Tae Yun Kim

Acute Appendicitis in Young Adults: Low- versus Standard-Radiation-Dose Contrast-enhanced Abdominal CT for Diagnosis

PURPOSE To compare low and standard radiation doses in intravenous contrast material-enhanced abdominal computed tomography (CT) for the diagnosis of acute appendicitis in young adults. MATERIALS AND METHODS The institutional review board approved this retrospective study and waived informed consent. The study included 257 patients (age range, 15-40 years) who underwent CT for suspected appendicitis performed by using a low radiation dose (n = 125) or a standard radiation dose (n = 132). Receiver operating characteristic (ROC) analysis, Fisher exact tests, and Mann-Whitney U tests were used to compare the diagnosis of appendicitis and diagnostic confidence as recorded in prospective CT reports between the two groups. RESULTS For 55 low-radiation-dose (median dose-length product, 122 mGy · cm) and 44 standard-dose (median dose-length product, 544 mGy · cm) examinations, one of two abdominal radiologists made primary reports that served as final reports. For the remaining examinations, on-call radiologists with differing levels of experience issued preliminary reports and the two abdominal radiologists then provided final reports. In the primary reports, the low- and standard-dose CT groups did not significantly differ in area under the ROC curve (0.96 vs 0.97, P = .76), sensitivity (90% [38 of 42] vs 89% [47 of 53], P > .99), or specificity (92% [76 of 83] vs 94% [74 of 79], P = .74) in the diagnosis of appendicitis. There was also no significant difference between the two groups in the confidence level when diagnosing (P = .71) or excluding (P = .20) appendicitis in the primary reports. Similar results were observed for the final reports. The two dose groups also did not significantly differ in terms of appendiceal visualization, diagnosis of appendiceal perforation, or sensitivity for alternative diagnoses. CONCLUSION Low-dose CT may have comparable diagnostic performance to standard-dose CT for the diagnosis of appendicitis in young adults.

Red blood cell distribution width as an independent predictor of all-cause mortality in out of hospital cardiac arrest

OBJECTIVE Post-resuscitation period is characterized by high early mortality due to post-cardiac arrest syndrome. Recent studies found that elevated red cell distribution width (RDW) is a strong predictor of mortality in critically ill patients. We investigated the prognostic significance of RDW in out-of-hospital cardiac arrest (OHCA) victims. METHODS Analysis of emergency department OHCA registry extending from January 2007 to December 2010 was conducted. Patients with ROSC were assessed for Utstein predictors including sex, age, arrest location, presence of witness, bystander cardiopulmonary resuscitation, response time, initial rhythm and cause of arrest. RDW, hematocrit, white blood cell and platelet counts, blood urea nitrogen (BUN), creatinine and albumin were also obtained. Outcome variable was survival duration within 30 days. RDW was categorized in quartiles as <13.2%, 13.2% to 14.0%, 14.1% to 15.4% and >15.4%. Hazard ratios (HRs) were estimated using Cox-proportional hazard models in both univariate and multivariate analysis. All prognostic variables with their p value<0.1 in univariate analysis were used in multivariate analysis for adjustment. RESULTS Among 409 OHCA patients, 219 patients had ROSC. Highest RDW quartile (RDW>15.4%), female sex, older age, non-shockable initial rhythm, increased BUN and creatinine and decreased albumin, hematocrit and platelet count were associated with increased mortality in univariate analysis. In multivariate analysis, the highest RDW quartile was independently associated with all-cause mortality (HR=1.95; 95% CI 1.05-3.60; p=0.034) during 30-day post-resuscitation period. Other significant variables were age, initial rhythm and serum albumin. CONCLUSIONS Initial RDW is an independent predictor of all-cause mortality in post-resuscitation patients.

