NR 340 Critical Care Exam 3 Guide

NR 340 Critical Care Exam 3 Guide Neuro Basics • Brain metabolism o Soul source of energy for the brain is glucose. Brain needs glucose to function. Brain cannot store it, but needs a constant supply. If glucose levels start to fall you will some changed. o Cerebral glucose 70 mg/dL = confusion o Cerebral glucose 20 mg/dL = damage • Cerebral blood flow • Autoregulation o Changes in pressure o Changes in CO2 ▪ Alters cerebral blood volume with change in blood vessel size o Ability of the blood vessel in the brain to either constrict or dilate in response to pressure or CO2 levels ▪ Hypotension or hypoventilating causing hypercapnia BV in brain will dilate and vice versa try to send more blood and oxygen to brain. ▪ If hypertension or hypocapnia blood vessels in the brain will constrict. ▪ Systolic less than 50 or greater than 160 BV in brain lose the ability to autoregulate. Neuro Assessment o GCS, LOC, Memory, speech, Reflexes (babinski with brain injury) which only babies should have if adult has it this is not good, motor response, sensation , look for aphasia, motor strength ▪ Concerned with GAS or 8 or lower o Posturing ▪ Decorticate • Extremities go toward the body ▪ Decerebrate • Extremities pull away from the body, more severe, damage to brainstem – this is the worse posturing • Cranial nerves o 1 – Olfactory - Smell o 2 – Optic - vison, pupil response, visual fields – PERRLA - need flashlight or pen light dim the lights in room o 3, 4, 6 - Oculomotor, Trochlear, Abducens - eye movement – 6 fields of gaze “EOM’S” o 5,7 – Trigeminal, Facial - corneal reflex touch patients eyeball, on unresponsive patients- corneal reflex, use gauze or cotton. Touch the eyeball – you want the person to blink as a response. Only do the corneal reflex on someone who is unresponsive. o 8 – Acoustic – hearing - whisper test or just ask the patient questions Just talk to the patient o 9,10 – Glossopharygeal, Vagus – swallow and gag reflex cough and gag – assess gag take a tongue depressor. If patient is intubated use suction to assess gag reflex. o 11 – Accessory – shoulder and neck movement o 12 – Hypoglossal – tongue movement • Oculocephalic Reflex (Doll’s Eyes Reflex) o Usually absent or negative o Only done on unconscious patients when trying to asses brainstem functioning o Not done on if spinal cord injury is present or suspected o Look forward and then move head side to side, ▪ Normal (negative) - eyes will move contralateral (opposite) to the direction the head moves ▪ Irregular (positive) – eyes do not move, stay fixed. (Sign of brain death) • Oculovestibular Reflex (Cold Caloric) o Done on unresponsive patients trying to Asses brainstem functioning. We say its normal or abnormal. o Must have intact tympanic membrane o You need a 50 ml syringe and cool saline ▪ Instill 50ml of cool saline into patients ear ▪ Normal – Eyes will turn toward side you are putting water and go back to center ▪ Abnormal – Eyes do not move (brain death) Intracranial Pressure o Components of ICP: brain tissue, blood, CSF fluid