Defining Hypotension during Anesthesia: Reply

We wish to thank Drs. Roth¹  and Gross²  for pointing out a typographical error in our recent Clinical Focus Review in Anesthesiology.³  In the next to last paragraph of that review we erroneously stated that 1.35 mmHg should subtracted from blood pressure measured at the heart level for each 1 cm of head elevation, such as with “beach chair” patient positioning. The aim of that subtraction is to obtain an estimate of the blood pressure at the Circle of Willis as widely discussed.⁴  We meant this sentence to read: 1 mmHg should be subtracted from the blood pressure measured at heart level for each 1.35 cm of head elevation, or more precisely, 0.74 mmHg for each 1 cm of head elevation.

This work was funded in part by National Institutes of Health grant No. R01HL092259 (Bethesda, Maryland; to Dr. Hogue).

Dr. Hogue has served as a consultant and provide lectures for Medtronic, Inc, (Minneapolis, Minnesota) and Edwards Lifescience (Irvine, California), and indicates a financial relationship with Merck, Inc. (DSMB, Sugamadex).