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Objectives: Our goal was to evaluate the associations between postoperative coronary perfusion pressure (CPP) values and in-hospital outcomes in infants after congenital cardiac surgery. Our goal was to assess the relationship between postoperative coronary perfusion pressure (CPP) values and in-hospital outcomes in infants following congenital cardiac surgery. Methods: In this study, we conducted a retrospective analysis on a cohort of 296 consecutive infant patients (aged 31–120 days) who underwent congenital cardiac surgery between 1 January 2019 and 30 April 2019. A total of 208 patients undergoing congenital cardiac surgery were included. The primary poor in-hospital outcome was prolonged recovery. The association between CPP level and in-hospital outcomes was determined using logistic regression analysis. We also used restricted cubic splines (RCSs) to evaluate the nonlinear relationship. Results: Our study included 208 participants, among whom the mortality rate was 1%. Prolonged hospital length of stay (LOS) was defined as more than 15 days, prolonged mechanical ventilation (MV) stay as more than 96 h, and prolonged intensive care unit (ICU) LOS as more than 403 h. In univariate analyses, we found that prolonged recovery was associated with both low CPP levels (p < 0.001, OR 4.28, 95% CI 1.94–9.46) and high CPP levels (p = 0.003, OR 3.39, 95% CI 1.52–7.58). In multivariable logistic regression analysis, after full adjustment, low CPP levels and high CPP levels were significantly associated with prolonged recovery (p = 0.005, OR = 3.72, 95% CI 1.48–9.35 and p < 0.001, OR = 6.04, 95% CI 2.32–15.72, respectively). We observed that the relationship between CPP level and poor in-hospital outcomes was U-shaped in a two-piecewise linear regression analysis. We found that the inflection point of CPP level for prolonged recovery was 47 mm Hg. Conclusion: The CPP levels exhibited a nonlinear relationship with poor in-hospital outcomes. [ABSTRACT FROM AUTHOR]

Objectives: Our goal was to evaluate the associations between postoperative coronary perfusion pressure (CPP) values and in-hospital outcomes in infants after congenital cardiac surgery. Our goal was to assess the relationship between postoperative coronary perfusion pressure (CPP) values and in-hospital outcomes in infants following congenital cardiac surgery. Methods: In this study, we conducted a retrospective analysis on a cohort of 296 consecutive infant patients (aged 31–120 days) who underwent congenital cardiac surgery between 1 January 2019 and 30 April 2019. A total of 208 patients undergoing congenital cardiac surgery were included. The primary poor in-hospital outcome was prolonged recovery. The association between CPP level and in-hospital outcomes was determined using logistic regression analysis. We also used restricted cubic splines (RCSs) to evaluate the nonlinear relationship. Results: Our study included 208 participants, among whom the mortality rate was 1%. Prolonged hospital length of stay (LOS) was defined as more than 15 days, prolonged mechanical ventilation (MV) stay as more than 96 h, and prolonged intensive care unit (ICU) LOS as more than 403 h. In univariate analyses, we found that prolonged recovery was associated with both low CPP levels (p < 0.001, OR 4.28, 95% CI 1.94–9.46) and high CPP levels (p = 0.003, OR 3.39, 95% CI 1.52–7.58). In multivariable logistic regression analysis, after full adjustment, low CPP levels and high CPP levels were significantly associated with prolonged recovery (p = 0.005, OR = 3.72, 95% CI 1.48–9.35 and p < 0.001, OR = 6.04, 95% CI 2.32–15.72, respectively). We observed that the relationship between CPP level and poor in-hospital outcomes was U-shaped in a two-piecewise linear regression analysis. We found that the inflection point of CPP level for prolonged recovery was 47 mm Hg. Conclusion: The CPP levels exhibited a nonlinear relationship with poor in-hospital outcomes.

Background: Myocardial perfusion is an important determinant of cardiac function. We hypothesized that low coronary perfusion pressure (CPP) would be associated with adverse outcomes in heart failure. Myocardial perfusion impacts the contractile efficiency thus a low CPP would signal low myocardial perfusion in the face of increased cardiac demand as a result of volume overload. Methods: We analyzed patients with complete hemodynamic data in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness trial using Cox Proportional Hazards regression for the primary outcome of the composite risk of death, heart transplantation, or left ventricular assist device [(LVAD). DT × LVAD] and the secondary outcome of the composite risk of DT × LVAD and heart failure hospitalization (DT × LVADHF). CPP was calculated as the difference between diastolic blood pressure and pulmonary artery wedge pressure. Heart failure categories (ischemic vs non-ischemic) were also stratified based on CPP strata. Results: The 158 patients (56.7 ± 13.6 years, 28.5% female) studied had a median CPP of 40 mmHg (IQR 35–52 mmHg). During 6 months of follow-up, 35 (22.2%) had the composite primary outcome and 109 (69.0%) had the composite secondary outcome. When these outcomes were then stratified based on the median, CPP was associated with these outcomes. Increasing CPP was associated with lower risk of both the primary outcome of DT × LVAD (HR 0.96, 95% CI 0.94–0.99 p =.002) and as well as the secondary outcome of DT × LVADHF (p =.0008) There was significant interaction between CPP and ischemic etiology (p =.04). Conclusion: A low coronary artery perfusion pressure below (median) 40mmHg in patients with advanced heart failure undergoing invasive hemodynamic monitoring with a pulmonary artery catheter was associated with adverse outcomes. CPP could useful in guiding risk stratification of advanced heart failure patients and timely evaluation of advanced heart failure therapies. [ABSTRACT FROM AUTHOR]

Introduction: The presented study aimed to investigate whether a mechanical chest compression piston device with a suction cup assisting chest recoil could impact the hemodynamic status when compared to a bare piston during cardiopulmonary resuscitation. Methods: 16 piglets were anesthetized and randomized into 2 groups. After 3 minutes of induced ventricular fibrillation, a LUCAS 3 device was used to perform chest compressions, in one group a suction cup was mounted on the device’s piston, while in the other group, compressions were performed by the bare piston. The device was used in 30:2 mode and the animals were manually ventilated. Endpoints of the study were: end tidal carbon dioxide, coronary and cerebral perfusion pressures, and brain oxygenation (measured using near infrared spectroscopy). At the end of the protocol, the animals that got a return to spontaneous circulation were observed for 60 minutes, then euthanized. Results: No difference was found in end tidal carbon dioxide or tidal volumes. Coronary perfusion pressure and cerebral oxygenation were higher in the Suction cup group over the entire experiment time, while cerebral perfusion pressure was higher only in the last 5 minutes of CPR. A passive tidal volume (air going in and out the airways during compressions) was detected and found correlated to end tidal carbon dioxide. Conclusions: The use of a suction cup on a piston-based chest compression device did not increase end tidal carbon dioxide, but it was associated to a higher coronary perfusion pressure.

