Trauma severity scoring systems as predictors of nosocomial infection

The Risk Factors for Mortality among Septic Trauma Patients: A Retrospective Cohort Study Using the National Trauma Data Bank

Introduction

In trauma patients, the development of sepsis as a hospital complication is significantly associated with morbidity and mortality. We aimed to assess the risk factors associated with in-hospital mortality among trauma patients who developed sepsis during their hospital stay. Material and methods. Using the 2017 National Trauma Data Bank, a retrospective cohort study was conducted to identify adult trauma patients who developed sepsis during their hospital stay. The primary outcome of interest was in-hospital mortality. Multivariate analysis was used to determine the risk factors associated with in-hospital mortality.

Results

1782 trauma patients developed sepsis. 567 patients (31.8%) died during their hospital stay. The following patient factors were associated with higher odds of in-hospital mortality: age (OR = 1.045 95% CI = 1.036-1.054), chronic renal failure (OR = 2.564 95% CI = 1.528-4.301), and liver cirrhosis (OR = 3.699 95% CI = 2.267-6.033). Patients who developed cardiac arrest (OR = 4.994 95% CI = 3.381-7.378), acute kidney injury (OR = 3.808 95% CI = 2.837-5.110), acute respiratory distress syndrome (OR = 1.688 95% CI = 1.197-2.379), and stroke (OR = 1.998 95% CI = 1.075-3.714) during their hospital stay had higher odds of mortality. Higher Glasgow Coma Scale (13-15) at presentation was associated with lower odds of mortality (OR = 0.467 95% CI = 0.328-0.667).

Conclusion

Among trauma patients who developed sepsis, age, chronic renal failure, cirrhosis, the development of cardiac arrest, acute kidney injury, acute respiratory distress syndrome, and stroke in the hospital were associated with in-hospital mortality. These factors can be used to identify patients who are at higher risk of adverse outcomes and implement standardized or protocol-driven methods to improve patient care.

Predictors of Intensive Care Unit Stay in Patients with Acute Traumatic Spinal Cord Injury Above T6

OBJECTIVE

The objective of this study was to identify factors associated with the intensive care unit (ICU) length of stay (LOS) of patients with an acute traumatic spinal cord injury above T6.

METHODS

We performed a retrospective, observational study of patients admitted to an ICU between 1998 and 2017 (n = 241). The LOS was calculated using a cumulative incidence function, with events of death being considered a competing event. Factors associated with the LOS were analyzed using both a cause-specific Cox proportional hazards regression model and a competing risk model. A multistate approach was also used to analyze the impact of nosocomial infections on the LOS.

RESULTS

A total of 211 patients (87.5%) were discharged alive from the ICU (median LOS = 23 days), and 30 (12.4%) died (median LOS = 11 days). In the multivariate analysis after adjusting for variables collected 4 days after the ICU admission, a higher American Spinal Injury Association motor score (subdistribution hazards ratio [sHR] = 1.01), neurological level C5-C8 (HR = 0,64), and lower Sequential Organ Failure Assessment score (sHR = 0.82) and fluid balance (sHR = 0.95) on day 4 were linked to a lower LOS in this unit. In the multivariate analysis, the onset of an infection was significantly associated with a longer LOS when adjusting for variables collected both at ICU admission (adjusted sHR = 0.62; 95% confidence interval = 0.50-0.77) and on day 4 (adjusted hazards ratio = 0.65; 95% confidence interval = 0.52-0.80).

CONCLUSIONS

After adjusting the data for conventional variables, we identified a lower American Spinal Injury Association motor score, injury level C5-C8, a higher Sequential Organ Failure Assessment score on day 4, a more positive fluid balance on day 4, and the onset of an infection as factors independently associated with a longer ICU LOS.

Risk Factors for Infection Following Operative Treatment of Traumatic Upper Extremity Amputation Injury

Background: Identification of the risk factors for surgical site infection (SSI) can be a straightforward and cost-effective measure to reduce or prevent the occurrence of SSI. However, there are no studies that revealed risk factors for SSI for traumatic upper extremity amputation. The aim of this study is to investigate the risk factors that promote SSI after surgery for traumatic upper extremity amputation using a large nationwide database.

Methods: We used data from the Japan Trauma Data Bank. Diagnoses were defined using the Abbreviated Injury Scale code. We applied multivariate logistic regression to evaluate the infection risk factor. We chose age, sex, vital signs, cause and type of trauma, concomitant injury, diabetes, amputation level, Glasgow coma scale, Injury Severity Score (ISS) and blood transfusion within 24 hours following hospital arrival as confounders. Receiver operating characteristic (ROC) curve analysis was adopted to identify thresholds for change in infection risk. We also applied propensity score (PS) matching to adjust for confounding factors that may affect the outcome.

Results: A total of 1,150 patients (967 males, 183 females) had traumatic upper extremity amputation. The mean patient age was 46.5 years. A total of 21 patients (1.8%) suffered from SSI. ISS, blood transfusion, systolic blood pressure (BP) and the upper extremity amputation except for finger were identified as the independent significant risk factors for SSI occurrence by the multivariate analysis (p < 0.05, p < 0.005, p < 0.05 and p < 0.005, respectively). ROC modelling revealed that patients with ISS of over 9 or systolic BP of over 160 had a risk for SSI. After PS matching, the patients with blood transfusion or systolic BP of over 160 had a significantly higher risk of infection (OR 9.0; p = 0.01 and OR 7.0; p = 0.03, respectively).

