Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2011
Case ReportsThe possible influence of pulmonary arterio-venous shunt and hypoxic pulmonary vasoconstriction on arterial sevoflurane concentration during one-lung ventilation.
Sevoflurane is widely used for its rapid onset and offset due to a lower blood/gas coefficient. However, involuntary movements, tachycardia, and hypertension have been observed in some patients despite a continuing constantly delivered concentration of sevoflurane during 1-lung ventilation (OLV), indicating the possibility of insufficient depth of anesthesia. We observed a temporary but obvious decrease in arterial sevoflurane concentration and pulse oximeter readings in a patient during OLV. This may have resulted in the depth of inhaled anesthesia being insufficient during OLV because the arterial sevoflurane concentration was lower than expected in spite of constantly delivered and inspiratory/expiratory sevoflurane concentrations.
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Anesthesia and analgesia · Feb 2011
Pulse oximeter plethysmographic waveform changes in awake, spontaneously breathing, hypovolemic volunteers.
The primary objective of this study was to determine whether alterations in the pulse oximeter waveform characteristics would track progressive reductions in central blood volume. We also assessed whether changes in the pulse oximeter waveform provide an indication of blood loss in the hemorrhaging patient before changes in standard vital signs. ⋯ These results support the use of pulse oximeter waveform analysis as a potential diagnostic tool to detect clinically significant hypovolemia before the onset of cardiovascular decompensation in spontaneously breathing patients.