Death is the cessation of life, but where life ends and death begins is not always clear. In medical contexts, a distinction is drawn between cardiopulmonary death (irreversible cessation of heartbeat and respiration) and brain death (irreversible cessation of all brain and brainstem function). Considering that pronouncing death is usually a physician's responsibility, it is important to know the signs of death and the differences between reversible and irreversible clinical death. If there is a delay before death has been pronounced or the events leading up to death are unclear, knowing irreversible postmortem changes also helps in determining both the manner and time of death. These changes may be of medical and/or legal interest and include rigor mortis, livor mortis, Tardieu spots, and decomposition. When pronouncing death, it is important to understand the events leading up to death, if it was expected or not, and to conduct a careful examination before declaring the death and its time. Since addressing family and friends after death is a very emotional and vital responsibility, clinicians should be prepared by having a clear approach for dealing with this situation. In addition, special documentation must be handled, including writing a death note, death summary, and death certificate. Important steps should also be considered if the patient is a potential donor candidate or if a medical examiner/coroner should be notified for further investigation and possibly an autopsy. Clinical autopsies are performed for the purpose of medical diagnosis and research, while forensic (i.e., medicolegal) autopsies are performed for the purpose of establishing the cause and manner of death, especially if there is evidence of foul play.
- A number of ethically challenging scenarios may arise in the context of end-of-life care.
- At the end of life (as throughout life), the of medicine should be upheld and the physician should act in the best interest of the patient.
- Proper knowledge of the legal and ethical aspects of end-of-life care allows the physician to practice efficient and evidence-based medicine while respecting the patient's wishes.
- In disputes over end-of-life issues, the physician plays a key role in facilitating communication and emphasizing the importance of focusing on what patients themselves would have preferred.
- Death: : An ambiguous term referring to the cessation of life. Death can be diagnosed if a patient meets the criteria for brain death or cardiopulmonary death.
- Apparent death
Clinical death (somatic/systemic death): a term for the cessation of respiration and circulation
- May be reversible
- Some descriptions may also consider the loss of brain activity as a component of clinical death.
- Cardiopulmonary death: irreversible cessation of circulatory and respiratory functions
Brain death: irreversible, complete loss of function of the entire brain (including the brainstem), even if cardiopulmonary functions can be upheld by artificial life support
- Two physicians are required to make the legal diagnosis of brain death.
- See “” for more information.
- Intermediary life: the period of time between irreversible cardiopulmonary death and biological death
- Biological death (molecular/cellular death)
- Recognition of a person's death under the law
- Legal death comprises medically determined death (e.g., via a doctor's declaration of death) as well as the presumption under the law that a person is dead after a prolonged and unexplained absence with no signs of life (declaration of death in absentia).
Uniform determination of death act
- In the US, legal provisions regarding death and the clinical examinations or legal investigations it may entail vary from state to state.
- However, all states have adopted the “Uniform determination of death act” (1981), which specifies that the determination of death must be made in accordance with accepted medical standards and depends on either cardiopulmonary death or brain death.
- Understanding the signs of clinical death is important for correctly declaring death.
- Prematurely pronouncing death can have grave consequences, including neglecting potentially vital care, giving false alarms for organ donation, and unnecessary emotional stress for family members.
- Uncertain signs of death must be considered in relation to certain and irreversible signs of death, such as cardiopulmonary and brain death.
- If there is a delay before death has been pronounced or the events leading up to death are unclear, irreversible postmortem changes can help also in determining both the manner and time of death.
- Certain changes that necessarily occur after death may also occur in individuals who are still alive. They, therefore, cannot provide certainty of death. Such unreliable signs of death include:
- These signs must be considered in the context of determining cardiopulmonary death or brain death.
Cardiopulmonary death is the irreversible cessation of circulatory and respiratory functions. The following factors must be considered before making this determination:
- Monitoring of the patient for a specific period of time to confirm continuous apnea, unconsciousness, and lack of circulation
- Exclusion of factors that may be the cause of the cardiorespiratory arrest, such as:
- No intention of beginning or continuing cardiopulmonary resuscitation (CPR); prohibition of any intervention that might restore cerebral blood flow 
- Often synonymous with clinical death, but it is important to understand that clinical death is usually considered to be reversible
- The irreversible, complete loss of function of the entire brain (including the brainstem), even if cardiopulmonary functions can be upheld by artificial life support. 