Conclusions: In treating patients with these risk factors, we must be especially careful in performing thorough debridement and wound care.

Level of Evidence: Level II (Therapeutic)

Multi-Biomarker Prediction Models for Multiple Infection Episodes Following Blunt Trauma

Severe trauma predisposes patients to multiple independent infection episodes (MIIEs), leading to augmented morbidity and mortality. We developed a method to identify increased MIIE risk before clinical signs appear, which is fundamentally different from existing approaches entailing infections' detection after their establishment. Applying machine learning algorithms to genome-wide transcriptome data from 128 adult blunt trauma patients' (42 MIIE cases and 85 non-cases) leukocytes collected ≤48 hr of injury and ≥3 days before any infection, we constructed a 15-transcript and a 26-transcript multi-biomarker panel model with the least absolute shrinkage and selection operator (LASSO) and Elastic Net, respectively, which accurately predicted MIIE (Area Under Receiver Operating Characteristics Curve [AUROC] [95% confidence intervals, CI]: 0.90 [0.84–0.96] and 0.92 [0.86–0.96]) and significantly outperformed clinical models. Gene Ontology and network analyses found various pathways to be relevant. External validation found our model to be generalizable. Our unique precision medicine approach can be applied to a wide range of patient populations and outcomes.

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We describe a method for predicting multiple independent infection episodes (MIIEs).

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We applied machine learning algorithms to transcriptome data to develop models

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The biomarker prediction models significantly outperformed clinical models

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External validation in another trauma cohort found evidence of generalizability

Thefeasibility, appropriateness, and applicability of trauma scoring systems in low and middle-income countries: a systematic review

Background

About 5.8 million people die each year as a result of injuries, and nearly 90% of these deaths occur in low and middle-income countries (LMIC). Trauma scoring is a cornerstone of trauma quality improvement (QI) efforts, and is key to organizing and evaluating trauma services. The objective of this review was to assess the appropriateness, feasibility, and QI applicability of traditional trauma scoring systems in LMIC settings.

Materials and methods

This systematic review searched PubMed, Scopus, CINAHL, and trauma-focused journals for articles describing the use of a standardized trauma scoring system to characterize holistic health status. Studies conducted in high-income countries (HIC) or describing scores for isolated anatomic locations were excluded. Data reporting a score’s capacity to discriminate mortality, feasibility of implementation, or use for QI were extracted and synthesized.

Results

Of the 896 articles screened, 336 were included. Over half of studies (56%) reported Glasgow Coma Scale, followed by Injury Severity Score (ISS; 51%), Abbreviated Injury Scale (AIS; 24%), Revised Trauma Score (RTS; 19%), Trauma and Injury Severity Score (TRISS; 14%), and Kampala Trauma Score (7%). While ISS was overwhelmingly predictive of mortality, 12 articles reported limited feasibility of ISS and/or AIS. RTS consistently underestimated injury severity. Over a third of articles (37%) reporting TRISS assessmentsobserved mortality that was greater than that predicted by TRISS. Several articles cited limited human resources as the key challenge to feasibility.

Conclusions

The findings of this review reveal that implementing systems designed for HICs may not be relevant to the burden and resources available in LMICs. Adaptations or alternative scoring systems may be more effective.

PROSPERO registration number

CRD42017064600.

Denver and Marshall scores successfully predict susceptibility to multiple independent infections in trauma patients

Trauma patients are at risk of repeated hospital-acquired infections, however predictive scores aiming to identify susceptibility to such infections are lacking. The objective of this study was to investigate whether commonly employed disease-severity scores can successfully predict susceptibility to multiple independent infectious episodes (MIIEs) among trauma patients. A secondary analysis of data derived from the prospective, longitudinal study "Inflammation and the Host Response to Injury" ("Glue Grant") was performed. 1,665 trauma patients, older than 16, were included. Patients who died within seven days from the time of injury were excluded. Five commonly used disease-severity scores [Denver, Marshall, Acute Physiology and Chronic Health Evaluation II (APACHE II), Injury Severity Score (ISS), and New Injury Severity Score (NISS)] were examined as independent predictors of susceptibility to MIIEs. The latter was defined as two or more independent infectious episodes during the index hospital stay. Multivariable logistic regression was used for the statistical analysis. 22.58% of the population was found to be susceptible to MIIEs. Denver and Marshall scores were highly predictive of the MIIE status. For every 1-unit increase in the Denver or the Marshall score, there was a respective 15% (Odds Ratio:1.15; 95% CI: 1.07-1.24; p < 0.001) or 16% (Odds Ratio:1.16; 95% CI: 1.09-1.24; p < 0.001) increase in the odds of MIIE occurrence. APACHE II, ISS, and NISS were not independent predictors of susceptibility to MIIEs. In conclusion, the Denver and Marshall scores can reliably predict which trauma patients are prone to MIIEs, prior to any clinical sign of infection. Early identification of these individuals would potentially allow the implementation of rapid, personalized, preventative measures, thus improving patient outcomes and reducing healthcare costs.

