Abstract 359: Use of Resuscitative Balloon Occlusion of the Aorta in a Swine Model of Prolonged Cardiac Arrest

Introduction: Despite advancements in CPR, survival to hospital discharge remains low for in- and out-of-hospital cardiac arrest (CA). Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is an evolving tool for temporary control of non-compressible truncal hemorrhage. In this investigation, we examined whether REBOA use during non-traumatic CA would produce favorable hemodynamic changes associated with return of spontaneous circulation (ROSC). Hypothesis: We hypothesized that REBOA use during CPR would result in higher coronary perfusion pressure (CPP) and common carotid artery blood flow (C-Flow) in a prolonged model of CA. Methods: Six male swine were anesthetized and instrumented to measure and monitor CPP, and C-Flow. A REBOA catheter (Prytime Medical Devices) was advanced into zone 1 of the aorta through the femoral artery. Ventricular fibrillation was electrically induced and untreated for 8 minutes. CPR was started manually at minute-8, then changed to mechanical CPR at minute-12 for the duration of the experiment. Continuous infusion of epinephrine (0.0024mg/kg/min) was simultaneously started with mechanical CPR. The REBOA balloon was inflated beginning at minute-16 for 3 minutes then deflated for 3 minutes for a total of 6 cycles. At the end of the final cycle (REBOA inflation), CPR was stopped (after 33 minutes of total arrest time) and animals were defibrillated using 200 J biphasic shocks, repeated up to 6 times. Animals achieving ROSC were monitored for an additional 25 minutes. Results: Analysis using repeated measure ANOVA showed significant differences between balloon deflation and inflation periods for CPP (p<0.0001) with mean difference(SD) of 14(2.6) (Range: 17 to 42) mmHg and for C-Flow (p<0.0001) with mean difference(SD) 16(23) (Range: 115 to 269) mL/min across all animals. Three animals achieved ROSC and had significantly higher CPP (48 vs. 24mmHg, p<0.0001) and C-Flow (249 vs. 168mL/min) by t-test (p<0.0001). Post-mortem aortic histology did not reveal any changes produced by balloon inflation. Conclusion: REBOA significantly increased CPP and C-Flow in this swine model of prolonged CA. These increases may have contributed to the ability to achieve ROSC after greater than 30 min of CA.

Download Full-text

Abstract 358: Aortic Balloon Occlusion Augments the Efficacy of External Cardiopulmonary Resuscitation After Traumatic Cardiac Arrest in Swine

Circulation ◽

10.1161/circ.138.suppl_2.358 ◽

2018 ◽

Vol 138 (Suppl_2) ◽

Author(s):

Jiefeng Xu ◽

Peng Shen ◽

Senlin Xia ◽

Yuzhi Gao ◽

Shaoyun Liu ◽

...

Keyword(s):

Cardiac Arrest ◽

Cardiopulmonary Resuscitation ◽

Cerebral Perfusion ◽

Coronary Perfusion Pressure ◽

Balloon Occlusion ◽

Control Group ◽

Swine Model ◽

Coronary Perfusion ◽

Traumatic Cardiac Arrest ◽

Aortic Balloon Occlusion

Introduction: Following hemorrhage-induced traumatic cardiac arrest (TCA), the effectiveness of standard cardiopulmonary resuscitation (CPR) would be weakened or lost due to an inadequate circulating volume. Previous investigations demonstrated that aortic balloon occlusion (ABO) could control the bleeding and increase proximal organ perfusion during severe traumatic hemorrhage. In this study, we investigated the effect of ABO on the efficacy of CPR in a swine model of TCA. Hypothesis: ABO initiated during CPR would increase cardiac and cerebral perfusion so as to improve the outcomes of resuscitation after TCA in swine. Methods: Twenty-seven male domestic swine weighing 33±4 kg were utilized. Forty percent of estimated blood volume was removed within 20 mins. The animals were then subjected to 5 mins of untreated ventricular fibrillation and 5 mins of CPR. Coincident with the start of CPR, the animals were randomized to receive ABO (n=15) or control (n=12). Meanwhile, normal saline was intravenously infused at a speed of 0.7 ml/kg/min in all animals. Results: During CPR, significantly greater coronary perfusion pressure, regional cerebral oxygen saturation and end-tidal CO 2 were observed in animals treated with ABO when compared with the control group (Table). Consequently, the rate of resuscitation success was significantly higher in the ABO group than in the control group (15/15 vs. 9/12, p = 0.040). Additionally, shorter duration of CPR (5.1±0.5 vs. 7.5±4.5 min, p = 0.054) and less number of shocks (1.1±0.3 vs. 2.0±1.8, p = 0.058) were required for establishing spontaneous circulation in the ABO group compared to the control group. Conclusion: The implementation of ABO during CPR significantly increased cardiac and cerebral perfusion and improved the outcomes of resuscitation in TCA following massive hemorrhage.

