Breathemnd-1 study: a prospective study to systematically assess the nature and time course of sleep disordered breathing and respiratory failure in patients with motor neurone disease

Introduction: Sleep-disordered breathing (SDB) in patients with motor neurone disease (MND) is normally attributed to hypoventilation due to muscle weakness. However, we have observed different patterns of SDB among MND patients referred for non-invasive ventilation, which do not appear to be explained by respiratory muscle weakness alone. Aim: The aim of this study was to examine the characteristics of SDB in MND. Methods: This is a retrospective analysis of sleep studies (using polysomnography [PSG]), pulmonary function tests, and arterial blood gases in MND patients referred to a tertiary sleep medicine service for clinical review. Sleep apnoeas were characterised as obstructive or central, and to further characterise the nature of SDB, hypopnoeas were classified as obstructive versus central. Results: Among 13 MND patients who had a diagnostic PSG, the mean ± SD age was 68.9 ± 9.8 years, BMI 23.0 ± 4.3 kg/m2, forced vital capacity 55.7 ± 20.9% predicted, and partial pressure of CO2 (arterial blood) 52.7 ± 12.1 mm Hg. A total of 38% of patients (5/13) showed evidence of sleep hypoventilation. The total apnoea/hypopnoea index (AHI) was (median [interquartile range]) 44.4(36.2–56.4)/h, with 92% (12/13) showing an AHI >10/h, predominantly due to obstructive events, although 8% (1/13) also showed frequent central apnoea/hypopnoeas. Conclusions: Patients with MND exhibit a wide variety of SDB. The prevalence of obstructive sleep apnoea (OSA) is surprising considering the normal BMI in most patients. A dystonic tongue and increased upper-airway collapsibility might predispose these patients to OSA. The wide variety of SDB demonstrated might have implications for ventilator settings and patients’ outcomes.

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O012 A prospective evaluation of the nature and time course of sleep disordered breathing and respiratory failure in patients with motor neurone disease (MND): the BreatheMND-1 study

SLEEP Advances ◽

10.1093/sleepadvances/zpab014.011 ◽

2021 ◽

Vol 2 (Supplement_1) ◽

pp. A5-A6

Author(s):

V Aiyappan ◽

P Catcheside ◽

N Antic ◽

N Grivell ◽

C Hansen ◽

...

Keyword(s):

Respiratory Failure ◽

Sleep Disordered Breathing ◽

Time Course ◽

Sleep Time ◽

Prospective Evaluation ◽

Arterial Blood Gas ◽

Arterial Blood ◽

Roc Area ◽

Disordered Breathing

Abstract Introduction Sleep disordered breathing (SDB) is a well-recognised but heterogeneous complication in MND and may herald the onset of respiratory failure. This study examined the nature and time course of SDB, sleep disruption and respiratory failure in MND patients. Methods The BreatheMND-1 study recruited MND patients for prospective evaluation of muscle strength,supine and prone dyspnea, quality of life, pulmonary function, arterial blood gas and polysomnographic sleep measurements at baseline and, where possible, 3, 6 and 12 months for exploratory analyses. Results 35 MND patients completed baseline and 25 at least one follow-up visit (median [IQR] follow-up time 8.7 [7.1–10.2] months). At baseline, patients were aged 64 [55–70] years, 16/35 (46%) female, with reduced FVC (77[59–92] %predicted) but relatively normal BMI (26.2[23.7–27.7] kg/m²) and PaCO2 (38.8[37.0–42.1] mmHg). At baseline and last follow-up, the prevalence of respiratory failure (PaCO2>45 mmHg or HCO3>27 mmol/l) was 9/33 (27%) and 12/27 (44%) respectively (p=0.186). Total sleep time and sleep efficiency were poor at baseline (5.2[4.6–5.9] h and 67.6[63.0–78.8]%) and declined at follow-up (by 1[0.3–1.9] h, p=0.020 and 7.9[-2.3–14.2]%, p=0.017 respectively). AHI was 7.2[2.8–14.6] /h and remained unchanged. In regression model,sleep time and efficiency were not predictive of respiratory failure, but the percentage of deep and REM sleep at last follow-up were (ROC area under curve 0.73±0.11, p=0.048 and 0.84±0.09, p=0.001). Discussion Sleep quality in MND is remarkably poor, irrespective of SDB, and could reflect and/or impact MND progression. Thus, further strategies to monitor & improve sleep are clearly warranted in patients with MND.

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