Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Chiwon Ahn is active.

Publication


Featured researches published by Chiwon Ahn.


Scientific Reports | 2016

Efficacy of extracorporeal cardiopulmonary resuscitation compared to conventional cardiopulmonary resuscitation for adult cardiac arrest patients: a systematic review and meta-analysis

Chiwon Ahn; Wonhee Kim; Youngsuk Cho; Kyu-Sun Choi; Bo-Hyoung Jang; Tae Ho Lim

We performed a meta-analysis to compare the impact of extracorporeal cardiopulmonary resuscitation (ECPR) to that of conventional cardiopulmonary resuscitation (CCPR) in adult patients who experience cardiac arrest of cardiac origin. A literature search was performed using criteria set forth in a predefined protocol. Report inclusion criteria were that ECPR was compared to CCPR in adult patients with cardiac arrest of cardiac origin, and that survival and neurological outcome data were available. Exclusion criteria were reports describing non-cardiac origin arrest, review articles, editorials, and nonhuman studies. The efficacies of ECPR and CCPR were compared in terms of survival and neurological outcome. A total of 38,160 patients from 7 studies were ultimately included. ECPR showed similar survival (odds ratio [OR] 2.26, 95% confidence interval [CI] 0.45–11.20) and neurologic outcomes (OR 3.14, 95% CI 0.66–14.85) to CCPR in out-of-hospital cardiac arrest patients. For in-hospital cardiac arrest (IHCA) patients, however, ECPR was associated with significantly better survival (OR 2.40, 95% CI 1.44–3.98) and neurologic outcomes (OR 2.63, 95% CI 1.38–5.02) than CCPR. Hence, ECPR may be more effective than CCPR as an adjuvant therapy for survival and neurologic outcome in cardiac-origin IHCA patients.


Resuscitation | 2016

Smartwatches as chest compression feedback devices: A feasibility study

Yeongtak Song; Youngjoon Chee; Jaehoon Oh; Chiwon Ahn; Tae Ho Lim

BACKGROUND Recently, there have been attempts to use smartphones and smartwatches as the feedback devices to improve the quality of chest compressions. In this study, we compared chest compression depth feedback accuracy between a smartphone and a smartwatch in a hands-only cardiopulmonary resuscitation scenario, using a manikin with a displacement sensor system. METHODS Ten basic life support providers participated in this study. Guided by the chest compression depths displayed on the monitor of a laptop, which received data from the manikin, each participant performed 2min of chest compressions for each target depth (35mm and 55mm) on a manikin while gripping a smartphone and wearing a smartwatch. Participants had a rest of 1h between the instances, and the first target depth was set at random. Each chest compression depth data value from the smartphone and smartwatch and a corresponding reference value from the manikin with the displacement system were recorded. To compare the accuracy between the smartphone and smartwatch, the errors, expressed as the absolute of the differences between the reference and each device, were calculated. RESULTS At both target depths, the error of the smartwatch were significantly smaller than that of the smartphone (the errors of the smartphone vs. smartwatch at 35mm: 3.4 (1.3) vs. 2.1 (0.8) mm; p=0.008; at 55mm: 5.3 (2.8) vs. 2.3 (0.9) mm; p=0.023). CONCLUSION The smartwatch-based chest compression depth feedback was more accurate than smartphone-based feedback.


Clinical and experimental emergency medicine | 2015

Variation of availability and frequency of emergency physician-performed ultrasonography between adult and pediatric patients in the academic emergency department in Korea