Declaring brain death
Declaring brain death requires all of the following:
- Establish irreversible coma and the possible cause (e.g., acute severe damage to the CNS consistent with brain death as established by clinical or radiologic evidence).
- Brain death may not be established if one of the following is present in the patient:
- Absence of pupillary light reflex: nonreactive, midsized, or dilated pupils
Absence of ocular movements tested via:
- Vestibuloocular reflex (VOR)
Oculocephalic maneuver: a brainstem test in which the examiner rapidly rotates the patient's head from side to side or up and down and observes their eyes (while holding the eyelids open)
- Negative test (abnormal response, indicating brainstem injury): The patient's eyes will not move in their sockets and the gaze moves with the movement of the head.
- Positive test (normal response, indicating intact brainstem function): The patient's eyes will move in their sockets in the opposite direction to the movement of the head, maintaining the gaze fixed on the same point in space.
- Should only be performed if cervical spine integrity has been ensured.
- Absence of corneal reflex
- Absence of gag reflex and cough reflex (tested via tracheal suctioning or a tongue blade)
- No motor reaction to noxious stimulation of facial muscles (tested via deep pressure to the supraorbital ridge and temporomandibular joint)
- An essential part of the evaluation of brain death, proving the absence of brainstem respiratory control system reflexes
- Performed after all criteria for brain death have been met
- The following must be ensured for safe and accurate apnea testing:
- After preoxygenation with 100% oxygen, the patient is disconnected from the ventilator and observed for evidence of respiratory drive (such as gasps or chest movement).
- After 8–10 minutes, an arterial blood gas reading is obtained.
- pCO2 > 60 mm Hg and/or decreased pH < 7.30 when mechanical ventilation assistance is removed signifies an absence of respiratory drive, and the apnea test is considered positive.
- If the test is inconclusive, the procedure can be repeated for a longer period of time if the patient is hemodynamically stable.
Ancillary brain death tests
- These tests are only necessary if clinical examination and/or apnea testing are inconclusive or the patient is < 1 year of age.
- Suitable ancillary brain death tests are:
- Conditions that may mimic brain death
Conditions that may mimic brain function
- Spontaneous or reflexive complex motor activity (e.g., repetitive leg movements)
- Cyclical constriction and dilatation in light-fixed pupils
- False triggering of ventilator detection system for spontaneous breathing drive
Ethical issues concerning brain death 
- If a patient has been declared to have brain death, no consent is needed to withdraw life-sustaining therapy.
- The patient's family should be informed that the patient is being assessed for brain death as soon as the evaluation has started.
- The patient's family should be given a reasonable amount of time to visit the patient and accept the diagnosis before discontinuation of life-sustaining treatment. 
If the patient's family disagrees with a diagnosis of brain death:
- Discuss the family members' concerns with them; express empathy and respect for their position and provide additional information to eliminate any misunderstandings regarding the diagnosis. 
- Involving a hospital ethical committee may be helpful in resolving disagreements. 
- If the disagreement stems from religious or cultural beliefs, consider involving chaplains and/or local cultural leaders in the discussion. 
With the onset of death, all organisms undergo changes, mainly as a result of decomposition from putrefaction and autolysis, although external factors such as climate and location can also affect the state of a cadaver. Postmortem changes are signs of certain death that can provide information regarding the time, cause, mode, mechanism, and manner of death, as well as whether the location of the body corresponds to the place of death. These changes may be of medical and/or legal interest.
