1208 Abstracts

for whom transfusions may or may not be indicated. The age ofpRBCs should be taken into account before transfusion.

, USEFULNESS OF HIGH-SENSITIVITY TROPONINT FORTHE EVALUATIONOF PATIENTSWITH ACUTECHEST PAIN AND NO OR MINIMAL MYOCARDIALDAMAGE. Sanchis J, Bardaji A, Bosch X, et al. Am Heart J2012;164-2:194–200.

High-sensitivity troponin has been shown to be an effectivediagnostic tool in assessment of patients with acute myocardialinfarction (MI). This study aimed to evaluate the role of high-sensitivity troponin in the diagnosis of acute coronary syndrome(ACS). Patients presenting to the Emergency Department withacute chest pain and two normal serial troponins were includedin this prospective multicenter study. A total of 446 patientswere included; mean age was 60 years old. Two blood samplesfrom each participant were measured for high-sensitivity tropo-nin T. The primary end point was diagnosis of acute coronarysyndrome as measured by angiography, stress test, or cardiacevent at a 30-day follow-up. Eighty-four patients were diag-nosed with acute coronary syndrome, 62 of whom underwentin-hospital revascularization or were found to have a cardiacevent at 30-day follow-up (composite end point). The studyshowed that a maximum high-sensitivity troponin > 3 ng/L ex-hibited a high sensitivity for detection of ACS and the compositeend point (87% and 92%) and a negative predictive value (93%and 97%). A value $ 14 ng/L was found to be highly specific(90% and 89%), with positive predictive values of 40% and33%. A high-sensitivity troponin level of # 3 ng/L provideda high negative predictive value for ACS. One limitation tothe study was the strict exclusion criteria, such as patientswith known coronary artery disease, non-ST elevation acuteMI, or those unable to undergo an exercise stress test. Overall,the utility of high-sensitivity troponin, when added to electro-cardiogram and clinical history, was found to be marginal.

[Mariah Bellinger, MD

Denver Health Medical Center, Denver, CO]

Comments: Although the study’s objectives were intriguing,it seems that many patients who present to the Emergency De-partment with chest pain were excluded from the study. The util-ity of high-sensitivity troponin T seems to be low whencompared to electrocardiogram, history, and clinical gestalt.

, THE NATURAL COURSE OF UNRUPTURED CE-REBRAL ANEURYSMS IN A JAPANESE COHORT.Morita A, Kirino T, Hashi K, et al., UCAS Japan Investigators.N Engl J Med 2012;366:2474–82.

This study from Japan identified 6697 newly diagnosed un-ruptured aneurysms in 5720 patients, 20 years of age or older(mean age 62.5 years; 68%women), from January 2001 throughApril 2004. Only saccular aneurysms that were 3 mm or greaterin the largest dimension, and patients presenting with no morethan a slight disability were included in the study. Previous stud-ies have shown that aneurysms smaller than 7 mm in the largestdimension rarely rupture, and that aneurysms in the posteriorcirculation have higher tendency to rupture when compared toanterior circulation. This prospective cohort study sought to elu-

cidate the natural course of unruptured cerebral aneurysms inthe Japanese population and to identify specific independentrisk factors associated with rupture. Follow-up data were ob-tained at 3, 12, and 36 months after initial visit and at 5 and 8years if data were available. Data collection ended after aneu-rysm rupture or when the patient died. If any surgical interven-tion took place, data were still collected but no longer includedin the risk analysis. The patients studied had a total of 111 aneu-rysm ruptures, which resulted in 0.95% annual risk of rupture(95% confidence interval [CI] 0.79–1.15). When comparedwith 3- to 4-mm-size aneurysms, larger aneurysms were associ-ated with higher rates of rupture. The hazard ratios (95% CI)were as follows: 5–6 mm, 1.13 (0.58–2.22); 7–9 mm, 3.35(1.87–6); 10–24 mm, 9.09 (5.225–15.74); and > 25 mm, 76.26(32.76–177.54). Aneurysms in the posterior and anterior com-municating arteries were more likely to rupture when comparedto the middle cerebral arteries (hazard ratios and 95% CI 1.90[1.12–3.21] and 2.02 [1.13–3.58], respectively). Aneurysmswith an irregular wall, called a daughter sac, were also morelikely to rupture when compared to smooth wall aneurysms(hazard ratio 1.63 [95% CI 1.08–2.48]). The authors concludedthat size, location, and shape of the aneurysm influence the nat-ural course of unruptured aneurysms. Factors that were foundnot to significantly influence the risk of rupture included: thepresence of another aneurysm causing subarachnoid hemor-rhage (SAH), former or current smoker, a family history ofSAH, hypertension, and the presence of multiple aneurysms.Limitations of the study included the factor that the data fromaneurysms treated surgically were not included in analysis,which led to a selection bias, and the fact that the study only in-cluded Japanese patients.

