The impact of the intervention was assessed by estimating the number of infections prevented, lives saved, and excess costs averted. To estimate the number of central line-associated bloodstream infections (CLABSIs) prevented, the number of actual CLABSIs reported are compared with the number of CLABSIs that would have occurred if the pre-intervention ("baseline") rate of CLABSIs per 1,000 line days had persisted (Equation 1). These calculations were done on a monthly basis and totaled between January and August 2012. To estimate the deaths prevented, a range in mortality was assumed (11-31 percent)2. Thus, for each 100 CLABSIs prevented, 11-31 deaths are prevented.
Equation 1. Number of CLABSIs prevented per time period
# CLABSIs Prevented = (Baseline Rate-Observed Rate) x (# Line Days)
Table 9 illustrates the estimated CLABSIs prevented to date. In total, an estimated 131 infections were prevented over the course of the study which translates to an estimated 14-41 deaths prevented. In a 2012 study by Donovan et al.3, $16,800 in excess costs were attributed to NICU-associated bloodstream infection. As such, preventing 131 infections is equivalent to $2,201,776 in excess costs averted. These estimates only consider data currently available and as such do not include infections avoided, deaths prevented, and excess costs averted projected forward.
Table 9. Estimation of infections prevented
CLABSIs | Baseline | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug |
---|---|---|---|---|---|---|---|---|---|
Total CLABSIs (Numerator) |
27 | 15 | 11 | 24 | 18 | 22 | 20 | 18 | 10 |
Total Central Line Days (Denominator) |
13,215 | 15,187 | 15,655 | 17,728 | 18,257 | 19,558 | 17,296 | 16,318 | 11,690 |
CLABSI Rate Per Thousand Line Days | 2.043 | 0.988 | 0.703 | 1.354 | 0.986 | 1.125 | 1.156 | 1.103 | 0.855 |
CLABSIs at Baseline CLABSI Rate (Baseline Rate x days/1000) |
31 | 32 | 36 | 37 | 40 | 35 | 33 | 24 | |
CLABSIs Prevented (CLABSIs at Baseline Rate—CLABSIs at Quarterly Rate)* | 16 | 21 | 12 | 19 | 18 | 15 | 15 | 14 |
*Total CLABSIs prevented may not sum to 131 due to rounding.
2. Powers, RJ & Wirtschafter, DW (2010). Decreasing central line associated bloodstream infection in neonatal intensive care. Clinics in Perinatology 37(1), 247-272.
3. Donovan EF, et al. (2012). The investment case for preventing NICU-associated infections. American Journal of Perinatology [in press].