Early postmortem changes
- Rigor mortis
- Definition: purple-red discoloration of dependent areas of skin not exposed to pressure that begins 20–30 minutes after circulation stops due to blood settling under the force of gravity (hypostasis)
- At least 30 minutes to 2 hours after onset of death 
- Maximum observed at 6–12 hours 
- Location: blood pools in areas of dependency under the force of gravity 
- Color: the intensity of color depends on the amount of hemoglobin in the blood 
- Bluish-purple: normal lividity
- Greenish-red: hydrogen sulfide (produced in decaying organic matter) 
- Dark brown: phosphorus poisoning
- Brownish-red: poisoning with methemoglobin-forming substances (such as nitrite or aniline)
- Pale pink (barely pronounced): blood loss, severe anemia, severe hemorrhage
- Cherry red:
- Bright red: 
- Injuries incompatible with life (e.g., incineration, decapitation)
- Post mortem clots: separation of red blood cells and plasma creates clots of plasma that resemble “chicken fat” and blackish-red erythrocyte clots that resemble “currant jelly”
Livor mortis occurs approx. 30 minutes to 2 hours after the onset of death and is the first definite sign of death.
Late postmortem changes
Decomposition: breakdown of bone and tissue through aerobic and anaerobic processes
- Insect and other animal activity can further advance decomposition; entomological investigations of larval development can help determine the time of death.
- Casper's rule: a body will show similar marks of decomposition after one week of exposure to air, two weeks submerged underwater, and eight weeks of interment.
- Autolysis: aerobic decomposition through endogenous acids and enzymes in the stomach, pancreas, etc.
- Mummification: Warm environments with extremely low humidity can cause bodies to mummify and resist decomposition.
- Adipocere: Wet anaerobic environments (e.g., moors, bodies of water) may induce bacterial hydrolysis of fatty tissue (saponification), transforming tissue into a waxy substance called adipocere.
- Venous patterning (marbling): prominent purple discoloration of subdermal vessels
- Degloving: Thermal exposure, immersions, or advanced decomposition of skin and tissues result in degloving of skin (common in hands and feet).
- Vibices: pale marks caused by pressure (e.g. from a rope in hanging death or generally from tight clothing, e.g., socks, belt, and bra)
- Tardieu spots: dark pinpoint spots develop in dependent areas (e.g., in the legs of a hanged person due to increased gravitational pressure)
Life support and end-of-life issues
Orders and legal considerations in end-of-life care
A term used to describe a patient’s expressed preferences regarding cardiopulmonary resuscitation and endotracheal intubation; there are three possible codes:
- Full code: make all efforts to resuscitate
DNR: do-not-resuscitate order 
- A legal AD to withhold cardiopulmonary resuscitation or advanced cardiac life support in the setting of circulatory and respiratory cessation
- Typically, DNR orders include avoidance of other resuscitative measures as well (e.g., feeding tubes).
- DNR orders may be accompanied by do not intubate (DNI) orders.
- DNI: do-not-intubate order
- The term is unlikely to be familiar to a layperson; therefore it should not be used in discussion with patients or their family members.
- A patient's code status should be confirmed verbally with the patient or their appropriate surrogate at each hospital admission, regardless of the previous status, and documented. A patient's code status may nonetheless be unknown at the time vital interventions are necessary.
- A term used to describe a patient’s expressed preferences regarding cardiopulmonary resuscitation and endotracheal intubation; there are three possible codes:
Withdrawal of care 
- Patients with decision-making capacity (or their surrogate) have the right to refuse any form of treatment at any time, even if doing so would result in the patient's death.
- There is no ethical distinction between withholding care and withdrawing care at a later time.
- The physician should make an effort to understand the reasons behind the patient's decision for refusing treatment.
- Patients who opt to withdraw from treatment and have limited life expectancy may be approved for .
- Involve palliative care if necessary.
- Provide extra help and information for families that are interested, e.g., on chaplain services or accessing psychosocial counseling.
Futile treatment 
Medical treatment or intervention for a terminally ill patient that is deemed nonbeneficial by the healthcare team or family
- The concept of medical futility is vague and there are many interpretations of the practice; there is no universally accepted definition.
- Some believe that futility only applies to end-of-life care, while others apply the term to any medical intervention that appears to lack a significant medical benefit.
- The physician is not ethically obligated to provide treatment if it is considered medically futile.
