Pulse Oximetry during Shunt Surgery in Pediatric Patients with Tetralogy of Fallot / 대한마취과학회지

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.

Plasma Concentrations of Lidocaine Associated with Caudal Anesthesia / 대한마취과학회지

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.