Most drowning is preventable. It has been estimated that more than 85% of drownings could have been prevented by supervision, training in water skills, technology, regulation and public education.

Many pools and designated bathing areas either have lifeguards, a pool safety camera system for local or remote monitoring, or computer-aided drowning detection. However, bystanders play an important role in drowning detection and either intervention or the notification of authorities by phone or alarm.

The acronym "RID" was originated by Frank Pia to summarize important reasons why lifeguards may be unaware of a drowning. The term stands for "failure to recognize the struggle, the intrusion of non-lifeguard duties upon lifeguards' primary task-preventive lifeguarding, and the distraction from surveillance duties". In his paper on the RID factors, Pia makes a number of observations on the role, and the required behavior and training of lifeguards, as well as the importance of administrators directing lifeguards to this role and avoiding double tasking them (due to the very brief time of 20 – 60 seconds required for drowning to occur). He ended by summarizing the role of lifeguards as guardians of life, and that they should be directed exclusively to this duty and none other, while on surveillance, due to the high value placed on human life.

Appropriate clothing helps to prevent hypothermia. Synthetic and wool fabrics are superior to cotton as they provide better insulation when wet and dry. Some synthetic fabrics, such as polypropylene and polyester, are used in clothing designed to wick perspiration away from the body, such as liner socks and moisture-wicking undergarments. Clothing should be loose fitting, as tight clothing reduces the circulation of warm blood. In planning outdoor activity, prepare appropriately for possible cold weather. Those who drink alcohol before or during outdoor activity should ensure at least one sober person is present responsible for safety.

Covering the head is effective, but no more effective than covering any other part of the body. While common folklore says that people lose most of their heat through their heads, heat loss from the head is no more significant than that from other uncovered parts of the body. However, heat loss from the head is significant in infants, whose head is larger relative to the rest of the body than in adults. Several studies have shown that for uncovered infants, lined hats significantly reduce heat loss and thermal stress. Children have a larger surface area per unit mass, and other things being equal should have one more layer of clothing than adults in similar conditions, and the time they spend in cold environments should be limited. However children are often more active than adults, and may generate more heat. In both adults and children, overexertion causes sweating and thus increases heat loss.

Building a shelter can aid survival where there is danger of death from exposure. Shelters can be of many different types, metal can conduct heat away from the occupants and is sometimes best avoided. The shelter should not be too big so body warmth stays near the occupants. Good ventilation is essential especially if a fire will be lit in the shelter. Fires should be put out before the occupants sleep to prevent carbon monoxide poisoning. People caught in very cold, snowy conditions can build an igloo or snow cave to shelter.

The United States Coast Guard promotes using life vests to protect against hypothermia through the 50/50/50 rule: If someone is in water for 50 minutes, he/she has a 50 percent better chance of survival if wearing a life jacket. A heat escape lessening position can be used to increase survival in cold water.

Babies should sleep at 16-20 °C (61-68 °F) and housebound people should be checked regularly to make sure the temperature of the home is at least 18 °C (64 °F).

Rewarming can be done with a number of methods including passive external rewarming, active external rewarming, and active internal rewarming. Passive external rewarming involves the use of a person's own ability to generate heat by providing properly insulated dry clothing and moving to a warm environment. It is recommended for those with mild hypothermia.

Active external rewarming involves applying warming devices externally, such as a heating blanket. These may function by warmed forced air (Bair Hugger is a commonly used device), chemical reactions, or electricity. In wilderness environments, hypothermia may be helped by placing hot water bottles in both armpits and in the groin. These methods are recommended for moderate hypothermia. Active core rewarming involves the use of intravenous warmed fluids, irrigation of body cavities with warmed fluids (the chest or abdomen), use of warm humidified inhaled air, or use of extracorporeal rewarming such as via a heart lung machine or extracorporeal membrane oxygenation (ECMO). Extracorporeal rewarming is the fastest method for those with severe hypothermia. Survival rates with normal mental functioning have been reported at around 50%. Chest irrigation is recommended if bypass or ECMO is not possible.

