Chang Hwan Sohn

Correlation between National Influenza Surveillance Data and Google Trends in South Korea

Background In South Korea, there is currently no syndromic surveillance system using internet search data, including Google Flu Trends. The purpose of this study was to investigate the correlation between national influenza surveillance data and Google Trends in South Korea. Methods Our study was based on a publicly available search engine database, Google Trends, using 12 influenza-related queries, from September 9, 2007 to September 8, 2012. National surveillance data were obtained from the Korea Centers for Disease Control and Prevention (KCDC) influenza-like illness (ILI) and virologic surveillance system. Pearsons correlation coefficients were calculated to compare the national surveillance and the Google Trends data for the overall period and for 5 influenza seasons. Results The correlation coefficient between the KCDC ILI and virologic surveillance data was 0.72 (p<0.05). The highest correlation was between the Google Trends query of H1N1 and the ILI data, with a correlation coefficient of 0.53 (p<0.05), for the overall study period. When compared with the KCDC virologic data, the Google Trends query of bird flu had the highest correlation with a correlation coefficient of 0.93 (p<0.05) in the 2010-11 season. The following queries showed a statistically significant correlation coefficient compared with ILI data for three consecutive seasons: Tamiflu (r = 0.59, 0.86, 0.90, p<0.05), new flu (r = 0.64, 0.43, 0.70, p<0.05) and flu (r = 0.68, 0.43, 0.77, p<0.05). Conclusions In our study, we found that the Google Trends for certain queries using the survey on influenza correlated with national surveillance data in South Korea. The results of this study showed that Google Trends in the Korean language can be used as complementary data for influenza surveillance but was insufficient for the use of predictive models, such as Google Flu Trends.

An Increase in Initial Shock Index Is Associated With the Requirement for Massive Transfusion in Emergency Department Patients With Primary Postpartum Hemorrhage

ABSTRACT The aim of this study was to determine whether initial shock index (SI) was independently associated with the requirement for massive transfusion (MT) in emergency department (ED) patients with primary postpartum hemorrhage (PPH). A retrospective cohort study of ED patients with primary PPH was performed at a university-affiliated, tertiary referral center between January 2004 and May 2012. Patients were classified to two groups: MT group (patients who received ≥10 U of packed red blood cells within 24 h of ED admission) and non-MT group (patients who received <10 U). Variables of the two groups were compared using univariate and multivariate analyses. A total of 126 patients were included in this study. Of these patients, 26 (20.6%) were included in MT group and 100 (79.4%) in non-MT group. Patients in MT group had significantly lower blood pressure and higher heart rate compared with patients in non-MT group (P < 0.01). Initial SI was significantly higher in MT group than in non-MT group (1.3 vs 0.8, P < 0.01). In multivariate logistic regression analysis, initial SI and heart rate were the only variables associated with the requirement for MT, with an odds ratio of 9.47 (95% confidence interval, 1.75–51.28; P < 0.01) and 1.06 (95% confidence interval, 1.02–1.09; P < 0.01), respectively. In conclusion, initial SI was independently associated with the requirement for MT in ED patients with primary PPH. Routine calculation of initial SI can help clinicians to identify patients who may benefit from timely and appropriate use of MT to improve clinical outcomes.

Factors associated with the occurrence of cardiac arrest after emergency tracheal intubation in the emergency department.

Objectives Emergency tracheal intubation has achieved high success and low complication rates in the emergency department (ED). The objective of this study was to evaluate the incidence of post-intubation CA and determine the clinical factors associated with this complication. Methods A matched case-control study with a case to control ratio of 1∶3 was conducted at an urban tertiary care center between January 2007 and December 2011. Critically ill adult patients requiring emergency airway management in the ED were included. The primary endpoint was post-intubation CA, defined as CA within 10 minutes after tracheal intubation. Clinical variables were compared between patients with post-intubation CA and patients without CA who were individually matched based on age, sex, and pre-existing comorbidities. Results Of 2,403 patients who underwent emergency tracheal intubation, 41 patients (1.7%) had a post-intubation CA within 10 minutes of the procedure. The most common initial rhythm was pulseless electrical activity (78.1%). Patients experiencing CA had higher in-hospital mortality than patients without CA (61.0% vs. 30.1%; p<0.001). Systolic hypotension prior to intubation, defined as a systolic blood pressure ≤90 mmHg, was independently associated with post-intubation CA (OR, 3.67 [95% CI, 1.58–8.55], p = 0.01). Conclusion Early post-intubation CA occurred with an approximate 2% frequency in the ED. Systolic hypotension before intubation is associated with this complication, which has potentially significant implications for clinicians at the time of intubation.

