Mild (34 °C) versus moderate hypothermia (24 °C) in a swine model of extracorporeal cardiopulmonary resuscitation.

Background: The role of hypothermia in post-arrest neuroprotection is controversial. Animal studies suggest potential benefits with lower temperatures, but high-fidelity ECPR models evaluating temperatures below 30 °C are lacking. Objectives: To determine whether rapid cooling to 24 °C initiated upon reperfusion reduces brain injury compared to 34 °C in a swine model of ECPR. Methods: Twenty-four female pigs had electrically induced VF and mechanical CPR for 30 min. Animals were cannulated for VA-ECMO and cooled to either 34 °C for 4 h (n = 8), 24 °C for 1 h with rewarming to 34 °C over 3 h (n = 7), or 24 °C for 4 h without rewarming (n = 9). Cooling was initiated upon VA-ECMO reperfusion by circulating ice water through the oxygenator. Brain temperature and cerebral and systemic hemodynamics were continuously monitored. After four hours on VA-ECMO, brain tissue was obtained for examination. Results: Target brain temperature was achieved within 30 min of reperfusion (p = 0.74). Carotid blood flow was higher in the 24 °C without rewarming group throughout the VA-ECMO period compared to 34 °C and 24 °C with rewarming (p < 0.001). Vasopressin requirement was higher in animals treated with 24 °C without rewarming (p = 0.07). Compared to 34 °C, animals treated with 24 °C with rewarming were less coagulopathic and had less immunohistochemistry-detected neurologic injury. There were no differences in global brain injury score. Conclusions: Despite improvement in carotid blood flow and immunohistochemistry detected neurologic injury, reperfusion at 24 °C with or without rewarming did not reduce early global brain injury compared to 34 °C in a swine model of ECPR.

Controlled automated reperfusion of the whole body after cardiac arrest: Device profile of the CARL system.

BACKGROUND: Cardiac arrest is associated with high mortality rates and severe neurological impairments. One of the underlying mechanisms is global ischemia-reperfusion injury of the body, particularly the brain. Strategies to mitigate this may thus improve favorable neurological outcomes. The use of extracorporeal cardiopulmonary membrane oxygenation (ECMO) during CA has been shown to improve survival, but available systems are vastly unable to deliver goal-oriented resuscitation to control patient's individual physical and chemical needs during reperfusion. Recently, controlled automated reperfusion of the whoLe body (CARL), a pulsatile ECMO with arterial blood-gas analysis, has been introduced to deliver goal-directed reperfusion therapy during the post-arrest phase. METHODS: This review focuses on the device profile and use of CARL. Specifically, we reviewed the published literature to summarize data regarding its technical features and potential benefits in ECPR. RESULTS: Peri-arrest, mitigating severe IRI with ECMO, might be the next step toward augmenting survival rates and neurological recovery. To this end, CARL is a promising extracorporeal oxygenation device that improves the early reperfusion phase after resuscitation.

The cerebral and cardiac effects of Norepinephrine in an experimental cardiac arrest model.

Introduction: Epinephrine has been the main drug recommended for decades during cardiopulmonary resuscitation (CPR). But epinephrine's ß-adrenergic effects might increase myocardial oxygen consumption and may cause arrythmias after ROSC. Norepinephrine has a weaker ß-adrenergic effect and could be useful during CPR. Studies on norepinephrine's effect on hemodynamic parameters and cerebral perfusion are scarce. This study aimed to assess norepinephrine's hemodynamic impact in an experimental model of cardiac arrest. Methods: After an initial dose study to determine the optimal dose, we conducted a prospective randomized study with 19 pigs. After 3 minutes of untreated ventricular fibrillation, animals received boluses of 0.5 mg Epinephrine (EPI) or 1 mg Norepinephrine (NE) every 5 minutes during CPR. Coronary perfusion pressure (CPP), carotid blood flow (CBF) and cerebral perfusion pressure (CePP) were evaluated. Results: At baseline, hemodynamic parameters did not differ between the two groups. During CPR, CPP and CBF were similar: 17.3 (12.8; 31.8) in the EPI group vs 16.0 (11.1; 37.7) in the NE group, p = 0.9 and 28.4 (22.0; 54.8) vs 30.8 (12.2; 56.3) respectively, p = 0.9. CePP was not significantly lower during resuscitation in the NE group compared to the EPI group: 12.2 (-8.2; 42.2) vs 7.8 (-2.0; 32.0) p = 0.4. Survival rate was low with only one animal in the EPI group and 2 in the NE group. Conclusion: Cerebral perfusion pressure, coronary perfusion pressure and carotid blood flow during CPR did not significantly differ between the norepinephrine group and the epinephrine group. Further investigations should evaluate different options such as a continuous NE infusion.

