The plasma concentrations of lidocaine were measured by HPLC(high-performance liquid-chromatography) when 415 mg of 1.5 and 2% plain lidocaine(group 1), carbonated lidocaine(group 2) and lidocaine with epinephrine(group 3) were injected into the caudal spaces of 30 patients. Peak concentrations were achieved 15, 20 and 30 min, after injection in group 1,2 and 3, respectively. The maximum values of mean concentration in group 1,2 and 3 were 3.30+/-0.83, 3.31+/-0.81 and 1.86+/-0.52 ug/ml (mean+/-SD), respectively. The plasma concentration in group 3 were lower than those in groups 1 and 2 at intervals of 5,10,15 and 20 min. However, it was uncertain whether carbonated lidocaine was absorbed more rapidly thus producing significantly higher blood concentrations. The results indicated a significant difference in the plasma concentration of epinephrine-mixed lidocaine from that of plain or carbonated lidocaine. We suggest that in caudal anesthesia, epinephrine(1:200,000) with lidocaine has an advantage with respect to lowering the plasma concentration of lidocaine.
Anesthesia, Caudal* ; Carbon ; Humans ; Lidocaine* ; Plasma*

Pulse oximetry is a relatively new and noninvasive technique for measuring O2 saturation continuously. We applied pulse oximetry to 9 pediatric patients with tetralogy of Fallot during shunt surgery. Arterial blood gas tensions were measured at the time of postinduction, just before insertion of the shunt, after the shunt and at the end of the operation. The SaO2 levels by blood gas analysis were compared with the SpO2 levels as measured by pulse oximetry. SaO2 and SpO2 levels increased after the shunt and at the end of the operation in comparison with before the shunt, but the PaO2 level remained the same in each period. The SaO2 and SpO2 levels were identical in all 4 periods. The pH increased at the end of the operation in comparison with the postinduction. In conclusion, continuous monitoring of SpO2 through pulse oximetry, instead of PaO2 is a very useful method to assess the adequacy of perfusion after the shunt. Pulse oximetry is also a valuable tool with which to choose the site of the pulmonary artery to be shunted.
Blood Gas Analysis ; Humans ; Hydrogen-Ion Concentration ; Oximetry* ; Perfusion ; Pulmonary Artery ; Tetralogy of Fallot*

BACKGROUND: Paraplegia is a devastating complication following operations on the thoracoabdominal aorta. We investigated whether histidine-tryptophan-ketoglutarate (HTK) solution could reduce the extent of ischemia/reperfusion (IR) spinal cord injuries in a rat model using a direct delivery method. METHODS: Twenty-four Sprague-Dawley male rats were randomly divided into four groups. The sham group (n=6) underwent a sham operation, the IR group (n=6) underwent only an aortic occlusion, the saline infusion group (saline group, n=6) underwent an aortic occlusion and direct infusion of cold saline into the occluded aortic segment, and the HTK infusion group (HTK group, n=6) underwent an aortic occlusion and direct infusion of cold HTK solution into the occluded aortic segment. An IR spinal cord injury was induced by transabdominal clamping of the aorta distally to the left renal artery and proximally to the aortic bifurcation for 60 minutes. A neurological evaluation of locomotor function was performed using the modified Tarlov score after 48 hours of reperfusion. The spinal cord was harvested for histopathological and immunohistochemical examinations. RESULTS: The spinal cord IR model using direct drug delivery in rats was highly reproducible. The Tarlov score was 4.0 in the sham group, 1.17±0.75 in the IR group, 1.33±1.03 in the saline group, and 2.67±0.81 in the HTK group (p=0.04). The histopathological analysis of the HTK group showed reduced neuronal cell death. CONCLUSION: Direct infusion of cold HTK solution into the occluded aortic segment may reduce the extent of spinal cord injuries in an IR model in rats.
Animals ; Aorta ; Cell Death ; Constriction ; Humans ; Male ; Methods ; Models, Animal ; Neurons ; Neuroprotective Agents* ; Paraplegia ; Rats ; Rats, Sprague-Dawley ; Renal Artery ; Reperfusion ; Reperfusion Injury ; Spinal Cord Injuries* ; Spinal Cord*