Intracranial Pressure & Brain Tumors

Normal ICP

5-15 mmHg

Components within the skull

80% Brain tissue 10% CSF 10% Blood

Osmotic diuretics are an essential intervention for reducing cerebral edema. Which of the following drugs is most frequently prescribed for this situation? A. Mannitol B. Glucose C. Glycerine D. Hypertonic solution

A. Mannitol Rationale: Mannitol is considered the "gold standard" for reducing increased ICP. (p. 1197)

Elevated ICP is most commonly associated with head injury. Which of the following are clinical signs of increased ICP that a nurse should evaluate? Select all that apply. A. Lowered systolic BP B. Respiratory irregularities C. Slow bounding pulse D. Increased cerebral perfusion E. Widened pulse pressure

B, C, and E Rationale: In the early stages of cerebral ischemia, the vasomotor centers are stimulated and the systemic pressure rises to maintain cerebral blood flow. This is typically accompanied by a slow, bounding pulse and respiratory irregularities. These changes in blood pressure, pulse, and respirations are important clinically because they suggest increased ICP. A sympathetically mediated response causes an increase in systolic BP, with a widening of the pulse pressure and cardiac slowing. (p. 1191)

The earliest sign of serious impairment of brain circulation related to increased ICP is: A. A bounding pulse B. Bradycardia C. Hypertension D. A change in consciousness

D. A change in consciousness Rationale: The earliest sign of increasing ICP is a change in LOC. Any changes in LOC should be reported immediately. (p. 1194 - Nursing alert)

Advantages of Subdural/epidural monitors

Easily inserted Low risk of infections No Transducer

Nursing Management for ICP

Glasgow Coma Scale (GCS) Neurologic assessment Motor response & strength assessment Vital signs Respiratory support Seizure precautions Environmental stimuli Temperature control Glycemic control Bowel & Bladder regimens

Conditions causing vasoconstriction

HTN Vasospasms Hyperventilation

Primary Brain Tumors

Localized intracranial lesions that begin in the brain and occupy space within the skull Rarely spread to other areas of the body

Cerebral Perfusion Pressure (CPP) Calculation

MAP - ICP = CPP

TBI patients or pathologic sustained increased ICP may become impaired in patients with:

MI, Resp Failure, shock, sepsis, MODS

Auto regulation of cerebral blood flow (CBF)

Maintains consistent CBF to keep cerebral perfusion pressure within normal limits

Brain tumor nursing management

Monitor for increased ICP Neuro checks Post operative cares (if surgery was performed) Emotional support

Treatment for brain tumors

Surgical intervention Radiation therapy Chemotherapy

Intraventricular Catheter

The most common type of ICP monitoring and it is located in the lateral ventricle on the nondominant side, it is very accurate but it must be kept level with the foramen of Monro (middle of the ear) for an accurate reading.

Changes in CBF/CPP can occur from:

Vasoconstriction Vasodilation

A patient with a head injury is being assessed for altered LOC and increased ICP. The patient's last ICP reading was 16 mmHG. The nurse understands that treatment for increased ICP will be initiated at a pressure greater than: a. 18 mmHg b. 19 mmHg c. 20 mmHg d. 21 mmHg

c. 20 mmHg Rationale: ICP is usually measured in the lateral ventricles, with normal pressure being 5-10 mmHg. Treatment of ICP is generally initiated at a pressure greater than 20 mmHg. (p. 1190)

Signs of Increasing ICP

•LOC worsens until patient becomes comatose if untreated •Respiratory rate decreases •BP and Temp increase •Pulse fluctuates bradycardia to tachycardia •Projective vomiting may occur •Posturing develops as pressure on brain stem increases •Loss of reflexes (swallowing, pupillary, gag) indicated impending death

Advantages of Intraventricular catheters (IVC)

Accurate Reliable measures of ICP Can withdraw CSF

Ventriculostomy advantages:

Best for accurate monitoring Continuous monitoring and drainage of the build-up of CSF Testing can be done

Which of the following is a clinical manifestation of pupillary changes that indicate increasing ICP? A. Pupils are equal and normally reactive B. Pupils are unequal in diameter C. Pupils are showing progressive dilation D. Pupils are fixed and dilated

C. Pupils are showing progressive dilation Rationale: Pupils that show progressive dilation are indicative of increasing intracranial pressure. (Table 45-1 on p. 1193)

Diagnostic studies for ICP

CT MRI

Cushing's Response (or Reflex)

Cerebral bloodflow decreases significantly: When ischemic, vasomotor center triggers an increases in arterial pressure in an effort to overcome ICP. Sympathetic response causes increase in systolic BP, with widening of pulse pressure and cardiac slowing.

