Introduction Ultrasound (US) is a useful tool in measuring RFcsa. We have previously shown that a curvilinear ultrasound probe (CUP) is equally effective as a linear ultrasound probe in measuring RFcsa (Mandal et al 2011). We therefore used a CUP-US to characterise the trajectory of muscle loss in a cohort of patients with AECOPD.

Methods Subjects had RFcsa measured at 3/5 of the distance from the anterior superior iliac spine to the superior border of the patella during a hospital admission with AECOPD and at 4 weeks post hospital discharge. Image acquisition was made using real time B-mode ultrasonography using a 2–5MHz curvilinear probe (SonoSite Inc, Japan). RFcsa measurements were calculated offline using the Image J® programme. Subjects also wore an Actiwatch Spectrum device (Phillips Respironics, Murrysville, Pennsylvania) to monitor physical activity levels during exacerbation and recovery.

Results 10 patients were recruited. 40% were male with an age of 71±11years and FEV1 0.6±0.12L (on admission). RFcsa at admission was 519±359mm2. Mean change in RFcsa between admission and follow up was -90±295mm2 (19.5%). Subjects were divided in to 2 groups based on a 10% reduction in RFcsa (see table 1). Small numbers of patients prevented statistical analysis of the data. However, patients with ≥10% RFcsa loss tended to be older, had a lower BMI and longer length of hospital stay. At discharge this group of patients had lower daily physical activity count and greater time spent immobile. Both groups increased their daily activity count and decreased their immobile time between discharge and follow-up. However, those with preserved RFcsa tended to increase their activity count more than those with RFcsa wasting (table 1).

Discussion These data suggest RFcsa muscle wasting as a consequence of an AECOPD was more common in older patients with a lower BMI. These patients tended to have a longer hospital stay with lower activity levels both during and immediately after an AECOPD However, more patients are required to confirm these initial observations.