brain death n drowning

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INTRODUCTION- • In general Brain death is diagnosed if there is

irreversible loss of consciousness, absence of brainstem reflexes, and apnea

• In 1987, guidelines for the determination of brain death in children were published by a multisociety task force.

• They emphasized the importance of the history and clinical examination in determining the etiology of coma so that correctable or reversible conditions were eliminated.


INTRODUCTION-• Additionally, age-related observation periods and the

need for specific neurodiagnostic tests were recommended for children 1 yr of age.

• Several inherent weaknesses have been recognized

including: 1) limited clinical information at the time of publication,

2) uncertainty concerning the sensitivity and specificity of ancillary testing,

3) biologic rationale for the use of age-based criteria,

4) little direction as to whether, when, and how the diagnosis in neonates.


VARIOUS CONCEPTS


1) Exclusion of reversible causes of coma

• Such as CNS depressant Drug intoxications, including barbiturates, opioids, sedatives, intravenous and inhalation anesthetics, antiepileptic agents, and alcohols, muscle relaxants etc

• Metabolic disorders- severe metabolic disturbances capable of causing a potentially reversible coma,

including electrolyte/glucose abnormalities

• Hypothermia- A core body temperature of 35°C (95°F) should be achieved and maintained during examination and testing to determine death.


• Shock or persistent hypotension based on normal values for the patient’s age.

• Systolic blood pressure or MAP should be in an acceptable range (systolic blood pressure not 2 SDS below age-appropriate norm) based on age


Criteria For all practical purposes-

• Three steps involved are- 2) Ensuring the preconditions have been met

• The patient should be in apneic coma

Objectively Coma- The patient must exhibit complete loss of consciousness, vocalization, and volitional activity.

Must lack all evidence of responsiveness.

Eye opening or eye movement to noxiousstimuli is absent.


APNEA TEST-


APNEA TEST-

Prior to test, prexygenation 100% for 5-10 min. off IMV, under cardiac monitoring objectively

If no respiratory effort is observed from the initiation of the apnea test to the time the measured Paco2 60 mm Hg and 20 mm Hg above the baseline level, the apnea test is consistent with brain death.


2) Confirmation of absent brainstem reflexes and apnea-

Midposition or fully dilated pupils which do not respond to light.Absence of pupillary response to a bright light in both eyes( Usually pupils are fixed in midsize or dilated position 4-9 mm)

Deep pressure on the condyles at the level of the temporomandibular joints and deep pressure at the supraorbital ridge should produce no grimacing or facial muscle movement


• Absent gag, cough, sucking, and rooting reflex.

• The pharyngeal or gag reflex is tested after stimulation of the posterior pharynx with a tongue blade or suction device.

• The tracheal reflex- tested by examining the cough response to tracheal suctioning. The catheter should be inserted into the trachea and advanced to the level of the carina followed by one or two suctioning passes.


• Absent corneal reflexes.- demonstrated by touching the cornea with a piece of tissue paper, a cotton swab, or squirts of water. No eyelid movement should be seen.

• Absent oculovestibular reflexes- tested by irrigating each ear with ice water (caloric testing) after the patency of the external auditory canal is confirmed. The head is elevated to 30°. Each external auditory canal is irrigated (one ear at a time) with approximately 10–50 mL of ice water.

• Movement of the eyes should be absent during 1 min of observation. Both sides are tested with an interval of several minutes.


OTHER TESTS OF IMPORTANCE-• Oculocephalic reflex(doll’s eye)- Procedure- Manually rotate the patient's head

side to side and closely watch the position of the eyes.Should not be performed in a patient with a cervical spine injury

Observation- In an intact patient, the eyes remain fixed on a distant spot, as if maintaining eye contact with that spot. In a result consistent with brain death, the eyes move in concert with the patient's head movement.


• Some complex spinal movements may be particularly pronounced following removal of the ventilator

• The best-known series of movements is the Lazarus sign, which consists of extension of the upper extremities followed by flexion of the arms with the hands reaching to midsternal level. Flexion of the body at the waist may occur. A variety of other movements has been reported

Alert the family about….


Ancillary studies-• The committee recommends that ancillary studies are

not required to establish brain death and should not be viewed as a substitute for the neurologic examination

• They include electroencephalography and radionuclide cerebral blood flow

• Four-vessel intracranial contrast angiography has previously been used as the definitive confirmatory test, but practical technical difficulties and risks have led to the use of nuclear medicine scans


The role of ancillary studies-Ancillary studies may be used 1) when components of the examination or apnea testing cannot be completed safely because of the underlying medical condition

2) if there is uncertainty about the results of the neurologic examination

3) if a medication effect may be present or

4) to reduce the inter examination observation period


Special considerations in newborns-

• Preterm and term neonates 7 days of age were excluded from the 1987 Task Force guidelines.

