Lorenzo Paladino

The utility of base deficit and arterial lactate in differentiating major from minor injury in trauma patients with normal vital signs

OBJECTIVES Early recognition and treatment of hemorrhagic shock after trauma limits multi-organ failure and mortality. Traditional vital signs (VS) although specific are not highly sensitive for hemorrhage detection. Metabolic parameters such as lactate and base deficit (BD) are highly sensitive indicators of blood loss by measuring tissue perfusion. Does adding information from BD and lactate to traditional VS improve the identification of trauma patients with major injuries? METHODS We conducted a retrospective study of a prospectively collected database at a Level I trauma center from January 2003 to September 2005. Patients >13 years, suspected of having significant injury by mechanism, were included. Abnormal VS were defined by heart rate >100 beats/min or systolic blood pressure <90 mmHg. Metabolic parameters from initial arterial blood gas were measured in all patients, abnormal defined by BD >-2.0 mMol/L or lactate >2.2 mMol/L. Our outcome variable, major injury, was defined as any trauma patient who received a blood transfusion, or dropped their hematocrit >10 points in the first 24 h, or had an Injury Severity Score (ISS) >15. RESULTS 1435 patients were enrolled, 242 (17%) had major injuries. Abnormal VS alone had a sensitivity of 40.9% (95% CI, 34.7-47.1%) for identifying major injury patients. When abnormal metabolic parameters were added, major injury detection increased significantly to a sensitivity of 76.4% (95% CI, 71.1-81.8%). CONCLUSIONS The addition of BD and lactate to triage vital signs increases the ability to distinguish major from minor injury.

Diagnostic Accuracy of History, Physical Examination, and Bedside Ultrasound for Diagnosis of Extremity Fractures in the Emergency Department: A Systematic Review

OBJECTIVES Understanding history, physical examination, and ultrasonography (US) to diagnose extremity fractures compared with radiography has potential benefits of decreasing radiation exposure, costs, and pain and improving emergency department (ED) resource management and triage time. METHODS The authors performed two electronic searches using PubMed and EMBASE databases for studies published between 1965 to 2012 using a strategy based on the inclusion of any patient presenting with extremity injuries suspicious for fracture who had history and physical examination and a separate search for US performed by an emergency physician (EP) with subsequent radiography. The primary outcome was operating characteristics of ED history, physical examination, and US in diagnosing radiologically proven extremity fractures. The methodologic quality of the studies was assessed using the quality assessment of studies of diagnostic accuracy tool (QUADAS-2). RESULTS Nine studies met the inclusion criteria for history and physical examination, while eight studies met the inclusion criteria for US. There was significant heterogeneity in the studies that prevented data pooling. Data were organized into subgroups based on anatomic fracture locations, but heterogeneity within the subgroups also prevented data pooling. The prevalence of fracture varied among the studies from 22% to 70%. Upper extremity physical examination tests have positive likelihood ratios (LRs) ranging from 1.2 to infinity and negative LRs ranging from 0 to 0.8. US sensitivities varied between 85% and 100%, specificities varied between 73% and 100%, positive LRs varied between 3.2 and 56.1, and negative LRs varied between 0 and 0.2. CONCLUSIONS Compared with radiography, EP US is an accurate diagnostic test to rule in or rule out extremity fractures. The diagnostic accuracy for history and physical examination are inconclusive. Future research is needed to understand the accuracy of ED US when combined with history and physical examination for upper and lower extremity fractures.

