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Evaluating a Case of SleepApnoea

Dr J.M. Joshi

Professor and Head

Department ofPulmonary Medicine

T.N. Medical CollegeB.Y.L. Nair Hospital

Mumbai

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SAS

Sleep apnoea syndromes (SAS) represent agroup of conditions with abnormal respirationduring sleep

3 forms of sleep apnea: OSA, CompSAS andCSA constitute 84% 15% and 0.4%, of casesrespectively

Obstructive sleep apnea syndrome-OSAS(objective sleeping respiratory disturbance with

daytime sleepiness) Nasal continuous positive airway pressure

(CPAP) is the most effective treatment forpatients with moderate to severe OSAS

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Obstructive Apnoea

ObstructiveApnoeawhen completeclosure of the upper airway

The respiratory efforts continue

airflow

chest

abdomen

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Central Apnoea

Central Apnoea complete cessation of effort tobreathe

Airway still open but no respiratory drive, henceno respiratory muscle activity

airflow

chest

abdomen

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CLINICAL FEATURES

Snoring is the cardinal symptom, cyclical withperiods of loud snoring exceeding 100 decibels orsnoring alternating with quieter intervals of apnoeas

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Diagnosis of OSA

A) EDS

B) 2 of the following Snoring

Witnessed apnoeas Unrefreshing sleep Daytime fatigue Poor concentrationAnd

c) Sleep Study showing AHI > 5

Ref: PSG Task Force, ASDA. Sleep 1997;20:406-22.

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PSG Before and After CPAP

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Severity Grading of OSAS

Mild: 515 events/hour of sleep

Moderate: 1530 events/hour of sleep and

Severe: more than 30 events/hour of sleep

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Conventional DiagnosticTherapeutic Approach

Full polysomnography (PSG) is currently the goldstandard for the diagnosis of OSAS and titration of

effective continuous positive airway pressure (CPAP)

Technicians should titrate CPAP pressures overnightuntil most of the apnoeas and arousals are abolished,

as monitored by PSG

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Alternative AmbulatoryDiagnostic Therapeutic Approach

Urgent need to evaluate approaches tomanagement that did not unduly rely on sleeplaboratorybased PSG studies led to

Diagnostic-therapeutic approach using homebased limited PSG (cardio-respiratoryvariables only) or oximetry with ambulatory

CPAP titration

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Clinical Probability of OSAS

Ambulatory diagnostic-therapeutic approachrequires accurate identification of probablecases of OSAS

Sleepy snorer by Epworth Sleepiness Score

Sleep Apnea Clinical Score (SACS)based onsnoring, witnessed episodes of apnea, neck

circumference, and systemic hypertension

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Epworth Sleepiness Score

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Summary

Magnitude of OSA and paucity of sleep labs needssimplified approaches for physicians

Enough evidence now exists that simple

ambulatory diagnostictherapeutic strategies haveequivalent clinical outcome in cases with highpretest probability

Patients who have a low probability, have co-

morbidities or have difficulties during ambulatorymanagement should be referred to a sleep centrefor detailed evaluation/in-laboratory attended fullPSG and further management