Aim Of the Study: Resuscitative endovascular balloon occlusion of the aorta (REBOA), originally designed to block blood flow to the distal part of the aorta by placing a balloon in trauma patients, has recently been shown to increase coronary perfusion in cardiac arrest patients. This study evaluated the effect of REBOA on aortic pressure and coronary perfusion pressure (CPP) in non-traumatic out of-hospital cardiac arrest (OHCA) patients.Methods: Adult OHCA patients with cerebral performance category 1 or 2 prior to cardiac arrest, and without evidence of aortic disease, were enrolled from January to December 2021. Aortic pressure and right atrial pressure were measured before and after balloon occlusion. The CPP was calculated using the measured aortic and right atrial pressures, and the values before and after the balloon occlusion were compared.Results: Fifteen non-traumatic OHCA patients were enrolled in the study. The median call to balloon time was 46.0 (IQR, 38.0-54.5) min. The median CPP before and after balloon occlusion was 13.5 (IQR, 5.8-25.0) and 25.2 (IQR, 12.0-44.6) mmHg, respectively (P = 0.001). The median increase in the estimated CPP after balloon occlusion was 86.7%.Conclusions: The results of this study suggest that REBOA may increase the CPP during cardiopulmonary resuscitation in patients with non-traumatic OHCA. Additional studies are needed to investigate the effect on clinical outcomes. [ABSTRACT FROM AUTHOR]

Abstract Aims Right ventricle adaptation to prolonged exposure against pulmonary hypertension (PH) includes structural and functional abnormalities, translated into modifications of blood flow pattern through the right coronary artery. Given these changes, we investigate the relationship between right coronary artery diastolic perfusion pressure (RCDPP) and clinical outcome, in patients with PH secondary to left‐sided heart failure (HF). Methods and results We studied 108 HF patients who underwent right heart catheterization. PH was present in 75 (69.4%). Mean RCDPP was lower in patients with PH (59.4 ± 14.0 mmHg) as compared with no PH patients (65.5 ± 11.6 mmHg) (P = 0.03). Aortic diastolic pressure accounted for 79% of RCDPP variability explained by the model (P

• This study proposes a novel noninvasive estimation method for CPP using machine learning based on ECG and PPG. • The estimations based on the combined ECG and PPG datasets were relatively better than those based on either ECG or PPG. • Compared to SVR, KNN, and GBRT, the RF model provided a better estimation of CPPs. • The CPP estimation for the ROSC group showed higher R-values than the estimation for all populations. Coronary perfusion pressure (CPP) indicates spontaneous return of circulation and is recommended for high-quality cardiopulmonary resuscitation (CPR). This study aimed to investigate a method for non-invasive estimation of CPP using electrocardiography (ECG) and photoplethysmography (PPG) during CPR. Nine pigs were used in this study. ECG, PPG, invasive arterial blood pressure (ABP), and right atrial pressure (RAP) signals were simultaneously recorded. The CPPs were estimated using three datasets: (a) ECG, (b) PPG, and (c) ECG and PPG, and were compared with invasively measured CPPs. Four machine-learning algorithms, namely support vector regression, random forest (RF), K-nearest neighbor, and gradient-boosted regression tree, were used for estimation of CPP. The RF model with a combined ECG and PPG dataset achieved better estimation of CPP than the other algorithms. Specifically, the mean absolute error was 4.49 mmHg, the root mean square error was 6.15 mm Hg, and the adjusted R2 was 0.75. A strong correlation was found between the non-invasive estimation and invasive measurement of CPP (r = 0.88), which supported our hypothesis that machine-learning-based analysis of ECG and PPG parameters can provide a non-invasive estimation of CPP for CPR. This study proposes a novel estimation of CPP using ECG and PPG with machine-learning-based algorithms. Non-invasively estimated CPP showed a high correlation with invasively measured CPP and may serve as an easy-to-use physiological indicator for high-quality CPR treatment. [ABSTRACT FROM AUTHOR]

BackgroundCoronary perfusion pressure (CPP) and coronary artery stenosis are responsible for myocardial perfusion. However, how CPP-related survival outcome affects revascularization is unclear.ObjectiveThe aim of this study is to investigate the prognostic role of CPP in patients with left ventricular systolic dysfunction (LVSD) undergoing percutaneous coronary intervention (PCI) with complete revascularization (CR) or reasonable incomplete revascularization (RIR).MethodsWe retrospectively screened 6,076 consecutive patients in a registry. The residual synergy between percutaneous coronary intervention with Taxus and cardiac surgery (SYNTAX) score (rSS) was used to define CR (rSS = 0) and RIR (0 42 mmHg. Moreover, 101 pairs of RIR and CR were present in patients with CPP ≤ 42 mmHg. In patients with CPP > 42 mmHg, RIR was not significantly different from CR in long-term mortality [hazard ratio (HR) 1.20; 95% confidence interval (CI):0.70–2.07; p = 0.513]; However, in patients with CPP≤42 mmHg, RIR had a significantly higher mortality risk than CR (HR 2.39; 95% CI: 1.27–4.50; p = 0.007).ConclusionsThe CPP had a risk stratification role in selecting different revascularization strategies in patients with LVSD. When patients with LVSD had CPP > 42 mmHg, RIR was equivalent to CR in survival. However, when patients with LVSD had CPP ≤ 42 mmHg, RIR had a significantly higher mortality risk than CR.

Aims Right ventricle adaptation to prolonged exposure against pulmonary hypertension (PH) includes structural and functional abnormalities, translated into modifications of blood flow pattern through the right coronary artery. Given these changes, we investigate the relationship between right coronary artery diastolic perfusion pressure (RCDPP) and clinical outcome, in patients with PH secondary to left-sided heart failure (HF). Methods and results We studied 108 HF patients who underwent right heart catheterization. PH was present in 75 (69.4%). Mean RCDPP was lower in patients with PH (59.4 ± 14.0 mmHg) as compared with no PH patients (65.5 ± 11.6 mmHg) (P = 0.03). Aortic diastolic pressure accounted for 79% of RCDPP variability explained by the model (P < 0.0001). During a median follow-up of 26 months, the RCDPP 1st tertile (<55 mmHg) [hazard ration (HR) 5.19, 95% confidence interval (CI) 1.08–25.12, P = 0.04] and left ventricular ejection fraction <45% [HR 7.26, 95% CI 1.77–29.73, P = 0.006] were independent predictors of mortality. Conclusions Right coronary artery diastolic perfusion pressure is a strong independent haemodynamic maker of mortality in left-sided HF and PH. Excessive reduction of aortic diastolic pressure may be detrimental. Future research is necessary to determine the therapeutic approach to blood pressure in this population. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the mean aortic-right atrial pressure (AoP-RAP) gradients and mean coronary perfusion pressures (CPPs) observed during open cardiac massage (OCM) versus those obtained with selective aortic arch perfusion (SAAP) in post-mortem hypovolemic swine.Methods: Post-mortum, male swine, utilized in prior studies of hemorrhage, were included in the study. Animals were bled ∼25-50% of circulating volume prior to death. Animals either underwent clamshell thoracotomy and OCM immediately after death was confirmed (n = 6) or underwent SAAP within 5-15 min of death (n = 6). Aortic root and right atrial pressures were recorded continuously during each method of resuscitation using solid state blood pressure catheters. Representative five beat samples were extracted; short, similarly timed segments of SAAP were also extracted. Mean AoP-RAP gradient and CPPs were calculated and compared.Results: Mean AoP-RAP gradient and CPP were significantly higher in SAAP animals compared to OCM animals (mean ± SD; 29.1 ± 8.4 vs. 24.5 ± 5.0, p < 0.001; 28.9 ± 8.5 vs. 9.9 ± 6.0, p < 0.001). Mean CPP was not significantly different from mean AoP-RAP gradient in SAAP animals (p = 0.92); mean CPP was significantly lower than mean AoP-RAP gradient in OCM animals (p < 0.001). While 97% of SAAP segments had a CPP > 15 mmHg, only 17% of OCM segments had a CPP > 15 mmHg (p < 0.001).Conclusion: SAAP appears to create a more favorable and efficient hemodynamic profile for obtaining ROSC when compared to OCM in this preclinical porcine study. [ABSTRACT FROM AUTHOR]