[Sabrina Adams, MD

Denver Health Medical Center, Denver, CO]

Comments: This study provides us with a better understand-ing of the risk of rupture of cerebral aneurysms, and treatmentchoice can be guided after obtaining the size, location, andshape of saccular aneurysms. However, caution must be usedwhen extrapolating the overall risk of rupture to our population.-

, FACTORS COMPLICATING INTERPRETATION OFCAPNOGRAPHY DURING ADVANCED LIFE SUPPORTIN CARDIAC ARREST—A CLINICAL RETROSPEC-TIVE STUDY IN 575 PATIENTS. Heradstveit BE, Sunde K,Sunde GA, Wentzel-Larsen T, Heltne JK. Resuscitation2012;83:813–8.

This study from Norway evaluated the levels of end-tidalcarbon dioxide (ETCO2) capnography in patients with out-of-hospital cardiac arrest (OHCA), and its interpretation limita-tions based on initial heart rhythm, cause of the arrest, presenceof bystander cardiopulmonary resuscitation (CPR), and time de-pendency on a retrospective study. Capnography data wereavailable for 575 non-traumatic OHCA patients that were intu-bated and treated by the Helicopter EmergencyMedical Serviceat Haukelend University Hospital over a period of 6 years. Cap-nography data were recorded manually by the anesthesiologistafter 1 min of normal ventilation and included the minimal,

The Journal of Emergency Medicine 1209

maximal, and average ETCO2 number for the initial 15 min dur-ing advance life support (ALS) or until return of spontaneouscirculation (ROSC). Capnography was significantly higher onpatients that regained ROSC when compared to those withoutit for any initial rhythm and cause of the arrest (p < 0.001).ETCO2 levels were also significantly higher with respiratorycause of arrest when compared to primary cardiac causes. Thelowest ETCO2 were observed when cardiac arrest resultedfrom pulmonary embolism. Another factor found to influenceETCO2 included initiation of CPR by bystander and the timeof recording after the arrest, the earlier the initiation of CPRby bystander and the earlier the monitoring after arrest, thehigher the ETCO2 levels. The authors concluded that severalfactors complicate the interpretation of ETCO2 during ALS,and no clear cut-off value can be determined whether ROSCwas achieved or not. Previous clinical studies have shown thatETCO2 > 2.4 kPa after 20 min has been shown to predictROSC, and values < 1.3 kPa have been associated with noROSC. The authors warned of the importance of not using strictcut-off values that could mistakenly lead to premature treatmentwithdrawal. Major limitations included the fact that anesthesiol-ogists recorded numbers manually, patients were manually ven-tilated, and epinephrine use was not recorded.

[Sabrina Adams, MD

Denver Health Medical Center, Denver, CO]

Comments: This study raised an important point when itcomes to the interpretation of ETCO2 values during ALS be-cause so many confounding factors play a role. Quality of chestcompressions directly impact ETCO2 numbers and should stillbe used to encourage rescuers to maximize their quality ofCPR.

, EFFECTS OF FLUID RESUSCITATION WITH SYN-THETIC COLLOIDS OR CRYSTALLOIDS ALONE ONSHOCK REVERSAL, FLUID BALANCE, AND PATIENTOUTCOMES IN PATIENTS WITH SEVERE SEPSIS: APROSPECTIVE SEQUENTIAL ANALYSIS. Bayer O,Reinhart K, Khol M, et al. Crit Care Med 2012;40:2543–51.

