Increasing the rigor of surveillance may lower the rate of ventilator-associated pneumonia independent of patient care, which may cause hospitals to focus less on their VAP prevention efforts, according to a commentary in the American Journal of Infection Control.
The author, Michael Klompas, MD, MPH, an assistant professor in the department of population medicine at Harvard Medical School and Harvard Pilgrim Health Care Institute in Boston, argues that lowered VAP rates from stricter surveillance methods may mislead hospitals about the effectiveness of their interventions. Here are eight initiatives "that well-intentioned hospitals might be considering to make VAP surveillance more rigorous. Each of these initiatives will lower apparent VAP rates despite not materially improving patient care," he wrote.
1. Interpret clinical signs as strictly as possible. VAP surveillance includes assessing worsening oxygenation, change in the character of sputum and increased suctioning requirements. Judgment of these criteria can be variable, however, due to patients' complex and dynamic clinical findings, according to Dr. Klompas. "Stricter observers seeking unambiguous, sustained evidence that surveillance criteria are being met will inevitably assign fewer VAPs," he wrote.
2. Interpret chest radiographs as strictly as possible. Similarly to the interpretation of clinical signs, the interpretation of chest radiographs can be subjective due to the quality of the films. Interpreters may thus conclude an opacity in the film is due to something other than pneumonia or the technical limitations of the radiograph. "Seeking unambiguous radiologic evidence for new or progressive infiltrates invariably leads to rejection of patients with otherwise compatible clinical syndromes for VAP," Dr. Klompas wrote.
3. Require consensus between two or more infection preventionists. VAP surveyors often differ on their assignment of VAP, according to Dr. Klompas. Requiring consensus among surveyors can reduce the number of reported VAPs because a surveyor may disagree with some of the VAP designations and a consensus would not be reached.
4. Seek endorsement of intensivists before "certifying" suspected cases as VAP. As in requiring consensus among preventionists, requiring agreement from an intensivist may also be difficult due to individuals' different interpretations. "The more observers permitted a veto, the lower the number of VAPs," Dr. Klompas wrote.
5. Require bronchoalveolar lavage for diagnosis. While bronchoalveolar lavage cultures produce a quantitative indication of infection, only a minority of patients who meet a clinical definition of VAP test positive for this test, according to Dr. Klompas. Although this test seems to eliminate the subjectivity in assigning VAPs, it still skews the reported number of VAP cases due to its limited validity.
6. Set quantitative growth thresholds for endotracheal aspirate and BAL cultures. As in the previous intervention, setting a quantitative growth threshold to diagnose VAP yields positive results for only a fraction of patients who otherwise meet the diagnostic criteria. In one study, using BAL reduced the number of reported VAP cases but did not change patient outcomes or the rate of clinically suspected VAP, according to Dr. Klompas.
7. Transfer patients who require prolonged mechanical ventilation. Patients on prolonged ventilation are at high risk for developing VAP. Transferring these high-risk patients to other facilities decreases the hospital's rate of VAP without making real changes in patient care.
8. Expand surveillance to include uncomplicated postoperative patients. Postoperative patients who need a few hours to wean from mechanical ventilation and are admitted to the intensive care unit increase the unit's ventilator day count. Adding low-risk patients to ventilator days lowers the overall VAP rate.
Dr. Klompas cautions hospitals on making VAP surveillance more rigorous, as the resulting decline in reported VAP rates may mislead hospitals about the effectiveness of their VAP prevention programs. He suggests focusing on objective measures of adherence to VAP prevention programs and revising the surveillance definition.
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The author, Michael Klompas, MD, MPH, an assistant professor in the department of population medicine at Harvard Medical School and Harvard Pilgrim Health Care Institute in Boston, argues that lowered VAP rates from stricter surveillance methods may mislead hospitals about the effectiveness of their interventions. Here are eight initiatives "that well-intentioned hospitals might be considering to make VAP surveillance more rigorous. Each of these initiatives will lower apparent VAP rates despite not materially improving patient care," he wrote.
1. Interpret clinical signs as strictly as possible. VAP surveillance includes assessing worsening oxygenation, change in the character of sputum and increased suctioning requirements. Judgment of these criteria can be variable, however, due to patients' complex and dynamic clinical findings, according to Dr. Klompas. "Stricter observers seeking unambiguous, sustained evidence that surveillance criteria are being met will inevitably assign fewer VAPs," he wrote.
2. Interpret chest radiographs as strictly as possible. Similarly to the interpretation of clinical signs, the interpretation of chest radiographs can be subjective due to the quality of the films. Interpreters may thus conclude an opacity in the film is due to something other than pneumonia or the technical limitations of the radiograph. "Seeking unambiguous radiologic evidence for new or progressive infiltrates invariably leads to rejection of patients with otherwise compatible clinical syndromes for VAP," Dr. Klompas wrote.
3. Require consensus between two or more infection preventionists. VAP surveyors often differ on their assignment of VAP, according to Dr. Klompas. Requiring consensus among surveyors can reduce the number of reported VAPs because a surveyor may disagree with some of the VAP designations and a consensus would not be reached.
4. Seek endorsement of intensivists before "certifying" suspected cases as VAP. As in requiring consensus among preventionists, requiring agreement from an intensivist may also be difficult due to individuals' different interpretations. "The more observers permitted a veto, the lower the number of VAPs," Dr. Klompas wrote.
5. Require bronchoalveolar lavage for diagnosis. While bronchoalveolar lavage cultures produce a quantitative indication of infection, only a minority of patients who meet a clinical definition of VAP test positive for this test, according to Dr. Klompas. Although this test seems to eliminate the subjectivity in assigning VAPs, it still skews the reported number of VAP cases due to its limited validity.
6. Set quantitative growth thresholds for endotracheal aspirate and BAL cultures. As in the previous intervention, setting a quantitative growth threshold to diagnose VAP yields positive results for only a fraction of patients who otherwise meet the diagnostic criteria. In one study, using BAL reduced the number of reported VAP cases but did not change patient outcomes or the rate of clinically suspected VAP, according to Dr. Klompas.
7. Transfer patients who require prolonged mechanical ventilation. Patients on prolonged ventilation are at high risk for developing VAP. Transferring these high-risk patients to other facilities decreases the hospital's rate of VAP without making real changes in patient care.
8. Expand surveillance to include uncomplicated postoperative patients. Postoperative patients who need a few hours to wean from mechanical ventilation and are admitted to the intensive care unit increase the unit's ventilator day count. Adding low-risk patients to ventilator days lowers the overall VAP rate.
Dr. Klompas cautions hospitals on making VAP surveillance more rigorous, as the resulting decline in reported VAP rates may mislead hospitals about the effectiveness of their VAP prevention programs. He suggests focusing on objective measures of adherence to VAP prevention programs and revising the surveillance definition.
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