Rewarming shock (or rewarming collapse) is a sudden drop in blood pressure in combination with a low cardiac output which may occur during active treatment of a severely hypothermic person. There was a theoretical concern that external rewarming rather than internal rewarming may increase the risk. These concerns were partly believed to be due to afterdrop, a situation detected during laboratory experiments where there is a continued decrease in core temperature after rewarming has been started. Recent studies have not supported these concerns, and problems are not found with active external rewarming.

Perinatal asphyxia is the medical condition resulting from deprivation of oxygen (hypoxia) to a newborn infant long enough to cause apparent harm. It results most commonly from a drop in maternal blood pressure or interference during delivery with blood flow to the infant's brain. This can occur as a result of inadequate circulation or perfusion, impaired respiratory effort, or inadequate ventilation. There has long been a scientific debate over whether newborn infants with asphyxia should be resuscitated with 100% oxygen or normal air. It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals, which have a role in reperfusion injury after asphyxia. Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen.

Smothering is the mechanical obstruction of the flow of air from the environment into the mouth and/or nostrils, for instance, by covering the mouth and nose with a hand, pillow, or a plastic bag. Smothering can be either partial or complete, where partial indicates that the person being smothered is able to inhale some air, although less than required. In a normal situation, smothering requires at least partial obstruction of both the nasal cavities and the mouth to lead to asphyxia. Smothering with the hands or chest is used in some combat sports to distract the opponent, and create openings for transitions, as the opponent is forced to react to the smothering.

In some cases, when performing certain routines, smothering is combined with simultaneous compressive asphyxia. One example is overlay, in which an adult accidentally rolls over onto an infant during co-sleeping, an accident that often goes unnoticed and is mistakenly thought to be sudden infant death syndrome. Other accidents involving a similar mechanism are cave-ins or when an individual is buried in sand or grain.

In homicidal cases, the term burking is often ascribed to a killing method that involves simultaneous smothering and compression of the torso. The term "burking" comes from the method William Burke and William Hare used to kill their victims during the West Port murders. They killed the usually intoxicated victims by sitting on their chests and suffocating them by putting a hand over their nose and mouth, while using the other hand to push the victim's jaw up. The corpses had no visible injuries, and were supplied to medical schools for money.

Coma has a wide variety of emotional reactions from the family members of the affected patients, as well as the primary care givers taking care of the patients. Common reactions, such as desperation, anger, frustration, and denial are possible. The focus of the patient care should be on creating an amicable relationship with the family members or dependents of a comatose patient as well as creating a rapport with the medical staff.

The treatment hospitals use on comatose patients depends on both the severity and cause of the comatose state. Although the best treatment for comatose patients remains unknown, hospitals usually place comatose patients in an Intensive Care Unit (ICU) immediately. Attention must first be directed to maintaining the patient's respiration and circulation, using intubation and ventilation, administration of intravenous fluids or blood and other supportive care as needed. Once a patient is stable and no longer in immediate danger, the medical staff may concentrate on maintaining the health of patient’s physical state. The concentration is directed to preventing infections such as pneumonias, bedsores (decubitus ulcers), and providing balanced nutrition. Infections may appear from the patient not being able to move around, and being confined to the bed. The nursing staff moves the patient every 2–3 hours from side to side and depending on the state of consciousness sometimes to a chair. The goal is to move the patient as much as possible to try to avoid bedsores, atelectasis and pneumonia. Pneumonia can occur from the person’s inability to swallow leading to aspiration, lack of gag reflex or from feeding tube, (aspiration pneumonia). Physical therapy may also be used to prevent contractures and orthopedic deformities that would limit recovery for those patients who awaken from coma.

A person in a coma may become restless, or seize and need special care to prevent them from hurting themselves. Medicine may be given to calm such individuals. Patients who are restless may also try to pull on tubes or dressings so soft cloth wrist restraints may be put on. Side rails on the bed should be kept up to prevent the patient from falling.

