Assessment of Symptom, Disability, and Financial Trajectories in Patients Hospitalized for COVID-19 at 6 Months.

Importance: Individuals who survived COVID-19 often report persistent symptoms, disabilities, and financial consequences. However, national longitudinal estimates of symptom burden remain limited. Objective: To measure the incidence and changes over time in symptoms, disability, and financial status after COVID-19-related hospitalization. Design, Setting, and Participants: A national US multicenter prospective cohort study with 1-, 3-, and 6-month postdischarge visits was conducted at 44 sites participating in the National Heart, Lung, and Blood Institute Prevention and Early Treatment of Acute Lung Injury Network's Biology and Longitudinal Epidemiology: COVID-19 Observational (BLUE CORAL) study. Participants included hospitalized English- or Spanish-speaking adults without severe prehospitalization disabilities or cognitive impairment. Participants were enrolled between August 24, 2020, and July 20, 2021, with follow-up occurring through March 30, 2022. Exposure: Hospitalization for COVID-19 as identified with a positive SARS-CoV-2 molecular test. Main Outcomes and Measures: New or worsened cardiopulmonary symptoms, financial problems, functional impairments, perceived return to baseline health, and quality of life. Logistic regression was used to identify factors associated with new cardiopulmonary symptoms or financial problems at 6 months. Results: A total of 825 adults (444 [54.0%] were male, and 379 [46.0%] were female) met eligibility criteria and completed at least 1 follow-up survey. Median age was 56 (IQR, 43-66) years; 253 (30.7%) participants were Hispanic, 145 (17.6%) were non-Hispanic Black, and 360 (43.6%) were non-Hispanic White. Symptoms, disabilities, and financial problems remained highly prevalent among hospitalization survivors at month 6. Rates increased between months 1 and 6 for cardiopulmonary symptoms (from 67.3% to 75.4%; P = .001) and fatigue (from 40.7% to 50.8%; P < .001). Decreases were noted over the same interval for prevalent financial problems (from 66.1% to 56.4%; P < .001) and functional limitations (from 55.3% to 47.3%; P = .004). Participants not reporting problems at month 1 often reported new symptoms (60.0%), financial problems (23.7%), disabilities (23.8%), or fatigue (41.4%) at month 6. Conclusions and Relevance: The findings of this cohort study of people discharged after COVID-19 hospitalization suggest that recovery in symptoms, functional status, and fatigue was limited at 6 months, and some participants reported new problems 6 months after hospital discharge.

Prevalence, Characteristics, and Outcomes of Emergency Department Discharge Among Patients With Sepsis.

Importance: Sepsis guidelines and research have focused on patients with sepsis who are admitted to the hospital, but the scope and implications of sepsis that is managed in an outpatient setting are largely unknown. Objective: To identify the prevalence, risk factors, practice variation, and outcomes for discharge to outpatient management of sepsis among patients presenting to the emergency department (ED). Design, Setting, and Participants: This cohort study was conducted at the EDs of 4 Utah hospitals, and data extraction and analysis were performed from 2017 to 2021. Participants were adult ED patients who presented to a participating ED from July 1, 2013, to December 31, 2016, and met sepsis criteria before departing the ED alive and not receiving hospice care. Exposures: Patient demographic and clinical characteristics, health system parameters, and ED attending physician. Main Outcomes and Measures: Information on ED disposition was obtained from electronic medical records, and 30-day mortality data were acquired from Utah state death records and the US Social Security Death Index. Factors associated with ED discharge rather than hospital admission were identified using penalized logistic regression. Variation in ED discharge rates between physicians was estimated after adjustment for potential confounders using generalized linear mixed models. Inverse probability of treatment weighting was used in the primary analysis to assess the noninferiority of outpatient management for 30-day mortality (noninferiority margin of 1.5%) while adjusting for multiple potential confounders. Results: Among 12 333 ED patients with sepsis (median [IQR] age, 62 [47-76] years; 7017 women [56.9%]) who were analyzed in the study, 1985 (16.1%) were discharged from the ED. After penalized regression, factors associated with ED discharge included age (adjusted odds ratio [aOR], 0.90 per 10-y increase; 95% CI, 0.87-0.93), arrival to ED by ambulance (aOR, 0.61; 95% CI, 0.52-0.71), organ failure severity (aOR, 0.58 per 1-point increase in the Sequential Organ Failure Assessment score; 95% CI, 0.54-0.60), and urinary tract (aOR, 4.56 [95% CI, 3.91-5.31] vs pneumonia), intra-abdominal (aOR, 0.51 [95% CI, 0.39-0.65] vs pneumonia), skin (aOR, 1.40 [95% CI, 1.14-1.72] vs pneumonia) or other source of infection (aOR, 1.67 [95% CI, 1.40-1.97] vs pneumonia). Among 89 ED attending physicians, adjusted ED discharge probability varied significantly (likelihood ratio test, P < .001), ranging from 8% to 40% for an average patient. The unadjusted 30-day mortality was lower in discharged patients than admitted patients (0.9% vs 8.3%; P < .001), and their adjusted 30-day mortality was noninferior (propensity-adjusted odds ratio, 0.21 [95% CI, 0.09-0.48]; adjusted risk difference, 5.8% [95% CI, 5.1%-6.5%]; P < .001). Alternative confounder adjustment strategies yielded odds ratios that ranged from 0.21 to 0.42. Conclusions and Relevance: In this cohort study, discharge to outpatient treatment of patients who met sepsis criteria in the ED was more common than previously recognized and varied substantially between ED physicians, but it was not associated with higher mortality compared with hospital admission. Systematic, evidence-based strategies to optimize the triage of ED patients with sepsis are needed.