Aim: Compare vasopressin to a second dose of epinephrine as rescue therapy after ineffective initial doses of epinephrine in diverse models of pediatric in-hospital cardiac arrest. Methods: 67 one- to three-month old female swine (10−30 kg) in six experimental cohorts from one laboratory received hemodynamic-directed CPR, a resuscitation method where high quality chest compressions are provided and vasopressor administration is titrated to coronary perfusion pressure (CoPP) ≥20 mmHg. Vasopressors are given when CoPP is

Background Epinephrine increases the rate of return of spontaneous circulation. However, it increases severity of postresuscitation myocardial and cerebral dysfunction and reduces duration of survival. We investigated the effects of aortic infused polyethylene glycol, 20 000 molecular weight (PEG‐20k) during cardiopulmonary resuscitation on coronary perfusion pressure, postresuscitation myocardial and cerebral function, and duration of survival in a rat model of cardiac arrest. Methods and Results Twenty‐four male rats were randomized into 4 groups: (1) PEG‐20k, (2) epinephrine, (3) saline control–intravenous, and (4) saline control–intra‐aortic. Cardiopulmonary resuscitation was initiated after 6 minutes of untreated ventricular fibrillation. In PEG‐20k and Saline‐A, either PEG‐20k (10% weight/volume in 10% estimated blood volume infused over 3 minutes) or saline was administered intra‐aortically after 4 minutes of precordial compression. In epinephrine and placebo groups, either epinephrine (20 μg/kg) or saline placebo was administered intravenously after 4 minutes of precordial compression. Resuscitation was attempted after 8 minutes of cardiopulmonary resuscitation. Sublingual microcirculation was measured at baseline and 1, 3, and 5 hours after return of spontaneous circulation. Myocardial function was measured at baseline and 2, 4, and 6 hours after return of spontaneous circulation. Neurologic deficit scores were recorded at 24, 48, and 72 hours after return of spontaneous circulation. Aortic infusion of PEG‐20k increased coronary perfusion pressure to the same extent as epinephrine. Postresuscitation sublingual microcirculation, myocardial and cerebral function, and duration of survival were improved in PEG‐20k (P

Aim: Controlled sequential elevation of the head and thorax (CSE) during active compression-decompression (ACD) CPR with an impedance threshold device (ITD) augments cerebral (CerPP) and coronary (CorPP) perfusion pressures. The optimal CSE is unknown.Methods: After 8 minutes of untreated VF, 40 kg anesthetized female pigs were positioned on a customized head and thorax elevation device (CED). After 2 min of automated ACD + ITD-16 CPR to 'prime the system', 12 pigs were randomized to CSE to the highest CED position over 4-min or 10-min. The primary outcome was CerPP after 7 minutes of CPR. Secondarily, 24-sec (without a priming step) and 2-min CSE times were similarly tested (n = 6 group) in a non-randomized order. Values expressed as mean ± SD.Results: After 7 min of CPR, CerPPs were significantly higher in the 4-min vs 10-min CSE groups (53 ± 14.4 vs 38.5 ± 3.6 mmHg respectively, p = 0.03) whereas CorPP trended higher. The 4-min CSE group achieved 50% of baseline (50% BL) CerPP faster than the 10-min group (2.5 ± 1.2 vs 6 ± 3.1 minutes, p = 0.03). CerPP values in the 2-min and 4-min CSE groups were significantly higher than in the 24-sec group. With CSE, CerPPs and CorPPs increased over time in all groups.Conclusions: By optimizing controlled sequential elevation timing, CerPP values achieved 50% of baseline within less than 2.5 minutes and >80% of baseline after 7 minutes of CPR. This novel CPR approach rapidly restored CerPPs to near normal values non-invasively and without vasopressors. [ABSTRACT FROM AUTHOR]

Aim: We examined the use of a Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) catheter during cardiopulmonary resuscitation (CPR) after cardiac arrest (CA) to assess its effect on haemodynamics such as coronary perfusion pressure (CPP), common carotid artery blood flow (CCA-flow) and end-tidal CO2 (PetCO2) which are associated with increased return of spontaneous circulation (ROSC).Methods: Six male swine were instrumented to measure CPP, CCA-Flow, and PetCO2. A 7Fr REBOA was advanced into zone-1 of the aorta through the femoral artery. Ventricular fibrillation was induced and untreated for 8 min. CPR (manual then mechanical) was initiated for 24 min. Continuous infusion of adrenaline (epinephrine) was started at minute-4 of CPR. The REBOA balloon was inflated at minute-16 for 3 min and then deflated/inflated every 3 min for 3 cycles. Animals were defibrillated up to 6 times after the final cycle. Animals achieving ROSC were monitored for 25 min.Results: Data showed significant differences between balloon deflation and inflation periods for CPP, CCA-Flow, and PetCO2 (p < 0.0001) with an average difference (SD) of 13.7 (2.28) mmHg, 15.5 (14.12) mL min-1 and -4 (2.76) mmHg respectively. Three animals achieved ROSC and had significantly higher mean CPP (54 vs. 18 mmHg), CCA-Flow (262 vs. 135 mL min-1) and PetCO2 (16 vs. 8 mmHg) (p < 0.0001) throughout inflation periods than No-ROSC animals. Aortic histology did not reveal any significant changes produced by balloon inflation.Conclusion: REBOA significantly increased CPP and CCA-Flow in this model of prolonged CA. These increases may contribute to the ability to achieve ROSC. [ABSTRACT FROM AUTHOR]

Background/purpose: Appropriate patient selection for mechanical circulatory support following percutaneous coronary intervention (PCI) remains a challenge. This study aims to evaluate the role of coronary perfusion pressure and other left ventricular hemodynamics to predict cardiovascular collapse following PCI.Methods/materials: We retrospectively analyzed all patients who underwent PCI for acute coronary syndrome (ACS) from 2003 to 2016. Coronary perfusion pressure was calculated for each patient and defined as the difference in mean arterial pressure and left ventricular end diastolic pressure (LVEDP). Logistic regression analysis was performed to determine predictor of composite outcome of in-hospital mortality, myocardial infarction (MI), congestive heart failure (CHF), and cardiogenic shock.Results: Nine hundred twenty-two patients were analyzed. Two-hundred twenty-eight (25%) presented with ST-elevation MI (STEMI) while 694 (75%) underwent PCI for unstable angina or non-Q-wave MI. The mean LVEDP was significantly higher in the STEMI patients (24 ± 9 vs. 19 ± 8 mm Hg, p < 0.05) and perfusion pressure significantly lower (68 ± 24 vs. 74 ± 18 mm Hg, p < 0.05). Eighty-seven (9.4%) reached the composite endpoint, and there was no difference between the STEMI and Not-STEMI groups. Neither LVEDP nor coronary perfusion pressure was a predictor of the composite outcome following multivariable logistic regression analysis for either STEMI or Not-STEMI patients. Increasing age, chronic renal insufficiency (CRI), CHF, and low left ventricular ejection fraction were predictors of the composite outcome for Not-STEMI patients, whereas only history of cerebrovascular accident and CRI were predictors for STEMI patients.Conclusions: In hemodynamically stable patients presenting with ACS, LVEDP and coronary perfusion pressure are not predictive of in-hospital cardiovascular collapse.Summary: The authors retrospectively analyzed 922 patients from a single center who underwent percutaneous coronary intervention (PCI) for acute coronary syndromes to evaluate the role of coronary perfusion pressure and other left ventricular hemodynamics to predict cardiovascular collapse following PCI. They found that neither coronary perfusion pressure nor left ventricular end diastolic pressure was predictive of in-hospital cardiovascular collapse. [ABSTRACT FROM AUTHOR]