Methods to wake comatose patients include reversing the cause of the coma (i.e., glucose shock if low sugar), giving medication to stop brain swelling, or inducing hypothermia. Inducing hypothermia on comatose patients provides one of the main treatments for patients after suffering from cardiac arrest. In this treatment, medical personnel expose patients to “external or intravascular cooling” at 32-34 °C for 24 hours; this treatment cools patients down about 2-3 °C less than normal body temperature. In 2002, Baldursdottir and her coworkers found that in the hospital, more comatose patients survived after induced hypothermia than patients that remained at normal body temperature. For this reason, the hospital chose to continue the induced hypothermia technique for all of its comatose patients that suffered from cardiac arrest.

Exsanguination is the process of blood loss, to a degree sufficient to cause death. One does not have to lose all of one's blood to cause death. Depending upon the age, health, and fitness level of the individual, people can die from losing half to two-thirds of their blood; a loss of roughly one-third of the blood volume is considered very serious. Even a single deep cut can warrant suturing and hospitalization, especially if trauma, a vein or artery, or another comorbidity is involved. It is most commonly known as "bleeding to death" or colloquially as "bleeding out". The word itself originated from Latin: "ex" ("out of") and "sanguis" ("blood").

Exsanguination is a relatively uncommon cause of death in human beings. Traumatic injury can cause exsanguination if bleeding is not promptly controlled, and is the most common cause of death in military combat. Non-combat causes can include gunshot or stab wounds; motor vehicle crash injuries; suicide by severing arteries, typically those in the wrists; and partial or total limb amputation, such as via accidental contact with a circular or chain saw, or becoming entangled in operating machinery.

Patients can also develop catastrophic internal hemorrhages, such as from a bleeding peptic ulcer, postpartum bleeding or splenic hemorrhage, which can cause exsanguination without any external signs of distress. Another cause of exsanguination in the medical field is that of aneurysms. If a dissecting aortic aneurysm ruptures through the adventitia, massive hemorrhage and exsanguination can result in a matter of minutes.

Blunt force trauma to the liver, kidneys, and spleen can cause severe internal bleeding as well, though the abdominal cavity usually becomes visibly darkened as if bruised. Similarly, trauma to the lungs can cause bleeding out, though without medical attention, blood can fill the lungs causing the effect of drowning, or in the pleura causing suffocation, well before exsanguination would occur. In addition, serious trauma can cause tearing of major blood vessels without external trauma indicative of the damage.

Alcoholics and others with liver disease can also suffer from exsanguination. Thin-walled, normally low pressure dilated veins just below the lower esophageal mucosa called esophageal varices can become enlarged in conditions with portal hypertension. These may begin to bleed, which with the high pressure in the portal system can be fatal. The often causative impaired liver function also reduces the availability of clotting factors (many of which are made in the liver), making any rupture in vessels more likely to cause a fatal loss of blood.

For newborn infants starved of oxygen during birth there is now evidence that hypothermia therapy for neonatal encephalopathy applied within 6 hours of cerebral hypoxia effectively improves survival and neurological outcome. In adults, however, the evidence is less convincing and the first goal of treatment is to restore oxygen to the brain. The method of restoration depends on the cause of the hypoxia. For mild-to-moderate cases of hypoxia, removal of the cause of hypoxia may be sufficient. Inhaled oxygen may also be provided. In severe cases treatment may also involve life support and damage control measures.

A deep coma will interfere with body's breathing reflexes even after the initial cause of hypoxia has been dealt with; mechanical ventilation may be required. Additionally, severe cerebral hypoxia causes an elevated heart rate, and in extreme cases the heart may tire and stop pumping. CPR, defibrilation, epinephrine, and atropine may all be tried in an effort to get the heart to resume pumping. Severe cerebral hypoxia can also cause seizures, which put the patient at risk of self-injury, and various anti-convulsant drugs may need to be administered before treatment.

There has long been a debate over whether newborn infants with cerebral hypoxia should be resuscitated with 100% oxygen or normal air. It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals, which have a role in reperfusion injury after asphyxia. Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen.

Brain damage can occur both during and after oxygen deprivation. During oxygen deprivation, cells die due to an increasing acidity in the brain tissue (acidosis). Additionally, during the period of oxygen deprivation, materials that can easily create free radicals build up. When oxygen enters the tissue these materials interact with oxygen to create high levels of oxidants. Oxidants interfere with the normal brain chemistry and cause further damage (this is known as "reperfusion injury").

