PT  - JOURNAL ARTICLE
AU  - Ari R Manuel
AU  - Nicholas Hart
AU  - John R Stradling
TI  - Correlates of obesity-related chronic ventilatory failure
AID  - 10.1136/bmjresp-2015-000110
DP  - 2016 Feb 01
TA  - BMJ Open Respiratory Research
PG  - e000110
VI  - 3
IP  - 1
4099  - http://bmjopenrespres.bmj.com/content/3/1/e000110.short
4100  - http://bmjopenrespres.bmj.com/content/3/1/e000110.full
SO  - BMJ Open Resp Res2016 Feb 01; 3
AB  - Introduction Only a third of obese patients develop chronic ventilatory failure. This cross-sectional study assessed multiple factors potentially associated with chronic ventilatory failure.Materials/patients and methods Participants had a body mass index (BMI) >30 kg/m2, with or without chronic ventilatory failure (awake arterial partial pressure of carbon dioxide >6 kPa or base excess (BE) ≥2 mmols/L). Factors investigated were grouped into domains: (1) obesity measures, (2) pulmonary function, (3) respiratory and non-respiratory muscle strength, (4) sleep study derivatives, (5) hypoxic and hypercapnic responses, and (6) some hormonal, nutritional and inflammatory measures.Results 71 obese participants (52% male) were studied over 27 months, 52 (SD 9) years and BMI 47 (range 32–74) kg/m2. The best univariate correlates of BE from each domain were: (1) dual-energy X-ray absorptiometry measurement of visceral fat (r=+0.50, p=0.001); (2) supine forced expiratory volume in 1 s (r=−0.40, p=0.001); (3) sniff maximum pressure (r=−0.28, p=0.02); (4) mean overnight arterial oxygen saturation (r=−0.50, p<0.001); (5) ventilatory response to 15% O2 breathing (r=−0.28, p=0.02); and (6) vitamin D (r=−0.30, p=0.01). In multivariate analysis, only visceral fat and ventilatory response to hypoxia remained significant.Conclusions We have confirmed that in the obese, BMI is a poor correlate of chronic ventilatory failure, and the best independent correlates are visceral fat and hypoxic ventilatory response.Trial registration number NCT01380418.