The best choice of asanguineous fluid to use during severesepsis is still controversial. Some data suggest that the use ofcolloids can improve cardiac performance and were associatedwith lower resuscitation volumewhen compared to crystalloids.This prospective study from Germany assessed shock reversaland required fluid volumes in 1046 patients that presented tothe surgical intensive care unit (ICU) with septic shock overa period of 6 years. Three fluid therapies were used, including6% hydroxyethyl starch (HES), n = 360; 4% gelatin, n = 352;and crystalloids alone, n = 334. Time to shock reversal was de-fined as serum lactate < 2.2 mmol/L or discontinuation of vaso-pressors, and considered the main outcome for the study.Hemodynamic goals included mean arterial blood pressure> 70 mm Hg, central venous pressure > 8, and central venousoxygen saturation > 70%. And safety outcomes included acutekidney injury (AKI) and new need for renal replacement therapy(RRT). There was no significant difference among the threefluid therapies regarding time to shock reversal. More fluidswere needed over the first 4 days to achieve hemodynamic goals

in the crystalloid-alone group (fluid ratios 1.4:1 [crystalloid toHES] and 1.1:1 [crystalloid to gelatin]). However, after day 5,total fluid balance was more negative in the crystalloid groupwhen compared to the other groups. HES and gelatin fluidsuse were independent risk factors for AKI (odds ratio, 95% con-fidence interval: 2.55, 1.76–3.69 and 1.85, 1.31–2.62, respec-tively). It was also noted that patients who received syntheticcolloids received more allogenic blood products when com-pared to crystalloids. Severity scores, hospital length of stay,and ICU or hospital mortality were similar among all groups.Patients in both colloid groups, significantly, spent longer pe-riods of time on the ventilator and had longer ICU lengths ofstay. The authors concluded that shock reversal does not occurfaster when using colloids and there is no fluid saving when us-ing colloids vs. crystalloids alone. The study also showed thatcolloids are not completely safe and lead to a higher numberof renal impairment and higher RRT use. Limitations includeits single-center design and randomization.

[Sabrina Adams, MD

Denver Health Medical Center, Denver, CO]

Comments: New HES clinical trials are currently ongoing incritically ill or septic patients. This study showed important datawhen it comes to fluid selection. Given that crystalloids havesignificantly lower cost and are associated with less complica-tions, at least until more research is done, it should be the fluidof choice when resuscitating septic patients.

, INCREMENTAL PROGNOSTIC VALUE OF DIFFER-ENT COMPONENTS OF CORONARY ATHEROSCLE-ROTIC PLAQUE AT CARDIAC CT ANGIOGRAPHYBEYOND CORONARY CALCIFICATION IN PATIENTSWITH ACUTE CHEST PAIN. Nance JW Jr, Schlett CL,Schoepf UJ, et al. Radiology 2012;264:679–90.

In this single-centered, retrospective cohort study of 458low-to-intermediate-risk patients presenting with acute onsetchest pain and without acute coronary syndrome or non-cardiacetiology of their symptoms on initial work-up, the authors inves-tigated the value of coronary artery calcium (CAC) score andcardiac computed tomography (CT) angiography in predictingthe risk for major adverse coronary events (MACE). Of the458 patients included in the analysis, 70 (15%) had a MACEduring the 24-month follow-up period. Here MACEwas definedby cardiac death (due to myocardial infarction, heart failure, ordysrhythmia), non-fatal myocardial infarction, unstable angina,or need for revascularization procedure (coronary artery bypassgraft or percutaneous coronary intervention). In patients withoutatherosclerotic plaque seen on CT angiography, there were zeroadverse events. Among patients with CAC scores of zero, 5%experienced adverse cardiac events. Among patients withoutcoronary artery stenosis on CT angiography, 10% experienceda MACE. One hundred percent of patients with MACE had ath-erosclerotic plaques by CT angiography, whereas 59% of pa-tients without MACE had atherosclerotic plaques. Of patientswith MACE and atherosclerotic plaque, 74% demonstratedmixed calcified and non-calcified disease, whereas exclusivelycalcified and exclusively non-calcified plaques represent 9%and 17% of atherosclerotic disease associated with MACE.