Care of Patient With Coma

1. Care of Patient With Coma Dr. BelalHijji, RN, PhD November 12, 2011

2. Learning Outcomes At the end of this lecture, students will be able to: • Describe what coma is, identify its causes, and discuss its pathophysiology. • Discuss assessment and clinical diagnosis of coma and vegetative state. • Describe the medical and nursing management of coma.

3. Description of Coma and its Causes • Normal consciousness requires awareness (cognition and affect) and arousal. Deficits in awareness, arousal, or both may result in altered consciousness. • In coma, a patient is in the deepest state of unconsciousness; awareness and arousal are lacking. • Coma is a symptom not a disease; its causes are structural (ischemic stroke, intracerebral hemorrhage, trauma, and brain tumors) and metabolic (as in the case of drug overdose, infectious disease, endocrine disorders, and poisoning).

4. Pathophysiology of Coma

5. Ascending fibers of the reticular activating system (ARAS) in the pons (contains respiratory centre; connects spinal cord with brain & parts of brain with each other) , hypothalamus (Reception of sensory impulses from viscera, control of body temperature) and thalamus (relay station for nearly all sensory impulses) are responsible for arousal. • Neurons (see next slide) in the cerebral cortex (responsible for thinking, learning, creativity, memory and emotion, and decision-making) are responsible for awareness. • Diffuse dysfunction of cerebral hemispheres and diffuse or focal dysfunction of the RAS can cause coma. • Structural causes produce dysfunction in ARAS; most metabolic causes result in general dysfunction of cerebral hemispheres.

7. Diagnosis of Coma • Patients in coma lie with their eyes closed and are unable to interact meaningfully with the environment. Patients do not communicate or perform intentional movements. Specific diagnostic criteria for coma is presented on next slide. • Coma is a time-limited condition; by 4 weeks after onset, surviving individuals have either emerged into more responsive states or have begun exhibiting signs of the vegetative state (VS).

8. Neurobehavioral Criteria for the Diagnosis of Coma 1. Eyes do not open spontaneously or to stimulation 2. Patient does not follow commands 3. Patient does not mouth or utter recognizable words 4. Patient does not demonstrate intentional movements 5. Patient cannot sustain visual pursuit movements when eyes are manually held open 6. Criteria 1 through 5 are not secondary to use of paralytic agents SOURCE: American Congress of Rehabilitation Medicine. Recommendations for use of uniform nomenclature pertinent to patients with severe alterations in consciousness. Arch Phys Med Rehab 1995;76:205–209.

9. Diagnosis of Vegetative State • Patients in VS: • have the ability to open eyes and long periods of wakefulness • lack meaningful interaction with the environment • may open their eyes spontaneously or in response to stimuli • cannot communicate, follow commands, or demonstrate intentional movements. • For diagnosis to be considered, a number of conditions must be met (see next slide).

10. Neurobehavioral Criteria for the Diagnosis of the VS • no evidence of awareness of self or environment, no volitional [إرادي] response to visual, auditory, tactile or noxious stimuli and no evidence of language comprehension or expression • presence of cycles of eye closure and eye opening • sufficient preservation of hypothalamic and brain-stem function to ensure maintenance of respiration and circulation • incontinence of bladder and bowel • no visual fixation or tracking • Inconsistent motor activity, without purpose and explainable as a reflex response to external stimuli SOURCE: Royal College of Physicians of London (1996) The permanent vegetative state. Report by a working group convened by the Royal College of Physicians and endorsed by the Conference of Medical Royal Colleges and their faculties of the United Kingdom. Journal of the Royal College of Physicians of London 30: 119–21.

11. Medical Management of a Patient With Coma • The main goal of medical management is to identify and treat the underlying cause of coma. • Initial emergency medical treatment aims to support vital functions and prevent neurologic deterioration. • Patients often need airway protection and ventilatory assistance. • If the cause of coma is not immediately known, experts suggest the administration of , at least, 100 mg of thiamine [vitamin B1], followed by glucose and opoid antagonist [naloxone]. • Unresolved coma after emergency treatment requires supportive measures to maintain physiologic body functions and prevent complications. • Intubation and nutritional support are essential. Anticonvulsant therapy may be indicated to prevent further brain damage due to ischemia.

12. Nursing Management of a Patient With Coma • Nursing diagnoses: • Ineffective airway clearance related to excessive secretions. • Ineffective breathing pattern related to decreased lung expansion. • Imbalanced nutrition: Less than body requirements related to lack of exogenous nutrients. • Risk for aspiration. • Risk for infection • Nurses are responsible for monitoring and assessing changes in neurologic status. • Nurses support body functions by promoting pulmonary hygiene [postural drainage, deep breathing, coughing], maintaining skin integrity, initiating range-of-motion exercises, and ensuring adequate nutritional support. Of particular importance is nurses’ attention to eye care which is presented next.

13. Eye care: • The blink reflex is often diminished or absent in a comatose patient. Blinking is an essential function of the eye that helps spread tears across, protects the eye from, and remove, irritants. Blinking moistens the eye by irrigation using tears and a lubricant the eyes secrete. The eyelid provides suction across the eye from the tear duct to the entire eyeball to keep it from drying out. • Loss of the blink reflex results in drying and ulceration of the cornea which may lead to permanent blindness. • Therefore, nurses play a vital role in protecting the eyes of a comatose patient by normal saline instillation every 2 hours and tapping the eyelids in the shut position.