Tae Nyoung Chung

Effect of vehicle speed on the quality of closed-chest compression during ambulance transport

INTRODUCTION Transport of patients with ongoing cardiopulmonary resuscitation (CPR) occurs frequently. It may not be possible to obtain rapid hospital access while maintaining CPR quality, because the ambulances high speed can cause increased vibration and vehicle movement. We aimed to assess how the speed of ambulance affects chest compressions. MATERIALS AND METHODS Five cycles of CPR were performed to the Resusci Anne manikin with the PC skill reporting system by experienced emergency medical technicians in ambulance traveling at one of four different speeds: stationary, 30, 60, or 90km/h. Performance and acceleration data of chest compressions at different speeds were compared using repeated measures analysis of variance (ANOVA). RESULTS Fractions of chest compressions with adequate depth, duty cycles, average rates of chest compressions, and no flow fractions showed significant differences among different speeds (p=0.026, <0.001, <0.001, 0.005, respectively), while average depth of chest compressions did not. Accelerations of 2Hz component and ratios of 3-12Hz to 0-2Hz components showed significant differences among different speeds (p=0.001 for all). None of the outcome variables showed a significant difference between the two types of ambulance. CONCLUSIONS The speed of ambulance affects some aspects in the quality of chest compression during transport. Chest compressions with excessive depth, the average rate of chest compressions, and no-flow fraction increase as the speed of ambulance increase. Increase in the speed of ambulance also causes relative increase of high frequency acceleration in the chest compression, which represents unnecessary movement and force applied.

Estimation of anatomical structures underneath the chest compression landmarks in children by using computed tomography

OBJECTIVE There has been little investigation on the appropriateness of the hand position suggested by various guidelines in paediatric cardiopulmonary resuscitation (CPR). We aimed to identify anatomical structures underneath the chest compression landmarks and tried to find the proper hand position using computed tomography (CT) images for more effective paediatric CPR. PATIENTS AND METHODS This study included a total of 181 paediatric patients who were admitted to Severance Hospital and underwent CTs of chest. We studied structures located under the inter-nipple line and under the lower third of the sternum. The distances from the xiphoid process to the level of the left ventricular outflow tract (LVOT) were measured to find the ceiling on the proper hand position. RESULTS The LVOT (42.0%) and the root of the aorta (21.5%) were more frequently located than the left ventricle under the inter-nipple line, and the liver was located under the lower third of the sternum in a significant number of patients (28.7%). The LVOT was placed 6.8±13.9 mm below the nipple level, but there was no significant difference in the distance from the nipple level to the LVOT among the age groups (p=0.517). CONCLUSIONS The hand position at the inter-nipple line might be too high and that at the lower third of the sternum might be too low as it can compress the liver. Further studies are needed to find the proper hand position for more effective chest compression during paediatric CPR.

A higher chest compression rate may be necessary for metronome-guided cardiopulmonary resuscitation

OBJECTIVES Metronome guidance is a simple and economical feedback system for guiding cardiopulmonary resuscitation (CPR). However, a recent study showed that metronome guidance reduced the depth of chest compression. The results of previous studies suggest that a higher chest compression rate is associated with a better CPR outcome as compared with a lower chest compression rate, irrespective of metronome use. Based on this finding, we hypothesized that a lower chest compression rate promotes a reduction in chest compression depth in the recent study rather than metronome use itself. METHODS One minute of chest compression-only CPR was performed following the metronome sound played at 1 of 4 different rates: 80, 100, 120, and 140 ticks/min. Average compression depths (ACDs) and duty cycles were compared using repeated measures analysis of variance, and the values in the absence and presence of metronome guidance were compared. RESULTS Both the ACD and duty cycle increased when the metronome rate increased (P = .017, <.001). Average compression depths for the CPR procedures following the metronome rates of 80 and 100 ticks/min were significantly lower than those for the procedures without metronome guidance. CONCLUSIONS The ACD and duty cyle for chest compression increase as the metronome rate increases during metronome-guided CPR. A higher rate of chest compression is necessary for metronome-guided CPR to prevent suboptimal quality of chest compression.

Use of Bedside Sonography for Diagnosing Acute Epiglottitis in the Emergency Department A Preliminary Study

The purpose of this study was to investigate the ability of sonography to identify acute epiglottitis in the emergency department.

The usefulness of rapid point-of-care creatinine testing for the prevention of contrast-induced nephropathy in the emergency department.