Comorbidities in Trauma Injury Severity Scoring System: Refining Current Trauma Scoring System

The revised trauma score combined with the Injury Severity Score (ISS) remains the mostly commonly used system for predicting trauma mortality, but these scoring systems do not account for the patient's comorbidities. This study aims to evaluate the effect of comorbidities on ISS-related mortality and length of stay. A review of our trauma center's data registry from 2014 to 2016 was carried out. Patients were divided according to ISS into two groups: ISS ≤ 15 and ISS > 15. Each ISS group was then subdivided by number of comorbidities into two groups: 1 to 2 or ≥3 comorbidities. Demographic characteristics and outcome measures were compared. ANOVA, chi-squared, and t tests were used with significance defined as P < 0.05. A total 9845 adult trauma patients were admitted to our trauma center during the three-year study period. In the ISS ≤ 15 group, patients with <3 comorbidities had significantly higher mortality rate compared with patients with 1 to 2 comorbidities (1.50% vs 0.12%, P << 0.000007). Comparing the ISS ≤ 15 group with ≥3 comorbidities with the ISS > 15 group with 1 to 2 comorbidities, the mortality rate was significantly higher (23.40% vs 4.50%, P << 0.000002). The ICU length of stay was significantly higher in the ISS ≤ 15 groups (17 vs 10 days, P < 0.05) but similar in the ISS > 15 groups (31 vs 29 days) (P > 0.05). It was concluded that when controlling for injury severity, increased comorbidities are associated with a significantly higher mortality, indicating that they may serve as a marker of lower physiologic reserve and be an independent variable. Adding comorbidity parameters to the current trauma scoring systems can assist in predicting more accurate/reliable outcomes.

Perceptions of Healthcare-Associated Infection and Antibiotic Resistance among Physicians Treating Syrian Patients with War-Related Injuries

Healthcare-associated infections (HAIs) constitute a major contributor to morbidity and mortality worldwide, with a greater burden on low- and middle-income countries. War-related injuries generally lead to large tissue defects, with a high risk of infection. The aim of this study was to explore how physicians in a middle-income country in an emergency setting perceive HAI and antibiotic resistance (ABR). Ten physicians at a Jordanian hospital supported by Médecins Sans Frontières were interviewed face-to-face. The recorded interviews were transcribed verbatim and analyzed by qualitative content analysis with an inductive and deductive approach. The participants acknowledged risk factors of HAI and ABR development, such as patient behavior, high numbers of injured patients, limited space, and non-compliance with hygiene protocols, but did not express a sense of urgency or any course of action. Overuse and misuse of antibiotics were reported as main contributors to ABR development, but participants expressed no direct interrelationship between ABR and HAI. We conclude that due to high patient load and limited resources, physicians do not see HAI as a problem they can prioritize. The knowledge gained by this study could provide insights for the allocation of resources and development of hygiene and wound treatment protocols in resource-limited settings.

The Host Response in Patients with Sepsis Developing Intensive Care Unit-acquired Secondary Infections

RATIONALE

Sepsis can be complicated by secondary infections. We explored the possibility that patients with sepsis developing a secondary infection while in the intensive care unit (ICU) display sustained inflammatory, vascular, and procoagulant responses.

OBJECTIVES

To compare systemic proinflammatory host responses in patients with sepsis who acquire a new infection with those who do not.

METHODS

Consecutive patients with sepsis with a length of ICU stay greater than 48 hours were prospectively analyzed for the development of ICU-acquired infections. Twenty host response biomarkers reflective of key pathways implicated in sepsis pathogenesis were measured during the first 4 days after ICU admission and at the day of an ICU-acquired infection or noninfectious complication.

MEASUREMENTS AND MAIN RESULTS

Of 1,237 admissions for sepsis (1,089 patients), 178 (14.4%) admissions were complicated by ICU-acquired infections (at Day 10 [6-13], median with interquartile range). Patients who developed a secondary infection showed higher disease severity scores and higher mortality up to 1 year than those who did not. Analyses of biomarkers in patients who later went on to develop secondary infections revealed a more dysregulated host response during the first 4 days after admission, as reflected by enhanced inflammation, stronger endothelial cell activation, a more disturbed vascular integrity, and evidence for enhanced coagulation activation. Host response reactions were similar at the time of ICU-acquired infectious or noninfectious complications.

CONCLUSIONS

Patients with sepsis who developed an ICU-acquired infection showed a more dysregulated proinflammatory and vascular host response during the first 4 days of ICU admission than those who did not develop a secondary infection.

Injury Region and Risk of Hospital-Acquired Pneumonia Among Pediatric Trauma Patients

OBJECTIVE

To describe the relationship between injury region and risk of hospital-acquired pneumonia (HAP) in pediatric trauma patients.

METHODS

Analyses included patients <19 years of age from the National Trauma Data Bank, during 2009-2011. Multivariable logistic regression was used to examine the association between injury region and odds of developing HAP stratified by age group.

RESULTS

A total of 71 377 patients were eligible for analysis, and 1818 patients developed pneumonia. In adjusted regression models both younger (11-15 years) and older (16-18 years) adolescents with multisite injuries including the head and neck had higher odds of developing HAP compared with adolescents with isolated head and neck injuries (odds ratio [OR] = 2.04, 95% confidence interval [CI] 1.34-3.10; OR = 1.47, 95% CI 1.14-1.89, respectively), and younger adolescents with multisite injuries not involving the head and neck also had higher odds of developing HAP (OR = 1.97, 95% CI 1.08-3.60). We found no significant association between injury region and risk of HAP in children <11 years of age. Younger and older adolescents with firearm (OR = 1.85, 95% CI 1.00-3.42; OR = 1.39, 95% CI 1.02-1.88, respectively) or pulmonary (OR = 3.78, 95% CI 1.26-11.3; OR = 2.56, 95% CI 1.01-6.51, respectively) injuries had higher odds of developing HAP compared with those with motor vehicle collision injuries.

