Hospital-acquired respiratory infection in patients admitted in ICU

Background

Hospital-acquired respiratory infection is frequent in ICU patients, especially in those that are submitted to invasive procedures.

Objectives

To study comorbidities and risk factors for the development of hospital-acquired respiratory infection (HARI) and the microbiological profile.

Methods

Retrospective clinical study of 385 patients admitted to our ICU, from January to September 2000. Respiratory infection was defined by 'new' purulent bronchial secretions, with fever (> 38.5°C, axilar) and leucocytosis (>10,000) with or without 'new' pulmonary infiltrate. Patients developing infection after 72 hours of hospitalisation were identified and studied for comorbidities: cancer, imunodepression, HIV positive, diabetes mellitus, pulmonary, cardiac, renal, hepatic and central nervous illnesses, alcohol and drug abuses and cigarette smoking; and risk factors: non-elective oro-tracheal entubation (OTE), re-entubation or traqueostomy, depression of conscience level (8 < ECG < 15), coma (8 ≤ ECG), intoxication, seizures, vomiting, documented tracheal aspiration and respiratory or cardiopulmonary arrest.

Results

During this period 78 (20.3%) patients had the diagnosis of HARI, with a mean age of 55.8 years. 62.8% had comorbidities. This group was compared with an equivalent group of 20 patients, without respiratory infection in the same period (mean age 43 years) – only 40% of these patients had comorbidities. In patients with HARI – 84.6% had at least one risk factor. Non-elective OTE occurred in 73.1% and in 25.6% it was necessary a new invasive procedure of the airway. For those without infection only in 10% it was necessary for new invasion of the airway. The mean time of admission was 15.1 days for those with HARI and 6.85 days for those without. The mortality rate was similar in both (24–25%). A total of 114 organisms were isolated, in 58 patients (74.4%). First intention treatment was proposed according to microbiological profile in only 20% of the patients. In 24% the initial therapeutic option was changed according to the microbial resistences. Only in 9.7% patients it was necessary to change the antibiotic without microbiological guidance.

Conclusions

HARI was diagnosed in 20.3% of the patients admitted to our unit. The infected patients are significantly older than those without infection (P = 0.008) and had more comorbidities (especially chronic restrictive pulmonary illness – P = 0.041). In these patients there were more non-elective OTE and subsequent invasive procedures of the airway. The occurrence of HARI prolonged significantly ICU-hospitalisation (P = 0.024), but did not cause a significant difference in the mortality rate.