Changes in volume of brain tissue can occur from:

Cerebral edema Mass effect

Leading cause of secondary brain injury

Cerebral edema (brain swelling) - Abnormal accumulation of water or fluid in the intracellular space As tissue expands blood flow decreases leading to ischemia and tissue death. Brain tissue swells and may herniate into other compartments or compress other vital brain areas

Early signs of increased ICP

Changes in LOC - restlessness, increased respiratory effort, confusion Pupillary changes Weakness in one extremity or one side Constant headache

Late stages of increased ICP

Decreasing LOC Change in vital signs Altered respiratory pattern - Cheyne Stokes Projectile Vomiting Hemiplegia OR decorticate OR decerebrate posturing Loss of brainstem reflexes

Monroe-Kellie hypothesis

Due to limited space for expansion within the skull, an increase in volume of any one of the cranial contents - brain tissue, blood, or CSF - must be compensated for by a decrease in volume of another.

Advantages of fiberoptic monitors

Easily inserted No adjustment of the transducer with head movement It provides accurate measurements Not blocked by tissue debris or blood clots. Not blocked by brain swelling or herniation. Does not require patient's head to be placed in any particular position and thus, allows for easy transportation of the patient. Can be used in situations where the ventricles are narrowed from brain swelling or a tumor.

Conditions causing vasodilation

Hypercarbia Hypoxemia Acidosis

Pharmacologic treatment for ICP

Hypertonic Saline Mannitol Analgesics Sedatives Paralytics

Vasoconstriction

Increased MAP Decreased CPP

Vasodilation

Increases ICP Decreases CPP

Nursing Diagnoses for ICP

Ineffective cerebral tissue perfusion Altered tissue perfusion Sensory perceptual alteration Impaired physical mobility

Disadvantages of fiberoptic monitors

Invasive. Cannot be used to sample or drain CSF. Cannot be recalibrated after insertion and accuracy diminishes over time. Expensive. There may be damage to the fragile fiber-optic cables which will lead to inaccurate measurements. Risk of bleeding.

Diagnostics for brain tumors

MRI CT Positron emission tomography Biopsy

Secondary Brain Tumor

Metastasis from cancer elsewhere in the body Common sites - lungs, breast, kidney, colon, pancr

Changes in CSF can occur from:

Overproduction of CSF Inadequate CSF reabsorption Blockage of CSF circulation

Advantages of subarachnoid monitors

Simple single readings No penetration of brain tissue Can sample CSF Direct pressure management

Benign brain tumors

Slow growing but can occur in a vital area, where they can grow large enough to cause serious effects

Ventriculostomy disadvantages:

Surgically implanted into the ventricle Infection Meningitis Ventricular Collapse Occlusion of the catheter- tissue or blood Monitor issues or misinformation

Cushing's Triad

A grave sign with symptoms including: Bradypnea Bradycardia Hypertension

Manifestations of brain tumors

Headache Personality changes Fatigue Increased Nausea Vomiting Visual disturbances Seizures

Nursing management focuses on detecting early signs of increased ICP because interventions are usually ineffective once late signs appear

Headache that is constant, increased in intensity and aggravated by movement or straining

Cerebral Perfusion Pressure (CPP)

Normal 60 - 100 mm Hg

Disadvantages of subarachnoid monitors

Not very accurate as compared to the intraventricular or intraparenchymal monitors Can be blocked by tissue debris and brain swelling Needs to recalibrated frequently Risk of bleeding

Disadvantages of subdural/epidural monitors

OR for placement Unable to recalibrate once device is placed

Primary Injury

Occurs at the time of initial injury - resulting in displacement, bruising, or damage of any of the 3 components of the skull

Secondary Injury

Occurs hours to days after initial injury - resulting in hypoxia, ischemia, hypotension, edema, or increased ICP

Intracranial Pressure (ICP)

Pressure in the cranial vault relative to atmospheric pressure

Risk factors for brain cancer

Radiation exposure Cancer-causing chemicals Physical and acoustic trauma Dietary factors

Malignant brain tumors

Rapidly growing, can spread into surrounding tissue and considered life-threatening

Hypothermia for ICP Patients

Recommended for fulminant hepatic failure patients that has led to cerebral edema Difficulty cooling the patient adequately Control of fever is essential

Decompressive craniectomy for ICP Patients

Reduces ICP surgically by the removal of the rigid skull Widely used

Complications of ICP Monitoring

Relatively low risk considering the alternate options Risks outweigh the benefit Bleeding and Infection Rebound swelling Placement or dislodging- need special care!

Nursing Implementation for ICP Patients

Respiratory function - intubation & mechanical ventilation Fluid & electrolyte balance Monitoring ICP Body position - elevate HOB to 30 degrees Protection from injury Psychological considerations

Disadvantages of Intraventricular catheters (IVC)

Risk for infection, edema, and bleeding

Mass Effect:

The result of increased intracranial pressure of any cause (e.g., brain tumor, blockage of CSF or accumulation of CSF in cranial cavity) which, in the non-distensible cranial cavity, acts like a mass.