participants rated their perceived

participants rated their perceived pain of BP measurement and IVC. Ninety-five percent confidence intervals (CI) constructed around means and proportions were used to assess group differences. One hundred participants had headache; 100 participants with no headache served as controls. There were no differences between groups with regard to gender, ethnicity, or insurance status. Intravenous catheterization was successful in all 200 participants, with a median intravenous catheter gauge of 20 (range 18-24).