History of migraine, history of PONV or motion sickness in a child's parent or sibling, better ASA physical status, intense preoperative anxiety, certain ethnicities or surgery types, decreased perioperative fluids, crystalloid versus colloid administration
Vomiting (also known as emesis and throwing up)[a] is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenteritis, pregnancy, motion sickness, or hangover; or it can be an after effect of diseases such as brain tumors, elevated intracranial pressure, or overexposure to ionizing radiation. The feeling that one is about to vomit is called nausea; it often precedes, but does not always lead to vomiting. Impairment due to alcohol or anesthesia can cause inhalation of vomit, leading to suffocation. In severe cases, where dehydration develops, intravenous fluid may be required. Antiemetics are sometimes necessary to suppress nausea and vomiting. Self-induced vomiting can be a component of an eating disorder such as bulimia, and is itself now classified as an eating disorder on its own, purging disorder.
Prolonged and excessive vomiting depletes the body of water (dehydration), and may alter the electrolyte status. Gastric vomiting leads to the loss of acid (protons) and chloride directly. Combined with the resulting alkaline tide, this leads to hypochloremicmetabolic alkalosis (low chloride levels together with high HCO− 3 and CO 2 and increased blood pH) and often hypokalemia (potassium depletion). The hypokalemia is an indirect result of the kidney compensating for the loss of acid. With the loss of intake of food the individual may eventually become cachectic. A less frequent occurrence results from a vomiting of intestinal contents, including bile acids and HCO− 3, which can cause metabolic acidosis.
Repeated or profuse vomiting may cause erosions to the esophagus or small tears in the esophageal mucosa (Mallory–Weiss tear). This may become apparent if fresh red blood is mixed with vomit after several episodes.
Vomiting also initiates an SNS response causing both sweating and increased heart rate.
The vomiting act has two phases. In the retching phase, the abdominal muscles undergo a few rounds of coordinated contractions together with the diaphragm and the muscles used in respiratory inspiration. For this reason, an individual may confuse this phase with an episode of violent hiccups. In this retching phase, nothing has yet been expelled. In the next phase, also termed the expulsive phase, intense pressure is formed in the stomach brought about by enormous shifts in both the diaphragm and the abdomen. These shifts are, in essence, vigorous contractions of these muscles that last for extended periods of time—much longer than a normal period of muscular contraction. The pressure is then suddenly released when the upper esophageal sphincter relaxes resulting in the expulsion of gastric contents. Individuals who do not regularly exercise their abdominal muscles may experience pain in those muscles for a few days. The relief of pressure and the release of endorphins into the bloodstream after the expulsion causes the vomiter to feel better.
Partially digested food, with man-sized glove for scale
The content of the vomitus (vomit) may be of medical interest. Fresh blood in the vomit is termed hematemesis ("blood vomiting"). Altered blood bears resemblance to coffee grounds (as the iron in the blood is oxidized) and, when this matter is identified, the term coffee-ground vomiting is used. Bile can enter the vomit during subsequent heaves due to duodenal contraction if the vomiting is severe. Fecal vomiting is often a consequence of intestinal obstruction or a gastrocolic fistula and is treated as a warning sign of this potentially serious problem (signum mali ominis).
If the vomiting reflex continues for an extended period with no appreciable vomitus, the condition is known as non-productive emesis or "dry heaves", which can be painful and debilitating.
An emetic, such as syrup of ipecac, is a substance that induces vomiting when administered orally or by injection. An emetic is used medically when a substance has been ingested and must be expelled from the body immediately. (For this reason, many toxic and easily digestible products such as rat poison contain an emetic. This presents no problem for the effectiveness of the rodenticide as rodents are unable to vomit.) Inducing vomiting can remove the substance before it is absorbed into the body.
Emetics can be divided into two categories, those which produce their effect by acting on the vomiting center in the medulla, and those which act directly on the stomach itself. Some emetics, such as ipecac, fall into both categories; they initially act directly on the stomach, while their further and more vigorous effect occurs by stimulation of the medullary center.
