Relative Blood Volume Profiles Hours After Loop Diuretic Administration: A Systematic Review and Meta-analysis

Figures

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  Figure 1. Profiles of relative blood volume change after single loop diuretic dose by baseline congestion status. Each profile is a plot of the average change in blood volume relative to baseline (black horizontal dashed line). The grey horizontal lines at the top of the figure represent periods delineated by the opposing forces of diuresis and plasma refill; these 2 processes act concurrently but slightly out of phase, depending on the degree of interstitial congestion. The profile of solid diamonds that are connected by a dashed line represents 84 subjects with baseline congestion, and the profile of solid circles that are connected by a solid line represents 129 subjects with no baseline congestion. The vertical lines centred on each solid diamond or circle represent 95% confidence intervals generated from a mixed-effects longitudinal meta-analysis (details provided in the text). The profiles are statistically distinct during each follow-up period. Compared to subjects with congestion, subjects without congestion had an average blood volume that was 5.4% lower (1.2% to 9.7%, P = 0.012) in the first 2 hours after diuretic administration, 6.2% lower (0.1% to 12.3%, P = 0.047) in the third…

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  Figure 2. Schematic profiles of relative blood volume used to estimate plasma refill rate. The plasma refill rate can be estimated from cumulative urine output if the relative blood volume profile is known. Three different plasma refill rates are depicted in the schematic; these represent either different patients or different volume states within the same patient. In the top panel, the solid red line represents severe congestion—relative blood volume remains at baseline despite diuresis. The solid yellow line represents intermediate congestion—relative blood volume is initially negative but returns to baseline. The solid green line represents a decongested volume status—relative blood volume is persistently negative throughout follow-up. In the bottom panel, the solid red, yellow, and green lines represent cumulative urine output after a loop diuretic is administered, while the dashed red, yellow, and green lines represent the cumulative plasma refill. The lines are coded to correspond to the relative blood volume profiles in the top panel. In the case of severe congestion (red lines), just a single measurement of cumulative urine output is needed at the first follow-up to generate a…