Prognostic value of N-terminal pro-brain natriuretic peptide in hospitalised patients with community-acquired pneumonia

Background The prognostic role of N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with community-acquired pneumonia (CAP) has not been evaluated. The aim of the present study was to investigate whether NT-proBNP level could predict mortality in hospitalised CAP patients. Methods We performed a structured medical record review of all hospitalised CAP patients from May 2003 to October 2006, and classified patients into the 30-day survival and non-survival group. Data included demographic and clinical characteristics, and laboratory findings including NT-proBNP levels. The APACHE II scores, PSI (pneumonia severity index) and CURB65 (confusion, urea, respiratory rate, blood pressure and aged 65 or more) scores were calculated. Comparisons between survivors and non-survivors were made with χ2, non-parametric tests and logistic regression and ROC analysis were used to compare the ability of NT-proBNP (adjusted for age, heart failure and creatinine), APACHE II, PSI and CURB65 to predict mortality. Results Of 502 patients, 61 (12.2%) died within 30 days. NT-proBNP levels were measured in 167 patients and were significantly higher in non-survivors compared to survivors (median 841.7 (IQR 267.1–3137.3) pg/ml vs 3658.0 (1863.0–7025.0) pg/ml, p=0.019). NT-proBNP was an independent predictor of mortality (adjusted OR 1.53; 95% CI 1.16 to 2.02, p=0.002). The AUC for NT-proBNP was 0.712 (95% CI, 0.613 to 0.812), which was comparable to those of PSI (0.749, p=0.531) and CURB65 (0.698, p=0.693), but inferior to that of APACHE II (0.831, p=0.037). Adding NT-proBNP to APACHE II, PSI and CURB65 did not significantly increase the AUCs, respectively. Conclusions NT-proBNP level is an independent predictor of mortality in hospitalised CAP patients. The performance of NT-proBNP level is comparable to those of PSI and CURB65 in predicting mortality.

A randomized comparison of nitrous oxide versus intravenous ketamine for laceration repair in children.

Objective Ketamine is used intramuscularly or intravenously as a sedative when repairing the skin lacerations of children in many emergency departments (EDs). Nitrous oxide (N2O) has the advantages of being a sedative agent that does not require a painful injection and that offers shallower levels of sedation and a rapid recovery of mental state. We evaluated the clinical usefulness of N2O compared with intravenous ketamine when used for the repair of lacerations in children in the ED. Methods From January to December 2009, we performed a prospective, randomized study at a single academic ED enrolling pediatric patients aged 3 to 10 years who needed primary repair of a laceration wound. The primary outcome was recovery time, which was defined as the time from completion of procedure to recovery of mental state. Other outcomes were sedation depth, pain scale, adverse effects, and satisfaction with sedation. Results There were 32 children who were randomly assigned. Recovery times were shorter in the N2O group compared with those in the ketamine group (median [interquartile range (IQR)], 0.0 minutes, [0.0–4.0 minutes] vs 21.5 minutes [12.5–37.5 minutes], P < 0.05). Sedation levels were deeper in the ketamine group than in the N2O group, but pain scales were comparable between groups. No difference was observed in the satisfaction scores by physicians, parents, or nurses. Conclusions Nitrous oxide inhalation was preferable to injectable ketamine for pediatric patients because it is safe, allows for a faster recovery, maintains sufficient sedation time, and does not induce unnecessarily deep sedation.

A simple model to predict bacteremia in women with acute pyelonephritis.

OBJECTIVES To construct a simple model to predict bacteremia in women with uncomplicated acute pyelonephritis (APN) for the judicious use of blood cultures. METHODS A prospective database including 735 women with uncomplicated APN at an academic urban emergency department was analyzed retrospectively. Independent risk factors were determined using multivariate logistic regression in two-thirds of patients. Cutoff values representing 10% and 30% of risk were selected for the stratification. This model was internally and externally validated using a remaining one-thirds of patients and 169 independent patients, respectively. RESULTS Independent risk factors were as follows: age ≥65 years (odds ratio [OR]=5.18, 4 points), vomiting (OR=2.40, 2 points), heart rate >110 beats/min (OR=2.35, 2 points), segmented neutrophils >90% (OR=3.17, 3 points), and urine WBC ≥50/HPF (OR=4.27, 4 points). Patients were stratified as low (points <4), intermediate (points, 4-6), or high risk (7≤ points). The areas under receiver operating characteristics curves were 0.707 and 0.792 in internal and external validation cohorts, respectively. The model stratified internal and external validation cohort into low (8.5% and 5.7%), intermediate (16.5% and 14.8%), and high risk of bacteremia (42.0% and 56.4%). CONCLUSIONS This model provides a useful tool to predict the risk of bacteremia, which can be helpful to decide whether to perform blood cultures and whether to admit the patient for the intravenous antibiotics in women with uncomplicated APN.

