Journal of cardiothoracic anesthesia
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J Cardiothorac Anesth · Jun 1988
Clinical TrialThe effects of cardiopulmonary bypass on plasma concentrations and protein binding of methohexital and thiopental.
The effects of cardiopulmonary bypass (CPB) on plasma concentrations and protein binding of methohexital and thiopental were studied during continuous infusions in two groups of ten cardiac surgical patients. Patients were administered an infusion regimen designed to produce a stable total plasma concentration at 5 mg/L for methohexital and 10 mg/L for thiopental. Prior to the commencement of CPB the mean (+/-SD) total plasma methohexital concentration was 5.00 +/- 0.69 mg/L. ⋯ The unbound concentration (1.51 +/- 0.21 mg/L) was again unchanged by the onset of CPB, being 1.71 +/- 0.29 mg/L at 75 minutes. Plasma protein binding of both drugs correlated strongly with plasma albumin concentration, which decreased by 40% during CPB. It is concluded that hemodilution caused the reduction in total drug concentration and protein binding at the onset of CPB, but that the decrease in protein binding counteracted the dilution of unbound drug, resulting in a stable unbound concentration throughout CPB, and that this effect may be common for barbiturates.
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J Cardiothorac Anesth · Jun 1988
Randomized Controlled Trial Comparative StudyLocal anesthesia for radial artery cannulation: a comparison of a lidocaine-prilocaine emulsion and lidocaine infiltration.
A topical anesthetic emulsion consisting of a mixture of lidocaine and prilocaine (EMLA) was used in an attempt to reduce the pain associated with radial artery cannulation. Three groups were compared: (1) EMLA applied at least 90 minutes prior to cannulation (EMLA 90); (2) EMLA applied 60 minutes prior to cannulation (EMLA 60); and (3) lidocaine 2% infiltration performed immediately prior to the procedure (infiltration). ⋯ There was no statistically significant difference in pain scores between the EMLA 60 and infiltration groups. Local side-effects of EMLA were negligible.
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J Cardiothorac Anesth · Jun 1988
Clinical TrialTranscutaneous monitors during one-lung ventilation: are they reliable?
During one-lung ventilation, levels of oxygen and carbon dioxide in the blood are commonly assessed by intermittent blood gas sampling. Transcutaneous PO2 (tcPO2) and transcutaneous PCO2 (tcPCO2) have been reported to accurately reflect arterial PO2 (PaO2) and arterial PCO2 (PaCO2) in hemodynamically stable patients. Transcutaneous monitors appear to be ideal for detecting trends toward hypoxia and hypercarbia, conditions that may not be evident when using intermittent blood gas sampling, while pulse oximetry, since it reflects saturation, may not detect hypoxia until it has already occurred. ⋯ In group 1, for PaO2 <100 mmHg, there was no difference in slopes but y-intercepts were significantly different (P < .05). However, transcutaneous indices were significantly different in both groups for PaO2 <100 mmHg and PaO2 >200 mmHg. It is concluded that transcutaneous monitoring is useful to indicate trends in arterial values in some patients, but blood gas analysis is still necessary to verify the reliability of such monitoring.
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J Cardiothorac Anesth · Jun 1988
Comparative StudyPreservation of the ischemic canine myocardium: a comparison of hypothermia, lidoflazine, and ketanserin.
The purpose of this study was to determine whether ketanserin protects the globally ischemic canine heart and whether such protection, if present, is independent of that provided by hypothermia or calcium channel blockade with lidoflazine. Forty mongrel dogs, anesthetized with halothane, were divided into eight groups of five and subjected to one hour of global myocardial ischemia during hypothermic (30 degrees C; groups 1 to 4) or normothermic (37 degrees C; groups 5 to 8) cardiopulmonary bypass (CPB). Dogs in groups 1 and 5 served as controls with respect to prebypass myocardial protective therapy, and received only placebo (a normal saline bolus) prior to CPB. ⋯ Relative odds of survival were increased 110-fold by hypothermia and sevenfold by lidoflazine. Conversely, treatment with ketanserin was associated with an increased likelihood of nonsurvival. It is concluded that, at the doses studied, ketanserin does not protect the canine myocardium against ischemic injury and may exert a detrimental effect when combined with calcium channel blockade in this setting.
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J Cardiothorac Anesth · Jun 1988
Clinical TrialEffect of hypothermia on median nerve somatosensory evoked potentials.
Median nerve somatosensory evoked potentials (SEP) were monitored in ten patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB). Anesthesia was induced and maintained with sufentanil, oxygen, and pancuronium. Esophageal, nasopharyngeal, rectal, and blood temperatures were continuously monitored. ⋯ There was a strong negative correlation between SEP latencies and temperature (except rectal) (r = -.91, P < .001). for cortical latency and esophageal temperature. A decrease in esophageal temperature of 1 degrees C resulted in an increase in SEP latency of 1 ms. There was also a weak positive correlation between evoked potential amplitude and temperature (r = .19) for cortical amplitude and esophageal temperature.