Global Research Review: Issue 11

Published on January 10, 2014
on behalf of the Global Emergency Medicine Literature Review Group

GLOBAL

Standardized prehospital trauma training saves lives in developing countries

Henry JA, Reingold AL. Prehospital trauma systems reduce mortality in developing countries: A systematic review and meta-analysis. J Trauma Acute Care Surg. 2012;73:261-268.

This systemic review and meta-analysis examines the published data on the effectiveness of prehospital trauma systems in emerging and developing countries. Using a comprehensive search strategy, without restrictions on language or study design, the authors identified 14 studies for the qualitative analysis, all comparing a prehospital trauma care intervention to a control group without the intervention. The mean age of the patients was 32.7 years, 77.7% were male, and 79.6% were injured by a blunt trauma mechanism. Eight studies were included in the meta-analysis. Interventions included introduction of Prehospital Trauma Life Support (6 studies), Advanced Trauma Life Support (1 study), and Basic Trauma Life Support (1 study). The interventions were associated with an overall 25% decrease in mortality (the primary outcome), with a slightly greater treatment effect in rural vs. urban settings (29% vs 21% risk reduction, respectively). Though injuries classified as “Severe” and “Critical” (by Injury Severity Scores of 16-24 and 25-75, respectively) accounted for only 23.5% of patients, they represented 96.4% of the reported fatalities. This well conducted review demonstrates the potential impact of basic prehospital trauma care interventions in emerging and developing countries. However, it should be noted that none of the included studies were randomized controlled trials and the majority (7/8) were rated as “average” study designs. Importantly, while the authors only included studies published in peer-reviewed journals, the results of the Funnel plot and Begg’s test did not suggest the presence of publication bias. Despite the limitations, the results are compelling given the significant morbidity and mortality from injuries worldwide. As such, these data should be used to engage stakeholders at the policy level to advocate for development of basic prehospital trauma care systems.

-MR, SB


CONGO

Rapid Testing for Cholera

Page AL, Alberti KP, Mondonge V, Rauzier J, Quilici ML, Guerin PJ. Evaluation of a Rapid Test for the Diagnosis of Cholera in the Absence of a Gold Standard. PLoS One. 2012;7(5):e37360.

The global incidence of cholera has been increasing in recent years. Early outbreak identification is essential for rapid implementation of essential interventions. Rapid diagnostic tests (RDT), such as the Crystal VC, offer promise for early cholera confirmation given the limited capacity in most outbreak settings for stool culture, the gold standard for diagnosis. However, as a gold standard, stool culture has limited sensitivity, which when used as a comparison can underestimate RDT specificity. In this study, the authors evaluated the Crystal VC immunochromatographic test using a modified reference standard in an ongoing cholera outbreak in the Democratic Republic of the Congo. Stool samples were collected from 296 patients at two cholera treatment centers. The RDT was performed both by a trained laboratory technician and an untrained clinician to simulate outbreak conditions. Three separate methodologies were used as the reference standard: stool culture alone, stool culture with PCR, and Bayesian analysis. PCR was used to resolve discordant results between culture and RDT to increase the sensitivity of this reference standard. Bayesian analysis, which can be used to assess test performance in the absence of a gold standard, utilized known test characteristics and its past performance. In all scenarios, the RDT had good sensitivity but limited specificity (70.6% when used by a lab technician) when compared against stool culture alone. The test specificity increased to 88.6% when compared to culture with PCR and to 85.0% in the Bayesian analysis. Given the limited lab capacity in most cholera outbreak settings, RDTs offer an important tool for early diagnosis. This study demonstrates that some of the concerns about the limited specificity of RDTs are due to the poor sensitivity of the reference test – and not to characteristics of the RDT itself. The results are limited by a small sample size, as the study outbreak waned earlier than expected. However, the conclusions that the Crystal VC has a higher specificity than initially reported are likely still valid. This information is of significant importance to global EM providers involved in the response to potential cholera outbreaks, hastening their ability to implement response measures.

-RH, MF


GLOBAL

Who is willing to work during a public health emergency?

Devnani M. Factors associated with the willingness of health care personnel to work during an influenza public health emergency: an integrative review. Prehosp Disaster Med. 2012;27(6):551-66.

