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The relationship between hypotension, cerebral flow, and the surgical field during endoscopic sinus surgery
Author(s) -
Ha Thanh Ngoc,
van Renen Robert Graham,
Ludbrook Guy L.,
Valentine Rowan,
Ou Judy,
Wormald PeterJohn
Publication year - 2014
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.24664
Subject(s) - anesthesia , medicine , hemodynamics , mean arterial pressure , blood pressure , transcranial doppler , middle cerebral artery , cerebral blood flow , surgery , heart rate , ischemia , cardiology , radiology
Objectives/Hypothesis Hypotensive anesthesia is often used in endoscopic sinus surgery (ESS) to improve surgical visibility; however, its safety and efficacy in this role are yet to be justified. This study aimed to evaluate the effect of hypotensive anesthesia on both real‐time middle cerebral artery blood flow velocity (Vmca) and the severity of surgical bleeding in patients undergoing ESS. Study Design Prospective, observational cohort study. Methods Thirty‐two patients undergoing hypotensive anesthesia for ESS at a single tertiary institution during February 2011 to July 2012 were recruited for the study. Transcranial Doppler ultrasonography measured periodic Vmca, which were time‐matched for hemodynamic and respiratory factors. One‐minute video segments corresponding with each Vmca reading were randomized and distributed to two blinded observers for bleeding assessment. Results Three hundred and fifty‐six data time points were recorded for systolic, diastolic, and mean arterial blood pressure (MAP), pulse rate, respiratory rate, end‐tidal carbon dioxide concentration, Vmca, and bleeding assessment score (BAS). A direct relationship exists between MAP and Vmca ( r = 0.77, P < .0001) as well as MAP and BAS ( r = 0.36, P < .0001). MAP levels above 60 mm Hg maintained at least 50% of baseline Vmca flow in almost 90% of all time points. Conclusions Hypotensive anesthesia is an effective method of controlling intraoperative bleeding during endoscopic sinus surgery; however the effect is clinically small in low MAP ranges. In otherwise healthy patients undergoing ESS with general anesthesia, reducing MAP to below 60 mm Hg may increase the risk of cerebral ischemia. Level of Evidence 2b Laryngoscope 124:2224–2230, 2014