Systematic Review: Emergency Department Bedside Ultrasonography for Diagnosing Suspected Abdominal Aortic Aneurysm

BACKGROUND The use of ultrasound (US) to diagnose an abdominal aortic aneurysm (AAA) has been well studied in the radiology literature, but has yet to be rigorously reviewed in the emergency medicine arena. OBJECTIVES This was a systematic review of the literature for the operating characteristics of emergency department (ED) ultrasonography for AAA. METHODS The authors searched PubMed and EMBASE databases for trials from 1965 through November 2011 using a search strategy derived from the following PICO formulation: Patients-patients (18+ years) suspected of AAA. Intervention-bedside ED US to detect AAA. Comparator-reference standard for diagnosing an AAA was a computed tomography (CT), magnetic resonance imaging (MRI), aortography, official US performed by radiology, ED US reviewed by radiology, exploratory laparotomy, or autopsy results. AAA was defined as ≥ 3 cm dilation of the aorta. Outcome-operating characteristics (sensitivity, specificity, and likelihood ratios [LR]) of ED abdominal US. The papers were analyzed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS) guidelines. RESULTS The initial search strategy identified 1,238 articles; application of inclusion/exclusion criteria resulted in seven studies with 655 patients. The weighted average prevalence of AAA in symptomatic patients over the age of 50 years is 23%. On history, 50% of AAA patients will lack the classic triad of hypotension, back pain, and pulsatile abdominal mass. The sensitivity of abdominal palpation for AAA increases as the diameter of the AAA increases. The pooled operating characteristics of ED US for the detection of AAA were sensitivity 99% (95% confidence interval [CI] = 96% to 100%) and specificity 98% (95% CI = 97% to 99%). CONCLUSIONS Seven high-quality studies of the operating characteristics of ED bedside US in diagnosing AAA were identified. All showed excellent diagnostic performance for emergency bedside US to detect the presence of AAA in symptomatic patients.

The utility of shock index in differentiating major from minor injury.

Objective The importance of early recognition of hemorrhagic shock and its effects on outcome have long been recognized. Traditional vital signs are relatively insensitive as early diagnostic markers of hemorrhage. The shock index (SI); heart rate (HR) divided by systolic blood pressure (SBP), has been suggested as such a marker. We tested the diagnostic utility of the SI in differentiating major from minor injury in trauma patients. Methods Retrospective study of a prospectively collected observational cohort at a level I trauma center. Demographics, injury mechanism, HR, SBP, base deficit and lactate were recorded and Injury Severity Score were calculated. Major injury was defined as either a change in hematocrit greater than 10 or blood transfusion requirement during initial 24 h, or Injury Severity Score greater than15. Results One thousand four hundred and thirty-five trauma patients were enrolled, average age 35.2±16.9 years. Two hundred and forty-two were classified as major injury. The area under the receiver operator characteristic curves for SI [0.63 95% confidence interval (CI) 0.59–0.67] was significantly less than that for base deficit (0.72, 95% CI: 0.69–0.76) or lactate (0.69, 95% CI: 0.65–0.73). The diagnostic performance of SI was slightly better than HR (0.58) but not SBP (0.61). To reach sensitivity of 90%, the SI must be 0.5, well in the range of a normal SBP and HR. Conclusion The SI can be a valuable tool, raising suspicion when it is abnormal even when other parameters are not, but is far too insensitive for use as a screening device to rule out disease. A normal SI should not lower the suspicion of major injury.

Does Ethanol Explain the Acidosis Commonly Seen in Ethanol-Intoxicated Patients?

