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Biomedical subjects

Loreen A Herwaldt

Publications and source records attributed to Loreen A Herwaldt.

At least 19 recordsLinked to original sources
PubMed2006

Improving methicillin-resistant Staphylococcus aureus surveillance and reporting in intensive care units.

BACKGROUND: Routine culturing of patients in intensive care units (ICUs) for methicillin-resistant Staphylococcus aureus (MRSA) identifies unrecognized carriers and facilitates timely isolation. However, the benefit of surveillance in detecting prevalent and incident carriers likely varies among ICUs. In addition, many assessments underestimate the incidence of acquisition by including prevalent carriers in the at-risk population. METHODS: We performed a retrospective cohort study using accurate at-risk populations to evaluate the range of benefit of admission and weekly surveillance cultures in detecting otherwise unrecognized MRSA in 12 ICUs in 5 states. RESULTS: We assessed 142 ICU-months. Among the 12 ICUs, the admission prevalence of imported MRSA was 5%-21%, with admission surveillance providing 30%-135% increases in rates of detection. The monthly hospital-associated incidence was 2%-6%, with weekly surveillance providing 7%-157% increases in detection. The common practice of reporting incidence using the total number of patients or total patient-days underestimated incidence by one-third. Surgical ICUs had lower MRSA importation but higher MRSA incidence. Overall, routine surveillance prevented the misclassification of 17% (unit range, 11%-29%) of "incident" carriers, compared with clinical cultures, and increased precaution days by 18% (unit range, 11%-91%). CONCLUSIONS: Routine surveillance significantly increases the detection of MRSA, but this benefit is not uniform across ICUs, even with high compliance and the use of correct denominators.

Academic Medical Centers↗
PubMed2006

Improving the assessment of vancomycin-resistant enterococci by routine screening.

BACKGROUND: As infection with vancomycin-resistant enterococci (VRE) increases in hospitals, knowledge about VRE reservoirs and improved accuracy of epidemiologic measures are needed. Many assessments underestimate incidence by including prevalent carriers in at-risk populations. Routine surveillance cultures can substantially improve prevalence and incidence estimates, and assessing the range of improvement across diverse units is important. METHODS: We performed a retrospective cohort study using accurate at-risk populations to evaluate the range of benefit of admission and weekly surveillance cultures in detecting unrecognized VRE in 14 patient-care units. RESULTS: We assessed 165 unit-months. The admission prevalence of VRE was 2.2%-27.2%, with admission surveillance providing 2.2-17-fold increased detection. Medical units were significantly more likely to admit VRE carriers than were surgical units. Monthly incidence was 0.8%-9.7%, with weekly surveillance providing 3.3-15.4-fold increased detection. The common practice of reporting incidence using the total number of patients, rather than patients at risk, underestimated incidence by one-third. Overall, routine surveillance prevented the misclassification of 43.0% (unit range, 0%-85.7%) of "incident" carriers on the basis of clinical cultures alone and increased VRE precaution days by 2.4-fold (unit range, 2.0-2.6-fold). CONCLUSIONS: Routine surveillance markedly increases the detection of VRE, despite variability across patient-care units. Correct denominators prevent the substantial underestimation of incidence.

Academic Medical Centers↗
PubMed2006

A prospective study of outcomes, healthcare resource utilization, and costs associated with postoperative nosocomial infections.

OBJECTIVE: We evaluated 4 important outcomes associated with postoperative nosocomial infection: costs, mortality, excess length of stay, and utilization of healthcare resources. DESIGN: The outcomes for patients who underwent general, cardiothoracic, and neurosurgical operations were recorded during a previous clinical trial. Multivariable analyses including significant covariates were conducted to determine whether nosocomial infection significantly affected the outcomes. SETTING: A large tertiary care medical center and an affiliated Veterans Affairs Medical Center. PATIENTS: A total of 3,864 surgical patients. RESULTS: The overall nosocomial infection rate was 11.3%. Important covariates included age, Karnofsky score, McCabe and Jackson classification of the severity of underlying disease, National Nosocomial Infection Surveillance system risk index, and number of comorbidities. After accounting for covariates, nosocomial infection was associated with increased postoperative length of stay, increased costs, increased hospital readmission rate, and increased use of antimicrobial agents in the outpatient setting. Nosocomial infection was not associated independently with a significantly increased risk of death in this surgical population. CONCLUSION: Postoperative nosocomial infection was associated with increased costs of care and with increased utilization of medical resources. To accurately assess the effects of nosocomial infections, one must take into account important covariates. Surgeons seeking to decrease the cost of care and resource utilization must identify ways to decrease the rate of postoperative nosocomial infection.