Within the last decade there have been three major influenza public health emergencies: SARS, avian flu and the H1N1 pandemic influenza. Because an effective public health response to an influenza emergency depends on health care personnel (HCP) continuing to work, it is important to understand the factors that influence HCP’s intent to work during such an emergency. The objective of this integrative review article was to identify factors that influence the willingness of HCP to report to work during an influenza emergency. The author searched the Cochrane, PubMed, EBSCO, and Google Scholar databases for peer-reviewed, quantitative studies in English that were published between January 1, 2001 and June 30, 2010. Thirty-two studies from ten different countries that met predefined criteria were included. Factors associated with a willingness to work during an influenza outbreak include: being male, being a doctor or a nurse, working clinically or in an emergency department, working full-time, prior influenza education and training, prior experience of working during an influenza emergency, the perception of value in response, the belief in duty, the availability of personal protective equipment and confidence in one’s employer. Factors associated with HCP being less willing to work include: being female, holding a supportive staff position, working part-time, the peak phase of the influenza emergency, concern for family and loved ones, and personal obligations. Interventions that increased HCP willingness to work were preferential access to Tamiflu and the provision of a vaccine for HCP and their family. This review identifies numerous factors that influence the likelihood that HCP will present to work during an influenza emergency. It is the first review article to integrate the recent literature on this topic, making an important contribution to the literature on health sector human resources during infectious emergencies. A variety of factors, both positive and negative, as well as critical interventions, are identified, giving administrators and public health officials better guidance about what to expect and what they can do during such emergencies. However, the meta-analysis is limited by the highly variable quality of the included studies, equal weighting of studies despite such a range in quality, and the inclusion of only English language articles.

-JJ, HD


KENYA

Estimating the Weight of Pediatric Patients in a Low-Income Country

House DR, Ngetich E, Vreeman RC, Rusyniak DE. Estimating the weight of children in Kenya: do the Broselow tape and age based formulas measure up? Ann Emerg Med. 2013;61(1):1-8.

This prospective cross-sectional study of all children presenting to an emergency department (ED) in western Kenya sought to determine which methods of pediatric weight estimation were valid in a low-income country. The authors enrolled children (n= 967, age range 2 months to 14 years) presenting to a government referral emergency department in western Kenya. Only children who had conditions that would obviously make height or age based weight estimates inaccurate (i.e. cerebral palsy, dwarfism) were excluded. Each child had an estimated weight calculated using three methods (Broselow Tape, APLS and Nelson’s age based formulas). Bland-Altman analysis was used to determine limits of agreement. Weight estimates were defined a priori as valid if the 95% confidence interval for the mean percent difference between actual weight and estimated weight was < 10%. The Broselow tape provided the most accurate estimation of the child’s weight. In less than 1% of cases was the Broselow estimate off by two “color zones” and in >65% of children, the height correlated to the proper color zone for the actual weight. The APLS method was less accurate, but still met the definition for validity, while the Nelson method was not valid. This study has several strengths. First, the four main clinicians performing the height measurements all measured a percentage of the children at the beginning of the study and there was excellent agreement between their measurements. Additionally, the sample is size is quite large and includes children of various ages, increasing the reliability of the results. The most prominent limitation of the study is its lack of generalizability. The study site charges a fee for care, which may bias the population toward a more affluent (i.e., less likely to have malnourished children) population. Additionally, the study period did not include times of famine, so one cannot assume that any of the methods would be accurate in such settings. Finally, although there is no obvious bias, due to resource limitations, not all patients who presented to the ED were enrolled. This article compliments research that has validated the accuracy of the Broselow tape in high-income settings. These data support the use of either the Broselow tape or APLS methods to estimate weight in children presenting to the ED in a low resource setting.

-MB, ES


GLOBAL

Impact of Structured Resuscitation Training Programs

Mosley C, Dewhurst C, Molloy S, Shaw BN. What is the impact of structured resuscitation training on healthcare practitioners, their clients, and the wider service? Med Teach. 2012;34(6):e349-85.