This is a case report of a 77-year-old man with severe symptomatic aortic stenosis who underwent removal of an impacted ureteral stone under general anesthesia. During emergence from general anesthesia, his legs were lowered from lithotomy position, resulting in sudden hypotension with progression to pulseless electrical activity. The legs were raised and placed into full flexion of the hips and knees. This maneuver was temporally related to a return of spontaneous circulation and full recovery. Possible mechanisms for this effect are discussed. [ABSTRACT FROM AUTHOR]

Objective: It is unknown whether patient position is associated with the optimal cerebral (CePP) and coronary (CoPP) perfusion pressure.Methods: This study utilized a randomized experimental design and anesthetized, intubated and paralyzed female pigs (n=12) (mean 42, SD 3kg). After 6min of untreated ventricular fibrillation, mechanical CPR with was performed for 3min in 0° supine position. The CPR was then performed for 5min in a position randomly assigned to either 1) head-up tilt (HUT) by three angles (30°, 45°, or 60°) or 2) head-down tilt (HDT) by three angles (30°, 45°, or 60°) and at 3) supine position between HUT and HDT positions. 4 Pigs were assigned to each angle of HUT or HDT position and 12 pigs were assigned to supine position. CePPs and CoPPs were measured and compared using MIXED procedure with pig as a random effect among angles and compared between angles with Tukey post-hoc analysis.Results: With 60°, 45°, 30° head-down, 0° (supine), and 30°, 45°, 60° head-up positioning, mean(SD) CePPs increased consistently as follows: 2.4(0.4), 9.3(1.6), 16.5(1.6), 27.0(1.5), 35.1(0.4), 39.4(0.6), and 39.9(0.3) mmHg, respectively. CoPPs were followings according to same angle: 12.9(2.5), 13.3(2.5), 12.8(0.4), 18.1(0.7), 30.3(0.4), 24.1(0.6), and 26.5(0.9) mmHg, respectively. The CePPs were peak at HUT(45°) and HUT(60°), but CoPP was peak in HUT(30°) and higher than HUT(45°) and HUT(60°).Conclusion: Cerebral perfusion pressure during mechanical CPR were similar and highest in the HUT(45° and 60°) positions whereas the peak coronary perfusion pressure was observed with HUT(30°). [ABSTRACT FROM AUTHOR]

Aim: Most pediatric in-hospital cardiac arrests (IHCAs) occur in ICUs where invasive hemodynamic monitoring is frequently available. Titrating cardiopulmonary resuscitation (CPR) to the hemodynamic response of the individual improves survival in preclinical models of adult cardiac arrest. The objective of this study was to determine if titrating CPR to systolic blood pressure (SBP) and coronary perfusion pressure (CoPP) in a pediatric porcine model of asphyxia-associated ventricular fibrillation (VF) IHCA would improve survival as compared to traditional CPR.Methods: After 7min of asphyxia followed by VF, 4-week-old piglets received either hemodynamic-directed CPR (HD-CPR; compression depth titrated to SBP of 90mmHg and vasopressor administration to maintain CoPP ≥20mmHg); or Standard Care (compression depth 1/3 of the anterior-posterior chest diameter and epinephrine every 4min). All animals received CPR for 10min prior to the first defibrillation attempt. CPR was continued for a maximum of 20min. Protocolized intensive care was provided to all surviving animals for 4h. The primary outcome was 4-h survival.Results: Survival rate was greater with HD-CPR (12/12) than Standard Care (6/10; p=0.03). CoPP during HD-CPR was higher compared to Standard Care (point estimate +8.1mmHg, CI95: 0.5-15.8mmHg; p=0.04). Chest compression depth was lower with HD-CPR than Standard Care (point estimate -14.0mm, CI95: -9.6 to -18.4mm; p<0.01). Prior to the first defibrillation attempt, more vasopressor doses were administered with HD-CPR vs. Standard Care (median 5 vs. 2; p<0.01).Conclusions: Hemodynamic-directed CPR improves short-term survival compared to standard depth-targeted CPR in a porcine model of pediatric asphyxia-associated VF IHCA. [ABSTRACT FROM AUTHOR]

Increasing venous return during cardiopulmonary resuscitation (CPR) has been shown to improve hemodynamics during CPR and outcomes following cardiac arrest (CA). We hypothesized that a high central venous pressure amplitude (CVP-A), the difference between the maximum and minimum central venous pressure during chest compressions, could serve as a robust predictor of return of spontaneous circulation (ROSC) in addition to traditional measurements of coronary perfusion pressure (CPP) and end-tidal CO 2 (etCO 2) in a porcine model of CA. After 10 min of ventricular fibrillation, 9 anesthetized and intubated female pigs received mechanical chest compressions with active compression/decompression (ACD) and an impedance threshold device (ITD). CPP, CVP-A and etCO 2 were measured continuously. All groups received biphasic defibrillation (200 J) at minute 4 of CPR and were classified into two groups (ROSC, NO ROSC). Mean values were analyzed over 3 min before defibrillation by repeated-measures Analysis of Variance and receiver operating characteristic (ROC). Five animals out of 9 experienced ROSC. CVP-A showed a statistically significant difference (p = 0.003) between the two groups during 3 min of CPR before defibrillation compared to CPP (p = 0.056) and etCO 2 (p = 0.064). Areas-under-the-curve in ROC analysis for CVP-A, CPP and etCO 2 were 0.94 (95% Confidence Interval 0.86, 1.00), 0.74 (0.54, 0.95) and 0.78 (0.50, 1.00), respectively. In our study, CVP-A was a potentially useful predictor of successful defibrillation and return of spontaneous circulation. Overall, CVP-A could serve as a marker for prediction of ROSC with increased venous return and thereby monitoring the beneficial effects of ACD and ITD. [ABSTRACT FROM AUTHOR]

Objectives: Treatment algorithms for cardiac arrest are rescuer centric and vary little from patient to patient. The objective of this study was to determine if cardiopulmonary resuscitation-targeted to arterial blood pressure and coronary perfusion pressure rather than optimal guideline care would improve 24-hour survival in a porcine model of ventricular fibrillation cardiac arrest.Data Sources: Preclinical animal laboratory using female 3-month-old swine.Study Selection: A randomized interventional study.Data Extraction: After induction of anesthesia and 7 minutes of untreated ventricular fibrillation, 16 female 3-month-old swine were randomized to 1) blood pressure care: titration of chest compression depth to a systolic blood pressure of 100 mm Hg and vasopressor dosing to maintain coronary perfusion pressure of greater than 20 mm Hg or 2) guideline care: chest compression depth targeted to 51 mm and standard guideline vasopressor dosing. Animals received manual cardiopulmonary resuscitation for 10 minutes before the first defibrillation attempt and standardized postresuscitation care for 24 hours.Data Synthesis: Twenty-four-hour survival was more likely with blood pressure care versus guideline care (0/8 vs 5/8; p < 0.03), and all survivors had normal neurologic examinations. Mean coronary perfusion pressure prior to defibrillation was significantly higher with blood pressure care (28 ± 3 vs 10 ± 6 mm Hg; p < 0.01). Chest compression depth was lower with blood pressure care (48 ± 0.4 vs 44 ± 0.5 mm Hg; p < 0.05), and the number of vasopressor doses was higher with blood pressure care (median, 3 [range, 1-7] vs 2 [range, 2-2]; p < 0.01).Conclusions: Individualized goal-directed hemodynamic resuscitation targeting systolic blood pressure of 100 mm Hg and coronary perfusion pressure of greater than 20 mm Hg improved 24-hour survival compared with guideline care in this model of ventricular fibrillation cardiac arrest. [ABSTRACT FROM AUTHOR]

