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 Table of Contents  
ORIGINAL ARTICLE
Year : 2016  |  Volume : 30  |  Issue : 2  |  Page : 116-120

Prophylactic intravenous ephedrine for prevention of hypotension in cesarean section during spinal anesthesia: A comparative study


1 Department of Anaesthesiology, RIMS, Imphal, Manipur, India
2 Department of Anaesthesiology, JNIMS, Imphal, Manipur, India

Date of Web Publication24-May-2016

Correspondence Address:
Takhelmayum Hemjit Singh
Department of Anaesthesiology, Regional Institute of Medical Sciences, Imphal - 795 004, Manipur
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-4958.182922

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  Abstract 

Background: Spinal anesthesia is the most common preferred technique for cesarean delivery. However, it is associated with hypotension which is detrimental to both the mother and fetus. The study has been undertaken to determine the effect of bolus intravenous ephedrine in ameliorating spinal-induced hypotension. Materials and Methods: Fifty primiparous parturients scheduled for cesarean section were randomly allocated into two groups of 25 patients each: Group 1 (study) and Group 2 (control) to receive either 1 ml of 5 mg bolus intravenous ephedrine or equal volume of normal saline, respectively, just after 10 mg of 0.5% intrathecal bupivacaine. Results: Significant fall in systolic blood pressure from its baseline value occurs at all time intervals in both the groups, except up to the 4 th min in the ephedrine group. The incidences of hypotension between the two groups were 60% and 72% in the ephedrine and control group, respectively (P > 0.05). Conclusion: Prophylactic use of intravenous ephedrine did not significantly decrease the incidence of maternal hypotension.

Keywords: Cesarean section, hypotension, intravenous bolus ephedrine, spinal anesthesia


How to cite this article:
Singh TH, Thokchom RS, Sinam M, Nongthonbam R, Devi MB, Singh KM. Prophylactic intravenous ephedrine for prevention of hypotension in cesarean section during spinal anesthesia: A comparative study. J Med Soc 2016;30:116-20

How to cite this URL:
Singh TH, Thokchom RS, Sinam M, Nongthonbam R, Devi MB, Singh KM. Prophylactic intravenous ephedrine for prevention of hypotension in cesarean section during spinal anesthesia: A comparative study. J Med Soc [serial online] 2016 [cited 2021 Apr 12];30:116-20. Available from: https://www.jmedsoc.org/text.asp?2016/30/2/116/182922


  Introduction Top


Spinal anesthesia is often used for both elective and emergency cesarean section. Anesthesia-related maternal mortality is decreased when general anesthesia is avoided. [1] The proportion of women undergoing cesarean section has been increasing steadily. [2]

Nowadays, spinal anesthesia is the preferred technique for lower abdominal surgery. [3] However, hypotension is the most common side effect of neuraxial blocks in the obstetric patients due to sympathetic blockade. In the pregnant patient, spinal-induced hypotension along with compression of the inferior vena cava by the gravid uterus further impedes venous return, and if untreated, this process may lead to maternal hypotension and uterine hypoperfusion. [4] Therefore, regional anesthesia for elective cesarean section is often the preferred option of caregivers when balancing risks and benefits to the mother and the fetus.

Several techniques used for preventing hypotension include intravenous fluid prehydration, sympathomimetic drugs, and physical methods such as leg bindings and compression stockings. Despite all these measures, approximately 25% of patients still experience hypotension episodes. [5]

Ephedrine is an alkaloid with potent alpha and beta agonist and acts both by direct as well as indirect mechanism. It has been the vasopressor of choice the vasopressor of choice because it has been shown to have a more protective effect on uterine blood flow and perfusion pressure than α-adrenergic agonists in gravid ewes and humans. [6] However, it has been found out that ephedrine administration is associated with significant increases in fetal heart rate and beat-to-beat variability. These changes are dose related and are not associated with fetal asphyxia as judged by the measurement of fetal scalp blood pH or Apgar scores. [7]

Prophylactic ephedrine given by standard infusion set was more effective than crystalloid prehydration in the prevention of hypotension during spinal anesthesia for elective cesarean section. [8] However, there are limited studies regarding the use of intravenous bolus prophylactic ephedrine for the prevention of spinal-induced hypotension in parturients.

