Post-hyperventilation apnoea in patients with brain damage

Jennett, Sheila; Ashbridge, Karen; North, J. B.

doi:10.1136/jnnp.37.3.288

Cited by 16 publications

(9 citation statements)

References 13 publications

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“…Our results support the conclusion that beyond about 1-2 min after the end of VHV, breathing pattern or timing during VHV have no further effect on presence or absence of pauses, and they are in accord with studies showing that the occurrence of apnoea was not related to the level of Pco, reached during HV (Jennett et al 1974;Mangin et al 1982).…”

Section: Discussionsupporting

confidence: 81%

“…Nevertheless, it is a possibility that we may have seen a different spectrum of, and possibly more, apnoeic pauses had we used a less invasive technique. However, others (Plum et al 1962;Jennett et al 1974) found no difference in their results when they substituted impedance pneumography for the mouthpiece and facemask. In our study, there was an inbuilt control in that the responses to the four protocols were compared under identical experimental conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Haldane described apnoeas of 2 min duration (Douglas & Haldane, 1909), found apnoeas ranging from loss of a single breath to 120 s, Moser et al (1965) reported apnoea of up to 10 s, whilst Mangin et al (1982) found a mean duration of 12'6 s with a range of 7-43 s. In the latter study, patients with clinical or EEG evidence of cerebral pathology were included and these may have longer periods of apnoea (Plum et al 1962;Jennett et al 1974). Venous C02 unloading by haemodialysis (De Backer et al 1987) induced irregular breathing and apnoeas of up to 20 s in length associated with a reduction of Pa Co2 to 34 mmHg.…”

Section: Discussionmentioning

confidence: 99%

“…Moser et al (1965) showed more apnoea in hyperoxia, but normal breathing following both active and passive HV has also been described (Ashbridge, Jennett & North, 1972;Jennett, Ashbridge & North, 1974;Skatrud & Dempsey, 1983;Datta et al 1991), as has hyperpnoea, at least in the minute or so following the end of HV (Mills, 1946;Fink, 1961;Tawadrous & Eldridge, 1974;Swanson, Ward & Bellville, 1976;Folgering & Durlinger, 1983;Cummin, Sidhu, Telford & Saunders, 1992). Most of these studies were performed in normoxia.…”

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confidence: 99%

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Post‐hyperventilation apnoea in conscious humans.

Meah

Gardner

1994

The Journal of Physiology

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1. In nine normal subjects, analysis was performed of the number, length and location of apnoeic pauses during 20 min of recovery following voluntary overbreathing (VHV). Based on a definition of apnoea as expiratory time greater than 6 s, apnoeas occurred between mean times of 0-8 and 5-6 min after the end of VHV, the end of this period being associated with a mean PET,cO, value of 36-4 mmHg, which was below the initial mean resting value of 39-8 mmHg. 3. Within this apnoeic period, 80 % of experiments produced apnoeas of less than 10 s duration, 61 % of between 10 and 20 s duration and 42 % of between 20 and 30 s duration. Only one out of nine subjects consistently failed to show apnoeas.4. The range of lengths of individual apnoeas and the number per minute were independent of the length and level of VHV and were not significantly different between the four protocols. 5. The number and length of apnoeas did not change in repeated runs in each subject. We were not able to confirm previous reports that apnoeas occurred more frequently in subjects familiar with the experiment. 6. These results reconciled previous studies showing either apnoea or hyperpnoea following voluntary overbreathing in conscious humans. They showed an initial period of heightened breathing lasting about a minute with few apnoeas, consistent with 'afterdischarge'. Beyond that, apnoeas occurred as an 'all-or-nothing' phenomenon as long as PET,C02 was on average less than 3-4 mmHg below resting PET,co0, The occurrence and length of apnoeas was consistent in individual subjects with no evidence of a learning effect.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Post‐hyperventilation apnoea in conscious humans.

Meah

Gardner

1994

The Journal of Physiology

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“…30-31. Post-hyperventilation apnoea (PHVA) (Plum et al, 1962;Jennett et al, 1974) The subject was instructed to take five breaths as rapidly and as deeply as possible. The time between the fifth and sixth breaths was determined without informing the subject.…”

Section: Physical Signs and Mental Status Itemsmentioning

confidence: 99%