D. Mauer

Comparison of Standard Cardiopulmonary Resuscitation Versus the Combination of Active Compression-Decompression Cardiopulmonary Resuscitation and an Inspiratory Impedance Threshold Device for Out-of-Hospital Cardiac Arrest

Background—Active compression-decompression (ACD) CPR combined with an inspiratory impedance threshold device (ITD) improves vital organ blood flow during cardiac arrest. This study compared survival rates with ACD+ITD CPR versus standard manual CPR (S-CPR). Methods and Results—A prospective, controlled trial was performed in Mainz, Germany, in which a 2-tiered emergency response included early defibrillation. Patients with out-of-hospital arrest of presumed cardiac pathogenesis were sequentially randomized to ACD+ITD CPR or S-CPR by the advanced life support team after intubation. Rescuers learned which method of CPR to use at the start of each work shift. The primary end point was 1-hour survival after a witnessed arrest. With ACD+ITD CPR (n=103), return of spontaneous circulation and 1- and 24-hour survival rates were 55%, 51%, and 37% versus 37%, 32%, and 22% with S-CPR (n=107) (P =0.016, 0.006, and 0.033, respectively). One- and 24-hour survival rates in witnessed arrests were 55% and 41% with ACD+ITD CPR versus 33% and 23% in control subjects (P =0.011 and 0.019), respectively. One- and 24-hour survival rates in patients with a witnessed arrest in ventricular fibrillation were 68% and 58% after ACD+ITD CPR versus 27% and 23% after S-CPR (P =0.002 and 0.009), respectively. Patients randomized ≥10 minutes after the call for help to the ACD+ITD CPR had a 3 times higher 1-hour survival rate than control subjects (P =0.002). Hospital discharge rates were 18% after ACD+ITD CPR versus 13% in control subjects (P =0.41). In witnessed arrests, overall neurological function trended higher with ACD+ITD CPR versus control subjects (P =0.07). Conclusions—Compared with S-CPR, ACD+ITD CPR significantly improved short-term survival rates for patients with out-of-hospital cardiac arrest. Additional studies are needed to evaluate potential long-term benefits of ACD+ITD CPR.

Active compression-decompression resuscitation: a prospective, randomized study in a two-tiered EMS system with physicians in the field

Improved cardiopulmonary circulation with active compression-decompression cardiopulmonary resuscitation (ACD-CPR) has been demonstrated in studies using different animal models and a small number of humans in cardiac arrest (CA). However, prehospital studies have shown both positive and no extra benefit of ACD-CPR on return of spontaneous circulation (ROSC), hospital admission and discharge rates. The aim of our prospective study was to compare standard manual CPR (S-CPR) with ACD-CPR as the initial technique of resuscitating patients with out-of-hospital CA, with respect to survival rates and neurological outcome. Patients with out-of-hospital CA treated by emergency medical services (EMS) personnel were randomly assigned to one of two groups (ACD-CPR versus S-CPR). Time intervals to key measures were documented by means of on-line tape-recording. Neurological outcome was assessed using standard scoring systems (cerebral and overall performance categories (CPC and OPC)). A total of 220 patients (S-CPR, n = 114: ACD-CPR, n = 106) were included in the study in a random order. The treatment groups were similar with respect to age, sex, time interval from collapse to CPR, defibrillation and first adrenaline medication. There was no difference between the ACD group and the standard CPR group in terms of ROSC (50.9% vs. 59.6%), hospital admission (33% vs. 33.3%), hospital discharge (16% vs. 14%), or CPC and OPC (1.82 vs. 2.13 and 2.06 vs. 2.25, respectively). Concerning complications of CPR, there was no difference between the groups. In our two-tiered EMS system with physician-staffed ambulances, ACD-CPR neither improved nor impaired survival rates and neurological prognosis in patients with out-of-hospital cardiac arrest. The new CPR technique did not increase the complications associated with the resuscitation effort.

Effect of active compression-decompression resuscitation (ACD-CPR) on survival: a combined analysis using individual patient data.

Active compression decompression resuscitation (ACD-CPR) has been developed as an alternative to standard cardiopulmonary resuscitation (S-CPR). To determine the effect of ACD-CPR on survival and neurologic outcome in patients with out-of-hospital cardiac arrest, this combined analysis involved individual patient data from 2866 patients from seven separate randomized prospective prehospital studies who had received ACD-CPR or S-CPR after out-of-hospital cardiac arrest in seven international sites. Significant improvement in 1-h survival (odds ratio (OR) = 0.83; confidence interval (CI): 0.695-0.99; P < 0.05) was found with ACD-CPR (n = 1410) versus S-CPR (n = 1456). The odds ratio for hospital discharge after ACD-CPR was similar (OR = 0.82; CI: 0.609-1.107, P = NS), but this finding was not statistically significant. Using the chi2-test for trend, there was a significant improvement in overall survival with ACD-CPR (P < 0.05) versus S-CPR. This improvement was largely due to the influence of results from one study site. Neurological outcome and complication rates were comparable between groups. Further study is needed to determine which emergency medical services systems may benefit from out-of-hospital use of ACD-CPR.