CONCLUSIONS

Adolescent trauma patients with multisite injuries including the head and neck have a higher risk of developing HAP compared with those with isolated head and neck injuries. We identified several risk factors that can be used to inform future research focused on identifying subgroups at high risk for the development of HAP.

Oral health and ventilator-associated pneumonia among critically ill patients: a prospective study

OBJECTIVE

To evaluate the association between oral health and ventilator-associated pneumonia (VAP) among critically ill patients.

METHODS

A prospective cohort study was conducted among 162 critically ill patients newly intubated and treated with mechanical ventilator in one tertiary hospital in Thailand. Oral health status was assessed using Oral Health Assessment Tool (OHAT), Plaque Index (PI), and number of teeth. VAP, defined as Clinical Pulmonary Infection Score >6, was assessed on Day 4 after intubation. Hazard ratios and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression adjusted for confounders.

RESULTS

Critically ill patients had deteriorating oral health status after intubation. Early-onset VAP developed in 69 patients (42.6%), with VAP incidence of 117 episodes per 1000 ventilator-days. Moderately unhealthy and unhealthy oral conditions based on OHAT scores were associated with a 2.92-fold (95% CI: 1.26-6.74) and 3.22-fold (95% CI: 1.34-7.76) increased risk of VAP. Patients with moderate-to-very poor oral hygiene assessed by PI had increased VAP risk of 1.66-folds (95% CI: 1.001-2.75). The number of teeth was not associated with VAP development.

CONCLUSIONS

There is a strong association between poor oral health and increased risk for early-onset VAP. Routine oral care possibly prevents VAP development among critically ill patients treated with mechanical ventilator.

Nosocomial Infection Surveillance in a Surgical Intensive Care Unit in Spain, 1996-2000: A Time-Trend Analysis

Objective.

To establish the occurrence, distribution, and secular time trend of nosocomial infections (NIs) in a surgical intensive care unit (ICU).

Design and Setting.

Follow-up study in a teaching hospital in Spain.

Methods.

In May 1995 we established an nosocomial infection surveillance system in our surgical ICU. We collected information daily for all patients who were in the ICU for at least 48 hours (546 patients from 1996 through 2000). We used the Centers for Disease Control and Prevention definitions and criteria for infections. Monthly, we determined the site-specific incidence densities of NIs, the rates of medical device use, and the Poisson probability distribution, which determined whether the case count equalled the number of expected cases (the mean number of cases during the previous year, with extreme values excluded). We compared yearly and monthly infection rates by Poisson regression, using site-specific NIs as a dependent variable and year and month as dummy variables. We tested annual trends with an alternative Poisson regression model fitting a single linear trend.

Results.

The average rate of catheter-associated urinary tract infections was 8.4 per 1000 catheter-days; that of ventilator-associated pneumonia, 21 per 1000 ventilator-days; and that of central line–associated bloodstream infections, 30 per 1000 central line–days. The rate of urinary tract infections did not change over the study period, but there was a trend toward decreases in the rates of central line–associated bloodstream infections and ventilator-associated pneumonia.

Conclusion.

An NI surveillance and control program contributed to a progressive decrease in NI rates.

Temporal Patterns of Circulating Inflammation Biomarker Networks Differentiate Susceptibility to Nosocomial Infection Following Blunt Trauma in Humans

BACKGROUND

Severe traumatic injury can lead to immune dysfunction that renders trauma patients susceptible to nosocomial infections (NI) and prolonged intensive care unit (ICU) stays. We hypothesized that early circulating biomarker patterns following trauma would correlate with sustained immune dysregulation associated with NI and remote organ failure.

METHODS

In a cohort of 472 blunt trauma survivors studied over an 8-year period, 127 patients (27%) were diagnosed with NI versus 345 trauma patients without NI. To perform a pairwise, case-control study with 1:1 matching, 44 of the NI patients were compared with 44 no-NI trauma patients selected by matching patient demographics and injury characteristics. Plasma obtained upon admission and over time were assayed for 26 inflammatory mediators and analyzed for the presence of dynamic networks.

RESULTS

Significant differences in ICU length of stay (LOS), hospital LOS, and days on mechanical ventilation were observed in the NI patients versus no-NI patients. Although NI was not detected until day 7, multiple mediators were significantly elevated within the first 24 hours in patients who developed NI. Circulating inflammation biomarkers exhibited 4 distinct dynamic patterns, of which 2 clearly distinguish patients destined to develop NI from those who did not. Mediator network connectivity analysis revealed a higher, coordinated degree of activation of both innate and lymphoid pathways in the NI patients over the initial 24 hours.

CONCLUSIONS

These studies implicate unique dynamic immune responses, reflected in circulating biomarkers that differentiate patients prone to persistent critical illness and infections following injury, independent of mechanism of injury, injury severity, age, or sex.

Mitochondrial damage-associated molecular patterns released by abdominal trauma suppress pulmonary immune responses

BACKGROUND

Historically, fever, pneumonia, and sepsis after trauma are ascribed to pain and poor pulmonary toilet. No evidence supports that assertion however, and no known biologic mechanisms link injury to infection. Our studies show that injured tissues release mitochondria (MT). Mitochondrial damage-associated molecular patterns (mtDAMPs) however can mimic bacterial pathogen-associated danger molecules and attract neutrophils (PMN). We hypothesized that mtDAMPs from traumatized tissue divert neutrophils from the lung, causing susceptibility to infection.

