Response of Automatic Continuous Positive Airway Pressure Devices to Different Sleep Breathing Patterns

Abstract

Evaluating the usefulness of automatic continuous positive airway pressure (CPAP) in treating the sleep apnea-hypopnea syndrome (SAHS) is not easy because the algorithms for automatic CPAP implemented in the devices available are not well known and are probably dependent on the device. In addition, at present it is not possible to test the behavior of automatic CPAP devices in response to well-defined breathing patterns. Our aim was to implement a bench test to characterize the responses of automatic CPAP devices by subjecting them to breathing patterns of patients with SAHS. To this end, a variety of typical breathing patterns (normal, apneas, hypopneas, flow limitation, snoring) previously recorded in patients with SAHS during sleep were reproduced by a breathing waveform generator. Five commercially available automatic CPAP devices were tested. The responses of the devices to apneas, hypopneas, flow limitation, and snoring were considerably different. In some devices, the response was modified by air leaks similar to the ones found in patients. Consequently, the effectiveness of automatic CPAP assessed in clinical tests performed by using particular devices has no general validity. Testing automatic CPAP devices in a bench study is a useful first step in evaluating the performance of this new type of device in adjusting nasal pressure for each patient.

Método simplificado para la titulación de la presión del CPAP en pacientes con diagnóstico de Síndrome de Apneas Hipopneas del Sueño (SAHS). Serie de casos empleando el equipo autoajustable Autoset T.

“…En función de lo documentado en la literatura (15)(16)(17)(18)(19)(21)(22)(23)(24) y los resultados obtenidos en esta serie consideramos que este método no convencional de titulación es útil, sencillo, muy económico y aplicable en un entorno en el que debe tenerse especial cuidado con los costos de los procedimientos diagnósticos y terapia. El sistema es una alternativa interesante que puede ser implementado por médicos entrenados en el área de los trastornos respiratorios del sueño.…”

Pressure-Relief Features of Fixed and Autotitrating Continuous Positive Airway Pressure May Impair Their Efficacy: Evaluation with a Respiratory Bench Model

“…Bench studies have been proposed to evaluate the responses of APAP devices in different conditions, such as the presence of predefined sleep disordered breathing (SDB) patterns and air leak, [18][19][20][21][22][23][24][25] whereas no such study to date has focused on pressure-relief CPAPs and APAPs. We investigated seven pressure-relief features developed by three CPAP device manufacturers with a previously reported bench model.…”

Advanced Positive Airway Pressure Modalities

“…Bench studies evaluating the response of different APAP devices to a range of breathing patterns have shown that the responses can be quite variable [7]. A recent bench investigation of eleven APAP devices showed that only five of the devices improved airflow to at least 70 % of baseline breathing amplitude.…”