Chiwon Ahn; Changsun Kim; Bo Seung Kang; Hyuk Joong Choi; Jun Hwi Cho

Objective This study investigates the availability and frequency of emergency physician-performed ultrasonography (USG) in the emergency department (ED) and the status of USG training programs in emergency medicine residencies in academic EDs in Korea. Methods In spring 2014, a link to a 16-question, multiple-choice, and rating scale web-based survey was e-mailed to all 97 academic ED residency training directors in Korea. Results The response rate was 83.5% (81/97). All respondents had their own USG machines in the ED. In total, 82.7% of respondents reported that emergency physician-performed adult USGs were usually conducted daily, whereas only 23.6% performed pediatric USGs daily. Moreover, 55.5% performed pediatric USG fewer than once a week. 74.1% of respondents had education programs for adult USG in residency training, but only 21.0% had programs for pediatric USG. There was a high association between the presence of education programs and the use of USG in both groups. The faculty members who most commonly participated in teaching ED residents how to perform USG were emergency physicians (67.9%). Only 17.3% of respondents reported that they always supported a quality assurance process. The training directors generally agreed with the advantages in emergency physician-performed USGs. Conclusion The availability of ultrasound machines was high both for adult and pediatric EDs. Nevertheless, the frequency of Emergency physician-performed USG for pediatric patients was low, which was related to the lack of the training programs for treating pediatric patients.


American Journal of Emergency Medicine | 2015

Proper target depth of an accelerometer-based feedback device during CPR performed on a hospital bed: a randomized simulation study

Sanghyun Lee; Jaehoon Oh; Hyunggoo Kang; Wonhee Kim; Youngjoon Chee; Yeongtak Song; Chiwon Ahn; Jun Hwi Cho

PURPOSE Feedback devices are used to improve chest compression (CC) quality related to survival rates in cardiac arrest. However, several studies have shown that feedback devices are not sufficiently reliable to ensure adequate CC depth on soft surfaces. Here, we determined the proper target depth of feedback (TDF) using an accelerometer during cardiopulmonary resuscitation in hospital beds. METHODS In prospective randomized crossover study, 19 emergency physicians performed CCs for 2 minutes continuously on a manikin in 2 different beds with 3 TDFs (5, 6, and 7 cm). We measured CC depth, the proportion of accurate compression depths, CC rate, the proportion of incomplete chest decompressions, the velocity of CC (CC velocity), the proportion of time spent in CC relative to compression plus decompression (duty cycle), and the time spent in CC (CC time). RESULTS Mean (SD) CC depths at TDF 5, 6, and 7 were 45.42 (5.79), 52.68 (4.18), and 58.47 (2.48) on one bed and 46.26 (4.49), 53.58 (3.15), and 58.74 (2.10) mm on the other bed (all P<.001), respectively. The proportions of accurate compression depths and CC velocity at TDF 5, 6, and 7 differed significantly according to TDF on both beds (all P<.001).The CC rate, CC time, and proportion of incomplete chest decompression did not differ on both beds (all P>.05). The duty cycle differed significantly on only B2. CONCLUSIONS The target depth of the real-time feedback device should be at least 6 cm but should not exceed 7 cm for optimal CC on patients on hospital beds.


Scientific Reports | 2018

The delta neutrophil index (DNI) as a prognostic marker for mortality in adults with sepsis: a systematic review and meta-analysis

Chiwon Ahn; Wonhee Kim; Tae Ho Lim; Youngsuk Cho; Kyu-Sun Choi; Bo-Hyoung Jang

We performed a meta-analysis to seek evidence for the usefulness of the delta neutrophil index (DNI) as a prognostic blood biomarker for mortality in the early stage of sepsis in adults. A literature search was performed using criteria set forth in a predefined protocol. Studies of adults with sepsis that provided a DNI measurement and that had mortality as the outcome, were included. Review articles, editorials, and non-human studies were excluded. The methodological quality of identified studies was assessed independently by two authors using the Quality in Prognosis Studies (QUIPS) tool. A total of 1,822 patients from eleven studies were ultimately included. Standardized mean differences between non-survivors and survivors were compared. An elevated DNI was associated with mortality in patients with sepsis (standardized mean difference [SMD] 1.22; 95% confidence interval 0.73–1.71; I2 = 91%). After excluding two studies—one that included paediatric patients and one with a disproportionately low mortality rate—heterogeneity was minimized (SMD 0.74, 95% confidence interval 0.53–0.94; I2 = 43%). Overall, the findings suggest that high DNI values are associated with mortality in septic patients.


