The epidural test dose in obstetric anesthesia: it is not obsolete.

Many anesthesiologists have called for the abandonment of the epidural test dose in the obstetric patient, citing its lack of sensitivity and specificity. A test dose of lidocaine 1.5% with epinephrine 1:200,000, in combination with aspiration, is highly effective in detecting incorrect placement of an epidural catheter. If the catheter is intrathecal, it requires approximately 2 minutes to obtain a sensory level. For the detection of an intravascular catheter, a positive test dose would result in a sudden increase in the maternal heart rate of 10 beats per minute within 1 minute after injection. It should not be administered during uterine contraction, as labor pain may trigger a tachycardic response. This test dose has been extensively studied and is safe both for both mother and fetus.