Biomedical subjects

Justin C T Pepperell

Publications and source records attributed to Justin C T Pepperell.

4 recordsLinked to original sources

PubMed2004

Stroke and blood pressure variability.

Sleep apnoea is associated with increased cardiovascular risk. Sleep apnoea is common after stroke and associated with increased blood pressure variability as described by Turkington and co-workers in this issue of Clinical Science. Both sleep apnoea and blood pressure variability confer a poor prognosis after stroke and are potentially treatable. Many studies of CPAP (continuous positive airway pressure) demonstrate decreases in cardiovascular risk markers in other patient groups. Although difficult to apply in these patients in the short term, CPAP has some potential benefits in medium-term rehabilitation and secondary prevention following stroke, which warrants further study.

Blood Pressure↗

PubMed2003

A randomized controlled trial of adaptive ventilation for Cheyne-Stokes breathing in heart failure.

Heart failure is associated with Cheyne-Stokes breathing, which fragments patients' sleep. Correction of respiratory disturbance may reduce sleep fragmentation and excessive daytime sleepiness. This randomized prospective parallel trial assesses whether nocturnal-assist servoventilation improves daytime sleepiness compared with the control. A total of 30 subjects (29 male) with Cheyne-Stokes breathing (mean apnea-hypopnea index 19.8 [SD 2.6] and stable symptomatic chronic heart failure (New York Heart Association Class II-IV) were treated with 1 month's therapeutic (n = 15) or subtherapeutic adaptive servoventilation. Daytime sleepiness (Osler test) was measured before and after the trial with change in measured sleepiness the primary endpoint. Secondary endpoints included brain natriuretic peptide levels and catecholamine excretion. Active treatment reduced excessive daytime sleepiness; the mean Osler change was +7.9 minutes (SEM 2.9), when compared with the control, the change was -1.0 minutes (SEM, 1.7), and the difference was 8.9 minutes (95% confidence interval, 1.9-15.9 minutes; p = 0.014, unpaired t test). Significant falls occurred in plasma brain natriuretic peptide and urinary metadrenaline excretion. We conclude that adaptive servoventilation produces an improvement in excessive daytime sleepiness in patients with Cheyne-Stokes breathing and chronic heart failure. This study suggests improvements in neurohormonal activation with this treatment.

Aged↗

PubMed2002

Ambulatory blood pressure after therapeutic and subtherapeutic nasal continuous positive airway pressure for obstructive sleep apnoea: a randomised parallel trial.

BACKGROUND: Obstructive sleep apnoea is associated with raised blood pressure. If blood pressure can be reduced by nasal continuous positive airway pressure (nCPAP), such treatment could reduce risk of cardiovascular disease in patients with obstructive sleep apnoea. Our aim was to see whether nCPAP for sleep apnoea reduces blood pressure compared with the most robust control intervention subtherapeutic nCPAP. METHODS: We did a randomised parallel trial to compare change in blood pressure in 118 men with obstructive sleep apnoea (Epworth score > 9, and a > 4% oxygen desaturation index of > 10 per h) who were assigned to either therapeutic (n=59) or subtherapeutic (59) nCPAP (about 1 cm H(2)O pressure) for 1 month. The primary outcome was the change in 24-h mean blood pressure. Secondary outcomes were changes in systolic, diastolic, sleep, and wake blood pressure, and relations between blood pressure changes, baseline blood pressure, and severity of sleep apnoea. FINDINGS: Therapeutic nCPAP reduced mean arterial ambulatory blood pressure by 2.5 mm Hg (SE 0.8), whereas subtherapeutic nCPAP increased blood pressure by 0.8 mm Hg (0.7) (difference -3.3 [95% CI -5.3 to -1.3]; p=0.0013, unpaired t test). This benefit was seen in both systolic and diastolic blood pressure, and during both sleep and wake. The benefit was larger in patients with more severe sleep apnoea than those who had less severe apnoea, but was independent of the baseline blood pressure. The benefit was especially large in patients taking drug treatment for blood pressure. INTERPRETATION: In patients with most severe sleep apnoea, nCPAP reduces blood pressure, providing significant vascular risk benefits, and substantially improving excessive daytime sleepiness and quality of life.

Adult↗

PubMed2002

Systemic hypertension and obstructive sleep apnoea.

This article is a review of the current evidence that links systemic hypertension with obstructive sleep apnoea. Whilst a causal association has been suspected for some time, the day to day variability of both blood pressure and sleep apnoea severity, and clustering of confounding cardiovascular risk factors in sleep apnoea patients has made this association difficult to prove. There is unassailable evidence that obstructive apnoeas raise blood pressure acutely in both animal models and humans, through a combination of autonomic and state dependent arousal with some mechanical influences, and these rises can be controlled by nasal continuous positive airway pressure. Thus, although repetitive apnoeas alter the blood pressure variability and raise sleeping blood pressure in patients with OSA and sophisticated animal models have demonstrated increases in daytime blood pressure after the onset of OSA in the short term, such effects on diurnal BP have yet to be proven in humans. Recent rigorously designed large epidemiological studies have proven an independent association between OSA and systemic hypertension in both general and sleep clinic populations, with closely matched case control series also reporting raised blood pressure in OSA patients. A direct temporal causal association between the onset of obstructive sleep apnoea and raised blood pressure is expected to be confirmed by longitudinal data from the continuing epidemiological population studies. Finally, several studies on the beneficial effects of nasal continuous positive airway pressure in reducing blood pressure in OSA patients have preliminary results in abstract form, with one published in full.

Animals↗