Carbon dioxide levels during pre-hospital active compression-decompression versus standard cardiopulmonary resuscitation

In a prospective randomised study we investigated end-tidal carbon dioxide levels during standard versus active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) assuming that the end-tital carbon dioxide reflects cardiac output during resuscitation. In each group 60 patients with out-of-hospital cardiac arrest were treated either with the standard or the ACD method. End-tidal CO2 (p(et)CO2, mmHg) was assessed with a side-stream capnometer following intubation and then every 2 min up to 10 min or restoration of spontaneous circulation (ROSC). There was no difference in p(et)CO2 between both patient groups. However, CO2 was significantly higher in patients who were admitted to hospital as compared to patients declared dead at the scene. All of the admitted patients had a p(et)CO2 of at least 15 mmHg no later than 2 min following intubation, none of the dead patients ever exceeded 15.5 mmHg. From these data we conclude that capnometry adds valuable information to the estimation of a patients prognosis in the field (threshold, 15 mmHg), but we could not detect any difference in p(et)CO2 between ACD and standard CPR.

Early defibrillation by emergency physicians or emergency medical technicians? A controlled, prospective multi-centre study

UNLABELLED In a controlled, prospective multi-centre study, defibrillation by emergency medical technicians (EMTs) was compared with the current standard of care in Germany--defibrillation by emergency physicians (EPs)-in order to answer the following questions: can EMTs in a two-tiered emergency medical services (EMS) system with physicians in the field defibrillate earlier than, and as safely as EPs? Does defibrillation by EMTs (study group) affect survival rate and long-term prognosis of patients in ventricular fibrillation (VF), as compared with the current national standards in resuscitation (basic cardiopulmonary resuscitation (CPR) by EMTs, and defibrillation by physicians: control group? METHODS Prior to the onset of the study, all EMTs completed retraining in basic life support (BLS). Randomly assessed EMTs were then trained to use semi-automatic defibrillators. With the help of on-line tape recordings, the complete resuscitation sequence was evaluated. Follow-up of the patients was carried out with the help of the Glasgow Coma Scale as well as Pittsburgh Cerebral and Overall Performance Categories. RESULTS A total of 159 patients with VF were included in the study. In 121 cases, collapse was witnessed. Of the patients receiving defibrillation by EMTs 25% were discharged from hospital alive, compared to 24% of the patients defibrillated by EPs. Of the study patients 67% were defibrillated within 12 min, while the percentage of control patients was 46%. Study patients were defibrillated earlier (P < 0.01), the return of spontaneous circulation (ROSC) was achieved earlier (P < 0.05), and the rate of patients requiring no adrenalin during resuscitation was higher in the study group (P < 0.05). The total amount of adrenalin administered in the study group was lower (P < 0.05). No statistically significant differences were found concerning the neurologic long-term prognosis. CONCLUSIONS In our study, EMT defibrillation was equally effective as defibrillation by EPs, but failed to improve survival rates or long-term outcome of patients in VF significantly, compared to EP defibrillation. Due to a reduction in the time intervals from collapse to defibrillation and to ROSC, as well as in adrenalin doses, by EMT-defibrillation, EMTs in Germany should defibrillate if they reach a patient prior to an EP, provided they have received continuous medical training and supervision.

The first European pre-hospital active compression-decompression (ACD) cardiopulmonary resuscitation workshop: a report and a review of ACD-CPR

Active compression-decompression cardiopulmonary resuscitation (ACD-CPR) has been evaluated in animal cardiac arrest models and in human outcome studies. Blood flow to the brain and heart is significantly increased during ACD-CPR compared to standard CPR. Transoesophageal Doppler analysis indicates that ACD-CPR increases left ventricular blood volume, velocity of blood flow through the mitral valve (82-140%), and stroke volume (85%). Pressures, such as coronary perfusion-, systolic-, mean-, and diastolic aortic pressures, ETCO2, and tidal volume generated by chest compression and decompression, increase during ACD-CPR compared to standard CPR. Prehospital outcome studies have shown both positive and no extra benefit of ACD-CPR on return of spontaneous circulation, hospital admission, and discharge rates. The ACD-CPR method should be evaluated in patients with witnessed arrest receiving bystander CPR who are found in ventricular fibrillation and do not respond to the three initial DC shocks. There is no evidence that ACD-CPR is worse than standard CPR. Appropriate ACD-CPR training using a standardized curriculum must preceed its implementation. Long-term neurologic outcome studies are needed.