METHODS

Anesthetized rats (6-10 per group) underwent pulmonary contusion (PC) by chest percussion. When modeling traumatic MT release, some rats had MT isolated from the liver (equal to 5% liver necrosis) injected intraperitoneally (IPMT). Negative controls had PC plus buffer intraperitoneally. Positive controls underwent PC plus cecal ligation and puncture. At 16 hours, bronchoalveolar and peritoneal lavages were performed. Bronchoalveolar lavage fluid (BALF) and peritoneal lavage fluid were assayed for PMN count, albumin, interleukin β, (IL-β), and CINC-1. Assays were normalized to blood urea nitrogen to calculate absolute concentrations.

RESULTS

PC caused alveolar IL-1β and CINC production and a 34-fold increase in BALF neutrophils. As expected, IPMT increased peritoneal IL-1β and CINC and attracted PMN to the abdomen. However, remarkably, IPMT after PC attenuated BALF cytokine accumulation and decreased BALF PMN. Cecal ligation and puncture had no direct effect on BALF PMNs but, like IPMT, blunted BALF leukocytosis after PC.

CONCLUSION

Rather than acting as a "second hit" to enhance PMN-mediated lung injury, mtDAMPs from trauma and pathogen-associated danger molecules from peritoneal infection diminish PMN accumulation in a contused lung. This may make the lung susceptible to pneumonia. This paradigm provides a novel mechanistic model of the relationship among blunt tissue trauma, systemic inflammation, and pneumonia that can be studied to improve trauma outcomes.

Enhancing the fever workup utilizing a multi-technique modeling approach to diagnose infections more accurately

BACKGROUND

Differentiation between infectious and non-infectious etiologies of the systemic inflammatory response syndrome (SIRS) in trauma patients remains elusive. We hypothesized that mathematical modeling in combination with computerized clinical decision support would assist with this differentiation. The purpose of this study was to determine the capability of various mathematical modeling techniques to predict infectious complications in critically ill trauma patients and compare the performance of these models with a standard fever workup practice (identifying infections on the basis of fever or leukocytosis).

METHODS

An 18-mo retrospective database was created using information collected daily from critically ill trauma patients admitted to an academic surgical and trauma intensive care unit. Two hundred forty-three non-infected patient-days were chosen randomly to combine with the 243 infected-days, which created a modeling sample of 486 patient-days. Utilizing ten variables known to be associated with infectious complications, decision trees, neural networks, and logistic regression analysis models were created to predict the presence of urinary tract infections (UTIs), bacteremia, and respiratory tract infections (RTIs). The data sample was split into a 70% training set and a 30% testing set. Models were compared by calculating sensitivity, specificity, positive predictive value, negative predictive value, overall accuracy, and discrimination.

RESULTS

Decision trees had the best modeling performance, with a sensitivity of 83%, an accuracy of 82%, and a discrimination of 0.91 for identifying infections. Both neural networks and decision trees outperformed logistic regression analysis. A second analysis was performed utilizing the same 243 infected days and only those non-infected patient-days associated with negative microbiologic cultures (n = 236). Decision trees again had the best modeling performance for infection identification, with a sensitivity of 79%, an accuracy of 83%, and a discrimination of 0.87.

CONCLUSION

The use of mathematical modeling techniques beyond logistic regression can improve the robustness and accuracy of predicting infections in critically ill trauma patients. Decision tree analysis appears to have the best potential to use in assisting physicians in differentiating infectious from non-infectious SIRS.

Infectious complications after vehicular trauma in the United States

BACKGROUND

The purpose of this analysis was to evaluate and define the rates of infectious complications (IC) after vehicular trauma. Secondary goals were to identify the injuries associated with the greatest risk of nosocomial infection and to measure the utilization of hospital resources associated with IC and vehicular trauma.

METHODS

A secondary analysis of the Nationwide Inpatient Sample (2003-2007) was performed to classify major vehicular trauma injuries utilizing International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) Emergency (E) codes. The post-traumatic IC evaluated were pneumonia, urinary tract infection (UTI), sepsis, and surgical site infection (SSI). All data were analyzed by χ(2) analysis, multivariable logistic regression, and the Cochran-Armitage test for trends.

RESULTS

A total of 784,037 vehicular trauma patients were identified (462,543 [59.0%] motor vehicle drivers, 142,283 [18.2%] motor vehicle passengers, 98,767 [12.6%] motorcyclists; 6,568 [<1%] motorcycle passengers, and 73,876 [9.4%] pedestrians). Of those sustaining injuries, 44,331 [5.7%] had post-traumatic IC. Pneumonia and UTI were most common after spinal cord injury (SCI), whereas sepsis and SSI were most common after colon injuries. After adjustment by age, sex, and co-morbidities, patients with SCI were 4.4 times as likely (95% confidence interval [CI] 4.20-4.63) and those with cranial injuries were 2.1 times as likely (95% CI 2.06-2.19) to develop IC as patients without these injuries. Secondary infection increased significantly the length of stay and hospital charges in all groups.

CONCLUSIONS

Patients sustaining vehicular trauma in combination with SCI had the highest rate of IC. Infectious complications increased hospital resource utilization significantly after vehicular trauma. Future root-cause analysis of high-risk groups may decrease complications and hospital utilization.

