Administración del clorhidrato de S(+)-ketamina para la dosis test epidural. Comparación con lidocaina y adrenalina.

by Higueras Castellanos, Raquel

ABSTRACT Test dose during epidural anesthesia is essential to avoid intravenous or subarachnoid injection of local anesthetics. There is no agreement on the drug or dose used. Hypothesis: S(+)-ketamine could be useful to detect epidural catheter malposition. We do a two phase study to evaluate the iv (IVPh) and the SA (SAPh) effect of S(+)-ketamine, simulating accidental administration. Material and methods. Ethics committee permission and written informed consent were obtained. Double blinded aleatorized studies. IVPh: Eighty patients, ASA I, aged 18-65 divided into four groups of 20. Simulating an accidental iv administration, 3ml injection of: S+K group, S(+)-ketamine 0.5 mg.kg-1; L5% group, lidocaine 1.5mg.kg-1; ADR, adrenaline 15?g; SF group, physiologic saline. Control for SAP, MAP, DAP, HR, SpO2, and clinical effects at 0, 2, 5, 8, 10, and 15 min after drug injection. SAPh: Fifty-seven patients, ASA I, aged 18-65 divided into three groups of 19. Simulating an accidental SA administration, 3 ml injection of: S+K group, S(+)-ketamine 0.5 mg.kg-1; L5% group, lidocaine 1.5 mg.kg-1; SF group, physiologic saline. Control for SAP, MAP, DAP, HR, SpO2, motor block, sensory block level, and clinical effects at 0, 2, 5, 8, 10, and 15 min after drug injection. Statistics: Chi-square, ANOVA, t-test, sensibility, specificity, predictive positive and negative values were obtained. Significance p<0.05. Results. IVPh: increase in SAP, MAP, DAP and HR (p<0.05) was observed at 2, 5, 8 and 10 min compared to basal in the S+K group only. In this group we chose SAP 5 min increase, showing sensibility 100%, specificity 92%, PPV 93%, NPV 100%. Clinical effects were more frequent in the S+K group (p<0.05) and appeared < 5 min. SAPh: significant decrease in SAP at 2, 5, 8,10 and 15 min was observed in the L5% and S+K groups. Sensory and motor block appeared in the S+K and L5% groups (p<0.05). Clinical effects appeared >10 min after SA injection in the S+K group. Conclussions. During epidural anesthesia S+K 0.5 mg.kg 1 could be a useful marker of both accidental iv (increase of 15 mmHg in SAP at 5 min) or SA (sensory and motor block at 2 min) injection.