Brain Death Assessment PDF

Brain Death Assessment Dr. Haya Abu Maloh  Outline Definition of Brain death Determination of brain death Clinical testing: Brainstem reflexes Motor testing Apnea testing Ancillary Tests  Definition of Brain death Brain death is defined as complete and permanent...

Brain Death Assessment Dr. Haya Abu Maloh  Outline Definition of Brain death Determination of brain death Clinical testing: Brainstem reflexes Motor testing Apnea testing Ancillary Tests  Definition of Brain death Brain death is defined as complete and permanent loss of all functions of the brain, including those of the brainstem (irreversible loss of brain functions, including the brainstem), expressed as an unresponsive coma with loss of brainstem reflexes, and the ability to breathe spontaneously The three essential findings in brain death are coma, absence of brainstem reflexes, and apnea. An evaluation for brain death should be considered in patients who have suffered a massive, irreversible brain injury of identifiable cause. A patient determined to be brain dead is legally and clinically dead  Determination of brain death The process for brain death certification includes: 1. Identification of history or physical examination findings that provide a clear etiology of brain dysfunction. The determination of brain death requires the identification of the proximate cause and irreversibility of coma. Severe head injury, hypertensive intracerebral hemorrhage, aneurysmal subarachnoid hemorrhage, hypoxic-ischemic brain insults and acute liver failure are potential causes of irreversible loss of brain function. 2. Exclusion of any condition that might confound the subsequent examination of cortical or brain stem function. The conditions that may confound clinical diagnosis of brain death are: a. Shock/ hypotension b. Hypothermia -temperature < 32°C c. Severe electrolyte, acid-base, or endocrine disturbance d. Drugs known to alter neurologic, neuromuscular function and electroencephalographic testing, like anaesthetic agents, neuroparalytic drugs, barbiturates, benzodiazepines, alcohols  It must be proven that the brain injury is irreversible, meaning that loss of function is complete and constant over time. An observation period should be utilized. However, in the setting of resuscitation following cardiac arrest, at least a 24-h waiting period is recommended because there may be delayed recovery of brainstem function. In general, if there is any uncertainty regarding the irreversibility of the condition, further observation is recommended to exclude any doubt.  Clinical testing: Brainstem reflexes After establishing a comatose state with complete unresponsiveness to maximal stimuli, determination of brain death includes assessment for loss of brainstem reflexes, as follows: Loss of pupillary responsiveness, Loss of corneal reflex, Loss of oculocephalic reflex, Loss of oculovestibular, gag, and cough reflexes, Absence of facial movement to noxious stimuli, Absence of cerebrally mediated movement to noxious stimulation of the extremities  Pupillary light reflex Loss of pupillary reflex (light reflex): Pupils should be fixed in mid-size or dilated (4 to 9 mm) and not reactive to light; a magnifying glass or pupillometer can be used to evaluate further if results are equivocal. "Pupillary Reflex Testing During Brain Death Examinat ion" by David Urion for OPENPediatrics (youtube.com)  Corneal reflex A definitive corneal reflex test should be performed by touching a cotton swab on a stick such as a Q-tip to the outer edge of the iris, applying enough pressure to depress the globe. Care should be taken not to damage the cornea. In an absent reflex, no eyelid movement is seen. "Corneal Reflex Testing During Brain Death Examinati on" by David Urion for OPENPediatrics - YouTube  Oculocephalic reflex (OCR) The head is moved horizontally to both sides. In an absent reflex, there is no movement of the eyes relative the head. OCR can also be tested vertically if desired. If a spinal cord injury or cervical spine instability has not been ruled out, this test should not be performed. "Oculocephalic Reflex Testing During Brain Death Exa mination" by David Urion for OPENPediatrics (youtube.com)  Oculovestibular reflex (OVR) After elevating the head to 30 degrees and ensuring a clear pathway to an intact tympanic membrane, instill ice cold water into the ear canal with a syringe attached to a catheter for 60 s. The absence of an OVR will reveal no movement of the eyes. In a comatose patient with an otherwise intact brainstem, the eyes will deviate toward the irrigated ear, with nystagmus beating in the opposite direction. After 5 min, allowing for re-equilibration of the temperature of the endolymph on the tested ear, test the contralateral ear. "Oculovestibular Reflex Testing During Brain Death Exami nation" by David Urion for OPENPediatrics (youtube.com)  Pharyngeal Reflex Gag and cough reflex Using a suction catheter or tongue depressor, stimulate the posterior pharyngeal wall bilaterally. To test a cough reflex, stimulate the trachea near the carina with use of a deep endotracheal suction catheter, typically found connected to the endotracheal tube apparatus. The absence of a reaction to both tests is consistent with brain death. "Pharyngeal Reflex Testing During Brain Death Examin ation" by David Urion for OPENPediatrics (youtube.com)  Motor testing Apply deep pressure to the following points: the condyles at the level of the temporomandibular joints, the supraorbital notches, the sternal notch, and all four extremities proximally and distally. These measures should not elicit any movement that is not considered to be spinally mediated. Brain Death Testing Demo – YouTube  Apnea testing Apnea testing is used to examine the brain's ability to drive pulmonary function in response to the rise of carbon dioxide (CO2). Apnea testing is performed by the following procedure: Vasopressors: to maintain a systolic blood pressure ≥100 mm Hg. Preoxygenate is given for at least 10 minutes with a 100% fraction of inspired oxygen (FiO2) to a partial pressure of oxygen, arterial (PaO2) greater than 200 mmHg. Reduce ventilator frequency to 10 breaths per minute. Reduce positive end-expiratory pressure to 5 cm H2O.  If the peripheral capillary oxygen saturation (SPO2) remains greater than 95%, obtain baseline blood gas. Disconnect the patient from the ventilator, and preserve oxygenation with oxygen delivered through insufflation tubing given at 100% FiO2 at 6 L/min near the level of the carina through the endotracheal tube. Look for respiratory movements for 8 to 10 minutes. If no respiratory drive is observed, repeat blood gas at approximately 8 minutes. If no respiratory movements are observed, and PaCO2 is greater than 60 mmHg or 20 mm Hg increase in PaCO2 over a baseline PaCO2 (such as in chronic obstructive pulmonary disease), the apnea test result is positive.  If the above list is completed, and coma, the absence of brainstem reflexes, and a positive apnea test are present, the diagnosis of brain death can be made. The apnea test has to be aborted if: There is any respiratory movement (abdominal or chest excursions or brief gasp) Systolic blood pressure decreases to