Perioperative gastric aspiration increases postoperative nausea and vomiting in outpatients

Claude A. Trtpanier MDFRCPC,Liette Isabel MDFRCPC The efficacy o f aspiration o f gastric contents to reduce postoperative nausea and vomiting was investigated in a controlled randomized, double-blind study o f 265 outpatients. Patients in the treated group had their stomachs aspirated with an orogastric tube. In the control group no tube was inserted. Data on the incidence o f nausea and vomiting were collected in the recovery room, the day surgery unit and the day after surgery. The overall incidence o f postoperative nausea and vomiting was comparable in the two groups. It was also comparable in the recovery room and the day surgery unit. However, treated patients had a higher incidence o f both nausea (26.5% vs 12.0o/o, P < 0.005) and vomiting (16.7% vs 6.8%, P < 0.02) after their discharge from the day surgery unit. We conclude that aspiration o f gastric contents with an orogastric tube does not decrease postoperative nausea and vomiting in outpatients and may increase it after discharge o f the patient. L'efficacit~ de l'aspiration du contenu gastrique dans le but de rdduire l~ncidence des naus~es et des vomissements postopdratoires a ~t~ ~valu~e au cours d'une ~tude contr61~e randomis~e gl double insu chez 265 patients dans un centre de chirurgie d'un jour. L'estomac des patients du groupe trait~ a ~t~ aspir~ avec une sonde gastrique alors que dans le groupe t~moin on n'a pas insdr~ de sonde. Les donn.~es concernant l'incidence des naus~es et des vomissements ont ~td recueillies la salle de r~veil, h l'unit~ de chirurgie d'un jour et le lendemain de la chirurgie. L'incidenee totale des naus~es et vo- - From the Dtpartement d'Anesthtsie, H6pital de l'Enfant-Jtsus Universit6 Laval, 1401, 18e rue, Qutbec. Address correspondence to: Dr Claude Trtpanier, Htpital de l'Enfant-Jtsus, 1401, 18e rue, Qutbec, GIJ 1Z4. Presented at the Canadian Anaesthetists'Societymeeting, Quebec, Canada, June 1991. Acceptedfor publication l l th December, 1992. Perioperative gastric aspiration increases postoperative nausea and vomiting in outpatients missements f u t comparable dans les deux groupes. II n'y a pas eu non plus de diffdrence d la salle de r~veil et h l'unit~ de chirurgie d'un jour. Cependant, les patients trait~s ont pr~sent~ une incidence plus ~levde de naus~es (26,5% vs 12,0%, P < 0,005) et vomissements (16,7% vs 6,89'o P < 0,02) aprbs leur d~part de l'unitd de chirurgie d'rm jour. Nous concluons que l'aspiration du contenu gastrique ne diminue pas l~ncidence des naus~es et vomissements postopdratoires chez les patients de chirurgie d'un jour. En r~alit~, cette manoeuvre semble augmenter l~ncidence de cette complication aprbs le d~part de l'unit~ chirurgicale. Nausea and vomiting are two of the most frequent and troublesome complications of general anaesthesia. Despite improvement of anaesthetic techniques and the availability of new agents, the reported incidence of nausea and vomiting remains around 30%. 1,2 This complication is particularly annoying in the outpatient setting where the patient is expected to recover autonomy rapidly. Two studies reported that vomiting was the most frequent anaesthetic complication resulting in an unexpected hospital stay after outpatient surgery. 3,4 Many attempts have been made to prevent postoperative nausea and vomiting. One of them is to empty the stomach with a gastric tube. Although it has been recommended in review articles, 1,5 most data on this topic comes from older retrospective studies. 6-9 No study has investigated the effectiveness of this manoeuvre to reduce postoperative nausea and vomiting in outpatients. The purpose of this study was to investigate the effect of gastric emptying with an orogastric tube on the incidence of nausea and vomiting after general anaesthesia in outpatients. Method Two hundred and sixty-five ASA I, II and III patients scheduled to undergo day surgery requiting general anaesthesia were studied prospectively. Patients with upper digestive tract pathology or taking antiemetic drugs were excluded. Those scheduled for a laparoscopy were 0.88 + 0.36 0.92+ 0.38 125 -t-55 125  50 also excluded because it was considered unethical not to decompress the stomach prior to abdominal puncture. The protocol was approved by the hospital ethics committee and an informed, written consent was obtained from all patients. Patients were fasted from midnight and were not given any premedication. Anaesthesia was induced with fentanyl 2 ~g. kg -~ and thiopentone 3-5 rag. kg-[ Succinylcholine 1.5 m g . kg -I preceded by dtubocurarine 0.05 m g . kg -I was given to facilitate tracheal intubation. The lungs were ventilated by mask until complete relaxation was obtained while avoiding excessive positive airway pressure and the trachea was intubated when complete relaxation was obtained. If, during mask ventilation, the high airway pressure alarm, which was set at 25 cm H20, was activated, the patient was excluded from the study. Ventilation was controlled with an Ohmeda 7810 ventilator and a circle circuit. Minute ventilation was adjusted to maintain a normal end-tidal PCO2. Patients were then divided into two groups by random allocation. In Group 1, the study group, an orogastric tube was inserted and the stomach contents were aspirated. In Group 2, the control group, no gastric tube was inserted. Anaesthesia was maintained with 60% nitrous oxide in oxygen, isoflurane and supplemental doses of fentanyl, up to 5 ~tg- kg-L At the end of surgery, in the patients of the study group, the gastric tube was aspirated again and then removed and, in all patients, the trachea was extubated. Patients were then taken to the recovery room where data on the occurrence of nausea, retching or vomiting were collected. Data were collected by a nurse who was unaware of the purpose of the study and of the patient's group. Vomiting was defmed as the forceful expulsion of even a small amount of gastric content through the mouth, retching as expulsive efforts not leading to the expulsion of any material and nausea as the subjective sensation of the desire to vomit. For data analysis, patients presenting with retching were considered to have vomited. The same data were also collected at the day surgery unit and 24 hr postoperatively by telephone, also in a double-blind manner. Sample size was calculated considering a treatment effect of 50% as minimal relevant difference, 0.I0 as the upper limit for type II error and an incidence of 35% of nausea and vomiting as determined by a pilot study. Statistical analysis was done using the Chi square test with Yates correction and the Student's t test, relative risks with 95% confidence interval are also reported. A P value < 0.05 was considered significant. Results are presented as mean + SD. Mean + SD (or numbers). No differencebetweenthe two groupsfor any variable. patients were excluded because they could not be reached by phone for postoperative data collection, six in the control group a (...truncated)