Cuff and aortic pressure differences during dobutamine infusion: A study of the effects of systolic blood pressure amplification
Received 29 September 2009; accepted 14 December 2009.
Background
Central aortic systolic blood pressures (SBPs) differ from and are preferable to cuff pressures when calculating cardiac work, left ventricular wall stress, and rate-pressure product. Despite the widespread use of dobutamine, differences between aortic and brachial SBP (pulse amplification) and pulse transmission during dobutamine infusion have not been previously studied. This study assessed these differences and used applanated radial pulses with the Sphygmocor (AtCor Medical, Sydney, Australia) device to investigate the effects of dobutamine on arterial pulse transmission and pulse amplification.
Methods
Using a cuff oscillometer, brachial arterial pressures were measured simultaneously with directly recorded aortic pressures at rest and during increasing dobutamine infusion rates in 25 patients. In 15 of those patients, applanated radial pulses were fed into the Sphygmocor device and calibrated in 2 ways to predict aortic pressures.
Results
At peak dobutamine infusion, SBP amplification averaged 14.9 mm Hg, with a maximum difference of 43 mm Hg. When radial artery pulses were calibrated using cuff pressures, the Sphygmocor underestimated the aortic SBP at all dobutamine doses. However, when radial artery pulses were calibrated using the more accurate aortic mean and diastolic BPs, the Sphygmocor accurately predicted the aortic SBP at baseline, but not at the higher dobutamine doses.
Conclusions
Similar to exercise, dobutamine induced cuff SBPs and pulse pressures higher than those measured in the aorta—uncorrected by the cuff-calibrated Sphygmocor. This increasing pulse amplification was explained by the effects of dobutamine on the properties of the conduit arterial walls, on changes in pulse wave velocity, on increasing heart rate, and on reflected waves.
aCardiology Division, Department of Medicine, Upstate Medical University, State University of New York, Syracuse, NY
bBaltimore Washington Medical Center, Glen Burnie, MD
cDepartment of Neuroscience and Physiology, Upstate Medical University, State University of New York, Syracuse, NY
dCentre de Diagnostique et de Therapeutique, Hopital Hotel Dieu, Paris, France
Reprint requests: Harold Smulyan, MD, Upstate Medical University, Department of Medicine–Cardiology Division, 90 Presidential Plaza, Syracuse, NY 13208.
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