A risk score for predicting postoperative nauseas and Vomitings after inhalational agent comprises all except-
Most significant Risk factors which increases Post Operative Nausea Vomitting 1. Female gender 2. Prior history of motion sickness 3. Non smoking 4. Used for opioid postoperative FACTORS INFLUENCING POSTOPERATIVE NAUSEA AND VOMITING The etiology of emesis is multifactorial. The factors influencing the PONV are as follows: Patient factors Preoperative factors Intraoperative factors: Surgical factors Anesthesia factors Postoperative factors Patient factors Sex: Women are more likely to experience PONV compared to men. It is the strongest patient-specific predictor Motion sickness: Patients with history of motion sickness or vomiting after previous surgery are at increased risk for PONV Smoking: Nonsmokers are more prone for PONV. In smokers, gradual desensitization of CTZ occurs Age: Age <50 years is a significant risk factor for PONV Obesity: Recent data suggest that body mass index is not correlated with an increased risk for development of PONV Delayed gastric emptying: Patients with abdominal pathology, diabetes mellitus, hypothyroidism, pregnancy, increased intracranial tension, history of swallowing blood, and with full stomach are at increased risk of PONV. Preoperative factors Perioperative fasting: It is unceain as risk factor Anxiety: Clinically not relevant for PONV prediction. Intraoperative factors Surgical factors: Type of surgery: Cholecystectomy and gynecological and laparoscopic surgeries are associated with high incidence of PONV Duration of surgery: Longer duration surgeries are associated with increased incidence of PONV. Increasing operative duration by 30 min may increase the risk of PONV by 60%. Anesthesia factors: General anesthesia: * Nitrous oxide: Significant decrease in postoperative emesis was noted if nitrous oxide was avoided in patients undergoing laparoscopic procedures. Three mechanisms have been suggested as contributing factors to the increase in postoperative emesis associated with nitrous oxide 1. Stimulation of sympathetic nervous system with catecholamine release 2. Middle ear pressure changes resulting in traction of the membrane of round window and consequent stimulation of the vestibular system 3. Increased abdominal distension resulting from exchange of nitrous oxide and nitrogen in gas introduced into gastrointestinal tract during mask ventilation * Inhalational agents: Ether and cyclopropane cause a higher incidence of PONV due to increase in endogenous catecholamines. Sevoflurane, enflurane, desflurane, and halothane are associated with lesser degree of PONV. Effect of volatile anesthetics on PONV is dose-dependent and prominent in the first 2-6 h after surgery. Volatile anesthetics were the primary cause of early PONV (0-2 h after surgery); they did not have an impact on delayed PONV (2-24 h after surgery) * Etomidate: Continuous etomidate infusion as a pa of balanced anesthetic technique markedly increases the incidence of postoperative emesis * Ketamine: Studies have shown that ketamine used for induction resulted in delayed discharge, vivid dreams, hallucinations, and higher incidence of PONV compared to a patient receiving barbiturates with nitrous oxide. Emetic effect is secondary to endogenous catecholamine release * Propofol: It is popular for outpatient anesthesia due to its orable recovery characteristics including rapid emergence and reduced PONV * Balanced anesthesia: Compared to inhalational or total intravenous (IV) technique, the use of nitrous oxide-opioid-relaxant technique is associated with higher incidence of postoperative emesis. Emesis with balanced anesthesia has been attributed to use of an opioid-nitrous oxide combination, directly stimulating CTZ * Opioids: It causes emesis through stimulation of opioid receptors located in CTZ. The contribution of intraoperative opioids is weak; there is no difference among different opioids * Neuromuscular reversal agents: Incidence of PONV is unceain. Regional anesthesia: Risk for PONV was 9 times less among patients receiving regional anesthesia than those receiving general anesthesia.The incidence of postoperative emesis following regional nerve block procedures is usually lower than with general anesthesia. Emesis with central neuraxial block is greater than that with peripheral nerve block because of associated sympathetic nervous system blockade, which contributes to postural hypotension induced nausea and vomiting. The incidence of nausea after epidural opioid may be lower with more lipid soluble opioids such as fentanyl and sufentanil, which have less rostral spread from lumbar epidural injection site to CTZ and vomiting center, than the less lipid soluble opioids such as morphine. POSTOPERATIVE FACTORS Pain: Visceral or pelvic pain is a common cause of postoperative emesis Ambulation: Sudden motion, changes in position, transpo from the postanesthetic recovery unit to the postsurgical ward can precipitate nausea and vomiting in patients who have received opioid compounds Opioids: Postoperative opioids increase risk for PONV in a dose-dependent manner; this effect appears to last for as long as opioids are used for pain control in the postoperative period. Irrespective of route of administration, the incidence of nausea and vomiting appears to be similar. Nonsteroidal anti-inflammatory agents can be used in perioperative period to reduce opioid requirement Supplemental oxygen is no longer recommended for PONV prevention.
Female gender
Prior history of motion sickness
Non smoking
Obesity
Pre Anesthetic Evaluation