A simple diagnostic test to confirm correct intravascular placement of peripheral catheters in order to avoid extravasation.
BACKGROUND
Intravenous catheters are ubiquitous among modern medical management of patients, yet misplaced or tissued cannulas can result in serious iatrogenic injury due to infiltration or extravasation of injectate. Prevention is difficult, and currently few reliable tests exist to confirm intravascular placement of catheters in awake spontaneously breathing patients.


METHODS
Twenty conscious spontaneously breathing healthy volunteers were injected with 50 mL normal saline and 50 mL 4.2%, or 50 mL 2.1%, or 20 mL 4.2% sodium bicarbonate in a random order. A blinded anesthetist observed continuous sampling of exhaled carbon dioxide and was asked to differentiate between the sodium bicarbonate and saline injections. Peak increase in measured exhaled carbon dioxide was also calculated.


RESULTS
Exhaled carbon dioxide increased significantly in participants injected with intravenous sodium bicarbonate. Mean peak increase was 7.4 mm Hg (±2.1 mm Hg) for 50 mL 4.2% sodium bicarbonate, 4.7 mm Hg (±2.5 mm Hg) for 20 mL 4.2% sodium bicarbonate, and 3.5 mm Hg (±1. 8 mm Hg) for 50 mL 2.1% sodium bicarbonate. The blinded observer correctly identified the injection as sodium bicarbonate or normal saline in every instance.


CONCLUSIONS
Intravenous injection of dilute sodium bicarbonate with exhaled carbon dioxide monitoring reliably confirms correct intravascular placement of a catheter. A transient increase of exhaled carbon dioxide by 10% or more is an objective and reliable confirmation of intravascular location of the catheter. We recommend using 20 mL of 4.2% sodium bicarbonate to minimize the mEq dose of sodium bicarbonate required.
Anesthesiology Department, University of Florida, Gainesville, FL, USA.
Ilan
I
Keidan
Anesthesiology Department, University of Florida, Gainesville, FL, USA. Electronic address: asidi@anest.ufl.edu.
Avner
A
Sidi
School of Medicine, Notre Dame University, Sydney, Australia.
Erez
E
Ben-Menachem
Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
Estela
E
Derazne
Anesthesiology Department, Sheba Medical Center, Ramat Gan, Israel.
Haim
H
Berkenstadt
D000328:Adult; D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis*; D002406:Catheterization, Peripheral / Q000009:adverse effects / Q000379:methods*; D045853:Exhalation; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000517:prevention & control*; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D017693:Sodium Bicarbonate / Q000008:administration & dosage*
D002245:Carbon Dioxide; D017693:Sodium Bicarbonate
Catheters; Diagnostic; Extravasation; Intravascular; Intravenous