Extracorporeal cardiopulmonary resuscitation for in- and out-of-hospital cardiac arrest: The race against time.

Objectives: Extracorporeal cardiopulmonary resuscitation (ECPR) is increasingly used due to its beneficial outcomes and results compared to conventional CPR. Cardiac arrests can be categorized depending on location: in-hospital cardiac arrest (IHCA) and out-of-hospital cardiac arrest (OHCA). Despite this distinction, studies comparing the two are scarce, especially in comparing outcomes after ECPR. This study compared patient characteristics, cardiac arrest characteristics, and outcomes. Methods: Between 2016 and 2022, patients who underwent ECPR for cardiac arrest at our institution were retrospectively analyzed, depending on the arrest location: IHCA and OHCA. We compared periprocedural characteristics and used multinomial regression analysis to indicate parameters contributing to a favorable outcome. Results: A total of n = 157 patients (100%) were analyzed (OHCA = 91; IHCA = 66). Upon admission, OHCA patients were younger (53.2 ± 12.4 vs. 59.2 ± 12.6 years) and predominantly male (91.1% vs. 66.7%, p=<0.001). The low-flow time was significantly shorter in IHCA patients (41.1 ± 27.4 mins) compared to OHCA (63.6 ± 25.1 mins). Despite this significant difference, in-hospital mortality was not significantly different in both groups (IHCA = 72.7% vs. OHCA = 76.9%, p = 0.31). Both groups' survival-to-discharge factors were CPR duration, low flow time, and lactate values upon ECMO initiation. Conclusion: Survival-to-discharge for ECPR in IHCA and OHCA was around 25%, and there was no statistically significant difference between the two cohorts. Factors predicting survival were lower lactate levels before cannulation and lower low-flow time. As such, OHCA patients seem to tolerate longer low-flow times and thus metabolic impairments compared to IHCA patients and may be considered for ECMO cannulation on a broader time span than IHCA.

Association between cardiopulmonary resuscitation duration and survival after out-of-hospital cardiac arrest according: a first nationwide study in France.

OBJECTIVE: Determining whether to pursue or terminate resuscitation efforts remains one of the biggest challenges of cardiopulmonary resuscitation (CPR). No ideal cut-off duration has been recommended and the association between CPR duration and survival is still unclear for out-of-hospital cardiac arrest (OHCA). The aim of this study was to assess the association between CPR duration and 30-day survival after OHCA with favorable neurological outcomes according to initial rhythm. METHODS: This was an observational, retrospective analysis of the French national multicentric registry on cardiac arrest, RéAC. The primary endpoint was neurologically intact 30-day survival according to initial rhythm. RESULTS: 20,628 patients were included. For non-shockable rhythms, the dynamic probability of 30-day survival with a Cerebral Performance Category (CPC) of 1 or 2 was less than 1% after 25 min of CPR. CPR duration over 10 min was not associated with 30-day survival with CPC of 1 or 2 (adjusted OR: 1.67; CI 95% 0.95-2.94). For shockable rhythms, the dynamic probability of 30-day survival with a CPC score of 1 or 2, was less than 1% after 54 min of CPR. CPR duration of 21-25 min was still associated with 30-day survival and 30-day survival with a CPC of 1 or 2 (adjusted OR: 2.77; CI 95% 2.16-3.57 and adjusted OR: 1.82; CI 95% 1.06-3.13, respectively). CONCLUSIONS: Survival decreased rapidly with increasing CPR duration, especially for non-shockable rhythms. Pursuing CPR after 25 min may be futile for patients presenting a non-shockable rhythm. On the other hand, shockable rhythms might benefit from prolonged CPR.