Hence, the present study is planned to study the effect of intravenous bolus ephedrine in ameliorating hypotension in cesarean delivery following intrathecal bupivacaine injection.


  Materials and methods Top


The study was a randomized, prospective, double-blind one conducted in the Department of Anesthesiology, at a Tertiary Care Centre, Imphal, Manipur, during October 2013-September 2015. After taking approval from the Institutional Ethics Committee and written informed consent from 50 primiparous term parturients, aged 18-40 years and American Society of Anesthesiologist I, scheduled for the elective cesarean section, these 50 parturients were assigned into two groups of 25 patients each by computer-generated randomization, namely Group 1 (study group) to receive 1 ml of 5 mg injection ephedrine intravenously and Group 2 (control group) to receive an equal volume of normal saline intravenously, immediately after the subarachnoid block with 10 mg of 0.5% injection bupivacaine (heavy). Parturients refusing regional anesthesia, contraindications to spinal anesthesia, fetal anomalies, known allergy to any of drugs used in this study, pregnancy-induced hypertension or parturients with systolic blood pressure (BP) >140 mm Hg, history of diabetes mellitus, cardiovascular, or cerebrovascular, and any chronic diseases were excluded from the study.

A thorough preanesthetic evaluation was done a day before the scheduled operation to all patients, and tablet ranitidine 150 mg orally was advised the night before surgery.

On the day of operation, injection metoclopramide 10 mg and injection ranitidine 50 mg were given intravenously, 20 min before the induction of spinal anesthesia.

Upon arrival of the patient at the operation theater, baseline parameters were recorded with the help of multichannel cardiac monitor. Preloading was done with injection ringer lactate solution 15 mg/kg body weight about 15 min before the intended time of intrathecal drug administration.

Under strict aseptic and antiseptic precautions, lumbar puncture was performed at L 3 -L 4 intervertebral space using midline approach with a 25 gauge quincke spinal needle in the lateral decubitus position and 10 mg of 0.5% injection bupivacaine was administered intrathecally. Immediately, either 1 ml of 5 mg injection ephedrine or an equal volume of normal saline was given intravenously on the parturients according to the computer-generated randomization method. The study solution was prepared by a person not involved in the study.

The hemodynamic parameters such as heart rate, systolic BP, percentage saturation of oxygen (SpO 2 ), and electrocardiogram were recorded at 1 min intervals till the delivery of the baby and thereafter at 5 min intervals until the end of the surgery. Intravenous fluid was administered in the form of ringer lactate at the rate of 10 ml/kg body weight per hour. A decrease in systolic BP of more than 20% from the baseline was considered as hypotension and treated with rapid infusion of ringer lactate and 5 mg intravenous ephedrine, and heart rate <60 beats per minute or bradycardia was also treated with intravenous 0.6 mg atropine sulfate. Apgar scores of the babies were recorded at 1 and 5 min.

Sample size was calculated based on the study by Vercauteren et al., [9] where 23 patients in each group were determined with the alpha error of 0.05, beta value of 0.05 with power of 0.95, and rounded of to 25 patients considering any dropouts.

The data collected were entered in a computer and statistical analysis was performed using the Statistical Package for Social Sciences (SPSS Inc., version 21, Chicago, IL, USA). Continuous variables were compared by independent sample t-test, and Chi-square test was applied for categorical variables and P < 0.05 was considered statistically significant.


  Results Top


All the 50 patients completed the study protocol. The patient demographics such as age, height, and weight were comparable and insignificant (P > 0.05) in the two groups, as shown in [Table 1].
Table 1: The distribution and comparison of demographic variables in the two groups

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The systolic BP fell significantly from its baseline value at different time intervals in both the groups, except up to the 4 th min in the ephedrine group where it was insignificant, as shown in [Table 2] and [Figure 1]. However, the fall was more in the control group and was statistically significant till the 4 th min when compared with the ephedrine group. Furthermore, the mean highest and lowest systolic BPs even though higher in the ephedrine group were statistically not significant.
Figure 1: The comparison of mean systolic blood pressure and mean heart rate in the two groups

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Table 2: The distribution and comparison of systolic blood pressure in the two groups (mmHg)

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The heart rate, as shown in [Figure 1], increased from the baseline value in both the groups up to a maximum at around 6 th min and thereafter decreased to approach its baseline value at around 40 min. These trends in the fall of heart rate in the two groups were comparable (P > 0.05).

