NURSING PROCESS: THE PATIENT WITH INCREASED ICP
Initial assessment of the patient with increased ICP includes ob-taining a history of events leading to the present illness and other subjective data; it may be necessary to obtain this information from family or friends. The neurologic examination should be as complete as the patient’s condition allows. It includes an evaluation of mental status, LOC, cranial nerve function, cerebellar function (balance and coordination), reflexes, and motor and sensory func-tion. Because the patient is critically ill, ongoing assessment willbe more focused, including pupil checks, assessment of selected cranial nerves, frequent measurements of vital signs and intra-cranial pressure, and use of the Glasgow Coma Scale. Assessment of the patient with altered LOC is summarized in Table 61-1.
Based on the assessment data, the major nursing diagnoses for pa-tients with increased ICP include the following:
· Ineffective airway clearance related to diminished protective reflexes (cough, gag)
· Ineffective breathing patterns related to neurologic dys-function (brain stem compression, structural displacement)
· Ineffective cerebral tissue perfusion related to the effects of increased ICP
· Deficient fluid volume related to fluid restriction
· Risk for infection related to ICP monitoring system (fiberoptic or intraventricular catheter)
Other relevant nursing diagnoses are included in the section on caring for patients with altered LOC.
Based on the assessment data, potential complications include:
· Brain stem herniation
· Diabetes insipidus
The goals for the patient include maintenance of a patent airway, normalization of respiration, adequate cerebral tissue perfusion through reduction in ICP, restoration of fluid balance, absence of infection, and absence of complications.
The patency of the airway is assessed. Secretions obstructing the airway must be suctioned with care, because transient elevations of ICP occur with suctioning (Hickey, 2003). The patient is hy-peroxygenated before and after suctioning to maintain adequate oxygenation. Hypoxia caused by poor oxygenation leads to cere-bral ischemia and edema. Coughing is discouraged because coughing and straining also increase ICP. The lung fields are aus-cultated at least every 8 hours to determine the presence of ad-ventitious sounds or any areas of congestion. Elevating the head of the bed may aid in clearing secretions as well as improving ve-nous drainage of the brain.
The patient must be monitored constantly for respiratory irreg-ularities. Increased pressure on the frontal lobes or deep midline structures may result in Cheyne-Stokes respirations, whereas pressure in the midbrain may cause hyperventilation. When the lower portion of the brain stem (the pons and medulla) is in-volved, respirations become irregular and eventually cease.
If hyperventilation therapy is deemed appropriate to reduce ICP (by causing cerebral vasoconstriction and a decrease in cere-bral blood volume), the nurse collaborates with the respiratory therapist in monitoring PaCO2, which is usually maintained at 35 to 45 mm Hg (Hickey, 2003).
A neurologic observation record (Fig. 61-5) is maintained, and all observations are made in relation to the patient’s baseline condition. Repeated assessments of the patient are made (some-times minute by minute) so that improvement or deterioration may be noted immediately. If the patient’s condition deteriorates, preparations are made for surgical intervention.
In addition to ongoing nursing assessment, strategies are initi-ated to reduce factors contributing to the elevation of ICP (Table 61-2).
Proper positioning helps to reduce ICP. The head is kept in a neutral (midline) position, maintained with the use of a cervi-cal collar if necessary, to promote venous drainage. Elevation of the head is maintained at 0 to 60 degrees to aid in venous drainage unless otherwise prescribed (Sullivan, 2000). Extreme rotation of the neck and flexion of the neck are avoided because compression or distortion of the jugular veins increases ICP. Ex-treme hip flexion is also avoided because this position causes an increase in intra-abdominal and intrathoracic pressures, which can produce a rise in ICP. Relatively minor changes in position may significantly affect ICP (Sullivan, 2000). If monitoring pa-rameters demonstrate that turning the patient raises ICP, rotat-ing beds, turning sheets, and holding the patient’s head during turning may minimize the stimuli that increase ICP.
