Newly Published
Perioperative Medicine  |   June 2019
Internal Carotid Artery Blood Flow Response to Anesthesia, Pneumoperitoneum, and Head-up Tilt during Laparoscopic Cholecystectomy
Author Notes
  • From the Division of Physiology, Institute of Basic Medical Sciences (M.S., M.E.), and Institute of Clinical Medicine, Faculty of Medicine (S.S.), University of Oslo, Oslo, Norway; Department of Anesthesia and Intensive Care, Akershus University Hospital, Lørenskog, Norway (S.S.).
  • Submitted for publication August 23, 2018. Accepted for publication May 6, 2019.
    Submitted for publication August 23, 2018. Accepted for publication May 6, 2019.×
  • Correspondence: Address correspondence to Dr. Søvik: Department of Anesthesia and Intensive Care, Division of Surgery, Akershus University Hospital, P.O. Box 1000, 1478 Lørenskog, Norway. signe.sovik@medisin.uio.no. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Ambulatory Anesthesia / Cardiovascular Anesthesia / Gastrointestinal and Hepatic Systems
Perioperative Medicine   |   June 2019
Internal Carotid Artery Blood Flow Response to Anesthesia, Pneumoperitoneum, and Head-up Tilt during Laparoscopic Cholecystectomy
Anesthesiology Newly Published on June 27, 2019. doi:10.1097/ALN.0000000000002838
Anesthesiology Newly Published on June 27, 2019. doi:10.1097/ALN.0000000000002838
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • Cardiac output is an independent regulator of cerebral blood flow in healthy awake humans

  • The relationship between cardiac output and cerebral blood flow in anesthetized patients undergoing laparoscopy has not been previously characterized

What This Article Tells Us That Is New:

  • At steady-state depth of anesthesia, in patients undergoing laparoscopic cholecystectomy, creation of pneumoperitoneum decreased cardiac output and internal carotid artery blood flow while mean arterial pressure and end-tidal carbon dioxide levels remained unchanged

Background: Little is known about how implementation of pneumoperitoneum and head-up tilt position contributes to general anesthesia-induced decrease in cerebral blood flow in humans. We investigated this question in patients undergoing laparoscopic cholecystectomy, hypothesizing that cardiorespiratory changes during this procedure would reduce cerebral perfusion.

Methods: In a nonrandomized, observational study of 16 patients (American Society of Anesthesiologists physical status I or II) undergoing laparoscopic cholecystectomy, internal carotid artery blood velocity was measured by Doppler ultrasound at four time points: awake, after anesthesia induction, after induction of pneumoperitoneum, and after head-up tilt. Vessel diameter was obtained each time, and internal carotid artery blood flow, the main outcome variable, was calculated. The authors recorded pulse contour estimated mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV) index, cardiac index, end-tidal carbon dioxide (ETco2), bispectral index, and ventilator settings. Results are medians (95% CI).

Results: Internal carotid artery blood flow decreased upon anesthesia induction from 350 ml/min (273 to 410) to 213 ml/min (175 to 249; −37%, P < 0.001), and tended to decrease further with pneumoperitoneum (178 ml/min [127 to 208], −15%, P = 0.026). Tilt induced no further change (171 ml/min [134 to 205]). ETco2 and bispectral index were unchanged after induction. MAP decreased with anesthesia, from 102 (91 to 108) to 72 (65 to 76) mmHg, and then remained unchanged (Pneumoperitoneum: 70 [63 to 75]; Tilt: 74 [66 to 78]). Cardiac index decreased with anesthesia and with pneumoperitoneum (overall from 3.2 [2.7 to 3.5] to 2.3 [1.9 to 2.5] l · min−1 · m−2); tilt induced no further change (2.1 [1.8 to 2.3]). Multiple regression analysis attributed the fall in internal carotid artery blood flow to reduced cardiac index (both HR and SV index contributing) and MAP (P < 0.001). Vessel diameter also declined (P < 0.01).

Conclusions: During laparoscopic cholecystectomy, internal carotid artery blood flow declined with anesthesia and with pneumoperitoneum, in close association with reductions in cardiac index and MAP. Head-up tilt caused no further reduction. Cardiac output independently affects human cerebral blood flow.