title: Evaluation of an alternative definition for the apnea-hypopnea index.
abstract: The apnea-hypopnea index (AHI) plays a major role in determining whether a patient suffers from SAHS, as well as in evaluating the severity of his/her condition. To obtain this index the number of apneas and hypopneas that the patient has experienced during his/her sleep is calculated, and the result is divided by the number of hours of sleep. The standard definitions of apnea and hypopnea require that these events have a minimum temporal span of 10 seconds. Our experience has taught us that some respiratory airflow limitations lasting less than 10 seconds can produce a noticeable effect on the patient's blood oxyhemoglobin saturation (SpO2). In this paper we propose alternative definitions for apnea and hypopnea events that include respiratory airflow limitations with a temporal span between 5 and 10 seconds when they are associated with a drop in SpO2 of at least 3%. Then we compare the AHI calculated using the standard definition and our definition over a database of 40 polysomnograms. For 2 of the 40 patients, the standard AHI clearly underestimates the severity of the patient's condition, while ours does not.
authors.affiliation: Department of Information and Communications Systems Engineering, University San Pablo CEU, 28668 Madrid, Spain. abraham.otero@usc.es
authors.forename: Abraham
authors.initials: A
authors.lastname: Otero
authors.forename: Paulo
authors.initials: P
authors.lastname: Felix
authors.forename: Jesus
authors.initials: J
authors.lastname: Presedo
authors.forename: Carlos
authors.initials: C
authors.lastname: Zamarron
mesh_terms: D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006801:Humans; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000145:classification* / Q000175:diagnosis*; D009626:Terminology as Topic