Objective. Emergency physicians frequently treat ethanol-intoxicated trauma patients. In patients with apparently minor injuries, the presence of metabolic acidosis is often attributed to serum ethanol. We tested whether there is justification for the bias that ethanol reliably explains the acidosis commonly seen in alcohol-intoxicated patients. Methods. Prospective, observational. Inclusion criteria: Ethanol-intoxicated patients admitted to the emergency department (ED) following significant trauma mechanisms, in whom diagnostic evaluation revealed only minor injury. Exclusion criteria: Major trauma (blood transfusions, drop in Hct > 10 points over 24 h, or Injury Severity Score [ISS] > 5) or positive urine toxicology screen. Definitions: Ethanol Intoxication: (Blood Alcohol Level (BAL) ≥ 80 mg/dl), Acidosis: BD ≤ − 3.0 mMol/L; Lactic Acidosis (LAC > 2.2 mMol/L). Data were reported as mean ± SD. Data were compared by t-tests or Fishers exact test as appropriate (α = 0.05, 2 tails) and correlations by Pearson correlation coefficient. Results. 192 patients were studied (84% male) with a mean age of 31.7 ± 15.6 years. Acidosis was observed in 19.3% (CI 95%, 14.5% to 25.0%) of all study patients. We observed significant (p < 0.001) difference in prevalence of acidosis in ethanol intoxicated (42%) compared to nonintoxicated (1%) patients. Comparing the two study groups, patients with ethanol intoxication had lower BD ( − 2.24 ± 2.74 vs. − 0.05 ± 2.35, p < 0.001) and higher LAC (2.69 ± 1.48 vs. 2.00 ± 1.78, p = 0.02). However, ethanol levels did not correlate significantly with BD (p = 0.50) or LAC (p = 0.14). Conclusion. Ethanol intoxication is associated with acidosis, which does not correlate with BD or LAC. The complexity of pathogenesis of acidosis in ethanol intoxication justifies further diagnostic evaluation of these patients in order to rule out other causes of acidosis.

Does the early administration of beta-blockers improve the in-hospital mortality rate of patients admitted with acute coronary syndrome?

OBJECTIVES Beta-blockade is currently recommended in the early management of patients with acute coronary syndromes (ACS). This was a systematic review of the medical literature to determine if early beta-blockade improves the outcome of patients with ACS. METHODS The authors searched the PubMed and EMBASE databases for randomized controlled trials from 1965 through May 2009 using a search strategy derived from the following PICO formulation of our clinical question: Patients included adults (18+ years) with an acute or suspected myocardial infarction (MI) within 24 hours of onset of chest pain. Intervention included intravenous or oral beta-blockers administered within 8 hours of presentation. The comparator included standard medical therapy with or without placebo versus early beta-blocker administration. The outcome was the risk of in-hospital death in the intervention groups versus the comparator groups. The methodologic quality of the studies was assessed. Qualitative methods were used to summarize the study results. In-hospital mortality rates were compared using a forest plot of relative risk (RR; 95% confidence interval [CI]) between beta-blockers and controls. Statistical analysis was done with Review Manager V5.0. RESULTS Eighteen articles (total N = 72,249) met the inclusion/exclusion criteria. For in-hospital mortality, RR = 0.95 (95% CI, 0.90-1.01). In the largest of these studies (n = 45,852), a significantly higher rate (p < 0.0001) of cardiogenic shock was observed in the beta-blocker (5.0%) versus control group (3.9%). CONCLUSIONS This systematic review failed to demonstrate a convincing in-hospital mortality benefit for using beta-blockers early in the course of patients with an acute or suspected MI.

Trauma system development in low- and middle-income countries: a review

BACKGROUND Trauma systems in resource-rich countries have decreased mortality for trauma patients through centralizing resources and standardizing treatment. Rapid industrialization and urbanization have increased the demand for formalized emergency medical services and trauma services (EMS and TS) in low- and middle-income countries (LMICs). This systematic review examines initiatives to develop EMS and TS systems in LMICs to inform the development of comprehensive prehospital care systems in resource-poor settings. MATERIALS AND METHODS EMS and TS system development publications were identified using MEDLINE, PubMed, and Scopus databases. Articles addressing subspecialty skill sets, public policy, or physicians were excluded. Two independent reviewers assessed titles, abstracts, and full texts in a hierarchical manner. RESULTS A total of 12 publications met inclusion criteria, and 10 unique LMIC EMS and TS programs were identified. Common initiatives included the integration of existing EMS and TS services and provision of standardized training and formalized certification processes for prehospital care providers, as well as the construction of a conceptual framework for system development through the public health model. CONCLUSIONS There is no single model of EMS and TS systems, and successful programs are heterogeneous across regions. Successful EMS and TS systems share common characteristics. A predevelopment needs assessment is critical in identifying existing EMS and TS resources as a foundation for further development. Implementation requires coordination of preexisting resources with cost-effective initiatives that involve local stakeholders. High-impact priority areas are identified to focus improvements. Financial stresses and mismatching of resources in LMICs are common and are more commonly encountered when implementing a high-income model EMS and TS in an LMIC. Preimplementation and postimplementation evaluations can determine the efficacy of initiatives to strengthen EMS and TS systems.