Increases in mortality, length of stay, and cost associated with hospital-acquired infections in trauma patients

OBJECTIVE

To explore the clinical impact and economic burden of hospital-acquired infections (HAIs) in trauma patients using a nationally representative database.

DESIGN

Retrospective study.

SETTING

The Healthcare Cost and Utilization Project Nationwide Inpatient Sample.

PATIENTS

Trauma patients.

MAIN OUTCOME MEASURES

We examined the association between HAIs (sepsis, pneumonia, Staphylococcus infections, and Clostridium difficile- associated disease) and in-hospital mortality, length of stay, and inpatient costs using logistic regression and generalized linear models.

RESULTS

After controlling for patient demographics, mechanism of injury, injury type, injury severity, and comorbidities, we found that mortality, cost, and length of stay were significantly higher in patients with HAIs compared with patients without HAIs. Patients with sepsis had a nearly 6-fold higher odds of death compared with patients without an HAI (odds ratio, 5.78; 95% confidence interval, 5.03-6.64; P < .001). Patients with other HAIs had a 1.5- to 1.9-fold higher odds of mortality compared with controls (P < .005). Patients with HAIs had costs that were approximately 2- to 2.5-fold higher compared with patients without HAIs (P < .001). The median length of stay was approximately 2-fold higher in patients with HAIs compared with patients without HAIs (P < .001).

CONCLUSIONS

Trauma patients with HAIs are at increased risk for mortality, have longer lengths of stay, and incur higher inpatient costs. In light of the preventability of many HAIs and the magnitude of the clinical and economic burden associated with HAIs, policies aiming to decrease the incidence of HAIs may have a potentially large impact on outcomes in injured patients.

Surgical site infection in abdominal trauma patients: risk prediction and performance of the NNIS and SENIC indexes

BACKGROUND

The National Nosocomial Infections Surveillance (NNIS) and Efficacy of Nosocomial Infection Control (SENIC) indexes are designed to develop control strategies and to reduce morbidity and mortality rates resulting from infections in surgical patients. We sought to assess the application of these indexes in patients undergoing surgery for abdominal trauma and to develop an alternative model to predict surgical site infections (SSIs).

METHODS

We conducted a prospective cohort study between November 2000 and March 2002. The main outcome measure was SSIs. We evaluated the variables included in the NNIS and SENIC indexes and some preoperative, intraoperative and postoperative variables that could be risk factors related to the development of SSIs. We performed multivariate analyses using a forward logistic regression method. Finally, we assessed infection risk prediction, comparing the estimated probabilities with actual occurrence using the areas under the receiver operating characteristic (ROC) curves.

RESULTS

Overall, 614 patients underwent an exploratory laparotomy. Of these, 85 (13.8%) experienced deep incisional and organ/intra-abdominal SSIs. The independent variables associated with this complication were an Abdominal Trauma Index score greater than 24, abdominal contamination and admission to the intensive care unit. We proposed a model for predicting deep incisional and organ/intra-abdominal SSIs using these variables (alternative model). The areas under the ROC curves were compared using the estimated probabilities for this alternative model and for the NNIS and SENIC scores. The analysis revealed a greater area under the ROC curve for the alternative model. The NNIS and SENIC scores did not perform as well as the alternative model in patients with abdominal trauma.

CONCLUSION

The NNIS and SENIC indexes were inferior to the proposed alternative model for predicting SSIs in patients undergoing surgery for abdominal trauma.

Systematic review of emergency department central venous and arterial catheter infection

Background

There is an extensive critical care literature for central venous catheter and arterial line infection, duration of catheterization, and compliance with infection control procedures. The emergency medicine literature, however, contains very little data on central venous catheters and arterial lines. As emergency medicine practice continues to incorporate greater numbers of critical care procedures such as central venous catheter placement, infection control is becoming a greater issue.

Aims

We performed a systematic review of studies reporting baseline data of ED-placed central venous catheters and arterial lines using multiple search methods.

Methods

Two reviewers independently assessed included studies using explicit criteria, including the use of ED-placed invasive lines, the presence of central line-associated bloodstream infection, and excluded case reports and review articles. Finding significant heterogeneity among studies, we performed a qualitative assessment.

Results

Our search produced 504 abstracts, of which 15 studies were evaluated, and 4 studies were excluded because of quality issues leaving 11 cohort studies. Four studies calculated infection rates, ranging 0–24.1/1,000 catheter-days for central line-associated and 0–32.8/1,000 catheter-days for central line-related bloodstream infection. Average duration of catheterization was 4.9 days (range 1.6–14.1 days), and compliance with infection control procedures was 33–96.5%. The data were too poor to compare emergency department to in-hospital catheter infection rates.

Conclusions

The existing data for emergency department-placed invasive lines are poor, but suggest they are a source of infection, remain in place for a significant period of time, and that adherence to maximum barrier precautions is poor. Obtaining accurate rates of infection and comparison between emergency department and inpatient lines requires prospective study.

Nature of myeloid cells expressing arginase 1 in peripheral blood after trauma

BACKGROUND

Myeloid cells that express arginase 1 are upregulated by different stimuli, including trauma, and are capable of depleting arginine from the surrounding environment. Through arginine depletion, myeloid cells are capable of regulating T-cell function. We have previously reported increased arginase 1 expression in the peripheral blood mononuclear cells (PBMCs) after injury. The nature of the cells expressing arginase in humans after trauma is unknown and is the focus of this article.

