Assessing the influence of risk factors on rates and dynamics of peripheral vein phlebitis: an observational cohort study.

BACKGROUND AND OBJECTIVES To assess the influence of risk factors on the rates and kinetics of peripheral vein phlebitis (PVP) development and its theoretical influence in absolute PVP reduction after catheter replacement. METHODS All peripheral short intravenous catheters inserted during one month were included (1201 catheters and 967 patients). PVP risk factors were assessed by a Cox proportional hazard model. Cumulative probability, conditional failure of PVP and theoretical estimation of the benefit from replacement at different intervals were performed. RESULTS Female gender, catheter insertion at the emergency or medical-surgical wards, forearm site, amoxicillin-clavulamate or aminoglycosides were independent predictors of PVP with hazard ratios (95 confidence interval) of 1.46 (1.09-2.15), 1.94 (1.01-3.73), 2.51 (1.29-4.88), 1.93 (1.20-3.01), 2.15 (1.45-3.20) and 2.10 (1.01-4.63), respectively. Maximum phlebitis incidence was reached sooner in patients with ≥2 risk factors (days 3-4) than in those with <2 (days 4-5). Conditional failure increased from 0.08 phlebitis/one catheter-day for devices with ≤1 risk factors to 0.26 for those with ≥3. The greatest benefit of routine catheter exchange was obtained by replacement every 60h. However, this benefit differed according to the number of risk factors: 24.8% reduction with ≥3, 13.1% with 2, and 9.2% with ≤1. CONCLUSIONS PVP dynamics is highly influenced by identifiable risk factors which may be used to refine the strategy of catheter management. Routine replacement every 72h seems to be strictly necessary only in high-risk catheters.