Aim of the study To examine the effects of Shenfu injection (SFI) on macrocirculation and microcirculation during ventricular fibrillation (VF) and cardiopulmonary resuscitation (CPR). Materials and methods Sixteen female Landrace pigs were used in this study. After anesthesia, coronary perfusion pressure (CPP) was measured, and then the abdominal cavity was opened to observe the mesenteric microcirculation with the aid of sidestream dark field imaging. Following the guidelines, we determined microvascular flow index, perfused vessel density and proportion of perfused vessels both for large (diameter>20 μm) and small (diameter<20 μm) microvessels. SFI (1 ml/kg) or saline was given by vein injection at 1 h before inducing VF. CPR was initiated after 4 min VF. Results The shocks and duration of CPR were less in the SFI group compared with saline group. As the occurrence of VF, the CPP suddenly dropped to near zero, and cannot be measured in the both groups. However, there was greater CPP during CPR and at 1 h after return of spontaneous circulation in the SFI group than saline group. Compared with saline, SFI significantly improved the microcirculation parameters of large and small microvessels during VF and CPR. Conclusions SFI can improve the microvascular blood flow and CPP during VF and CPR, and reduce the shocks and duration of CPR. [ABSTRACT FROM AUTHOR]

High-quality cardiopulmonary resuscitation contributes to cardiac arrest survival. The traditional chest compression (CC) standard, which neglects individual differences, uses unified standards for compression depth and compression rate in practice. In this study, an effective and personalized CC method for automatic mechanical compression devices is provided. We rebuild Charles F. Babbs' human circulation model with a coronary perfusion pressure (CPP) simulation module and propose a closed-loop controller based on a fuzzy control algorithm for CCs, which adjusts the CC depth according to the CPP. Compared with a traditional proportion-integration-differentiation (PID) controller, the performance of the fuzzy controller is evaluated in computer simulation studies. The simulation results demonstrate that the fuzzy closed-loop controller results in shorter regulation time, fewer oscillations and smaller overshoot than traditional PID controllers and outperforms the traditional PID controller for CPP regulation and maintenance. [ABSTRACT FROM AUTHOR]

It is known that a large proportion of patients with arterial hypertension are undertreated. This may result in an increase of the incidence of cardiovascular events. On the other hand, aggressive reduction of blood pressure may increase cardiovascular events (J-curve phenomenon) in certain populations. This phenomenon may be seen in patients with coronary artery disease and left ventricular hypertrophy when the diastolic blood pressure decreases below 70-80 mm Hg, and the systolic blood pressure decreases below 130 mm Hg. This phenomenon is not seen in patients with stroke or renal disease. Thus, a safer and more conservative strategy should be applied in patients with coronary artery disease, left ventricular hypertrophy, elderly, and in patients with isolated systolic hypertension. This is depicted in the recently published European Society of Hypertension/European Society of Cardiology guidelines in which higher targets of blood pressure are suggested in certain cardiovascular diseases and in the elderly. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aim Advances in cardiopulmonary resuscitation (CPR) have focused on the generation and maintenance of adequate myocardial blood flow to optimize the return of spontaneous circulation and survival. Much of the morbidity associated with cardiac arrest survivors can be attributed to global brain hypoxic ischemic injury. The objective of this study was to compare cerebral physiological variables using a hemodynamic directed resuscitation strategy versus an absolute depth-guided approach in a porcine model of ventricular fibrillation (VF) cardiac arrest. Methods Intracranial pressure and brain tissue oxygen tension probes were placed in the frontal cortex prior to induction of VF in 21 female 3-month-old swine. After 7 min of VF, animals were randomized to receive one of three resuscitation strategies: (1) hemodynamic directed care (CPP-20): chest compressions (CCs) with depth titrated to a target systolic blood pressure of 100 mmHg and titration of vasopressors to maintain coronary perfusion pressure (CPP) >20 mmHg; (2) depth 33 mm (D33): target CC depth of 33 mm with standard American Heart Association (AHA) epinephrine dosing; or (3) depth 51 mm (D51): target CC depth of 51 mm with standard AHA epinephrine dosing. Results Cerebral perfusion pressures (CerePP) were significantly higher in the CPP-20 group compared to both D33 (p < 0.01) and D51 (p = 0.046), and higher in survivors compared to non-survivors irrespective of treatment group (p < 0.01). Brain tissue oxygen tension was also higher in the CPP-20 group compared to both D33 (p < 0.01) and D51 (p = 0.013), and higher in survivors compared to non-survivors irrespective of treatment group (p < 0.01). Subjects with a CPP >20 mmHg were 2.7 times more likely to have a CerePP >30 mmHg (p < 0.001). Conclusions Hemodynamic directed resuscitation strategy targeting coronary perfusion pressure >20 mmHg following VF arrest was associated with higher cerebral perfusion pressures and brain tissue oxygen tensions during CPR. [ABSTRACT FROM AUTHOR]

The effect of freeze-dried red wine (FDRW) on cardiac function and electrocardiogram (ECG) in Langendorff-isolated rat hearts was investigated. FDRW significantly decreased left ventricular pressure and coronary perfusion pressure, the latter being dependent on the activation of both phosphatidylinositol 3-kinase and eNOS. FDRW did not affect the QRS and QT interval in the ECG, although at 56 μg of gallic acid equivalents/mL, it prolonged PQ interval and induced a second-degree atrioventricular block in 3 out of 6 hearts. This is the first study demonstrating that at concentrations resembling a moderate consumption of red wine, FDRW exhibited negative inotropic and coronary vasodilating activity leaving unaltered ECG, whereas at very high concentrations, it induced arrhythmogenic effects. [ABSTRACT FROM AUTHOR]

Aim: Force due to leaning during cardiopulmonary resuscitation (CPR) negatively affects haemodynamics and intrathoracic airway pressures (ITP) in animal models and adults, but has not been studied in children. We sought to characterize the effects of sternal force (SF) comparable to leaning force on haemodynamics and ITP in anaesthetized children. Methods: Children (6 months to 8yrs) presenting for routine haemodynamic cardiac catheterization with anaesthesia and mechanical ventilation >6 months after cardiac transplant were studied. Haemodynamics and ITP were measured before and during incremental increases in SF of 10% and 20% body weight. Results: 20 subjects (5.4±1.7yrs of age and 18.3±3.3kg) were studied. Mean right atrial pressure (6.5±2.6 at baseline vs. 7.7±2.6 at 10% SF vs. 8.6±2.7mmHg at 20% SF), mean pulmonary capillary wedge pressure (10.2±2.9 at baseline vs. 11±3.3 at 10% SF vs. 11.8±3.4mmHg at 20% SF) and ITP (16.3±3.2 at baseline vs. 17.9±3.9 at 10% SF vs. 19.5±4cm H2O) all increased significantly with incremental SF (p <0.001 for all). Aortic systolic pressure (85±10mmHg at baseline vs. 83±10mmHg at 10% SF vs. 82±10mmHg at 20% SF, p =0.014) and coronary perfusion pressure (42±7mmHg at baseline vs. 39±7mmHg at 10% SF vs. 38±7mmHg at 20% SF, p <0.001) both decreased significantly with incremental SF. Conclusions: In asymptomatic, anaesthetized children after cardiac transplantation, sternal forces comparable to leaning previously reported to occur during CPR elevate ITP and right atrial pressure and decrease coronary perfusion pressure. These haemodynamic effects may be clinically important during CPR and warrant further study. [ABSTRACT FROM AUTHOR]

