What is a Sleep Test?
A sleep study (Polysomnogram), measures the number of apnea episodes per hour and is called the AHI(Apnea- Hypopnea-Index). Hypopnea is a cessation of breathing for ten or more seconds. Your AHI is graded as mild (5-15 episodes per hour), moderate (15-25 per hour), or severe (30 or more episodes per hour).
Major types of sleep studies include:
Diagnostic PSG: This provides the most information. Central and Obstructive apneas are recorded and if the report indicates apnea and the pulmonary physician wants the patient to attempt CPAP therapy the patient must return to the lab for a CPAP titration study.
CPAP Titration: The patient returns to lab to be fitted with the CPAP machine and mask. Once sleep onset takes place the patient with mask already on has the oxygen pressure gradually increased by the sleep technician until the apnea events are minimal or non-existent. This is the setting that the patient uses at home. It is called titrating the mask.
Split-Night Titration: Many patients and physicians prefer this type of sleep study. The first half of the night the patient is tested for sleep apnea. The patient is then woken up, a CPAP mask is fitted and the study continues for the rest of the night.
The pulmonary physician will determine the best sleep test based on the patient’s individual medical history and current circumstance. These sleep tests may be conducted at home (with an ambulatory sleep test device that we provide you) or at a qualified sleep center for comprehensive evaluation. The results of this initial sleep test will determine if Dr. Williams will refer you to a sleep specialist for proper diagnosis.