Verification of intravenous catheter placement by auscultation--a simple, noninvasive technique.

Background: Verification of proper placement of an intravenous catheter may not always be simple. We evaluated the auscultation technique for this purpose.

Methods: Twenty healthy volunteers were randomized for 18G catheter inserted intravenously either in the right (12) or left arm (8), and subcutaneously in the opposite arm. A standard stethoscope was placed over an area approximately 3 cm proximal to the tip of the catheter in the presumed direction of the vein to grade on a 0-6 scale the murmur heard by rapidly injecting 2 mL of NaCl 0.9% solution. The auscultation was evaluated by a blinded staff anesthesiologist.

Results: All 20 intravenous injection were evaluated as flow murmurs, and were graded an average 5.65 (±0.98), whereas all 20 subcutaneous injections were evaluated as either crackles or no sound, and were graded an average 2.00 (±1.38), without negative results. Sensitivity was calculated as 95%. Specificity and Kappa could not be calculated due to an empty false-positive group.

Conclusions: Being simple, handy and noninvasive, we recommend to use the auscultation technique for verification of the proper placement of an intravenous catheter when uncertain of its position. Data obtained in our limited sample of healthy subjects need to be confirmed in the clinical setting.