A CPAP titration study is a specialized overnight sleep test used after a diagnosis of obstructive sleep apnea to determine the precise air pressure setting needed for effective treatment. This procedure combines the comprehensive monitoring of a standard polysomnogram with the application of a Continuous Positive Airway Pressure (CPAP) machine. The purpose of the study is to find the minimum pressure, measured in centimeters of water (cmH2O), that successfully eliminates all breathing interruptions while a person sleeps.
Pre-Study Preparation
Preparation for the study begins well before arrival at the sleep center, focusing on maintaining a normal routine to encourage natural sleep patterns. Patients are instructed to avoid napping and adhere to their usual bedtime schedule. Avoiding caffeine and alcohol after lunchtime is crucial, as these substances can disrupt sleep and breathing, potentially skewing the test results.
Patients should communicate with their sleep physician about all current medications, especially stimulants or sedatives, to determine if intake adjustments are necessary. Hair sprays, oils, or heavy gels should be avoided as these products can interfere with the adherence of the scalp sensors. Bringing comfortable pajamas and personal items that aid sleep helps create a familiar environment.
The Setup and Monitoring Process
Upon arriving at the sleep lab, the patient is shown a private room designed to resemble a hotel room. Before sleep begins, the technologist applies numerous sensors to the body to capture a physiological portrait of the night. These electrodes monitor:
- Brain waves (EEG)
- Eye movements (EOG)
- Muscle tone (EMG)
- Heart activity (EKG)
Additional sensors measure respiratory function, including airflow sensors near the nose and mouth, bands around the chest and abdomen to track breathing effort, and a pulse oximeter to monitor blood oxygen saturation. The technologist fits the CPAP mask (nasal pillow, nasal mask, or full-face mask), ensuring a comfortable and leak-free seal. Connections are confirmed secure by having the patient perform small movements prior to the lights being turned off.
The Titration Phase During Sleep
Once the patient is asleep, the titration process begins, guided by the technologist monitoring the data remotely from an adjacent control room. The CPAP machine is initially set to a low pressure, around 4 cmH2O. The technologist watches the live data stream for obstructive respiratory events, such as apneas, hypopneas, or respiratory effort-related arousals (RERAs).
When an obstructive event is detected, the technologist increases the air pressure in small increments of 1 cmH2O, waiting at least five minutes between adjustments to assess the effect. This systematic increase continues until all obstructive events are eliminated, oxygen saturation remains above 90 percent, and the breathing pattern becomes regular. The goal is to identify the lowest effective pressure that reduces the Apnea-Hypopnea Index (AHI) to below five events per hour.
If the required pressure becomes uncomfortably high (exceeding 15 cmH2O) or if obstructive events persist, the technologist may switch the patient to a BiPAP machine. BiPAP delivers two different pressures—a higher one for inhalation (IPAP) and a lower one for exhalation (EPAP)—which can improve comfort and efficacy. This manual adjustment ensures the final prescribed setting is precisely tailored to the individual’s needs across various sleep stages and positions.
After the Study: Results and Prescription
The study concludes the following morning when the technologist wakes the patient and removes all monitoring sensors and the CPAP mask. Patients are free to leave and return to their normal daily activities immediately. The raw data collected overnight is then scored and analyzed by the sleep physician.
The final report, containing the optimal pressure setting, is sent to the prescribing physician. Results are not available immediately, requiring a follow-up appointment, usually within one to two weeks, to discuss the findings. This finalized effective pressure setting serves as the basis for the physician’s prescription for the home CPAP machine and necessary supplies.