Download Full-text

Abstract P115: Higher Threshold and Dose of Coronary Perfusion Pressure are Associated with ROSC in Prolonged Swine Cardiac Arrest

Circulation ◽

10.1161/circ.118.suppl_18.s_1470-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Joshua C Reynolds ◽

David D Salcido ◽

James J Menegazzi

Keyword(s):

Cardiac Arrest ◽

Myocardial Perfusion ◽

Regression Models ◽

Perfusion Pressure ◽

Coronary Perfusion Pressure ◽

Spontaneous Circulation ◽

Coronary Perfusion ◽

Experimental Protocol ◽

Total Flow ◽

Mechanical Cpr

Introduction: The amount of myocardial perfusion required for successful defibrillation after prolonged cardiac arrest is not known. Coronary perfusion pressure (CPP) is a surrogate for myocardial perfusion. One limited clinical study reported that a threshold of 15mmHg was necessary for return of spontaneous circulation (ROSC), and that CPP was predictive of ROSC. A distinction between threshold and dose of CPP has not been reported. Hypothesis: Animals that achieve ROSC will have higher mean CPP and higher area under the CPP curve (AUC) than no-ROSC swine. Methods: Data from 4 similar swine cardiac arrest studies were retrospectively pooled. Animals had undergone 8 –11 minutes of untreated ventricular fibrillation, 2 minutes of mechanical CPR, administration of drugs, and 3 more minutes of CPR prior to the first shock. Mean CPP ± standard error was derived from the last 20 compressions of each 30 second epoch of CPR and compared between ROSC/no-ROSC groups by RM-ANOVA. AUC for all compressions delivered over the 5 minutes was calculated by direct summation and compared by Kruskal-Wallis test. Prediction of ROSC was assessed by logistic regression. Results : During 5 minutes of CPR (n=80), mean CPP ± SEM was higher in animals with ROSC (n=63) (p < 0.001). Animals with ROSC received more total flow than animals without ROSC (p < 0.001). Two regression models identified CPP (OR 1.11; 95% CI 1.05, 1.18) and AUC (OR 1.10; 95% CI 1.05, 1.16) as predictors of ROSC. Experimental protocol also predicted ROSC in each model (OR 1.70; 95% CI 1.15, 2.50) and (OR 1.59; 95% CI 1.12, 2.25), respectively. Conclusion : Higher CPP threshold and dose are associated with and predictive of ROSC.

Download Full-text

Swine model in cardiopulmonary resuscitation research

Journal of the Hellenic Veterinary Medical Society ◽

10.12681/jhvms.14935 ◽

2017 ◽

Vol 60 (3) ◽

pp. 254

Author(s):

Th. XANTHOS (Θ. ΞΑΝΘΟΣ)

Keyword(s):

Cardiac Arrest ◽

Perfusion Pressure ◽

Coronary Perfusion Pressure ◽

Spontaneous Circulation ◽

Experimental Models ◽

Medical Emergency ◽

Swine Model ◽

Coronary Perfusion ◽

Anatomy And Physiology ◽

Experimental Treatments

Cardiac Arrest (CA) constitutes a real medical emergency. Various experimental models have been developed in order to test experimental treatments. Animal models that have been used in CA research are rodents, rabbits, cats and dogs, primates and swine. Among these, swine are used more often. The reason behind this choice is mostly its close resemblance to the human cardiac anatomy and physiology. Various haemodynamic variables have been investigated as predictors of the return of spontaneous circulation (ROSC). Coronary Perfusion Pressure (CPP) is the only proven predictor for ROSC. CPP, which is responsible for myocardial perfusion, greatly augments during chest compressions. ROSC and therefore survival after CA has been associated with CCP values greater than 15 mmHg for humans and 25 mmHg for animals. For the experimental induction of CA various electric sources have been used. All these experimental devices could be potentially dangerous for researchers, even though, no incidence of electrocution has been reported in the international literature. The ordinary cadmium battery appears to be safer and is an extremely effective way of inducing cardiac arrest.

