Compression-decompression Cardiopulmonary Resuscitation Research Articles

Hemodynamics, survival and neurological function with early versus delayed automated head-up CPR in a porcine model of prolonged cardiac arrest

AimTo determine if controlled head and thorax elevation, active compression-decompression cardiopulmonary resuscitation (CPR), and an impedance threshold device combined, termed automated head-up positioning CPR (AHUP-CPR), should be initiated early, as a basic (BLS) intervention, or later, as an advanced (ALS) intervention, in a severe porcine model of cardiac arrest. MethodsYorkshire pigs (n = 22) weighing ∼40 kg were anesthetized and ventilated. After 15 minutes of untreated ventricular fibrillation, pigs were randomized to AHUP-CPR for 25 minutes (BLS group) or conventional CPR for 10 minutes, followed by 15 minutes of AHUP-CPR (ALS group). Thereafter, epinephrine, amiodarone, and defibrillation were administered. Neurologic function, the primary endpoint, was assessed 24-hours later with a Neurological Deficit Score (NDS, 0 = normal and 260 = worst deficit score or death). Secondary outcomes included return of spontaneous circulation (ROSC), cumulative survival, hemodynamics and epinephrine responsivity. Data, expressed as mean ± standard deviation, were compared using Fisher's Exact, log-rank, Mann-Whitney U and unpaired t-tests. ResultsROSC was achieved in 10/11 pigs with early AHUP-CPR versus 6/11 with delayed AHUP-CPR (p = 0.14), and cumulative 24-hour survival was 45.5% versus 9.1%, respectively (p < 0.02). The NDS was 203 ± 80 with early AHUP-CPR versus 259 ± 3 with delayed AHUP-CPR (p = 0.035). ETCO2, rSO2, and responsiveness to epinephrine were significantly higher in the early versus delayed AHUP-CPR. ConclusionWhen delivered early rather than late, AHUP-CPR resulted in significantly increased hemodynamics, 24-hour survival, and improved neurological function in pigs after prolonged cardiac arrest. Based on these findings, AHUP-CPR should be considered a BLS intervention.

Evaluation of abdominal compression–decompression combined with chest compression CPR performed by a new device: Is the prognosis improved after this combination CPR technique?

IntroductionThis study was designed to compare the outcomes of standard cardiopulmonary resuscitation (STD-CPR) and combined chest compression and abdominal compression–decompression cardiopulmonary resuscitation (CO-CPR) with a new device following out-of-hospital cardiac arrest (OHCA). Moreover, we investigated whether patient prognosis improved with this combination treatment.MethodsThis trial was a single-centre, prospective, randomized trial, and a blinded assessment of the outcomes was performed. A total of 297 consecutive patients with OHCA were initially screened, and 278 were randomized to the STD-CPR group (n = 135) or the CO-CPR group (n = 143). We compared the proportions of patients who achieved a return of spontaneous circulation (ROSC), survived to hospital admission and survived to hospital discharge. In addition, we also performed the Kaplan–Meier analysis with a log-rank test at the end of the follow-up period to compare the survival curves of the two groups.ResultsThe differences were not statistically significant in the proportion of patients who achieved ROSC [31/135 (23.0%) versus 35/143 (24.5%)] and survived to hospital admission [28/135 (20.7%) versus 33/143 (23.1%)] between the CO-CPR group and STD-CPR group. However, there was a significant difference in the proportion of patients who survived to hospital discharge [16/135 (11.9%) versus 7/143 (4.9%)] between the two groups. Nine patients (6.7%) in the CO-CPR group and 2 patients (1.4%) in the STD group showed good neurological outcomes according to the cerebral performance category (CPC) scale score, and the difference was statistically significant (P = 0.003). The Kaplan–Meier curves showed that the patients in the CO-CPR group achieved better survival benefits than those in the STD-CPR group at the end of the follow-up period (log-rank P = 0.007).ConclusionCO-CPR was more beneficial than STD-CPR in terms of survival benefits in patients who have suffered out-of-hospital cardiac arrest.Trial registration Chinese Clinical Trial Registry, registered number: ChiCTR2100049581. Registered 30 July 2021- Retrospectively registered. http://www.medresman.org.cn/uc/index.aspx.

