NR 446 Exam 3 Study Guide

NR 446 Exam 3 Study Guide Latest 2023 / 2024

Neuro

12 questions – Topics

• Increased intracranial pressures

• Signs and symptoms of increased ICP

▪ Early • Hypertension, tachycardia, tachypnea, doll eyes ▪ Late • Crushing triad (Late); Systolic Hypertension w/ widening pulse pressure, bradycardia, and irregular respirations.• Fixed dilated pupils ▪ GCS evaluation ( 15-9; good) (8-3; bad) (<3; coma)

• Intracranial Pressure Monitoring

▪ Monitoring is indicated for patients who have a GCS score between 3 and 8 due to a severe brain insult. This is used to assess response to therapy, or to augment neurological assessment.▪ ICP monitoring systems are classified by location of device or type of transducer

system:

• Ventricular • Parenchymal • Subarachnoid • Epidural ▪ Transducer system may be a microchip sensor device, fiberoptic catheter, or fluid-filled system. The fluid filled system is most often used for ICP monitoring.▪ ICP monitoring systems allow the nurse to observe an ICP waveform pattern.

• Treatment

▪ EVD

o Overall goals (from the PowerPoint):

▪ Maintain a patent airway ▪ ICP within normal limits ▪ Normal fluid and electrolyte balance ▪ No complications secondary to immobility and decreased LOC

• Prevent an increase in ICP.
• Once cause is discovered, management is centered on permanently decreasing the high

ICP, maintaining CPP, maintaining the airway, providing ventilation and oxygenation, and decreasing the metabolic demands placed on the injured brain.

• Maintain an ICP of less than 20 mmHg while maintaining the CPP above 70 mmHg.

Space nursing care to allow for rest period in between.

• Head of bed 30 degrees and neck in neutral position. This will help decrease MAP,

thereby decreasing CPP. 1 / 4

• May turn client side to side but monitor ICP during and it should return to baseline

within 5 minutes.

• Strict I&O’s. Avoid coughing, vomiting as they will increase ICP
• Avoid hyperthermia to help reduce metabolic demands. Lowering body temperature to

normal from a hyperthermic state or inducing hypothermia decreases cerebral metabolism, blood flow and volume, thereby decreasing ICP.

• Monitor for diabetes insipidus (polyuria, low urine specific gravity)
• Monitor for SIADH (Oliguria, high urine specific gravity)
• Monitor ICP. Avoid valsalve, coughing, sneezing, hypoxemia, and sudden arousal from

sleep because they could increase ICP.

• Reposition clients slowly and gently while monitoring ICP
• Avoid extreme hip flexion
• Protect client from injury
• Medications (ask professor what we need to know on the med chart at page 370, table

13-9) ▪ Adequate Oxygen with the goal being PaO2 greater than 80mmHg • Maintain airway vigilance • Mechanical ventilation like PEEP, but use with caution.• Adequate hematocrit ▪ Carbon Dioxide Management • PaCO2 35-45 mmHg • Avoid hyperventilation ▪ Diuretics • Osmotic diuretics are used to help reduce brain tissue volume

• Mannitol – Pulls water from brain interstitum into plasma
• Hypertonic saline

• Loop diuretics (such as Lasix) to help reduce brain tissue volume and to decrease CSF formation ▪ Fluid administration • Optimized fluid administration with isotonic solutions • Strict intake/output

• Goal: serum osmolality less than 320 mOsm/L

• Colloids or blood products to restore volume.▪ Blood Pressure

• Goal: MAP 70-90 mmHg

• CPP: at least 70 mmHg

• Avoid hypertension because it will increase cerebral blood volume • Nicardipine is used to help vasodilate (calcium channel blocker).▪ Metabolic Demands • Temperature control

