. Author manuscript; available in PMC: 2016 Apr 1.

Published in final edited form as: Crit Care Med. 2015 Apr;43(4):832–839. doi: 10.1097/CCM.0000000000000823

Table 4.

Time to cannulation by access site.

Variable	Short Axis		Long Axis		Absolute Difference^†
Variable	Median Time (sec)	(IQR)	Median Time (sec)	(IQR)	Difference	(95% CI)
Internal Jugular	14.5	(8.0 – 25.5)	9.5	(4.0 – 24.5)	-3	(-9, 3)
Subclavian	66.0	(27.0 – 95.0)	19.0	(11.0 – 57.0)	-27	(-58, -7)

Abbreviations: CI, confidence interval; IQR, interquartile range; sec, seconds.

^†

Wilcoxon signed rank test was used to compare paired median values, and Wilcoxon rank sum test was used to compare independent median values. Nonparametric point estimates and confidence intervals were estimated using the cendif and centile functions of Stata for paired and independent comparisons, respectively. The calculation of median differences using these methods may differ slightly from the value obtained from simple subtraction of group medians.