Showing papers by "Jo Kramer-Johansen published in 2013"

Effects of adrenaline on rhythm transitions in out-of-hospital cardiac arrest

Abstract: Background We wanted to study the effects of intravenous (i.v.) adrenaline (epinephrine) on rhythm transitions during cardiac arrest with initial or secondary ventricular fibrillation/tachycardia (VF/VT). Methods Post hoc analysis of patients included in a randomised controlled trial of i.v. drugs in adult, non-traumatic out-of-hospital cardiac arrest patients who were defibrillated and had a readable electrocardiography recording. Patients who received adrenaline were compared with patients who did not. Cardiac rhythms were annotated manually using the defibrillator data. Results Eight hundred and forty-nine patients were included in the randomised trial of which 223 were included in this analysis; 119 in the adrenaline group and 104 in the no-adrenaline group. The proportion of patients with one or more VF/VT episodes after temporary return of spontaneous circulation (ROSC) was higher in the adrenaline than in the no-adrenaline group, 24% vs. 12%, P = 0.03. Most relapses from ROSC to VF/VT in the no-adrenaline group occurred during the first 20 min of resuscitation, whereas patients in the adrenaline group experienced such relapses even after 20 min. Fibrillations from asystole or pulseless electrical activity, shock resistant VF/VT and the number of rhythm transitions per patient was higher in the adrenalin group compared with the no-adrenalin group: 90% vs. 69%, P < 0.001; 46% vs. 33%, P = 0.006; median 8 (5,13) vs. 2 (1,5), P < 0.001, respectively. Conclusion Patients who received adrenaline had more rhythm transitions from ROSC and non-shockable rhythms to VF/VT.

Time delays and capability of elderly to activate speaker function for continuous telephone CPR.

Abstract: Telephone-CPR (T-CPR) can increase rate of bystander CPR as well as CPR quality. Instructions for T-CPR were developed when most callers used a land line. Telephones today are often wireless and can be brought to the patient. They often have speaker function which further allows the rescuer to receive instructions while performing CPR. We wanted to measure adult lay people’s ability to activate the speaker function on their own mobile phone. Elderly lay people, previously trained in CPR, were contacted by telephone. Participants with speaker function experience were asked to activate this without further instructions, while participants with no experience were given instructions on how to activate it. Participants were divided in three groups; Group 1: Can activate the speaker function without instruction, Group 2: Can activate the speaker function with instruction, and Group 3: Unable to activate the speaker function. Time to activation for group 1 and 2 was compared using Mann-Whitney U-test. Seventy-two elderly lay people, mean age 68 ± 6 years participated in the study. Thirty-five (35)% of the participants were able to activate the speaker function without instructions, 29% with instructions and 36% were unable to activate the speaker function. The median time to activate the speaker function was 8s and 93s, with and without instructions, respectively (p < 0.01). One-third of the elderly could activate speaker function quickly, and two-third either used a long time or could not activate the function.

New pre-arrival instructions can avoid abdominal hand placement for chest compressions

Abstract: To investigate if modified pre-arrival instructions using patient’s arm and nipple line as landmarks could avoid abdominal hand placements for chest compressions. Volunteers were randomized to one of two telephone instructions: “Kneel down beside the chest. Place one hand in the centre of the victim’s chest and the other on top” (control) or “Lay the patient’s arm which is closest to you, straight out from the body. Kneel down by the patient and place one knee on each side of the arm. Find the midpoint between the nipples and place your hands on top of each other” (intervention). Hand placement was conducted on an adult male and documented by laser measurements. Hand placement, quantified as the centre of the compressing hands in the mid-sagittal plane, was compared to the inter-nipple line (INL) for reference and classified as above or below. Fisher’s exact test was used for comparison of proportions. Thirty-six lay people, age range 16–60, were included. None in the intervention group placed their hands in the abdominal region, compared to 5/18 in the control group (p = 0.045). Using INL as a reference, the new instructions resulted in less caudal hand placement, and the difference in mean hand position was 47 mm [95% CI 21,73], p = 0.001. New pre-arrival instructions where the patient’s arm and nipple line were used as landmarks resulted in less caudal hand placements and none in the abdominal region.

Publication of clinical trial protocols – what can we learn?

