[Risk factors and frequency of postoperative nausea and vomiting in patients operated under general anesthesia]

Abstract

Introduction: Postoperative nausea and vomiting belong to fairly frequent postoperative complications, but they occupy a distant position on the list of complications, which most probably result from a general conviction that they do not pose a direct threat to patients.

Objective: The objective of this work is specification of factors facilitating occurrence of postoperative nausea and vomiting, and determination of frequency of their occurrence in patients operated under general anesthesia.

Material and methods: Questionnaire about the occurrence of postoperative nausea and vomiting (PONV), was carried out and included 253 adult sick persons (102 female and 151 male patients), in the age between 23-76 (average 42.3 +/- 6.1 years), who had undergone operative procedure in the field of abdominal and urology surgery, orthopedic, thyroid surgery and laryngological, ophthalmology and plastic surgery, under general anesthesia. The questionnaire form included preoperative characteristics of a patient (age, sex, smoking, motion sickness and migraine headaches in history, and PONV occurring earlier), type of operative procedure, used anesthetic agents, and analgesic agents applied in postoperative analgesia. The anesthesiologist administering anesthetic was not informed about the investigation carried out and did not receive any additional pieces of advice regarding the type of applied anesthetic agents or the method of conducting postoperative analgesia. Visual Analogue Scale (VAS) was used in the evaluation of nausea. Nausea and vomiting were assessed every two hours within the first postoperative 12 hours and every 4 hours for the next 24 hours. Nausea and vomiting were treated as two separate complications.

Results: Nausea itself occurred in 22.7% of patients; whereas vomiting in 13.2%. Both symptoms occurred in 14.2% of patients. Nausea occurred 4.1 +/- 0.8 hours after operation; whereas vomiting after 5.3 +/- 1.1 hours. Women suffered more often than men from (R = 0.678 p < 0.001). The same was registered for non-smokers (nausea: R = 0.623, vomiting: R = 0.437), and for the patients suffering from PONV earlier (R = 0.421 for nausea, and R=0.331 for vomiting). PONV also occurred more often in cases of obese patients (p < 0.002) and the patients anesthetized by younger anesthetists (p < 0.002). Clear relation between the frequency of postoperative nausea and vomiting occurrence and the type of operative procedure was also noticed. The relation appeared to be the strongest (R = 0.531; p < 0.001) in case of the sick who underwent abdominal and laryngological procedures (R= 0.421; p < 0.02), as well as ophthalmologic (R= 0.407; p < 0.02) procedures. However, the relation was the weakest in case of the sick who underwent orthopedic procedures (R =0.127; p < 0.02). The correlation between anesthesia induction agents and frequency of PONV was not observed. PONV was significantly more frequent in case of the sick receiving postoperative opioids than those who received nonsteroid anti-inflammatory drugs.

Conclusions: (1) PONV is more frequent in women than in men. The same refers to non-smokers, suffering from migraine headaches, motion sickness, as well as obesity and suffering from PONV earlier. (2) The frequency of postoperative vomiting in the patients with nausea is higher by 65.2% than in the patients without nausea. (3) A clear relation between the frequency of postoperative nausea and vomiting occurrence and the type of operative procedure was noticed. It was the strongest in the sick who underwent orthopedic procedures. (4) The correlation between anesthesia induction agents and PONV was not observed.