Postoperative nausea and vomiting
Encyclopedia
Postoperative nausea and vomiting (PONV) is an unpleasant complication affecting about a third of the 10% of the population undergoing general anaesthesia
each year. This equates to about two million people in the United Kingdom annually.
is especially effective by itself, and successful control is often elusive, experts recommend a multimodal approach. Anaesthetic strategies to prevent vomiting include using regional anaesthesia
wherever possible and avoiding emetogenic drugs. Pharmacological treatment and prevention of postoperative nausea and vomiting is limited by both cost and the adverse effects of drugs. Patients with risk factors probably warrant prophylaxis, whereas a "wait and see" strategy is appropriate for those without risk factors.
In conjunction with antiemetic medications, at least one study has found that application to the Pericardium Meridian 6 accupressure point produced a positive effect in relieving postoperative nausea and vomiting. Another study found no statistically significant difference.
3 receptor antagonist, ondansetron
, in the early 1990s was a significant breakthrough. Despite the many studies, however, the evidence base to support rational antiemetic treatment remains patchy. Recent research has led to better understanding of some older drugs and has demonstrated that combinations of drugs are often useful. While the efficacy of droperidol
is now clear, metoclopramide
, a popular antiemetic for decades, was found to have limited efficacy at the lower traditional dosage. Some older drugs, such as haloperidol
and hyoscine remain inadequately studied.
Emetogenic drugs commonly used in anaesthesia include nitrous oxide
, physostigmine
and opioids. The intravenous anaesthetic propofol
is currently the least emetogenic general anaesthetic
.
, and patients factors. Gynaecological, urological, strabismus correction and middle ear surgery all have a higher risk of postoperative nausea and vomiting.
Patients that are female or who have a history of postoperative nausea and vomiting are at greater risk. Smokers
have a decreased risk, but this would never be recommended by any physician. Older patients suffer less PONV.
General anaesthesia
General anaesthesia is a state of unconsciousness and loss of protective reflexes resulting from the administration of one or more general anaesthetic agents...
each year. This equates to about two million people in the United Kingdom annually.
Impact
On average the incidence of nausea or vomiting after general anesthesia ranges between 25 and 30% [Cohen 1994]. Nausea and vomiting can be extremely distressing for patients and is therefore one of their major concerns [Macario 1999]. Vomiting has been associated with major complications such as pulmonary aspiration of gastric content and might endanger surgical outcomes after certain procedures, for example after maxillofacial surgery with wired jaws. Nausea and vomiting can delay discharge and about 1% of patients scheduled for day surgery require unanticipated overnight admission because of uncontrolled postoperative nausea and vomiting.Management
Because no currently available antiemeticAntiemetic
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer....
is especially effective by itself, and successful control is often elusive, experts recommend a multimodal approach. Anaesthetic strategies to prevent vomiting include using regional anaesthesia
Regional anaesthesia
Regional anaesthesia is anaesthesia affecting only a large part of the body, such as a limb or the lower half of the body. Regional anaesthetic techniques can be divided into central and peripheral techniques. The central techniques include so called neuraxial blocks...
wherever possible and avoiding emetogenic drugs. Pharmacological treatment and prevention of postoperative nausea and vomiting is limited by both cost and the adverse effects of drugs. Patients with risk factors probably warrant prophylaxis, whereas a "wait and see" strategy is appropriate for those without risk factors.
In conjunction with antiemetic medications, at least one study has found that application to the Pericardium Meridian 6 accupressure point produced a positive effect in relieving postoperative nausea and vomiting. Another study found no statistically significant difference.
Pharmacology
The introduction of the 5HTSerotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...
3 receptor antagonist, ondansetron
Ondansetron
Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic , often following chemotherapy. Its effects are thought to be on both peripheral and central nerves...
, in the early 1990s was a significant breakthrough. Despite the many studies, however, the evidence base to support rational antiemetic treatment remains patchy. Recent research has led to better understanding of some older drugs and has demonstrated that combinations of drugs are often useful. While the efficacy of droperidol
Droperidol
Droperidol is an antidopaminergic drug used as an antiemetic and antipsychotic...
is now clear, metoclopramide
Metoclopramide
Metoclopramide is an antiemetic and gastroprokinetic agent. It is commonly used to treat nausea and vomiting, to facilitate gastric emptying in people with gastroparesis, and as a treatment for the gastric stasis often associated with migraine headaches.-Medical uses:Metoclopramide is commonly...
, a popular antiemetic for decades, was found to have limited efficacy at the lower traditional dosage. Some older drugs, such as haloperidol
Haloperidol
Haloperidol is a typical antipsychotic. It is in the butyrophenone class of antipsychotic medications and has pharmacological effects similar to the phenothiazines....
and hyoscine remain inadequately studied.
Emetogenic drugs commonly used in anaesthesia include nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...
, physostigmine
Physostigmine
Physostigmine is a parasympathomimetic alkaloid, specifically, a reversible cholinesterase inhibitor. It occurs naturally in the Calabar bean....
and opioids. The intravenous anaesthetic propofol
Propofol
Propofol is a short-acting, intravenously administered hypnotic agent. Its uses include the induction and maintenance of general anesthesia, sedation for mechanically ventilated adults, and procedural sedation. Propofol is also commonly used in veterinary medicine...
is currently the least emetogenic general anaesthetic
General anaesthetic
A general anaesthetic is a drug that brings about a reversible loss of consciousness. These drugs are generally administered by an anaesthesia provider to induce or maintain general anaesthesia to facilitate surgery...
.
Risk factors
Postoperative nausea and vomiting results from anaesthesic, surgicalSurgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, and patients factors. Gynaecological, urological, strabismus correction and middle ear surgery all have a higher risk of postoperative nausea and vomiting.
Patients that are female or who have a history of postoperative nausea and vomiting are at greater risk. Smokers
Tobacco smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...
have a decreased risk, but this would never be recommended by any physician. Older patients suffer less PONV.