Objectives: During cardiopulmonary resuscitation, adequate coronary perfusion pressure is essential for establishing return of spontaneous circulation. Current American Heart Association guidelines recommend standardized interval administration of epinephrine for patients in cardiac arrest. The objective of this study was to compare short-term survival using a hemodynamic directed resuscitation strategy versus chest compression depth-directed cardiopulmonary resuscitation in a porcine model of cardiac arrest. Design: Randomized interventional study. Setting: Preclinical animal laboratory. Subjects: Twenty-four 3-month-old female swine. Interventions: After 7 minutes of ventricular fibrillation, pigs were randomized to receive one of three resuscitation strategies: 1) Hemodynamic directed care (coronary perfusion pressure-20): chest compressions with depth titrated to a target systolic blood pressure of 100 mm Hg and titration of vasopressors to maintain coronary perfusion pressure greater than 20 mmHg; 2) Depth 33 mm: target chest compression depth of 33mm with standard American Heart Association epinephrine dosing; or 3) Depth 51 mm: target chest compression depth of 51 mm with standard American Heart Association epinephrine dosing. All animals received manual cardiopulmonary resuscitation guided by audiovisual feedback for 10 minutes before first shock. Measurements and Main Results: Forty-five-minute survival was higher in the coronary perfusion pressure-20 group (8 of 8) compared to depth 33mm (1 of 8) or depth 51 mm (3 of 8) groups; p equals to 0.002. Coronary perfusion pressures were higher in the coronary perfusion pressure-20 group compared to depth 33 mm (p = 0.004) and depth 51 mm (p = 0.006) and in survivors compared to nonsurvivors (p < 0.01). Total epinephrine dosing and defibrillation attempts were not different. Conclusions: Hemodynamic directed resuscitation targeting coronary perfusion pressures greater than 20 mmHg during 10 minutes of cardiopulmonary resuscitation for ventricular fibrillation cardiac arrest improves short-term survival, when compared to resuscitation with depth of compressions guided to 33 mm or 51 mm and standard American Heart Association vasopressor dosing. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Adequate coronary perfusion pressure (CPP) during cardiopulmonary resuscitation (CPR) is essential for establishing return of spontaneous circulation. The objective of this study was to compare short-term survival using a hemodynamic directed resuscitation strategy versus an absolute depth-guided approach in a porcine model of asphyxia-associated cardiac arrest. We hypothesized that a hemodynamic directed approach would improve short-term survival compared to depth-guided care. Methods: After 7min of asphyxia, followed by induction of ventricular fibrillation, 19 female 3-month old swine (31±0.4kg) were randomized to receive one of three resuscitation strategies: (1) hemodynamic directed care (CPP-20): chest compressions (CCs) with depth titrated to a target systolic blood pressure of 100mmHg and titration of vasopressors to maintain CPP>20mmHg; (2) depth 33mm (D33): target CC depth of 33mm with standard American Heart Association (AHA) epinephrine dosing; or (3) depth 51mm (D51): target CC depth of 51mm with standard AHA epinephrine dosing. All animals received manual CPR guided by audiovisual feedback for 10min before first shock. Results: 45-Min survival was higher in the CPP-20 group (6/6) compared to D33 (1/7) or D51 (1/6) groups; p =0.002. Coronary perfusion pressures were higher in the CPP-20 group compared to D33 (p =0.011) and D51 (p =0.04), and in survivors compared to non-survivors (p <0.01). Total number of vasopressor doses administered and defibrillation attempts were not different. Conclusions: Hemodynamic directed care targeting CPPs>20mmHg improves short-term survival in an intensive care unit porcine model of asphyxia-associated cardiac arrest. [Copyright &y& Elsevier]

Abstract: Introduction: The ventricular fibrillation (VF) waveform is dynamic and predicts defibrillation success. Quantitative waveform measures (QWMs) quantify these changes. Coronary perfusion pressure (CPP), a surrogate for myocardial perfusion, also predicts defibrillation success. The relationship between QWM and CPP has been preliminarily explored. We sought to further delineate this relationship in our porcine model and to determine if it is different between animals with/without ROSC (return of spontaneous circulation). Hypothesis: A relationship exists between QWM and CPP that is different between animals with/without ROSC. Methods: Utilizing a prior experiment in our porcine model of prolonged out-of-hospital VF cardiac arrest, we calculated mean CPP, cumulative dose CPP, and percent recovery of three QWM during resuscitation before the first defibrillation: amplitude spectrum area (AMSA), median slope (MS), and logarithm of the absolute correlations (LAC). A random effects linear regression model with an interaction term CPP*ROSC investigated the association between CPP and percent recovery QWM and how this relationship changes with/without ROSC. Results: For 12 animals, CPP and QWM measures (except LAC) improved during resuscitation. A linear relationship existed between CPP and percent recovery AMSA (coefficient 0.27; 95%CI 0.23, 0.31; p <0.001) and percent recovery MS (coefficient 0.80; 95%CI 0.70, 0.90; p <0.001). A linear relationship existed between cumulative dose CPP and percent recovery AMSA (coefficient 2.29; 95%CI 2.0, 2.56; p <0.001) and percent recovery MS (coefficient 6.68; 95%CI 6.09, 7.26; p <0.001). Animals with ROSC had a significantly “steeper” dose–response relationship. Conclusions: There is a linear relationship between QWM and CPP during chest compressions in our porcine cardiac arrest model that is different between animals with/without ROSC. [Copyright &y& Elsevier]

Abstract: Background: The fraction of cardiac arrest patients presenting with pulseless electrical activity is increasing, and it is likely that many of these patients have pseudo-electromechanical dissociation (P-EMD), a state in which there is residual cardiac contraction without a palpable pulse. The efficacy of cardiopulmonary resuscitation (CPR) with external chest compression synchronized with the P-EMD cardiac systole and diastole has not been fully evaluated. Hypothesis: During external chest compression in P-EMD, the coronary perfusion pressure (CPP) will be greater with systolic synchronization compared with diastolic phase synchronization. Methods: A porcine model of P-EMD induced by progressive hypoxia with peak aortic pressures targeted to 50mmHg was used. CPR chest compressions were performed by either load distributing band or vest devices. Paired 10s intervals of systolic and diastolic synchronization were performed randomly during P-EMD, and aortic, right atrial and CPP were compared. Results: Stable P-EMD was achieved in 8 animals, with 2.6±0.5 matched synchronization pairs per animal. Systolic synchronization was association with increases in relaxation phase aortic pressure (41.7±8.9mmHg vs. 36.9±8.2mmHg), and coronary perfusion pressure (37.6±11.7mmHg vs. 30.2±9.6mmHg). Diastolic synchronization was associated with an increased right atrial pressure (6.7±4.1mmHg vs. 4.1±5.7mmHg). Conclusion: During P-EMD, synchronization of external chest compression with residual cardiac systole was associated with higher CPP compared to synchronization with diastole. [Copyright &y& Elsevier]

