Interposed Abdominal Compression Research Articles

Effect of Interposed Abdominal Compression on Cardiopulmonary Resuscitation Outcomes; a Randomized Clinical Trial.

Introduction:Standard cardiopulmonary resuscitation (STD-CPR) is successful in only 10-15% of cases in emergency department (ED). This study aimed to determine the effect of interposed abdominal compression (IAC) during resuscitation on outcomes of ED cardiac arrests.Methods:In this randomized clinical trial study, non-trauma patients aged 18-85 years, patients with in-hospital cardiac arrest hospitalized in the ED were randomly assigned into two either STD-CPR or IAC-CPR group on a 1:1 basis and using computer-generated random numbers. Participants in the intervention group, received abdominal compression during the diastole phase of STD-CPR. The rate of return of spontaneous circulation (ROSC), heart rate (HR), respiratory rate (RR), arterial blood gas (ABG) indicators, and survival rate were compared between the two groups. Results:Ninety patients were enrolled (45 in each group). There were no differences between the two groups regarding age (p = 0.76), sex (p = 0.39), employment status (p = 0.62) and Charlson comorbidity scale (p = 0.46). Abdominal compression had a positive effect on heart rate (p < 0.001), mean arterial pressure (p = 0.003), arterial blood oxygen pressure (p = 0.001), and arterial blood carbon dioxide pressure (p = 0.001) as well as a negative effect on arterial blood oxygen saturation (p = 0.029) 30 minutes after resuscitation. Out of the 90 CPR cases, 8 (17.7%) cases in intervention group and 8 (17.7%) cases in control group were successful, among which all of the 8 patients in the intervention group and 5 of the patients in the control group had been discharged from hospital without any complications. Conclusion: The results showed that abdominal compression during CPR can improve resuscitation outcomes in patients with cardiac arrest. Therefore, in order to use this technique, further research is recommended.

Part 7: CPR Techniques and Devices

Part 7: CPR Techniques and Devices : 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Threatment Recommendations

Design of near-optimal waveforms for chest and abdominal compression and decompression in CPR using computer-simulated evolution

To discover design principles underlying the optimal waveforms for external chest and abdominal compression and decompression during cardiac arrest and cardiopulmonary resuscitation (CPR). A 14-compartment mathematical model of the human cardiopulmonary system is used to test successive generations of randomly mutated external compression waveforms during cardiac arrest and resuscitation. Mutated waveforms that produced superior mean perfusion pressure became parents for the next generation. Selection was based upon either systemic perfusion pressure (SPP = thoracic aortic minus right atrial pressure) or upon coronary perfusion pressure (CPP = thoracic aortic pressure minus myocardial wall pressure). After simulations of 64,414 individual CPR episodes, 40 highly evolved waveforms were characterized in terms of frequency, duty cycle, and phase. A simple, practical compression technique was then designed by combining evolved features with a constant rate of 80 min(-1) and duty cycle of 50%. All ultimate surviving waveforms included reciprocal compression and decompression of the chest and the abdomen to the maximum allowable extent. The evolved waveforms produced 1.5-3 times the mean perfusion pressure of standard CPR and greater perfusion pressure than other forms of modified CPR reported heretofore, including active compression-decompression (ACD)+ITV and interposed abdominal compression (IAC)-CPR. When SPP was maximized by evolution, the chest compression/abdominal decompression phase was near 70% of cycle time. When CPP was maximized, the abdominal compression/chest decompression phase was near 30% of cycle time. Near-maximal SPP/CPP of 60/21 mmHg (forward flow 3.8 L/min) occurred at a compromise compression frequency of 80 min(-1) and duty cycle for chest compression of 50%. Optimized waveforms for thoraco-abdominal compression and decompression include previously discovered features of active decompression and interposed abdominal compression. These waveforms can be used by manual (Lifestick-like) and mechanical (vest-like) devices to achieve short periods of near normal blood perfusion non-invasively during cardiac arrest.

Interposed abdominal compression CPR: a comprehensive evidence based review.

Interposed abdominal compression (IAC)-CPR includes all steps of standard external CPR with the addition of manual mid-abdominal compressions in counterpoint to the rhythm of chest compressions. IAC-CPR can increase blood flow during CPR about 2-fold compared with standard CPR without IAC, as shown by six of six studies in computer models and 19 of 20 studies in various animal models. The addition of IAC has clinical benefit in humans, as indicated in 10 of 12 small to medium sized clinical studies. The technique increases the frequency of immediate return of spontaneous circulation for in-hospital resuscitations from roughly 25 to 50%. Improved survival to discharge is also likely on the basis of two small in-hospital trials. Possible harm from abdominal compression is minimal on the basis of 426 humans, 151 dogs and 14 pigs that received IAC in published reports. The complexity of performing IAC is similar to that of opening the airway and is less than that of other basic life support maneuvers. The aggregate evidence suggests that IAC-CPR is a safe and effective means to increase organ perfusion and survival, when performed by professionally trained responders in a hospital and when initiated early in the resuscitation protocol. Cost and logistical considerations discourage use of IAC-CPR outside of hospitals.