Increasing ventilator surge capacity in disasters: ventilation of four adult-human-sized sheep on a single ventilator with a modified circuit.

OBJECTIVE Recent manmade and natural disasters have focused attention on the need to provide care to large groups of patients. Clinicians, ethicists, and public health officials have been particularly concerned about mechanical ventilator surge capacity and have suggested stock-piling ventilators, rationing, and providing manual ventilation. These possible solutions are complex and variously limited by legal, monetary, physical, and human capital restraints. We conducted a study to determine if a single mechanical ventilator can adequately ventilate four adult-human-sized sheep for 12h. METHODS We utilized a four-limbed ventilator circuit connected in parallel. Four 70-kg sheep were intubated, sedated, administered neuromuscular blockade and placed on a single ventilator for 12h. The initial ventilator settings were: synchronized intermittent mandatory ventilation with 100% oxygen at 16 breaths/min and tidal volume of 6 ml/kg combined sheep weight. Arterial blood gas, heart rate, and mean arterial pressure measurements were obtained from all four sheep at time zero and at pre-determined times over the course of 12h. RESULTS The ventilator and modified circuit successfully oxygenated and ventilated the four sheep for 12h. All sheep remained hemodynamically stable. CONCLUSION It is possible to ventilate four adult-human-sized sheep on a single ventilator for at least 12h. This technique has the potential to improve disaster preparedness by expanding local ventilator surge capacity until emergency supplies can be delivered from central stockpiles. Further research should be conducted on ventilating individuals with different lung compliances and on potential microbial cross-contamination.

Laryngoscopy force, visualization, and intubation failure in acute trauma: should we modify the practice of manual in-line stabilization?