American Journal of Emergency Medicine | 2017

Prognostic role of copeptin after traumatic brain injury: A systematic review and meta-analysis of observational studies

Kyu-Sun Choi; Youngsuk Cho; Bo-Hyoung Jang; Wonhee Kim; Chiwon Ahn; Tae Ho Lim; Hyoung-Joong Yi

Purpose: Copeptin, the C‐terminal portion of provasopressin, has emerged as a novel prognostic marker in neurocritical care, such as in traumatic brain injury (TBI). The aim of this study was to quantitatively assess the prognostic significance of initial plasma copeptin levels in the neurological outcome and mortality after traumatic brain injury. Materials and methods: Six relevant studies with data from 552 patients were included in this meta‐analysis. Results: The plasma copeptin levels were found to be significantly higher in patients who died than in the survivors (standardized mean difference [SMD], 1.80). In the four studies reporting Glasgow outcome scale (GOS) data, patients with unfavorable outcomes had significantly higher copeptin levels than those with favorable outcomes (SMD, 1.62). The plasma copeptin level predicted mortality and unfavorable outcomes (AUC, 0.873; AUC, 0.876). Conclusions: The present meta‐analysis suggests that early measurement of plasma copeptin levels can provide better prognostic information about the functional outcome and mortality in patients with TBI.


PLOS ONE | 2017

Effectiveness of feedback with a smartwatch for high-quality chest compressions during adult cardiac arrest: A randomized controlled simulation study

Chiwon Ahn; Juncheol Lee; Jaehoon Oh; Yeongtak Song; Youngjoon Chee; Tae Ho Lim; Hyunggoo Kang; Hyungoo Shin

Previous studies have demonstrated the potential for using smartwatches with a built-in accelerometer as feedback devices for high-quality chest compression during cardiopulmonary resuscitation. However, to the best of our knowledge, no previous study has reported the effects of this feedback on chest compressions in action. A randomized, parallel controlled study of 40 senior medical students was conducted to examine the effect of chest compression feedback via a smartwatch during cardiopulmonary resuscitation of manikins. A feedback application was developed for the smartwatch, in which visual feedback was provided for chest compression depth and rate. Vibrations from smartwatch were used to indicate the chest compression rate. The participants were randomly allocated to the intervention and control groups, and they performed chest compressions on manikins for 2 min continuously with or without feedback, respectively. The proportion of accurate chest compression depth (≥5 cm and ≤6 cm) was assessed as the primary outcome, and the chest compression depth, chest compression rate, and the proportion of complete chest decompression (≤1 cm of residual leaning) were recorded as secondary outcomes. The proportion of accurate chest compression depth in the intervention group was significantly higher than that in the control group (64.6±7.8% versus 43.1±28.3%; p = 0.02). The mean compression depth and rate and the proportion of complete chest decompressions did not differ significantly between the two groups (all p>0.05). Cardiopulmonary resuscitation-related feedback via a smartwatch could provide assistance with respect to the ideal range of chest compression depth, and this can easily be applied to patients with out-of-hospital arrest by rescuers who wear smartwatches.


Scientific Reports | 2018

The Value of Decreased Thyroid Hormone for Predicting Mortality in Adult Septic Patients: A Systematic Review and Meta-Analysis

Jae Guk Kim; Hyungoo Shin; Wonhee Kim; Tae Ho Lim; Bo-Hyoung Jang; Youngsuk Cho; Kyu-Sun Choi; Chiwon Ahn; Juncheol Lee; Min Kyun Na

Decreased thyroid hormone (TH) has been considered as one of the potential predictors of mortality in sepsis. This study aimed to evaluate the prognostic impact of decreased TH on mortality in septic patients during intensive care unit (ICU) admission. We included studies that assessed thyroid function by measuring the serum thyroid hormone level and in-hospital mortality in adult septic patients. Reviews, case reports, editorials, letters, commentaries, animal studies, duplicate studies, and studies with irrelevant populations and inappropriate controls were excluded. A total of 1,578 patients from eight studies were included. Triiodothyronine levels in non-survivors were relatively lower than that of survivors (6 studies; standardized mean difference [SMD] 2.31; 95% confidence interval (CI), 0.52–4.10; I2 = 97%; P = 0.01). Thyroxine levels in non-survivors were also lower than that of survivors (5 studies; SMD 2.40; 95% CI, 0.91–3.89). There were no statistically significant differences in thyroid-stimulating hormone levels between non-survivors and survivors. The present meta-analysis suggested that the decreased TH during ICU admission might be associated with the increase in mortality in adult septic patients. Hence, the measurement of TH could provide prognostic information on mortality in adult septic patients.


