Alterations in skin microcirculation induced by brachial plexus block can be evaluated by wavelet transform of the laser Doppler flowmetry signal. Brachial plexus block reduces the oscillatory components within the 0.0095- to 0.021- and 0.021- to 0.052-Hz intervals of the perfusion signal. These alterations are related to inhibition of sympathetic activity and a possible impairment of endothelial function.
Anesthesiology. 105(3):478-484, September 2006.
Saturday, February 5, 2011
in one-lung ventilation (OLV), shunt fraction increases, oxygenation is impaired, and hypoxemia may occur
When switching from two-lung to one-lung ventilation (OLV), shunt fraction increases, oxygenation is impaired, and hypoxemia may occur. Hypoxemia during OLV may be predicted from measurements of lung function, distribution of perfusion between the lungs, whether the right or the left lung is ventilated, and whether the operation will be performed in the supine or in the lateral decubitus position. Hypoxemia during OLV may be prevented by applying a ventilation strategy that avoids alveolar collapse while minimally impairing perfusion of the dependent lung. Choice of anesthesia does not influence oxygenation during clinical OLV. Hypoxemia during OLV may be treated symptomatically by increasing inspired fraction of oxygen, by ventilating, or by using continuous positive airway pressure in the nonventilated lung. Hypoxemia during OLV may be treated causally by correcting the position of the double-lumen tube, clearing the main bronchi of the ventilated lung from secretions, and improving the ventilation strategy.
Hypoxemia during One-lung Ventilation: Prediction, Prevention, and Treatment
Hypoxemia during One-lung Ventilation: Prediction, Prevention, and Treatment
Anesthesiology. 110(6):1402-1411, June 2009.
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