Peripheral intravenous waveform analysis - a novel tool to confirm intravascular catheter placement

Peripheral intravenous (IV) catheter infiltration is a common complication which can cause harmful extravasation of fluid and medications. Significant injury can occur before standard infusion pumps detect a threshold pressure. Peripheral IV waveform analysis (PIVA) uses fast Fourier transform (FFT) to measure the amplitude of the venous waveform. This study aims to evaluate if PIVA can differentiate between IV catheter positions, primarily intravenous versus subcutaneous, in a rat model. Surgical cutdown was performed on the right proximal saphenous vein. Pressure and waveforms were recorded from a 22G IV catheter open-to-air, in the vein, and in the adjacent subcutaneous (SC) tissue. Measurements were performed at baseline and after injection of 1 mL Plasmalyte and are reported as median (interquartile range). The peak amplitude corresponding to the heart rate frequency labeled as f1. Pre-flush intravascular f1, 0.0824 mmHg (IQR 0.0256, 0.1480), differed significantly from both SC, 0.0001 mmHg (0.0000, 0.0004), and open-to-air, 0.0001 mmHg (0.0000, 0.0008), conditions, ANOVA p = 0.03, pairwise p = 0.049 and 0.049, respectively. These significant differences remained after flush. Post-flush pressures between IV, 7.9 mmHg (6.6, 8.9) and SC, 20.5 mmHg (11.3, 28.8) were significantly different, p = 0.0001. There was no significant difference in pre-flush and post-flush pressure within IV, SC, and open-air groups, p = 0.687, p = 0.110 and p = 0.219, respectively. PIVA was superior to absolute pressure measurement for detecting intravascular versus extravascular placement of an IV catheter. This study demonstrates utility of PIVA as a novel method for confirming proper IV placement.