Adult↗
PubMed2006

Descriptive epidemiology and case-control study of patients colonized with vancomycin-resistant enterococcus and methicillin-resistant Staphylococcus aureus.

BACKGROUND: Patients colonized or infected with vancomycin-resistant enterococcus and methicillin-resistant Staphylococcus aureus may be at risk of acquiring vancomycin-resistant S. aureus if the vanA gene is transferred from vancomycin-resistant enterococcus to methicillin-resistant S. aureus. OBJECTIVE: Our goal was to identify risk factors for cocolonization or coinfection (CC/CI) with vancomycin-resistant enterococcus and methicillin-resistant S. aureus. DESIGN: We conducted a descriptive, epidemiologic study of all patients with CC/CI identified from January 1998 to May 2003 and a nested case-control study of a cohort of patients hospitalized in the burn and wound unit. SETTING: We conducted our study in a 813-bed tertiary care university teaching hospital. POPULATION: The study population consisted of patients found to have CC/CI during the study period. METHODS: Descriptive epidemiologic data were collected from hospital records of all patients identified as having CC/CI. A subset of patients hospitalized in the burn and wound unit were included in a case-control study. RESULTS: CC/CI was detected in 71% of the patients during a single hospital stay. The burn and wound unit, which does active surveillance for both organisms, and the general medicine unit, which does not do active surveillance for either organism, cared for more than one-half of these patients. Among patients being cared for in the burn and wound unit, having exposure to 2 or more invasive devices (central venous catheters, indwelling urinary catheters, and enteral feeding tubes) and renal insufficiency were independent risk factors for CC/CI. CONCLUSIONS: Patients with CC/CI are the population at greatest risk for vancomycin-resistant S. aureus colonization or infection. The number of invasive devices to which patients are exposed and, thus, possibly the patients' underlying severity of illness, as well as renal insufficiency, appear to be risk factors for CC/CI.

Adult↗
PubMed2006

A multicenter intervention to prevent catheter-associated bloodstream infections.

BACKGROUND: Education-based interventions can reduce the incidence of catheter-associated bloodstream infection. The generalizability of findings from single-center studies is limited. OBJECTIVE: To assess the effect of a multicenter intervention to prevent catheter-associated bloodstream infections. DESIGN: An observational study with a planned intervention. SETTING: Twelve intensive care units and 1 bone marrow transplantation unit at 6 academic medical centers. PATIENTS: Patients admitted during the study period. INTERVENTION: Updates of written policies, distribution of a 9-page self-study module with accompanying pretest and posttest, didactic lectures, and incorporation into practice of evidence-based guidelines regarding central venous catheter (CVC) insertion and care. MEASUREMENTS: Standard data collection tools and definitions were used to measure the process of care (ie, the proportion of nontunneled catheters inserted into the femoral vein and the condition of the CVC insertion site dressing for both tunneled and nontunneled catheters) and the incidence of catheter-associated bloodstream infection. RESULTS: Between the preintervention period and the postintervention period, the percentage of CVCs inserted into the femoral vein decreased from 12.9% to 9.4% (relative ratio, 0.73; 95% confidence interval [CI], 0.61-0.88); the total proportion of catheter insertion site dressings properly dated increased from 26.6% to 34.4% (relative ratio, 1.29; 95% CI, 1.17-1.42), and the overall rate of catheter-associated bloodstream infections decreased from 11.2 to 8.9 infections per 1,000 catheter-days (relative rate, 0.79; 95% CI, 0.67-0.93). The effect of the intervention varied among individual units. CONCLUSIONS: An education-based intervention that uses evidence-based practices can be successfully implemented in a diverse group of medical and surgical units and reduce catheter-associated bloodstream infection rates.

Academic Medical Centers↗
PubMed2006

Epidemiology of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in a rural state.

