Charles B. Cairns

Ethical and Scientific Implications of the Globalization of Clinical Research

In recent years, the number of clinical trials conducted in the United States has declined, and the majority of study sites are now outside the United States, with marked growth of research in developing countries. The authors discuss the implications of the globalization of clinical research and make recommendations about how to address the challenges that have emerged.

Preconditioning against myocardial dysfunction after ischemia and reperfusion by an alpha 1-adrenergic mechanism.

Preconditioning may find ready applicability in humans facing scheduled global cardiac ischemia-reperfusion (IR) during bypass or transplantation, where such a maneuver is feasible before arrest. Our objective was to delineate and exploit the endogenous preconditioning mechanism triggered by transient ischemia (TI) and thereby attenuate myocardial postischemic mechanical dysfunction by clinically acceptable means. Preconditioning by 2 minutes of TI followed by 10 minutes of normal perfusion protected isolated rat left ventricle function assessed after 20 minutes of global, 37 degrees C ischemia and 40 minutes of reperfusion. Final recovery of developed pressure (DP) was improved (91.5 +/- 1.9% of equilibration DP versus unconditioned IR control, 57.4 +/- 2.4%, P < .01) and was accompanied by increased contractility (+/- dP/dt). Norepinephrine release increased after TI, and reserpine pretreatment abolished TI preconditioning. This suggests that endogenous norepinephrine mediates functional preconditioning in rat. Brief pretreatment (2 minutes) with exogenous norepinephrine reproduced the protection (89.1 +/- 1.4%) of postischemic function. Functional protection persisted after the hemodynamic effects had resolved. Norepinephrine-induced preconditioning was simulated by phenylephrine and blocked by alpha 1-adrenergic receptor antagonist. TI preconditioning was similarly lost after selective alpha 1-adrenergic receptor blockade. We conclude that transient ischemic preconditioning is mediated by the sympathetic neurotransmitter release and alpha 1-adrenergic receptor stimulation. Although the postreceptor mechanism remains unclear, functional protection after IR does not seem related to the magnitude of ATP depletion and elevation of resting pressure during ischemia. Rather, the endogenous mechanisms facilitate both recovery of mechanical function and ATP repletion during reperfusion.

Sepsis: An integrated clinico-metabolomic model improves prediction of death in sepsis

A molecular signature, derived from integrated analysis of clinical data, the metabolome, and the proteome in prospective human studies, improved the prediction of death in patients with sepsis, potentially identifying a subset of patients who merit intensive treatment. Understanding Survival of the Fittest in Sepsis Differentiating mild infections from life-threatening ones is a complex decision that is made millions of times a year in U.S. emergency rooms. Should a patient be sent home with antibiotics and chicken soup? Or should he or she be hospitalized for intensive treatment? Sepsis—a serious infection that is associated with a generalized inflammatory response—is one of the leading causes of death. In two prospective clinical studies reported by Langley et al., patients arriving at four urban emergency departments with symptoms of sepsis were evaluated clinically and by analysis of their plasma proteome and metabolome. Survivors and nonsurvivors at 28 days were compared, and a molecular signature was detected that appeared to differentiate these outcomes—even as early as the time of hospital arrival. The signature was part of a large set of differences between these groups, showing that better energy-producing fatty acid catabolism was associated with survival of the fittest in sepsis. A test developed from the signature was able to predict sepsis survival and nonsurvival reproducibly and better than current methods. This test could help to make all important decisions in the emergency room more accurate. Sepsis is a common cause of death, but outcomes in individual patients are difficult to predict. Elucidating the molecular processes that differ between sepsis patients who survive and those who die may permit more appropriate treatments to be deployed. We examined the clinical features and the plasma metabolome and proteome of patients with and without community-acquired sepsis, upon their arrival at hospital emergency departments and 24 hours later. The metabolomes and proteomes of patients at hospital admittance who would ultimately die differed markedly from those of patients who would survive. The different profiles of proteins and metabolites clustered into the following groups: fatty acid transport and β-oxidation, gluconeogenesis, and the citric acid cycle. They differed consistently among several sets of patients, and diverged more as death approached. In contrast, the metabolomes and proteomes of surviving patients with mild sepsis did not differ from survivors with severe sepsis or septic shock. An algorithm derived from clinical features together with measurements of five metabolites predicted patient survival. This algorithm may help to guide the treatment of individual patients with sepsis.