METHODS

PBMCs were isolated using a Ficoll-Hypaque gradient. Arginase activity was measured by conversion of arginine to ornithine, and arginase 1 protein expression was measured by Western blot. The percent CD16 granulocytes and phenotypical analysis of the cells present in PBMCs were determined by flow cytometry. Magnetic microbeads were used for isolation and exclusion of specific cell subpopulations.

RESULTS

Trauma patients exhibited a dramatic increase in arginase activity (p < 0.05) and an increased percentage of CD16 granulocytes in the PBMC layer (p < 0.05) compared with control volunteers. Increased arginase activity in the PBMC layer was due to the contamination of this layer by granulocytes, as their exclusion decreased arginase activity back to baseline (p < 0.05). Granulocytes isolated from the PBMC layer expressed increased CD11b (p < 0.05) and CD66b (p < 0.05), markers of granulocyte activation. Furthermore, these granulocytes were significantly more swollen and degranulated compared with noncontaminating granulocytes.

CONCLUSION

In humans, increased arginase 1 expression after trauma observed in the PBMC layer seems to be exclusively the result of an increased number of activated granulocytes.

Trauma sepsis

Sepsis is a major cause of mortality and morbidity in the trauma patient. Sepsis following traumatic injury is related to the type of injury, together with the extent of injury and the anatomical location. Burn injuries are associated with the highest risk of sepsis. The diagnosis of sepsis in the trauma patient remains difficult. Interpretation of abnormal results is key to successful diagnosis, particularly in conjunction with clinical findings. This review will consider the specific features of sepsis in the context of trauma relating to epidemiology, risk factors, diagnosis and management.

Ten years of new injury severity score (NISS): is it a possible change?

The article is a bibliographic review which intends to present the actual range of researches comparing the Injury Severity Score (ISS) and the New Injury Severity Score (NISS). Databases were searched using the keyword NISS, with 42 articles, 23 of which didn't compare the two indexes. Most part of the 19 selected articles showed that NISS has been more accurate in predicting the outcomes (dependent variables) than ISS, moreover in severe and specific trauma. Studies with populations between 1,000 and 10,000 resulted in NISS-favorable results, whereas studies with populations larger than 10,000 or smaller than 1,000 showed either NISS-favorable results or no difference between the two groups. However, there were no studies showing ISS-favorable results. These results and the easier calculation of NISS lead to a future replacement of ISS by NISS.

Ventilator-associated pneumonia in adults in developing countries: a systematic review

BACKGROUND

Ventilator-associated pneumonia (VAP) is a leading cause of death in hospitalized patients, but there has been no systematic analysis of the incidence, microbiology, and outcome of VAP in developing countries or of the interventions most applicable in that setting.

METHODS

We reviewed MEDLINE (January 1966-April 2007) and bibliographies of the retrieved articles for all observational or interventional studies that examined the incidence, microbiology, outcome, and prevention of VAP in ventilated adults in developing countries. We evaluated the rates of VAP using the National Healthcare Safety Network (NHSN) definitions and the impact of VAP on the intensive care unit (ICU) length of stay (LOS) and mortality, and the impact of interventions used to reduce VAP rates.

RESULTS

The rates of VAP varied from 10 to 41.7 per 1000 ventilator-days and were generally higher than NHSN benchmark rates. Gram-negative bacilli were the most common pathogens (41-92%), followed by Gram-positive cocci (6-58%). VAP was associated with a crude mortality that ranged from 16% to 94% and with increased ICU LOS. Only a small number of VAP intervention studies were performed; these found that staff education programs, implementation of hand hygiene, and VAP prevention practice guidelines, and/or implementation of sedation protocol were associated with a significant reduction in VAP rates. Only one interventional study was a randomized controlled trial comparing two technologies, the rest were sequential observational. This study compared a heat and moisture exchanger (HME) to a heated humidifying system (HHS) and found no difference in VAP rates.

CONCLUSIONS

Based on the existing literature, the rate of VAP in developing countries is higher than NHSN benchmark rates and is associated with a significant impact on patient outcome. Only a few studies reported successful interventions to reduce VAP. There is a clear need for additional epidemiologic studies to better understand the scope of the problem. Additionally, more work needs to be done on strategies to prevent VAP, probably with emphasis on practical, low-cost, low technology, easily implemented measures.

Fever and leukocytosis in critically ill trauma patients: it's not the urine

BACKGROUND

Infectious complications are a major cause of morbidity and mortality in critically ill trauma patients. Therefore, fever and leukocytosis often trigger an extensive laboratory workup that includes a urine culture (UCx). The purposes of this study were to: 1) Define the current practice for obtaining UCxs in trauma patients admitted to the surgical and trauma intensive care unit (STICU); and 2) determine if there is an association between fever or leukocytosis and urinary tract infections (UTIs) during the initial 14 hospital days.

METHODS

An 18-month retrospective cohort analysis was performed on consecutive trauma patients admitted for at least two days to the STICU at a level I trauma center. Data collected included demographics, injuries, and daily maximal temperature (T(max)), leukocyte count, and UCx results for the first 14 days. Fever and leukocytosis were defined as T(max) > or =38.5 degrees C and leukocyte count > or =12,000/mm(3), respectively. Urinary tract infections were diagnosed with a positive UCx (> or =10(5) organisms/mL of urine).

