We appreciate the concerns raised in Gologorsky et al.
's correspondence regarding our report of intraoperative radial invasive (ABP) versus
brachial noninvasive (NIBP) blood pressure monitoring.1
We acknowledged in our discussion that there could be debate about which is the “real” pressure we should base clinical decisions upon and presented arguments for both, but offered no recommendation other than to consider both sources of data. As a global test of potential harm, we analyzed some short-term outcomes for those who did and did not have NIBP monitoring and did not find significantly worse outcomes for those who had NIBP monitoring (and its associated fewer transfusions or vasopressor uses). We agree that it would be valuable to do further study of the risks/benefits of withholding therapy, but there are already substantial data to suggest that transfusion, for whatever reason, may lead to worse outcomes and that avoidance of transfusion may be a safer alternative in the perioperative setting.2
We also recognize that NIPB and ABP are completely different technologies. Our data, however, not only compared invasive versus
noninvasive modalities, but radial versus
brachial sites as well. Brachial pressure may be closer to central pressure than radial pressure because radial pressure may sometimes reflect loss of vascular tone in the hand rather than indicating central hypotension. In order to test for this phenomenon in the setting of low ABP and higher NIBP, a wrist compression test has been suggested that will reportedly increase radial pressure closer to central pressure without overshooting.3
Had we used axillary ABP data, our results may have been very different, because our impression is that differences between brachial NIBP and axillary ABP are less than those found in our study. Finally, our patients were in a perioperative setting and not necessarily critically ill, intensive care unit patients in whom much of the data raising concerns about NIBP monitoring have been focused on.
David B. Wax, M.D.,* Andrew B. Leibowitz, M.D. *Mount Sinai School of Medicine, New York, New York. firstname.lastname@example.org