• Diagnosis is uncertain because of the small number of braindead neonates reported in the literature and whether there are intrinsic biologic differences in neonatal brain metabolism, bloodflow, and response to injury.

• The newborn has patent sutures and an open fontanelle resulting in less dramatic increases in intracranial pressure after acute brain injury when compared with older patients.


Special considerations in neonates-• The cascade of events associated with increased

intracranial pressure and reduced cerebral perfusion ultimately leading to herniation is less likely to occur in the neonate

• Ancillary studies performed in the newborn 30 days of age are limited to ECS(electrocerebral silence) and measuring CBF

• Both these are less sensitive than in older children

• CBF is comparatively more sensitive than measuring electrical activity in diagnosing death


DEATH DECLERATION-

a. Death is declared after confirmation and completion of the second clinical examination and apnea test.

b. When ancillary studies are used, documentation of components from the second clinical examination that can be completed must remain consistent with brain death.


All aspects of the clinical examination, includingthe apnea test, or ancillary studies must be appropriately documented.

c. The clinical examination should be carried out by qualified clinicians includepediatric intensivists and neonatologists, pediatricneurologists and neurosurgeons; and pediatric trauma surgeons and pediatric anesthesiologistswith critical care training


1987 2011

Waiting period before initialbrain death examination

Not specified 24 hrs after cardiopulmonary resuscitation or severeacute brain injury is suggested if there areconcerns about the neurologic examination orif dictated by clinical judgment

Clinical examination Required required

Core body temperature Not specified 35°C (95°F)

Number of examinations Two examination; second examination not necessary in 2months to 1 yr age group if initial examination,EEG and concomitant cerebral blood flow consistent with brain death

Two examinations irrespective of ancillary studyresults (if ancillary testing is being done in lieu of initial examination elements that cannot besafely performed, the components of the secondexamination that can be done must becompleted)


Number of examiners Not specified Two (different attending physicians must performthe first and second exam

Observation interval between neurologic examinations

Age-dependent7 days to 2 months: 48 hrs2 months to 1 yr: 24 hrs1 yr: 12 hrs (24 hrs if HIE)

Age-dependentTerm newborn (37 wks gestation) to 30 days ofage: 24 hrs31 days to 18 yrs: 12 hrs

Reduction of observationperiod between examinations

Permitted only for 1 yr age group if EEG or cerebral blood flow consistent with brain death

Permitted for both age groups ifEEG or cerebral blood flowconsistent with brain death

Apnea testing Required, number of tests ambiguous

Two apnea tests required unless clinicallycontraindicated

Final pCO2 threshold forapnea testing

Not specified 60 mm Hg and 20 mm Hg above the baseline


Ancillary study recommended

Age-dependent7 days to 2 months: 2 EEGs separated by48 hrs2 months to 1 yr: 2 EEGs separated by 24hrs; cerebral blood flow can replace the need for second EEG 1 yr: no testing required

Not required except in cases in which the clinical examination and apnea test cannot beCompleted Term newborn (37 wks gestation) to 30 days ofAge: EEG or cerebral blood flow are less sensitive in this age group; cerebral bloodflow may be preferred30 days to 18 yrs: EEG and cerebral blood flow have equal sensitivity

Time of death Not specified Time of the second examination and apnea test (or completion of ancillary study and thecomponents of the second examination that can be safely completed)


SUBMERSION INJURY


Previous questions-1. Near drowning in children

2. An 18 month old child was brought to you after he fell upside down in a tub filled with water. Briefly describe the possible injuries and preventive strategies to avoid similar situation in future.

3. Describe the pathogenetic mechanism of injury in near drowning. Discuss the steps of initial resuscitation and subsequent hospital management.

4. Discuss the pathophysiology of submersion injury. A 4 year old boy was rescued 10 min back from a pond and rushed to the hospital emergency. Mention the basic principles of management.


epidemiology in relation to age-


Pathophysiology- conscious person initially panics, trying to surface, small

amounts of water enter the hypopharynx, triggering laryngospasm.

Progressive desaturation and the person soon loses consciousness from hypoxia.