Techniques for preventing damage to brain cells are an area of ongoing research. Hypothermia therapy for neonatal encephalopathy is the only evidence-supported therapy, but antioxidant drugs, control of blood glucose levels, and hemodilution (thinning of the blood) coupled with drug-induced hypertension are some treatment techniques currently under investigation. Hyperbaric oxygen therapy is being evaluated with the reduction in total and myocardial creatine phosphokinase levels showing a possible reduction in the overall systemic inflammatory process.

In severe cases it is extremely important to act quickly. Brain cells are very sensitive to reduced oxygen levels. Once deprived of oxygen they will begin to die off within five minutes.

Mild and moderate cerebral hypoxia generally has no impact beyond the episode of hypoxia; on the other hand, the outcome of severe cerebral hypoxia will depend on the success of damage control, amount of brain tissue deprived of oxygen, and the speed with which oxygen was restored.

If cerebral hypoxia was localized to a specific part of the brain, brain damage will be localized to that region. A general consequence may be epilepsy. The long-term effects will depend on the purpose of that portion of the brain. Damage to the Broca's area and the Wernicke's area of the brain (left side) typically causes problems with speech and language. Damage to the right side of the brain may interfere with the ability to express emotions or interpret what one sees. Damage on either side can cause paralysis of the opposite side of the body.

The effects of certain kinds of severe generalized hypoxias may take time to develop. For example, the long-term effects of serious carbon monoxide poisoning usually may take several weeks to appear. Recent research suggests this may be due to an autoimmune response caused by carbon monoxide-induced changes in the myelin sheath surrounding neurons.

If hypoxia results in coma, the length of unconsciousness is often indicative of long-term damage. In some cases coma can give the brain an opportunity to heal and regenerate, but, in general, the longer a coma, the greater the likelihood that the person will remain in a vegetative state until death. Even if the patient wakes up, brain damage is likely to be significant enough to prevent a return to normal functioning.

Long-term comas can have a significant impact on a patient's families. Families of coma victims often have idealized images of the outcome based on Hollywood movie depictions of coma. Adjusting to the realities of ventilators, feeding tubes, bedsores, and muscle wasting may be difficult. Treatment decision often involve complex ethical choices and can strain family dynamics.

Hypoxic hypoxia is a result of insufficient oxygen available to the lungs. A blocked airway, a drowning or a reduction in partial pressure (high altitude above 10,000 feet) are examples of how lungs can be deprived of oxygen. Some medical examples are abnormal pulmonary function or respiratory obstruction. Hypoxic hypoxia is seen in patients suffering from chronic obstructive pulmonary diseases (COPD), neuromuscular diseases or interstitial lung disease.

There is ongoing research on the treatment of ARDS by interferon (IFN) beta-1a to aid in preventing leakage of vascular beds. Traumakine (FP-1201-lyo), is a recombinant human IFN beta-1a drug developed by Faron pharmaceuticals, is undergoing international phase-III clinical trials after an open-label, early-phase trial showed a 81% reduction-in-odds of 28-day mortality in ICU patients with ARDS. The drug is known to function by enhancing lung CD73 expression and increasing production of anti-inflammatory adenosine, such that vascular leaking and escalation of inflammation are reduced.

Acute alcohol poisoning is a medical emergency due to the risk of death from respiratory depression and/or inhalation of vomit if emesis occurs while the patient is unconscious and unresponsive. Emergency treatment for acute alcohol poisoning strives to stabilize the patient and maintain a patent airway and respiration, while waiting for the alcohol to metabolize. This can be done by removal of any vomitus or, if patient is unconscious or has impaired gag reflex, intubation of the trachea using an endotracheal tube to maintain adequate airway:

Also:

- Treat hypoglycaemia (low blood sugar) with 50 ml of 50% dextrose solution and saline flush, as ethanol induced hypoglycaemia is unresponsive to glucagon.

- Administer the vitamin thiamine to prevent Wernicke-Korsakoff syndrome, which can cause a seizure (more usually a treatment for chronic alcoholism, but in the acute context usually co-administered to ensure maximal benefit).