The Valsalva maneuver, which can be produced by straining at defecation or even moving in bed, raises ICP and is to be avoided. Stool softeners may be prescribed. If the patient is alert and able to eat, a diet high in fiber may be indicated. Abdominal disten-tion, which increases intra-abdominal and intrathoracic pressure and ICP, should be noted. Enemas and cathartics are avoided if possible. When moving or being turned in bed, the patient can be instructed to exhale (which opens the glottis) to avoid the Valsalva maneuver.
Mechanical ventilation presents unique problems for the pa-tient with increased ICP. Before suctioning, the patient should be preoxygenated and hyperventilated using 100% oxygen on the ventilator (Hickey, 2003). Suctioning should not last longer than 15 seconds. High levels of positive end-expiratory pressure are avoided because they may decrease venous return to the heart and decrease venous drainage from the brain through increased intra-thoracic pressure (Hickey, 2003).
Activities that raise ICP, as indicated by changes in wave-forms, should be avoided if possible. Spacing nursing interven-tions may prevent transient increases in ICP. During nursing interventions, the ICP should not rise above 25 mm Hg and should return to baseline levels within 5 minutes. Patients with increased ICP should not demonstrate a significant increase in pressure or change in the ICP waveform. Patients with the po-tential for a significant increase in ICP should receive sedation or “paralyzation” before initiation of many nursing activities (Hickey, 2003; McConnell, 2001).
Emotional stress and frequent arousal from sleep are avoided. A calm atmosphere is maintained. Environmental stimuli (noise, conversation) should be minimal. Isometric muscle contractions are also contraindicated because they raise the systemic blood pressure and hence the ICP.
The administration of various osmotic and loop diuretics is part of the treatment protocol to reduce ICP. Corticosteroids are used to reduce cerebral edema, and fluids may be restricted. All of these treatment modalities promote dehydration.
Skin turgor, mucous membranes, and serum and urine os-molality are monitored to assess fluid status. If fluids are given intravenously, the nurse ensures they are administered at a slow to moderate rate with an intravenous infusion pump to prevent too-rapid administration and avoid overhydration. For the patient receiving mannitol, the nurse observes for the possible development of heart failure and pulmonary edema, because the intent of treatment is for fluid to shift from the intracellular compartment to the intravascular system, thus controlling cere-bral edema.
For patients undergoing dehydrating procedures, vital signs, including blood pressure, must be monitored to assess fluid vol-ume status. An indwelling urinary catheter is inserted to permit assessment of renal function and fluid status. During the acute phase, urine output should be monitored every hour. An output greater than 200 mL/hr for 2 consecutive hours may indicate the onset of diabetes insipidus (Cruz, 1998). These patients also need careful oral hygiene because mouth dryness is associated with de-hydration. Frequently rinsing the mouth, lubricating the lips, and removing encrustations relieve dryness and promote comfort.
Risk for infection is greatest when ICP is monitored with an in-traventricular catheter. Most health care facilities have written protocols for managing these systems and maintaining their sterility; strict adherence to them is essential.
The dressing over the ventricular catheter must be kept dry be-cause a wet dressing is conducive to bacterial growth. Aseptic technique must be used when managing the system and changing the ventricular drainage bag. The drainage system is also checkedfor loose connections because they cause leakage and contamina-tion of the CSF as well as inaccurate readings of ICP. The nurse should observe the character of the CSF drainage and report ob-servations of increasing cloudiness or blood. The patient is mon-itored for signs and symptoms of meningitis: fever, chills, nuchal (neck) rigidity, and increasing or persisting headache.
The primary complication of increased ICP is brain herniation resulting in death (see Fig. 61-2). Nursing management focuses on detecting early signs of increasing ICP because medical inter-ventions are usually ineffective once later signs develop. Frequent neurologic assessment and documentation and analysis of trends will reveal the subtle changes that may herald rising ICP.
The nurse assesses for and immediately reports any of the fol-lowing early signs or symptoms of increasing ICP:
· Disorientation, restlessness, increased respiratory effort, pur-poseless movements, and mental confusion; these are early clinical indications of rising ICP because the brain cells re-sponsible for cognition are extremely sensitive to decreased oxygenation
· Pupillary changes and impaired extraocular movements; these occur as the increasing pressure displaces the brain against the oculomotor and optic nerves (cranial nerves II, III, IV, and VI) arising from the midbrain and brain stem
· Weakness in one extremity or on one side of the body; this occurs as increasing ICP compresses the pyramidal tracts
· Headache that is constant, increasing in intensity, and ag-gravated by movement or straining; this occurs as increasing ICP causes pressure and stretching of venous and arterial vessels in the base of the brain
As ICP rises, the patient’s condition worsens, as manifested by the following later signs and symptoms:
· LOC continues to deteriorate until the patient is comatose.