A prospective, multicenter derivation of a biomarker panel to assess risk of organ dysfunction, shock, and death in emergency department patients with suspected sepsis

Objective:To define a biomarker panel to predict organ dysfunction, shock, and in-hospital mortality in emergency department (ED) patients with suspected sepsis. Design:Prospective observational study. Setting:EDs of ten academic medical centers. Patients:There were 971 patients enrolled. Inclusion criteria: 1) ED patients age > 18; 2) suspected infection or a serum lactate level > 2.5 mmol/L; and 3) two or more systemic inflammatory response syndrome criteria. Exclusion criteria: pregnancy, do-not-resuscitate status, or cardiac arrest. Measurements and Main Results:Nine biomarkers were assayed from blood draws obtained on ED presentation. Multivariable logistic regression was used to identify an optimal combination of biomarkers to create a panel. The derived formula for weighting biomarker values was used to calculate a “sepsis score,” which was the predicted probability of the primary outcome of severe sepsis (sepsis plus organ dysfunction) within 72 hrs. We also assessed the ability of the sepsis score to predict secondary outcome measures of septic shock within 72 hrs and in-hospital mortality. The overall rates of each outcome were severe sepsis, 52%; septic shock, 39%; and in-hospital mortality 7%. Among the nine biomarkers tested, the optimal 3-marker panel was neutrophil gelatinase-associated lipocalin, protein C, and interleukin−1 receptor antagonist. The area under the curve for the accuracy of the sepsis score derived from these three biomarkers was 0.80 for severe sepsis, 0.77 for septic shock, and 0.79 for death. When included in multivariate models with clinical variables, the sepsis score remained highly significant (p < 0.001) for all the three outcomes. Conclusions:A biomarker panel of neutrophil gelatinase-associated lipocalin, interleukin-1ra, and Protein C was predictive of severe sepsis, septic shock, and death in ED patients with suspected sepsis. Further study is warranted to prospectively validate the clinical utility of these biomarkers and the sepsis score in risk-stratifying patients with suspected sepsis.

Evidence for early supply independent mitochondrial dysfunction in patients developing multiple organ failure after trauma.

OBJECTIVE To determine whether early supply independent mitochondrial oxidative dysfunction occurs in trauma patients who develop multiple organ failure (MOF). DESIGN Prospective focused observational trial. METHODS High-risk patients were aggressively resuscitated while being continuously monitored by near infrared spectroscopy. Near infrared spectroscopy monitoring strips allow for a direct comparison of changes in tissue oxyhemoglobin levels (HbO2), which reflect local oxygen supply, and cytochrome a,a3 redox, which reflects mitochondrial oxygen consumption. Under normal conditions, HbO2 and a,a3 redox are tightly coupled. On the other hand, decoupled HbO2 and a,a3 redox is a sign of mitochondrial oxidative dysfunction. Outcomes included MOF, oxygen delivery, oxygen consumption, lactate, and the presence of decoupled HbO2 and a,a3 redox. RESULTS Twenty-four high-risk patients were studied; nine (38%) developed MOF. At 12 hours of resuscitation, MOF and non-MOF patients did not have statistically different oxygen delivery and oxygen consumption, but lactate levels were significantly higher in MOF patients. Additionally, HBO2 and a,a3 redox were decoupled in eight (89%) MOF patients compared with two (13%) non-MOF patients (p < 0.05). CONCLUSION Severely injured trauma patients who develop MOF preferentially display evidence of mitochondrial oxidative dysfunction early in the course of their resuscitation despite early goal-oriented maximization of oxygen delivery.