- Apply hemodialysis if the blood concentration is dangerously high (>400 mg/dL), and especially if there is metabolic acidosis.

- Provide oxygen therapy as needed via nasal cannula or non-rebreather mask.

- Provide parenteral Metadoxine.

Additional medication may be indicated for treatment of nausea, tremor, and anxiety.

To date, no prospective controlled clinical trial has shown a significant mortality benefit of exogenous surfactant in adult ARDS.

A normal liver detoxifies the blood of alcohol over a period of time that depends on the initial level and the patient's overall physical condition. An abnormal liver will take longer but still succeeds, provided the alcohol does not cause liver failure.

People having drunk heavily for several days or weeks may have withdrawal symptoms after the acute intoxication has subsided.

A person consuming a dangerous amount of alcohol persistently can develop memory blackouts and idiosyncratic intoxication or pathological drunkenness symptoms.

Long-term persistent consumption of excessive amounts of alcohol can cause liver damage and have other deleterious health effects.

There is limited evidence that the hypnotic drug zolpidem has an effect. The results of the few scientific studies that have been published so far on the effectiveness of zolpidem have been contradictory.

Marine-derived omega-3 polyunsaturated fatty acids (PUFAs) has been promoted for the prevention of sudden cardiac death due to its postulated ability to lower triglyceride levels, prevent arrhythmias, decrease platelet aggregation, and lower blood pressure. However, according to a recent systematic review, omega-3 PUFA supplementation are not being associated with a lower risk of sudden cardiac death.

Poena cullei (from Latin 'penalty of the sack') under Roman law was a type of death penalty imposed on a subject who had been found guilty of parricide. The punishment consisted of being sewn up in a leather sack, sometimes with an assortment of live animals, and then being thrown into water. The punishment may have varied widely in its frequency and precise form during the Roman period. For example, the earliest fully documented case is from ca. 100 BCE, although scholars think the punishment may have developed about a century earlier (earlier than that, murderers, including parricides, would be handed over to the aggrieved family for punishment, rather than punishment being enacted by Roman state officials). Inclusion of live animals in the sack is only documented from Early Imperial times, and at the beginning, only snakes are mentioned. At the time of Emperor Hadrian (2nd century CE), the most well known form of the punishment was documented, where a cock, a dog, a monkey and a viper were inserted in the sack. However, at the time of Hadrian "poena cullei" was made into an optional form of punishment for parricides (the alternate being thrown to the beasts in the arena). During the 3rd century CE up to the accession of Emperor Constantine, "poena cullei" fell out of use; Constantine revived it, now with only serpents to be added in the sack. Well over 200 years later, Emperor Justinian reinstituted the punishment with the four animals, and "poena cullei" remained the statutory penalty for parricides within Byzantine law for the next 400 years, when it was replaced with the punishment for parricides to be burnt alive instead.

"Poena cullei" gained a revival of sorts in late medieval and early modern Germany, with late cases of being drowned in a sack along with live animals being documented from Saxony in the first half of the 18th century.

There are three main causes of PVS (persistent vegetative state):

1. Acute traumatic brain injury

2. Non-traumatic: neurodegenerative disorder or metabolic disorder of the brain

3. Severe congenital abnormality of the central nervous system

Medical books (such as Lippincott, Williams, and Wilkins. (2007). In A Page: Pediatric Signs and Symptoms) describe several potential causes of PVS, which are as follows:

- Bacterial, viral, or fungal infection, including meningitis

- Increased intracranial pressure, such as a tumor or abscess

- Vascular pressure which causes intracranial hemorrhaging or stroke

- Hypoxic ischemic injury (hypotension, cardiac arrest, arrhythmia, near-drowning)

- Toxins such as uremia, ethanol, atropine, opiates, lead, colloidal silver

- Trauma: Concussion, contusion

- Seizure, both nonconvulsive status epilepticus and postconvulsive state (postictal state)

- Electrolyte imbalance, which involves hyponatremia, hypernatremia, hypomagnesemia, hypoglycemia, hyperglycemia, hypercalcemia, and hypocalcemia

