A simple diagnostic test to confirm correct placement of intravenous catheters before chemotherapy.

Purpose: To determine the feasibility and effectiveness of using a single injection of diluted sodium bicarbonate, while monitoring exhaled carbon dioxide changes, to reliably confirm correct placement of intravenous (IV) catheters.

Methods: The study was conducted in the oncology day care clinic at a tertiary care center and included a selected group of patients with various oncological conditions who required IV chemotherapy. In each patient a newly inserted peripheral IV catheter or newly accessed central line was deemed positively intravascular if they had good blood return or most probably intravascular if there was no blood return but they flushed easily. This clinical diagnosis of correct positioning, was correlated with the results of a single injection of dilute sodium on the exhaled carbon dioxide, and with the ability of a blinded observer to report whether sodium bicarbonate or saline was injected.

Results: A total of 67 patients were enrolled in the study; 56 had positively intravascular IV catheter while 11 had most probably intravascular IV catheter. A single injection of 20 mL 4.2% sodium bicarbonate had a positive and clinically detectable response that was diagnosed with high sensitivity and specificity.

Conclusions: IV injection of 20 mL of 4.2% sodium bicarbonate with exhaled carbon dioxide monitoring can be used to reliably confirm correct intravascular placement of a catheter intended to be used for chemotherapy.