Simplified meta-analysis of clinical trials in resuscitation

Objective: To present and demonstrate a new simplified method for synthesizing results of multiple clinical trials in resuscitation research. Methods: The mean difference across studies in the proportion of favorable outcomes between experimental and control groups is calculated. This difference is shown to have a t-distribution. Its significance can be ascertained with a simple t-test. The analysis can be implemented in a one-page computer spreadsheet. Results: Simplified meta-analysis provides high sensitivity and can be extended to include weighting of studies according to size or quality, comparison of subgroups of studies, tests for outliers, and calculation of the power of the meta-analysis. Sample analyses are presented for two experimental forms of cardiopulmonary resuscitation (CPR): interposed abdominal compression (IAC) CPR and active compression–decompression (ACD) CPR. Conclusions: Traditional narrative reviews, taking note of the proportion of individual studies with statistically significant results, can lead to erroneous conclusions and unnecessary delays in the clinical use of research findings. Simplified meta-analysis can provide rapid, quantitative, and accurate estimates of the amount of benefit or harm from an experimental intervention and can further empower physicians to practice evidence-based medicine.

A LTERNATIVE C ARDIOPULMONARY R ESUSCITATION D EVICES

Cardiopulmonary resuscitation (CPR) involving manual external chest compression combined with artificial respiration was first described in 1960 by Kouwenhoven et al. (Kouwenhoven W, Jude JR, Knickerbocker GG. Closed-chest cardiac massage. JAMA. 1960;173:1064-7). In the four decades since then, there have been no widely accepted alternatives for this technique. Even with the subsequent worldwide adoption of CPR and other advanced cardiac life support measures, long-term survival after prehospital cardiac arrest is still typically only 5% to 10%. The performance of CPR must therefore be improved to increase the rate of long-term survival. Currently under development are new, alternative techniques such as interposed abdominal compression (IAC), active compression- decompression (ACD), pneumatic and nonpneumatic circumferential chest compression, and minimally invasive cardiac massage. Many of these newer techniques, compared with standard manual CPR, appear to provide superior vital organ blood flow and increased blood pressure. To date, only IAC (in-hospital only) and ACD have been shown to improve long-term survival in clinical studies. Circumferential chest compression and minimally invasive cardiac massage, on the other hand, have not yet been adequately tested in large clinical trials. Despite the difficulty and expense in studying these CPR techniques, additional research is necessary to evaluate their effectiveness in improving survival after sudden cardiac arrest.

Theoretically optimal duty cycles for chest and abdominal compression during external cardiopulmonary resuscitation.

To use an electronic model of human circulation to compare the hemodynamic effects of different durations of chest compression during external CPR, both with and without interposed abdominal compression (IAC). An electrical analog model of human circulation was studied on digital computer workstations using SPICE, a general-purpose circuit simulation program. In the model the heart and blood vessels were represented as resistive-capacitive networks, pressures as voltages, blood flow as electric current, blood inertia as inductance, and cardiac and venous valves as diodes. External pressurization of the heart and great vessels, as would occur in IAC-CPR, was simulated by the alternate application of damped rectangular voltage pulses, first between intrathoracic vascular capacitances and ground, and then between intra-abdominal vascular capacitances and ground. With this model compression frequencies of 60, 80, and 100 cycles/min and duty cycles ranging from 10% to 90%, both with and without IAC, were compared. There was little difference in hemodynamics when the overall compression frequency was varied between 60 and 100 cycles/min, but the effects of duty cycle were substantial. During both standard CPR and IAC-CPR, total flow and coronary flow were greatest at chest compression durations equal to 30% of cycle time. Interposed abdominal compression substantially improved simulated systemic blood flow and perfusion pressure at all duty cycles, compared with standard CPR without abdominal compression. Mean arterial pressure > 75 mm Hg and artificial cardiac output > 2.0 L/min could be generated by 30% duty cycle compression with IAC. Coronary perfusion in the model is clearly optimized at 30% chest compression (i.e., high-impulse chest compression technique). Combined high-impulse chest compressions and IACs maximize blood flow during CPR in the electrical analog model of human circulation.

