Increased ICP (939-940, chart 941)
• Normal ICP 10-15 mmHg, pressures >20 mmHg impair cerebral circulation
• IICP is leading cause of death from
... [Show More] head trauma in pts who reach the hospital alive.
• Cerebral Perfusion Pressure (CPP)
o Blood flow required to provide adequate oxygenation & glucose for brain metabolism
o Maintenance above 70 mmHg
o CPP= MAP-ICP
▪ MAP= (2xD) + S MAP NEEDS TO BE ATLEAST 80 3
• Compensation
o First Response – CSF is shunted or displaced into the spine (compliance)
o Next – Reduction of blood volume in the brain (autoregulation)
o As ICP continues to increase cerebral perfusion decreases leading to brain tissue ischemia, edema, vasodilation then acidosis which causes further increases ICP
o In edema remains untreated the brain may herniate into spinal canal – death from brain stem compression
• Assessment Findings
o Changes in LOC – First sign of IICP is declining LOC & includes restlessness or confusion to Stuporous
▪ W/o glucose & 02, brain shuts down. Ex. Pt knew who you were in am & now don’t remember
o Headache – Quite environment may have photophobia so keep room lights very low.
o Change in speech pattern – Aphasia, Slurred Speech
o Changes in pupil size – 2 cm change in either direction is significant, dilated or constricted, Notify Dr
▪ Normal is 6 mm. Getting better if going back toward normal from dilated or constricted
▪ Uneven pupils tx as IICP until proven otherwise; pinpoint - brain stem (pons) dysfunction
o Abnormal Posturing – Decorticate (flexion) or Decerebrate (extensor)
▪ Decorticate – arms drawn to core, legs straight
▪ Decerebrate – arms straight and stiff, pts rarely survive
o Hyperthermia – followed later by hypothermia
▪ When hypothermic – BE CONCERNED, pressure on hypothalamus located next to brain stem
o Cardiac & respiratory rate/rhythm changes
▪ Tachy first – Increased HR & RR before brady HR & RR
o N/V – Common in IICP
o Cushing’s Triad – Severe HTN, Widened Pulse Pressure, Bradycardia
▪ Late response & indicates severe IICP w/loss of autoregulation, Imminent death
▪ Systolic BP increases bc decreased blood flow to brain
▪ Pressure on Vagus nerve and brainstem = bradycardia [Show Less]