Mathematical model of modified hybrid pump mechanism for cardiopulmonary resuscitation

Background and objectiveThe “Cardiac pump theory” and “Thoracic pump theory” are representative theories of cardiopulmonary resuscitation (CPR) mechanisms. Based on these theories, many studies on mathematical modeling have been performed to help understand hemodynamics during CPR. However, there are parts that do not yet properly reflect the physiology of CPR. Therefore, this study aims to develop a lumped parameter model of CPR that can more accurately reflect the current CPR physiology. MethodsBy adding compartments of the superior and inferior vena cava of the thoracic cavity to the existing CPR model, and the “Hybrid pump” mechanism was applied to simulate CPR. To compare the hemodynamics of the conventional CPR model and the developed CPR model, various conditions, such as active compression–decompression CPR with an impedance threshold valve device (ACD–CPR+ITV), head-up-tilt (HUT), and head-down-tilt (HDT), were simulated. The coronary perfusion pressure (CPP) was compared by modulating the compression ratio of the atrium and ventricle with the thoracic pump factor. ResultsThe result for the comparison of coronary blood flow showed that the existing model is predominant in the compression phase, whereas the developed model is dominant in the relaxation phase. ACD–CPR + ITV results showed that the CPP decreased by 5 % in the existing model, and increased by about 46 % in the developed model, revealing a distinct hemodynamic difference between the two models. Likewise, as a result of comparing the hemodynamic differences of the two models according to the changes in tilt angle, the HUT showed similar trends, while the HDT showed slightly different results. The CPP varied accordingly with the ratio of the ventricular and atrial thoracic pump factor. ConclusionComparison of the hemodynamics with the existing model by simulating various conditions showed that the developed CPR model reflects the CPR physiology better. The model suggests that the hemodynamics may vary depending on the ventricle and atrium compression ratio. This study may provide an important basis for helping understand various situations and patient-specific hemodynamic characteristics during CPR through in-depth research, such as patient-specific model and parameter optimization.

Abstract 17: Controlled Progressive Elevation Maximizes Cerebral Perfusion Pressure During Head up CPR in a Swine Model of Cardiac Arrest

Background: Elevation of the head and thorax (HUP) during cardiopulmonary resuscitation (CPR) has been shown to result in a doubling of brain blood flow with higher Cerebral Perfusion Pressures (CerPP) after prolonged active compression-decompression (ACD) CPR with an impedance threshold device (ITD). However, the optimal angle and speed of elevation are unknown. Methods: In study A, in an anesthetized female 40 kg pig model of untreated ventricular fibrillation for 8 min, different HUP angles were assessed (20°, 30°, 40°) in a randomized manner each over a 5-minute periods of ACD+ITD CPR. Based upon study A results, study B was performed, wherein animals were randomized to the two following sequences: 20°, 30°, 40° or 40°, 30°, 20° using the same protocol. The primary endpoint was mean ± SD CerPP (mmHg) for both studies. Results: In study A, 18 pigs were studied. Overall, there was no optimal HUP angle: CerPP was 36 ± 19 for 20°, 42 ± 21 for 30°, and 44 ± 27 for 40° (p = 0.57). However, CerPPs were higher if 40 o HUP was performed during the last 5 minutes of the resuscitation (77 ± 17), versus 20 o HUP and 30 o HUP (44± 18, p = 0.003), suggestive of a sequence effect. To test this hypothesis, study B then enrolled additional animals to compare two elevation sequences 20°, 30°, 40° (n = 6) or 40°, 30°, 20° (n = 5). At 15 min of CPR, the CerPP for 20°, 30°, 40° group was 60 ± 17 and for 40°, 30°, 20° the CerPP was 23 ± 19 (p = 0.01). CerPPs were higher for the 20°, 30°, 40° group throughout the resuscitation (Figure 1). Coronary perfusion pressure was also significantly higher in the 20°, 30°, 40° group (50 ± 17 mmHg versus 22 ± 16 mmHg, p = 0.036) Conclusions: There did not appear to be an optimal HUP angle during ACD+ITD CPR. By contrast, there was an optimal HUP sequence (20,30,40) that resulted in significantly higher CerPP, suggesting controlled progressive elevation is important when performing HUP CPR as compared to an absolute immediate elevation of the head and thorax.