- Treatment can be considered medically inappropriate or futile if:
- Medical treatment or intervention for a terminally ill patient that is deemed nonbeneficial by the healthcare team or family
No escalation of treatment (NEOT) designation
- An order to continue ongoing treatment but not initiate new or increase the intensity of ongoing treatment, regardless of patient status (comfort measures are generally exempt)
- Issued by a physician for a terminally ill patient who is not expected to benefit from treatment escalation
- Minimizes the potential for futile treatment and unnecessary patient harm while saving resources
Acts as an interim period in the transition from curative to palliative care
- Helps loved ones adjust to the fact that the patient is terminally ill
- Facilitates agreement between surrogate decision-makers and the care team regarding end-of-life issues
- Persistent vegetative state (PVS): The decision to maintain a patient in PVS depends on their advance directive or surrogate decision-maker and should be made with the patient's best interests in mind. 
Standardized forms for end-of-life care directives 
- Individuals with life-limiting conditions, multiple chronic conditions, or conditions that cause frailty can begin planning end-of-life care with their health care providers.
- Standardized advance directive forms such as the Medical Orders for Life-Sustaining Treatment and the Physician Orders for Life-Sustaining Treatment forms allow for documentation of the patient's preferences regarding end-of-life medical care, including the following:
- The advance directive form can be completed and signed either by the patient or, if the patient lacks capacity, a surrogate.
- The form is completed after a series of conversations between the patient and health care providers about the patient's medical condition, prognosis, and values and personal goals for end-of-life care.
- In contrast to a living will or healthcare proxy, which act only if the patient loses decision-making capacity, advance care directive forms apply independent of the decision-making capacity of the patient at the time of application.
Medical aid in dying
Physician-assisted dying 
- Physician provision of medication, intervention, or information to a patient to enable or accelerate their death
- Illegal in most states
- The U.S. Supreme Court has ruled three times that the laws of physician-assisted death are to be decided on a state-by-state basis.
- Active and intentional termination of a patient's life, usually by sedative or paralytic, performed by the physician at the explicit request of the patient
- Requires the full process of informed consent before initiation
- Currently illegal in the U.S.
Terminal sedation 
- The administration of sedative medication to a terminally ill patient to relieve intractable end-of-life pain
- Legal and distinct from euthanasia
- The intent must be to relieve pain rather than bring about death, even though doing so may hasten the dying process.
- Not an appropriate means of addressing suffering that is primarily existential (e.g., death anxiety). 
- Relies on the principle of double effect
- Laws regarding who is authorized to pronounce a person clinically and/or legally dead as well as who is authorized to order an investigation into the circumstances of death vary from state to state.
- If a patient dies while under care, it is generally the physician's responsibility to examine the body to pronounce the death and record the time. Clinicians may also be called to the bedside for declaration of death.
- In some states, registered nurses (especially in hospice settings) are authorized to pronounce death.
- If no physician or registered nurse is readily available, a medical examiner or coroner is called to the scene to declare death.
- Emergency response teams may pronounce a person “Dead on Arrival” (DOA) if certain criteria are met (e.g., obvious postmortem changes or injuries that are incompatible with life such as decapitation or evisceration of thoracic contents).
- The specific procedures vary depending on the clinical scenario (e.g., cardiac death vs. brain death). Signs of death aid in diagnosing certain death and determining the time of death.
If called to declare death, determine:
If it was expected or not
- If it was unexpected, efforts should be made to go immediately to the patient for assessment.
- Who has already been informed
- If family members are present
- If it was expected or not
Assess the patient 
- Confirm the patient ID
- Generally, evaluation should last at least 2–10 minutes. 
- Check for responses to tactile stimuli
- Look for signs of cessation of circulatory function with subsequent cessation of neurological function. ; 
- Consult a specialist if:
- Pronounce the time of death
Determine further information
- The circumstances surrounding the patient's death
Whether organ donation is planned (if known). If a deceased individual is a potential donor candidate and had not refused to donate organs or tissue (e.g., in a living will), the proper organ donation organization/team should be notified immediately.
- See “Solid organ transplantation” for more details.
