Increased intrathoracic pressure affects cerebral oxygenation following cardiac surgery

TY - JOUR

T1 - Increased intrathoracic pressure affects cerebral oxygenation following cardiac surgery

AU - Pedersen, Lars M

AU - Nielsen, Jonas

AU - Østergaard, Morten

AU - Nygård, Eigil

AU - Nielsen, Henning B

N1 - © 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

PY - 2012/9

Y1 - 2012/9

N2 - Background: Cerebral oximetry reflects circulatory stability during surgery. We evaluated whether frontal lobe oxygenation is influenced by a transient increase in intrathoracic pressure as induced by a lung recruitment manoeuvre. Methods: Intrathoracic pressure was increased to 40 cm H2O for 20 s immediately after cardiac surgery in ten patients (age 64 ± 10 year, mean ± SD) with frontal lobe oxygenation assessed by near-infrared spectroscopy and cardiac output by thermodilution. Results: The lung recruitment manoeuvre increased arterial O2 pressure (from 29 ± 15 to 40 ± 12 kPa) with a decrease in mean arterial pressure (MAP) (from 69 ± 7 to 55 ± 11 mmHg), cardiac output (from 5·4 ± 0·6 to 5·0 ± 0·7 l min-1) and frontal lobe oxygenation (from 68 ± 9 to 60 ± 13%; all P<0·05). A reduction in MAP by more than 15 mmHg caused cerebral desaturation by 10%, the lowest cerebral oxygenation (44%) was with a reduction in MAP by 24 mmHg, and according to multiple linear regression, only MAP predicted cerebral deoxygenation (P = 0·03). Following the lung recruitment manoeuvre, hemodynamic variables and frontal lobe oxygenation were restored. Conclusions: A lung recruitment manoeuvre decreases frontal lobe oxygenation when MAP is low suggesting that with increased intrathoracic pressure, arterial pressure should be kept within the limits of cerebral autoregulation.

AB - Background: Cerebral oximetry reflects circulatory stability during surgery. We evaluated whether frontal lobe oxygenation is influenced by a transient increase in intrathoracic pressure as induced by a lung recruitment manoeuvre. Methods: Intrathoracic pressure was increased to 40 cm H2O for 20 s immediately after cardiac surgery in ten patients (age 64 ± 10 year, mean ± SD) with frontal lobe oxygenation assessed by near-infrared spectroscopy and cardiac output by thermodilution. Results: The lung recruitment manoeuvre increased arterial O2 pressure (from 29 ± 15 to 40 ± 12 kPa) with a decrease in mean arterial pressure (MAP) (from 69 ± 7 to 55 ± 11 mmHg), cardiac output (from 5·4 ± 0·6 to 5·0 ± 0·7 l min-1) and frontal lobe oxygenation (from 68 ± 9 to 60 ± 13%; all P<0·05). A reduction in MAP by more than 15 mmHg caused cerebral desaturation by 10%, the lowest cerebral oxygenation (44%) was with a reduction in MAP by 24 mmHg, and according to multiple linear regression, only MAP predicted cerebral deoxygenation (P = 0·03). Following the lung recruitment manoeuvre, hemodynamic variables and frontal lobe oxygenation were restored. Conclusions: A lung recruitment manoeuvre decreases frontal lobe oxygenation when MAP is low suggesting that with increased intrathoracic pressure, arterial pressure should be kept within the limits of cerebral autoregulation.

KW - Aged

KW - Arterial Pressure

KW - Cardiac Output

KW - Cardiac Surgical Procedures

KW - Cardiopulmonary Bypass

KW - Cerebrovascular Circulation

KW - Denmark

KW - Frontal Lobe

KW - Homeostasis

KW - Humans

KW - Hypotension

KW - Linear Models

KW - Lung

KW - Middle Aged

KW - Multivariate Analysis

KW - Oximetry

KW - Oxygen

KW - Respiratory Physiological Phenomena

KW - Spectroscopy, Near-Infrared

KW - Thermodilution

KW - Thoracic Cavity

KW - Time Factors

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1111/j.1475-097x.2012.01138.x

DO - 10.1111/j.1475-097x.2012.01138.x

M3 - Journal article

C2 - 22856343

SN - 1475-0961

VL - 32

SP - 367

EP - 371

JO - Clinical Physiology and Functional Imaging

JF - Clinical Physiology and Functional Imaging

IS - 5

ER -