Long-term neurological outcomes in patients after out-of-hospital cardiac arrest.

AIM The main treatment goal in survivors of out-of-hospital cardiac arrest (OHCA) is a favorable neurologic outcome. Little is known, however, about long-term trends of neurologic status in OHCA survivors. This study was designed to assess the rates of long-term neurologic recovery and survival according to neurologic status at one month. METHODS This retrospective observational study assessed all adult OHCA survivors (≥18 years) admitted to a tertiary hospital in an urban area who achieved return of spontaneous circulation (ROSC) between July 2005 and August 2013. Neurologic outcomes were measured by Cerebral Performance Category (CPC) score and patients were categorized according to CPC score at 1 month. Their neurologic status was re-evaluated 6, 12, and 24 months after cardiac arrest. RESULTS Of 778 OHCA cases, 282 patients (36.2%) were admitted to our hospital, and 279 were included in this study. At one month, 84 (30.1%) survivors were assessed with the CPC with 42.8% (n=36) having good neurologic outcome and 57.1% (n=48) poor neurologic outcome. Only two patients with poor neurologic outcome (4.1%) showed improved neurologic status from CPC 3 to CPC 2, during the first 6 months and none showed neurologic improvement after 6 months. The estimated 3-year survival was much higher for CPC 1 (96.4%) than for CPC 4 (24.2%) survivors. CONCLUSIONS Neurologic recovery of OHCA survivors with poor neurologic outcomes at one month was rare and did not occur more than 6 months after cardiac arrest.

Prognostic Value of Timing of Antibiotic Administration in Patients With Septic Shock Treated With Early Quantitative Resuscitation

Background:The Surviving Sepsis Campaign recommends initiating broad-spectrum antibiotic treatment within 1 hour of septic shock recognition. However, there is controversy regarding this owing to contradictory studies. This study investigated the relationship between the antibiotic administration interval and 28-day mortality in septic shock patients treated with an early quantitative resuscitation protocol in an emergency department (ED). Methods:715 consecutive septic shock patients were prospectively collected from January 2010 to December 2012. Of these, 426 patients developed shock at or after initial assessment, and the time of initial antibiotic administration was recorded. The primary outcome was 28-day mortality. Results:The median antibiotic administration interval was 91.5 (47.0–158.0) minutes, and the 28-day mortality was 20.0%. Mortality did not change with hourly delays in antibiotic administration up to 5 hours after shock recognition: 1 hour (odds ratio [OR]: 0.81, 95% confidence interval [CI]: 0.45–1.45), 2 hours (OR: 0.72, 95% CI: 0.40–1.29) and 3 hours (OR: 0.61, 95% CI: 0.30–1.25). However, inability to achieve early resuscitation goals (OR: 1.94, 95% CI: 1.07–3.51), sequential organ failure assessment score (OR: 1.30, 95% CI: 1.17–1.44) and lactic acid concentration (OR: 1.66, 95% CI: 1.11–2.49) were significantly associated with an increased risk of 28-day mortality. Conclusions:Among septic shock patients who underwent early quantitative resuscitation in an ED, mortality did not increase with hourly delays in antibiotic administration. These data call into question the strength of the association between hourly delays in antibiotic administration and mortality in septic shock patients.