Profound hypoxia and medullary depression lead to terminal apnea

By 3-4 min, the circulation abruptly fails because of myocardial hypoxia Ineffective cardiac contractions with electrical activity may occur briefly

Some drowning victims have a primary cardiac arrest secondary to a variant of an inherited prolonged QT syndrome.


COMPLICATIONS-BRAIN CNS injury is the most common cause of

mortality and long-term morbidity. Duration of anoxia associated with

irreversible damage is probably on the order of 3-5 min.

cerebral edema may occur, although the mechanism is not entirely clear. Severe cerebral edema can elevate intracranial pressure (ICP), contributing to further ischemia; and intracranial hypertension is an ominous sign


Complications-


COMPLICATIONS-


HYPOTHERMIA- • According to core body temperature, mild (34-36 C),

moderate (30-34 C), or severe (<30 C)

• Heat loss occurs both during and after the drowning

• Heat loss is mainly through conduction and convection

• Children are at increased risk for hypothermia because they have a relatively high ratio of body surface area to mass, decreased subcutaneous fat, and limited thermogenic capacity.


HYPOTHERMIA- EFFECTS

CVS

CNS

Most often hypothermia is a poor prognostic sign, and a neuroprotective effect has not been demonstrated. Buttheoretically it is possible for the brain to rapidly cool to a neuroprotective level until hemodynamically unstable, apnoea

With moderate to severe hypothermia, progressive bradycardia, impaired myocardial contractility, and loss of vasomotor tone contribute to inadequate perfusion, hypotension, and possible shock. At body temperature <28 C, extreme bradycardia, ventricular fibrillation (VF) or asystole can occur.


Hypothermia- • Victims who drown in water <60-70 F also experience

cold water shock, a dynamic series of cardiorespiratory physiologic responses.

• In human adults, immersion in icy water results in intense involuntary reflex hyperventilation and to a decrease in breath-holding ability to <10 seconds, which leads to fluid aspiration, contributing to more rapid and deep hypothermia. Severe bradycardia occurs in adults but is transient and rapidly followed by supraventricular and ectopic tachycardias and hypertension.


MANAGEMENT-

• INITIAL EVALUATION AND RESUSCITATION- Immediate CPR at the event site.

• The goal is to reverse the anoxia from submersion and prevent secondary hypoxic injury after submersion.

• When safe, institution of in-water resuscitation for nonbreathing victims by trained personnel may improve the likelihood of survival.

• Initial resuscitation must focus on rapidly restoring oxygenation, ventilation, and adequate circulation


MANAGEMENT-

• The airway should be clear of vomitus and foreign material, which may cause obstruction or aspiration.

• Abdominal thrusts should not be used for fluid removal because of chances of regurgitation and aspiration.

• In cases of suspected airway foreign body, chest compressions or back blows are preferable maneuvers


MANAGEMENT-• The cervical spine should be protected in anyone with

potential traumatic neck injury

• Breathing- If the pt. is apneic, begin ventilation with positive pressure bag and mask with 100% inspired oxygen

• If apnea, cyanosis, hypoventilation, or labored respiration persists, trained personnel should perform endotracheal tube (ET) intubation as soon as possible


Management-• Circulation- CPR should be instituted immediately in

pulseless, bradycardic, or severely hypotensive victims. • Continuously monitor the ECG and treat arrhythmias.

• Identify shock .

• Recognition and treatment of hypothermia are the unique aspects of cardiac resuscitation in the drowning victim.

• IV fluids and cardioactive medications are required to improve circulation and perfusion


DETECTION OF CT FINDING-• Early CT findings within 48 hours- range from normal

to diffuse cerebral edema• Later CT reveal diffuse loss of gray-white

differentiation with a uniform ground glass appearance of entire brain , indicating severe, global HIE process

• Other finding include reversal sign- decreased signals in the supratentorial compartment with relatve increase in density of the basal ganglia and brainstem

• Abnormal cranial CT poor prognosis


At the arrival at the ER-


In the PICU-


HYPOTHERMIA SALIENT POINTS-• (1) controlled hypothermia, such as that used in the

operating room before the onset of hypoxia or ischemia,

• (2) accidental hypothermia, such as occurs in drowning, which is uncontrolled and variable, with onset during or shortly after hypoxia-ischemia, and

• (3) therapeutic hypothermia, involving the purposeful and controlled lowering and maintenance of body (or brain) temperature at some time after a hypoxic-ischemic event.


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•THANK YOU


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brain death n drowning

Health & Medicine

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apnea test isconsistent

patients age

absent gag

absent corneal reflexes

eye movement

use of age

general brain death