Cerebral hemodynamic effects of head-up CPR in a porcine model.

AIM: To assess the hemodynamic effects of head elevation on cerebral perfusion during cardiopulmonary resuscitation (CPR) in a porcine model of cardiac arrest. METHODS: VF was induced in eight 65 kg pigs that were treated with CPR after five minutes of no flow. Mean arterial pressure (MAP) was measured at the descending thoracic aorta. Internal carotid artery blood flow (CBF) was measured with an ultrasound probe. Cerebral perfusion pressure (CerPP) was calculated in two ways (CerPPICAP and CerPPreported) using the same intracranial pressure (ICP) measurement. CePPreported was calculated as MAP-ICP. CerPPICAP was calculated by using intracranial arterial pressure (ICAP) - ICP. The animals were switched between head up (HUP) and supine (SUP) CPR every five minutes for a total of twenty minutes of resuscitation. RESULTS: MAP and coronary perfusion pressure measurements were similar in both CPR positions (p = 0.36 and p = 0.1, respectively). ICP was significantly lower in the HUP CPR group (14.7 ± 1 mm Hg vs 26.9 ± 1 mm Hg, p < 0.001) as was ICAP (30.1 ± 2 mm Hg vs 42.6 ± 1 mmHg, p < 0.001). The proportional decrease in ICP and ICAP resulted in similar CerPPICAP comparing HUP and SUPCPR (p = 0.7). CBF was significantly lower during HUPCPR when compared to SUPCPR (58.5 ± 3 ml/min vs 78 ± 4 ml/min, p < 0.001). A higher CerPPreported was found during the HUP compared to SUP-CPR, when MAP was used (36.6 ± 2 mm Hg vs 23 ± 2 mm Hg, p < 0.001) without correcting for the hydrostatic pressure drop. CONCLUSION: HUP did not affect cerebral perfusion pressure and it significantly decreased internal carotid blood flow.

Case Report: Correlation between pulmonary capillary wedge pressure and left-ventricular diastolic pressure during treatment with veno-arterial extracorporeal membrane oxygenation.

Background: Pulmonary capillary wedge pressure (PCWP) is often used as a surrogate for left-ventricular end-diastolic pressure in patients (LVEDP) who are on veno-arterial extracorporeal membrane oxygenation (V-A ECMO) support for cardiogenic shock and cardiac arrest. However, the correlation between PCWP and LVEDP is not clear in the setting of V-A ECMO usage. We sought to evaluate this correlation in this case series. Methods: Patients were referred to our cardiac catheterization laboratory for invasive hemodynamic studies to assess their readiness for VA-ECMO decannulation. All patients underwent simultaneous left and right heart catheterization. Using standard techniques, we measured PCWP and LVEDP simultaneously. Continuous variables were reported as medians with interquartile ranges. The correlation between PCWP and LVEDP was evaluated using simple linear regression and reported as R2. Results: Four patients underwent invasive hemodynamic studies 4 (2.5, 7) days after VA-ECMO cannulation. All four patients had suffered in-hospital cardiac arrest and had been put on VA-ECMO. At the baseline level of VA-ECMO flow of 4.1 (3.8, 4.4) L/min, the median LVEDP and PCWP were 6 (4, 7.5) mmHg and 12 (6.5, 16) mmHg, respectively. At the lowest level of VA-ECMO flow of 1.9 (1.6, 2.0) L/min, the median LVEDP and PCWP was 13.5 (8.5, 16) mmHg and 15 (13, 18) mmHg, respectively. There was a poor correlation between the simultaneously measured PCWP and LVEDP (R2 = 0.03, p = 0.66). Conclusions: The PCWP may not correlate well with LVEDP in patients treated with VA-ECMO, particularly at high levels of VA-ECMO support.

The Minnesota first-responder AED project: Aiming to increase survival in out-of-hospital cardiac arrest.