The incidences of hypotension episodes, reactive hypertension, number of patients requiring rescue ephedrine, total dose of rescue ephedrine (mgs), bradycardia, nausea or vomiting, and average time of delivery of babies of the two groups are shown in [Table 3]. The ephedrine group had insignificant lower incidence, i.e., 15 (60%) episodes of hypotension than the control group, i.e., 18 (72%), which required rescue injection ephedrine. There was no incidence of reactive hypertension in both the groups. Furthermore, the ephedrine group recorded 15 (60%) patients as against 18 (72%) patients in the control group requiring rescue ephedrine (P > 0.05). The ephedrine group required lesser amount of rescue ephedrine (3.01 ± 0.5 mg) than the control group (4.04 ± 0.4 mg), where the difference was statistically not significant (P > 0.05). The average time intervals of delivery in the two groups were 4.92 ± 0.64 and 4.88 ± 0.66 min and comparable (P > 0.05). There were no incidences of bradycardia episodes, nausea, and vomiting in the two groups.
Table 3: Comparison of hemodynamic data and other variables in the two groups

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The comparison of neonatal outcome data such as Apgar score at 1 min, 5 th min, and umbilical cord blood pH, as shown in [Table 4], was comparable in the two groups and no significant difference was observed (P > 0.05).
Table 4: The distribution and comparison of neonatal outcome data in the two groups

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  Discussion Top


Hypotension, which is the decrease in systolic BP below 20% from the baseline value, is the most common serious adverse effect of spinal anesthesia for cesarean delivery, with an incidence reported in the literature up to 80%. Various strategies for preventing hypotension have been investigated and tried as it may have detrimental maternal and neonatal effects. Many interventions such as pelvic tilt, leg elevation and wrapping, and the prophylactic administration of fluids or vasopressors have been proposed and used to reduce the incidence of maternal hypotension. Despite all these measures, approximately 25% of patients still experience hypotensive episodes. [10]

Ephedrine is not a potent arterial vasoconstrictor; it maintains BP mainly by increasing cardiac output and heart rate. [11] This may be the reason that high doses of prophylactic intravenous ephedrine are associated with side effects such as reactive hypertension, which is usually considered as systolic BP >140 mmHg. [9]

In our study, the insignificant variations in the weight, height, and age of the parturients between the groups [Table 1] emphasize the fact that this study was made blind on the weight, height, and age of the parturients. In other words, parturients considered for our study who received ephedrine 5 mg or and an equal volume of normal saline were comparable as regard to their age, weight, and height.

We observed a significant fall from the baseline value of systolic and diastolic BP at all the time intervals in both the groups in our study, except up to the early 4 th min in the ephedrine group, which may be due to hypotension protective effect of bolus ephedrine. Our findings are different from those conducted by Ngan Kee et al., [10] Vercauteren et al., [9] and Iqbal et al., [12] where they recorded insignificant fall in BP which may be due to lower dose of bupivacaine (6.6 mg with Sufentanil) against 10 mg in our study, even though they used 5 mg bolus ephedrine. Again, Ngan Kee et al. [10] and Iqbal et al. [12] used higher doses of ephedrine.