Life-Threatening and Suspicious Lesions Caused by Mechanical Cardiopulmonary Resuscitation

Chest compression devices for mechanical cardiopulmonary resuscitation (CPR) have become more common. Here, we report the case of a young woman who attempted resuscitated with LUCAS™2 after she was found unconscious at home. At autopsy, we found extensive intramuscular hemorrhages in posterior neck, between the scapulae, and in the lumbar region. Investigation of internal organs showed injuries to the lung, spleen, and kidney. The extension of the injuries gave rise to suspicion of homicide by smothering, which police investigation subsequently did not support. The pattern of injury could be attributed to automatic compression decompression CPR with LUCAS™2.The injuries may have been lethal had the patient survived. For the forensic pathologists, it is important to remain updated on developments in treatment techniques to avoid pitfalls when interpreting injury.Larger studies, prospective or retrospective, may be able to qualify the possible risks of automatic compression decompression CPR even further.

The future is now: neuroprotection during cardiopulmonary resuscitation.

Survival with favorable neurological function after cardiac arrest remains low. The purpose of this review is to identify recent advances that focus on neuroprotection during cardiopulmonary resuscitation (CPR). Multiple strategies have been shown to enhance neuroprotection during CPR. Brain perfusion during CPR is increased with therapies such as active compression decompression CPR and intrathoracic pressure regulation that improve cardiac preload and decrease intracranial pressure. Head Up CPR has been shown to decrease intracranial pressure thereby increasing cerebral perfusion pressure and cerebral blood flow. Sodium nitroprusside enhanced CPR increases cerebral perfusion, facilitates heat exchange, and improves neurologic survival in swine after cardiac arrest. Postconditioning has been administered during CPR in laboratory settings. Poloxamer 188, a membrane stabilizer, and ischemic postconditioning have been shown to improve cardiac and neural function after cardiac arrest in animal models. Postconditioning with inhaled gases protects the myocardium, with more evidence mounting for the potential for neural protection. Multiple promising neuroprotective therapies are being developed in animal models of cardiac arrest, and are in early stages of human trials. These therapies have the potential to be bundled together to improve rates of favorable neurological survival after cardiac arrest.

How do outcomes after active chest compression-decompression cardiopulmonary resuscitation (CPR) compare with those after standard compression CPR?

How do outcomes after active chest compression-decompression cardiopulmonary resuscitation (CPR) compare with those after standard compression CPR?

Standard cardiopulmonary resuscitation versus active compression-decompression cardiopulmonary resuscitation with augmentation of negative intrathoracic pressure for out-of-hospital cardiac arrest: a randomised trial

Active compression-decompression cardiopulmonary resuscitation (CPR) with decreased intrathoracic pressure in the decompression phase can lead to improved haemodynamics compared with standard CPR. We aimed to assess effectiveness and safety of this intervention on survival with favourable neurological function after out-of-hospital cardiac arrest. In our randomised trial of 46 emergency medical service agencies (serving 2·3 million people) in urban, suburban, and rural areas of the USA, we assessed outcomes for patients with out-of-hospital cardiac arrest according to Utstein guidelines. We provisionally enrolled patients to receive standard CPR or active compression-decompression CPR with augmented negative intrathoracic pressure (via an impedance-threshold device) with a computer-generated block randomisation weekly schedule in a one-to-one ratio. Adults (presumed age or age ≥18 years) who had a non-traumatic arrest of presumed cardiac cause and met initial and final selection criteria received designated CPR and were included in the final analyses. The primary endpoint was survival to hospital discharge with favourable neurological function (modified Rankin scale score of ≤3). All investigators apart from initial rescuers were masked to treatment group assignment. This trial is registered with ClinicalTrials.gov, number NCT00189423. 2470 provisionally enrolled patients were randomly allocated to treatment groups. 813 (68%) of 1201 patients assigned to the standard CPR group (controls) and 840 (66%) of 1269 assigned to intervention CPR received designated CPR and were included in the final analyses. 47 (6%) of 813 controls survived to hospital discharge with favourable neurological function compared with 75 (9%) of 840 patients in the intervention group (odds ratio 1·58, 95% CI 1·07-2·36; p=0·019]. 74 (9%) of 840 patients survived to 1 year in the intervention group compared with 48 (6%) of 813 controls (p=0·03), with equivalent cognitive skills, disability ratings, and emotional-psychological statuses in both groups. The overall major adverse event rate did not differ between groups, but more patients had pulmonary oedema in the intervention group (94 [11%] of 840) than did controls (62 [7%] of 813; p=0·015). On the basis of our findings showing increased effectiveness and generalisability of the study intervention, active compression-decompression CPR with augmentation of negative intrathoracic pressure should be considered as an alternative to standard CPR to increase long-term survival after cardiac arrest. US National Institutes of Health grant R44-HL065851-03, Advanced Circulatory Systems.