Salt water and mustard water, which act directly on the stomach, have been used since ancient times as emetics. Care must be taken with salt, as excessive intake can potentially be harmful.Copper sulfate was also used in the past as an emetic. It is now considered too toxic for this use.
To eliminate an ingested poison (some poisons should not be vomited as they may be more toxic when inhaled or aspirated; it is better to ask for help before inducing vomiting)
Some people who engage in binge drinking induce vomiting to make room in their stomachs for more alcohol consumption.
Participants of the Milk challenge typically end up vomiting most of the milk they consume, as proteins in the ingested milk (such as casein) rapidly denature and unravel on contact with gastric acid and protease enzymes, rapidly filling the stomach. Once the stomach becomes full, stretch receptors in the stomach wall trigger signals to vomit to expel any further liquid the participant ingests.
People suffering from nausea may induce vomiting in hopes of feeling better.
Overexertion (doing too much strenuous exercise can lead to vomiting shortly afterwards).
Rumination syndrome, an underdiagnosed and poorly understood disorder that causes patients to regurgitate food shortly after ingestion.
Projectile vomiting is vomiting that ejects the gastric contents with great force. It is a classic symptom of infantile hypertrophic pyloric stenosis, in which it typically follows feeding and can be so forceful that some material exits through the nose.
Antiemetics act by inhibiting the receptor sites associated with emesis. Hence, anticholinergics, antihistamines, dopamine antagonists, serotonin antagonists, and cannabinoids are used as antiemetics.
Evidence to support the use of antiemetics for nausea and vomiting among adults in the emergency department is poor. It is unclear if any medication is better than another or better than no active treatment.
Nausea and/or vomiting are the main complaints in 1.6% of visits to family physicians in Australia.
Society and culture
Herodotus, writing on the culture of the ancient Persians and highlighting the differences with those of the Greeks, notes that to vomit in the presence of others is prohibited among Persians.
A drunk man vomiting, while a young slave is holding his forehead. Brygos Painter, 500–470 BC
It is quite common that, when one person vomits, others nearby become nauseated, particularly when smelling the vomit of others, and often to the point of vomiting themselves. It is believed that this is an evolved trait among primates. Many primates in the wild tend to browse for food in small groups. Should one member of the party react adversely to some ingested food, it may be advantageous (in a survival sense) for other members of the party to also vomit. This tendency in human populations has been observed at drinking parties, where excessive consumption of alcoholic beverages may cause a number of party members to vomit nearly simultaneously, this being triggered by the initial vomiting of a single member of the party. This phenomenon has been touched on in popular culture: notorious instances appear in the films Monty Python's The Meaning of Life (1983) and Stand By Me (1986).
Intense vomiting in ayahuascaceremonies is a common phenomenon. However, people who experience "la purga" after drinking ayahuasca, in general, regard the practise as both a physical and spiritual cleanse and often come to welcome it. It has been suggested that the consistent emetic effects of ayahuasca—in addition to its many other therapeutic properties—was of medicinal benefit to indigenous peoples of the Amazon, in helping to clear parasites from the gastrointestinal system.
There have also been documented cases of a single ill and vomiting individual inadvertently causing others to vomit, when they are especially fearful of also becoming ill, through a form of mass hysteria.
Special bags are often supplied on boats for sick passengers to vomit into.
Most people try to contain their vomit by vomiting into a sink, toilet, or trash can, as vomit is difficult and unpleasant to clean. On airplanes and boats, special bags are supplied for sick passengers to vomit into. A special disposable bag (leakproof, puncture-resistant, odorless) containing absorbent material that solidifies the vomit quickly is also available, making it convenient and safe to store until there is an opportunity to dispose of it conveniently.
An online study of people's responses to "horrible sounds" found vomiting "the most disgusting". Professor Trevor Cox of the University of Salford's Acoustic Research Centre said, "We are pre-programmed to be repulsed by horrible things such as vomiting, as it is fundamental to staying alive to avoid nasty stuff." It is thought that disgust is triggered by the sound of vomiting to protect those nearby from possibly diseased food.
Emetophilia is sexual arousal from vomiting, or watching others vomit.Emetophobia is a phobia that causes overwhelming, intense anxiety pertaining to vomiting.
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