The incidences of hypotension in our study are 60% and 72% in the ephedrine and control groups, respectively. Even though the ephedrine group recorded lower incidence of hypotension as compared to the control group, it was not statistically significant. This finding is in accordance with the study conducted by Simon et al. [13] where the incidence of hypotension was 63.8% in those patients receiving 10 mg prophylactic intravenous ephedrine, but the result is in contrast to the study conducted by different workers such as Kol et al. [14] recorded 38.1% incidence of hypotension with intravenous bolus 25 mg ephedrine for 60 s, Ngan Kee et al. [10] recorded 35%, 85%, and 80% with 30 mg, 20 mg, and 10 mg, respectively, of bolus ephedrine, and Iqbal et al. [12] recorded 53.3%, 13.3%, and 3.3% with 10 mg, 15 mg, and 20 mg, respectively, of bolus ephedrine and this might be due to the deployment of higher doses of intravenous ephedrine as against 5 mg in our study. Again, lower incidence of hypotension (8%) was recorded with bolus 5 mg of ephedrine in the study by Vercauteren et al., [9] which may be due to the lower dose of intrathecal bupivacaine (6.6 mg with sufentanil), as also supported by lower incidence of hypotension in their control group. Kang et al. [15] also suggested that 20 mg prophylactic ephedrine infusion was safe and effective for the prevention of maternal BP during spinal anesthesia for cesarean delivery. Our insignificant incidence of hypotension in the ephedrine group may be due to the lower dose of the drug used in our study. Moreover, Thiangtham and Asampinwat [16] also opined that ephedrine 18 mg infusion does not prevent hypotension (85.9% incidence), as continuous infusion for 10 min might not attain the target plasma concentration of the drug.

There were no incidences of reactive hypertension in both the groups in our study. These findings are corroborative with that done by Vercauteren et al. [9] Higher incidence of reactive hypertension was also noticed in the study using 30 mg IV bolus ephedrine conducted by Ngan Kee et al. [10] However, in the study using 15 mg bolus ephedrine by Iqbal et al., [12] the incidence of reactive hypotension was 46.7%. This can be explained due to higher doses of intravenous ephedrine in their studies as against 5 mg in our study.

The average vasopressor consumption in our study was reduced in the ephedrine group (3.01 ± 0.5 mg) compared to control (4.044 ± 0.4 mg), even though statistically not significant, and this may be due to the effect of bolus ephedrine in the study group. The incidence of fall in BP was maximum during the first 4-6 min following subarachnoid block and we observed that vasopressor used was maximum in this period. This corresponds to the immediate sympathetic block after intrathecal injection. Ngan Kee et al. [10] also opined that vasopressor requirements were reduced till the time of delivery only and the average median dose was 0 versus 10 mg of ephedrine (P < 0.001) in their study using vasopressor infusion.

In our study, the heart rate increased considerably for around 6 min corresponding to the interval of fall in BP and there was an insignificant increase in heart rate in all measured intervals between the two groups. Similar findings were found by Ngan Kee et al. [10] and Mercier et al. [17] where they observed heart rate changes with an increased trend for around 10 min. This change was attributed to causes such as anxiety, aortocaval compression, and hypotension.

Neonatal outcome as evidenced by Apgar score and umbilical cord blood pH was almost similar in both the groups in our study. Wright et al. [7] opined that ephedrine has an inherent property of beta-adrenoceptor-stimulating activity and its ability to cross the placenta can affect the neonatal and fetal heart rate. However, in the study conducted in a dose range of 10-30 mg by Ngan Kee et al., [10] the potential vasoconstrictive effects of ephedrine may have less detrimental effect on uteroplacental blood flow than the effects of hypotension. Our study also used the lower dose of the drug (5 mg) which may be the reason of similar Apgar scores and umbilical cord blood pH in both the groups. This was also shown in the study of Vercauteren et al. [9]

The percentage SpO 2 in both the groups was comparable, which was also recorded similarly in the study conducted by Kol et al. [14] The incidence of side effects such as nausea and vomiting was not seen in both the groups in our study.

Our study was not without any limitations. Hypotension due to blood loss and experience of the operating surgeon in controlling bleeding might be a confounding factor. Left lateral tilt by keeping a wedge done to all the parturients undergoing cesarean delivery might also be a confounding factor. Block height was not equal in all the patients, and further study is required to determine the exact dose response.


