# Levels of Consciousness --- **Levels of consciousness** or **LOC** are measurements of a person's arousability and their responsiveness to stimuli. ' Brain function deterioration follows predictable rostal to caudal progression (loss of higher function, then loss of more primitive functions) A. B. Aware of self and the environment and is able to respond appropriately to stimuli Requires: Arousal (alertness) (in the reticular activating system in thalamus) 2. Cognition (ability to process thoughts, problem solve (in the cerebral hemispheres) Altered LOC l. 2. 3. Variety of labels (stupor, confusion, semi-comatose, coma: a variety of levels; something difficult to judge Not standardized Better to report behavior and response to stimuli than to label; use Glasgow Coma Scale: Eye Opening, Motor, Verbal responses S/S pupils Brain lesion localized = ipsilateral pupil affected (same side) Brain lesion generalized (both cerebral hemispheres) = both pupils affected Progressive functional impairment = pupils unrepsonsive to light (fixed and dilated) VERY omonous sign oculumotor function Normally both eyes move simultaneously in same direction With decreasing LOC spontaneous movement lost; reflexes may still be intact • "Doll's eyes movement" (indicator of brain stem function (see next slide) indicator of [[brainstem]] function we want to see it. when you take someone with low LOC and turn their head left, the eyes will automacally move right, and vice versa this is one of the last tests you do before you start looking at brain death Another eye reflex: Eyes move up with passive flexion of neck & down with passive neck extension ' This reflex also lost with further deterioration OCCULOVESTIBULAR RESPONSE Cold water into the ear canal (aka cold caloric testing) Normal causes nystagmus (lateral deviation of eyes) toward stimulus Reflex lost with brain function deterioration MOTOR Response Most Accurate identifier of changes in mental status ' Both the level of brain dysfunction and the side of the brain affected can be assessed ' Ranges from obeying to flaccidity At first purposeful movement = brush away noxious stimuli As LOC decreases = less purposeful (may just withdraw or grimace Central Stimulation: painful stimuli to central portion: Trapezius pinch, sternal rub, orbital pressure (brain) • Peripheral Stimulation: Nail bed pressure (spinal cord) A. Decorticate posturing l. 2. 3. Indicates lesions of the Corticospinal tract (Descending motor paths that originate in motor cortex of brain then messages to brain stem and then to spinal cord) Flexion of upper extremities Extension of lower extremities Decerebrate posturing ---way worse B. Indicates lesion of midbrain, pons, l. diencephalon 2. Usually worse sign than decorticate; further deterioration 3. Adduction and rigid extension of upper and lower extremities Finally, if no intervention, flaccid with little or no motor response to stimuli BREATHING Normal respiration = very regular pattern With damage to nervous system, irregular respiratory patterns may develop Cheyne-Stokes Cluster breathing - **Alert**: At this level someone is awake, easily aroused, orientated and fully aware of their surroundings. - **Lethargic** (sometimes called **somnolent**): At this level someone isn't fully alert—they may fall asleep if not stimulated, but they are easily aroused. They may have slowed thinking, but are able to answer questions. This may be very concerning in [[pediatrics]], as it's abnormal for children to be lethargic. - **Obtunded** (noun: *obtundation*): At this level someone is mostly asleep, and cannot be fully aroused. They open their eyes to the sound of voices, but seem confused and unaware of their environment. They tend to sleep more than normal and are drowsy between sleep states. - **Stupor** or **semi-coma**: At this level someone is unconscious, and responds only to vigorous and repeated stimuli. They withdraw appropriately to pain, but will return to unresponsive sleep left undisturbed. - **Coma**: At this level a person is completely unconscious. They are unarousable and do not respond to pain. [[persistent vegetative state]] [[locked-in syndrome]] [[brain death]] ## The Glasgow Coma Scale The **Glasgow Coma Scale** is a commonly used assessment tool for ratings someone's response to stimulus. The higher the number the more conscious one is. At a score of 10 or lower a person should receive emergency attention, and a 7 or lower is generally considered to be in a coma. "gcs less than 8 get ready to intubate" ![[glasgow coma scale.png]] ## AVPU What is the patient alert to? **Alert** Fully awake (although not necessarily oriented). This patient will have spontaneously open eyes, will respond to voice (although may be confused) and will have bodily motor function. **Verbal**: The patient makes some kind of response when you talk to them, which could be in any of the three component measures of eyes, voice or motor - patient's eyes open on being asked "Are you 0K?". The response could be as little as a grunt, moan, or slight move of a limb when prompted by the voice of the rescuer. **Pain**: The patient makes a response on any of the three component measures on the application of pain stimulus, such as a central pain stimulus like a sternal rub or a peripheral stimulus such as squeezing the fingers. A patient with some level of consciousness (a fully conscious patient would not require a pain stimulus) may respond by using their voice, moving their eyes, or moving part of their body (including abnormal posturinq). Decordacate vs cerabate **Unresponsive**: Sometimes seen noted as 'unconscious', this outcome is recorded if the patient does not give any eye, voice or motor response to voice or pain. ___