- Whether an autopsy is planned or if a medical examiner/coroner should be notified to determine if an autopsy is necessary. Indications for notifying a medical examiner/coroner vary but may include any death associated with:
- If there is reason to notify a medical examiner/coroner, he or she will determine if an autopsy is necessary. Neither the body nor medical equipment should be removed until the medical examiner/coroner has confirmed it is acceptable to do so.
- Communicate with loved ones: See “ .”
- Complete documentation: See “Documentation of death.”
Documentation of death
Physicians should follow local institutional protocols. They generally include:
- Death note: a brief note of the patient's death in the medical record
- Death summary: detailed documentation of the hospital course (similar to a discharge summary)
- Completing the death certificate (see below)
- Adhering to criteria for notifying the medical examiner/coroner (see “Reportable types of death”)
- In the US, the authority to sign death certificates varies from state to state.
- Generally, physicians are authorized to sign death certificates when the manner of death is natural, whereas in, e.g., violent or suspicious deaths, the authority lies with a coroner or medical examiner.
- The U.S. Standard Certificate of Death provided by the CDC's National Center for Health Statistics (NCHS) records the following information:
- To be provided/verified by the funeral director
- Decedent's personal information (name, address, relations, race, education, occupation, etc.)
- Place of death
- Method and place of disposition
- Funeral facility information
- To be provided by the medical certifier
- Date and time of death (actual or presumed and when pronounced)
- Whether coroner/medical examiner was contacted
- Cause of death (immediate cause and conditions leading/contributing to the cause)
- Whether autopsy was performed
- Tobacco use
- Pregnancy or history of pregnancy
- Manner of death
- Date, time, place, and circumstances of injury
- Certifier information
- To be provided/verified by the funeral director
Reportable types of death
The initial postmortem examination may not provide conclusive information regarding the manner, cause, mechanism, or mode of death. In certain types of death, an investigation is required by law. The specific characteristics of death that require an investigation vary from state to state. Below is a selection of the types of death that most commonly require reporting:
- Undetermined death
- Suspicious/unusual/unnatural circumstances
- Fetal/infant death
- Sudden death when in apparent good health
- Abortion/criminal abortion (maternal or fetal)
- Death from injury
- Therapeutic death or circumstances suggesting gross negligence in a healthcare setting
- Death that may constitute threat to public health
- Death in jail/police custody
- Drug and/or chemical overdose or poisoning
Professionals involved in the investigation of death
- Elected government official tasked with running the investigation to determine the cause, time, and manner of deaths that occurred under unexpected, violent, and suspicious circumstances or in the absence of a physician
- Declares death; issues death certificates; initiates inquests; requests autopsies; qualifications, functions, and authority vary from state to state; does not require medical training
- Medical examiner: medically trained government official qualified to perform autopsies; otherwise similar functions and authority as coroner
- Forensic pathologist: establishes cause of death and performs autopsy upon the request of the medical examiner or coroner
- Death investigator: assists the medical examiner/coroner in investigating deaths, focusing on the collection of information on the decedent and guiding the investigation process.
- A legal inquiry before a coroner or medical examiner to establish the identity of the decedent and the time, place, cause, and manner of death.
- Often involves a jury; inquiries are conducted almost exclusively in the event of deaths taking place under unexpected, violent, or mysterious circumstances.
The first step in investigating a death is determining the manner by which a person died. If the manner of death is determined to be natural, a further investigation is not legally obligatory, while unnatural manners of death elicit an inquiry into the precise circumstances. The manner of death is distinct from the mode, cause, and mechanism of death in so far as the manner is the root cause of how the death occurred (e.g., “homicide” involving an axe attack), while the cause is the disease or injury that causes death (e.g., an “axe wound”), the mechanism is the physiological derangement that causes death (e.g., “exsanguination” due to an axe wound), and mode is the abnormal physiological state in an individual at the time of death (coma = failure of brain function, syncope = failure of heart function, asphyxia = failure of respiratory system; e.g., “coma” from axe wound). The manner of death is of particular importance because of the legal consequences that inevitably follow any unnatural manner of death.
