Practices associated with reduced infection risk included prophylaxis with second-generation cephalosporins ( HR : 0.70 ; 95 % CI : 0.52 to 0.94 ) , whereas post-operative antibiotic duration > 48 h ( HR : 1.92 ; 95 % CI : 1.28 to 2.88 ) , stress hyperglycemia ( HR : 1.32 ; 95 % CI : 1.01 to 1.73 ) ; intubation time of 24 to 48 h ( HR : 1.49 ; 95 % CI : 1.04 to 2.14 ) ; and ventilation > 48 h ( HR : 2.45 ; 95 % CI : 1.66 to 3.63 ) were associated with increased risk .