Protecting effect of gabapentin for nausea and vomiting in the surgery of cesarean after spinal anesthesia.

BACKGROUND: Nausea and vomiting are the most common effects after cesarean delivery with spinal anesthesia that was associated with problems such as pneumonia, delay in patient discharge, electrolyte abnormalities, and the maternal dissatisfaction.
OBJECTIVES: The aim of this study was to evaluate the effects of gabapentin in preventing nausea and vomiting after spinal anesthesia in cesarean delivery. PATIENTS AND METHODS: This study as a double-blind clinical trial was done on 200 candidates of cesarean with a random distribution. Patients without cardiovascular diseases and in 1 and 2 American Society of Anesthesiologists were divided into two groups. Treatment group received 600 mg capsule (gabapentin) 1 h before surgery and the control group received placebo. The severity of nausea and vomiting were evaluated according to 4 Scores every hour to 4 h after the withdrawal of mother from the recovery section.
RESULTS: In this study, there is no significant difference in demographic information between these two groups. In the 1(st) h, there is a significant difference between the severity of nausea and vomiting in these two groups, but there is not a significant difference between 2 and 4 h after surgery. However, the incidence of nausea between the two groups shows a significant correlation.
CONCLUSIONS: A single dose of gabapentin 1 h before cesarean delivery decreases the incidence of nausea and vomiting after surgery.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Caesarean section is a surgical procedure in which incisions are made through a woman's abdomen and uterus for delivering her baby.[12] The worldwide statistics showed that about 10–30% of childbirths occurred by caesarean.[13] Therefore appropriate managing childbirth “anesthesia method and health of mother and fetus are important issues during caesarean section[4] which general and spinal anesthesia are common in cesarean.” In Sweden, 90% of caesarean sections are elective and 80% of emergency caesarian section performed by spinal anesthesia procedure.[5] By increasing caesarean sections via spinal anesthesia, the number of people affected by the undesired side effect of anesthesia such as nausea and vomiting was increased.[16] The prevalence of nausea and vomiting after surgery is about 20–30% and it is one of the concern to patient.[7] Different factors are involved in occurring nausea and vomiting after surgery by spinal anesthesia such as important factor vagal stimulation, sympathetic inhibition. The other factors such as systolic pressure loss <80 mm/mercury, block level more than the fifth thoracic segment, the addition of materials such as vascular retractor, neostigmine, and opioids to the anesthetic agent are the most common factors that increase the chance of nausea and vomiting. Hypotension leads into brainstem ischemia, which results into the stimulation of the vomiting center in the brain stem. In addition, hypotension is related to bowels ischemia and the release of nausea-causing substances such as serotonin. Totally, in regional anesthesia, a single mechanism is not the reason for nausea and vomiting and multiple mechanisms are involved in the same time.[8] The process of postoperative nausea and vomiting (PONV) have some side effects in common such as “pneumonia aspiration, dehydration, delay in discharge from the recovery room or hospital, electrolyte imbalance, increased postoperative hemorrhage, increased intracranial pressure.”[9] Other study also mentions that PONV could lead to increasing heart rate and systematic blood pressure and the risk of myocardial ischemia.[10] Gabapentin or Neurontin (commercially) is a structural analog of gamma amino butyric acid has multiple actions such as anticonvulsant, anti-nociceptive, and psychoactive.[11] Gabapentin are commonly used in various diseases such as chronic pain syndrome, reflex sympathetic dystrophy, and diabetic neuropathy.[12] It is also effective against a vast spectrum of pains such as neuropathy pain, neuralgia, and acute preoperative pains.[13] The results of a recent study showed that 300 mg gabapentin 1 h before surgery will decrease nausea and vomiting and 600 mg gabapentin could decrease in nausea and vomiting severity. Therefore, gabapentin administration is recommended in laparoscopic cholecystectomy for controlling the nausea and vomiting.[14] Moreover, other study revealed that gabapentin administration could decrease nausea and vomiting after abdominal hysterectomy and need to meperidine injection was reduced.[15] Therefore, in this study we attempt to use 600 mg gabapentin administration 1 h before caesarian surgery in order to decrease postoperative vomiting and nausea. The aim of this study was to evaluate the effects of gabapentin in preventing nausea and vomiting after spinal anesthesia in cesarean delivery.

PATIENTS AND METHODS

Study population

Between 2009 and 2010, a total of 200 patients who were candidates for cesarean section and referred to our hospital were assessed to enter the study. All eligible women requested for to provide an informed written consent. The study protocol was approved by Ethical Committee of the hospital.