BACKGROUND: Most data on methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) isolates come from large tertiary care centers. Infection control personnel need to understand the epidemiology of MRSA and VRE across the continuum of care, including small rural hospitals, to develop effective control strategies. OBJECTIVE: To describe the epidemiology of MRSA and VRE in Iowa. SETTING: Fifteen hospitals in Iowa. Methods Between July 1998 and June 2001, a total of 1,968 S. aureus isolates and 1,845 Enterococcus isolates from patients infected with these pathogens were examined. Multivariate models were developed to evaluate patient and institutional risk factors for MRSA infection and VRE infection. RESULTS: The proportion of S. aureus isolates resistant to methicillin was 31%, and the proportion of Enterococcus isolates resistant to vancomycin was 6%. Independent risk factors for MRSA infection included residence in a long-term care facility, age of more than 60 years, hospitalization in a hospital with less than 200 short-term care beds, and acquiring the infection in the hospital. Independent risk factors for VRE infection included use of a central venous catheter, residence in a long-term care facility, acquisition of infection in the hospital, and hospitalization in a hospital with more than 200 short-term care beds. CONCLUSIONS: In Iowa, the epidemiology of MRSA differ from those of VRE. MRSA has become established in small rural hospitals. Effective MRSA control strategies may require inclusion of all hospitals in a state or region.

Aged↗
PubMed2006

Preventing catheter-associated bloodstream infections: a survey of policies for insertion and care of central venous catheters from hospitals in the prevention epicenter program.

OBJECTIVE: To determine the extent to which evidence-based practices for the prevention of central venous catheter (CVC)-associated bloodstream infections are incorporated into the policies and practices of academic intensive care units (ICUs) in the United States and to determine variations in the policies on CVC insertion, use, and care. DESIGN: A 9-page written survey of practices and policies for nontunneled CVC insertion and care. SETTING: ICUs in 10 academic tertiary-care hospitals. PARTICIPANTS: ICU medical directors and nurse managers. RESULTS: Twenty-five ICUs were surveyed (1-6 ICUs per hospital). In 80% of the units, 5 separate groups of clinicians inserted 24%-50% of all nontunneled CVCs. In 56% of the units, placement of more than two-thirds of nontunneled CVCs was performed in a single location in the hospital. Twenty units (80%) had written policies for CVC insertion. Twenty-eight percent of units had a policy requiring maximal sterile-barrier precautions when CVCs were placed, and 52% of the units had formal educational programs with regard to CVC insertion. Eighty percent of the units had a policy requiring staff to perform hand hygiene before inserting CVCs, but only 36% and 60% of the units required hand hygiene before accessing a CVC and treating the exit site, respectively. CONCLUSION: ICU policy regarding the insertion and care of CVCs varies considerably from hospital to hospital. ICUs may be able to improve patient outcome if evidence-based guidelines for CVC insertion and care are implemented.

Academic Medical Centers↗
PubMed2006

Risk factors for groin wound infection after femoral artery catheterization: a case-control study.

OBJECTIVE: Groin wound infection (GWI) after femoral artery catheterization is unusual. However, several reports of GWI associated with the use of a Perclose device appear in the surgical literature. DESIGN: A case-control study. SETTING: We pooled 23 cases and 83 controls from a university hospital and a community medical center. PATIENTS: A case was defined as a patient who developed a GWI after a femoral artery catheterization. At the university hospital, 3 controls were randomly selected from the at-risk population and matched to each case by time of procedure only (within 2 weeks). At the community medical center, 4 controls were selected and matched to each case by time of procedure (within 2 weeks), sex, and age (within 5 years). RESULTS: We considered several covariates, including age, sex, body mass index, medical conditions, Perclose use, hematoma formation, and antithrombotic therapy. In a multivariate model, only hematoma formation (odds ratio, 68.8; 95% confidence interval, 12.1-391.4) and glycoprotein IIb/IIIa platelet inhibitor therapy (odds ratio, 6.1; 95% confidence interval, 1.1-33.6) were statistically significant predictors of GWI; Perclose use (odds ratio, 0.9; 95% confidence interval, 0.2-3.7) was not a statistically significant predictor of GWI. However, most of the hematomas (15/17) formed after procedures during which a Perclose device was used. CONCLUSION: Perclose use did not have any additional effect on GWI risk beyond the effect that hematoma formation had.

Case-Control Studies↗
PubMed2005

Survey of long-term-care facilities in Iowa for policies and practices regarding residents with methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci.

OBJECTIVES: To identify infection control policies and practices used by long-term-care facilities (LTCFs) in Iowa for residents with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE), and to estimate the prevalence of residents known to have these organisms. DESIGN: Survey. SETTING: LTCFs in Iowa from December 2002 through March 2003. RESULTS: Of the 429 LTCFs in Iowa, 331 (77%) responded to the survey. The estimated prevalence of residents known to have MRSA was 13.4 per 1,000 and that of residents known to have VRE was 2.3 per 1,000. Facilities owned by the government or those with an average of more than 86 occupied beds were more likely to have residents known to have MRSA and VRE (P = .002 and .007, respectively). Of the responding facilities, 7.3% acknowledged that they refused to accept individuals known to have MRSA and 16.9% acknowledged that they refused to accept those known to have VRE. Facilities in large communities (population, > 100,000) were least likely to deny admission to an individual known to have either MRSA or VRE (P = .05). Most facilities reported adhering to the national guidelines, but fewer than half (44.7%) of the respondents had heard of the Iowa Antibiotic Resistance Task Force's guidelines regarding residents with MRSA or VRE. CONCLUSIONS: Many LTCFs in Iowa care for residents known to have MRSA or VRE, but some refuse to admit these individuals. Infection control personnel and public health officials should work together to educate LTCF staff so that residents receive proper care and resistant organisms do not spread within this setting.

