This article is part of Pulmonology Advisor‘s coverage of the CHEST 2019 meeting, taking place in New Orleans, LA. Our staff will report on medical research related to asthma, COPD, critical care medicine, and more conducted by experts in the field. Check back regularly for more news from CHEST 2019.


NEW ORLEANS — Severe obesity is linked to greater likelihood of having acute respiratory distress syndrome (ARDS), but also underuse of low tidal volume ventilation (LTVV), according to research presented at the CHEST Annual Meeting, held October 19 to 23, 2019, in New Orleans, Louisiana.

Researchers conducted a retrospective analysis of data from 1129 patients at an intensive care unit to investigate whether increased body mass index (BMI) complicated the diagnosis of ARDS or affected use of LTVV, defined as ≤6.5 cc/kg ideal body weight. Diagnosis of ARDS was determined as positive if patients met all Berlin ARDS criteria, indeterminate if they met all criteria but had an indeterminate chest X-ray, or negative if neither X-ray results nor criteria applied. The investigators also examined medical records for ARDS recognition and lowest tidal volume used during ventilation.

Women were more likely to be obese compared with men (44% vs 31%; P <.001), and patients with severe obesity (class 2 and 3) tended to be younger (61 years vs 65 years [P =.004] in lower-BMI groups). Incidence of ARDS was 39% overall and was elevated in patients with class 3 obesity (52%; P =.05). The likelihood of having ≥1 indeterminate chest X-ray was also higher in patients with obesity.

Recognition of ARDS by clinicians was low (45%), regardless of BMI (P =.9), and was associated with greater use of LTVV compared with unrecognized ARDS (74% vs 52%; P <.001). Increasing BMI was associated with decreased LTVV use in all patients classified as having ARDS (73% in underweight, 69% in normal weight, 62% in overweight, 64% in class 1 obesity, 52% in class 2 obesity, and 50% in class 3 obesity; P =.004 for trend). The same pattern was seen in cases of clinician-recognized ARDS (82% in underweight, 85% in normal weight, 78% in overweight, 69% in class 1 obesity, 74% in class 2 obesity, and 50% in class 3 obesity; P =.02 for trend).

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Overall, ARDS was underrecognized in the study population across all BMI categories, but this underrecognition did not explain why patients with class 3 obesity were more likely to meet ARDS criteria but not receive LTVV.

“One possible explanation is that clinicians are using actual rather than ideal body weight for obese patients,” the researchers wrote.

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Reference

Yang K, Gong M. Increased BMI is associated with underutilization of low tidal volume ventilation in patients with ARDS. Presented at: CHEST Annual Meeting 2019; October 19-23, 2019; New Orleans, LA. Abstract 428.