INTRACRANIAL PRESSURE

1. INTRACRANIAL PRESSURE

2. Intracranial Pressure • Refers to the pressure contained within the cranial cavity. • The normal range is between 0 to 15 mmHg. • ICP over 20 mm/Hg is considered elevated ICP, also known as intracranial hypertension. • The management team becomes concerned whenever a patient’s ICP is over 15 mm/Hg, but is especially concerned when it reaches levels of intracranial hypertension.

3. Intracranial Pressure • Skull has three essential components: - Brain tissue = 78% - Blood = 12% - Cerebrospinal fluid (CSF) = 10% • Any increase in any of these tissues causes increased ICP

4. Components of the Brain Fig. 55-1

5. Factors that influence ICP • Arterial pressure • Venous pressure • Intraabdominal and intrathoracic pressure • Posture • Temperature • Blood gases (CO2 levels)

6. Intracranial Pressure • The degree to which these factors  ICP depends on the ability of the brain to accommodate to the changes

7. Regulation and Maintenance for ICP • If the volume in any one of the components (brain tissue, blood, and CSF) • increases within the cranial vault and the volume from another component is displaced, the total intracranial volume will not change

8. Intracranial PressureRegulation and Maintenance • Normal compensatory adaptations • Alteration of CSF absorption or production • Shunting of CSF into spinal subarachnoid space • Shunting of venous blood out of the skull

9. Mechanisms of Increased ICP • Causes • Mass lesion • Cerebral edema • Head injury • Brain inflammation • Metabolic insult

10. Increased Intracranial PressureMechanisms of Increased ICP • Sustained increases in ICP result in brainstem compression and herniation of the brain from one compartment to another

11. Increased Intracranial Pressure Fig. 55-3

12. Herniation Fig. 55-4

13. SITES FOR ICP MONITORINGEpiduralSubarachnoidIntraventricular

14. ICP mentoring system

15. ICP mentoring system

16. Nursing Care: Assessment • Change in level of consciousness • Changes in vital signs (Cushing triad) • Widening pulse pressure • Tachy/Bradycardia • Increased systolic BP • Irregular respirations

17. Nursing Care: Assessment • Ocular signs • Decrease in motor strength and function • Assess movement • Assess response to stimuli • Assess: • Decerebrate posturing (extensor) • Indicates more serious damage • Decorticate posturing (flexor)

18. Decorticate and Decerebrate Posturing

19. Nursing Care: Assessment • Headache • Often continuous and worse in the morning • Vomiting • Not preceded by nausea • Projectile

20. Increased Intracranial PressureCollaborative Care • Hyperventilation therapy: suctioning → hyperventilate with 100% oxygen • Adequate oxygenation • PaO2 maintenance at 100 mm Hg or greater • ABG analysis guides the oxygen therapy • May require mechanical ventilator

21. Increased Intracranial PressureCollaborative Care • Drug therapy • Mannitol • Loop diuretics • Corticosteroids • Barbiturates • Antiseizure drugs

22. Increased Intracranial PressureCollaborative Care • Nutritional therapy • Patient is in hypermetabolic and hypercatabolic state •  Need for glucose • Keep patient normovolemic • IV 0.45% or 0.9% sodium chloride

23. Increased Intracranial PressureNursing Management Overall goals: • ICP WNL • Maintain patent airway • Normal fluid and electrolyte balance • No complications secondary to immobility • Respiratory function • Fluid and electrolyte balance

24. Increased Intracranial PressureNursing Management Overall goals (cont’d) • Body position maintained in head-up position: elevate HOB 30° • Protection from injury: positioning/turning • Pain control • Psychological considerations