This review article attempts the first systematic analysis of the results of structured resuscitation training programs (SRT) on participants, institutions, and patient outcomes. It uses an English language literature search surrounding the concepts of resuscitation training, clinical competence, and skill, as well as retention and outcomes. Articles where screened and reviewed by several authors with a consensus model regarding changes in protocol during the evidence gathering process. The article used a modified Kirkpatrick hierarchy (a four level model to evaluate training programs), categorizing results into level 2 (modification of attitudes/perceptions and skills), level 3 (behavioral change), or level 4 (change in organizational practice and benefits in clinical outcomes). Of 3781 articles searched, 105 articles of heterogeneous design were included in the study. Data were compiled and qualitatively reviewed based on study aim, design and sample characteristics, data analysis, and results and conclusions. Results were categorized and presented based on a modified Kirkpatrick hierarchy with divisions for neonatal, pediatric, and adult SRT. The review demonstrated that SRT consistently improves the knowledge and skill of participants and that these levels begin to deteriorate starting at three months after the trainings. In settings where SRT were institutional and no prior trainings existed, a clear improvement in mortality and clinical management was evident, suggesting a group effect. Specific groups to be trained, components of training programs, and whether or not the SRT was accredited did not impact the results. SRT programs are essential but complex, poorly understood and contentious components of global efforts in emergency medicine development. This article represents a robust attempt to systematically review and impart understanding on the heterogeneous and conflicting body of evidence with regard to educational impacts and outcomes. The results are encouraging, demonstrating improvement in knowledge and skills, mortality, and clinical management. The knowledge deterioration and presumed reduction in skills and outcomes suggests the benefits of training refreshers or regular drills, although this was not a direct result of the study. Finally, lack of clear evidence on the benefits of particular training methods or need for use of accredited programs suggests that it is likely all training has some benefit with the added benefits demonstrated when SRT was institution-wide.

-SM, TB


SOUTHERN ASIA

Zinc supplementation for acute lower respiratory tract infection in children does not improve outcomes

Das RR, Singh M, Shafiq N. Short-term therapeutic role of zinc in children <5 years of age hospitalized for severe acute lower respiratory tract infection. Ped Resp Review. 2012;13:184-191.

Routine dietary zinc supplementation has been shown to reduce the frequency of lower respiratory tract infection in children under 5 years of age. The evidence for using zinc in the treatment of acute lower respiratory tract infection (ALRTI) has not been established. This meta-analysis sought to determine whether zinc supplementation in the treatment of ALRTI has an effect in treatment outcomes. The authors describe an extensive search strategy for the selection of articles by multiple authors blinded to each other’s selections. Studies were assessed for methodological quality using standardized assessment forms. Only randomized, blinded, controlled studies utilizing a treatment and placebo group were included in the analysis. Studies were excluded if they did not directly assess the outcomes of objective improvement in respiratory illness, duration of hospitalization, adverse events or change in treatment. Studies were also excluded if they were primarily assessments of particular respiratory illnesses such as HIV or measles-related respiratory illness, or were primarily testing treatment with additional medications such as vitamin A or multiple micronutrients. Discrepancies between authors’ selections were mediated through a defined process. Of 62 studies using the selected search strategy, seven ultimately met the inclusion and exclusion criteria to include a total of 1066 children. Pooled data analysis sought to find a therapeutic effect of zinc supplementation in addition to traditional antibiotics. No statistically significant difference between the placebo and treatment groups was found in either primary or secondary treatment outcomes. This meta-analysis utilized a well-defined search strategy to answer a single research question – whether zinc supplementation improves outcomes for ALRTI. The study question is legitimate. Since zinc supplementation has been shown to reduce incidence of ALRTI, it may be reasonably assumed that zinc treatment may also improve outcomes in ALRTI. However, this study demonstrates that there is no compelling evidence to suggest that this is true. The study is reproducible given the methods described and attempts to limit bias and improve inter-rater reliability are well documented. The utilization of only randomized, blinded, placebo-controlled studies adds to the reliability of the analysis. By excluding studies that assess particular ALRTIs (measles or HIV-related lung infections) as well as studies that assess multiple treatments (multiple micronutrient supplementation) the research question is adequately narrow in focus. Despite this care in study selection, of the 62 eligible studies, only 7 met the inclusion/exclusion criteria. Four of the seven were conducted in India and all were conducted in southern Asia. All but one of the studies were conducted in tertiary or referral hospitals. This geographical bias limits the study’s generalizability to more diverse regions, countries, or treatment settings. Despite the narrow setting and low number of acceptable studies, the conclusion that zinc has no effect on the duration of ALRTI illness or associated symptoms is compelling and should result in further research, even if zinc may ultimately not be a recommended treatment modality for ALRTI.

-BH, TB


editors

MR: Michael Runyon, MD | SB: Suzanne Bartels, MD, MPH | RM: Regan H. Marsh, MD, MPH | MF: Mark Foran, MD, MPH | JM: Joshua M. Jauregui, MD | HD: Herbie Duber, MD, MPH | MB: Mark Bisanzo, MD | ES: Erika D. Schroeder, MD, MPH | TB: Torben K. Becker, MD | SM: Stephen Morris, MD, MPH | BH: Braden Hexom, MD |


This article originally appeared in issue 11 of Emergency Physicians International

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