Ventilation and chemoreflexes during enflurane sedation and anaesthesia in man

Knill, R. L.; Manninen, Pirjo; Clement, J. L.

doi:10.1007/bf03006447

Cited by 78 publications

(9 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…One of the suggested reasons for the difference in results was that Knill et al [1,2] had used Read's rebreathing method to induce hypercapnia (the end-tidal PCO 2 rises progressively over several minutes as air, or oxygenenriched air, is rebreathed from a large bag), whereas Dahan et al [3] used step hypercapnia (end-tidal PCO 2 rises rapidly to the desired level within seconds). Subsequent studies have explored these observations [4][5][6][7][8][9][10][11][12][13][14]. The original studies of Knill et al [1,2,5,10] found that some agents (N 2 O, enflurane and isoflurane) did indeed depress the ventilation-CO 2 response, but other agents (ether and methoxyflurane), like halothane, had no effect.…”

mentioning

confidence: 99%

Effect of low dose inhaled anaesthetic agents on the ventilatory response to carbon dioxide in humans: a quantitative review

Pandit

2005

Anaesthesia

View full text Add to dashboard Cite

SummaryThis paper reviews published studies (identified by a Medline-assisted search) on the effect of £ 0.2 minimum alveolar concentration inhaled anaesthetic agents on the hypercapnic ventilatory response in healthy subjects. Each article was examined for the anaesthetic agent used, whether CO 2 was administered using a rebreathing or a steady state (step hypercapnia) technique, and subject arousal (by audiovisual stimulation or by pain). Analysis of variance was used to assess the influence of each of these factors on the standardised hypercapnic response (the hypercapnic ventilatory response in l.min )1 .kPa )1 in the presence of anaesthetic, expressed as a fraction of the response without anaesthetic). There were 21 separate studies embedded within 14 published articles. When considered together, the effect of anaesthetics on the hypercapnic ventilatory response was not significant (p = 0.089). Furthermore, when each agent was considered separately, no agent alone had a significant effect on the hypercapnic response. Neither subject arousal (p = 0.396) nor the method used to induce hypercapnia (p = 0.625) had any significant influence on the response. This suggests that the hypercapnic response is more resistant to the effects of anaesthetics than the hypoxic ventilatory response. These results indicate areas for future work. It would seem important to identify the cellular mechanisms which might underlie the difference in hypercapnic and hypoxic responses, and possible ways in which subject arousal might interact in the brain with the chemoreflexes.

show abstract

mentioning

confidence: 99%

Effect of low dose inhaled anaesthetic agents on the ventilatory response to carbon dioxide in humans: a quantitative review

Pandit

2005

Anaesthesia

View full text Add to dashboard Cite

show abstract

“…The observations of Knill et al in the 1970s (since confirmed by many other studies) established that in humans, volatile anaesthetics significantly depress the AHVR [16][17][18]. At low dose (< 0.2 minimum alveolar concentration(MAC)) the degree of depression is …”

Section: Volatile Anaesthetics and Ventilatory Controlmentioning

confidence: 89%

Hypoxia: developments in basic science, physiology and clinical studies

2011

View full text Add to dashboard Cite

SummaryAirway management is primarily designed to avoid hypoxia, yet hypoxia remains the main ultimate cause of anaesthetic‐related death and morbidity. Understanding some of the physiology of hypoxia is therefore essential as part of a ‘holistic’ approach to airway management. Furthermore, it is strategically important that national specialist societies dedicated to airway management do not only focus upon the technical aspects of airway management, but also embrace some of the relevant scientific questions. There has been a great deal of research into causation of hypoxia and the body’s natural protective mechanisms and responses to it. This enables us to think of ways in which we might manipulate the cellular and molecular responses to confer greater protection against hypoxia‐induced tissue injury. This article reviews some of those aspects.

show abstract

“…It has been reported that tobacco smoke and ammonium vapour increase mucociliary activity and this increase can be partially prevented with atropine and substance P. [31,32] Knill et al showed that halothane and enflurane reduced the peripheral chemoreceptor response to hypoxia and doxapram. [33,34] Coleridge stated that anesthetic agents change the high pulmonary tension and the activity of high-threshold receptors. [35] It has been stated that vagal or sympathetic nerve impulses increase the ciliary beat frequency.…”

Section: Discussionmentioning

confidence: 99%