• Induced hypothermia: Goal is to reach around 34-35 degrees C

• Sedation: Benzodiazepines, propofol, analgesia 2 / 4

• Seizure prophylaxis • Neuromuscular blockade

• Nursing interventions for clients with head injury

• Primary Brain Injury

▪ Direct injury that occurs to the brain from an impact.▪ With impact, the semisolid brain moves around inside the skull (think like whiplash from a car accident or something).▪ The area under the direct impact is injured, which is called coup injury.▪ Injury distal to the site of impact can occur as the brain moves inside the skull.This is called contrecoup injury.▪ Concussion • Occurs when a mechanical force of short duration is applied to the skull.This results in the temporary failure of impulse conduction.• Neurological deficits are reversible and are generally mild.▪ Contusion • Result of coup and contrecoup injuries, accompanied by bruising and bleeding into brain tissue.• Signs and symptoms are variable, depending on location and extent of bleeding.▪ Diffuse axonal injury • Widespread white matter axonal damage occurs secondary to rotational and shearing forces. This type of injury is associated with disruption of axons in the cerebral hemispheres, diencephalon, and brainstem.• Results in vasodilation and increased cerebral blood volume that precipitates increased ICP. Signs and symptoms are variable, prognosis is poor.▪ Penetrating injury • Result of low or high velocity forces such as gunshots, knives, or sharp objects.• With this type of injury, there is a deep laceration of brain tissue and possible damage to the ventricular system.• A low velocity (stabbing) injury is limited to the tract of entry, and the greatest concern is bleeding and infection.• A high velocity (gunshot) injury causes extensive damage because of the entry of bone fragments at the site. Bullets spin irregularly, they create many paths and shock waves that cause extensive brain damage.▪ Hematomas

• Life threatening. There are three types of hematomas: epidural,

subdural, and intracerebral.

o Epidural: collection of blood in the potential space between the

inner table of the skull and dura. Typically experiences a brief 3 / 4

loss of consciousness followed by a lucid period before neurological deterioration.

o Subdural: Collection of blood in the subdural space. Occurs

when a surface vein is torn around the cerebral cortex. Risk of death is high because of injury to brain tissue and the mass effect caused by an expanding hematoma.

o Intracerebral: hemorrhage into brain tissue that creates a mass

lesion. Lesion can occur anywhere in the brain and can be caused by penetrating injuries, gunshot wounds, deep depressed skull fractures, stab wounds, or extension of a contusion. Signs and symptoms vary according to the location of the lesion and extent of hemorrhage.

• Secondary Brain Injury

▪ Occurs as a consequence of the initial trauma and is characterized by an inflammatory response and release of cytokines from macrophages that cause increased vascular permeability of the blood vessel wall, leading to vasogenic cerebral edema.▪ Decreased cerebral perfusion from numerous causes, hypoxia, infection, and/or fluid and electrolyte imbalances all contribute to secondary brain injury.▪ Proper management minimizes the effect of secondary brain injury.• Nursing Interventions

• Nonsurgical Interventions

▪ The nonsurgical treatment of a patient with a TBI is the same as for a patient with increased ICP.▪ Emphasis is on reducing ICP, maintaining the airway, providing oxygenation, maintaining cerebral perfusion, and preventing secondary TBI.▪ Therapeutic hypothermia may be implemented to protect the injured brain.Protecting the brain by using hypothermia may improve outcomes in persons with TBI.▪ Nutritional support after TBI is essential. Hypermetabolism, accelerated catabolism, and excess nitrogen losses are responses to TBI.▪ These responses result in depletion of energy stores, loss of lean muscle mass, reduced protein synthesis, loss of GI mucosal integrity, and immune compromise.▪ Nutritional support decreases susceptibility to infections, promotes wound healing, and facilitates weaning from mechanical ventilation.

• Surgical Interventions

▪ A depressed skull fracture may require surgery to elevate and repair or remove bone fragments.▪ Acute subdural hematomas are usually evacuated via burr holes and epidural hematomas via craniotomy to prevent herniation.

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