The accuracy of emergency medicine and surgical residents in the diagnosis of acute appendicitis

OBJECTIVE This study was conducted to compare the diagnostic accuracy for acute appendicitis between emergency medicine residents (EMRs) and surgical residents (SRs). METHODS We conducted a prospective cohort study of adult patients with right lower quadrant pain. Each patient was evaluated by an EMR and an SR, and physicians predicted the probability of appendicitis into 4 groups from highest (group 1) to lowest (group 4). The diagnostic accuracies of EMR and SR for the diagnosis of appendicitis were compared by constructing receiver operating characteristics curves. In each case, an Alvarado score was calculated and a computed tomography (CT) scan of the abdomen and pelvis was performed, and their diagnostic accuracies were also compared with the predicted probabilities. RESULTS Of a total 191 patients, 120 underwent surgery, and the negative appendectomy rate was 6.8%. There was a significant correlation between the predicted probabilities of EMR and SR. The areas under the curve for EMR and SR were 0.698 and 0.657, which were not statistically different. The areas under the curve of the Alvarado score and the CT were 0.735 and 0.978, respectively. The diagnostic accuracy of the CT scan was significantly higher than those of the Alvarado score and the resident-predicted probabilities. CONCLUSION In patients with right lower quadrant abdominal pain who have already been evaluated by EMR, consultation evaluation by SR does not appear to improve clinical diagnostic accuracy, and routine performance of CT before surgical consultation should be considered for these patients.

Risk stratification nomogram for nephropathy after abdominal contrast-enhanced computed tomography

OBJECTIVES Abdominal contrast-enhanced computed tomography (A-CECT) is widely used in emergency departments despite the risk of contrast-induced nephropathy. We attempted to develop a risk stratification nomogram for nephropathy in patients receiving emergency A-CECT. METHODS Seven hundred fifty patients who received emergency A-CECT between August 2003 and January 2007, with available serum creatinine (SCr) measurements before and after A-CECT were included. Nephropathy was defined as either an absolute increase of 0.5 mg/dL or greater (44 μmol/L) or a relative increase of 25% or more in the SCr from baseline. A nomogram was developed based on multivariate logistic regression analysis using clinical variables available before A-CECT. The model was internally validated with a bootstrapping method, and performance was assessed by area under the receiver operating characteristics curve (AUC) and calibration curve. RESULTS Nephropathy was observed in 34 of 750 patients. A nomogram was developed using age (odds ratio, 1.04 per 1-year increment) and baseline SCr (odds ratio, 2.51 per 1-mg/dL increment) as risk factors. Diagnostic accuracy of the model was fair by bias-corrected calibration plot. The AUC of the model was 0.794 (95% confidence interval, 0.734-0.854), and the AUC with bootstrapping samples of 200 repetitions was 0.794 (95% confidence interval, 0.737-0.851). CONCLUSION The risk of nephropathy after emergency A-CECT can be individually predicted by internally validated nomogram using clinical variables available before the procedure.

Effect of speed of rewarming and administration of anti-inflammatory or anti-oxidant agents on acute lung injury in an intestinal ischemia model treated with therapeutic hypothermia