The Diagnostic Accuracy of Plasma Neutrophil Gelatinase–Associated Lipocalin in the Prediction of Acute Kidney Injury in Emergency Department Patients With Suspected Sepsis

STUDY OBJECTIVE We assess the diagnostic accuracy of plasma neutrophil gelatinase-associated lipocalin (NGAL) to predict acute kidney injury in emergency department (ED) patients with suspected sepsis. METHODS We conducted a secondary analysis of a prospective observational study of a convenience sample of patients from 10 academic medical center EDs. Inclusion criteria were adult patients aged 18 years or older, with suspected infection or a serum lactate level greater than 2.5 mmol/L; 2 or more systemic inflammatory response syndrome criteria; and a subsequent serum creatinine level obtained within 12 to 72 hours of enrollment. Exclusion criteria were pregnancy, do-not-resuscitate status, cardiac arrest, or dialysis dependency. NGAL was measured in plasma collected at ED presentation. Acute kidney injury was defined as an increase in serum creatinine measurement of greater than 0.5 mg/dL during 72 hours. RESULTS There were 661 patient enrolled, with 24 cases (3.6%) of acute kidney injury that developed within 72 hours after ED presentation. Median plasma NGAL levels were 134 ng/mL (interquartile range 57 to 277 ng/mL) in patients without acute kidney injury and 456 ng/mL (interquartile range 296 to 727 ng/mL) in patients with acute kidney injury. Plasma NGAL concentrations of greater than 150 ng/mL were 96% sensitive (95% confidence interval [CI] 79% to 100%) and 51% (95% CI 47% to 55%) specific for acute kidney injury. In comparison, to achieve equivalent sensitivity with initial serum creatinine level at ED presentation required a cutoff of 0.7 mg/dL and resulted in specificity of 17% (95% CI 14% to 20%). CONCLUSION In this preliminary investigation, increased plasma NGAL concentrations measured on presentation to the ED in patients with suspected sepsis were associated with the development of acute kidney injury. Our findings support NGAL as a promising new biomarker for acute kidney injury; however, further research is warranted.

Multiplex PCR to diagnose bloodstream infections in patients admitted from the emergency department with sepsis.

ABSTRACT Sepsis is caused by a heterogeneous group of infectious etiologies. Early diagnosis and the provision of appropriate antimicrobial therapy correlate with positive clinical outcomes. Current microbiological techniques are limited in their diagnostic capacities and timeliness. Multiplex PCR has the potential to rapidly identify bloodstream infections and fill this diagnostic gap. We identified patients from two large academic hospital emergency departments with suspected sepsis. The results of a multiplex PCR that could detect 25 bacterial and fungal pathogens were compared to those of blood culture. The results were analyzed with respect to the likelihood of infection, sepsis severity, the site of infection, and the effect of prior antibiotic therapy. We enrolled 306 subjects with suspected sepsis. Of these, 43 were later determined not to have infectious etiologies. Of the remaining 263 subjects, 70% had sepsis, 16% had severe sepsis, and 14% had septic shock. The majority had a definite infection (41.5%) or a probable infection (30.7%). Blood culture and PCR performed similarly with samples from patients with clinically defined infections (areas under the receiver operating characteristic curves, 0.64 and 0.60, respectively). However, blood culture identified more cases of septicemia than PCR among patients with an identified infectious etiology (66 and 46, respectively; P = 0.0004). The two tests performed similarly when the results were stratified by sepsis severity or infection site. Blood culture tended to detect infections more frequently among patients who had previously received antibiotics (P = 0.06). Conversely, PCR identified an additional 24 organisms that blood culture failed to detect. Real-time multiplex PCR has the potential to serve as an adjunct to conventional blood culture, adding diagnostic yield and shortening the time to pathogen identification.

Ischemia alone is sufficient to induce TNF-alpha mRNA and peptide in the myocardium.

Over-production of tumor necrosis factor-alpha (TNF-&agr;) following myocardial ischemia-reperfusion contributes to cardiac dysfunction, and anti-TNF-&agr; has therapeutic potential for myocardial protection in cardiac surgery with obligatory ischemia. It remains unclear, however, whether myocardial TNF-&agr; production occurs during ischemia and whether cardiac myocytes constitute a source of myocardial TNF-&agr;. Ischemia alone has been shown to activate myocardial NF-&kgr;B. We hypothesized that ischemia alone is sufficient to induce myocardial TNF-&agr; gene expression and peptide synthesis. We examined TNF-&agr; production and NF-&kgr;B activation in the isolated rat heart subjected to global normothermic ischemia. Myocardial ischemia resulted in rapid I&kgr;B-&agr; degradation and NF-&kgr;B activation. Immunofluorescence staining detected NF-&kgr;B intranuclear translocation primarily in myocardial interstitial cells. Ischemia alone induced a time-dependent increase in myocardial TNF-&agr;. TNF-&agr; peptide increased to 20.3 ± 3.0 pg/mg after 25 min of ischemia (P < 0.05 vs 8.9 ± 2.0 pg/mg in perfusion control). TNF-&agr; was also localized to myocardial interstitial cells. Increased TNF-&agr; peptide level correlated with TNF-&agr; mRNA expression. We conclude that ischemia alone induces TNF-&agr; gene expression and peptide synthesis in the myocardium that are associated with NF-&kgr;B activation. Non-myocytes constitute the main source of myocardial TNF-&agr; following ischemia. The results suggest that therapeutic strategies attempting to decrease myocardial TNF-&agr; production need to be applied before or in the early phase of ischemia.