Cumulative Query Method for Influenza Surveillance Using Search Engine Data

Background Internet search queries have become an important data source in syndromic surveillance system. However, there is currently no syndromic surveillance system using Internet search query data in South Korea. Objectives The objective of this study was to examine correlations between our cumulative query method and national influenza surveillance data. Methods Our study was based on the local search engine, Daum (approximately 25% market share), and influenza-like illness (ILI) data from the Korea Centers for Disease Control and Prevention. A quota sampling survey was conducted with 200 participants to obtain popular queries. We divided the study period into two sets: Set 1 (the 2009/10 epidemiological year for development set 1 and 2010/11 for validation set 1) and Set 2 (2010/11 for development Set 2 and 2011/12 for validation Set 2). Pearson’s correlation coefficients were calculated between the Daum data and the ILI data for the development set. We selected the combined queries for which the correlation coefficients were .7 or higher and listed them in descending order. Then, we created a cumulative query method n representing the number of cumulative combined queries in descending order of the correlation coefficient. Results In validation set 1, 13 cumulative query methods were applied, and 8 had higher correlation coefficients (min=.916, max=.943) than that of the highest single combined query. Further, 11 of 13 cumulative query methods had an r value of ≥.7, but 4 of 13 combined queries had an r value of ≥.7. In validation set 2, 8 of 15 cumulative query methods showed higher correlation coefficients (min=.975, max=.987) than that of the highest single combined query. All 15 cumulative query methods had an r value of ≥.7, but 6 of 15 combined queries had an r value of ≥.7. Conclusions Cumulative query method showed relatively higher correlation with national influenza surveillance data than combined queries in the development and validation set.

Intracardiac thrombus formation induced by carbon monoxide poisoning

Introduction: Carbon monoxide (CO) is one of the leading causes of poisoning; it inhibits oxygen delivery, subsequently causing ischemic changes and ultimately death by multiorgan failure. Furthermore, thromboembolic episodes due to CO poisoning have been reported. However, intracardiac thrombus formation following exposure to CO has been very rarely described. Here, a case of right atrial large thrombus formation after CO poisoning is presented. Case presentation: A previously healthy 24-year-old woman was referred for CO poisoning. She has attempted suicide, and her initial mental status was drowsy with focal memory loss. Her initial CO fraction was 16%, and initial laboratory data showed creatinine kinase-myocardial bound of 90.6 ng/mL (upper limit 5 ng/mL) and troponin I of 1.899 ng/mL (upper limit 1.5 ng/mL). A transthoracic echocardiography was performed 24 h after the accident, revealing a 30 × 15 mm nodular echogenic mass in the right atrium. Anticoagulation with low-molecular-weight heparin was started along with hyperbaric oxygen therapy. After 7 days of heparinization, the large thrombus in right atrium had resolved. Conclusion: This report describes an intracardiac thrombus formation induced by CO poisoning. Because intracardiac thrombus can result in pulmonary embolism and cerebral embolic infarction, its consideration following CO poisoning is important.

Predicting Outcome With Diffusion-Weighted Imaging in Cardiac Arrest Patients Receiving Hypothermia Therapy: Multicenter Retrospective Cohort Study.

Objectives: Many comatose patients following cardiac arrest have ischemic brain injury. Diffusion-weighted imaging is a sensitive tool to identify hypoxic-ischemic brain injury. The accurate prediction of the prognosis for comatose cardiac arrest survivors has been challenging, and thus, a multimodal approach, combining diffusion-weighted image findings, could be feasible. The aim of this study was to assess regional brain injury on diffusion-weighted imaging and to test the potential association with its neurologic outcome in patients treated with target temperature management after out-of-hospital cardiac arrest. Design and Setting: A multicenter, registry-based, retrospective cohort study was conducted using cases from 24 hospitals across South Korea. Of the 930 adult (≥ 18 yr) nontraumatic out-of-hospital cardiac arrest patients treated with target temperature management between January 2007 and December 2012 at these hospitals, we included the patients who underwent brain diffusion-weighted imaging in the first week after cardiac arrest. The brain regions examined included the four cerebral lobes, basal ganglia-thalamus, brain stem, and cerebellum. Imaging results were compared between a good neurologic outcome, defined as a cerebral performance category score of 1 or 2, and a poor neurologic outcome (cerebral performance category score ≥ 3). Measurement and Main Results: Poor neurologic outcome occurred in 118 of the 172 patients analyzed (68.6%). Positive diffusion-weighted image findings, defined as any regional brain injury lesion in diffusion-weighted imaging, were present in 106 patients. Positive diffusion-weighted image findings had 93% sensitivity, 86% specificity, 76% positive predictive value, and 96% negative predictive value for a poor neurologic outcome. The poor outcome group had higher numbers of affected brain lesions than the good outcome group (3.8 ± 1.9 vs 0.1 ± 0.6; p < 0.01). By multivariate analysis, positive diffusion-weighted image findings (odds ratio, 58.2; 95% CI, 13.29–254.91) and lack of a shockable rhythm (odds ratio, 0.13; 95% CI, 0.03–0.57) were associated with a poor neurologic outcome. Conclusions: Diffusion-weighted imaging allows reliable prediction of poor neurologic outcome in comatose patients treated with target temperature management after out-of-hospital cardiac arrest. Further prospective validation study will be required to generalize this result.