Shock outcome prediction before and after CPR: A comparative study of manual and automated active compression–decompression CPR

We report on a study designed to compare the relative efficacy of manual CPR (M-CPR) and automated mechanical CPR (ACD-CPR) provided by an active compression-decompression (ACD) device. The ECG signals of out-of-hospital cardiac arrest patients of cardiac aetiology were analysed just prior to, and immediately after, cardiopulmonary resuscitation (CPR) to assess the likelihood of successful defibrillation at these time points. The cardioversion outcome prediction (COP) measure previously developed by our group was used to quantify the probability of return of spontaneous circulation (ROSC) after counter-shock and was used as a measure of the efficacy of CPR. An initial validation study using COP to predict shock outcome from the patient data set resulted in a performance of 60% specificity achieved at 100% sensitivity on a blind test of the data. This is comparable with previous studies and provided confidence in the robustness of the technique across hardware platforms. Significantly, the COP marker also displayed an ability to stratify according to outcomes: asystole, ventricular fibrillation (VF), pulseless electrical activity (PEA), normal sinus rhythm (NSR). We then used the validated COP marker to analyse the ECG data record just prior to and immediately after the chest compression segments. This was initially performed for 87 CPR segments where VF was both the pre- and post-CPR waveform. An increase in the mean COP values was found for both CPR types. A signed rank sum test found the increase due to manual CPR not to be significant (p>0.05) whereas the automated CPR was found to be significant (p<0.05). This increase was larger for the automated CPR (1.26, p=0.024) than for the manual CPR (0.99, p=0.124). These results indicate that the application of CPR does indeed provide beneficial preparation of the heart prior to defibrillation therapy whether manual or automated CPR is applied. The COP marker shows promise as a definitive, quantitative determinant of the immediate positive effect of both types of CPR regardless of the details of use. In work of a more exploratory nature we then used the validated COP marker to analyse the ECG pre- and post-CPR for all rhythm types (212 traces). We show a significant increase in the COP measure (p<0.001 in both cases) as indicated by a shift in the median COP marker distribution values. This increase was more pronounced for automated ACD-CPR than for manual CPR. However, a detailed statistical analysis carried out between the groups adjusted for pre-CPR value showed no significant difference between the two methods of CPR (p=0.20). Similarly, adjusting for length of CPR showed no significant difference between the groups. Secondary, subgroup analysis of the ECG according to the length of time for which CPR was performed showed that both types of CPR led to an increase in the likelihood of successful defibrillation after increasing durations of CPR, however results were less reliable after longer periods of continuous CPR.

Mechanical advances in cardiopulmonary resuscitation.