Cross Infection↗
PubMed2005

Importance of control group selection for evaluating antimicrobial use as a risk factor for methicillin-resistant Staphylococcus aureus bacteremia.

OBJECTIVE: We investigated the importance of control group selection during an evaluation of antimicrobial use as a risk factor for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia at our institution. METHODS: We performed a case-control study. A case was defined as any patient admitted between January 1997 and May 2001 who developed nosocomial MRSA bacteremia. We used two control groups; control group I consisted of patients with nosocomial methicillin-susceptible S. aureus (MSSA) bacteremia and control group II included only patients without bacteremia. We matched control-patients to case-patients using age, gender, time at risk, and hospital ward. Data collected on all patients included demographics, comorbidities, antibiotic use, time at risk, length of stay, severity of illness, and outcome. RESULTS: We evaluated 63 patients (21 in each group). The three groups were well matched regarding age, gender, underlying diseases, and severity of illness. Patients in the MRSA group were more likely to have received a fluoroquinolone and had a higher mean number of days of fluoroquinolone use than did patients in the MSSA group (P = .027 and P = .015, respectively). However, all measures of fluoroquinolone use were similar for case-patients and for control-patients who did not have nosocomial bloodstream infection. CONCLUSIONS: Control group selection is important in evaluating antimicrobial use as a risk factor for MRSA bacteremia. Using control-patients infected with MSSA, rather than uninfected control-patients, may overestimate the association between antimicrobial use and MRSA infection.

Anti-Bacterial Agents↗
PubMed2005

In their own words: presenting the patient's perspective using research-based theatre.

INTRODUCTION: In this paper we describe the development of a performance piece based on patients' stories of interacting with health care providers, its introduction into the curriculum to dramatise the patient's perspective on health care, and the evaluation of student responses. METHODS: The piece, entitled In Their Own Words, was created from transcripts of interviews with authors who wrote about their experiences of illness. Over the past 4 years, students have performed the piece as a dramatic reading as part of a required course for Year 1 medical students. RESULTS: Analysis of the students' written reflections identified 5 major themes describing what students learned from the performance piece. These themes were: illness evokes emotions and providers must address both the physical and emotional needs of their patients; patients want health care providers to listen well and to understand patients' perspectives; providers' words and gestures profoundly affect patients; patients do not want to be defined, identified or treated as only their symptoms or illnesses, and information and conditions that clinicians consider routine can be very distressing for patients. DISCUSSION: These themes identified in the students' comments represent critical concepts that health care providers must understand so that they can build therapeutic relationships with their patients. Thus, In Their Own Words is an effective tool for increasing students' awareness of patients' experiences of illness, which is a key aspect of learning to provide effective patient-centred care. Presenting patients' stories through dramatic readings represents an innovative approach to incorporating the patient's perspective into medical education.

Communication↗
PubMed2004

Staphylococcus aureus Colonization and Nosocomial Infections: Implications for Prevention.

Colonization with Staphylococcus aureus is a risk factor for invasive S. aureus infections. Intranasal mupirocin has effectively eradicated S. aureus colonization and appears to prevent S. aureus nosocomial infections in some patient populations. In hospitals and communities where mupirocin use has been widespread, resistance to the drug has emerged. New strategies and agents are needed if we want to significantly decrease the risk of S. aureus infections.

Journal Article↗
PubMed2004

Preoperative risk factors for nasal carriage of Staphylococcus aureus.

