

CONCLUSION

Compared with the preventive intravenous use of phenylephrine and placebo, preventive intramuscular phenylephrine exhibited a better neonatal acid-base status and more stable maternal hemodynamics in elective cesarean under spinal anesthesia.

Phenylephrine vs ephedrine in cesarean delivery under spinal anesthesia: A systematic literature review and meta-analysis

BACKGROUND

In the past 20 years, many studies compared phenylephrine with ephedrine to prevent or treat hypotension in elective or emergency cesarean delivery and parturients with pre-eclampsia. A meta-analysis of the abovementioned trials is needed.

METHODS

Several databases (PubMed, Embase, Web of Science and Cochrane Library) were searched from inception to April 2018 for trials comparing phenylephrine with ephedrine in cesarean delivery. The primary outcome is the incidence of maternal hypotension.

RESULTS

Thirty-six trials (2439 patients) with elective cesarean delivery, three trials (400 patients) with emergency cesarean delivery and three trials (192 patients) with parturients with pre-eclampsia were included and analyzed. The incidence of hypotension did not differ in the elective surgery group (relative risk 0.83, 95% CI 0.66 to 1.05), emergency surgery group (relative risk 1.02, 95% CI 0.87 to 1.19) and pre-eclamptic parturients group (relative risk 0.93, 95% CI 0.63 to 1.37). The phenylephrine group had a higher incidence of bradycardia and lower incidences of tachycardia and nausea or vomiting in all three patient groups. The phenylephrine group also had lower fetal acidosis rate, higher umbilical artery and vein pH values and less base excess in the elective surgery. The abovementioned outcomes were similar in the emergency surgery group and the pre-eclampsia group. Publication bias for hypotension was detected. However, the trim and fill method demonstrated that the publication bias had little impact on hypotension. Trial sequential analysis of hypotension in elective surgery showed that this meta-analysis lacked a sufficient cumulative sample size and that further studies should be included.

CONCLUSION

Phenylephrine and ephedrine were both effective in maintaining hemodynamic balance. Newborns benefited more from phenylephrine in elective cesarean delivery, but not in emergency cesarean delivery or in parturients with pre-eclampsia. More trials should be included to achieve more conclusive results.

The Effect of Prophylactic Infusion of Combined Ephedrin and Phenylephrine on Maternal Hemodynamic after Spinal Anesthesia for Cesarean Section: A Randomized Clinical Trial

Several techniques have been proposed to prevent hypotension in obstetric patients. Ephedrine and phenylephrine are individually used to prevent maternal hypotension; however, each has its own drawbacks. Some researchers have reported that the infusion of combined ephedrine and phenylephrine immediately after spinal anesthesia for cesarean delivery reduces the incidence of maternal hypotension. Other studies have indicated that the combination is not superior to the infusion of an individual agent. The present study aimed to evaluate the effect of prophylactic infusion of ephedrine and phenylephrine before the induction of spinal anesthesia for cesarean section on maternal hemodynamic. In a randomized, double-blinded clinical trial study, 90 pregnant women that underwent elective cesarean delivery under spinal anesthesia were recruited. Before the spinal anesthesia, the infusion of combined ephedrine and phenylephrine during 15 minutes (study group) or serum NaCl 0.9% (placebo group) was performed. Hemodynamic parameters and fetal blood gas were recorded. The data were analyzed using the SPSS software, version 16.0. The results showed that hypotension and bradycardia after spinal anesthesia were less in the study group. The need for vasopressors and inotropes to treat hypotension, nausea, and vomiting were higher in the placebo group. First- and fifth-minute Apgar scores were higher in the study group. The prophylactic infusion of low-dose ephedrine and phenylephrine before spinal anesthesia for cesarean delivery can be used to decrease the frequency and severity of maternal hypotension and its side effects to the mother and neonate.

TRIAL REGISTRATION NUMBER

IRCT201401277013N6.

Techniques for preventing hypotension during spinal anaesthesia for caesarean section

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury).

OBJECTIVES

To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE.

MAIN RESULTS

We included 126 studies involving 9565 participants. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids)Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloidFewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.68, 95% CI 0.58 to 0.80; 2105 women; 28 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women;very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.99, 95% CI 0.55 to 1.79, 6 studies, 509 women; very low-quality evidence), nausea and/or vomiting (average RR 0.83, 95% CI 0.61 to 1.13, 15 studies, 1154 women, I² = 37%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 11 studies, 826 babies; very low-quality evidence). Ephedrine versus phenylephrineThere were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus controlOndansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus controlLower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42 , 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lyingThere was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence).Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections.External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration.