CERVICAL spine stabilization during transport and general care reduced secondary neurologic injury from 10– 25% to 1–3%. This experience led airway managers to adopt manual in-line stabilization (MILS) during direct laryngoscopy (DL). Although MILS is intuitively appealing, there is, as Santoni et al. state in this issue of ANESTHESIOLOGY, “no objective evidence of benefit.” Substantial ethical and logistical hurdles stand in the way of a randomized controlled trial. The data presented by Santoni et al. combined with previously performed research suggest that no benefit would be found, even if a randomized controlled trial were performed. In contrast to transport and general care, DL mechanically displaces structures adjoining the cervical spine, which transfers force to the vertebrae. By fitting a size 3 Macintosh blade with miniature pressure transducers and employing a randomized crossover design, Santoni et al. demonstrate that MILS doubles the force that must be applied during intubation. That doubling of laryngoscopy force may be harmful is, like MILS, intuitively appealing. In fact, the cadaver study conducted by Lennarson et al. showed that application of MILS significantly increased subluxation at the site of complete ligamentous disruption, even though the intubators in that study obtained only “limited visualization . . . intended to produce the least cervical movement possible.” Santoni et al. provide a plausible explanation for the Lennarson group’s findings – the laryngoscopists in both studies needed to apply more pressure to overcome the effects of MILS, and the increased pressure caused greater subluxation in the cadaveric injury model. In practice, MILS probably has greater effects on the injury site than Lennarson’s group reported. Clinicians working under the trying circumstances of an acute trauma intubation are more likely than study participants to focus on successfully passing the tube and are less likely to focus on limiting the force they apply to the laryngoscope. Even with the important new data from Santoni et al., we doubt that clinicians will be eager to abandon or even modify MILS. During the past few decades, there have been few, if any, reliable reports of intubation causing secondary spinal cord injury, and MILS has been the standard of care. This record will not be easily dismissed because many clinicians share our concern that patients will be injured by any change in practice. The dilemma is ironic because the work of Santoni et al. and Lennarson et al. suggest that this fortunate history may be despite, and not because of, MILS. The paper by Santoni et al. raises another concern. As Nolan and Wilson and others have demonstrated, MILS degrades DL view. Santoni et al. observed this in six of nine patients who were successfully randomized. Although not designed to do so, the study illustrates how harmful view degradation can be. With MILS, anesthesiologists having an average of 19 yr experience could not intubate 3 of 10 fasted, stable patients screened to exclude predictors of difficult intubation. The first of these patients was not included in the study because the laryngoscopist obtained a grade four view with the modified Macintosh 3 blade and felt it necessary to use a size 4. One patient was esophageally intubated, and the third sustained a dental injury. These three incidents in this small study are remarkable because much trauma airway management is performed by clinicians with far less experience than the participating anesthesiologists. In addition, these intubation attempts were made under well-controlled circumstances, in contrast to many acute trauma intubations. Although trauma airway studies in academic centers demonstrate high success rates by anesthesia and emergency physicians, this work does not directly support MILS. These studies included penetrating trauma; although clinicians almost certainly used MILS in the blunt trauma cases, it is impossible to know how rigorously they applied the technique. One of these studies reported that 35% of the patients experienced complications, including hypoxia in 17%. The MILS-associated intubation failures observed by Santoni et al. probably explain a significant percentage of the hypoxic events. This is troubling because patients intubated with MILS are far more likely to have traumatic brain injury than unstable C-spine fractures, and SaO2 ! 90% predicts poor neurologic outcome. Technically, there are some important limitations to the work by Santoni et al. Because the group measured pressure directed against the anterior surface of a Macintosh blade, the intubators could not use external posteriorly directed pressure. Posterior pressure may improve view and increase intubation success in some patients, so this restriction could have resulted in the application This Editorial View accompanies the following article: Santoni BG, Hindman BJ, Puttlitz CM, Weeks JB, Johnson N, Maktabi MA, Todd MM: Manual in-line stabilization increases pressures applied by the laryngoscope blade during direct laryngoscopy and orotracheal intubation. ANESTHESIOLOGY 2008; 109:24–31. !

Routine testing in patients with asymptomatic elevated blood pressure in the ED

STUDY OBJECTIVE There are no clear recommendations for the diagnostic evaluation of patients who present to the emergency department (ED) with asymptomatic elevated blood pressure. In patients presenting with asymptomatic elevated blood pressure in the ED, we measured the prevalence of abnormalities on a basic metabolic profile (BMP) that led to hospital admission as well as the prevalence of diminished renal function. METHODS This is a cross-sectional study at 2 urban teaching EDs with a largely African American population. Adult patients (> or = 18 years) with a triage diastolic blood pressure (BP) 100 mm Hg or higher and without symptoms suggestive of acute end-organ damage were enrolled. All patients had a BMP sent. The primary outcome measured was abnormalities on the BMP that led to hospital admission. The secondary outcome measured was the prevalence of diminished renal function (glomerular filtration rate <60 mL min(-1) 1.73 m(-2)). RESULTS One hundred sixty-seven patients with asymptomatic elevated BP were studied. Twelve (7.2%; 95% confidence interval, 3%-11%) patients were admitted due to abnormal results on the BMP. Twenty-seven (16.2%; 95% confidence interval, 11%-21%) patients met the secondary outcome measure of diminished renal function (glomerular filtration rate <60 mL min(-1) 1.73 m(-2)). CONCLUSION In a homogenous African American population presenting to the ED with asymptomatic elevated BP, there is a relatively high prevalence of abnormalities on the BMP that led to hospital admission. We suggest routine testing of a serum creatinine should be strongly considered in a largely African American patient population with asymptomatic elevated BP in the ED.