AIM OF THE STUDY Acute lung injury (ALI) develops in various clinical situations and is associated with high morbidity and mortality and therapeutic hypothermia (HT) has been studied to attenuate the ALI. However, the optimal method of rewarming has not been determined. We determined the effect of speed of rewarming and the administration of anti-inflammatory or anti-oxidant agents on ALI in an intestinal ischemia and reperfusion (I/R) model treated with HT. MATERIALS AND METHODS A Sprague-Dawley rat model of intestine ischemia and reperfusion was used. Two parallel animal experiments were conducted. In the survival study, rats (n=5 per group) underwent normothermic intestinal ischemia (60min, 36-38 degrees C) and then randomized into 7 groups with reperfusion: normothermia (NT), HT without rewarming (30-32 degrees C, HT), 2h HT+rewarming for 1h (RW1), 2h HT+rewarming for 2h (RW2), RW1+N-acetyl cysteine (RW-NAC), RW1+ethylpyruvate (RW-EP), and RW1+dexamethasone (RW+Dexa). In the second experiment, we investigated the histological and biochemical effects on the lung 4h after reperfusion (n=8 per group). RESULTS The survival rate was lowest after NT. The HT, RW2, and RW-Dexa groups survived longer than the RW1, RW-NAC, and RW-EP groups. ALI scores were lower in the HT, RW2, and RW-Dexa groups than RW1. Lung malondialdehyde content was also lower in these groups. Interleukin (IL)-6 was significantly higher in the RW1 group. Inducible NO synthase gene expression in lung was lower in the HT, RW2, and RW-Dexa than RW1, and serum NO was lower in the RW2 and RW-Dexa than RW1. CONCLUSION Gradual rewarming and administration of dexamethasone improved survival and attenuated ALI after intestinal I/R injury treated with HT in rats.

Heart-type Fatty Acid Binding Protein as an Adjunct to Cardiac Troponin-I for the Diagnosis of Myocardial Infarction

We hypothesized that when used in combination with cardiac troponins, heart-type fatty acid binding protein (H-FABP) would have greater diagnostic value than conventional markers for the early diagnosis of myocardial infarction (MI). Patients with typical chest pain at a single emergency department were consecutively enrolled. Initial blood samples were drawn for H-FABP, myoglobin, creatine kinase isoenzyme MB (CK-MB), and cardiac troponin-I (cTnI) measurements. MI was defined by serial cTnI measurements. To evaluate the adjunctive role of biochemical markers, we derived and compared logistic regression models predicting MI in terms of their discrimination (area under the receiver operating characteristics curve, AUC) and overall fit (Bayesian information criterion, BIC). Seventy-six of 170 patients were diagnosed as having MI. The AUC of cTnI, H-FABP, myoglobin, and CK-MB were 0.863, 0.827, 0.784, and 0.772, respectively. A logistic regression model using cTnI (P = 0.001) and H-FABP (P < 0.001) had the biggest AUC (0.900) and the best fit determined by BIC. Sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of this model at 30% probability were 81.6%, 80.9%, 4.26, and 0.23, respectively. H-FABP has a better diagnostic value than both myoglobin and CK-MB as an adjunct to cTnI for the early diagnosis of MI.

The Effect of Head Up Cardiopulmonary Resuscitation on Cerebral and Systemic Hemodynamics.

AIM Chest compressions during cardiopulmonary resuscitation (CPR) increase arterial and venous pressures, delivering simultaneous bidirectional high-pressure compression waves to the brain. We hypothesized that this may be detrimental and could be partially overcome by elevation of the head during CPR. MEASUREMENTS Female Yorkshire farm pigs (n=30) were sedated, intubated, anesthetized, and placed on a table able to elevate the head 30° (15cm) (HUP) and the heart 10° (4cm) or remain in the supine (SUP) flat position during CPR. After 8minutes of untreated ventricular fibrillation and 2minutes of SUP CPR, pigs were randomized to HUP or SUP CPR for 20 more minutes. In Group A, pigs were randomized after 2minutes of flat automated conventional (C) CPR to HUP (n=7) or SUP (n=7) C-CPR. In Group B, pigs were randomized after 2minutes of automated active compression decompression (ACD) CPR plus an impedance threshold device (ITD) SUP CPR to either HUP (n=8) or SUP (n=8). RESULTS The primary outcome of the study was difference in CerPP (mmHg) between the HUP and SUP positions within groups. After 22minutes of CPR, CerPP was 6±3mmHg in the HUP versus -5±3 in the SUP (p=0.016) in Group A, and 51±8 versus 20±5 (p=0.006) in Group B. Coronary perfusion pressures after 22minutes were HUP 6±2 vs SUP 3±2 (p=0.283) in Group A and HUP 32±5 vs SUP 19±5, (p=0.074) in Group B. In Group B, 6/8 pigs were resuscitated in both positions. No pigs were resuscitated in Group A. CONCLUSIONS The HUP position in both C-CPR and ACD+ITD CPR significantly improved CerPP. This simple maneuver has the potential to improve neurological outcomes after cardiac arrest.