Evaluating the Balance Between Privacy and Access in Digital Information Sharing.

OBJECTIVES: Access to personal health records in an ICU by persons involved in the patient's care (referred to broadly as "family members" below) has the potential to increase engagement and reduce the negative psychologic sequelae of such hospitalizations. Currently, little is known about patient preferences for information sharing with a designated family member in the ICU. We sought to understand the information-sharing preferences of former ICU patients and their family members and to identify predictors of information-sharing preferences. DESIGN: We performed an internet survey that was developed by a broad, multidisciplinary team of stakeholders. Formal pilot testing of the survey was conducted prior to internet survey administration to study subjects. SETTING: Internet survey. SUBJECTS: Subjects included English-speaking adults who had an ICU experience or a family member with ICU experience between 2013 and 2016. We used panel sampling to ensure an ethnically representative sample of the U.S. population. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: One thousand five hundred twenty surveys were submitted, and 1,470 were included in analysis. The majority of respondents (93.6%) stated that they would want to share present and past medical history, either all or that related to their ICU stay, with a designated family member of their choosing. The majority (79%) would also want their designated family member to be able to access that information from a home computer. Although most respondents preferred to share all types of information, they indicated varying levels of willingness to share specific types of more sensitive information. Information-sharing preferences did not differ by age, sex, ethnicity, or type of prior experience in the ICU (i.e., patient or family member). CONCLUSIONS: In the context of an ICU admission, sharing personal health information with a person of the patient's choosing appears desirable for most patients and family members. Policies and implementation of regulations should take this into consideration.

Depression and Change in Caregiver Burden Among Family Members of Intensive Care Unit Survivors.

BACKGROUND: Family members of patients in intensive care units may experience psychological distress and substantial caregiver burden. OBJECTIVE: To evaluate whether change in caregiver burden from intensive care unit admission to 3-month follow-up is associated with caregiver depression at 3 months. METHODS: Caregiver burden was assessed at enrollment and 3 months later, and caregiver depression was assessed at 3 months. Depression was measured with the Hospital Anxiety and Depression Score. The primary analysis was the association between depression at 3 months and change in caregiver burden, controlling for a history of caregiver depression. RESULTS: One hundred one participants were enrolled; 65 participants had a surviving loved one and completed 3-month follow-up. At 3-month follow-up, 12% of participants met criteria for depression. Increased caregiver burden over time was significantly associated with depression at follow-up (Fisher exact test, P = .004), although this association was not significant after controlling for self-reported history of depression at baseline (Cochran-Mantel-Haenszel test, P = .23). CONCLUSIONS: Family members are increasingly recognized as a vulnerable population susceptible to negative psychological outcomes after a loved one's admission to the intensive care unit. In this small sample, no significant association was found between change in caregiver burden and depression at 3 months after controlling for baseline depression.

