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Results for “UNCONSCIOUSNESS”

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At least 955 records · Page 53Linked to original sources
PubMed1991

[Experience with flash-evoked visual potentials in unconscious patients in the neurologic intensive care station].

Evoked potential monitoring has become a widely used procedure in the evaluation of stuporous patients on neurological intensive care units. Currently BAEP and SEP are preferentially employed. VEP monitoring is a relatively uncommon procedure, because late evoked potentials tend to be relatively unstable, varying in amplitude to a moderate extend from changes of temperature, drugs, attention and the level of consciousness. A valuable approach of VEP monitoring on intensive care units are structures of the visual system at risk in vascular disease of the vertebrobasilar system or during evaluated intracranial pressure (EIP). This study uses the data of 20 stuporous patients presenting with either intracranial mass lesions or vascular diseases of the vertebrobasilar system and 20 control persons. Light emitting diode (LED)-VEP are compared with checkerboard stimulation in control persons using the technique of cross-correlation. The comparison of the control group with patients using LED-VEP allows definition of limits for normal variation as a base for identification of significant changes. Despite methodical restrictions of LED-VEP, our results are in favour of serial studies in patients with EIP. There are no corresponding findings in LED-VEP and vascular lesions of the retrochiasmatic visual system.

Adult↗
PubMedDate not supplied

[The dynamics of the evoked bioelectrical activity of the brain in unconscious states].

In 93 patients with mental disorders evoked bioelectrical activity of brain was studied in states of changed consciousness. Methods of evoked potentials and conditioned negative wave were applied. The obtained data allow to consider that in parameters and dynamics of bioelectrical activity changes of consciousness sphere are reflected.

Adult↗
PubMedDate not supplied

Unconsciousness in flight and its prevention.

The physiological mechanism underlying two of the most potent causes of loss of consciousness in flight, viz. hypoxic hypoxia and exposure to rapid onset of high +GZ accelerations have been explored in this paper, using principally experimental work conducted at the Royal Air Force Institute of Aviation Medicine. The influence of the composition of the gas breathed before and after sudden decompression of the pressure cabin of an aircraft at high altitude has been described together with the physiological basis of the present standards for preventing disturbances of performance due to hypoxia following rapid decompression. The value and limitations of pressure breathing with oxygen at high pressures in preventing hypoxia on exposure to altitudes above 40,000 feet have been discussed together with the series of partial pressure suits used in the Royal Air Force. The mechanisms and occurrence of G-induced loss of consciousness in pilots of combat aircraft have been reviewed. The increasing likelihood of loss of consciousness due to G in new very agile combat aircraft is considered together with the limitations of the standard methods of enhancing G tolerance. The adoption and development of pressure breathing together with chest counterpressure and extended-cover G trousers which provide excellent protection against high levels of acceleration is described.

Acceleration↗
PubMed1990

Effect of rate of induction of carbon dioxide anaesthesia on the time of onset of unconsciousness and convulsions.

The effect of different rates of induction of carbon dioxide anaesthesia on the time to loss of consciousness was investigated in broilers and hens. In experiment 1, 24 and 17 broilers, respectively, were exposed to 45 per cent carbon dioxide within 8 or 18 seconds (accession time). In experiment 2, 18 to 20 broilers and hens were exposed to either 35, 45, 55 or 65 per cent carbon dioxide within 8 seconds. The results indicated that, in general, the rate of accession is more critical than the final concentration of carbon dioxide; however, in 35 per cent carbon dioxide an exposure time of longer than 5 minutes is required to kill the birds. The time to sustained eye closure, time to onset of clonic and tonic convulsions and the duration of convulsive episodes were shorter in broilers than in hens. It is suggested that under commercial situations a final concentration of 55 per cent carbon dioxide would be suitable for killing broilers and hens.

Abattoirs↗