There are 350,000 out-of-hospital cardiac arrest (OHCA) cases annually in the United States of America. Using automated external defibrillators (AEDs) has increased survival in cardiac arrests (CA) with an initial shockable rhythm. Thus, guidelines recommend complete geographical coverage with AEDs. To fill in the gaps in Minnesota, the Center for Resuscitation Medicine at the University of Minnesota raised an $18.8 million grant from the Helmsley Charitable Trust to supply law enforcement first responders with AEDs and, thus, increase survival rates after OHCA by reducing the time to first shock. This report elaborates on the decision-making, fundraising, and logistic strategy required to reach statewide AED coverage. Methods: The baseline need for AEDs was analyzed using a questionnaire sent out to state law enforcement agencies, state patrols, city and county agencies, and tribal agencies in 2021. Furthermore, OHCA cases of 2021 were reviewed. The combination of this information led to an action plan to equip and train all agencies throughout the state's eight regions with AEDs. Results: The electronic survey was initially sent out to 358 agencies. The initial response rate was 77% (n = 276). This resulted in a total need of 8300 AEDs to be deployed over three years (2022-2025). As of 2023, over 4769 AEDs have been distributed, covering 237 sites. Conclusion: By equipping first responders with AED systems, the Center for Resuscitation Medicine aims to shorten the gap in statewide AED coverage, thus increasing the chances of survival after OHCA.

Left rib fractures during cardiopulmonary resuscitation are associated with hemodynamic variations in a pig model of cardiac arrest.

Background: Chest compressions (CC) are the cornerstone of cardiopulmonary resuscitation (CPR). But CC are also known to cause injuries, specifically rib fractures. The effects of such fractures have not been examined yet. This study aimed to investigate hemodynamic effects of rib fractures during mechanical CPR in a porcine model of cardiac arrest (CA). Methods: We conducted a retrospective hemodynamic study in 31 pigs that underwent mechanical CC. Animals were divided into three groups based on the location of rib fractures: No Broken Ribs group (n = 11), Left Broken Ribs group (n = 13), and Right Broken Ribs group (n = 7). Hemodynamic measurements were taken at 10 seconds before and 10, 30, and 60 seconds after rib fractures. Results: Baseline hemodynamic parameters did not differ between the three groups. Systolic aortic pressure was overall higher in the Left Broken Ribs group than in the No Broken Ribs group at 10, 30, and 60 seconds after rib fracture (p = 0.02, 0.01, and 0.006, respectively). The Left Broken Ribs group had a significantly higher right atrial pressure compared to the No Broken Rib group after rib fracture (p = 0.02, 0.01, and 0.03, respectively). There was no significant difference for any parameter for the Right Broken Ribs group, when compared to the No Broken Ribs group. Conclusion: An increase in main hemodynamic parameters was observed after left rib fractures while right broken ribs were not associated with any change in hemodynamic parameters. Reporting fractures and their location seems worthwhile for future experimental studies.

Long-term outcomes after minimal right lateral thoracotomy for the resection of cardiac tumors.

OBJECTIVES: Cardiac tumors are a rare and heterogeneous entity, with a cumulative incidence of up to 0.02%. This study aimed to investigate one of the largest patient cohorts for long-term outcomes after minimally-invasive cardiac surgery using right-anterior thoracotomy and femoral cardiopulmonary bypass (CPB) cannulation. METHODS: Between 2009 and 2021, patients who underwent minimally-invasive cardiac tumor removal at our department were included. The diagnosis was confirmed postoperatively by (immune-) histopathological analysis. Preoperative baseline characteristics, intraoperative data, and long-term survival were analyzed. RESULTS: Between 2009 and 2021, 183 consecutive patients underwent surgery for a cardiac tumor at our department. Of these, n = 74 (40%) were operated on using a minimally-invasive approach. The majority, n = 73 (98.6%), had a benign cardiac tumor, and 1 (1.4%) had a malignant cardiac tumor. The mean age was 60 ± 14 years, and n = 45 (61%) of patients were female. The largest group of tumors was myxoma (n = 62; 84%). Tumors were predominantly located in the left atrium in 89% (n = 66). CPB-time was 97 ± 36min and aortic cross-clamp time 43 ± 24 min s. The mean hospital stay was 9.7 ± 4.5 days. The perioperative mortality was 0%, and all-cause mortality after ten years was 4.1%. CONCLUSION: Minimally-invasive tumor excision is feasible and safe, predominantly in benign cardiac tumors, even in combination with concurrent procedures. Patients who require cardiac tumor removal should be evaluated for minimally-invasive cardiac surgery at a specialized center, as it is highly effective and associated with good long-term survival.