Alive and Ventilator Free: A Hierarchical, Composite Outcome for Clinical Trials in the Acute Respiratory Distress Syndrome.

OBJECTIVES: Survival from acute respiratory distress syndrome is improving, and outcomes beyond mortality may be important for testing new treatments. The "ventilator-free days" score, is an established composite that equates ventilation on day 28 to death. A hierarchical outcome treating death as a worse than prolonged ventilation would enhance face validity, but performance characteristics and reporting of such an outcome are unknown. We therefore evaluated the performance of a novel hierarchical composite endpoint, the Alive and Ventilator Free score. DESIGN: Using data from four Acute Respiratory Distress Syndrome Network clinical trials, we compared Alive and Ventilator Free to the ventilator-free days score. Alive and Ventilator Free compares each patient with every other patient in a win-lose-tie for each comparison. Duration of mechanical ventilation is only compared if both patients survived. We evaluated power of Alive and Ventilator Free versus ventilator-free days score under various circumstances. SETTING: ICUs within the Acute Respiratory Distress Syndrome Network. PATIENTS: Individuals enrolled in four Acute Respiratory Distress Syndrome Network trials. INTERVENTIONS: None for this analysis. MEASUREMENTS AND MAIN RESULTS: Within the four trials (n = 2,410 patients), Alive and Ventilator Free and ventilator-free days score had similar power, with Alive and Ventilator Free slightly more powerful when a mortality difference was present, and ventilator-free days score slightly more powerful with a difference in duration of mechanical ventilation. Alive and Ventilator Free less often found in favor of treatments that increased mortality and increased days free of ventilation among survivors. CONCLUSIONS: A hierarchical composite endpoint, Alive and Ventilator Free, preserves statistical power while improving face validity. Alive and Ventilator Free is less prone to favor a treatment with discordant effects on survival and days free of ventilation. This general approach can support complex outcome hierarchies with multiple constituent outcomes. Approaches to interpretation of differences in Alive and Ventilator Free are also presented.

Impact of Critical Illness on Resource Utilization: A Comparison of Use in the Year Before and After ICU Admission.

OBJECTIVES: Increasingly, patients admitted to an ICU survive to hospital discharge; many with ongoing medical needs. The full impact of an ICU admission on an individual's resource utilization and survivorship trajectory in the United States is not clear. We sought to compare healthcare utilization among ICU survivors in each year surrounding an ICU admission. DESIGN: Retrospective cohort of patients admitted to an ICU during one calendar year (2012) in a multipayer healthcare system. We assessed mortality, hospital readmissions (categorized by ambulatory care sensitive conditions and emergency department), and outpatient visits. We compared the proportion of patients with visits during the pre-ICU year versus the post-ICU year. PATIENTS: People admitted to an Intermountain healthcare ICU for greater than 48 hours in the year 2012 INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS: Among 4,074 ICU survivors, 45% had increased resource utilization. Readmission rates at 30-day, 90-day, and 1-year were 15%, 26%, and 43%. The proportion of patients with a hospital admission increased significantly in the post-ICU period (43% vs 29%; p < 0.001). Of patients with a readmission in the post-ICU period, 24% were ambulatory care sensitive condition. Patients with increased utilization differed by socioeconomic status, insurance type, and severity of illness. Sixteen percent of patients had either an emergency department or inpatient admission, but no outpatient visits during the post-ICU period. CONCLUSIONS: An ICU admission is associated with increased resource utilization including hospital readmissions, with many due to an ambulatory care sensitive condition. Lower socioeconomic status and higher severity of illness are associated with increased resource utilization. After an ICU visit patients seem to use hospital resources over outpatient resources. Interventions to improve and coordinate care after ICU discharge are needed.

Prospective Assessment of the Feasibility of a Trial of Low-Tidal Volume Ventilation for Patients with Acute Respiratory Failure.

