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.
- Death: An ambiguous term referring to the cessation of life.
- 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
- 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:
- Cardiac and respiratory arrest
- Pale, dry, tight skin
- 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
- Definition: : the irreversible, complete loss of function of the entire brain (including the brainstem), even if cardiopulmonary functions can be upheld by artificial life support
- Practical steps for determination of brain death: The American Academy of Neurology has published a practical guide that consists of four steps. It cites specific measures and interpretations (e.g., limits of body temperature) that can be used to determine brain death, although not all of them are evidence-based.
- If brain death is proven, no consent is required to remove life support or other forms of treatment (e.g., antibiotic therapy).
- If the surrogate decision-maker disagrees with the physician's decision, it is judicious to consult a hospital's ethical committee.
- For further ethical and legal topics concerning brain death, see “Ethical issues concerning brain death” in the “Principles of medical law and ethics” article.
- Loss of brain function must be attributable to a specific cause (e.g., clinical or radiologic evidence of acute, severe damage to the CNS that is consistent with brain death).
- Irreversible loss of brain function
- Factors that may impede proper clinical judgment must be absent.
- Coma: no sign of arousal or awareness
- Absence of pupillary light reflex: nonreactive pupils that are either midsized or dilated
Absence of vestibuloocular reflex (VOR): normally, eye movement can be elicited by activating the semicircular canals of the vestibular system and mediated by the afferent sensory pathway of CN VIII and the efferent motor pathway of the contralateral CN VI and the ipsilateral CN III; can be tested via:
- Oculocephalic maneuver: used to test VOR by observing the patient's eye movement while stimulating the vestibular system
- Caloric test: used to test VOR by stimulating the vestibular system
- Absence of corneal reflex, gag reflex, and cough reflex
- No motor reaction to noxious stimulation of limbs or face
- Apnea (absence of breathing drive): lack of respiratory response to increased pCO2 > 60 mm Hg and/or decreased pH < 7.30 when mechanical ventilation assistance is removed
Factors that falsely suggest cerebral function
- Spontaneous or reflexive complex motor activity (e.g., repetitive leg movements)
- False triggering of ventilator detection system for spontaneous breathing drive
Ancillary brain death tests
- Only to be performed if clinical examination and/or apnea testing are inconclusive, or if patient is < 1 year
- One ancillary test is sufficient; suitable ancillary brain death tests are:
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)
- 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 “Organ donation considerations after death” 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.
- Address family and friends: see below
- Complete documentation: see below
If family or friends are present: 
- Introduce yourself (e.g., “I am Dr. X. I am one of the doctors on the team taking care of “Mr. Y” or “I am covering for the doctors taking care of Mr. Y”) and explain why you are there (e.g., “I regret to inform you that Mr. Y has died”).
- If possible, sit with the caregivers or family members.
- Be direct in disclosing the death and avoid any euphemisms that may be ambiguous.
- Offer condolences (e.g., “I'm so sorry for your loss”).
- Offer them the opportunity to step out of the room for a few minutes while you pronounce the death.
- Solicit extra help and information for families that are interested, including assisting in finding psychosocial counseling.
- Helpful resources include:
- Take some time to process the patient's death.
- Your response to a patient's death will depend on the specific circumstances, e.g., whether the death was expected or unexpected and your relationship with the patient.
- It is okay (and healthy) to express emotions.
- Find a coping mechanism that works well for you.
- Speak with family, friends, and other members of your support system.
- Reflect on the care provided to the patient, particularly considering any positive contributions you have made to their care.
- Depending on your relationship with the patient, sending condolences to a patient's family may help them to process the death.
- If the death occurs in the middle of a busy shift and you do not have a lot of time to cope in the moment:
- Make sure to take even a few minutes before seeing your next patient to process your emotions, while taking additional time after your shift.
- Taking time to provide support to the patient's family can be helpful, if appropriate.
- Consider checking in with a peer, senior resident, or attending.
- Think about the ways you will be working to help your next patient(s).
- Use this opportunity to reflect on end-of-life care in general (see “End-of-life issues” in “Principles of medical law and ethics”).
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: congestive hemorrhage, Perthes pressure congestion
- Metabolism: metabolism of toxins (metabolites of toxins detectable in urine)
- Central nervous system
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.