RESULTS

Five hundred ten patients were evaluated for a total of 3,839 patient-days. Their mean age and Injury Severity Score were 49 +/- 1 years and 19 +/- 1 points, respectively. Seventy-two percent were men, and 91% had sustained blunt injuries. Four hundred seven UCxs were obtained; 42 patients (8%) had 60 UTIs. The cohort had an indwelling urinary catheter for 97% of the patient-days, yielding an infection density of 16 UTIs/1,000 urinary catheter-days. There was a significant association between obtaining a UCx and fever and between fever and leukocytosis (both, p < 0.001), but no association of UTI with fever, leukocytosis, or the combination of fever and leukocytosis. Analysis using temperature and leukocyte count as continuous variables identified no temperature or leukocyte range associated with UTIs. Independent risk factors for UTI calculated by logistic regression were female sex, older age, low Injury Severity Score, and no antibiotics within 24 h before the UCx was obtained.

CONCLUSIONS

The practice of obtaining a UCx from the STICU trauma patient was related to fever and fever with leukocytosis. However, neither fever nor leukocytosis nor both were associated with UTIs. These data suggest that there is an unnecessary emphasis on UTI as a source of fever and leukocytosis in injured patients during their first 14 STICU days. Our results suggest that the paradigm for evaluating UTI as a cause of fever needs to be reevaluated in critically ill trauma patients.

A Six-Year Descriptive Study of Hospital-Associated Infection in Trauma Patients: Demographics, Injury Features, and Infection Patterns

BACKGROUND AND PURPOSE

Hospital-associated infection (HAI) is of concern to surgeons providing care for traumatized patients, as such patients have a higher rate of infection than other patients. Infection surveillance programs often study trauma patients within other populations (e.g., intensive care unit [ICU], surgery), and important issues may be missed. Information identifying trauma patients at risk, most frequent infection sites, and pathogens is of importance for surveillance and infection control. Measurement is essential to improving care.

METHODS

We evaluated the HAI rate, demographics, injury characteristics, and HAI patterns (microorganisms, sites, antibiotics) in trauma patients (1996-2001). We used two-tailed Mann-Whitney and Fisher exact tests for univariate analysis and a stepwise multivariable logistic regression model for association of multiple variables with the development of HAI.

RESULTS

The incidence of HAI was 501 (9.1%) in 5,537 patients. Trauma patients with HAI were older (p < 0.001), more severely injured (p < 0.001), and more likely to have multi-system trauma (p = 0.027). Development of HAI was associated with all injury sites except the face. The most common pathogens were gram-positive cocci, and the most common infection sites were urinary and respiratory, with 157 of 501 (31%) being ventilator-associated pneumonia. The antibiotics most commonly used were cephalosporins and fluoroquinolones. Of 5,537 trauma patients, 19 (0.3%) had Staphylococcus aureus resistant to methicillin, which was higher (p < 0.001) than in the non-trauma patients (176 in 146,727 [0.1%]).

CONCLUSIONS

Hospital-associated infections occur frequently in trauma patients. This paper identifies populations to target for surveillance and HAI control initiatives. With increased interest in adverse event prevention and continuing quality of care improvement, these data provide a benchmark for this institution and others.

Incidence study of nosocomial infection in pediatric trauma patients

In this article we intend to describe the epidemiological profile of nosocomial infection in pediatric patients with multiple trauma. We conducted a prospective study from July to November 2003 in a pediatric teaching hospital in Barcelona. We used US Centers for Disease Control and Prevention standard criteria to define nosocomial infection. Of the 121 patients included in the study, 33% had at least one episode of nosocomial infection, with an incidence rate of 9.9 infections per 100 admissions and 1.1 infections per 100 patient-days. The most frequent episode of nosocomial infection was bacteremia. Coagulase-negative staphylococci were the most common pathogens. Nosocomial infection rates per 100 device-days were 3.2 for bacteremia, 1.6 for respiratory infection and 1.0 for urinary tract infection. These findings suggest the need to evaluate infection control measures aimed at reducing the morbidity associated with infections.

Do proton pump inhibitors increase the incidence of nosocomial pneumonia and related infectious complications when compared with histamine-2 receptor antagonists in critically ill trauma patients?

BACKGROUND

Proton pump inhibitors (PPI) may increase the risk of nosocomial pneumonia caused by profound irreversible gastric acid suppression. The study purpose was to characterize differences in nosocomial pneumonia and related infections in trauma patients administered either histamine2-receptor antagonists (H2RA) or PPI.

METHODS

Observational evaluation of consecutive critically ill adult trauma patients administered either omeprazole or famotidine during a 22-month period. Nosocomial infection was evaluated daily based on published CDC definitions.

RESULTS

Eighty of 269 patients fulfilled study criteria. The PPI group (n = 40) exhibited increased baseline risk for infection, demonstrated by higher ISS (p = 0.020), more chest tube placements (p = 0.031), and increased chest trauma (p = 0.025). Overall number of patients infected per group included 33% and 40% of patients administered PPI and H2RA, respectively (p = 0.64). Despite baseline differences, the incidence of nosocomial infection was similar (p = 0.87), and extrapolation of pneumonia based on 1000 patient days revealed a ratio 51.7 vs 52.2 in the PPI vs H2RA groups, respectively, which was not significant (p = 0.99).

CONCLUSIONS

Proton pump inhibitor administration does not increase risk of nosocomial pneumonia or other nosocomial infections compared with H2RA therapy in the critically ill trauma patient.