BACKGROUND: Staphylococcus aureus nasal carriage is a risk factor for surgical-site infections (SSIs) caused by S. aureus, and eradication of carriage reduces postoperative nosocomial infections caused by it. No study has compared large groups of preoperative carriers and non-carriers to identify factors that are linked to S. aureus nasal carriage. METHODS: While conducting a clinical trial evaluating whether mupirocin prevented S. aureus SSIs, we prospectively collected data on 70 patient characteristics that might be associated with S. aureus carriage. We performed stepwise logistic regression analysis. RESULTS: Of the 4,030 patients, 891 (22%) carried S. aureus. Independent risk factors for S. aureus nasal carriage were obesity (odds ratio [OR], 1.29; 95% confidence interval [CI95], 1.11-1.50), male gender (OR, 1.29; CI95, 1.11-1.51), and a history of a cerebrovascular accident (OR, 1.53; CI95, 1.03-2.25) for all patients. Factors associated with nasal carriage varied somewhat by surgical specialty. In all groups, preoperative use of antimicrobial agents was independently associated with a lower risk of carrying S. aureus in the nares. Previously identified risk factors were not significantly associated with S. aureus nasal carriage in this large group of surgical patients. CONCLUSION: Male gender, obesity, and a history of a cerebrovascular accident were identified as risk factors for S. aureus nasal carriage. It remains to be seen whether preoperative weight loss would reduce the rate of nasal carriage. In addition, the value of screening this patient population for S. aureus nasal carriage merits further investigation.

Adult↗
PubMed2004

Accuracy and appropriateness of antimicrobial susceptibility test reporting for bacteria isolated from blood cultures.

Accurate antimicrobial susceptibility testing (AST) and appropriate reporting of AST results for pathogens isolated from blood cultures are critical functions of the microbiology laboratory. We studied AST performance and reporting from positive blood cultures at hospital microbiology laboratories in Iowa. One hundred sixteen episodes of bacteremia from 14 participating hospitals were examined. We detected AST or identification errors for 18 episodes (16%) and judged reporting of AST results to be inappropriate for 38 episodes (33%). Further study is necessary to determine the impact of testing errors and suboptimal reporting of results on the management of bloodstream infection.

Bacteremia↗
PubMed2003

Staphylococcus aureus nasal carriage and surgical-site infections.

The current literature indicates that surgical-site infections significantly increase costs and length of stay. Nosocomial infections that are acquired after operative procedures increase mortality rates. Staphylococcus aureus is a major cause of surgical-site infections among patients, particularly patients who undergo cardiothoracic surgery. Patients who carry S aureus in their nares are at increased risk for surgical-site infections that are caused by this organism. Occasionally, health care workers who carry S aureus in their nares can cause outbreaks of surgical-site infections or other nosocomial infections. Persons who carry S aureus in their nares and have upper respiratory tract infections may spread this organism to numerous staff members and patients. Key measures for decreasing rates of these and other nosocomial infections include the appropriate use of prophylactic antimicrobial agents, surveillance and reporting of infections, and surveillance for clusters of infection caused by the same strain of S aureus and culture and surveys, when appropriate, to help identify infected health care workers. Additionally, surgical masks may prevent health care workers from inadvertent transmission of S aureus from their nares to patients' surgical sites.

Cardiac Surgical Procedures↗
PubMed2003

Hemorrhage after coronary artery bypass graft procedures.

OBJECTIVES: To identify risk factors for excessive bleeding after coronary artery bypass graft (CABG) procedures and to quantify the outcomes related to this complication. DESIGN: We conducted a case-control study to identify risk factors for hemorrhage following CABG surgery and a historical cohort study to quantify outcomes of hemorrhage. SETTING: The cardiothoracic surgery service of a university hospital. RESULTS: Factors associated with excessive blood loss were recent catheterization (odds ratio [OR] = 0.44; 95% confidence interval [CI95], 0.21 to 0.91); age older than 65 years (OR = 1.94; CI95, 0.96 to 3.93); bypass time of 150 minutes or more (OR = 2.91; CI95, 1.09 to 7.81); and postoperative platelet count of 160,000/mm3 or less (OR = 2.36; CI95, 1.06 to 5.22). The attributable cost of a postoperative hemorrhage was $3,866 (P = .0002) overall, $9,912 (P = .0001) for patients who required reoperation, and $3,316 (P = .03) for those treated medically. The median attributable postoperative length of stay was 1 day longer for cases than for controls (P = .011). Postoperatively, patients who hemorrhaged received significantly larger volumes of packed red blood cells (P < .0001), fresh frozen plasma (P < .0001), platelets (P < .0001), plasminate (P = .007), protamine sulfate (P < .0001), desmopressin acetate (P < .0001), and epsilon-aminocaproic acid (P < .0001) than did controls. CONCLUSIONS: Age, duration of bypass, and postoperative platelet count were associated with excessive bleeding. Hemorrhage after CABG surgery significantly increased the length of stay and cost of care.

Age Factors↗