Table 4.

Multivariate regression analyses

		Coef	SE	P-Value	95% CI
Model 1: Individual impact of each element on ICU VAP rates
	Raising of head	−0.66	0.79	0.41	−2.22 to 0.90
	Sedation vacation	−0.88	0.84	0.30	−2.53 to 0.78
	Prevention of stomach ulcers	−0.77	0.86	0.37	−2.45 to 0.91
	DVT prophylaxis	0.50	0.67	0.46	−0.81 to 1.81
Model 2: Impact of complying with one of two VAP-related elements on ICU VAP rates
	One of two VAP-related elements (sedation vacation or raising head of bed)	−0.79	0.55	0.15	−1.86 to 0.29
Model 3: Impact of complying with both VAP-related bundle elements on ICU VAP rates
	Sedation vacation and raising head of bed	−1.81	0.62	<0.01	−3.02 to −0.60
Model 4: Impact of VAP-related bundle elements on ICU CLABSI rates
	Sedation vacation and raising head of bed	−0.22	0.58	0.71	−1.36 to 0.92

All models multivariate OLS regressions with Huber-White standard errors to account for intra-hospital correlations across ICUs. In all models the following covariates were controlled for: geographic region, teaching status, presence of hospital epidemiologist (full and part-time), proportion infection preventionist (IP) certified, IP staffing, use of electronic surveillance system, hand hygiene, years in National Healthcare Safety Network, bedsize and type of ICU.