The blink reflex in coma and after recovery from coma

Serrats, A. F.; Parker, S. A.; Merino-Cañas, A.

doi:10.1007/bf01405865

Cited by 19 publications

(8 citation statements)

References 20 publications

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“…The correlation of coma grade and BR changes demonstrated that prognosis is better when R2 is present [14]. A close correlation has been reported between survival and a positive R1 during the first investigation [27], followup recordings having a high predictive value [27,104,113].…”

Section: Blink Reflexsupporting

confidence: 41%

Evoked potentials and brain stem reflexes

Klug¹,

Csécsei

1985

Neurosurg. Rev.

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The recording of evoked potentials (EPs) has become one of the most useful functional diagnostic techniques in the neurosciences during recent years. In combination with the neurophysiological investigation of brain stem reflexes (BSRs) EPs provide good information concerning circumscribed and diffuse brain and brain stem lesions. In this article the role of EPs and BSRs will be pointed out with special regard to their use in neurosurgery concerning awake and comatose patients as well. Pathological findings caused by extracerebral factors or due to neurological (systemic) and otological diseases will be discussed from the aspect of differential diagnosis only. Evoked potentials described in this paper are short latency potentials which are related to more or less defined generators in the peripheral and central nervous system. EPs of long latency seem to play a role in cognitive, affective and integrative functions of the central nervous system and they will not be dealt with in this article. In recent years an increasing number of review articles and monographs dealing with several aspects of evoked potentials has appeared [16, 17, 18, 25, 69, 80, 84, 122, 123, 124, 127, 130].

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Section: Blink Reflexsupporting

confidence: 41%

Evoked potentials and brain stem reflexes

Klug¹,

Csécsei

1985

Neurosurg. Rev.

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“…The effects of altered consciousness on the blink reflex have been studied in and coThe effects of ether13 and barbituma*15, [47][48][49] rate13'16 anesthesia have been studied in animals. In a recent study of intraoperative recording of blink reflexes in patients with hemifacial spasm under isoflurane and nitrous oxide anesthesia, it was reported that "the blink reflex cannot normally be elicited during surgical anesthesia using inhalation anesthetic^.…”

Section: Head 81 Neck 11937-1491989supporting

confidence: 38%

Effects of general anesthesia on the human blink reflex

Marelli¹,

Hıllel

1989

Head & Neck

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The blink reflex was studied in 10 patients undergoing elective procedures under general anesthesia. Anesthetic agents were isoflurane, halothane, nitrous oxide, methohexital, and thiopental in various combinations. At induction, blink reflexes were diminished by low-dose thiopental (1-1.5 mg/kg) and abolished by high-dose thiopental (4-8 mg/kg) and methohexital (1.5 mg/kg). Blink reflexes were absent during halogenated volitile inhalational anesthesia and did not return until patients were in the recovery room, well after end-tidal anesthetic levels were zero by mass spectroscopy. Recovery of consciousness and the ability to blink on command often preceded return of any blink reflex activity, indicating that the blink reflex is not useful as a postoperative test of facial nerve function in the operating room after anesthesia. In six patients, blink reflexes were still diminished 2-3 hours after cessation of anesthesia, at a time when patients were fully oriented and corneal and eyelid reflexes were clinically normal. This finding suggests that the blink reflex might be a sensitive test of subtle CNS dysfunction after inhalational anesthesia and potentially could serve as a useful objective indicator of recovery from anesthesia for outpatient surgery.

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“…In the human medical world, absence of the corneal reflex is considered a worrying sign of brainstem damage (Cruccu et al, 1997). When the corneal reflex cannot be evoked, there is a large probability that the disruption is associated with a wider dysfunction, comprising part of the reticular formation, and thus with a state of unconsciousness (Serrats et al, 1976;Cruccu et al, 1997;Laureys, 2005;Terlouw et al, 2016b). In the study described in Chapter 5, none of the pigs subjected to 80% or 95% CO 2 had a corneal reflex following stunning.…”

Section: Eye Reflexessupporting

confidence: 42%

Assessing unconsciousness in livestock at slaughter

Verhoeven¹

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Verhoeven, M.T.W. (2016). Assessing unconsciousness in livestock at slaughter. PhD thesis, Wageningen University, The Netherlands Assessing unconsciousness in livestock at different stages of the slaughter process is a legal requirement according to EU legislation. The assessment can be based on absence of readily observable indicators (behavioural indicators, physical signs and reflexes) or, under experimental conditions, by recording and subsequent assessment of brain activity as presented in an electroencephalogram (EEG). There is no consensus, however, to what extent different behavioural indicators, physical signs and reflexes accurately reflect unconsciousness. The aim of this thesis was to study the relationships between these readily observable indicators and EEG activity to provide information on 1. the exact point in time at which animals lose consciousness when subjected to different stunning and slaughter methods and 2. the validity of behavioural indicators, physical signs and reflexes used to assess unconsciousness at slaughter under commercial conditions. The results showed a large variation in time to loss of consciousness, based on EEG activity, both between stunning and slaughter procedures and amongst animals. Captive bolt stunned calves lost consciousness instantly following the stun. Loss of consciousness in pigs during CO 2 stunning varied from 21 to 61 s after start of the exposure. An increased CO 2 concentration decreased the time to loss of consciousness. Times to loss of consciousness in sheep slaughtered without stunning varied from 6 to 24 s. In cattle slaughtered without stunning, times to loss of consciousness varied from 14 s up to over two minutes. Following captive bolt stunning in calves, absence of reflexes indicated unconsciousness. When consciousness was lost gradually (e.g. CO 2 stunning and nonstunned slaughter) none of the readily observable indicators could identify the exact point in time at which animals lost consciousness. Absence of rhythmic breathing, corneal reflex-and eyelid reflex were valid indicators of unconsciousness following CO 2 stunning and non-stunned slaughter, but these indicators were quite conservative as they were initially absent long after EEG activity indicated unconsciousness. When presence of these indicators would require (re)stunning, many animals will have to be (re)stunned. The results also showed that under full commercial conditions, stunning effectiveness must be closely monitored by slaughter plant employees, since risks for stun failures are higher under commercial conditions compared to experimental conditions. CONTENTS

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The blink reflex in coma and after recovery from coma

Cited by 19 publications

References 20 publications

Evoked potentials and brain stem reflexes

Evoked potentials and brain stem reflexes

Effects of general anesthesia on the human blink reflex

Assessing unconsciousness in livestock at slaughter

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