Logistic regression of surgical infections and environmental factors
| Factor | Superficial SSI | Deep organ/space SSI | ||
|---|---|---|---|---|
| OR (95% CI)* | p value | OR (95% CI)* | p value | |
| ASA class* | ||||
| 2 | 1.86 (1.01–3.42) | 0.041 | ||
| 3 | 1.96 (1.15–3.34) | 0.018 | ||
| 4 | 3.74 (1.45–9.62) | < 0.001 | ||
| 5 | 5.83 (2.03–16.69) | < 0.001 | ||
| Low albumin | 1.93 (1.09–3.41) | 0.023 | ||
| EC bacteria | 1.75 (1.52–2.02) | < 0.001 | ||
| EC fungi | ||||
| 1 | ||||
| 2–5 | 3.41 (1.02–11.39) | 0.04 | ||
| ≥ 6 | 6.23 (2.02–19.13) | < 0.001 | ||
| SC bacteria | 1.96 (1.49–2.16) | < 0.001 | ||
| SC fungi | 1.61 (1.22–2.58) | < 0.001 | ||
| Comorbidity | 1.85 (1.48–2.31) | < 0.001 | ||
| Age | 1.03 (1.01–1.05) | < 0.001 | ||
| Preoperative stay | 1.22 (1.01–1.49) | 0.041 | ||
| Humidity | 1.35 (1.28–1.43) | < 0.001 | ||
| Immunosupression | ||||
| Differential air pressure | 1.31 (1.22–1.42) | < 0.001 | ||
| Prophylaxis† | 0.29 (0.12–0.66) | < 0.001 | 0.29 (0.12–0.66) | < 0.001 |
| Depilation‡ | 0.15 (0.06–0.36) | < 0.001 | 0.15 (0.06–0.36) | < 0.001 |
| Air renewal rate | ||||
| Sex§ | 2.28 (1.19–4.36) | 0.016 | ||
| Nasogastric tube | 1.12 (1.02–1.23) | 0.027 | ||
| Temperature | 1.27 (1.09–1.47) | < 0.001 | ||
| Duration of intervention | 2.05 (1.64–2.57) | < 0.001 | 6.56 (1.5–28.62) | 0.015 |
| Intervention type¶ | ||||
| Clean–contaminated | 3.22 (1.47–7.02) | < 0.001 | ||
| Contaminated | 3.87 (1.58–9.44) | < 0.001 | ||
| Dirty | 1.71 (1.03–2.83) | 0.03 | 5.16 (1.75–15.2) | < 0.001 |
| Transfusion | 3.11 (1.4–6.91) | < 0.001 | ||
ASA = American Society of Anaesthesiologists; CI = confidence interval; EC = environmental contamination; OR = odds ratio; SC = surface contamination; SSI = surgical site infection.
↵* ASA class 1 is the reference group.
↵† Yes is the reference group.
↵‡ Manual razor is the reference group.
↵§ Men are the reference group.
↵¶ Clean is the reference group.