- Natural manner of death
Unnatural manners of death: death caused by external events or a third party
- Accident: death from injury or poisoning without evidence of third party intent to kill or cause harm
- Suicide: death from intentional, self-inflicted injury or poisoning for the purpose of causing self-harm or death
- Homicide: death from intentional injury or poisoning committed by another person for the purpose of causing fear, harm, or death. Intent is a common element, but it is not required for classification.
- Could not be determined: applied to deaths in which the manner could not be determined even after consideration of all information available
- Pending investigation: if determination of the manner of death depends on further information
- Close examination of a body to determine the cause of death; typically involves dissection of the body
- Many states require that a pathologist performs the autopsy.
- However, in some states, autopsies may also be performed by medical examiners without a degree in pathology.
- Medical investigation into the cause of a natural death (i.e. does not consider the manner of death) and any pre-existing illnesses
- Diagnosis of diseases that can only be confirmed postmortem (e.g., Parkinson's disease) or where antemortem efforts failed
- Confirmation that the diagnosis made before death was correct and that the treatments administered were reasonable
- Requested by next of kin
- In life: patient or healthcare surrogate
- Postmortem: next of kin
- Medicolegal investigation into the circumstances of unexplained or (possibly) unnatural deaths
- Establishing the identity of the decedent and the time, place, and manner of death
- Collect forensic evidence
- Reconstruct a crime or accident
Characteristics of death that may require a forensic autopsy
- Deemed necessary or in the public interest by a coroner/medical examiner
- Request by the police, by the district attorney, or a court
- If circumstances of death are suspicious, unusual, unnatural, esp. homicide and suicide
- If cause of death poses a potential threat to public health
- Sudden fetus/infant deaths that appear natural and occur when in good health
- Suspected sudden infant death syndrome (SIDS)
Signs of vitality (vital reactions)
Signs of vitality (not to be confused with vital signs) are signs that a body was still alive at the time of having sustained damage as opposed to the damage having occurred postmortem.
- Signs of exsanguination
- Signs of venous obstruction
- Metabolism: metabolism of toxins (metabolites of toxins detectable in urine)
Central nervous system
- Soot-free radial bands beside the eyes (crow's feet) in individuals involved in a fire
- Evidence of a functioning autonomic nervous system at the time of injury: blood that has been swallowed or coughed up
Signs of vitality provide clues that damage to an organism occurred before the onset of death.
Supravital reactions are certain physical functions that persist for some time after the onset of death. They provide specific clues regarding the time of death.
Up to 8 hours after onset of death: skeletal musculature
- Up to 8 hours postmortem: Mechanical stimulation causes slight idiomuscular bulging that may persist for up to 24 hours.
- 3–5 hours postmortem: Mechanical stimulation causes pronounced reversible idiomuscular bulging.
- 1.5–2.5 hours postmortem: Zsako's muscle phenomenon, i.e., mechanical stimulation causes propagated excitation
- Up to 17 hours: pupillary response
- Up to 80 hours: motile sperm cells
Evidence of live birth
- Lung float test: Lungs that are lighter than water suggest that respiration occurred and that the infant was, therefore, alive at birth. The test is, however, unreliable as a variety of factors can lead to false-negative or false-positive results.
- Breslau's second life test: Air in the gastrointestinal tract provides clues as to how long an infant lived before dying. The further down there is air in the gastrointestinal tract, the higher the probability an infant survived birth.
Training healthcare providers on deceased patients
- Performing procedures on newly deceased patients can provide valuable hands-on training for inexperienced health care providers.
Training procedures may be performed if the deceased patient has consented through advanced directives.
- In the absence of an advanced directive, consent may be obtained from the next-of-kin.
- If the deceased patient's identity is unknown, health care providers may search through the patient's belongings and share the patient's personal information (e.g., social security number) with authorities to determine their identity and contact next-of-kin. 
- Performing any kind of unnecessary procedure on a deceased person's body without written consent from the patient or the next-of-kin is unethical, regardless of the procedure's degree of invasiveness.
- If consent is obtained, the patient's body should be treated with respect, and the educational/research procedures should be conducted according to a plan and under direct supervision of an expert.
- All procedures undertaken on the cadaver should be documented in the patient's medical record.