The impact of BMI on arrest characteristics and survival of patients with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation.

AIM: To assess the impact of body mass index (BMI) on survival to hospital discharge of patients presenting with refractory ventricular fibrillation treated with extracorporeal cardiopulmonary resuscitation. We hypothesize that due to limitations in pre-hospital care delivery, people with high BMI have worse survival after prolonged resuscitation and ECPR. METHODS: This study is a retrospective single-centre study that included patients suffering refractory VT/VF OHCA from December 2015 to October 2021 and had a BMI calculated at hospital admission. We compared the baseline characteristics and survival between patients with obesity (>30 kg/m2) and those without (≤30 kg/m2). RESULTS: Two-hundred eighty-three patients were included in this study, and two-hundred twenty-four required mechanical support with veno-arterial extracorporeal cardiopulmonary membrane oxygenation (VA ECMO). Patients with BMI > 30 (n = 133) had significantly prolonged CPR duration compared to their peers with BMI ≤ 30 kg/m2 (n = 150) and were significantly more likely to require support with VA ECMO (85.7% vs 73.3%, p = 0.015). Survival to hospital discharge was significantly higher in patients with BMI ≤ 30 kg/m2 (48% vs. 29.3%, p < 0.001). BMI was an independent predictor of mortality in a multivariable logistic regression analysis. The four-year mortality rate was low and not significantly different between the two groups (p = 0.32). CONCLUSION: ECPR yields clinically meaningful long-term survival in patients with BMI > 30 kg/m2. However, the resuscitation time is significantly prolonged, and the overall survival significantly lower compared to patients with BMI ≤ 30 kg/m2. ECPR should, therefore, not be withheld for this population, but faster transport to an ECMO capable centre is mandated to improve survival to hospital discharge.

The impact of levosimendan on survival and weaning from ECMO after extracorporeal cardiopulmonary resuscitation.

OBJECTIVES: Extracorporeal cardiopulmonary resuscitation (eCPR) is increasingly used due to its beneficial outcomes and results compared to conventional CPR. After cardiac arrest, the overall ejection fraction is severely impaired; thus, weaning from ECMO is often prolonged or impossible. We hypothesized that early application of levosimendan in these patients facilitates ECMO weaning and survival. METHODS: From 2016 until 2020, patients who underwent eCPR after cardiac arrest at our institution were analyzed retrospectively and divided into two groups: patients who received levosimendan during ICU stay (n = 24) and those who did not receive levosimendan (n = 84) and analyzed for outcome parameters. Furthermore, we used propensity-score matching and multinomial regression analysis to show the effect of levosimendan on outcome parameters. RESULTS: Overall, in-hospital mortality was significantly lower in the group which received levosimendan (28% vs. 88%, p ≤ 0.01), and ECMO weaning was more feasible in patients who received levosimendan (88% vs. 20%, p ≤ 0.01). CPR duration until ECMO cannulation was significantly shorter in the levosimendan group (44 + 26 vs. 65 + 28, p = 0.002); interestingly, the rate of mechanical chest compressions before ECMO cannulation was lower in the levosimendan group (50% vs. 69%, p = 0.005). CONCLUSION: In patients after cardiac arrest treated with eCPR, levosimendan seems to contribute to higher success rates of ECMO weaning, potentially due to a short to mid-term increase in inotropy. Also, the survival after levosimendan application was higher than patients who did not receive levosimendan.

A Narrative Review of Drug Therapy in Adult and Pediatric Cardiac Arrest.

