Sleep - 3: Clinical presentation and diagnosis of the obstructive sleep apnoea hypopnoea
10 AHI was the sum of the number of apnoeas and hypopnoeas
per hour of sleep.
BMI was predictive of the rate of obstructive apnoea and hypopnoea
A few periods of apnoea or hypopnoea
may arise during REM sleep.
Epidemiologic studies suggest a high prevalence of both obstructive and central sleep apnoeas, in the elderly (1-6,8-11), with a significant association between age and apnoea-hypopnoea
index (AHI, number of apnoeas and hypopnoeas
per hour of sleep).
is defined as a reduction in airflow (30-50%) that is followed by an arousal from sleep or a decrease in oxyhaemoglobin saturation (3-4%) (5,6).
The diagnosis of OSA is confirmed when a person has an apnoea-hypopnoea
index (AHI; number of apnoeas and hypopnoeas
per hour of sleep) > 5 events/h associated with symptoms of excessive daytime sleepiness (1).
Whether or not a variation in breathing is great enough to be counted as a hypopnoea
is defined by agreed upon but arbitrary rules which are applied with more or less rigor and can vary somewhat from laboratory to laboratory (4,11).
Patients with upper airway resistance syndrome (UARS), an entity characterized by flow-limited breathing that results in the disruption of sleep, typically have Pcrit levels between snoring and hypopnoea
The treatment goal should be to normalize the apnoea hypopnoea
index (AHI), but normalizing all levels of AHI in all subsets of patients may not result in improved health outcomes.
The reported success rate of these procedures ranges from 75-100 per cent and long-term improvements in apnoea hypopnoea
index (AHI) and quality of life are seen in about 90 per cent of those who have had MMA (49).
While the prevalence of SDB in the general population is 5-12 per cent using an apnoea hypopnoea
cut off of greater than 15, several studies in the advanced CKD patient population have shown a much higher prevalence; ranging from 18 to 80 per cent (6-10).