· The pulse rate and respiratory rate decrease or become er-ratic, and the blood pressure and temperature rise. The pulse pressure (the difference between the systolic and the diastolic pressures) widens. The pulse fluctuates rapidly, varying from bradycardia to tachycardia.
· Altered respiratory patterns develop, including Cheyne-Stokes breathing (rhythmic waxing and waning of rate and depth of respirations alternating with brief periods of apnea) and ataxic breathing (irregular breathing with a random se-quence of deep and shallow breaths).
· Projectile vomiting may occur with increased pressure on the reflex center in the medulla.
· Hemiplegia or decorticate or decerebrate posturing may de-velop as pressure on the brain stem increases. Bilateral flac-cidity occurs before death.
· Loss of brain stem reflexes, including pupillary, corneal, gag, and swallowing reflexes, is an ominous sign.
Because clinical assessment is not always a reliable guide in rec-ognizing increased ICP, especially in comatose patients, ICP mon-itoring is an essential part of management (Hickey, 2003). ICP is monitored closely for continuous elevation or significant increase over baseline. The trend of ICP measurements over time is an im-portant indication of the patient’s underlying status. Vital signs are assessed when the increase in ICP is noted.
Strict aseptic technique is used when handling any part of the monitoring system. The insertion site is inspected for signs of infection. Temperature, pulse, and respirations are closely mon-itored for systemic signs of infection. All connections and stop-cocks are checked for leaks, because even small leaks can distort pressure readings.
When ICP is monitored with a fluid system, the transducer is calibrated at a particular reference point, usually 2.5 cm (1 in) above the ear with the patient in the supine position; this point corresponds to the level of the foramen of Monro (Fig. 61-6). (CSF pressure readings depend on the patient’s position.) For subsequent pressure readings, the head should be in the same po-sition relative to the transducer. Fiberoptic catheters are cali-brated before insertion and do not require further referencing; they do not require the head of the bed to be at a specific position to obtain an accurate reading.
Whenever technology is associated with patient management, the nurse must be certain that the technology is functioning prop-erly. The most important concern, however, must be the patient who is attached to the technology. The patient and family must be informed about the technology and the goals of its use. The pa-tient’s response is monitored and appropriate comfort measures are implemented to ensure that the patient’s stress is minimized.
ICP measurement is only one parameter: repeated neurologic checks and clinical examinations remain important measures. As tute observation, comparison of findings with previous observa-tions, and interventions can assist in preventing life-threatening ICP elevations.
The nurse also assesses for complications of increased ICP, in-cluding diabetes insipidus and SIADH (see Chaps. 14 and 42). Urine output should be monitored closely. Diabetes insipidus re-quires fluid and electrolyte replacement, along with the adminis-tration of vasopressin, to replace and slow the urine output. Serum electrolyte levels should be monitored for imbalances. SIADH re-quires fluid restriction and monitoring of serum electrolyte levels.
Expected patient outcomes may include:
1) Maintains patent airway
2) Attains optimal breathing pattern
a) Breathes in a regular pattern
b) Attains or maintains arterial blood gas values within acceptable range
3) Demonstrates optimal cerebral tissue perfusion
a) Increasingly oriented to time, place, and person
b) Follows verbal commands; answers questions correctly
4) Attains desired fluid balance
a) Maintains fluid restriction
b) Demonstrates serum and urine osmolality values within acceptable range
5) Has no signs or symptoms of infection
a) Has no fever
b) Shows no signs of infection at arterial, intravenous, and urinary catheter sites
c) Has no purulent drainage from invasive intracranial monitoring device
6) Absence of complications
a) Has ICP values that remain within normal limits
b) Demonstrates urine output and serum electrolyte levels within acceptable limits
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