Anaesthesia
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Randomized Controlled Trial Clinical Trial
The effects of remifentanil on haemodynamic stability during rigid bronchoscopy.
We examined the effect of remifentanil on the haemodynamic response to rigid bronchoscopy in 22 adult ASA 2-4 patients, randomly allocated to receive 1.0 microg.kg-1 remifentanil over 1 min followed by 0.5 microg.kg-1.min-1 (remifentanil group) or 2.0 microg.kg-1 fentanyl followed by a saline infusion (control group). Following the initial infusion, all patients received a sleep dose of propofol followed by rocuronium 0.6 mg.kg-1 and their lungs were ventilated using a Sander's injector attached to the rigid bronchoscope. ⋯ Remifentanil attenuated the haemodynamic response to bronchoscopy (p < 0.05 for increases in arterial pressures and heart rate). Four patients in the remifentanil group had ST segment depression compared with eight patients in the control group, but this was not statistically significant.
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The arterial tourniquet is widely used in upper and lower extremity surgery and in intravenous regional anaesthesia. The local and systemic physiological effects and the anaesthetic implications are reviewed. ⋯ Systemic effects are related to the inflation or deflation of the tourniquet. Safe working guidelines for the application of an arterial tourniquet have not been clearly defined.
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Comparative Study
Arterial flow waveforms from pulse oximetry compared with measured Doppler flow waveforms apparatus.
This study compared derived arterial flow waveforms, extracted from pulse oximeter waveforms, with Doppler flow waveforms. Fingertip pulse oximeter waveforms and radial artery Doppler flow waveforms were measured simultaneously in volunteers. The pulse oximeter waveforms were processed to extract the arterial flow waveforms and these were compared with the measured Doppler waveforms. They were very similar.