- Postinfectious: Acute disseminated encephalomyelitis (ADEM)

- Endocrine disorders such as adrenal insufficiency and thyroid disorders

- Degenerative and metabolic diseases including urea cycle disorders, Reye syndrome, and mitochondrial disease

- Systemic infection and sepsis

- Hepatic encephalopathy

In addition, these authors claim that doctors sometimes use the mnemonic device AEIOU-TIPS to recall portions of the differential diagnosis: Alcohol ingestion and acidosis, Epilepsy and encephalopathy, Infection, Opiates, Uremia, Trauma, Insulin overdose or inflammatory disorders, Poisoning and psychogenic causes, and Shock.

The lack of generally recognized clinical recommendations available are a reflection of the dearth of data on the effectiveness of any particular clinical strategy, but on the basis of present evidence, the following may be relevant:

- Epileptic seizure control with the appropriate use of medication and lifestyle counseling is the focus of prevention.

- Reduction of stress, participation in physical exercises, and night supervision might minimize the risk of SUDEP.

- Knowledge of how to perform the appropriate first-aid responses to seizure by persons who live with epileptic people may prevent death.

- People associated with arrhythmias during seizures should be submitted to extensive cardiac investigation with a view to determining the indication for on-demand cardiac pacing.

- Successful epilepsy surgery may reduce the risk of SUDEP, but this depends on the outcome in terms of seizure control.

- The use of anti suffocation pillows have been advocated by some practitioners to improve respiration while sleeping, but their effectiveness remain unproven because experimental studies are lacking.

- Providing information to individuals and relatives about SUDEP is beneficial.

An implantable cardioverter defibrillator (ICD) is a battery powered device that monitors electrical activity in the heart and when an arrhythmia or asystole is detected is able to deliver an electrical shock to terminate the abnormal rhythm. ICDs are used to prevent sudden cardiac death (SCD) in those that have survived a prior episode of sudden cardiac arrest (SCA) due to ventricular fibrillation or ventricular tachycardia (secondary prevention). ICDs are also used prophylactically to prevent sudden cardiac death in certain high risk patient populations (primary prevention).

Numerous studies have been conducted on the use of ICDs for the secondary prevention of SCD. These studies have shown improved survival with ICDs compared to the use of anti-arrhythmic drugs. ICD therapy is associated with a 50% relative risk reduction in death caused by an arrhythmia and a 25% relative risk reduction in all cause mortality.

Primary prevention of SCD with ICD therapy for high risk patient populations has similarly shown improved survival rates in a number of large studies. The high risk patient populations in these studies were defined as those with severe ischemic cardiomyopathy (determined by a reduced left ventricular ejection fraction (LVEF)). The LVEF criteria used in these trials ranged from less than or equal to 30% in MADIT-II to less than or equal to 40% in MUSTT.

Therapeutic hypothermia has been attempted to improve results post brain ischemia . This procedure was suggested to be beneficial based on its effects post cardiac arrest. Evidence supporting the use of therapeutic hypothermia after brain ischemia, however, is limited.

A closely related disease to brain ischemia is brain hypoxia. Brain hypoxia is the condition in which there is a decrease in the oxygen supply to the brain even in the presence of adequate blood flow. If hypoxia lasts for long periods of time, coma, seizures, and even brain death may occur. Symptoms of brain hypoxia are similar to ischemia and include inattentiveness, poor judgment, memory loss, and a decrease in motor coordination. Potential causes of brain hypoxia are suffocation, carbon monoxide poisoning, severe anemia, and use of drugs such as cocaine and other amphetamines. Other causes associated with brain hypoxia include drowning, strangling, choking, cardiac arrest, head trauma, and complications during general anesthesia. Treatment strategies for brain hypoxia vary depending on the original cause of injury, primary and/or secondary.

When someone presents with an ischemic event, treatment of the underlying cause is critical for prevention of further episodes.

Anticoagulation with warfarin or heparin may be used if the patient has atrial fibrillation.

Operative procedures such as carotid endarterectomy and carotid stenting may be performed if the patient has a significant amount of plaque in the carotid arteries associated with the local ischemic events.