Challenged by the continued high mortality rates for patients in cardiac arrest, the American Heart Association and the European Resuscitation Council developed a new set of guidelines in 2000 to help advance several new and promising cardiopulmonary resuscitation (CPR) techniques and devices. This is the first time these organizations have taken such a bold move, in part because of the poor results with standard closed-chest cardiac massage. The new techniques, interposed abdominal counterpulsation and active compression decompression CPR, each provide greater blood flow to the vital organs in animal models of CPR and lead to higher blood pressures in patients in cardiac arrest. In some clinical studies, both techniques have resulted in a significant increase in survival after cardiac arrest in comparison with standard CPR. Three of the four new CPR devices that were recommended in the new guidelines also provide superior vital organ blood flow and increased blood pressures in comparison with standard CPR. The three devices that improve the efficiency of CPR are the circumferential vest, an active compression decompression CPR device, and an inspiratory impedance valve used in combination with the active compression decompression CPR device. The fourth device type, one that compresses the thorax using an automated mechanical piston compression mechanism, was recommended to reduce the number of personnel required to perform CPR. However, no studies on the automated mechanical compression devices have showed an improvement in hemodynamic variables or survival in comparison with standard CPR. Taken together, these new technologies represent an important step forward in the evolution of CPR from a pair of hands to devices designed to enhance CPR efficiency. Each of these advances is described, and the recent literature about each of them is reviewed.

Active compression—decompression versus standard cardiopulmonary resuscitation in a porcine model: No improvement in outcome

Active compression—decompression cardiopulmonary resuscitation (CPR) is a new innovative basic life-support technique during which the anterior chest wall is actively decompressed by a suction device. CPR techniques were studied in 36 swine to test the hypothesis that active compression—decompression CPR improves coronary perfusion pressure, myocardial blood flow during CPR, and 24-hour survival. After 30 seconds of untreated ventricular fibrillation, CPR was begun and continued for 12.5 minutes by one of the three following methods: (1) active compression—decompression CPR with a suction device modified to include a precision force transducer; (2) standard CPR performed with a force transducer device; and (3) standard manual CPR performed without a force transducer device. CPR-generated coronary perfusion pressure, myocardial blood flow, and the force of compression were measured at 3 and 10 minutes of resuscitation effort. Initial return of spontaneous circulation, 24-hour survival, and trauma scores were also evaluated. Active compression—decompression CPR produced consistently better results than did standard CPR performed with a force transducer, but not better than standard CPR performed manually without a force transducer. The use of a force-measuring device with standard CPR may compromise hemodynamic response and outcome.

A Randomized Clinical Trial of Active Compression-Decompression CPR vs Standard CPR in Out-of-Hospital Cardiac Arrest in Two Cities

Objective. —To compare the effectiveness of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) with a handheld suction device vs standard manual CPR in victims of out-of-hospital cardiopulmonary arrest. Design. —Prospective randomized clinical trial with crossover group design. Setting. —Emergency medical services (EMS) of a large (San Francisco) and medium-sized (Fresno) city in California. Patients. —All normothermic adult victims of out-of-hospital, nontraumatic cardiac arrest on whom CPR was performed by first responders. Intervention. —Patients were randomized to receive either standard manual CPR according to American Heart Association guidelines or ACD CPR, on first-responder contact. Main Outcome Measures. —Return of spontaneous circulation, admission to the intensive care unit, survival to hospital discharge, and neurological function at hospital discharge. Results. —The ACD group (n=117 in Fresno; n=297 in San Francisco) and standard group (n=136 in Fresno; n=310 in San Francisco) were similar with regard to demographic and prognostic variables, such as age, witnessed arrest and bystander CPR frequency, and initial cardiac rhythm. Average interval from 911 call activation to EMS responder arrival was 6.4 minutes in Fresno and 4.0 minutes in San Francisco. In Fresno, there was no difference between the ACD group and standard CPR group in return of spontaneous circulation (17% vs 20%; P =.68), hospital admission (16% vs 20%; P =.56), hospital discharge (5% vs 7%; P =.64), or cerebral performance category score at discharge (1.5 vs 1.6; P =.90). Similarly, in San Francisco there was no difference between the ACD group and standard CPR group in return of spontaneous circulation (19% vs 21%; P =.65), hospital admission (13.5% vs 14.5%; P =.79), hospital discharge (4.7% vs 5.5%; P =.80), or cerebral performance category score at discharge (2.2 vs 2.6; P =.31). There was no increase in significant complications associated with the use of ACD CPR. Conclusion. —There was no improvement in outcome with ACD CPR in out-of-hospital cardiac arrest in these two cities. Differences in study design, demographics, EMS systems, response intervals, training, and technique performance may contribute to the lack of improvement in initial resuscitation with ACD CPR compared with previous studies. Future research needs to control these variables to determine the reason for these differences in outcome. ( JAMA . 1995;273:1261-1268)

ACTIVE COMPRESSION-DECOMPRESSION CPR: IMPACT UNPROVEN.

