Reducing intracranial pressure in patients with traumatic brain injury Learn how to identify rising intracranial pressure early to promote appropriate interventions. By Cindy L. Zerfoss, MSN, RN, ACNP-CS (TBI) • increased neuronal oxygen con - TRAUMATIC BRAIN INJURY refers to blunt or penetrating head sumption from pain, anxiety, agi - injury that disrupts normal brain tation, fever, and shivering functioning, causing impaired think - (which increase metabolic de - ing and memory, personality mand) changes, and possible sensory and • environmental light and sound motor changes. Some people recov - • bathing er completely with no cognitive • repositioning in bed deficits; others remain in a persist - • seizures. Patients should receive ent vegetative state. seizure prophylaxis within the TBI occurs in all age groups, and first week after TBI; however, its incidence is increasing. It con - early posttraumatic seizures tributes to about 30% of all injury- aren’t associated with worse out - related deaths and accounts for comes. about 2.5 million emergency de - partment (ED) visits annually. shape, which can obstruct flow of ICP monitoring Although most TBIs cause only CSF and blood. We now know that not all the neu - mild effects, roughly 290,000 pa - rologic damage from TBI occurs at tients are hospitalized for TBI annu - Causes of increased ICP the time of injury. Some continues ally; of those, about 51,000 die. All nurses need to be able to iden - over several hours to days, so early However, over the past 3 decades, tify the factors that can increase recognition and treatment are cru - the overall mortality rate has de - ICP, which include: cial for optimizing patient outcome. clined from nearly 50% to approxi - Continuous ICP monitoring al - mately 25%. lows early identification of in - TBI commonly leads to elevated creased ICP. Not only does it reveal intracranial pressure (ICP), which CNE how the patient responds to routine 1.3 contact can have catastrophic conse - hours activities, such as turning, bathing, quences. ICP reflects the pressure and suctioning; it also promotes of the cranial contents—cere - LEARNING OBJECTIVES early interventions to treat rising brospinal fluid (CSF), brain tissue, 1. Describe the role of intracranial ICP before it climbs dangerously and blood. The cranial vault is a pressure (ICP) monitoring in pa - high. The consensus recommenda - fixed structure, so it can’t enlarge tients with traumatic brain injury. tion is to treat ICP above 20 mm when its contents expand. The sum 2. Discuss principles for monitoring Hg. Pupillary changes can occur at of the volumes of brain tissue, CSF, ICP. ICP as low as 18 mm Hg; hernia - and intracranial blood is constant; 3. Summarize methods for reducing tion, at ICP as low as 20 to 25 mm if one increases, one or both of the ICP. Hg. (See Assessment tools for pa - other two must decrease. Space- tients with neurologic injuries .) occupying conditions like tumors, The author and planners of this CNE activity have dis - The Brain Trauma Foundation closed no relevant financial relationships with any com - infection, and edema compromise mercial companies pertaining to this activity. recommends ICP monitoring for all brain tissue when they expand, TBI patients who: Expiration:10/1/19 causing brain structures to alter • are capable of recovering AmericanNurseToday.com October 2016 American Nurse Today 1 Assessment tools for patients with neurologic injuries sive and conservative measures and Emergency medical responders in the field and clinicians in emergency departments progressing to other measures as and neurologic intensive care units use the Glasgow Coma Scale (GCS) to gauge the needed. Some interventions may severity of neurologic injury. The patient’s score is based on the best eye opening, occur simultaneously, depending verbal, and motor responses. Ranging from 3 (deep coma) to 15 (fully awake), it’s obtained by totaling the best responses in all categories. GSC scores of 8 or lower on the patient’s specific needs and indicate severe TBI; 9 to 12, moderate TBI; and 13 to 15, mild TBI. ( Note: In the chart severity of increased ICP. below, “NT” denotes “not testable.”) First steps: Noninvasive and Score Eye opening Verbal response Motor response conservative measures • Elevate the head of the patient’s NT NT NT bed 30 to 45 degrees and ensure venous outflow isn’t obstructed 1 None None None from a kinked neck, constricting tape, or cervical collar. 