Abstract: Introduction: The amount of myocardial perfusion required for successful defibrillation after cardiac arrest is unknown. Coronary perfusion pressure (CPP) is a surrogate for myocardial perfusion. One limited clinical study identifies a threshold of 15mmHg required for return of spontaneous circulation (ROSC). Our exploration of threshold and dose models of CPP during the initial bout of CPR indicates higher levels than previously demonstrated are required. CPP required for shock success throughout on-going resuscitation is unknown and other conceptual models of CPP have not been explored. Hypothesis: An array of conceptual models of CPP is associated with and predicts defibrillation success throughout resuscitation. Methods: Data from 6 porcine cardiac arrest studies were pooled. Mean and area under the curve (AUC) CPP were derived for 30-s epochs. Five conceptual models of CPP were analyzed: threshold, delta, cumulative delta, dose, and cumulative dose. Comparative statistics were performed with one-way ANOVA and two-tailed t-test. Regression models assessed CPP trends and prediction of ROSC. Results: For 316 defibrillation attempts in 124 animals, those resulting in ROSC (n =75) had significantly higher threshold, delta, cumulative delta, dose, and cumulative dose CPP than those without. All conceptual models except delta CPP had significantly different values across successive defibrillation attempts and all five models were significant predictors of ROSC, along with experimental design. Conclusions: Threshold, delta, cumulative delta, dose, and cumulative dose CPP predict individual defibrillation success throughout resuscitation. [Copyright &y& Elsevier]

Objectives. Vasopressors have been routinely used in cardiopulmonary resuscitation. Recent data show that terlipressin may restore blood pressure in asphyxial and prolonged arrests but its potential role in ventricular fibrillation (VF) remains unknown. The aim of this study was to compare coronary (CorPP) and cerebral (CPP) perfusion pressures achieved by terlipressin/adrenaline versus placebo/adrenaline in VF. Methods. Fourteen domestic pigs were randomly assigned into group A and B. After 5 min of untreated VF, compressiononly resuscitation was applied for 10 min, followed by advanced life support. Terlipressin in a single-dose of 30 μg.kg-1 was added to the first dose of adrenaline in group A, while placebo was given in group B. CorPP and CPP were calculated from right atrial, aortic and intracerebral pressures. Data were analyzed using repeated measurements ANOVA and a Fisher's protected LSD post hoc test. Results. Terlipressin/adrenaline maintained CorPP above 10 mmHg for 17.7 min longer than adrenaline alone (P=0.003) unable to prevent refractory hypotension. CorPP (mean±SD) measured at 35, 45, and 55 min after the onset of VF was 12 ± 4, 11 ± 6, and 10 ± 5 mmHg in the terlipressin group A; and 6 ± 4, 1 ± 5, and -1 ± 5 mmHg in placebo group B (P=0.03, <0.001, and <0.001). CPP measured at the same times was 23 ± 7, 20 ± 7, and 23 ± 7 mmHg in group A; and 13 ± 7, 6 ± 5, and 6 ± 7 mmHg in group B (P=0.01, <0.001, and <0.001). Conclusion. The study showed that a single dose of terlipressin, when added to adrenaline, was effective for achievement of higher vital organ perfusion pressures compared to adrenaline alone. [ABSTRACT FROM AUTHOR]

Background: The use of mechanical cardiopulmonary resuscitation (CPR) has great potential for the clinical setting. The purpose of present study is to compare the hemodynamics and ventilation during and after the load-distributing band CPR, versus the manual CPR in a porcine model of prolonged cardiac arrest, and to investigate the influence of rescue breathing in different CPR protocols. Methods: Sixty-four male pigs (n = 16/group), weighing 30 ± 2 kg, were induced ventricular fibrillation and randomized into four resuscitation groups: continuous load-distributing band CPR without rescue ventilation (C-CPR), load-distributing band 30:2 CPR (A-CPR), load-distributing band CPR with continuous rescue breathing (10/min) (V-CPR) or manual 30:2 CPR (M-CPR). Respiratory variables and hemodynamics were recorded continuously; blood gas was analyzed. Results: Tidal volume produced by compressions in the A-, C- and V-CPR groups were significantly higher compared with the M-CPR group (all p < 0.05). Coronary perfusion pressure of the V-CPR group was significantly lower than the C-CPR group (p < 0.01), but higher than the M-CPR group. The increasing of lung dead space after restoration of spontaneous circulation was significantly greater in the M-CPR group compared with the A-, C- and V-CPR groups (p < 0.01). Blood pH gradually decreased and was lower in the M-CPR group than that in the A-, Cand V-CPR groups (p < 0.01). PaO2 of the A-, C- and V-CPR groups were significantly higher and PaCO2 were significantly lower compared with the M-CPR (both p < 0.05). Cerebral performance categories were better in the A-, C- and V-CPR groups compared with the M-CPR group (p < 0.0001). Conclusions: The load-distributing band CPR significantly improved respiratory parameters during resuscitation by augmenting passive ventilation, and significantly improved coronary perfusion pressure. The volume of ventilation produced by the load-distributing band CPR was adequate to maintain sufficient gas exchange independent of rescue breathing. [ABSTRACT FROM AUTHOR]

Objective:Vasoactive drugs are used in cardiopulmonary resuscitation to increase vital organ perfusion. The aim of this study was to compare the haemodynamic effects of synergistically acting terlipressin and adrenaline vs. adrenaline alone in a porcine model of ventricular fibrillation (VF). Design: Randomized, double-blinded, placebo controlled experimental study. Setting: Department of Anaesthesiology and Intensive Care Medicine, University Hospital; Animal Research Laboratory, Faculty of Military Health Sciences Materials and methods: Fourteen domestic pigs were randomly assigned into group TER (n = 7) and ADR (n = 7). VF was induced using an intra-cardiac pacing lead. After 5 min of untreated arrest, compression-only resuscitation was applied for 10 min, followed by advanced life support. Terlipressin in a single-dose of 30 µg ⋅kg-1 was added to the first dose of adrenaline in group TER, while placebo was given in group ADR. Coronary (CorPP) and cerebral (CPP) perfusion pressures were calculated from the right atrial, aortic and intracerebral pressures. Data were analysed using repeated measurements ANOVA and a Fisher's protected LSD post hoc test. Results: Terlipressin/adrenaline maintained CorPP higher than 10 mm Hg for 17.7 min longer than adrenaline alone (P = 0.003). CorPP (mean ± SD) measured at 35, 45, and 55 min after the onset of VF was 12.2 ± 4.0, 11.0 ± 6.2, and 9.6 ± 4.5 mm Hg in group TER; and 5.8 ± 3.8, 0.6 ± 4.9, and -1.0 ± 4.5 mm Hg in group ADR (P = 0.03, < 0.001, and < 0.001). CPP measured at the same times was 23.0 ± 7.2, 20.4 ±6.9, and 23.1 ± 6.7 mm Hg in group TER; and 13.3 ± 6.5, 6.2 ± 5.3, and 5.6 ± 6.5 mm Hg in group ADR (P = 0.01, < 0.001, and < 0.001). Conclusion: A single dose of terlipressin, when added to adrenaline in cardiopulmonary resuscitation, was effective for achieving significantly higher cerebral and coronary perfusion pressures compared to adrenaline alone, which was unable to prevent severe refractory hypoperfusion. [ABSTRACT FROM AUTHOR]

