With this new CBAM rule coupled with ID physician review, approximately one-third of patients recently dismissed from the hospital with a delayed positive culture result had a subsequent modification in antimicrobial therapy. A few examples are listed in . We think that this finding underscores the clinical relevance of delayed post-hospitalization culture results to patient care. Although a positive culture from any sterile site should be addressed, positive blood cultures necessitate more time-expedient and appropriate clinical communication to ensure optimal antimicrobial intervention. Multiple studies illustrate how inadequate early antimicrobial therapy for bloodstream infections leads to poor patient outcomes.7-9
Untreated or suboptimally treated Staphylococcus aureus, Staphylococcus lugdunensis,
species blood-stream infections (more than one-third of delayed blood culture results in the current study) can be a crucial factor toward adverse patient morbidity or mortality.
Clinical Examples of CBAM Identification of Post-hospital Delayed Positive Culture Resultsa
Anaerobic blood cultures typically require prolonged incubation periods, and thus results may not be available during short patient hospitalizations. The presence of anaerobic bacteria in the bloodstream (more than one-third of delayed blood culture results in the current study) may also suggest a more complex and often polymicrobial infection depending on the source and bacteria species.
CBAM is not the only mechanism available to notify primary health care professionals of delayed positive culture results. Many hospital microbiology laboratories, including those at Mayo Clinic, will attempt to contact the hospital physician or service about a positive culture from a sterile body site. This system works relatively well for hospitalized patients but poses challenges for those who have been discharged. One problem with delayed positive culture results is that health care professionals taking care of patients in the hospital are commonly not the same health care professionals who follow up in the outpatient setting. Our laboratory technicians do not have access to patient medical records and do not know whom to contact beyond the inpatient health care professional who originally ordered the culture. Even when the inpatient health care professional is contacted by the microbiology laboratory regarding the delayed positive culture result, that information is commonly not communicated to the appropriate primary outside health care professional or to the patients themselves. Additionally, the laboratory technicians may not be qualified to render opinions to the inpatient physician or service regarding the specific clinical relevance or application of positive culture results.
Many community and academic hospitals utilize physician hospitalists and residents to care for inpatients, and the communication between the inpatient health care professionals and outpatient primary health care professionals is often compromised.10
Resident work hour limitations and frequent patient “sign-offs” to other health care professionals further complicate accurate communication and documentation of pending laboratory results at the time a patient is dismissed from the hospital. During the transition from inpatient to outpatient status, it can be difficult for both the hospital health care professionals following up on pending cultures and the laboratory technicians to determine which person is best suited to address important microbiology test results.
In addition to microbiology, laboratory, and pharmacy data, an important component to the CBAM system is the direct access to inpatient and outpatient Mayo Clinic electronic medical records. The ability to review the actual medical records of patients dismissed from the hospital enables the CBAM-ID physician to both understand the specific clinical application of a patient’s positive culture result and the identity of the patient’s outpatient health care professional. Both the direct and time-efficient notification by CBAM-ID staff to outpatient health care professionals and the opportunities to discuss culture interpretation and management recommendations through expert telephone consultation are why CBAM has a unique and clinically advantageous role at Mayo Clinic. This is not to say that an ID physician is required for this type of medical informatics program to be effective because recognition of delayed positive culture results after hospital dismissal is the primary goal. However, the ID physician can provide additional clinical expertise via a “curbside” or virtual consultation to assist the primary health care professional.
For this rule, CBAM identifies only the post-hospital positive culture results, whereas the CBAM-ID physician is required to interpret the clinical relevancy within the context of each patient’s diagnosis and plan of care. Not all delayed positive culture results or interventions by the CBAM-ID physician require initiation of or change in antimicrobial therapy. Indeed, 421 (79%) of the CBAM-flagged patients reviewed by the CBAM-ID physician did not require intervention or communication with the primary health care professional (); 21 (19%) of the CBAM-ID physician interventions and discussions with primary health care professionals did not involve any change in patient management. These results often reflected an attentive primary health care professional who was aware of the positive culture result and had already implemented an appropriate management plan. Patient-specific information outlined by the primary health care professional, including palliative care, chronic suppression, or specific patient wishes, commonly led to alternative and appropriate antimicrobial treatment plans. In addition, delayed growth of bacteria from some tissue sites may have been expected (eg, repeatedly positive bacterial growth from surgically débrided tissues or fastidious bacteria from a known polymicrobial infection) and did not warrant a change in management.
Because of insufficient subsequent outpatient documentation in the patient medical record, 47% of the CBAM-ID physician intervention outcomes could not be accurately determined. This was often due to the large numbers of nonregional (eg, out-of-state and international) patients at our medical center who are managed by non-Mayo Clinic health care professionals. Although the CBAM-ID physician would routinely contact outside health care professionals regarding delayed positive culture results (as documented in a CBAM note), we did not have access to outside, non-Mayo Clinic patient medical records or the identity of many outside health care professionals to confirm whether CBAM-ID physician interventions and recommendations were carried out. Considering the high number of post-hospitalized patients managed outside of the Mayo system, we think that the overall number of patients who had their treatment plan appropriately influenced by CBAM intervention was significantly higher.
Our study has several limitations. As previously mentioned, our inability to access non-Mayo Clinic outpatient records of patients recently dismissed from our hospitals limited a more accurate and comprehensive determination of CBAM intervention impact. We were also not able to contact most outside non-Mayo health care professionals to retrospectively confirm results of CBAM intervention. These are areas for CBAM system improvement that are currently in development. Additionally, some outpatient modifications in antimicrobial therapy (eg, extension of duration of therapy or outpatient therapy) may have been done without documentation in the medical records. We acknowledge that 7 days can be a relatively short incubation for some slow-growing organisms, including mycobacteria and some fungi. After the current study was completed, we extended the time that the CBAM program monitors pending culture results from 7 days to 1 month after hospital dismissal.
We think that our CBAM program provides for both a considerable hospital-based quality improvement initiative and enhanced patient safety. In addition to positive culture results, we are looking to expand this particular CBAM program to identify other important delayed hospital microbiology test results such as polymerase chain reaction on specific microbes, fungal antigens, and select microbial serologies. Whether through CBAM or other informatics programs, it is imperative that safeguards are in place to identify and communicate delayed microbiology information to the appropriate health care professional.