The study was conducted in the medical-surgical Intensive Care Unit (ICU) of Hospital Israelita Albert Einstein, in São Paulo, SP, Brazil, from June 2010 through December 2011. All 40 ICU beds were included, most of them occupied by private patients; a small percentage of these beds are reserved for patients from the public healthcare network, usually those receiving transplants. The ICU operates with an open staffing model, and the prescription of antimicrobials, as well as other medical decisions, generally reflects the interactions between the specialists involved in each case and the ICU staff physicians, rather than being the sole responsibility of the primary team. However, ultimate decisions are made by the primary physicians responsible for the patient (not the ICU physician that also participates in the care of the patient).
This was a prospective, observational study approved by the IRB of Hospital Israelita Albert Einstein. The requirements for informed consent were waived by our IRB in accordance of the Code of Federal Regulation and of the Privacy Rule. Epidemiologic and laboratory data were captured on a case report form (CRF); the collected information was considered sufficient by the study team to assess the prescription of antimicrobials in the hospital’s ICU.
Patients hospitalized in the ICU and under treatment with antibiotics and/or antifungals were eligible to participate in the study, provided they met the following criteria: CRFs were completed within 72 h of the antimicrobial introduction; age > 18 years; antimicrobial prescription occurred after patient’s admission to the ICU. Patients admitted to any other hospital ward were eligible to participate if the antimicrobial had been prescribed immediately before the patient’s transfer to the ICU. The exclusion criteria were: patients receiving antimicrobial prophylaxis post-operatively and/or due to immunosuppression; >72 h elapsed from the start of antimicrobial therapy; antimicrobials were prescribed outside the ICU, except in those cases described above; and the early postoperative period following organ transplantation.
Data on “recent hospital admission” (within past 3 months) and “prior use of antibiotic therapy” (past 15 days) were obtained from patients, family members, caregivers and/or verified in the patient’s medical records. After the time of admission, all information was obtained exclusively from the patient’s medical records.
Two different procedures for data collection were adopted. For newly admitted patients, if the antimicrobial was prescribed at admission, data were obtained exclusively from the hospital admission forms (physician and nurse), and subsequent lab data were disregarded; if the antimicrobial was introduced after laboratory data were available, the admission forms and the lab report were collected. For patients already hospitalized and who had their antimicrobial regimen newly prescribed and/or changed according to the above mentioned criteria, data were collected from the 24-h period prior to the introduction/change in the regimen; for the purposes of analysis, the most extreme laboratory data were considered.
Organ dysfunctions were diagnosed based on the following measurements: cardiovascular dysfunction: systolic BP <90 mmHg or mean BP <65 mm Hg or use of vasopressors (noradrenaline, dopamine, epinephrine, vasopressin); hematologic disorders: platelets <100,000; liver dysfunction: total bilirubin >2.0 mg/dL; neurological disturbance: drowsiness, confusion, agitation or coma; renal disorders: creatinine >2.0 mg/dL or urine output <0.5 mL/kg/h over the previous 6 h or indication for hemodialysis (except chronic maintenance dialysis); respiratory dysfunction: O2 saturation <90 % with or without O2 supplementation or pO2/FiO2 < 200. Tissue hypoperfusion was quantitatively measured by serum levels of arterial lactate [7, 20].
Previous antibiotic treatment was defined as an antibiotic prescribed for at least 48 h during the fifteen-day period prior to the onset of the current antimicrobial therapy [20].
Patients undergoing long-term steroid therapy, chemotherapy and/or radiation therapy, immunosuppressant therapy due to organ transplantation, and those with neoplasms were considered to be immune compromised.
Patients were considered institutionalized if they had been transferred from nursing homes or equivalent facilities.
Specialists’ opinion
The data were assessed by two infectious diseases specialists with 10- and 17-years experience in the field, both holding master degrees and one of them also a PhD. Both have been members of the hospital’s Nosocomial Infections Control Commission and have a solid reputation in their field; additionally they are routinely involved in the care of critically ill patients admitted to the ICU.
Once completed, all case forms were sent independently to both evaluators (TZSC and ARM) by e-mail. Based on the data received, the evaluator completed a form automatically generated on the e-mail and returned it to the original mailbox for further analysis. On this form, the specialist was required to say if he agreed or disagreed with the prescribed antimicrobial regimen. If he said “no”, he was instructed to justify his disagreement; for example, the regimen was broader than necessary, at least one class of antimicrobial was unnecessary, the regimen was narrower than necessary, or there was no indication for an antimicrobial agent.
Statistical analysis
This is a descriptive study; the only statistical test applied was the chi-square test, at the significance level of p = 0.05. Statistical analyses were done using the Statistical Package for the Social Sciences software (SPSS, Chicago, IL, U.S.A.). For all other tabulations we used Microsoft Excel.