Abstract: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (SJTREM) receives about 220 submissions for publication every year. Based on the principles of open access publishing, all scientifically sound manuscript that are original and in compliance with ethical and author guidelines will be considered for publication. Such editorial policies are in effect in most journals, and together with rigorous peer-review they are the cornerstones of scientific dissemination. The rejection rates for submitted papers and the citations to published papers are considered when overall quality or impact of a journal is evaluated; however, both these metrics have serious shortcomings and can’t be used for comparison between journals without caution. SJTREM currently rejects 60% of all submitted papers; the current impact factor is 1.85. In clinical medicine we want to provide our patients with the best possible treatment, and we need to know whether some new intervention is more effective than what we have been used to doing. To find out, we need clinical trials. The crucial point in any comparison is to be fair, and in scientific terms this means to rule out as many sources of bias and confounding as possible. Randomization is a powerful tool to ensure that unknown factors will be evenly distributed among the experimental groups, and the randomized controlled trial (RCT) is the golden standard. But even the most elegant study could end up unpublished if the results are unexpected (or even unwanted!), or the results may be tweaked to satisfy a study sponsor’s financial interests. Fear of such publication bias led to registries of clinical trials. Registration has become required for publication in most medical journals [1], and also regulated by laws in some countries. The purpose of such registration is mainly to have publicly disclosure of the ethical considerations, intentions and rationale before recruiting subjects into the trial, and secondarily it will help avoid planning and funding studies that already are running; finally it may serve as a data repository after the end of the study to provide other researchers opportunity to verify or collate results. For journals that must decide on publication, these registries provide opportunity to verify that the submitted paper adheres to the original plan for conduct and analysis. Even so, a recent analysis of 40 RCTs published after 2005 revealed improper presentation of outcomes or analyses in up to 75% of the studies when compared with the original protocol, and late registration into ClinicalTrials.gov in a similar proportion (url: http://www.ncbi.nlm.nih.gov/books/NBK100613/, accessed January 18, 2013). The reasons mentioned above give sound reason to publish or make publicly available full protocols of clinical trials. For the editors, the question remains whether the protocol represents a redundant publication when it is already publicly available in registries. For the competitive researcher, the question may be how to get properly rewarded for the huge amount of work that has been put into protocol development, in a system where counting of publications may define your further funding or promotions. An additional issue of grievance for the publisher may be that even if agreeing to publish the protocol, there may be small chances to receive the final results for publication due to an understandable quest for high-impact journals and prestigious papers. Sten Rubertsson and colleagues here present their protocol from the LINC study, which just finished inclusion of patients. The LINC study is a randomized controlled trial of mechanical chest compressions with LUCAS™ combined with a specific algorithm of chest compressions and defibrillations. After careful editorial consideration, SJTREM has decided to publish the protocol even if the research and analysis plan have been publicly available on ClinicalTrials.gov since 2008 (NTC 00609778). The published protocol provides additional rationale and background for the trial, as well as a detailed description of the organization of the trial; hopefully it may aid others to organize a clinical trial. However, as the trial is now concluded, there is little left for peer-review to change besides issues of language and clarity. We will therefore print the original protocol more or less as submitted and instead provide a critical commentary of the protocol in this editorial. The authors have the opportunity to respond septely. As an aid in this process, we will follow the 10-dimensional Trial Quality assessment list suggested by Berger and Alperson [2]. This paper aims at identifying unique aspects that may influence trial quality, and differs from previous systems for trial assessment by proposing that the final “quality score” should be obtained by multiplying individual scores. We have avoided the scoring, though, and apply the list in only in a “check-list” or qualitative way. We will also briefly comment on what was made public on ClinicalTrials.gov, and finally on what we perceive as strengths and weaknesses of the study.

Probabilistic classification approaches for cardiac arrest rhythm interpretation during resuscitation

Abstract: Our ultimate objective is to develop methodology for resuscitation data analysis that involves monitoring of the patients response, the quality of therapy, and to understand the interplay between therapy and response. To this end, methods to reliably detect the rhythm types during a resuscitation episode are needed. The objective of this study was to develop machine learning algorithms to recognize the rhythms appearing during a resuscitation episode. In this study, we used a probabilistic framework to classify different cardiac arrest rhythms. We propose two different classifiers; naive Bayes and logistic regression classifier.

Abstract 15393: High Quality CPR With Optimized Rescuer-Dispatcher Teamwork

Abstract: Background: Calling the emergency phone number and starting CPR initiates the chain of survival for sudden cardiac arrest outside hospital. Traditional CPR courses teach to call for help and to per...

A simple impedance-based method for ventilation detection during cardiopulmonary resuscitation

Abstract: During cardiopulmonary resuscitation, excessive ventilation rates decrease cardiac output, thus reducing the chance of survival. We have developed a simple method to automatically detect ventilations based on the analysis of the thoracic impedance signal recorded through defibrillation pads. We used 18 out-of hospital cardiac arrest episodes that contained both ventilations provided during chest compressions (CCs) and during pauses in CCs. The detection algorithm first identified fluctuations on the preprocessed impedance signal. Then, it characterized the fluctuations by features for amplitude, duration and slope. Finally, a decision system based on static and dynamic thresholds was applied in order to determine whether each fluctuation corresponded to a ventilation. Sensitivity (Se) and positive predictive value (PPV) for the test set (2831 ventilations) were 97% and 94%, respectively. Before intubation (343 ventilations), Se and PPV were 92% and 79%, and 97% and 97% after intubation. The performance was very similar for intervals with and without CCs. The proposed method could be implemented in automatic external defibrillators for ventilation rate monitoring.

A new algorithm to diagnose during chest compressions: Effect on cardiopulmonary resuscitation delivery

Abstract: Rhythm analysis methods for shock advice during CPR are evaluated in terms of sensitivity and specificity. However, these figures do not convey the real impact that using these methods would have on the delivery of CPR. This study evaluates the impact on CPR delivery of a new rhythm analysis method. First, the original method was modified to increase the reliability of a shock diagnosis by the addition of high and low confidence diagnoses and the combination of several diagnoses before deciding a shock. Compared to the current CPR guidelines, the modified rhythm analysis method showed a 94.4% probability of delivering the shock earlier to patients in shockable rhythms and a 94.1% probability of reducing CPR interruptions for rhythm reassessment in nonshockable rhythms. Although the results are promising further testing is needed on complete resuscitation episodes.