Does standardized mega-code training improve the quality of pre-hospital advanced cardiac life support (ACLS)?☆

The aim of our prospective study was to evaluate the effects of a standardized mega-code and arrhythmia training upon process elements of quality of pre-hospital advanced cardiac life support provided by a physician-staffed mobile intensive care unit. In 145 cases of adult cardiac arrest due to cardiac aetiology, time intervals from arrival of the mobile intensive care unit at the patients side until first ECG diagnosis, first defibrillation, endotracheal intubation, and first epinephrine administration were measured with on-line tape recording, prior to, and following a standardized 8-h arrhythmia and mega-code training. Following the training, patients with asystole or pulseless electrical activity were intubated 1.1 min earlier (P = 0.03), and received epinephrine 1.3 min earlier (P = 0.01) than prior to the training. There were no significant differences in time intervals concerning management of ventricular fibrillation or tachycardia. Neither admission nor discharge rates differed significantly before and after the training. Thus, practical training including rhythm analysis and mega-code session improved the performance of our mobile intensive care unit in cases of asystole and pulseless electrical activity, and, hence, process elements of quality.

Quality of on-site performance in prehospital advanced cardiac life support (ACLS)

UNLABELLED The aim of our prospective study was to assess the structural and procedural quality of an urban emergency medical services (EMS) system providing prehospital basic and advanced cardiac life support (BLS/ACLS), to compare the onsite performance of physicians and non-physicians in ECG diagnosis and defibrillation, and to identify incidence and causes of avoidable delays in the initial treatment sequences. METHODS Between 1 February 1991 and 1 July 1992, 162 on-line tape recordings of prehospital cardiopulmonary resuscitation (CPR) efforts performed by the staff of the EMS system of the city of Mainz were evaluated. After arrival at the patients side, time intervals to initial ACLS steps (first ECG-diagnosis, first defibrillation, endotracheal intubation, first epinephrine administration) were measured. Times to rhythm identification and countershock by EMT-Ds vs. physicians were compared (Mann-Whitney U-test). Time intervals are presented as median values. One-hundred sixty-two adult patients with out-of-hospital cardiac arrests (ventricular fibrillation [VF] or ventricular tachycardia [VT], 72; asystole or electromechanical dissociation [EMD], 90) receiving CPR by EMTs, EMT-Ds, and physicians of the Mainz EMS were included. Patients with arrests due to non-cardiac aetiologies were excluded. RESULTS After arrival at the patients side, for patients with VF/VT, the EMT-Ds took 1:36 min and the physicians took 1:00 min to obtain the first ECG diagnosis (P = 0.004). The first countershock was delivered within 1:42 min by both EMT-Ds and physicians of the mobile intensive care unit (MICU). After diagnosis was established, the EMT-Ds took 0:08 min to defibrillate, whereas the physicians took 0:36 min (P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Early defibrillation by emergency physicians or emergency medical technicians

