Usefulness of intrinsic surgical wound infection risk indices as predictors of postoperative pneumonia risk

• Published in: The Journal of hospital infection 1997-04, Vol.35 (4), p.269-276
• Main Authors: Delgado-Rodríguez, M., Medina-Cuadros, M., Martínez-Gallego, G., Sillero-Arenas, M.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Child; Cohort Studies; Cross infection; Cross Infection - etiology; Cross Infection - prevention & control; epidemiology; Female; Humans; Male; Medical sciences; Middle Aged; Miscellaneous; nosocomial pneumonia; Pneumonia - etiology; Pneumonia - prevention & control; Postoperative Complications - prevention & control; Prospective Studies; Risk Factors; Severity of Illness Index; surgery; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgical Wound Infection - complications
• ISSN: 0195-6701; 1532-2939
• DOI: 10.1016/S0195-6701(97)90220-6

The main objective of this report was to use two indices of intrinsic surgical wound infection risk, the SENIC index (Haley et al., 1985) and the NNIS index (Culver et al., 1991), to predict risk of postoperative pneumonia in general surgery patients. A prospective cohort study on 1483 patients admitted under the general surgery speciality of a tertiary hospital was performed. The main outcome measure was postoperative pneumonia. Relative risk and their 95% confidence intervals (CIs) were estimated. Stepwise logistic regression analysis was used to select the main determinant predictors. During follow-up, 19 (1·3%) patients acquired postoperativepneumonia. Common risk factors of postoperative pneumonia were identified: mechanical ventilation, age, upper abdominal surgery, severity of illness, obesity, hypoalbuminaemia, and use of histamine type 2 receptor antagonists. Both the SENIC and the NNIS indices showed a statistically significant association ( P < 0·001) with postoperative pneumonia risk: the higher the score the greater the risk. Stepwise logistic regression analysis selected five variables: (1) mechanical ventilation [odds ratio (OR) = 9·8, 95% CI 2·7–35·6]; (2) upper abdominal surgery (OR = 4·7, 95% CI 1·6–13·9); (3) chronic lung disease (OR = 5·9, 95% CI 1·7–21·2); (4) the NNIS index (OR for each point = 2·2, 95% CI 1·1–4·4); and (5) obesity, measured by a body mass index greater than the 90th percentile (OR = 2·9, 95%, CI 0·9–9·4). In conclusion, both the SENIC and the NNIS indices were related to postoperative pneumonia risk. The NNIS index may be a better predictor.