Interposed abdominal compression-CPR: Its effects on parameters of coronary perfusion in human subjects

Recent literature has emphasized the relationship between coronary perfusion during CPR and the success of resuscitation from prolonged arrest. In this study, aortic and right atrial pressures were monitored simultaneously during modifications of CPR. Three parameters associated with survival or coronary blood flow during CPR were measured: diastolic arterial pressure (DAP), diastolic arteriovenous difference (DAVD), and mean AV difference (MAVD). Standard advanced cardiac life support protocol was used although vasopressors were given by continuous infusion. In a series of two-minute trials, standard CPR, interposed abdominal compression (IAC) CPR, high-compression force (HCF) IAC-CPR, and HCF standard CPR were performed, with each patient serving as his own control. The DAP increased from 25 mm Hg during standard CPR to 43 during IAC CPR (P less than .001) and 50 during HC-IAC-CPR (P less than .001). The MAVD increased from 4 to 8 mm Hg during HCF-IAC-CPR (P less than .05). IAC-CPR had inconsistent effects on the DAVD. Three patients had a return of spontaneous circulation during the modifications of CPR after a mean of 43 minutes of asystole with standard CPR. In the seven autopsied patients, no significant abdominal injury was found. All forms of CPR studies produced DAVD in the majority of patients well below the minimum DAVD needed for resuscitation in animal models of prolonged arrest. Although the interposed abdominal compression seems to offer some advantages over standard CPR, these hemodynamic data suggest that it would be unlikely to improve survival rates appreciably.

CPR-induced trauma: Comparison of three manual methods in an experimental model

Cardiopulmonary resuscitation (CPR) often results in traumatic injury to the patient. Differences in CPR-induced trauma among various forms of manual, external CPR, however, are unknown. We compared CPR-induced trauma among manual standard (STD) CPR at 60 compressions per minute; high-impulse compression (HIC) CPR at 120 compressions per minute; and interposed abdominal compression (IAC) CPR at 60 compressions per minute. A large (24 +/- 3 kg) mongrel canine model was used. Ten animals were assigned to each type of CPR. Each received 17 minutes of CPR, applied to produce the best possible coronary perfusion pressure without obviously damaging the dog. Defibrillation was attempted at 20 minutes. Necropsy was performed at the time of death or after sacrifice at 24 hours. Careful postmortem examination of the thorax, lungs, heart, abdomen, and great vessels was performed. A semiquantitative trauma score of 0 to 5 was assigned to each area with a possible maximal score of 25. There was no difference in trauma scores among STD (6.4 +/- 1.5), HIC (9.4 +/- 1.4), and IAC (8.1 +/- 1.3) methods. No significant correlation was found between the method of CPR and the different types of trauma. Specifically, IAC did not produce an increase in liver lacerations nor did HIC produce a significant increase in thoracic or pulmonary injuries. Six of 20 initially resuscitated animals expired during the 24-hour follow-up period due to CPR-induced injuries. Four of these six had extensive pulmonary trauma, including pulmonary hemorrhage or edema. Liver lacerations were the second most lethal injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolonged cardiac arrest and resuscitation in dogs: Brain mitochondrial function with different artificial perfusion methods

Clinical techniques for artificial perfusion have not previously been examined directly for their effects on brain high-energy metabolism. Our study involved 24 large mongrel dogs that were anesthetized, instrumented for central venous intravenous access, and subjected to craniotomy to expose the dura and underlying parietal cortex. The animals were divided into the following six experimental groups of four animals each: nonischemic controls; 15-minute cardiac arrest without resuscitation; 45-minute cardiac arrest without resuscitation; 15-minute cardiac arrest plus 30 minutes resuscitation with conventional cardiopulmonary resuscitation (CPR); 15-minute cardiac arrest plus 30 minutes resuscitation with interposed abdominal compression (IAC) CPR; and 15-minute cardiac arrest plus 30 minutes resuscitation with internal cardiac massage. Cardiac arrest was induced by central venous injection of KCl 0.6 mEq/kg, and it was confirmed by continuous ECG monitoring. The three active resuscitation models included administration of NaHCO3 and epinephrine, but no attempt was made to restart the heart by defibrillation during resuscitation. At the indicated time in each group, a 4- to 5-g sample of brain was removed through the craniotomy, immediately cooled to 0 C and processed for isolation of mitochondria. The mitochondria were studied for their content of superoxide dismutase and for quantitative oxygen consumption with glutamate/malate substrate during resting and ADP-stimulated respiration. Our results show a significant drop in brain mitochondrial superoxide dismutase activity during the first 15 minutes of cardiac arrest. There is minimal injury to brain mitochondrial oxygen consumption during both 15 and 45 minutes of complete ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of interposed abdominal compression during CPR on central arterial and venous pressures

Despite the problems inherent in estimating blood flow from pressure, determination of systolic arterial pressure during cardiopulmonary resuscitation (CPR) is common and probably valuable as an indicator of potential systemic flow. The addition of interposed abdominal compression (IAC) to closed-chest CPR has been promoted because of its potential to increase systolic arterial pressure during CPR. Interposed abdominal compressions have also reportedly increased diastolic arterial-central venous pressure difference (DA-DCVP) and, thus, have the potential to increase coronary vascular flow. Two distinct methods of CPR were studied in conjunction with IAC. In six humans, there was no significant increase late in the resuscitative process in systolic arterial pressure or in DA-DCVP difference with IAC as compared with the two methods of CPR studied without IAC.