The inclusion criteria were American Society of Anesthesiologists class 1 and 2, no cardiovascular, gastrointestinal middle ear, vertigo, motion diseases, diabetes, hypertension, smoking and alcohol consumption, no history of nausea and vomiting before the surgery and fever or the infection diseases. The candidate patients for this study have not been eating for about 6–8 h before surgery and the surgery must be done under the spinal anesthesia. Moreover, only cesarean must be done on them except the other surgery on them (before) and the duration of anesthesia and bleeding must not be unusually very high. In addition, the quantity of hemoglobin must not be <10 mg/day and they did not receive the other drugs except antibiotics and sedative medicines until 6 h after surgery. In this study, the numeric scale visual analog scale (VAS) was used as a visual tool in order to measure the severity of nausea (rank 0–10).

Study design and outcome assessment

For all patients, a combination of anesthesia and spinal anesthesia was used. At first, by the 1st researcher who was not involved in collecting data, gabapentin capsule, and placebo were given to the patients about 1 h before the surgery. By the 2nd researcher, the incidence of nausea, vomiting and their severity, according to the standard tool VAS during surgery and up to 4 h after surgery, were recorded in the recovery room and also in the related department in the page of information record. Data of cesarean candidates was collected by using a questionnaire that was not the part of the anesthesia team and not informed of the drug group assignment.

Statistical analysis

Results were given as mean ± standard deviation. Statistical analysis was performed using the SPSS software (Chicago, SPSS Inc) as well the descriptive statistics including dispersion and central measures and the statistical tests including t-test, Chi-square, and trend test were conducted.

RESULTS

The mean age of mothers and their neonates were 26.1 ± 5.1 years and 38.1 ± 0.48 months, respectively. The intended mothers are in these age ranges; 38% between 21 and 25 years, 35.5% between 26 and 30 years, 13% between 31 and 39 years, 12% (≤20 years), and 1.5% (more than 40 years) and in both groups, the separation of age groups were similar. In both groups, the highest age range is between 21 and 30 years and the lowest age range of participants in both groups is related to them others about 40 years or more. As a result, there is no significant difference in the age of mothers between two groups [Table 1].

Table 1

Baseline comparison between two study groups

The results showed that the severity of nausea between the two groups does not indicate significant relationship (P = 0.163), but in the 1st h (after the surgery), a significant difference was observed between these two groups due to the severity of nausea (P = 0.041). However, the incidence of vomiting between the two groups generally shows a significant difference (P = 0.048) [Tables 2 and 3].

Table 2

Frequency of vomiting incidence in two separate groups

Table 3

Frequency of nausea incidence in two separate groups

DISCUSSION

In the current study, after accomplishing the intervention means adding 600 mg gabapentin in order to treat patients prior to cesarean in the mothers undergoing spinal anesthesia, there was no statistically significant differences in the incidence of nausea in two groups namely group receiving gabapentin with the control groups (without receiving gabapentin) and it shows no significant effect of gabapentin in the prevention of postoperative nausea (of cesarean) during spinal anesthesia.

In this case, consumption of gabapentin in these two groups shows a significant difference in the severity of vomiting. More detailed findings of this study showed that using 600 mg of gabapentin reports a significant difference in the incidence of nausea and severity of vomiting in the 1st h of spinal anesthesia in spinal.

The same results were achieved by Ajori et al. They showed that gabapentin could decrease nausea, vomiting and pain postoperative abdominal hysterectomy. Their finding showed that the greatest impact of gabapentin is reducing the incidence of postoperative nausea whereas our results showed that gabapentin only controlled the incidence of nausea in the 1st h after spinal anesthesia.[15]

On the other hand, Misra et al. showed that in the patients undergoing craniotomy, gabapentin plus dexamethasone reduced the 24-h incidence of nausea and PONV. However, there was no reduction in either the postoperative pain scores or opioid consumption.[16] The findings of Khademi et al. also confirmed our findings. Their data showed that gabapentin reduced PONV after open cholecystectomy but also reduced the need for additional postoperative pethidine and metoclopramide administration.[17] In other study, Mohammadi and Seyedi showed that 300 mg gabapentin 1 h before laparoscopic surgery could decrease postoperative pain, analgesic requirement, and nausea.[18] However, due to the antiemetic effect of gabapentin in not well known and demonstrated, future studies suggested with larger sample size.

CONCLUSION

In general, conclusion based on the results of the current study, prescribing gabapentin results into the better control of nausea and vomiting as well the patient satisfaction and their recovery and it was observed that with a dose of 600 mg gabapentin, nausea, and vomiting could be controlled.