Steps involved and trouble-shooting during chemoport placement: How we do it?

Dear Editor,

We read with interest the letter to the Editor titled ‘Accidental arterial chemoport catheter insertion’ by Bihani et al.[1] The authors described how the guidewire could have entered the artery and been prevented with the use of ultrasound (US). Patients with certain cancer could have enlarged lymph nodes and mediastinal masses, which could distort the anatomy and make the cannulation difficult. Pediatric chemoport placement is even more challenging especially when there are intrathoracic space-occupying lesions.[2] We want to share our institutional protocol used while performing chemoport placement and certain suggestions during difficult cannulation.

We usually perform infraclavicular subclavian vein puncture either using landmark technique or under US and the wire placement at cavoatrial junction is confirmed with fluoroscope [Figure 1a and b]. US can also be used to reposition the wire in case there is a malposition (subclavian vein, internal jugular vein, and coiling).[3] Radiation exposure during chemoport placement is minimal and enhances safety for such procedures.[4] Fluoroscopy is used again during dilatation and lastly after placing the chemoport in the port reservoir after achieving hemostasis. The port is flushed several times with normal saline and lastly locked after injecting heparin lock flush solution. At times, it is difficult to appreciate the great vein on fluoroscopy due to intrathoracic masses causing distortions. To avoid this, we suggest reviewing the scans that the patient has undergone recently (a computed tomography chest or a positron emission tomography scan). Anomalies and distortions will be revealed in that which can alert the clinician well in advance.

Figure 1.

(a) Confirmation of chemoport catheter placement fluoroscopically. (b) Yellow arrow: correct location of guidewire along the right side of vertebral column depicting entry into a great vein. Yellow dots: wire crossing mid-line and seen along the left side of vertebral column suggests entry into an artery. (c) The use of electrocardiography for confirmation of wire in SVC–RA junction. (d) Amplitude of P-wave almost equal to R-wave of ECG in lead II

Electrocardiographic (ECG) guidance can be considered for confirming correct entry of wire into superior vena cava (SVC) and RA in difficult cases. The point at which there is an increase in P-wave size, known as ‘P-atriale’, is considered the proper position of central venous catheter tips. However, it requires special equipment as shown in Figure 1c and 1d. Schummer et al. mentioned that increase in P-wave size need not always correspond with the position into of guidewire at cavoatrial junction.[5] Unfortunately, ECG guidance cannot distinguish between venous and arterial catheter placement.

To conclude, we suggest a pre-procedure review of scans, use of intraoperative US with fluoroscopy and use of ECG guidance in selected cases for chemoport placement. We also recommend a chest radiograph post procedure to confirm port placement, to rule out pneumothorax and as a baseline for subsequent follow-up if deemed necessary.

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