Advanced radiology utilization in a tertiary care emergency department from 2001 to 2010.

Objective To evaluate the utilization trends of advanced radiology, i.e. computed tomography (CT) and magnetic resonance imaging (MRI), examination in an emergency department (ED) of an academic medical center from 2001 to 2010. Patients and Methods We assessed the overall CT and MRI utilization, and the ED patient encounters. Each examination was evaluated according to the patient’s age and anatomically relevant regions. Results During the study period, 737,760 patient visited the ED, and 156,287 CT and 35,018 MRI examinations were performed. The number of annual ED patients increased from 63,770 in 2001 to 94,609 in 2010 (P = 0.018). The rate of CT utilization increased from 105.5 per 1000 patient visits in 2001 to 289.2 in 2010 (P<0.001), and the rate of MRI utilization increased from 8.1 per 1000 patient visits in 2001 to 74.6 in 2010 (P<0.001). In all of the patient age groups, the overall CT and MRI utilization increased. The greater the patient age, the more likely the use of advanced radiology [CT: 87.1 per 1000 patients in age <20 vs. 293.9 per 1000 in age>60 (P<0.001); MRI: 5.1 per 1000 patients in age <20 vs. 108.7 per 1000 in age>60 (P<0.001)]. Abdomen-pelvis (40.2%) and the head (35.7%) comprised the majority of CT scans, while the head (86.4%) comprised the majority of MRI examinations. The rates of advanced radiology use increased across all anatomical regions, with the highest increase being in chest CT (5.9 per 1000 to 49.2) and head MRI (7.2 per 1000 to 61.9). Conclusion We report a three-fold and nine-fold increase in the use of CT and MRI, respectively, during the study period. Additional studies will be required to understand the causes of this change and to determine the effect of advanced radiology utilization on the patient outcome.

Optimal insertion depth of central venous catheters—Is a formula required? A prospective cohort study

INTRODUCTION To determine the optimal length for initial insertion of central venous catheters (CVCs) and to evaluate whether a recommended depth predicted optimal positioning of CVCs. MATERIALS AND METHODS All patients who were CVC-cannulated and who underwent chest computed tomography (CT) during a 10-month period were included. We measured the distance from catheter insertion to the superior vena cava/right atrium (SVC/RA) junction and calculated a recommended insertion depth. We compared the accuracy of the recommended depth with that suggested by the formula of Peres for predicting optimal positioning of a CVC. RESULTS Of the 1238 patients who were CVC-cannulated over 10 months, 106 underwent chest CT. Based on the mean distance from the CVC insertion point to the distal SVC, we determined that the recommended depth of insertion should be 14 cm for the right subclavian vein, 15 cm for the right internal jugular vein, 17 cm for the left subclavian vein and 18 cm for left internal jugular vein. Using these guidelines, initial placement of a CVC in the distal SVC was more accurate than when the Peres formula was used (91.5% vs. 77.4%, p<0.05). CONCLUSIONS For Asian populations, we found that these guidelines are more accurate than those derived from the Peres formulae and more simple to use, thus increasing the likelihood of optimal tip location within the SVC on the first attempt and eliminating the need for later repositioning.