Table 3.
Risk factors for ventilator-associated pneumonia: crude and adjusted effect of staffing level
| Risk factor | Early-onset VAP | Late-onset VAP | ||
| Crude HR (95% CI) | Adjusted HR (95% CI) | Crude HR (95% CI) | Adjusted HR (95% CI) | |
| Nurse-to-patient ratio | 0.77 (0.42 to 1.40) | 0.78 (0.42 to 1.45) | 0.43 (0.18 to 1.02) | 0.42 (0.18 to 0.99) |
| Patient age | 1.00 (0.99 to 1.01) | - | 1.00 (0.99 to 1.01) | - |
| Male gender | 0.92 (0.62 to 1.38) | - | 1.15 (0.79 to 1.69) | - |
| Nursing acuity severity score | 0.96 (0.92 to 1.01) | - | 1.03 (1.00 to 1.07) | 1.04 (1.00 to 1.08) |
| Charlson score | 0.89 (0.81 to 0.99) | 0.89 (0.80 to 0.98) | 0.96 (0.87 to 1.05) | |
| Admission diagnosis | ||||
| Infectious disease | 0.75 (0.46 to 1.20) | - | 1.09 (0.75 to 1.60) | - |
| Cardiovascular condition | 1.63 (1.10 to 2.41) | - | 1.47 (0.97 to 2.23) | - |
| Pulmonary disease | 0.77 (0.44 to 1.33) | - | 0.56 (0.31 to 1.02) | 0.53 (0.29 to 0.97) |
| Other | 0.87 (0.53 to 1.41) | - | 0.84 (0.49 to 1.43) | - |
| APACHE II score | ||||
| < 26 | 1 | - | 1 | - |
| 26 to 30 | 1.12 (0.67 to 1.86) | - | 0.92 (0.49 to 1.72) | - |
| > 30 | 0.83 (0.53 to 1.31) | - | 1.08 (0.70 to 1.67) | - |
| Nursing training levela | 0.84 (0.60 to 1.18) | - | 1.19 (0.91 to 1.56) | - |
| Invasive devices | ||||
| Central vascular line | 1.50 (0.92 to 2.45) | 1.71 (1.05 to 2.81) | 3.06 (0.97 to 9.70) | 4.14 (1.26 to 13.55) |
| Peripheral venous line | 2.06 (0.76 to 5.61) | - | 1.47 (0.95 to 2.29) | 1.65 (1.06 to 2.59) |
| Peripheral arterial line | 0.58 (0.32 to 1.06) | - | 5.65 (0.78 to 40.84) | - |
| Urinary catheter | 1.86 (0.66 to 5.26) | - | 1.31 (0.41 to 4.16) | - |
| Nasogastric tube | 1.40 (0.75 to 2.63) | - | 2.39 (0.76 to 7.54) | - |
| Medication | ||||
| Parenteral nutrition | 0.83 (0.49 to 1.41) | - | 0.99 (0.65 to 1.51) | - |
| Therapeutic antibiotic | 0.48 (0.32 to 0.73) | 0.47 (0.31 to 0.71) | 0.51 (0.29 to 0.91) | 0.34 (0.19 to 0.62) |
| Prophylactic antibiotic | 0.58 (0.18 to 1.84) | - | 1.22 (0.56 to 2.63) | - |
| Gastric antacid drug | 1.34 (0.90 to 2.00) | - | 0.98 (0.66 to 1.46) | - |
aNursing training level is the number of intensive care unit certified nurses divided by the number of trainee nurses in critical care. APACHE, Acute Physiology and Chronic Health Evaluation; CI, confidence intervals; HR, hazard ratio; VAP, ventilator-associated pneumonia.