  Conclusion Top


Prophylactic use of intravenous ephedrine 5 mg bolus did not significantly decrease the incidence of maternal hypotension even though it was lower than the control group. We suggest that doses higher than 5 mg have to be tried for effective control of hypotension.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Hawkins JL, Koonin LM, Palmer SK, Gibbs CP. Anesthesia-related deaths during obstetric delivery in the United States, 1979-1990. Anesthesiology 1997;86:277-84.  Back to cited text no. 1
    
2.
Notzon FC. International differences in the use of obstetric interventions. JAMA 1990;263:3286-91.  Back to cited text no. 2
    
3.
Birnbach DJ, Browne IM. Anesthesia for obstetrics. In: Miller RD, Eriksson LI, Fleiser LA, Wiener-Kronish JP, Young WL, editors. Miller′s Anesthesia. 7 th ed. Philadelphia, USA: Churchill Livingstone Elsevier; 2010. p. 2203-40.  Back to cited text no. 3
    
4.
Frolich MA. Crystalloid Prehydration Time to Change Our Practice? A Current Review. Available from: target="_blank" href="http://www.soap.org/media/newsletters/spring2003/crystal.htm". [Last accessed on 2015 Aug 01].  Back to cited text no. 4
    
5.
Ngan Kee WD, Khaw KS, Ng FF. Prevention of hypotension during spinal anesthesia for cesarean delivery: An effective technique using combination phenylephrine infusion and crystalloid cohydration. Anesthesiology 2005;103:744-50.  Back to cited text no. 5
    
6.
Ralston DH, Shnider SM, DeLorimier AA. Effects of equipotent ephedrine, metaraminol, mephentermine, and methoxamine on uterine blood flow in the pregnant ewe. Anesthesiology 1974;40:354-70.  Back to cited text no. 6
    
7.
Wright RG, Shnider SM, Levinson G, Rolbin SH, Parer JT. The effect of maternal administration of ephedrine on fetal heart rate and variability. Obstet Gynecol 1981;57:734-8.  Back to cited text no. 7
    
8.
Desalu I, Kushimo OT. Is ephedrine infusion more effective at preventing hypotension than traditional prehydration during spinal anaesthesia for caesarean section in African parturients? Int J Obstet Anesth 2005;14:294-9.  Back to cited text no. 8
    
9.
Vercauteren MP, Coppejans HC, Hoffmann VH, Mertens E, Adriaensen HA. Prevention of hypotension by a single 5-mg dose of ephedrine during small-dose spinal anesthesia in prehydrated cesarean delivery patients. Anesth Analg 2000;90:324-7.  Back to cited text no. 9
    
10.
Ngan Kee WD, Khaw KS, Lee BB, Lau TK, Gin T. A dose-response study of prophylactic intravenous ephedrine for the prevention of hypotension during spinal anesthesia for cesarean delivery. Anesth Analg 2000;90:1390-5.  Back to cited text no. 10
    
11.
Critchley LA, Stuart JC, Conway F, Short TG. Hypotension during subarachnoid anaesthesia: Haemodynamic effects of ephedrine. Br J Anaesth 1995;74:373-8.  Back to cited text no. 11
    
12.
Iqbal MS, Ishaq M, Masood A, Khan MZ. Optimal dose of prophylactic intravenous ephedrine for spinal induced hypotension during cesarean section. Anaesth Pain Intensive Care 2010;14:71-5.  Back to cited text no. 12
    
13.
Simon L, Provenchère S, de Saint Blanquat L, Boulay G, Hamza J. Dose of prophylactic intravenous ephedrine during spinal anesthesia for cesarean section. J Clin Anesth 2001;13:366-9.  Back to cited text no. 13
    
14.
Kol IO, Kaygusuz K, Gursoy S, Cetin A, Kahramanoglu Z, Ozkan F, et al. The effects of intravenous ephedrine during spinal anesthesia for cesarean delivery: A randomized controlled trial. J Korean Med Sci 2009;24:883-8.  Back to cited text no. 14
    
15.
Kang YG, Abouleish E, Caritis S. Prophylactic intravenous ephedrine infusion during spinal anesthesia for cesarean section. Anesth Analg 1982;61:839-42.  Back to cited text no. 15
    
16.
Thiangtham K, Asampinwat T. Intravenous ephedrine infusion for prophylaxis of hypotension during spinal anaesthesia for cesarean section. Songkha Med J 2009;27:291-300.  Back to cited text no. 16
    
17.
Mercier FJ, Riley ET, Frederickson WL, Roger-Christoph S, Benhamou D, Cohen SE. Phenylephrine added to prophylactic ephedrine infusion during spinal anesthesia for elective cesarean section. Anesthesiology 2001;95:668-74.  Back to cited text no. 17
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]


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