AUTHORS' CONCLUSIONS

While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.

A Comparison of Intravenous Ephedrine or Phenylephrine, for Prevention of Postspinal Hypotension during Elective Lower Abdominal Surgery: A Randomized, Double-blind Case-control Study

BACKGROUND

In this randomized, double-blinded case-control study, we investigated the intravenous effects of ephedrine or phenylephrine on prevention of post-spinal hypotension in elective lower abdominal surgery under spinal anesthesia.

MATERIALS AND METHODS

One hundred and thirty-five patients, American Society of Anesthesiologists physical status I or II candidate for elective lower abdominal surgery under spinal anesthesia were randomized to three groups (45 each). According to their allocated group, patients received either ephedrine 2.5 mg (E group), phenylephrine (P group) 25 mic as vasopressor or the same volume of saline normal as placebo (S group) immediately after the spinal anesthesia. hemodynamic parameters, and complications were recorded.

RESULTS

Patients' demographics were similar in all the groups. The mean systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP and also heart rate were similar over time for groups E and P (P > 0.05). The incidence of reactive hypertension was more in group E than group P and placebo (P < 0.05). The incidence of nausea and vomiting were significantly lower in groups E and P in comparison with placebo (P < 0.05).

CONCLUSION

Although the mean fall of SBP and DBP were significantly less in groups E and P compared with placebo but we did not find significant differences in prophylactic use of ephedrine or phenylephrine for prevention of post-spinal hypotension in elective lower abdominal surgery. Vasopressors infusion have added benefit of lower incidence of nausea and vomiting.

Randomized double-blind comparison of ephedrine and phenylephrine for management of post-spinal hypotension in potential fetal compromise

BACKGROUND

Most studies comparing phenylephrine and ephedrine have been conducted during elective caesarean sections in healthy mothers with no fetal compromise. The effect of vasopressors on fetal outcome may differ between healthy and compromised fetuses. There has been little research into the effect of phenylephrine and ephedrine, when used for management of post-spinal hypotension in the presence of potential fetal compromise.

METHODS

Healthy women with a singleton pregnancy undergoing emergency caesarean section for fetal compromise under spinal anaesthesia were studied. One-hundred-and-six consecutive subjects, who developed hypotension after spinal anaesthesia, were randomly allocated to two groups of 53 each, to receive either phenylephrine (Group P) or ephedrine (Group E). For every systolic blood pressure reading <100mmHg patients received phenylephrine 100μg or ephedrine 8mg depending on group allocation. Umbilical blood gas parameters and Apgar scores were recorded.

RESULTS

There was no statistically significant difference in umbilical arterial pH (P=0.79), umbilical venous pH (P=0.98), other blood gas parameters, incidence of fetal acidosis (P=1.00) and Apgar scores. The number of hypotensive episodes, vasopressor doses for treatment of the first hypotensive episode and the total number of doses used during the study period were comparable. The median [IQR] total number of doses of phenylephrine and ephedrine used before delivery were 2 [1-2] and 2 [1-2], respectively (P=0.67). More patients receiving ephedrine (24.5%) developed tachycardia than those receiving phenylephrine (3.8%) (P=0.004). Bradycardia was more common with phenylephrine, with 39.6% of patients in Group P as compared to only 1.9% of patients in Group E developing a heart rate <60beats/min after vasopressor administration (P=0.001).

CONCLUSIONS

Both phenylephrine 100μg and ephedrine 8mg boluses are equally efficacious when treating post-spinal hypotension in the presence of potential fetal compromise. However, phenylephrine may be a better choice in the presence of maternal tachycardia.

Comparison of Prophylactic Infusion of Phenylephrine with Ephedrine for Prevention of Hypotension in Elective Cesarean Section under Spinal Anesthesi: A Randomized Clinical Trial

BACKGROUND

Spinal anesthesia is an accepted technique in elective cesarean sections. However, hypotension, resulted from sympathectomy is a common problem, especially in pregnant women. Prevention of this complication by sympathomimetic agents is of potential clinical significance. The aim of this study is to compare the effect of prophylactic infusion of Phenylephrine versus Ephedrine in the prevention of hypotension during spinal anesthesia in elective cesarean section.

