Multiple organ failure (MOF) is accompanied by muscle wasting, but changes in body composition are frequently obscured by fluid retention (edema), mainly in superficial and visceral tissue. There is a need to assess body composition and changes in body composition in these circumstances independently of edema. A relation was sought between fat-free (lean tissue) mass [calculated from body weight and skinfold thicknesses and measured by using dual-energy X-ray absorptiometry (DXA)] and muscle thickness (measured using ultrasound at a variety of sites accessible in an unconscious supine subject) to determine which sites correlated best with lean body mass. The three best sites were midbiceps, midforearm anteriorly, and midthigh anteriorly: R2 for the simple sum of the three sites correlated with fat-free mass from skinfold thicknesses was 71.1%, and with lean tissue mass from DXA was 76.1%. Serial measurements of both muscle thickness and midupper-arm circumference in nine patients with MOF showed a complete dissociation; in all nine there was a significant negative correlation of muscle thickness with time (P < 0.05) but changes in arm circumference were random. Only one patient showed a significant negative correlation with time, seven showed no change, and one other showed a significant increase. The muscle thicknesses that correlate best with lean body mass are measured over the biceps, anterior forearm, and anterior thigh. Monitoring muscle thicknesses at these three sites identifies wasting in edematous patients as it is happening.

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100 consecutive patients underwent digital subtraction aortic arch angiography for suspected carotid bifurcation disease. Patients were prospectively randomized to suspend respiration in inspiration or expiration during image acquisition. Images were assessed qualitatively as "excellent", "adequate" or "poor". 92 studies were available for review. Adequate and poor groups were combined into a non-excellent group due to the small numbers that were scored poor. There were 27 (53%) excellent, 24 (47%) non-excellent in the expiration group and 12 (29%) excellent, 29 (71%) non-excellent in the inspiration group. Analysis of angiogram scores gave chi 2(1) = 4.3; p = 0.038, indicating that the higher angiogram scores of the expiration group were statistically significant. Pixel shifting was used in 61 cases (66.3%). The proportion was 34.4% lower in the expiration group (95% CI; 17-52%) with chi 2(1) = 10.5; p = 0.0012 indicating that the reduction in the use of pixel shifting for the expiration group was statistically significant. The superiority of arch angiograms obtained with the patient suspending respiration in expiration rather than inspiration has been demonstrated. This was achieved with significantly reduced use of pixel shifting, encouraging greater confidence in the validity of the angiographic findings. The technique is free of cost or time implications.

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