Active compression-decompression (ACD) cardiopulmonary resuscitation uses a toilet-plunger-like device to augment the efficacy of chest compressions. Some studies suggest that ACD improves outcome in patients with cardiac arrest. This prospective study compared outcomes in 860 patients …

Compression-Decompression CPR: The Biomotor

To the Editor. —An Editorial 1 in JAMA discusses the premature termination by the Food and Drug Administration (FDA) of trials of compression-decompression cardiopulmonary resuscitation (CPR), because of lack of informed consent. The addition of a suction phase to conventional CPR is a trivial, innocuous detail that should not require consent. The developers of the Ambu 2 device must certainly have tried its suction on willing volunteers and shown that its worst effect might be minor ecchymoses. In any case, the use of alternate pressure and suction for CPR is described in the August 5,1939, Wiener Medizinische Wochenschrift by Dr Rudolph Eisenmenger, Facharzt fur physikalische Therapie, Vienna, Austria. His device, which he called a Biomotor, was a cuirass ventilator that applied alternate positive and negative air pressure to the torso, and was used extensively throughout Europe for mine rescue and other victims of asphyxia as well as polio. He urged

Active Compression-Decompression CPR

To the Editor. —Dr Lurie and colleagues 1 conclude that active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) appears to be more effective than standard CPR in certain subsets under study. This statistical inference is dependent on matching baseline characteristics as presented in their Table 1. In prehospital nontraumatic cardiac arrest, a sudden reversible cardiac miscue based on myocardial ischemia or a small myocardial infarction in an otherwise healthy person is the most likely condition to have a successful CPR outcome. On the other hand, if the pathway to arrest is pulmonary embolus, massive cerebral vascular accident, aortic dissection, or sepsis, then the probability of a successful outcome is much less. The authors match the previous cardiac history in both groups (62%); however, previous cardiac history alone, without the present clinical history, is not sufficient to give meaning to the statistical analysis. This is particularly true for the subgroup analysis of those

A Comparison of Active Compression-Decompression Cardiopulmonary Resuscitation with Standard Cardiopulmonary Resuscitation for Cardiac Arrests Occurring in the Hospital

Recent studies have demonstrated improved cardiopulmonary circulation during cardiac arrest with the use of a hand-held suction device (Ambu CardioPump) to perform active compression-decompression cardiopulmonary resuscitation (CPR). The purpose of this study was to compare active compression-decompression with standard CPR during cardiac arrests in hospitalized patients. All patients over the age of 18 years who had a witnessed cardiac arrest while hospitalized at our center were enrolled in this trial; they were randomly assigned according to their medical-record numbers to receive either active compression-decompression or standard CPR. The study end points were the rates of initial resuscitation, survival at 24 hours, hospital discharge, and neurologic outcome. Compressions were performed according to the recommendations of the American Heart Association (80 to 100 compressions per minute; depth of compression, 3.8 to 5.1 cm [1.5 to 2 in.]; and 50 percent of the cycle spent in compression). Sixty-two patients (45 men and 17 women) with a mean age (+/- SE) of 68 +/- 2 years were entered into the trial. Sixty-two percent of the patients who underwent active compression-decompression were initially resuscitated, as compared with 30 percent of the patients who received standard CPR (P < 0.03); 45 percent of the patients who underwent active compression-decompression survived for at least 24 hours, as compared with 9 percent of patients who underwent standard CPR (P < 0.004). Two of the 62 study patients survived to hospital discharge; both were randomly assigned to receive active compression-decompression. Neurologic outcome, as measured by the Glasgow coma score, was better with active compression-decompression (8.0 +/- 1.3) than with standard CPR (3.5 +/- 0.3; P < 0.02). In this preliminary study, we found that, as compared with standard CPR, active compression-decompression CPR improved the rate of initial resuscitation, survival at 24 hours, and neurologic outcome after in-hospital cardiac arrest. Larger trials will be required to assess the potential benefit in terms of long-term survival.