Download Full-text

Abstract 167: Epinephrine Plus Chest Compressions May Be Superior to Epinephrine Alone in a Hypoxia-Induced Porcine Model of Lifeless Shock

Circulation ◽

10.1161/circ.140.suppl_2.167 ◽

2019 ◽

Vol 140 (Suppl_2) ◽

Author(s):

Felipe Teran ◽

Claire Centeno ◽

Alex L Lindqwister ◽

William J Hunckler ◽

William Landis ◽

...

Keyword(s):

Chest Compression ◽

Porcine Model ◽

Contractile Activity ◽

Coronary Perfusion Pressure ◽

Spontaneous Circulation ◽

Swine Model ◽

Coronary Perfusion ◽

Chest Compressions ◽

Fraction Of Inspired Oxygen ◽

External Chest Compressions

Background: Lifeless shock (LS) (previously called EMD and pseudo-PEA) is a global hypotensive ischemic state with retained coordinated myocardial contractile activity and an organized ECG. We have previously described our hypoxic LS model. The role of standard external chest compressions remains unclear in the setting of LS and its associated intrinsic hemodynamics. Although it is known the patients with LS have better prognosis compared to PEA, it is unclear what is the best treatment strategy. Prior work has shown that chest compressions (CC) when synchronized with native systole results in significant hemodynamic improvement, most notably coronary perfusion pressure (CPP), and hence it is plausible that standard dyssynchronous CC may be detrimental to hemodynamics. Furthermore, retrospective clinical data has shown that LS patients treated with vasopressors and no CC, may have better outcomes. We compared epinephrine only versus epinephrine and chest compression, in a porcine model of LS. Methods: Our porcine model of hypoxic LS has previously been described. We randomized pigs to episodes of LS treated with epinephrine only (control) (0.0015 mg/kg) versus epinephrine plus standard external chest compressions (intervention). Animals were endotracheally intubated and mechanically ventilated, and the fraction of inspired oxygen (FiO 2 ) was gradually lowered from room air (20-30% O 2 ) to a target FiO 2 of 3-7% O 2 . This target FiO 2 was maintained until the systolic blood pressure (SBP) dropped to 30 mmHg for 30 seconds, or the animal became bradycardic (HR less than 40), which was defined as the start of LS. FiO 2 was then raised to 100%, and then animal would receive control or intervention. Return of spontaneous circulation (ROSC) was defined as SBP 60 mmHg, stable after 2 minutes. Results: Twenty-six episodes of LS in 11 animals received epinephrine only control and 21 episodes the epinephrine plus chest compression intervention. The rates of ROSC in two minutes or less were 5/26 (19%) in the control arm vs 14/21 (67%) in the intervention arm (P=0.001;95% CI 19.7 %-67.2%). Conclusions: In a swine model of hypoxia induced LS, epinephrine plus CPR may be superior to epinephrine alone.

Download Full-text

Cardiac Arrest and Resuscitation

10.2310/im.4155 ◽

2015 ◽

Author(s):

Charles N. Pozner ◽

Jennifer L Martindale

Keyword(s):

Cardiac Arrest ◽

Ventricular Arrhythmias ◽

Perfusion Pressure ◽

Pulseless Electrical Activity ◽

Coronary Perfusion Pressure ◽

Spontaneous Circulation ◽

Coronary Perfusion ◽

Chest Compressions ◽

Cardiac Resuscitation ◽

Neurologic Function

The most effective treatment for cardiac arrest is the administration of high-quality chest compressions and early defibrillation; once spontaneous circulation is restored, post–cardiac arrest care is essential to support full return of neurologic function. This review summarizes the pathophysiology, stabilization and assessment, diagnosis and treatment, and disposition and outcomes of cardiac arrest and resuscitation. Figures show the foundations of cardiac resuscitation, ventricular arrhythmias, coronary perfusion pressure as a function of time, an algorithm for initial treatment of cardiac arrest, sample capnographs, and the electrocardiographic appearance of varying degrees of hyperkalemia. Tables include components of suboptimal cardiac resuscitation and corrective actions, recommended doses of medications commonly used in cardiac resuscitation, causes of pulseless electrical activity/asystolic arrest to consider, immediate post–return of spontaneous circulation checklist, and resuscitation goals during post–cardiac arrest care. This review contains 6 highly rendered figures, 5 tables, and 142 references.

