Low-Dose Drop&do1 versus Standard-Dose-Droperidol for Prevention of Postoperative Vomiting after Pediatric Strabismus Surgery Raeford E. Brown, Jr., MD,* Daniel J. James, MD,* R.Grey Weaver, MD,?’Randall D. Wilhoit, MD,* Loren A. Bauman, MD* Departments of Anesthesia and Ophthalmology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC.

J. Clin. Anesth. 3:306-309,

1991

*Assistant Professor of Anesthesia tAssistant Professor of Ophthalmology Address reprint requests to Dr. Brown at the Department of Anesthesia, Bowman Gray School of Medicine, 300 Hawthorne Road, Winston-Salem, NC 27103, USA.

Study Objective: To determine whether a low dose of droperidol is as effective as a high dose in preventing vomiting after pediatric strabismus surgery. Design: Randomized, double-blind study. Setting: Operating room and recovery room at a university medical center. Patients: One hundred children undergoing strabismusprocedures. Interventions: Patients were divided randomly into three groups and received either droperidol 75 pglkg, droperidol20 kg/kg, or saline. Measurements and Main Results: Vomiting was assessed in all groups, as was time to discharge and ability to perform a satisfactorypostoperative eye examination. Children who received droperidol vomited less frequently than those who did not (p = 0.0521). There was no diff erence in the frequency of vomiting between the two groups that received droperidol. Conclusions: Droperidol 20 pglkg is as effective as droperidol 75 kglkg in preventing vomiting after pediatric strabkmus surgery. Because higher doses of droperidol may sedate some patients, the lowest effective dose should be wed. In this study, however, there was no statisticallysignificant difference with regard to length of recovery room stay. Keywords: Droperidol;

vomiting; strabismus; anesthesia;

pediatrics.

Received for publication May 8, 1990; revised manuscript accepted for publication November 16, 1990.

Introduction

0 1991 Butterworth-Heinemann

Pediatric strabismus repair, a common outpatient surgical procedure, is frequently complicated by postoperative nausea and vomiting with a re-

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Low-dose droperidol: Brown et al.

ported frequency of 30% to SO%.1-5 This complication occurs regardless of anesthetic technique. Vomiting after surgery, if persistent, may upset electrolyte balance, cause dehydration, and prolong hospitalization. Droperidol, a butyrophenone, has been shown to reduce vomiting dramatically after strabismus sdrgery. Studies have suggested that 75 pg/kg is required for adequate antiemetic action.3 In our experience, this dose sedates children and makes postoperative ophthalmological evaluation difficult. Lower doses of droperidol are routine in adults and have been shown to be effective in some pediatric patients.‘j A higher dose of droperidol (75 kg/kg) was compared with a lower dose (20 pg/kg) to evaluate the efficacy of the lower dose in preventing nausea and vomiting after strabismus surgery. We also evaluated differences in length of recovery associated with these two regimens, as well as problems with the postoperative strabismus evaluation.

Materials and Methods The study was approved by the Bowman Gray School of Medicine Clinical Research Practices Committee. One hundred ASA physical status I and II children, ages 2 to 18, were studied after informed consent was obtained from parents for this randomized, doubleblind study. Patients with superimposed medical disease or with medical problems predisposing to nausea and vomiting were excluded. One child was premedicated with rectal methohexital sodium. Anesthesia was induced by mask halothane (n = 97) or intravenous (IV) thiopental sodium (n = 3). The dose of thiopental sodium used for induction was 4 mg/kg. All anesthetics were maintained with halothane (1% to 1.5%), nitrous oxide (N,O) (70%), and oxygen (0,) (30%). Muscle paralysis was obtained with pancuronium. The preoperative fluid deficit was completely replaced in all patients before discharge from the postanesthesia care unit (PACU). The fluid deficit was calculated by multiplying the number of hours the child fasted by the calculated hourly maintenance fluid requirement. The stomach was decompressed with an oral/gastric catheter prior to extubation. Droperidol 75 &kg (n = 33), droperidol20 Kg/kg (n = 34), or saline (n = 33) was injected IV in a double-blind fashion just after the induction of anesthesia in each case. Vomiting was assessed by blinded nursing staff in the PACU and the ambulatory surgery center. A prolonged PACU stay was defined as more than 1 hour. Ease of examination was evaluated by the attending ophthalmologist in his office after the patient was dis-

