RESUMEN
OBJECTIVE: To determine the prevalence of difficult venous access in adult patients admitted to a surgical unit. METHOD: This observational prospective cohort study included 235 patients from a Brazilian hospital. Clinical data were collected by direct observation and analyzed by descriptive, inferential statistics, and multiple binomial logistic regressions. Odds ratios were also calculated. RESULTS: Most of the patients (66.4%) were men and self-reported as white (59.2%). The prevalence of difficult intravenous access was 32.8%. Predictors of peripheral intravenous cannula insertion failure were history of difficult intravenous access and nonvisibility of the vein. CONCLUSION: History of difficult intravenous access and a nonvisible venous network were significant predictors of peripheral cannula insertion failure in adults undergoing clinical surgery. The prevalence of difficult intravenous access was 32.8%.