Download Full-text

Comparing anesthesia with isoflurane and fentanyl/fluanisone/midazolam in a rat model of cardiac arrest

Journal of Applied Physiology ◽

10.1152/japplphysiol.00998.2015 ◽

2017 ◽

Vol 123 (4) ◽

pp. 867-875 ◽

Cited By ~ 2

Author(s):

Niels Secher ◽

Christian Lind Malte ◽

Else Tønnesen ◽

Leif Østergaard ◽

Asger Granfeldt

Keyword(s):

Cardiac Arrest ◽

Reperfusion Injury ◽

Perfusion Pressure ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Coronary Perfusion Pressure ◽

Spontaneous Circulation ◽

Coronary Perfusion ◽

Return Of Spontaneous Circulation ◽

Arterial Blood

Only one in ten patients survives cardiac arrest (CA), underscoring the need to improve CA management. Isoflurane has shown cardio- and neuroprotective effects in animal models of ischemia-reperfusion injury. Therefore, the beneficial effect of isoflurane should be tested in an experimental CA model. We hypothesize that isoflurane anesthesia improves short-term outcome following resuscitation from CA compared with a subcutaneous fentanyl/fluanisone/midazolam anesthesia. Male Sprague-Dawley rats were randomized to anesthesia with isoflurane ( n = 11) or fentanyl/fluanisone/midazolam ( n = 11). After 10 min of asphyxial CA, animals were resuscitated by mechanical chest compressions, ventilations, and epinephrine and observed for 30 min. Hemodynamics, including coronary perfusion pressure, systemic O2 consumption, and arterial blood gases, were recorded throughout the study. Plasma samples for endothelin-1 and cathecolamines were drawn before and after CA. Compared with fentanyl/fluanisone/midazolam anesthesia, isoflurane resulted in a shorter time to return of spontaneous circulation (ROSC), less use of epinephrine, increased coronary perfusion pressure during cardiopulmonary resusitation, higher mean arterial pressure post-ROSC, increased plasma levels of endothelin-1, and decreased levels of epinephrine. The choice of anesthesia did not affect ROSC rate or systemic O2 consumption. Isoflurane reduces time to ROSC, increases coronary perfusion pressure, and improves hemodynamic function, all of which are important parameters in CA models. NEW & NOTEWORTHY The preconditioning effect of volatile anesthetics in studies of ischemia-reperfusion injury has been demonstrated in several studies. This study shows the importance of anesthesia in experimental cardiac arrest studies as isoflurane raised coronary perfusion pressure during resuscitation, reduced time to return of spontaneous circulation, and increased arterial blood pressure in the post-cardiac arrest period. These effects on key outcome measures in cardiac arrest research are important in the interpretation of results from animal studies.

Download Full-text

Abstract 214: Serum VEGF Levels Are Inversely Associated with Ionized Calcium Levels During the Early Postarrest Period

Circulation ◽

10.1161/circ.130.suppl_2.214 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Scott Youngquist ◽

Atman P Shah ◽

John P Rosborough ◽

James T Niemann

Keyword(s):