Resuscitation | 2018

Gray matter to white matter ratio for predicting neurological outcomes in patients treated with target temperature management after cardiac arrest: A systematic review and meta-analysis

Min Kyun Na; Wonhee Kim; Tae Ho Lim; Bo-Hyoung Jang; Youngsuk Cho; Kyu-Sun Choi; Hyungoo Shin; Chiwon Ahn; Juncheol Lee; Jae Guk Kim

AIMS This study aimed to evaluate the prognostic accuracy of the gray matter to white matter ratio (GWR) in predicting neurological outcomes in post-cardiac arrest patients treated with target temperature management. DATA SOURCES We systematically searched MEDLINE and EMBASE (Search date: 09/13/2017). Included studies were those evaluating neurological outcomes using the cerebral performance categories scale. We performed a subgroup analysis based on the location of the measurement. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the risk of bias. RESULTS In total, 1150 patients from 10 observational studies were included. GWR of the basal ganglia (BG) average showed the highest value (area under the curve [AUC] 0.96, SE 0.02, Q 0.90) compared with the putamen/posterior limb of internal capsule (AUC 0.93, SE 0.05, Q 0.87), overall average (AUC 0.91, SE 0.02, Q 0.85), and cerebrum (AUC 0.89, SE 0.05, Q 0.82) for prognostic accuracy. Furthermore, the highest pooled diagnostic odd ratio of GWR for predicting poor neurological outcomes was shown for the BG average (21.00, 95% CI 6.85-64.40) followed by the overall average (20.71, 95% CI 9.53-44.98), putamen/posterior limb of internal capsule (16.08, 95% CI 4.36-59.23), and cerebrum (13.96, 95% CI 4.26-45.76). CONCLUSIONS GWR in the early cranial computed tomography scan had high prognostic value in predicting poor neurological outcomes in post-cardiac arrest patients. The BG GWR had the highest prognostic accuracy when compared to other locations of the brain.


PLOS ONE | 2018

Diagnostic accuracy of adding copeptin to cardiac troponin for non-ST-elevation myocardial infarction: A systematic review and meta-analysis

Hyungoo Shin; Bo-Hyoung Jang; Tae Ho Lim; Juncheol Lee; Wonhee Kim; Youngsuk Cho; Chiwon Ahn; Kyu-Sun Choi

Introduction This study aimed to determine the diagnostic accuracy of adding copeptin to cardiac troponin (cTn) on admission to the emergency department (ED) for non-ST elevation myocardial infarction (NSTEMI) compared to cTn alone. Materials and methods A literature search of MEDLINE, EMBASE, and the Cochrane Library was performed (search date: April 13, 2018). Primary studies were included if they accurately reported on patients with symptoms suggestive of acute myocardial infarction and measured both cTn alone and cTn with copeptin upon admission to the ED. The patients with evidence of ST elevation myocardial infarction were excluded. To assess the risk of bias for the included studies, the QUADAS-2 tool was used. Results The study participants included a total of 7,998 patients from 14 observational studies. The addition of copeptin to cTn significantly improved the sensitivity (0.81 [0.74 to 0.87] vs. 0.92 [0.89 to 0.95], respectively, p <0.001) and negative predictive value (0.96 [0.95 to 0.98] vs. 0.98 [0.96 to 0.99], respectively, p <0.001) at the expense of lower specificity (0.88 [0.80 to 0.97] vs. 0.57 [0.49 to 0.65], respectively, p <0.001) compared to cTn alone. Furthermore, adding copeptin to cTn showed significantly lower diagnostic accuracy for NSTEMI compared to cTn alone (0.91[0.90 to 0.92] vs. 0.85 [0.83 to 0.86], respectively, p < 0.001). Conclusions Adding copeptin to cTn improved the sensitivity and negative predictive value for the diagnosis of NSTEMI compared to cTn alone. Thus, adding copeptin to cTn might help to screen NSTEMI early upon admission to the ED.

Collaboration


Dive into the Chiwon Ahn's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge