• Lars M Pedersen, Jonas Nielsen, Morten Østergaard, Eigil Nygård, and Henning B Nielsen.
• Department of Anaesthesia, Hvidovre Hospital, Hvidovre, Denmark. larsmoellerp@gmail.com
• Clin Physiol Funct Imaging. 2012 Sep 1; 32 (5): 367-71.

BackgroundCerebral 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.MethodsIntrathoracic pressure was increased to 40 cm H(2)O 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.ResultsThe lung recruitment manoeuvre increased arterial O(2) 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.ConclusionsA 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.© 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

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