Cardiac Arrest ◽

Myocardial Dysfunction ◽

Rank Correlation ◽

Inverse Correlation ◽

Serum Levels ◽

Spontaneous Circulation ◽

Balloon Occlusion ◽

Ionized Calcium ◽

Swine Model ◽

Endothelial Growth Factor

BACKGROUND: Vascular endothelial growth factor (VEGF) is a signaling peptide released in response to hypoxia that induces the influx of calcium into endothelial cells. Decreases in serum levels of ionized calcium (iCa2+) are observed following resuscitation from cardiac arrest. We hypothesized that elevations in VEGF would correlate with the decrease in iCa2+ observed in a swine model of cardiac arrest. METHODS: Thirty-five mixed breed Yorkshire swine were premedicated, intubated, and placed under general anesthesia with inhaled isoflurane and nitrous oxide. Under fluoroscopic guidance, balloon occlusion of the left anterior descending coronary artery was performed, just distal to the first septal perforator to induce ventricular fibrillation (VF). Following 7 minutes of untreated VF, standard ALS resuscitation was attempted. Upon return of spontaneous circulation, blood was sampled at 0, 15, and 30 min post arrest for levels of iCa2+ and VEGF. RESULTS: iCa2+ demonstrated an inverse correlation with VEGF levels, with a Spearman rank correlation of rho=-0.52, p<0.0001. In generalized linear mixed modeling (FIGURE 1), a 1 pg/mL increase in VEGF concentrations was associated with a decrease in iCa2+ of 0.001 mg/dL (95% CI 0.003-0.001, p<0.0001). CONCLUSIONS: VEGF is inversely associated with iCa2+ during the early post arrest period. Its production may be responsible for the observed decrease in circulating iCa2+, which may in turn contribute to post arrest hypotension and myocardial dysfunction.

Download Full-text

Resuscitative endovascular balloon occlusion of the aorta vs epinephrine in the treatment of non-traumatic cardiac arrest in swine

Annals of Intensive Care ◽

10.1186/s13613-021-00871-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alice Hutin ◽

Yaël Levy ◽

Fanny Lidouren ◽

Matthias Kohlhauer ◽

Pierre Carli ◽

...

Keyword(s):

Blood Flow ◽

Cardiac Arrest ◽

Life Support ◽

Statistical Significance ◽

Spontaneous Circulation ◽

Balloon Occlusion ◽

Swine Model ◽

Epinephrine Administration ◽

Traumatic Cardiac Arrest ◽

Endovascular Balloon Occlusion

Abstract Background The administration of epinephrine in the management of non-traumatic cardiac arrest remains recommended despite controversial effects on neurologic outcome. The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) could be an interesting alternative. The aim of this study was to compare the effects of these 2 strategies on return of spontaneous circulation (ROSC) and cerebral hemodynamics during cardiopulmonary resuscitation (CPR) in a swine model of non-traumatic cardiac arrest. Results Anesthetized pigs were instrumented and submitted to ventricular fibrillation. After 4 min of no-flow and 18 min of basic life support (BLS) using a mechanical CPR device, animals were randomly submitted to either REBOA or epinephrine administration before defibrillation attempts. Six animals were included in each experimental group (Epinephrine or REBOA). Hemodynamic parameters were similar in both groups during BLS, i.e., before randomization. After epinephrine administration or REBOA, mean arterial pressure, coronary and cerebral perfusion pressures similarly increased in both groups. However, carotid blood flow (CBF) and cerebral regional oxygenation saturation were significantly higher with REBOA as compared to epinephrine administration (+ 125% and + 40%, respectively). ROSC was obtained in 5 animals in both groups. After resuscitation, CBF remained lower in the epinephrine group as compared to REBOA, but it did not achieve statistical significance. Conclusions During CPR, REBOA is as efficient as epinephrine to facilitate ROSC. Unlike epinephrine, REBOA transitorily increases cerebral blood flow and could avoid its cerebral detrimental effects during CPR. These experimental findings suggest that the use of REBOA could be beneficial in the treatment of non-traumatic cardiac arrest.

Download Full-text

Abstract 215: Hemodynamics of Absolute, Proportional, and Adaptive Mechanical Chest Compression Strategies in a Swine Model of Pediatric Out-Of-Hospital Cardiac Arrest

Circulation ◽

10.1161/circ.140.suppl_2.215 ◽

2019 ◽

Vol 140 (Suppl_2) ◽

Author(s):

David D Salcido ◽

Allison C Koller ◽

Cornelia Genbrugge ◽

Caelie Kern ◽

James J Menegazzi

Keyword(s):