Zusammenfassung. In einer prospektiven Multicenterstudie wurde der Einfluß der Defibrillation durch Rettungsassistenten im Vergleich zum bisher praktizierten Verfahren (Basismaßnahmen der kardiopulmonalen Reanimation durch Rettungsassistenten und Defibrillation ausschließlich durch den Notarzt) auf die Überlebensrate und die neurologische Langzeitprognose bei 159 Patienten mit außerklinisch aufgetretenem Kammerflimmern untersucht. Alle Zeitintervalle des Reanimationsablaufs und die Behandlungsqualität wurden mittels Diktaphon erfaßt und nachvollzogen. Es bestanden keine signifikanten Unterschiede in der primären Überlebensrate, der Entlassungsrate und der neurologischen Langzeitprognose zwischen den untersuchten Gruppen. Aufgrund deutlicher Unterschiede zugunsten der Studiengruppe (Defibrillation durch Rettungsassistenten) in indirekten Parametern (kürzerer Zeitraum bis zur Wiederherstellung spontaner Kreislaufverhältnisse und größere Anzahl an Patienten, die kein Adrenalin benötigten) und der Tatsache, daß in den untersuchten Zentren der Zeitpunkt bis zur ersten Defibrillation signifikant nach vorne verlagert werden konnte, empfehlen wir die Defibrillation durch Rettungsassistenten: a) wenn sie den Patienten vor dem Notarzt erreichen, b) nach straffem Ausbildungsprogramm und unter kontinuierlicher ärztlicher Kontrolle. Um die Defibrillationsmaßnahme durch Rettungsassistenten effektiver werden zu lassen, müssen tiefgreifende Veränderungen im Rettungssystem vorausgehen: Verkürzung des Zeitintervalls bis zum Beginn von Basismaßnahmen sowie konsequente Durchführung eines gestaffelten Rettungssystems.Abstract. In a controlled prospective randomized study, defibrillation by emergency medical technicians (EMTs) was compared with the current standard of care in Germany (basic life support by EMTs and defibrillation by emergency physicians only) in order to answer the following questions: 1. Does EMT defibrillation improve the survival rate and long-term prognosis of patients in ventricular fibrillation as compared to the current German standards in resuscitation (basic life support by EMTs and defibrillation by emergency physicians)? 2. Are the prerequisites for the use of semiautomatic defibrillators fulfilled in the emergency medical systems (EMS) of the participating centers? Methods. The study phase includes randomization of 121 adult patients with witnessed cardiac arrest and ventricular fibrillation (VF) as first ECG rhythm. Prior to the onset of the study, all EMTs of the participating EMS systems were retrained in basic life support (BLS) measures. In each center, randomly assessed EMT-Ds (EMTs trained in Defibrillation) were trained to use semiautomatic defibrillators. With the help of one-line tape recording, the time intervals during resuscitation and treatment steps were evaluated. Successfully resuscitated patients were followed up with the help of the Glascow Coma Scale and the Pittsburgh Cerebral and Overall Performance Categories. Results. From 1 February 1991 until 28 June 1992, 159 patients with VF were randomized. In 121 cases, collapse was witnessed. 25% (14/57) of the patients receiving defibrillation by EMT-Ds (study group=S) were discharged from the hospital alive. In the control group, 52 patients were defibrillated by emergency physicians, following BLS by EMTs [control group 1=C1; discharged: 29% (15/52)]. Fifty patients received BLS and advanced cardiac life support (ACLS) by the emergency physicians crews [control group 2=C2; discharged 18% (9/50)]. In the study group, the median time interval from collapse of the patient until initiation of BLS measures was 7.7 min, 7 min in C1 and 8 min in C2. ACLS measures were initiated significantly earlier (P<0.05) in the control groups, as compared to the study group [S: 13 min, C1: 11 min; C2: 10.3 min]. Sixty-seven percent (30/45) of the study patients and 46% (36/76) of the control patients were defibrillated within 12 min. Study patients were defibrillated earlier (P<0.05) (S: 9.9 min; C1: 12.2 min; C2: 12.75 min); return of spontaneous circulation (ROSC) was achieved earlier (P<0.05) in the study group [S: 14 min; C1: 19 min; C2: 18.2 min] and the number of patients in the study group requiring no epinephrine during resuscitation was higher (P<0.01) than in the control groups [S: 35.3% (12/34); C1: 10% (4/40); C2: 10.5% (4/38)]. Furthermore, the total amount of epinephrine [mean (±standard error)] administered in the study group [S: 2.35 (±0.49) mg; C1: 6.71 (±0.98) mg; C2: 7.71 (±1.31) mg] was significantly lower (P<0.05). No significant differences in neurological long-term prognosis were found for the groups investigated. Conclusion. Neither the initial survival rate the number of patients discharged alive, nor the neurological long-term prognosis was significantly different for any of the groups investigated. Because of apparent differences in indirect prognostic parameters (time interval until ROSC, number of patients requiring no epinephrine) and because of the fact that the time interval to the first defibrillation was reduced by EMT defibrillation, EMT-Ds may perform defibrillation if: (a) they reach the patient before the emergency physician and (b) if they are trained intensively and supervised continuously. In order to increase the efficiency of defibrillation by EMT-Ds, far-reaching changes in our EMS are mandatory: (a) a reduction in the time interval from collapse until initiation of BCLS measures by intensifying layperson CPR training; (b) an increase in the number of emergency units equipped with semiautomatic defibrillators; (c) the consistent implementation of a tiered EMS.

Ventilation volumes with different self-inflating bags with reference to the ERC guidelines for airway management: comparison of two compression techniques

The 1998 ERC-guidelines for airway-management recommend an tidal volume of 400-600 ml for adults undergoing CPR. As commercially available self-inflating bags were designed to meet former recommendations (800-1200 ml) we investigated how to meet the latest recommendations with these bags. We combined the head of a training manikin (Laerdal Medical) and a standard lung (VTTL; Michigan Instrument), adjusted to a physiological compliance and resistance. Volume was measured with a Wright spirometer (BOC). Seven self-inflating bags were investigated. Tests were carried out by ten people (five female and five male) for 5 min each using two different techniques. Technique 1: standard ventilation with one hand without compression of the self-inflating bag against the rescuers knee. Technique 2: modified open palm technique with total squeezing of the self-inflating bag by compression against the rescuers knee. The average tidal volumes for technique 1 ranged from 438 to 604 ml. Applying technique 2 the volumes ranged from 888 to 1192 ml. The latest recommendations were met using a single hand technique without compression against the rescuers knee for all seven bags tested. The modified open palm technique produced larger tidal volumes which were more in line with previous recommendations.