Postoperative Nausea and Vomiting An Overview
Khaled Harbey SayedAhmed;
Abstract
Postoperative nausea and vomiting (PONV) is one of the commonest and the most undesired complications of anesthesia and surgery. PONV has been identified as a surgical problem since 1848, shortly after the introduction of anesthesia.Despite the vast amount of research done in this field and the variety of antiemetic drugs available, PONV still has a high incidence. About 10% of surgical patients develop PONV in the postanesthesia care unit (PACU), and up to 30% of surgical patients develop PONV within the first 24 hours. PONV also poses dangers for ambulatory surgery patients, who may go home before symptoms develop. Postoperative nausea and vomiting encompasses three main symptoms (nausea, retching and vomiting) that may occur separately or in combination after surgery.
Emesis or vomiting is defined as the reflex action of ejecting the contents of the stomach through the mouth.Emesis can be divided into three phases; the pre-ejection phase whichis characterized by the symptom of nausea as well as the autonomic signs of increased salivation, swallowing, pallor, diaphoresis, and tachycardia. The ejection phase consists of retching and vomiting. The postejection phase consists of relaxation of respiratory and abdominal muscles and cessation of nausea.
Vomiting is controlled by a group of closely related nuclei in the brainstem termed the ‘vomiting centre’ that is rich in dopaminergic, histamine, 5‐ hydroxytryptamine, neurokinin and muscarinic cholinergic receptors. When the vomiting centre is stimulated, a complex series of neural impulses co-ordinates the simultaneous relaxation of the gastric muscles and contraction of the abdominal muscles and diaphragm, expelling vomitus from the stomach. Nausea, often the precursor to vomiting, is triggered by a low level of the same stimuli responsible for the vomiting reflex but the exact mechanism underlying the sensation of nausea isunclear. It is often accompanied by salivation, sweating and pallor.
PONV can result in morbidity like wound dehiscence, bleeding, pulmonary aspiration, fluid and electrolyte disturbances, delayed hospital discharge, unexpected hospital admission, and decreased patient satisfaction.
Not all surgical patients will experience PONV or experience it to the same degree. Understanding and identifying risk factors can help clinicians decide whether the patient should receive prophylaxis or later treatment for PONV. Causes of PONV include the patient and his or her associated risk factors, the underlying disease process that prompted the surgery, the type of surgery, and the anesthetic technique.Emetic risk profiles of every patient can be established during the preoperative anesthetic visit. Although the underlying baseline risk of PONV remains unpredictable, patients who are at high risk of suffering fromPONVcan still be identified.
Routine antiemetic prophylaxis is not required in all patients. However, antiemetic prophylaxis will undeniably improve patient satisfaction in high risk groups. Prophylactic ant-iemetic monotherapy is no longer acceptable because of poor efficacy. None of the drugs tested can be considered “gold standard” and none is good enough to be used on its own.Instead, a multimodal stratagies comprising the use of anxiolytic premedication, avoidance of emetogenic anesthetic techniques, combination pharmacological anti-emetic therapy, nonpharmacologic therapy, adequate IV hydration, avoidance of hypotension, adequate pain relief and gentle transfer of patient from operating room to recovery area should be adopted.The anti-emetics comprise variable classes of drugs,each one has its own mode of action ,benefits and side effects.
When nausea and vomiting occur postoperatively, treatment should be administered with an anti-emetic from a pharmacologic class that is different from the prophylactic drug initially given, or if no prophylaxis was given, the recommended treatment is a low-dose 5-HT3 antagonist. The 5-HT3 antagonists are the only drugs that have been adequately studied for the treatment of existing PONV. The doses of 5-HT3 antagonists used for treatment are smaller than those used for prophylaxis.Alternative treatments for established PONV include dexamethasone, droperidol and/or promethazine. Propofol;as needed,can be considered for rescue therapy in patients still in the PACU and is as effective as ondansetron, a5-HT3 antagonist. However, the anti-emetic effect with low doses of propofol is probably brief.
Emesis or vomiting is defined as the reflex action of ejecting the contents of the stomach through the mouth.Emesis can be divided into three phases; the pre-ejection phase whichis characterized by the symptom of nausea as well as the autonomic signs of increased salivation, swallowing, pallor, diaphoresis, and tachycardia. The ejection phase consists of retching and vomiting. The postejection phase consists of relaxation of respiratory and abdominal muscles and cessation of nausea.
Vomiting is controlled by a group of closely related nuclei in the brainstem termed the ‘vomiting centre’ that is rich in dopaminergic, histamine, 5‐ hydroxytryptamine, neurokinin and muscarinic cholinergic receptors. When the vomiting centre is stimulated, a complex series of neural impulses co-ordinates the simultaneous relaxation of the gastric muscles and contraction of the abdominal muscles and diaphragm, expelling vomitus from the stomach. Nausea, often the precursor to vomiting, is triggered by a low level of the same stimuli responsible for the vomiting reflex but the exact mechanism underlying the sensation of nausea isunclear. It is often accompanied by salivation, sweating and pallor.
PONV can result in morbidity like wound dehiscence, bleeding, pulmonary aspiration, fluid and electrolyte disturbances, delayed hospital discharge, unexpected hospital admission, and decreased patient satisfaction.
Not all surgical patients will experience PONV or experience it to the same degree. Understanding and identifying risk factors can help clinicians decide whether the patient should receive prophylaxis or later treatment for PONV. Causes of PONV include the patient and his or her associated risk factors, the underlying disease process that prompted the surgery, the type of surgery, and the anesthetic technique.Emetic risk profiles of every patient can be established during the preoperative anesthetic visit. Although the underlying baseline risk of PONV remains unpredictable, patients who are at high risk of suffering fromPONVcan still be identified.
Routine antiemetic prophylaxis is not required in all patients. However, antiemetic prophylaxis will undeniably improve patient satisfaction in high risk groups. Prophylactic ant-iemetic monotherapy is no longer acceptable because of poor efficacy. None of the drugs tested can be considered “gold standard” and none is good enough to be used on its own.Instead, a multimodal stratagies comprising the use of anxiolytic premedication, avoidance of emetogenic anesthetic techniques, combination pharmacological anti-emetic therapy, nonpharmacologic therapy, adequate IV hydration, avoidance of hypotension, adequate pain relief and gentle transfer of patient from operating room to recovery area should be adopted.The anti-emetics comprise variable classes of drugs,each one has its own mode of action ,benefits and side effects.
When nausea and vomiting occur postoperatively, treatment should be administered with an anti-emetic from a pharmacologic class that is different from the prophylactic drug initially given, or if no prophylaxis was given, the recommended treatment is a low-dose 5-HT3 antagonist. The 5-HT3 antagonists are the only drugs that have been adequately studied for the treatment of existing PONV. The doses of 5-HT3 antagonists used for treatment are smaller than those used for prophylaxis.Alternative treatments for established PONV include dexamethasone, droperidol and/or promethazine. Propofol;as needed,can be considered for rescue therapy in patients still in the PACU and is as effective as ondansetron, a5-HT3 antagonist. However, the anti-emetic effect with low doses of propofol is probably brief.
Other data
| Title | Postoperative Nausea and Vomiting An Overview | Other Titles | قيئ وغثيان ما بعد العمليات الجراحية مراجعة شاملة | Authors | Khaled Harbey SayedAhmed | Issue Date | 2015 |
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