Chnrcal Nurritiun ( 1994) 13: 265-266

0 Longman Group Ltd 1994

Correspondence

Sir, Optimal Hickman catheter tip placement by trans- catheter continuous pressure wave form monitoring

The Hickman silicone catheter and subcutaneous port

devices are widely used as a chronic venous access for pro- longed parenteral nutrition, chemotherapy administration and in bone marrow transplant recipients.

Although Dr Hickman relates to the catheter bearing his name as a ‘right atria1 catheter’, he emphasizes that the insertion technique should place the tip of the catheter at the lower portion of the superior vena cava at its entrance to the right atrium (1). Catheter tips that extend into the atrium may impinge on the endocardium impeding blood aspiration. (2)

The location of the catheter tip and correct placement during the insertion procedure is facilitated by the use of an image intensifier ( 1, 3). This technique lacks accuracy in demonstrating the caval-atria1 junction due to magnification and angulation distortions. (4)

In order to increase the accuracy of the catheter tip place- ment, we describe a method of continuous right sided pres- sure wave form recordings through the Hickman catheter in conjunction with an image intensifier.

Under local anesthesia with the patient in mild Trendelenburg position the subclavian vein is punctured with a needle and syringe through which a guide wire is inserted into the superior vena cava. as described elsewhere (5), until an arrythmia is elicited. The silicone catheter is introduced through the peel away sheath and the pressure wave form recording is initiated via a three way stop-cock connecting the proximal end of the catheter to a pressure transducer. The catheter tip position is monitored by observ- ing the wave form characteristics until properly placed at the caval-atria1 junction (Fig.) Routine fixation completes the procedure. Post-procedure chest X-rays confirm correct positioning.

This method is based upon the fact that silicone catheters have a soft wall, facilitating prolonged catheterization but causing inadequate damping of measured pressure waves due to the low natural frequency resonance of soft wall cath- eters (6). The lack of adequate damping produces distor- tions or ‘noise’ in the right pressure recordings. The amount and amplitude of these distortions are maximal in the right atrium close to the tricuspid valve and decrease as the catheter is pulled back into the superior vena cava. The caval-atria1 junction is recognized by the sudden drop in quantity and amplitude of ‘noise’ in the central venous pressure wave form.

After gaining experience with the combined fluoroscopy - pressure wave recording method of catheter tip placement, we have successfully used pressure wave form recordings as the sole method of silicone catheter tip placement when fluoroscopy was unavailable.

Fig. Scale 2:3. Tramcatheter right sided pressure wave form recordings. Paper speed = 2.5 mm/s, Scale 1 cm = 5 torr. R. V. - Right ventricular pressure recording. R. A. T. - Right atrial pressure recording close to tricuspid valve. R. A. S. - Right atrial pressure recording close to the caval-atria1 junction. S. V. C. - Superior vena cava pressure recording.

This technique is a safe operative alternative for periph- eral hospitals or ambulatory surgical (day-care) facilities which lack a reliable and expensive image-intensifier.

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266 CORRESPONDENCE

References

1. Hickman R D, Buckner C D, Clift R A. A modified right atria1 catheter for access to the venous system in marrow transplant recipients. Surg Gynecol Obstet 1979: 148: 871.

2. Reed W P, Newman K A, De Jongh C. Prolonged venous access for chemotherapy by means of the Hickman catheter. Cancer 1983; 52: 185.

3. Pollack P F. Kadden M, Byrne W J. 100 Patient Year’s experience with the Broviac silastic catheter for central venous nutrition. JPEN 1981; 5: 32.

4. Leinhardt D J, Carlson G L, O’Hanrahan T, Mamtora H, Brown K, Irving M H. Assessment of central venous feeding catheter position. Intraoperative screening or postoperative radiography? Clin Nutr 1993; 12 (Suppl. 2): P. 60.

5. Hawkins J, Nelson E W. Percutaneous placement of Hickman

catheters for prolonged venous access. Am J Surg 1982; 144: 624.

6. Barry W H. Grossman W. Cardiac Catheterization. In: Braunwald E, ed. Heart Disease, A Textbook of Cardiovascular Medicine. Philadelphia: W. B. Saunders, 1984: 279.

Benjamin Hoffman*, Zvi Gimmon,

Department of Anesthesiology*, Department of General Surgery,

Hadassah-Hebrew University Medical Center, Ein - Kerem,

Jerusalem, 91120 Israel.

Reprint requests to ZG

Submission date: 31 January 1994; Acceptance date: 1 March 1994