Head Injury, Cranial Surgery and IICP

1. Head Injury, Cranial Surgery and IICP NUR 2549

2. Unconsciousness • An abnormal state in which client is unaware of self or environment • Can be for very short time to long term coma • Care is designed to • Determine the cause • Maintain bodily functions • Support vital functions • Protect client from injury

3. Etiology • Arousal • State of being awake that depends on a group of neurons in the brainstem • Can maintain level of wakefulness even without functioning cortex

4. From Human Physiology RAS is located in brain stem

5. Etiology • Content part of consciousness • Ability to reason, think and feel • Also to react to stimulus with purpose and awareness • Controlled by cerebral hemispheres (higher centers) • Intellect and emotional function are also controlled in the same area.

7. Major Reactions • Two reactions affecting cerebral metabolism occur: • Cerebral ischemia /anoxia – brain isn’t getting enough oxygen and compensatory mechanisms take place • Cerebral edema results because the brain compensates by dilating blood vessels trying to get more oxygen

8. Behavior • Document accurately what the client’s behavior is. Example: if the client opens eyes on command but not spontaneously, chart it as such. Be descriptive.

9. Glascow Coma Scale • Used to document assessment in three areas • Eyes • Verbal response • Motor response • Normal is 15 and less than 8 indicates coma

10. From Rehabilitation Nursing

11. From Rehabilitation Nursing

12. Other Assessment • Assess bodily function including respiratory, circulatory and elimination • Pupil checks – are pupils equal and how they react to light • Extremity strength • Corneal reflex test

13. Intracranial Pressure • Monro-Kellie hypothesis (applies only to children with a rigid skull and not neonates) • Skull is an enclosed space with three variables • Brain tissue • Blood • Cerebrospinal fluid

14. Intracranial Pressure • The skull cannot expand to allow for extra space occupying tissue or fluid • If one of the three components increases the other two must decrease in order to compensate

15. Intracranial Pressure • Other factors that influence intracranial pressure • Arterial pressure • Venous pressure • Intraabdominal and intrathoracic pressure • Posture • Temperature • Blood gases (left off handout)

16. Normal Intracranial Pressure • Pressure exerted by total volume from: • Brain tissue • Blood • Cerebrospinal fluid • Normal manometer reading – 80-180 • Normal transducer reading – 0-15mm Hg

17. Cerebral Blood Flow • Amount of blood going through 100g of brain tissue in 1 minute – cerebral blood flow is 50ml/min per 100g • Brain uses 20% of the body’s oxygen • Brain uses 25% of body’s glucose

18. Autoregulation of Cerebral Blood Flow • Blood vessels alter their diameter to ensure a constant cerebral blood flow • Lower limit for MAP is 50mm Hg. • Below this, cerebral flow decreases and there is risk of ischemia • Upper limit is MAP of 150mmHg. Above this the cerebral blood vessels are maximally constricted. Blood vessels cannot constrict more to control high pressure. Blood brain barrier is disrupted and cerebral edema and ICP results • MAP= DBP + 1/3 Pulse Pressure

19. Cerebral Perfusion Pressure (CPP) • Pressure needed to maintain blood flow to the brain • MAP-ICP=CPP • Normal CPP is 60-100 • CPP>100 is hyperperfusion and IICP • CPP< 60 hypoperfusion • CPP<30 incompatible with life

20. Elastance – stiffness of the brain • High elasticity –high elastance ICP increases with small increases in volume • Low elasticity – brain compensates and ICP stays stable

21. Compliance • Low compliance is same as high elastance • High compliance – ICP remains stable • Blood pressure • If MAP is low, blood vessels in brain dilate to bring in more blood • If MAP is high, blood vessels constrict to shunt away blood from brain

22. Metabolic Factors affecting cerebral blood flow • Oxygen tension – When oxygen tension (PaO2) falls below 50, cerebral arteries dilate to increase cerebral blood flow. If this fails to happen, the brain metabolism changes to anaerobic metabolism and lactic acid builds up • Carbon dioxide tension - If the blood becomes acidic, the blood vessels dilate to increase cerebral blood flow (increased CO2 and acidosis are potent vasodilators)

23. Metabolic Factors • Globally • extreme cardiovascular changes (asystole) • Pathophysiologic states (diabetic coma) • Focally • Trauma and tumors

24. Stages of Increased ICP • Stage 1 – High compliance and low elastance. Autoregulation is functioning • Stage 2 – Compliance is lower and elastance is increased. An increase in volume places client at risk for IICP • Stage 3 – High elastance and low compliance. Small changes in volume will cause large increase in ICP

25. Stages of Increased ICP • Stage 4 – ICP rises to terminal levels with little increase in volume. Brain herniates leading to • REST IN PEACE

26. Increased Intracranial Pressure • From an increase in cranial volume that results from increase in one or more of the following: • Brain tissue • Blood • Cerebrospinal fluid

27. Cerebral edema – regardless of cause, increases tissue volume, can lead to IICP Types – Vasogenic-most common (tumors, abscesses, ingested toxins) Cytotoxic-local disruption of cell membranes (lesions or trauma) Interstitial-uncontrolled hydrocephalus, hyponatremia Increased Intracranial Pressure

