traumatic brain injury

skull fracture

• depressed skull fractures involve bone fragments driven into the underlying meninges of brain tissue; this often pres ents as a depression or dip when palpating the scalp

  • patients with depressed skull fractures may re. quire surgical management to remove bone fragments, repair the skull or dura, evacuate a hematoma, or repair other adjacent structures, such as blood vessels

• injury to the dura may cause a breach in a typically watertight sterile compartment, placing a patient at risk for meningitis; therefore, careful monitoring for signs and symptoms of infection, such as fever, neck pain and stiffness, and headache is important

• assessment of extra-ocular movements → detect impingement of cranial nerves

• nasogastric and nasotracheal intubation are AVOIDED to reduce the risk of passing the tube through fractured areas of the skull into the brain

skull fracture - csf

• drainage of csf from the ear or nose indicates injury to the DURA

• drainage from the ear (otorrhea) typically signifies a fracture in the middle fossa

• ecchymosis (bruising) behind the ear (battle sign) is a delayed sign of a basilar skull fracture in the middle fossa

• rhinorrhea (csf drainage from the nose) occurs with a fracture in the anterior fossa; “raccoon eyes”, a ring like pattern of bruising around the eyes, is a late sign of this type of fracture

identification of csf

• drainage fro the ear or nose may be mixed with blood, making identification of csf difficult

• a layering of fluids, with blood on the inside and csf in a yellowish ring on the outside (“the halo sign”, may appear when the area is wiped with gauze

• however, a more definitive test of the fluid for a substance called beta-2 transferrin is more effective in distinguishing csf and other body fluids

• patients may also report a sweet or salty taste if csf is draining into the pharynx

• a looze gauze dressing can be applied to the ear or nose to quantify the amount and character of drainage while allowing unobstructed drainage of the fluid

• skin around the site of drainage is kept clean and patients are advised to NOT blow their nose or perform incentive spirometry

concussion

• defined as any alteration in mental status resulting from trauma

• may or may not lose consciousness

  • loss of consciousness may last up to 30 minutes

• patients are unable to recall events leading up to the traumatic event and short-term memory is affected

• are not associated with structural abnormalities on radiographic imaging

recovery from concussion

• quick and complete

• some patients exhibit symptoms that last longer, particularly with repetitive concussive injuries

• symptoms may include headache, decreased attention span and concentration, sleep disturbances, anxiety, short term memory impairment, dizziness, irritability, emotional lability, fatigue, visual disturbances, noise and light sensitivity, difficulties with executive function

  • may last for months to years

• if postconcussion symptoms last longer than THREE months → postconcussive syndrome

• discharge teaching → criteria for follow-up and review of s/s

• prolonged bed rest does not contribute to improved outcome

• preventative strategies to avoid reinjury

assessment - physical examination

• two essential tenets of neurologic assessments

  • level of consciousness is the most sensitive indicator of increased icp

  • maximal stimulus must be applied to achieve the maximal patient response

• performing serial neurologic examinations that include evaluation of loc and motor and cranial nerve function is necessary to identify increased icp and prevent herniation syndrome

assessment of cognitive function

• assessed by asking three orientation questions regarding person, place, and time

• necessary to elicit an “embroidered” or specific history from the patient to facilitate the detection of subtle changes over time

• patient may learn to answer the same questions correctly because of repetition but may continue to appear confused when questioned further

• instead of asking the patient to state their location, ask the patient to recall what type of place they are in, or ask the name of the hospital, the city, and the state

assessment of level of arousal

• determines a patient’s capacity for wakefulness

• a maximum stimulus must be applied in a systematic and escalating manner to effectively elicit the patient’s best, or maximal response

• stimulate a patient first by calling their name, then by shouting the name, next by shaking, and then by applying central pain

• if the patient awakens readily, the ability to follow simple commands is assessed by asking the patient to move their extremities or “show two fingers”

• when asking a patient to grip or squeeze the evaluator’s hands, it is important to make sure that the person can squeeze and release the grip

