Reliability of Apnea-Hypopnea Index Measured by a Home Bi-Level Pressure Support Ventilator Versus a Polysomnographic Assessment

Abstract

BACKGROUND: Ventilators designed for home care provide clinicians with built-in software that records items such as compliance, leaks, average tidal volume, total ventilation, and indices of residual apnea and hypopnea. Recent studies have showed, however, an important variability between devices regarding reliability of data provided. In this study, we aimed to compare apneahypopnea indices (AHI) provided by home ventilators (AHI NIV ) versus data scored manually during polysomnography (AHI PSG ) in subjects on noninvasive ventilation (NIV) for obesity-hypoventilation syndrome. METHODS: Stable subjects with obesity-hypoventilation syndrome on NIV, all using the same device, underwent 3 consecutive polysomnographic sleep studies with different backup breathing frequencies (spontaneous mode, low and high backup breathing frequencies). During each recording, AHI NIV was compared with AHI PSG . RESULTS: Ten subjects (30 polysomnogram tracings) were analyzed. For each backup breathing frequency (spontaneous mode, low and high backup breathing frequencies), AHI values were 62 ؎ 7/h, 26 ؎ 7/h, and 17 ؎ 5/h (mean ؎ SD), respectively. Correlation between AHI NIV and AHI PSG was highly significant (r 2 ‫؍‬ 0.89, P < .001). As determined by Bland-Altman analysis, mean bias was 6.5 events/h, and limits of agreement were ؉26.0 and ؊12.9 events/h. Bias increased significantly with higher AHI values. Using a threshold AHI value of 10/h to define appropriate control of respiratory events, the ventilator software had a sensitivity of 90.9%, a specificity and positive predictive value of 100%, and a negative predictive value of 71%. CONCLUSIONS: In stable subjects with obesity-hypoventilation syndrome, the home ventilator software tested was appropriate for determining if control of respiratory events was satisfactory on NIV or if further testing or adjustment of ventilator settings was required. (ClinicalTrials.gov registration NCT01130090.)

Monitoring Noninvasive Ventilation in Patients with Obesity Hypoventilation Syndrome: Comparison between Ventilator Built-in Software and Respiratory Polygraphy

“…A p value of <0.05 was considered significant. As only one recent cohort study [12] evaluated the reliability of events provided by the BIS as compared with PSG and it only included 10 patients, it was not possible to calculate a sample size on the basis of published data.…”

“…The interrater agreement of scoring respiratory events on both Reslink and PG between operators was determined by Cohen's kappa coefficient [15] . Recordings were dichotomously categorized as "normal" ( ≤ 10 events/hour) or "abnormal" (>10 events/hour) [12] . Differences between automatically and manually scored EI from both Reslink and PG were assessed using the Student t test.…”

“…Nevertheless, few studies have evaluated such software programs in patients on NIV [10][11][12] . Moreover, their reliability may be challenged because of the complex nature of abnormal respiratory events occurring during bilevel positive airway pressure ventilation, which may not comply with standard definitions of nocturnal respiratory events in spontaneous breathing [13,14] .…”

Long-Term Ventilation in Neuromuscular Patients: Review of Concerns, Beliefs, and Ethical Dilemmas

“…In a study on stable subjects with obesity-hypoventilation syndrome, the BIS tested by the authors provided a reliable AHI compared to the PSG [73]. …”

And the Doctor Answers: “Dream, Dream, I Will Be the Guardian of Your Breathing…”

“…Recent studies have demonstrated their reliability and suggested their interest in clinical practice. [13][14][15] By providing an evaluation of ''critical signals'' involved in NIV effectiveness (i.e., arterial oxygen saturation, leaks, estimated minute ventilation and tidal volume) such systems provide very useful information for assessing quality of ventilation. 15 Some software systems allow a breath by breath evaluation of flow and pressure proposing raw signals close to those provided by PG/ PSG.…”