Thoracic Epidural Catheter Placement in Infants via the Caudal Approach Under Electrocardiographic Guidance: Simplification of the Original Technique

To the Editor: In a previous study published in this journal (1), we proposed the use of electrocardiography (ECG) to guide the tip of an epidural catheter from caudal space to thoracic region. In this prospective study, simultaneous ECG tracings were recorded via the epidural catheter and the target spinal surface ECG using a modified 2-channel 5-lead ECG system with lead II, III mode. This technique required replacing a commonly used standard 3-lead cable with a 5-lead ECG cable, which is not always readily available in pediatric anesthesia. To solve this problem, we have simplified our ECG technique to allow the use of a standard 3-lead ECG (Fig. 1). First, a standard ECG (lead II) is recorded by connecting the right-arm electrode (white) to a skin electrode on the patient’s back at the target spinal level, while the left-arm electrode (black) and left-leg electrode (red) are placed at their standard position. The shape of this initial ECG must be remembered or a hard copy must be taken as a reference for later. Next, the right-arm electrode is connected to the metal hub of the ECG adapter to record a tracing from the epidural catheter. A satisfactory tracing (lead II) is obtained when the epidural catheter is filled with saline allowing the catheter tip to become a unipolar ECG electrode. The catheter is then advanced from the caudal space until the tip reaches the target level as demonstrated by a match between its ECG configuration and the initial surface ECG. Figure 1.: Simplification of the epidural ECG technique.Ban C. H.