1Department of Anaesthesia, Christian Medical College and Hospital, Vellore 632 004, India and 2Department of Anaesthesia, North Staffordshire Hospital, Stoke-on-Trent, Staffordshire ST4 6QG, UK*Corresponding author
Accepted for publication: March 15, 2001
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() |
---|
Br J Anaesth 2001; 87: 5024
Keywords: vomiting, nausea, postoperative; analgesia, patient-controlled; vomiting, antiemetics, ondansetron; anaesthesia, obstetric
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() |
---|
The aim of our study was to evaluate whether administering prophylactic ondansetron along with morphine via PCA decreased PONV in obstetric patients and patient satisfaction.
![]() |
Methods and results |
---|
![]() ![]() ![]() ![]() ![]() ![]() |
---|
Women were randomly allocated into two groups by computer-generated random numbers in sequentially-numbered envelopes. Group P received a PCA with morphine (1 mg ml1), while Group O received ondansetron 4 mg intravenously at the end of surgery plus 8 mg added to the PCA morphine syringe (60 ml) (final ondansetron concentration 0.13 mg ml1). The PCA pump was programmed to deliver 1 ml per demand with a 3 min lockout and no background infusion. Prochlorperazine 12.5 mg i.m. was available as a rescue antiemetic to any patient who requested it.
The incidence and severity of pain, sedation, nausea and vomiting were assessed using four-point scales at 15 min intervals in the immediate recovery period and then 4 hourly until the PCA pump was discontinued. A midwife, unaware of the contents of the PCA syringe, made all postoperative assessments. Twenty-four hours later, one of the investigators assessed the patient for her perception regarding overall satisfaction with her care, control of nausea and vomiting and analgesia, using a scale of good, moderate or poor.
Data were analysed using the StatView® statistical package. Discrete variables were analysed using an unpaired t-test or non-parametric tests. Categorical variables were analysed using the chi squared or Fishers exact test, as appropriate. In all cases a P value of <0.05 was considered significant.
Patient characteristics between the two groups were similar except that the women in Group O were slightly heavier. There were no significant differences in the amount of morphine used, history of motion sickness, morning sickness, smoking, and PONV. The incidence of intraoperative hypotension and the requirement for an infusion of oxytocin to assist postoperative uterine contraction did not differ between the groups. There were no differences in the degree of pain between the two treatment groups at any time. Most patients were either pain-free or had only mild pain. All patients were awake or arousable to voice at all times.
The incidence of nausea and vomiting was significantly lower in the ondansetron group (Table 1). Twenty-three (57%) patients in Group P experienced severe nausea or vomiting compared with 10 (24%) in Group O (P<0.01). Eighteen women from Group P needed rescue antiemetic, compared with only five from Group O (P<0.01). Ondansetron was effective in reducing the incidence of PONV in those patients who had previously experienced morning sickness but not in those who had not (Table 1). There was no differential efficacy of ondansetron in patients with and without previous PONV, smoking or motion sickness, although the number of patients with these risk factors was relatively small. Six patients in Group P and two in Group O felt that the control of nausea and vomiting was poor, the difference was not significant. One patient in each group felt their overall care was unsatisfactory (Table 1).
|
![]() |
Comment |
---|
![]() ![]() ![]() ![]() ![]() ![]() |
---|
There are various factors that may contribute to PONV.10 The most important predictors are female gender, previous PONV, prolonged surgery, non-smoking, and motion sickness.10 We found that the incidence of PONV was higher among women who had significant morning sickness during early pregnancy. Ondansetron was beneficial in reducing PONV in these women, but appeared to make little difference in patients who did not experience significant morning sickness.
Prophylaxis of PONV is usually administered once or intermittently. There are a few studies where the antiemetic was added into the PCA syringe.16 Droperidol was used in most of these and was found to be effective, but caused increased sedation, a side effect that we felt was undesirable in the postpartum period. Postoperative sedation was rare in our patients and was not increased by the use of ondansetron. Alexander and colleagues showed that a bolus of ondansetron 4 mg plus 0.13 mg ml1 in the PCA syringe was effective in reducing PONV after orthopaedic surgery.2 This technique has not previously been investigated in postpartum patients.
When questioned about their perception of nausea and overall care, the responses of the two groups were similar, despite considerable differences in the incidence of PONV and request for rescue antiemetics. The high level of satisfaction could partly be a result of the euphoria of having a newborn baby and to the extra attention given by a sympathetic investigator who spent extra time with them. However, this should have applied equally to both groups.
Ondansetron is safe and effective, with a low incidence of adverse effects such as headache, dizziness, and increased liver enzymes. It has also been shown to be compatible with morphine sulphate.2 There are no reports of adverse effects of ondansetron in women who are breast feeding, although the manufacturer cautions against its use in this situation. However, similar advice applies to droperidol and prochlorperazine.
![]() |
Acknowledgement |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() |
---|
2 Alexander R, Lovell AT, Seingry D, Jones RM. Comparison of ondansetron and droperidol in reducing postoperative nausea and vomiting associated with patient-controlled analgesia. Anaesthesia 1995; 50: 10868[ISI][Medline]
3 Russell D, Duncan LA, Frame WT, Higgins SP, Asbury AJ, Millar K. Patient-controlled analgesia with morphine and droperidol following caesarean section under spinal anaesthesia. Acta Anaesthesiol Scand 1996; 40: 6005[ISI][Medline]
4 Williams OA, Clarke FL, Harris RW, Smith P, Peacock JE. Addition of droperidol to patient-controlled analgesia: effect on nausea and vomiting. Anaesthesia 1993; 48: 8814
5 Roberts CJ, Millar JM, Goat VA. The antiemetic effectiveness of droperidol during morphine patient-controlled analgesia. Anaesthesia 1995; 50: 55962[ISI][Medline]
6 Walder AD, Aitkenhead AR. A comparison of droperidol and cyclizine in the prevention of postoperative nausea and vomiting associated with patient-controlled analgesia. Anaesthesia 1995; 50: 6546[ISI][Medline]
7 Fisher DM. The big little problem of postoperative nausea and vomiting. Do we know the answer yet? (Editorial). Anesthesiology 1997; 87: 12713[ISI][Medline]
8 Fisher DM. Surrogate outcomes: meaningful not! (Editorial). Anesthesiology 1999; 90: 3556[ISI][Medline]
9 Scuderi PE, James RL, Harris L, Mims GR, III. Antiemetic prophylaxis does not improve outcomes after outpatient surgery when compared to symptomatic treatment. Anesthesiology 1999; 90: 36071[ISI][Medline]
10 Watcha MF, White PF. Postoperative nausea and vomiting. Its etiology, treatment, and prevention. Anesthesiology 1992; 77: 16284[ISI][Medline]