Effect of plasma alpha1-acid glycoprotein concentration on the accumulation of lidocaine metabolites during continuous epidural anesthesia in infants and children.
OBJECTIVE
Alpha1-acid glycoprotein (AAG) is an acute-phase protein that is responsible for binding basic drugs such as lidocaine (LDC). The effect of AAG on the duration of LDC during continuous epidural anesthesia in infants and young children was investigated.


METHODS
Plasma levels of LDC and its active metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), were monitored in 20 infants and children, 5 months to 6 years of age, who received continuous epidural infusion of 2.5 mg kg(-1) LDC hourly during abdominal or thoracic surgeries.


RESULTS
Plasma LDC concentrations were constant after the first hour of injection. In contrast, the concentrations of MEGX and GX increased continuously during epidural infusion in all patients. The plasma AAG concentration correlated significantly (r = 0.814, p<0.001) with the steady-state LDC level. In addition, significant inverse correlation was observed between the plasma AAG concentration and the accumulation rate of MEGX (r = 0.742, p = 0.002). The plasma AAG concentration and the accumulation rate of GX correlated weakly (r = 0.474, p = 0.035). There was no correlation between the age of the patient and the plasma AAG concentrations (r = 0.295, p = 0.206).


CONCLUSIONS
Our results suggest that the plasma AAG concentration is a valuable index in preventing the toxicity caused by accumulation of MEGX during continuous epidural anesthesia of LDC.
Kakiuchi
Y
Y
Department of Pharmacy, University of Tsukuba Hospital, Ibaraki, Japan.
Kohda
Y
Y
Miyabe
M
M
Momose
Y
Y
D000767:Anesthesia, Epidural / Q000379:methods*; D000779:Anesthetics, Local / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008012:Lidocaine / Q000031:analogs & derivatives* / Q000097:blood*; D008297:Male; D009961:Orosomucoid / Q000378:metabolism*; D011485:Protein Binding
D000779:Anesthetics, Local; D009961:Orosomucoid; D008012:Lidocaine; C001306:glycinexylidide; C001173:monoethylglycinexylidide