Disease Progression in Hemodynamically Stable Patients Presenting to the Emergency Department With Sepsis

BACKGROUND Aggressive diagnosis and treatment of patients presenting to the emergency department (ED) with septic shock has been shown to reduce mortality. To enhance the ability to intervene in patients with lesser illness severity, a better understanding of the natural history of the early progression from simple infection to more severe illness is needed. OBJECTIVES The objectives were to 1) describe the clinical presentation of ED sepsis, including types of infection and causative microorganisms, and 2) determine the incidence, patient characteristics, and mortality associated with early progression to septic shock among ED patients with infection. METHODS This was a multicenter study of adult ED patients with sepsis but no evidence of shock. Multivariable logistic regression was used to identify patient factors for early progression to shock and its association with 30-day mortality. RESULTS Of 472 patients not in shock at ED presentation (systolic blood pressure > 90 mm Hg and lactate < 4 mmol/L), 84 (17.8%) progressed to shock within 72 hours. Independent factors associated with early progression to shock included older age, female sex, hyperthermia, anemia, comorbid lung disease, and vascular access device infection. Early progression to shock (vs. no progression) was associated with higher 30-day mortality (13.1% vs. 3.1%, odds ratio [OR] = 4.72, 95% confidence interval [CI] = 2.01 to 11.1; p < or = 0.001). Among 379 patients with uncomplicated sepsis (i.e., no evidence of shock or any end-organ dysfunction), 86 (22.7%) progressed to severe sepsis or shock within 72 hours of hospital admission. CONCLUSIONS A significant portion of ED patients with less severe sepsis progress to severe sepsis or shock within 72 hours. Additional diagnostic approaches are needed to risk stratify and more effectively treat ED patients with sepsis.

Accuracy of the Emergency Severity Index triage instrument for identifying elder emergency department patients receiving an immediate life-saving intervention.

OBJECTIVES The study objective was to determine the sensitivity and specificity of the Emergency Severity Index (ESI) triage instrument for the identification of elder patients receiving an immediate life-saving intervention in the emergency department (ED). METHODS The authors reviewed medical records for consecutive patients 65 years or older who presented to a single academic ED serving a large community of elders during a 1-month period. ESI triage scores were compared to actual ED course with attention to the occurrence of an immediate life-saving intervention. The sensitivity and specificity of an ESI triage level of 1 for the identification of patients receiving an immediate intervention was calculated. For 50 cases, the triage nurse ESI designation was compared to the triage level determined by an expert triage nurse based on retrospective record review. RESULTS Of 782 consecutive patients 65 years or older who presented to the ED, 18 (2%) had an ESI level of 1, 176 (23%) had an ESI level of 2, 461 (60%) had an ESI level of 3, 100 (13%) had an ESI level of 4, and 18 (2%) had an ESI level of 5. Twenty-six patients received an immediate life-saving intervention. ESI triage scores for these 26 individuals were as follows: ESI 1, 11 patients; ESI 2, nine patients; and ESI 3, six patients. The sensitivity of ESI to identify patients receiving an immediate intervention was 42.3% (95% confidence interval [CI]=23.3% to 61.3%); the specificity was 99.2% (95% CI=98.0% to 99.7%). For 17 of 50 cases in which actual triage nurse and expert nurse ESI levels disagreed, undertriage by the triage nurses was more common than overtriage (13 vs. 4 patients). CONCLUSIONS The ESI triage instrument identified fewer than half of elder patients receiving an immediate life-saving intervention. Failure to follow established ESI guidelines in the triage of elder patients may contribute to apparent undertriage.