Drugs are used during cardiopulmonary resuscitation (CPR) in association with chest compressions and ventilation. The main purpose of drugs during resuscitation is either to improve coronary perfusion pressure and myocardial perfusion in order to achieve return of spontaneous circulation (ROSC). The aim of this up-to-date review is to provide an overview of the main drugs used during cardiac arrest (CA), highlighting their historical context, pharmacology, and the data to support them. Epinephrine remains the only recommended vasopressor. Regardless of the controversy about optimal dosage and interval between doses in recent papers, epinephrine should be administered as early as possible to be the most effective in non-shockable rhythms. Despite inconsistent survival outcomes, amiodarone and lidocaine are the only two recommended antiarrhythmics to treat shockable rhythms after defibrillation. Beta-blockers have also been recently evaluated as antiarrhythmic drugs and show promising results but further evaluation is needed. Calcium, sodium bicarbonate, and magnesium are still widely used during resuscitation but have shown no benefit. Available data may even suggest a harmful effect and they are no longer recommended during routine CPR. In experimental studies, sodium nitroprusside showed an increase in survival and favorable neurological outcome when combined with enhanced CPR, but as of today, no clinical data is available. Finally, we review drug administration in pediatric CA. Epinephrine is recommended in pediatric CA and, although they have not shown any improvement in survival or neurological outcome, antiarrhythmic drugs have a 2b recommendation in the current guidelines for shockable rhythms.

Effect of adrenaline dose on neurological outcome in out-of-hospital cardiac arrest: a nationwide propensity score analysis.

BACKGROUND: Adrenaline is recommended during cardio-pulmonary resuscitation. The optimal dose remains debated, and the effect of lower than recommended dose is unknown. OBJECTIVE: To compare the outcome of patients treated with the recommended, lower or higher cumulative doses of adrenaline. DESIGN, SETTINGS, PARTICIPANTS: Patients were included from the French National Cardiac Arrest Registry and were grouped based on the received dose of adrenaline: recommended, higher and lower dose. OUTCOME MEASURES AND ANALYSIS: The primary endpoint was good neurologic outcome at 30 days post-OHCA, defined by a cerebral performance category (CPC) of less than 3. Secondary endpoints included return of spontaneous circulation and survival to hospital discharge. A multiple propensity score adjustment approach was performed. MAIN RESULTS: 27 309 patients included from July 1st 2011 to January 1st 2019 were analysed, mean age was 68 (57-78) years and 11.2% had ventricular fibrillation. 588 (2.2%) patients survived with a good CPC score. After adjustment, patients in the high dose group had a significant lower rate of good neurologic outcome (OR, 0.6; 95% CI, 0.5-0.7). There was no significant difference for the primary endpoint in the lower dose group (OR, 0.8; 95% CI, 0.7-1.1). There was a lower rate of survival to hospital discharge in the high-dose group vs. standard group (OR, 0.5; 95% CI, 0.5-0.6). CONCLUSION: The use of lower doses of adrenaline was not associated with a significant difference on survival good neurologic outcomes at D30. But a higher dose of adrenaline was associated with a lower rate of survival with good neurological outcomes and poorer survival at D30.

Head-to-head comparison of diagnostic scores for acute heart failure in the emergency department: results from the PARADISE cohort.

BREST and PREDICA scores have recently emerged for the diagnosis of acute heart failure (AHF) in the emergency department (ED). This study aimed to perform a head-to-head comparison in a large contemporary cohort. BREST and PREDICA scores were calculated from, respectively, 11 and 8 routine clinical variables recorded in the ED in 1386 patients from the PArADIsE cohort. The diagnostic performance of the scores for adjudicated AHF diagnosis was assessed by the area under the ROC curve (AUC). Acute HF diagnosis was adjudicated according to the European Society of Cardiology criteria and BNP levels. A BREST score ≤ 3 or PREDICA score ≤ 1 was associated with low probabilities of AHF (5.7% and 2.6%, respectively). Conversely, a BREST score ≥ 9 or PREDICA score ≥ 5 was associated with a high risk of AHF diagnosis (77.3% and 66.9%, respectively) although more than half of the population was within the "gray zone" (4-8 and 2-4 for the BREST and PREDICA scores, respectively). Diagnostic performances of both scores were good (AUC 79.1%, [66.1-82.1] for the BREST score and 82.4%, [79.8-85.0] for the PREDICA score). PREDICA score had significantly higher diagnostic performance than BREST score (increase in AUC 3.3 [0.8-5.8], p = 0.009). Our study emphasizes the good diagnostic performance of both BREST and PREDICA scores, albeit with a significantly higher diagnostic performance of the PREDICA score. Yet, more than half of the population was classified within the "gray zone" by these scores; additional diagnostic tools are needed to ascertain AHF diagnosis in the ED in a majority of patients. Clinical trial registration: NCT02800122.