• if a painful stimulus must be applied, the following techniques are used: squeeze the belly of the trapezius muscle with the thumb and first finger where the neck and shoulder meet, apply pressure over the supraorbital notch, or perform a sternal rub

• if a response is not elicited with these maneuvers, pressure may be applied to the nail beds of the patient’s fingers or toes by placing a pencil on the nail and rolling it back and forth while applying pressure

• 15-30 seconds

initial management

• initial assessment and treatment of the patient with tbi begins immediately after the insult, often with prehospital care providers

• prehospital treatment of the patient with a head injury focuses on rapid neurologic assessment, definitive airway management, and treatment of hypotension

• guidelines for prehospital management emphasize early correction of hypoxia and hypercarbia

• diagnostic testing is performed subsequent to the inital resuscitation to evaluate the need for immediate surgical intervention

  • typical tests include radiographs of the cervical spine and a ct scan of the brain

monitoring and controlling icp

• icp monitor is typically inserted by a neuosurgeon at the bedside or in the operating room

• icp monitoring is recommended for patients with severe head injury (gcs score lower than 8) and ct scan abnormalities on admission

• icp monitoring may also be considered when the ct scan is normal but the patient meets two or more of the following criteria: older than 40 years, posturing, or a sbp less than 90 mmHg

• nursing interventions to manage increased icp include maintaining body alignment as well as avoiding sharp turning of the head to one side and sharp hip flexion

tbi treatment algorithm gcs <9

• admission to icu

  • consult neurosurgery

  • begin seizure prophylaxis x 7 days

  • labs: cbc, bmp, pt/inr, ptt, abg, serum osm

• intubation (if not already performed)

• keep paco₂ 35-46, pao₂ >60

• hob > 30 degrees or reverse trendelenburg

• sbp > 90

• rapid correction of any coagulopathy

• establish central line access; arterial line

• maintain evoluemia

• optimize sedation and analgesia

• consider postpyloric tube placement for early enteral nutrition

• icp monitor in patients with a gcs 3-8 and an abnormal ct scan or provider discretion

maintaining cerebral perfusion

• involves control of icp and maintenance of map

• cpp is calculated by subtracting icp from map

  • cpp = map - icp

• maintainenance of cpp within the range of 50 to 70 mmHg prevents cerebral ischemia at the lower end and mitigates the risk for acute respiratory distress syndrome which has been shown to occur more frequently when cpp is pushed over the upper limit of 70 mmHg

monitoring fluid and electrolyte status

• administration of osmotic diuretics, insensible fluid loss, and pituitary gland dysfunction may be responsible for fluid and electrolyte disturbances in patients with tbi

• strict monitoring of intake and output as well as hemodynamic monitoring

• routine monitoring of serum osmolality is helpful in preventing excessive systemic dehydration when administering osmotic diuretics, such as mannitol or hypertonic saline

• surveillance of serum electrolytes allows for early identification and treatment of electrolyte abnormalities

siadh

• hyponatremia most commonly occurs

• retention of water and hemodilution

• leads to a lower concentration of sodium in the blood

• a transient phenomenon that can be treated with fluid restriction

• urinary output → decreased

• specific gravity → increased

• volume status → mildly increased

• serum sodium → decreased

• treatment → fluid restriction, judicious sodium replacement

diabetes insipidus

• cause of hypernatremia and hypovolemia that occurs commonly in patients with injury or ischemia in or around the pituitary gland

• diagnosed by increasing serum sodium level, low urine specific gravity, and increased urine output

• treatment includes aggressive fluid replacement that matches hourly fluid losses and the administration of exogenous adh (vasopressin)

• urinary output → increased

• specific gravity → decreased

• volume status → decreased

• serum sodium → increased

• treatment → administration of exogenous vasopressin, fluid replacement

managing cardiovascular complications

• myocardial stunning and transient decrease in cardiac may occur in severe tbi

• inversion of t waves and st segment elevation or depression may be noted

• serum cardiac enzyme levels, electrocardiography, and echocardiography

• hemodynamic monitoring devices

• dic

• prophylaxis of dvt