Fig. 2.
A representative example of the aortic occlusion experiment. Mean arterial pressure (MAP) is elevated for the duration of the 5-min occlusion (A), prompting the registered nurse (RN) to infuse sodium nitroprusside (SNP) at the maximum dose of 3 μg · kg−1 · min−1 with both infusion systems (B). Once the aortic occlusion is released, the MAP falls (A), prompting the RN to turn off the SNP infusion (B) and begin norepinephrine (NE) infusion, eventually reaching the maximum dose of 0.5 μg · kg−1 · min−1 in both conditions (C). Approximately 5 min postocclusion, MAP is stabilized within the target range with the small common-volume (V) system (A), and all drug infusion is stopped shortly thereafter (B and C). In this example, MAP is never stabilized within range using the large common-volume system (A), and the RN again infuses SNP at the maximum dose in response to another rise in MAP (B). The time required for the RN to bring MAP back within the target range after occlusion release (t1) for the small common-volume infusion system is shown as an example for clarity.