The pattern that Likhita S described, and that brings a consistent stream of patients to my clinic at Fortis Hospital, Anandapur, is one of the most recognisable in sleep medicine: years of snoring, a bed partner who notices breathing that stops and then resumes with a gasp, and a patient who wakes from eight hours of sleep more exhausted than when they went to bed, whose concentration at work has been progressively declining, and who has attributed all of this to stress, age, or the demands of Kolkata's working life. The diagnosis is obstructive sleep apnoea. The treatment is CPAP. The outcome, when the diagnosis is made and the therapy is properly initiated and followed up, is often described by patients as one of the most significant improvements in quality of life they have experienced from any medical intervention. Likhita S's description of the difference in daytime energy and concentration after CPAP initiation is the outcome that my sleep medicine expertise allows me to produce for patients across Kolkata who have been living with undiagnosed OSA for years. Sleep apnoea is one of the most prevalent under-diagnosed conditions in Kolkata's urban professional population, and the specialist pulmonologist who practices sleep medicine is the clinician best positioned to diagnose it accurately and manage it comprehensively.
The Home Sleep Study: What It Measures and How the AHI Determines Treatment
The home sleep study, also called an ambulatory sleep study or home sleep apnoea test, is the investigation that has transformed sleep apnoea diagnosis from a procedure requiring overnight hospital admission to a practical and accessible investigation that most patients can complete in their own bedroom. The patient takes home a portable monitoring device that is applied before sleep and worn through the night. The device records oxygen saturation continuously, measures airflow through a nasal sensor, monitors respiratory effort through chest and abdominal bands, and records body position. From these recordings, the apnoea-hypopnoea index, or AHI, is calculated: the number of apnoeas, which are complete breathing pauses lasting ten seconds or more, and hypopnoeas, which are partial airflow reductions associated with oxygen desaturation or arousal, per hour of sleep. This single number drives the management decision. An AHI below five per hour is normal. AHI five to fifteen is mild OSA. AHI fifteen to thirty is moderate. AHI above thirty is severe. A patient with severe OSA is having thirty or more complete or partial breathing pauses every hour through the night, each one producing a dip in oxygen saturation, a surge in sympathetic nervous system activity, and a fragmentation of sleep architecture that prevents the deep restorative sleep stages from being reached and sustained. In Kolkata's urban professional population, where the combination of obesity rates rising with dietary transition, sedentary working patterns, and high-stress occupational demands creates a population profile with high OSA prevalence, the home sleep study is the practical investigation that confirms or excludes the diagnosis without requiring hospital admission or disrupting work schedules.
Cardiovascular Consequences, CPAP Initiation, and When to Choose BIPAP
Untreated obstructive sleep apnoea is not simply a quality of life problem: it is a cardiovascular risk factor with a specific and well-characterised mechanism of harm. Each apnoeic episode produces hypoxaemia, a surge in sympathetic nervous system activity, and a spike in blood pressure at the moment of arousal that reopens the airway. In a patient with thirty or more episodes per hour, this cardiovascular stress is repeated hundreds of times each night. The cumulative effect produces sustained hypertension that is characteristically resistant to antihypertensive medication because the driving mechanism is operating during the hours of sleep when the medication cannot adequately suppress it. OSA is independently associated with atrial fibrillation, a two-fold increased risk of stroke, a higher risk of cardiac events, and a strong bidirectional relationship with type 2 diabetes through the insulin resistance that chronic intermittent hypoxaemia and sympathetic activation promote. In Kolkata's urban population, where hypertension, type 2 diabetes, and cardiovascular disease are already prevalent and rising, the identification and treatment of OSA in patients with these comorbidities may meaningfully reduce the cardiovascular burden that currently drives hospital admissions. CPAP therapy, which delivers a continuous stream of pressurised air through a mask worn during sleep to act as a pneumatic splint keeping the upper airway open, is the most effective treatment for OSA across all severity grades. Pressure is determined during an in-clinic titration or using an auto-titrating device that adjusts pressure breath by breath. The compliance challenge, getting patients to wear the mask consistently throughout the night, is addressed through careful mask fitting, close follow-up in the first weeks of therapy, and troubleshooting of pressure, leak, and comfort issues as they arise. BIPAP, bilevel positive airway pressure, which delivers a higher pressure during inhalation and a lower pressure during exhalation, is chosen over CPAP for patients who cannot tolerate the exhalation pressure of CPAP therapy, for patients with concurrent hypercapnic respiratory failure, and for patients with the overlap syndrome of OSA and COPD where the lower exhalation pressure is both more comfortable and more physiologically appropriate
To book a pulmonology consultation with Dr. Subhajit Sen at Fortis Hospital, 730, Eastern Metropolitan Bypass, Anandapur, Kolkata, West Bengal 700107 (Monday to Saturday, 2:00 PM to 5:00 PM), call +91 9007734015.
Written by Dr. Subhajit Sen, MBBS (Medical College, Calcutta), MD (IPGME&R, Calcutta), DNB (Respiratory Medicine, Apollo Hospital Calcutta, National Board of Examinations), EDARM (European Diploma in Adult Respiratory Medicine), DRNB (Critical Care), Consultant Pulmonologist and Critical Care Specialist, Fortis Hospital, 730, Eastern Metropolitan Bypass, Anandapur, Kolkata, West Bengal 700107 (Monday to Saturday, 2:00 PM to 5:00 PM). Phone: +91 9007734015. Also consulting at Apollo Clinic Bansdroni, Golf View Hospital Tollygunge, and Medisus Lab and Clinic, Kolkata.
Related reading
Meet Dr. Subhajit Sen: Respiratory Medicine, Critical Care, and Allergy in West Bengal
Critical Care Medicine: Why the Specialist Pulmonologist Changes Outcomes in Respiratory Failure
Add a Comment