28. Complications of IICP • Inadequate cerebral perfusion • Cerebral herniation • Brain shift : Lateral, downward, or both • Irreversible • Edema and ischemia further increased • Compression of brainstem and cranial nerves may be fatal • Cerebellum and brainstem forced through foramen magnum

29. Clinical Manifestations • Change in level of consciousness is the most sensitive and important indicator of neuro status • May be pronounced or subtle • Early signs may be nonspecific: restlessness, irritability, generalized lethargy

30. Clinical Manifestations • Changes in vital signs-this is ominous sign • This is a late sign – Cushing’s triad • Increasing systolic blood pressure • Pulse slowing and is bounding • Irregular respiratory pattern • May also have a change in temperature

31. Clinical Manifestations • Ocular signs • Pupil changes are from pressure on third cranial nerve • Pupils become sluggish, unequal. This is because of brain shift. May also be pressure on other cranial nerves

32. Clinical Manifestations • Decrease in motor function • May have hemiparesis or hemiplegia • May see posturing – either decorticate or decerebrate • Decerebrate – more serious from damage in midbrain and brainstem • Decorticate – from interruption of voluntary motor tracts

33. Clinical Manifestations • Headache • From compression on the walls of cranial nerves, arteries and veins • Worse in the morning • Straining and movement makes worse

34. Clinical Manifestations • Vomiting • NOT preceded by nausea- “unexpected” • May be projectile

35. Diagnostic Tests • CT • MRI • Cerebral angiography • EEG • PET • No lumbar puncture if there is ICP because sudden release of pressure can cause brain to herniate • ABG’s – keep O2 at 100% (Lewis 1615) and PCO2 as related to ICP (25-35)

36. Drug Therapy • Mannitol – Rapid short acting diuretic that decreases ICP. Decreases total brain water content • Watch fluids and electrolytes closely (I and O and labs) • Don’t give in cases of renal failure or if serum osmolality increased

37. Drug Therapy • Loop diuretics – reduce blood volume and tissue volume • Corticosteroids – Decadron most common steroid used. Watch for side effects. Should be on antacids or H2 receptor blockers to prevent ulcers.

38. Drug Therapy • Barbiturates – causes decrease in metabolism and ICP. Causes reduction in cerebral edema and blood flow to brain. • Watch for hangover effects and drowsiness. Side effects make it harder to check LOC. Watch for constipation – do not want client straining. Skeletal muscle paralyzers may be used (Pavulon) Antiseizure drugs - Dilantin

39. Nutrition • Clients need higher amounts of glucose to survive. • Will need nutritional support quickly. • Watch sodium if on Mannitol – may need to give additional salt. • Also may need additional free water if dehydrated – watch I and O closely. • Give low CHO diet to help with CO2

40. Nutrition • Fluid balance is controversial • Do not want too dry • Keep normavolemic • Give saline either .45% or normal saline – not glucose to help prevent additional cerebral edema

41. Laboratory Work • ABGs regularly • Electrolytes daily

42. Nursing Interventions • Airway and respiratory – suction only as needed and for 10 seconds at a time, only 2 passes. Give 100% O2 prior to suctioning. • Avoid abdominal distention – may need NG tube to decompress stomach • Sedate with care – if not on a vent, use sedation that will not interfere with respiration or mask any neuro changes

43. Nursing Interventions • Keep HOB elevated 30 degrees if BP is normal • If BP is low will need to put HOB flat • Keep head in alignment to prevent cutting off venous flow from the head • Don’t elevate knees – this will increase intrathoracic pressure • Turn gently from side to side – if turning raises ICP, client will need to stay on back

44. Nursing Interventions • If client is posturing frequently during care, will need to sedate first and then do only one thing at a time. Minimize stimulation • These clients can become agitated and combative – avoid over stimulating them • Restraining them will make them MORE AGITATED and RAISE THEIR ICP!

45. Nursing Interventions • Use minimal stimulation – perhaps one family member that is particularly calming – not the entire neighborhood can stay with client • Use a calm voice when talking to the client • Calmly tell the client what you are going to do when providing care • NO TV IN ROOM • Keep room darkened if needed

46. Nursing Interventions • Keep body temperature within normal limits • Give ordered PRN antipyretics (probably Tylenol) • May need to use cooling blanket • Do not use ice on client

47. Nursing Interventions • Hygiene – keep skin clean and dry. Watch for skin breakdown • May need to be on a special bed • Keep mouth clean and moist • May need eye drops to moisten eyes • Families need a lot of support even after client leaves ICU • Client may benefit from rehab to help him adapt and progress

48. Nursing Interventions • Prevent infection • Protect from injury • Avoid factors that increase ICP • Psychological support

49. Pediatric Considerations • Open fontanels allow expansion of skull • Neuro changes may be harder to detect because child cannot communicate as well • Cushing’s triad rarely seen in children • Compare child’s behavior with their developmental level

50. Pediatric Considerations • Assess for developmental differences and physical anomalies • Is child appropriate for age? • Look for physical injuries such as bites, bruises • Use special Glascow coma scale for child