Biomedical subjects

H A K Browne

Publications and source records attributed to H A K Browne.

2 recordsLinked to original sources

PubMed2003

Sleep apnoea and daytime function in the elderly--what is the impact of arousal frequency?

Arousals from sleep result in hyperventilation and hypocapnia that can lead to sleep apnoea. We have investigated whether sleep apnoea in the elderly is associated with more arousals compared with younger people. Additionally, the impact of arousals on daytime symptoms was noted. Four groups (n = 11) of elderly (> 65 years) and young (< 39 years) apnoeic (EA and YA), and age-matched non-apnoeics (EN and YN) were studied. The arousal index (AI) and apnoea/hypopnoea index were determined from polysomnography. Sleepiness (Epworth Sleepiness Scale) and Quality of life (QoL, SF-36) were assessed. The mean (SD) AI was: EN 23.1 (7.6), EA 46.5 (8.8), YN 13.2 (6.6), YA 38.5 (12.1) events/h. AI was higher in the elderly (P = 0.002) and in apnoeics (P = 0.001); however, the increase in AI associated with sleep apnoea was not age dependent (P = 0.73). The influence of sleep apnoea on sleepiness was similar in both age groups. YA but not EA reported reduced physical functioning (P = 0.04), vitality (P = 0.007) and general health (P = 0.04) compared to non-apnoeics. We conclude that (1) the effect of sleep apnoea on arousal is no greater in the elderly compared to the young (2) despite similar levels of sleepiness, elderly apneoics perceive a reduced loss of QoL compared to younger patients.

Adult↗

PubMed2003

Ageing does not influence the sleep-related decrease in the hypercapnic ventilatory response.

In young people, a sleep-related reduction in the gain of the ventilatory chemoreflex feedback loop occurs; in the elderly, it has been reported that no sleep-related reduction occurs. A relatively high loop gain could contribute to periodic breathing and central sleep apnoea in the elderly. This study tested the hypothesis that ageing is associated with a reduction in the magnitude of the sleep-related decrease in the hypercapnic ventilatory response (HCVR). The HCVR was measured using a steady state method, awake and asleep, in groups (n = 10) of elderly (66-81 yrs) and young (23-35 yrs) nonapnoeics. Upper airway resistance was maintained close to wakefulness levels using continuous positive airway pressure (mean sleep-related increase in resistance: elderly 1.6 +/- 1.2 cmH2O L x s(-1), young 1.2 +/- 0.8 cmH2O x L x s(-1)). The sleep-related decrease in the HCVR was similar in the elderly and young groups (elderly: wake 0.14 +/- 0.06 and sleep 0.06 +/- 0.02 L min(-1) x kPa and young, wake 0.19 +/- 0.07 and sleep 0.10 +/- 0.04 L x min(-1) x kPa). Ageing per se was shown not to change the magnitude of the sleep-related decrease in hypercapnic ventilatory response. The authors speculate that age-related changes in the hypercapnic ventilatory response are unlikely to contribute to the increased prevalence of central sleep apnoea in the elderly.

Aged↗