A case-control study on risk factors for early-onset respiratory tract infection in patients admitted in ICU.
BACKGROUND
Respiratory tract infections are common in intensive care units (ICU), with incidences reported from 10 to 65%, and case fatality rates over 20% in pneumonia. This study was designed to identify risk factors for the development of an early onset respiratory tract infection (ERI) and to review the microbiological profile and the effectiveness of first intention antibiotic therapy.


METHODS
Case-control, retrospective clinical study of the patients admitted to the Intensive Care Unit (ICU) of our hospital, a teaching and tertiary care facility, from January to September 2000 who had a respiratory tract infection diagnosed in the first 5 days of hospital stay.


RESULTS
Of the 385 patients admitted to our unit: 129 (33,5%) had a diagnosis of ERI and 86 patients were admitted to the control group. Documented aspiration (adjusted OR = 5,265; 95% CI = 1,155 - 24,007) and fractured ribs (adjusted OR = 12,150; 95% CI = 1,571 - 93,941) were found to be independent risk factors for the development of ERI (multiple logistic regression model performed with the diagnostic group as dependent variable and adjusted for age, sex, SAPS II, documented aspiration, non-elective oro-tracheal intubation (OTI), fractured ribs, pneumothorax and pleural effusion).A total of 78 organisms were isolated in 61 patients (47%). The normal flora of the upper airway (Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenza and Moraxella catharralis) accounted for 72% of all isolations achieved, polimicrobian infections were responsible for 25% of all microbiological documented infections. First intention treatment was, in 62% of the patients, the association amoxacillin+clavulanate, being effective in 75% of the patients to whom it was administered. The patients with ERI needed more days of OTI (6 vs 2, p < 0,001) and mechanical ventilation (6 vs 2, p < 0,001) and had a longer ICU (7 vs 2, p < 0,001) and hospital length of stay (17 vs 11, p = 0,018), when compared with controls.


CONCLUSIONS
In this study documented tracheobronchial aspiration and fractured ribs were identified as independent risk factors for ERI. Microbiological profile was dominated by sensitive micro-organisms. The choice amoxacilin+clavulanate revealed to be a good option with an effectiveness rate of 77% in the patients in whom it was used.
Cardoso
Teresa C
TC
Intensive Care Unit, Hospital Geral de Santo António, Porto, Portugal, Unidade de Cuidados Intensivos Polivalente, Hospital Geral de Santo António, Largo Prof, Abel Salazar, 4099-001 Porto, Portugal. cardoso.tmc@gmail.com
Lopes
Luís M
LM
Carneiro
António H
AH
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease / Q000453:epidemiology*; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D007442:Intubation, Intratracheal / Q000706:statistics & numerical data; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011174:Portugal / Q000453:epidemiology; D012044:Regression Analysis; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012141:Respiratory Tract Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution
D000900:Anti-Bacterial Agents