Cardiac Arrest ◽

Pressure Sensors ◽

Adaptive Strategy ◽

Coronary Perfusion Pressure ◽

Right Atrial ◽

Swine Model ◽

Coronary Perfusion ◽

Supporting Evidence ◽

Pediatric Resuscitation ◽

The Right

Background: Guidelines for pediatric resuscitation recommend a depth of 1.5in or 1/3 anterior-posterior chest diameter for chest compressions (CC) despite little supporting evidence. Objective: To evaluate the hemodynamic effects of the two recommended depths and an adaptive strategy. Methods: Thirty-eight animals (mass ~25kg) were sedated, anesthetized, intubated, and ventilated. Micromanometer pressure sensors were installed in the aorta and right atrium via the right femoral artery and vein. Coronary perfusion pressure (CPP) was calculated as aortic minus right atrial pressure. An ultrasonic flow probe was secured around the right common carotid. Biosignals were recorded at 1000Hz. Animals were then re-paralyzed, followed by a fentanyl bolus, and the endotracheal tube was occluded for 9min. Each was randomized to absolute (Group 1: 1.5in & 100/min), proportional (Group 2: 1/3 AP diameter & 100/min), or stepwise adaptive (Group 3: 1.5in & 100/min, adding 0.25in or 5/min q25s until CPP > 25mmHg) CC using a robotic compressor. Epinephrine (0.1mg/kg) and sodium bicarbonate (1mEq/kg) were given after 4min, followed by epinephrine (0.15mg/kg) q3min. Defibrillation (150J) was attempted after 5min; CPR discontinued after 20min. Mean arterial pressure (MAP), CPP and carotid blood flow (CBF) were calculated for the first 10 minutes of CPR and compared between groups with generalized estimating equations (GEE). Results: In GEE models, MAP, CBF and CPP did not differ between groups over the first 10 minutes of resuscitation. Each measure differed significantly over time (p<0.05). When considering only the first 5 minutes (early phase including first pressor), hemodynamic variables also did not differ. Conclusion: In a swine model of asphyxial cardiac arrest, CC methods based on current guidelines and an additional adaptive approach did not differ hemodynamically.

Download Full-text

Abstract 265: Deterioration of Hemodynamic Support During Prolonged Mechanical CPR in a Porcine Model of Cardiac Arrest

Circulation ◽

10.1161/circ.140.suppl_2.265 ◽

2019 ◽

Vol 140 (Suppl_2) ◽

Author(s):

Shannon E Allen ◽

Samantha Ang ◽

Cody Smith ◽

George Techiryan ◽

John M Canty ◽

...

Keyword(s):

Cardiac Arrest ◽

Near Infrared ◽

Porcine Model ◽

Aortic Pressure ◽

Coronary Perfusion Pressure ◽

Coronary Perfusion ◽

Hemodynamic Support ◽

Electrical Induction ◽

Automated Delivery ◽

Mechanical Cpr

Introduction: Although mechanical CPR devices provide automated delivery of fixed depth chest compressions, the consistency of hemodynamic support during prolonged resuscitation efforts is unclear, particularly in the absence of concomitant vasopressor treatment. In light of recent concerns regarding potentially harmful effects of epinephrine, we evaluated the hemodynamic support generated by 20 min of mechanical CPR without concurrent vasopressor administration in a porcine model of cardiac arrest (CA). Methods: Swine (n=10) were subjected to 7-8 min of CA following electrical induction of ventricular fibrillation. CPR was subsequently performed for 20 min using a mechanical compression system (LUCAS 3.1, Stryker) programmed to administer 102 compressions/min at a fixed depth of 2.1 inches. Aortic pressure (Ao), coronary perfusion pressure (CPP), and cerebral oxygen saturation (rSO 2 ; near-infrared spectroscopy) were continuously recorded. Results were compared to a separate group of swine (n=11) that received manual CPR with a compression rate of 100/min and depth necessary to achieve peak Ao of 100 mmHg. Results: Initially, mechanical CPR generated significantly higher peak Ao and CPP vs. manual CPR ( Figure ). However, by 4 min CPR, peak Ao and CPP were no longer different between groups. Both parameters continued to decline in the mechanical CPR group but remained stable in animals receiving manual CPR. Cerebral rSO 2 values fell from 57±2 % at baseline to 42±4 % during CA (p<0.01) but were not significantly improved by mechanical or manual CPR. Conclusion: The superior hemodynamic support initially offered by mechanical CPR deteriorates during prolonged CPR when pharmacologic vasopressor support is absent. These results demonstrate that a fixed compression depth does not necessarily produce consistent hemodynamic support and suggest that concomitant vasopressor administration may be necessary to sustain Ao and CPP during prolonged mechanical CPR.

Download Full-text