Background Renal dysfunction is the most important factor to consider when predicting a patients risk of developing contrast-induced nephropathy (CIN). Measurement of creatinine (Cr) via rapid point-of-care blood urea nitrogen/creatinine testing (POCT-BUN/Cr) to determine CIN risk could potentially reduce the time required to achieve an accurate diagnosis and to initiate and complete treatment in the emergency department (ED). The aim of our study was to compare the results of POCT-BUN/Cr and reference laboratory tests for BUN and serum Cr. Materials and methods A retrospective analysis of suspected stroke patients who presented between November 2009 and November 2010, and had BUN and Cr levels measured by POCT-BUN/Cr, and the reference laboratory tests performed with the blood sample which was transferred to the central laboratory by an air-shoot system. Two assays were conducted on the whole blood (POCT) and serum (reference) by trained technicians. The time interval from arrival at the ED to reporting of the results was assessed for both assays via a computerised physician order entry system. Results The mean standard deviation (SD) interval from arrival at the ED to reporting of the results was 11.4 (4.9) min for POCT-BUN/Cr and 46.8 (38.5) min for the serum reference laboratory tests (p<0.001). Intra-class correlation coefficient (ICC) analysis demonstrated a high level of agreement (the consistency agreement) between POCT and the serum reference tests for both BUN (ICC=0.914) and Cr (ICC=0.980). Conclusions This study suggests that POCT-BUN/Cr results correlate well with those of serum reference tests in terms of BUN and Cr levels and, in turn, predicting CIN. POCT-BUN/Cr is easily performed with a rapid turnaround time, suggesting its use in the ED may have substantial clinical benefit.

The Specific Effect of Metronome Guidance on the Quality of One-person Cardiopulmonary Resuscitation and Rescuer Fatigue

BACKGROUND Metronome guidance is a simple and economic feedback method of guiding cardiopulmonary resuscitation (CPR). It has been proven for its usefulness in regulating the rate of chest compression and ventilation, but it is not yet clear how metronome use may affect compression depth or rescuer fatigue. STUDY OBJECTIVE The aim of this study was to assess the specific effect that metronome guidance has on the quality of CPR and rescuer fatigue. METHODS One-person CPRs were performed by senior medical students on Resusci Anne® manikins (Laerdal, Stavanger, Norway) with personal-computer skill-reporting systems. Half of the students performed CPR with metronome guidance and the other half without. CPR performance data, duration, and before-after trial differences in mean arterial pressure (MAP) and heart rate (HR) were compared between groups. RESULTS Average compression depth (ACD) of the first five cycles, compression rate, no-flow fraction, and ventilation count were significantly lower in the metronome group (p=0.028, < 0.001, 0.001, and 0.041, respectively). Total CPR duration, total work (ACD × total compression count), and the before-after trial differences of the MAP and HR did not differ between the two groups. CONCLUSIONS Metronome guidance is associated with lower chest compression depth of the first five cycles, while shortening the no-flow fraction and the ventilation count in a simulated one-person CPR model. Metronome guidance does not have an obvious effect of intensifying rescuer fatigue.

Performance of an automated external defibrillator during simulated rotor-wing critical care transports

OBJECTIVE This study aimed to evaluate whether an automated external defibrillator (AED) was accurate enough to analyze the heart rhythm during a simulated rotor wing critical care transport. We hypothesized that AED analysis of the simulated rhythms during a helicopter flight would result in significant errors (i.e., inappropriate shocks, analysis delay). METHODS Three commercial AEDs were tested for analyzing the heart rhythm in a helicopter using a manikin and a human volunteer. Ventricular fibrillation (VF), sinus rhythm, and asystole were simulated by using an arrhythmia simulator of the manikin. The intervals from analysis to shock recommendation were collected on a stationary and in-motion helicopter. Sensitivity and specificity of three AEDs were also calculated. Vibration intensities were measured with a digital vibration meter placed on the chest of the manikin/human volunteer both on the stretcher and on the floor of the helicopter. RESULTS All AEDs correctly recommended shock delivery for the cardiac rhythms of the manikin. Sensitivity for VF was 100.0% (95% CI 91.2-100.0) and specificity for sinus rhythm and asystole were 100.0% (95% CI 91.2-100.0). Although the recorded ECG rhythms of the volunteer in an in-motion helicopter showed baseline artifacts, all AEDs analyzed the cardiac rhythm of the volunteer correctly and did not recommend shock delivery. On the floor of the helicopter, the median measured vibration intensity was 6.6 m/s(2) (IQR 5.5-7.7 m/s(2)) with significantly less vibrations transmitted to the manikin/human volunteer chest (manikin median 3.1 m/s(2), IQR 2.2-4.0 m/s(2); human volunteer median 0.95 m/s(2), IQR 0.65-1.25 m/s(2)). CONCLUSION This study suggested that current AEDs could analyze the heart rhythm correctly during simulated helicopter transport. Further studies using an animal model would be needed before applying to patients.