charged. The eye evaluation included an attempt to assess fixation in young children, visual acuity in older children, measurement of strabismus at a distance and close up, and ocular versions. Most of the eye examinations were performed in the eye clinic after discharge from ambulatory surgery. For patients with prolonged sedation (more than 2 hours in the ambulatory surgery center), the eye examination was performed on the first postoperative day. Anesthetics were administered by one of three pediatric anesthesiologists. All ocular examinations were performed by a single pediatric ophthalmologist. The eye examination was considered satisfactory if the patient was awake enough to be capable of cooperating with the assessment. Descriptive statistics are shown in Table 1. Values for all associations of droperidol dosage data are shown in Table 2.

Results No statistical differences existed among the three groups with regard to age, weight, or preoperative fluid deficit. Vomiting occurred in 39 patients. Eighteen of those patients were in the saline control group, with the other 21 evenly divided between the droperidol 75 Kg/kg and the droperidol 20 pg/kg groups. The frequency of an unsatisfactory examination was the same in all groups, as was the frequency of a discharge delay Table 1. Low-Dose Droperidol versus Standard-Dose Droperidol (percent) Event

Droperidol ‘5 l&Q

Droperidol 20 pg/kg

Saline

30 12 18

34 7 16

53* 9 12

Vomiting Prolonged PACU stay Unsatisfactory eye exam

_

PACU = postanesthesia care unit. *Different from both droperidol exact test.

groups Cp = 0.0521)

by Fischer’s

Table 2. Low-Dose Droperidol versus Standard-Dose Droperidol p-value Droperidol

Droperidol Droperidol Droperidol

J.

75 75 20 75

pg/kg p.g/ka $/kg pg/kg

us droperidol 20 kg/kg vs saline us saline and 20 pg/kg us saline

Clin. Anesth.,

vol. 3, July/August

0.7928 0.0837 0.14553 0.0521

1991

307

greater than 1 hour in the PACU. The time from the end of surgery to arrival in the PACU was virtually the same in all groups. There was a tendency for a prolonged recovery room stay in children receiving droperidol 75 kg/kg, but this tendency was not statistically significant (PACU stay: droperidol 75 pg/kg average 39 minutes, droperidol 20 kg/kg average 32 minutes, saline control average 32 minutes). Modest clinical significance was attained in the analysis of vomiting (p = 0.052). The results suggest a beneficial clinical effect in both the high- and lowdose droperidol groups. Twenty-five patients were contacted by telephone on the first postoperative day to evaluate the presence or absence of vomiting after discharge. Only one child who had not vomited before discharge did so afterward. No patients in this study were readmitted for persistent vomiting.

Discussion The efficacy of droperidol in preventing vomiting after strabismus surgery has been studied repeatedly. Abramowitz et al3 found a droperidol dose of 75 pgl kg effective in reducing the frequency of vomiting to 43%. Eighty percent of patients in their control group vomited. Lerman et al.? demonstrated a reduction in vomiting to 16% after administration of a similar dose but prior to eye muscle manipulation. In the present study, less than 55% of patients vomited regardless of treatment. Those patients treated with droperidol vomited less than 35% of the time; there were no differences between standard-dose and low-dose droperidol groups in the frequency of vomiting. The overall frequency of post-strabismus surgery vomiting was low and may reflect conservative clinical management techniques, such as suctioning the stomach at the end of the procedure, complete replacement of the preoperative deficit in the operating room and PACU, no use of opioids preoperatively or intraoperatively, and not requiring oral intake as a discharge criterion from the ambulatory surgery center. It has been suggested that replacement of preoperative fluid deficits may have a salutary effect on postoperative outcome.8 An unsatisfactory examination by the attending ophthalmologist was as likely in the control group as in either of the droperidol groups. There was, however, a tendency for the patient to be drowsier than normal if any droperidol had been given. There was no indication that either dose of droperidol prolonged discharge from the recovery room or the ambulatory surgery center. There was, how308

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ever, a tendency for a longer PACU stay for droM.siness observed m children who received droperidol 75 pg/kg. This finding was offset, however, by children who were nauseated, vomiting, or drowsy for other reasons. Droperidol, a central nervous system depressant, is very effective in reducing vomiting in most models, even at low doses. Side effects of droperidol have been reported”.‘(’ and are quite common at doses of 100 pg/kg and greater. Although others have reported effectiveness only at higher doses,” we have used a low dose for many years with excellent results. This study was designed on the basis of our own experience and that of our colleagues. For these reasons, we feel that the management of children during and after strabismus surgery should include intraoperative suctioning of gastric contents, replacement of preoperative fluid deficits, and the avoidance of opioids. In addition, we believe that a small dose of droperidol (20 pg/kg) is a reasonable addition to the care of these patients and will reduce the likelihood of postoperative vomiting.

Acknowledgment The editorial acknowledged.

assistance

of Faith

McLellan

is gratefully

References 1. Wunsh SE: Ambulatory pediatric ophthalmic surgery. J Pediatr Ophthalmol Strabismus 1979; 16:398--g. MD, Elder PT, Friendly DS, Broughton 2. Abramowitz WL, Epstein BS: Antiemetic effectiveness of intraoperatively administered droperidol in pediatric strabismus outpatient surgery-preliminary report of a controlled study. J Pediatr Ophthalmol Strabismus 198 1; 18:22-7. 3. Abramowitz MD, Oh TH, Epstein BS, Ruttimann UE, Friendly DS: The antiemetic effect of droperidol following outpatient strabismus surgery in children. Anesthesiology 1983;59:579-83. 4. Hadaway EG, Ingram RM, Traynar MJ: Day case surgery for strabismus in children. Tranr Ophthulmol Sot UK 1977;97:23-5. 5. Rowley MP, Brown TC: Postoperative vomiting in children. Anaesth Intensive Care 1982; 10:309-13. 6. Rita L, Goodarzi M, Seleny F: Effect of low dose droperidol on postoperative vomiting in children. Can Anaesth Sot J 1981;28:259-62. 7. Lerman J, Eustis S, Smith DR: Effect of droperidol pretreatment on post-anesthetic vomiting in children undergoing strabismus surgery. Anesthesiology 1986; 65: 322-5.

Low-dose droperidol: Brown et al.

8. Keane

PW, Murray PF: Intravenous fluids in minor surgery. Their effect on recovery from anaesthesia. Anaesthesia 1986;41:635-7. D, Phitayakorn P, 9. Melnick B, Sawyer R, Karambelkar Lim Uy NT, Pate1 R: Delayed side effects of droperidol Anesth Analg after ambulatory general anesthesia. 1989;69:748-51.

COURS

10. Melnick

BM: Extrapyramidal

reaction

to low-dose dro-

peridol. Anesthesiology 1988;69:424-6. pre11. Eustis S, Lerman J, Smith D: Effect of droperidol treatment on post-anesthetic vomiting in children undergoing strabismus surgery: the minimum effective dose. J Pediatr Ophthalmol Strabismus 1987;24: 165-8.

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Title page of M. Claude Bernard’s 1875 Lecons SW Les Anesfhetiques et SW L’Asphyxie. From Fink BR (Trans.): Studies on Anesthetics and on Asphyxia, by Claude Bernard. Park Ridge, IL: Wood Library-Museum of Anesthesiology, 404 pp.

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1991

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Low-dose droperidol versus standard-dose droperidol for prevention of postoperative vomiting after pediatric strabismus surgery.

To determine whether a low dose of droperidol is as effective as a high dose in preventing vomiting after pediatric strabismus surgery...
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