METHODS

Eighty-three patients were enrolled in this study and randomly divided into three groups. Group Ph received phenylephrine infusion, group E received ephedrine infusion while group P were delivered placebo. Vital signs (blood pressure, heart rate, and arterial oxygen saturation) were recorded throughout the surgery. Maternal and neonatal perioperative complications were also controlled and recorded.

RESULTS

There was an insignificant difference in demographic data between the groups. Systolic and diastolic blood pressures were higher in the phenylephrine group than control, but not higher than the ephedrine group. Maternal dysrhythmias were more common in ephedrine and phenylephrine groups than the control group. Vomiting was more common in ephedrine group (P<0.05). In addition, the fifth-minute Apgar score of neonates was higher in phenylephrine and ephedrine groups than the control group (P<0.05). Neonates of phenylephrine group had less acidosis than the other groups.

CONCLUSION

Prophylactic infusion of phenylephrine can effectively decrease spinal anesthesia related hypotension without any significant complication for mother or her fetus.

TRIAL REGISTRATION NUMBER

IRCT2012120911700N1.

Prophylactic phenylephrine for caesarean section under spinal anaesthesia: systematic review and meta-analysis

We conducted a systematic review to determine the harm and benefit associated with prophylactic phenylephrine for caesarean section under spinal anaesthesia. We included 21 randomised controlled trials with 1504 women. The relative risk (95% CI) of hypotension with phenylephrine infusion – as defined by authors – before delivery was 0.36 (0.18–0.73) vs placebo, p = 0.004; 0.58 (0.39–0.88) vs an ephedrine infusion, p = 0.009; and 0.73 (0.55–0.96) when added to an ephedrine infusion, p = 0.02. After delivery, the relative risks of hypotension and nausea and vomiting with phenylephrine compared with placebo were 0.37 (0.19–0.71), p = 0.003, and 0.39 (0.17–0.91), p = 0.03, respectively. There was no evidence that hypertension, bradycardia or neonatal endpoints were affected. Phenylephrine reduced the risk for hypotension and nausea and vomiting after spinal doses of bupivacaine generally exceeding 8 mg, but there was no evidence that it reduced other maternal or neonatal morbidities.

Effect of phenylephrine vs. ephedrine on frontal lobe oxygenation during caesarean section with spinal anesthesia: an open label randomized controlled trial

Background: During caesarean section spinal anesthesia may provoke maternal hypotension that we prevent by administration of phenylephrine and/or ephedrine. Phenylephrine is however reported to reduce the near infrared spectroscopy-determined frontal lobe oxygenation (ScO₂) but whether that is the case for patients exposed to spinal anesthesia is not known.

Objectives: To evaluate the impact of phenylephrine vs. ephedrine on ScO₂during caesarean section with spinal anesthesia in a single center, open-label parallel-group study with balanced randomization of 24 women (1:1). Secondary aims were to compare the effect of the two drugs on maternal hemodynamics and fetal heart rate.

Intervention: Ephedrine (0.8–3.3 mg/min) vs. phenylephrine infusion (0.02–0.07 mg/min).

Results: For the duration of surgery, administration of ephedrine maintained ScO₂ (compared to baseline +2.1 ± 2.8%; mean ± SE, while phenylephrine reduced ScO₂ (−8.6 ± 2.8%; p = 0.005) with a 10.7% difference in ScO₂between groups (p = 0.0106). Also maternal heart rate was maintained with ephedrine (+3 ± 3 bpm) but decreased with phenylephrine (−11 ± 3 bpm); difference 14 bpm (p = 0.0053), but no significant difference in mean arterial pressure (p = 0.1904) or CO (p = 0.0683) was observed between groups. The two drugs also elicited an equal increase in fetal heart rate (by 19 ± 3 vs. 18 ± 3 bpm; p = 0.744).

Conclusion: In the choice between phenylephrine and ephedrine for maintenance of blood pressure during caesarean section with spinal anesthesia, ephedrine maintains frontal lobe oxygenation and maternal heart rate with a similar increase in fetal heart rate as elicited by phenylephrine.

Trial registration: Clinical trials NCT 01509521 and EudraCT 2001 006103 35.

Recurrent intraoperative silent ST depression responding to phenylephrine

Intraoperative myocardial ischemia is attributed to decreased myocardial oxygen supply. We present an unusual case of recurrent, symptomless inferior wall ischemia in an apparently healthy male with no history of coronary artery disease after a spinal block. The recurring episodes were linked to tachycardia and presented with significant ST depression in Lead II with reciprocal elevation in lead aVL. The episodes responded to phenylephrine and subsided without residual sequelae.