IMPACT OF DIFFERENT VENTILATION STRATEGIES ON GAS EXCHANGES AND CIRCULATION DURING PROLONGED MECHANICAL CARDIO-PULMONARY RESUSCITATION IN A PORCINE MODEL.

ABSTRACT: Background: Optimal ventilation during cardio-pulmonary resuscitation (CPR) is still controversial. Ventilation is expected to provide sufficient arterial oxygen content and adequate carbon dioxide removal, while minimizing the risk of circulatory impairment. The objective of the present study was to compare three ventilation strategies in a porcine model during mechanical continuous chest compressions (CCC) according to arterial oxygenation and hemodynamic impact. Method: Ventricular fibrillation was induced and followed by five no-flow minutes and thirty low-flow minutes resuscitation with mechanical-CCC without vasopressive drugs administration. Three groups of eight Landras pig were randomized according to the ventilation strategy: 1. Standard nonsynchronized volume-control mode (SD-group); 2. synchronized bilevel pressure-controlled ventilation (CPV-group); 3. continuous insufflation with Boussignac Cardiac-Arrest Device (BC-group). We assessed 1. arterial blood gases, 2. macro hemodynamics, 3. tissular cerebral macro and micro-circulation and 4. airway pressure, minute ventilation at baseline and every 5 minutes during the protocol. Results: Arterial PaO2 level was higher at each measurement time in SD-group (>200 mm Hg) compare to CPV-group and BC-group ( P < 0.01). In BC-group, arterial PaCO2 level was significantly higher (>90mm Hg) than in SD and CPV groups ( P < 0.01). There was no difference between groups concerning hemodynamic parameters, cerebral perfusion and microcirculation. Conclusion: Ventilation modalities in this porcine model of prolonged CPR influence oxygenation and decarboxylation without impairing circulation and cerebral perfusion. Synchronized bi-level pressure-controlled ventilation' use avoid hyperoxia and was as efficient as asynchronized volume ventilation to maintain alveolar ventilation and systemic perfusion during prolonged CPR.

Mildly Reduced Doses of Adrenaline Do Not Affect Key Hemodynamic Parameters during Cardio-Pulmonary Resuscitation in a Pig Model of Cardiac Arrest.

Adrenaline is recommended for cardiac arrest resuscitation, but its effectiveness has been questioned recently. Achieving return of spontaneous circulation (ROSC) is essential and is obtained by increasing coronary perfusion pressure (CPP) after adrenaline injection. A threshold as high as 35 mmHg of CPP may be necessary to obtain ROSC, but increasing doses of adrenaline might be harmful to the brain. Our study aimed to compare the increase in CPP with reduced doses of adrenaline to the recommended 1 mg dose in a pig model of cardiac arrest. Fifteen domestic pigs were randomized into three groups according to the adrenaline doses: 1 mg, 0.5 mg, or 0.25 mg administered every 5 min. Cardiac arrest was induced by ventricular fibrillation; after 5 min of no-flow, mechanical chest compression was resumed. The Wilcoxon test and Kruskal-Wallis exact test were used for the comparison of groups. Fisher's exact test was used to compare categorical variables. CPP, EtCO2 level, cerebral, and tissue near-infrared spectroscopy (NIRS) were measured. CPP was significantly lower in the 0.25 mg group 90 s after the first adrenaline injection: 28.9 (21.2; 35.4) vs. 53.8 (37.8; 58.2) in the 1 mg group (p = 0.008), while there was no significant difference with 0.5 mg 39.6 (32.7; 52.5) (p = 0.056). Overall, 0.25 mg did not achieve the threshold of 35 mmHg. EtCO2 levels were higher at T12 and T14 in the 0.5 mg than in the standard group: 32 (23; 35) vs. 19 (16; 26) and 26 (20; 34) vs. 19 (12; 22) (p < 0.05). Cerebral and tissue NIRS did not show a significant difference between the three groups. CPP after 0.5 mg boluses of adrenaline was not significantly different from the recommended 1 mg in our model of cardiac arrest.