Unilateral blindness with third cranial nerve palsy and abnormal enhancement of extraocular muscles on magnetic resonance imaging of orbit after the ingestion of methanol

Methanol is generally known to cause visual impairment and various systemic manifestations. There are a few reported specific findings for methanol intoxication on magnetic resonance imaging (MRI) of the brain. A case is reported of unilateral blindness with third cranial nerve palsy oculus sinister (OS) after the ingestion of methanol. Unilateral damage of the retina and optic nerve were confirmed by fundoscopy, flourescein angiography, visual evoked potential and electroretinogram. The optic nerve and extraocular muscles (superior rectus, medial rectus, inferior rectus and inferior oblique muscle) were enhanced by gadolinium-DTPA on MRI of the orbit. This is the first case report of permanent monocular blindness with confirmed unilateral damage of the retina and optic nerve, combined with third cranial nerve palsy after methanol ingestion.

The usefulness of the Kurashiki prehospital stroke scale in identifying thrombolytic candidates in acute ischemic stroke.

Purpose The severity of a stroke cannot be described by widely used prehospital stroke scales. We investigated the usefulness of the Kurashiki Prehospital Stroke Scale (KPSS) for assessing the severity of stroke, compared to the National Institutes of Health Stroke Scale (NIHSS), in candidate patients for intravenous or intra-arterial thrombolysis who arrived at the hospital within 6 hours of symptom onset. Materials and Methods We retrospectively analyzed a prospective registry database of consecutive patients included in the Emergency Stroke Therapy program. In the emergency department, the KPSS was assessed by emergency medical technicians. A cutoff KPSS score was estimated for candidates of thrombolysis by comparing KPSS and NIHSS scores, as well as for patients who actually received thrombolytic therapy. Clinical outcomes were compared between patients around the estimated cut-off. The independent predictors of outcomes were determined using multivariate logistic regression analysis. Results Excellent correlations were demonstrated between KPSS and NIHSS within 6 hours (R=0.869) and 3 hours (R=0.879) of hospital admission. The optimal threshold value was a score of 3 on the KPSS in patients within 3 hours and 6 hours by Youdens methods. Significant associations with a KPSS score ≥3 were revealed for actual intravenous administration of tissue plasminogen activator (IV-tPA) usage [odds ratio (OR) 125.598; 95% confidence interval (CI) 16.443-959.368, p<0.0001] and actual IV-tPA or intra-arterial urokinase (IA-UK) usage (OR 58.733; 95% CI 17.272-199.721, p<0.0001). Conclusion The KPSS is an effective prehospital stroke scale for identifying candidates for IV-tPA and IA-UK, as indicated by excellent correlation with the NIHSS, in the assessment of stroke severity in acute ischemic stroke.

Mechanical ventilation in the emergency department for 24 hours or longer is associated with delayed weaning

PURPOSE We examined various aspects of critical care to identify factors in the emergency department (ED) that affected the overall duration of mechanical ventilation (MV). We specifically focused on whether 24 hours of ED MV affected the weaning success and the duration of MV. MATERIALS AND METHODS Mechanical ventilation cases that started in the ED because of purely respiratory problems were enrolled in the retrospective cohort. We recorded demographic data, duration of MV in ED, various severity scores, previously known factors of prolonged MV, and achievement of ventilator weaning. All the significant factors in univariate survival analyses were included in a multivariate analysis. RESULTS The estimated median of the entire duration of MV was longer in patients who received 24 hours or more of MV in ED compared with that of patients who received MV for less than 24 hours (33.0 vs 15.4 days, P = .003). Mechanical ventilation for longer than 24 hours in the ED remained a significant factor that prolonged the entire MV duration in the multivariate analysis (hazard ratio, 0.577; P = .019). Hypoalbuminemia and abbreviated mortality in ED sepsis (MEDS) score were also independently correlated (P ≤ .001 for both). CONCLUSIONS Mechanical ventilation in the ED for 24 hours or longer is associated with delayed ventilator weaning.