RATIONALE: Low-tidal volume ventilation (LTVV; 6 ml/kg) benefits patients with acute respiratory distress syndrome and may aid those with other causes of respiratory failure. Current early ventilation practices are poorly defined. OBJECTIVES: We observed patients with acute respiratory failure to assess the feasibility of a pragmatic trial of LTVV and to guide experimental design. METHODS: We prospectively enrolled consecutive patients with acute respiratory failure admitted to intensive care units expected to participate in the proposed trial. We collected clinical data as well as information on initial and daily ventilator settings and inpatient mortality. We estimated the benefit of LTVV using predictive linear and nonlinear models. We simulated models to estimate power and feasibility of a cluster-randomized trial of LTVV versus usual care in acute respiratory failure. RESULTS: We included 2,484 newly mechanically ventilated patients (31% with acute respiratory distress syndrome) from 49 hospitals. Hospital mortality was 28%. Mean initial tidal volume was 7.1 ml/kg predicted body weight (95% confidence interval, 7.1-7.2), with 78% of patients receiving tidal volumes less than or equal to 8 ml/kg. Our models estimated a mortality benefit of 0-2% from LTVV compared with usual care. Simulation of a stepped-wedged cluster-randomized trial suggested that enrollment of 106,361 patients would be necessary to achieve greater than 90% power. CONCLUSIONS: Use of initial tidal volumes less than 8 ml/kg predicted body weight was common at hospitals participating in the National Heart, Lung, and Blood Institute Prevention and Early Treatment of Acute Lung Injury (PETAL) Network. After considering the size and budgetary requirement for a cluster-randomized trial of LTVV versus usual care in acute respiratory failure, the PETAL Network deemed the proposed trial infeasible. A rapid observational study and simulations to model anticipated power may help better design trials.

A Road Map for Advancing the Practice of Respect in Health Care: The Results of an Interdisciplinary Modified Delphi Consensus Study.

BACKGROUND: Most health care organizations' efforts to reduce harm focus on physical harm, but other forms of harm are both prevalent and important. These "nonphysical" harms can be framed using the concepts of respect and dignity: Disrespect is an affront to dignity and can cause harm. Organizations should strive to eliminate disrespect to patients, to families, and among health care professionals. METHODS: A diverse, interdisciplinary panel of experts was convened to discuss strategies to guide health care systems to embrace an expanded definition of patient harm that includes nonphysical harm. Subsequently, using a modified Delphi process, a guide was developed for health care professionals and organizations to improve the practice of respect across the continuum of care. RESULTS: Five rounds of surveys were required to reach predefined metrics of consensus. Delphi participants identified a total of 25 strategies associated with six high-level recommendations: "Leaders must champion a culture of respect and dignity"; with other professionals sharing the responsibility to "Promote accountability"; "Engage and support the health care workforce"; "Partner with patients and families"; "Establish systems to learn about and improve the practice of respect"; and "Expand the research agenda and measurement tools, and disseminate what is learned." CONCLUSION: Harm from disrespect is the next frontier in preventable harm. This consensus statement provides a road map for health care organizations and professionals interested in engaging in a reliable practice of respect. Further work is needed to develop the specific tactics that will lead health care organizations to prevent harm from disrespect.

Association of hospice utilization and publicly reported outcomes following hospitalization for pneumonia or heart failure: a retrospective cohort study.

BACKGROUND: The Center for Medicare and Medicaid Services (CMS) and the Hospital Quality Alliance began collecting and reporting United States hospital performance in the treatment of pneumonia and heart failure in 2008. Whether the utilization of hospice might affect CMS-reported mortality and readmission rates is not known. METHODS: Hospice utilization (mean days on hospice per decedent) for 2012 from the Dartmouth Atlas (a project of the Dartmouth Institute that reports a variety of public health and policy-related statistics) was merged with hospital-level 30-day mortality and readmission rates for pneumonia and heart failure from CMS. The association between hospice use and outcomes was analyzed with multivariate quantile regression controlling for quality of care metrics, acute care bed availability, regional variability and other measures. RESULTS: 2196 hospitals reported data to both CMS and the Dartmouth Atlas in 2012. Higher rates of hospice utilization were associated with lower rates of 30-day mortality and readmission for pneumonia but not for heart failure. Higher quality of care was associated with lower rates of mortality for both pneumonia and heart failure. Greater acute care bed availability was associated with increased readmission rates for both conditions (p < 0.05 for all). CONCLUSIONS: Higher rates of hospice utilization were associated with lower rates of 30-day mortality and readmission for pneumonia as reported by CMS. While causality is not established, it is possible that hospice referrals might directly affect CMS outcome metrics. Further clarification of the relationship between hospice referral patterns and publicly reported CMS outcomes appears warranted.

A Clinician's Guide to Privacy and Communication in the ICU.

OBJECTIVE: To review the legal issues concerning family members' access to information when patients are in the ICU. DATA SOURCES: U.S. Code, U.S. Code of Federal Regulations, and state legislative codes. DATA EXTRACTION: Relevant legal statutes and regulations were identified and reviewed by the two attorney authors (L. F., M. A. V.). STUDY SELECTION: Not applicable. DATA SYNTHESIS: Review by all coauthors. CONCLUSIONS: The Health Insurance Portability and Accountability Act and related laws should not be viewed as barriers to clinicians sharing information with ICU patients and their loved ones. Generally, under Health Insurance Portability and Accountability Act, personal representatives have the same authority to receive information that patients would otherwise have. Persons involved in the patient's care also may be given information relevant to the episode of care unless the patient objects. ICUs should develop policies for handling the issues we identify about such information sharing, including policies for responding to telephone inquiries and methods for giving patients the opportunity to object to sharing information with individuals involved in their care. ICU clinicians also should be knowledgeable of their state's laws about how to identify patients' personal representatives and the authority of those representatives. Finally, ICU clinicians should be aware of any special restrictions their state places on medical information. In aggregate, these strategies should help ICU managers and clinicians facilitate robust communication with patients and their loved ones.

Glasgow Coma Scale score dominates the association between admission Sequential Organ Failure Assessment score and 30-day mortality in a mixed intensive care unit population.

OBJECTIVE: The Sequential Organ Failure Assessment (SOFA) score, a measure of multiple-organ dysfunction syndrome, is used to predict mortality in critically ill patients by assigning equally weighted scores across 6 different organ systems. We hypothesized that specific organ systems would have a greater association with mortality than others. DESIGN: We retrospectively studied patients admitted over a period of 4.2 years to a mixed-profile intensive care unit (ICU). We recorded age and comorbidities, and calculated SOFA organ scores. The primary outcome was 30-day all-cause mortality. We determined which organ subscores of the SOFA score were most associated with mortality using multiple analytic methods: random forests, conditional inference trees, distanced-based clustering techniques, and logistic regression. SETTING: A 24-bed mixed-profile adult ICU that cares for medical, surgical, and trauma (level 1) patients at an academic referral center. PATIENTS: All patients' first admission to the study ICU during the study period. MEASUREMENTS AND MAIN RESULTS: We identified 9120 first admissions during the study period. Overall 30-day mortality was 12%. Multiple analytical methods all demonstrated that the best initial prediction variables were age and the central nervous system SOFA subscore, which is determined solely by Glasgow Coma Scale score. CONCLUSIONS: In a mixed population of critically ill patients, the Glasgow Coma Scale score dominates the association between admission SOFA score and 30-day mortality. Future research into outcomes from multiple-organ dysfunction may benefit from new models for measuring organ dysfunction with special attention to neurologic dysfunction.

Admission decisions and outcomes of community-acquired pneumonia in the homeless population: a review of 172 patients in an urban setting.

OBJECTIVES: We compared admission rates, outcomes, and performance of the CURB-65 mortality prediction score of homeless patients and nonhomeless patients with community-acquired pneumonia (CAP). METHODS: We compared homeless (n = 172) and nonhomeless (n = 1897) patients presenting to a Salt Lake City, Utah, emergency department with CAP from 1996 to 2006. In the homeless cohort, we measured referral from and follow-up with the local homeless health care clinic and arrangement of medical housing. RESULTS: Homeless patients were younger (44 vs 59 years; P < .001) and had lower CURB-65 scores and higher hospitalization risk (severity-adjusted odds ratio = 1.89; 95% confidence interval = 1.33, 2.69) than did nonhomeless patients, with a similar length of stay, median inpatient cost, and median outpatient cost, even after severity adjustment. Of homeless patients, 22% were referred from the homeless health care clinic to the emergency department; 54% of outpatients and 51% of hospital patients were referred back to the clinic, and medical housing was arranged for 23%. CONCLUSIONS: A large cohort of homeless patients with CAP demonstrated higher hospitalization risk than but similar length of stay and costs as nonhomeless patients. The strong relationship between the hospital and homeless health care clinic may have contributed to this finding.

CURB-65 pneumonia severity assessment adapted for electronic decision support.

BACKGROUND: Accurate severity assessment is crucial to the initial management of community-acquired pneumonia (CAP). The CURB-65 (confusion, uremia, respiratory rate, BP, age ≥ 65 years) score contains data that are entered routinely in electronic medical records and are, thus, electronically calculable. The aim of this study was to determine whether an electronically generated severity estimate using CURB-65 elements as continuous and weighted variables better predicts 30-day mortality than the traditional CURB-65. METHODS: In a retrospective cohort study at a US university-affiliated community teaching hospital, we identified 2,069 patients aged 18 years or older with CAP confirmed by radiographic findings in the ED. CURB-65 elements were extracted from the electronic medical record, and 30-day mortality was identified with the Utah Population Database. Performance of a severity prediction model using continuous and weighted CURB-65 variables was compared with the traditional CURB-65 in the US derivation population and validated in the original 1,048 patients from the CURB-65 international derivation study. RESULTS: The traditional, binary CURB-65 score predicted mortality in the US cohort with an area under the curve (AUC) of 0.82. Our severity prediction model generated from continuous, weighted CURB-65 elements was superior to the traditional CURB-65, with an out-of-bag AUC of 0.86 (P < .001). This finding was validated in the international database, with an AUC of 0.85 for the electronic model compared with 0.80 for the traditional CURB-65 (P = .01). CONCLUSIONS: Using CURB-65 elements as continuous and weighted data improved prediction of 30-day mortality and could be used as a real-time, electronic decision support tool or to adjust outcomes by severity when comparing processes of care.

A modified sequential organ failure assessment score for critical care triage.

OBJECTIVE: The Sequential Organ Failure Assessment (SOFA) score has been recommended for triage during a mass influx of critically ill patients, but it requires laboratory measurement of 4 parameters, which may be impractical with constrained resources. We hypothesized that a modified SOFA (MSOFA) score that requires only 1 laboratory measurement would predict patient outcome as effectively as the SOFA score. METHODS: After a retrospective derivation in a prospective observational study in a 24-bed medical, surgical, and trauma intensive care unit, we determined serial SOFA and MSOFA scores on all patients admitted during the 2008 calendar year and compared the ability to predict mortality and the need for mechanical ventilation. RESULTS: A total of 1770 patients (56% male patients) with a 30-day mortality of 10.5% were included in the study. Day 1 SOFA and MSOFA scores performed equally well at predicting mortality with an area under the receiver operating curve (AUC) of 0.83 (95% confidence interval 0.81-.85) and 0.84 (95% confidence interval 0.82-.85), respectively (P = .33 for comparison). Day 3 SOFA and MSOFA predicted mortality for the 828 patients remaining in the intensive care unit with an AUC of 0.78 and 0.79, respectively. Day 5 scores performed less well at predicting mortality. Day 1 SOFA and MSOFA predicted the need for mechanical ventilation on day 3, with an AUC of 0.83 and 0.82, respectively. Mortality for the highest category of SOFA and MSOFA score (>11 points) was 53% and 58%, respectively. CONCLUSIONS: The MSOFA predicts mortality as well as the SOFA and is easier to implement in resource-constrained settings, but using either score as a triage tool would exclude many patients who would otherwise survive.

Binary cumulative sums and moving averages in nosocomial infection cluster detection.

Clusters of nosocomial infection often occur undetected, at substantial cost to the medical system and individual patients. We evaluated binary cumulative sum (CUSUM) and moving average (MA) control charts for automated detection of nosocomial clusters. We selected two outbreaks with genotyped strains and used resistance as inputs to the control charts. We identified design parameters for the CUSUM and MA (window size, k, alpha, Beta, p(0), p(1)) that detected both outbreaks, then calculated an associated positive predictive value (PPV) and time until detection (TUD) for sensitive charts. For CUSUM, optimal performance (high PPV, low TUD, fully sensitive) was for 0.1 < or = alpha < or = 0.25 and 0.2 < or = Beta < or = 0.25, with p(0) = 0.05, with a mean TUD of 20 (range 8-43) isolates. Mean PPV was 96.5% (relaxed criteria) to 82.6% (strict criteria). MAs had a mean PPV of 88.5% (relaxed criteria) to 46.1% (strict criteria). CUSUM and MA may be useful techniques for automated surveillance of resistant infections.