2 To pressure Sounds Extension • Take steps to prevent shivering, which increases ICP. 3 To sound Words Abnormal flexion • Avoid hyperthermia, which can 4 Spontaneous Confused Normal flexion increase metabolic demand as much as 10% per degree C. 5 NA Oriented Localizing (Fever is a marker of poor out - come in TBI patients.) Be aware 6 NA NA Obeys commands that vasodilation from fever in - creases CPP, which in turn raises ICP. Increased air circulation Rancho Los Amigos Scale blankets, cooling catheters, and The Ranchos Los Amigos Scale (also called the Rancho Los Amigos Level of Cognitive antipyretics can be used to de - Functioning Scale) is used to monitor the patient’s readiness for rehabilitation after crease fever. emerging from a coma following severe TBI. Levels range from 1 (coma) to 8 • Take measures to optimize the (oriented and appropriate). Levels 2 and 3 reflect emergence from coma; levels 4 to patient’s blood pressure, avoid - 6, confusion with nonpurposeful to purposeful behaviors. Patients usually enter rehabilitation at level 4. Levels 7 and 8 show continued improvement and insight ing both hypotension and hyper - approaching the patient’s pre-injury level of functioning. tension. • Know that aggressive fluid resus - citation to drive CPP above 70 • have Glasgow Coma Scale (GCS) method involves placement of an mm Hg puts patients at risk for scores of 3 to 8 external ventricular drain (EVD) in acute respiratory distress syn - • have abnormal head computed the lateral ventricle using sterile drome. To avoid hypoxia, strive tomography (CT) scans. technique. Typically, this takes for an oxygen saturation above ICP monitoring also is recom - place either at the bedside or in the 90% or a partial pressure of arte - mended for all severe TBI patients operating room. Advantages of an rial O 2 (Pa O2) above 60 mm Hg. with normal head CT scans who EVD include reliable ICP monitor - • Catecholamine stress response are older than age 40 and show ing, system recalibration, excess in TBI patients can lead to hy - motor posturing (decorticate, decer - CSF drainage, and intrathecal med - perglycemia, which typically ebrate, or both) and systolic blood ication administration. warrants supplemental insulin. pressure below 90 mm Hg. In con - Alternatively, a parenchymal ICP Untreated hyperglycemia (blood junction with mean arterial blood monitor can be used, although it glucose level above 200 mg/dL) pressure (MAP) monitoring, ICP loses accuracy over time (drift) and is associated with worse neuro - monitoring is used to calculate can’t be recalibrated after it’s placed logic outcomes. Prolonged hy - cerebral perfusion pressure (CPP), in the brain. Also, a parenchymal poglycemia also is dangerous an indirect measure of cerebral per - catheter may not transduce accurate because it can reduce the fusion. (See Calculating cerebral measurements if placed at or near brain’s glucose supply, leading perfusion pressure .) the brain injury site. to neurologic deterioration. Ex - perts recommend starting blood Recommended ICP monitoring Methods for reducing ICP glucose monitoring at admission method ICP should be reduced in a step - and striving for normoglycemic The recommended ICP monitoring wise fashion, starting with noninva - status. The American College of American Nurse Today Volume 11, Number 10 AmericanNurseToday.com 2 Calculating cerebral perfusion pressure In patients with traumatic brain injury, cerebral perfusion pressure (CPP) is an important parameter because reduced CPP increases cerebral hypoxia risk. Optimal blood flow, providing cerebral CPP ranges from 50 to 70 mm Hg. CPP below 50 mm Hg is linked to a poor patient protection. The most commonly outcome. CPP is calculated using this equation: used barbiturate is pentobarbital. CPP = mean arterial pressure (MAP) − intracranial pressure (ICP) If ICP doesn’t decrease within the first 4 hours after this drug is given, it’s unlikely to lower ICP Surgeons recommends a blood plicably. If ICP remains elevated unless given in combination with glucose range between 80 and after antiseizure measures, the other drugs. Know that patients 180 mg/dL. However, optimal patient may require some of the on barbiturates won’t have a hyperglycemia treatment in se - interventions described next. pupillary response, so you’ll vere TBI remains controversial. need to rely on ICP monitoring Third steps: Continuous sedation for evidence of brain herniation. Second steps: Pharmacologic If elevated ICP persists despite con - Keep in mind that early changes interventions servative and pharmacologic meas - in pupillary response may indi - If the patient’s increased ICP ures, continuous sedation may be cate early herniation. doesn’t respond to first steps, phar - tried; this technique may reduce • For patients with per - Osmotics. macologic interventions are added. ICP by eliminating agitation and sistently elevated ICP, osmotic • To optimize blood pressure and pain. therapy may be used to expand improve cerebral perfusion, the • Opioids or benzodiazepines may blood volume by shifting fluid patient may require vasopressors be used for sedation; agitated from the brain’s extracellular to and I.V. fluid boluses to keep patients also may receive hyp - intravascular spaces. Osmotics systolic pressure above 90 mm notic or paralytic agents. These also reduce blood viscosity, Hg. Stay alert for side effects; de - drugs may be given individually which raises CPP and lowers pending on the agent used to or in combination. To minimize ICP. (See Understanding osmot - support blood pressure, the pa - hypotensive side effects, ensure ic therapy .) tient may experience tachycar - the patient has normal fluid vol - • The goal of Hyperventilation.