To review the use of impedance threshold devices (ITD) during CPCR, their proposed mechanism of action, and their application in veterinary medicine. Data sources include scientific reviews and original research publications using the PubMed search engine with the following keywords: 'impedance threshold device' and 'resuscitation' and the Veterinary Information Network search function using the keywords 'impedance threshold device.' Studies in human medicine have demonstrated that the use of an ITD during CPCR in patients during out-of-hospital cardiac arrest improves coronary perfusion pressure and cerebral perfusion pressure. This improvement in vital organ blood flow results in increased cardiac output and faster return of spontaneous circulation. The use of an ITD has been studied in people and currently holds a class IIb level of recommendation according to the 2010 American Heart Association Guidelines for CPR and Emergency Cardiovascular Care. This device is recommended as a way to improve hemodynamics during CPCR by enhancing venous return and avoiding hyperventilation, thereby increasing the likelihood of a successful resuscitation. Multiple controlled studies using pigs with ventricular fibrillation induced cardiopulmonary arrest have demonstrated increased myocardial and cerebral perfusion with the use of an ITD. These studies have emphasized the importance of decreasing intrathoracic pressures during the decompression phase of CPCR and avoiding hyperventilation in order to maximize vital organ blood flow. Use of an ITD during CPCR in human and animal studies has demonstrated improved vital organ perfusion and faster return of spontaneous circulation. However, the majority of these studies have been carried out in people during out-of-hospital cardiac arrest and ventricular fibrillation cardiopulmonary arrest pig models. Further studies evaluating the use of an ITD during CPCR in the veterinary hospital setting are warranted. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Coronary perfusion pressure (CPP) during resuscitation from cardiac arrest has been shown to correlate with return of spontaneous circulation. Adrenergic blockade of beta-1 and alpha-1 receptors is common in the long-term management of ischemic heart disease and congestive heart failure. We sought to compare the CPP response to vasopressin vs. epinephrine in a swine model of cardiac arrest following pre-arrest adrenergic blockade. Methods: Eight anesthetized and instrumented swine were administered 0.1mg epinephrine and arterial pressure and heart rate response were measured. An infusion of labetalol was then initiated and animals periodically challenged with epinephrine until adrenergic blockade was confirmed. The left anterior descending coronary artery was occluded to produce ventricular fibrillation (VF). After 7min of untreated VF, mechanical chest compressions were initiated. After 1min of compressions, 1mg epinephrine was given while CPP was recorded. When CPP values had returned to pre-epinephrine levels, 40U of bolus vasopressin was given. Differences in CPP (post-vasopressor–pre-vasopressor) were compared within animals for the epinephrine and vasopressin response and with eight, non-adrenergically blocked, historical controls using Bayesian statistics with a non-informative prior. Results: The CPP response following epinephrine was 15.1mmHg lower in adrenergically blocked animals compared to non-adrenergically blocked animals (95% Highest Posterior Density [HPD] 2.9–27.2mmHg lower). CPP went up 18.4mmHg more following vasopressin when compared to epinephrine (95% HPD 8.2–29.1mmHg). The posterior probability of a higher CPP response from vasopressin (vs. epinephrine) in these animals was 0.999. Conclusions: Pre-arrest adrenergic blockade blunts the CPP response to epinephrine. Superior augmentation of CPP is attained with vasopressin under these conditions. [ABSTRACT FROM AUTHOR]

Abstract: Background: During manual chest compressions for cardiac arrest the waveforms of chest compressions are generally sinusoidal, whereas mechanical chest compression devices can have different waveforms, including trapezoidal. We studied the haemodynamic differences of such waveforms in a porcine model of cardiac arrest. Methods: Eight domestic pigs (weight 31±3kg) were anaesthetised and instrumented to continuously monitor aortic (AP) and right atrial pressure (RAP), carotid (CF) and cerebral cortical microcirculation blood flow (CCF). Coronary perfusion pressure (CPP) was calculated as the maximal difference between AP and RAP during diastole or decompression phase. After 4min of electrically induced ventricular fibrillation, mechanical chest compressions were performed with four different waveforms in a factorial design, and in randomized sequence for 3min each. Resulting differences are presented as mean with 95% confidence intervals. Results: Mean AP and RAP were higher with trapezoid than sinusoid chest compressions, difference 5.7 (0.7, 11) and 6.3 (2.1, 11)mmHg, respectively. Flow measured as CF and CCF was also improved with trapezoidal waveform, difference 14 (2.8, 26)ml/min and 11 (5.6, 17)% of baseline, respectively, with a parallel, non-significant (P =0.08) trend for CPP. Active vs. passive decompression to zero level improved CF, but without even a trend for CPP. Conclusion: Trapezoid chest compressions and active decompression to zero level improved blood flow to the brain. The compression waveform is an additional factor to consider when comparing mechanical and manual chest compressions and when comparing different compression devices. [ABSTRACT FROM AUTHOR]

Abstract: Background: The rationale for a compression to ventilation ratio of 3:1 in neonates with primary hypoxic, hypercapnic cardiac arrest is to emphasize the importance of ventilation; however, there are no published studies testing this approach against alternative methods. An extended series of cardiac compressions offers the theoretical advantage of improving coronary perfusion pressures and hence, we aimed to explore the impact of compression cycles of two different durations. Materials and methods: Newborn swine (n =32, age 12–36h, weight 2.0–2.7kg) were progressively asphyxiated until asystole occurred. Animals were randomized to receive compressions:ventilations 3:1 (n =16) or 9:3 (n =16). Return of spontaneous circulation (ROSC) was defined as a heart rate ≥100beatsmin−1. Results: All animals except one in the 9:3 group achieved ROSC. One animal in the 3:1 group suffered bradycardia at baseline, and was excluded, leaving us with 15 animals in each group surviving to completion of protocol. Time to ROSC (median and interquartile range) was 150s (115–180) vs. 148s (116–195) for 3:1 and 9:3, respectively (P =0.74). There were no differences in diastolic blood pressure during compression cycles or in markers of hypoxia and inflammation. The temporal changes in mean arterial blood pressure, heart rate, arterial blood gas parameters, and systemic and regional oxygen saturation were comparable between groups. Conclusion: Neonatal pigs with asphyxia-induced cardiac arrest did not respond to a compression:ventilation ratio of 9:3 better than to 3:1. Future research should address if alternative compression:ventilation ratios offer advantages over the current gold standard of 3:1. [Copyright &y& Elsevier]

Abstract: Patients with pulseless electrical activity or refractory ventricular fibrillation have a very bad prognosis. Coronary angiography and angioplasty may be required to restore an effective circulation, but this must be performed whilst chest compressions are continued. The LUCAS chest compression device is suitable for this purpose. So far there are no reports on the effect of this device on coronary circulation in humans. We monitored the coronary perfusion pressure assessed invasively as the difference between the diastolic pressures at the coronary ostium and right atrium, and compared these pressures with coronary flow graded using the TIMI scale in 6 patients. In 4 out of 6 we found a satisfactory coronary artery perfusion pressure and TIMI grade 3 flow (normal) on coronary angiography. Two of these patients survived the first 24h. Two patients did not have a satisfactory perfusion pressure and adequate flow rate was not seen. [Copyright &y& Elsevier]

Abstract: Aims: As the duration of untreated cardiac arrest increases, the effectiveness of standard therapies declines, and may be more harmful than helpful. We investigated the hemodynamic, metabolic and anti-inflammatory effects of Ringer''s ethyl pyruvate solution (REPS) versus Ringer''s solution (RS) in the acute model of prolonged porcine arrest. Methods: Seventeen mixed-breed swine were induced into ventricular fibrillation (VF) and left untreated for 8min. CPR was begun using a mechanical chest compression device at a rate of 100 per minute. At the onset of CPR, animals were randomly assigned to treatment with either 25mL/kg of RS or 25mL/kg of REPS containing 40mg/kg of ethyl pyruvate, infused over 5min in blinded fashion. CPR continued with administration of a drug cocktail at 2min and the first rescue shock was delivered at minute 13 of VF. Animals having ROSC were supported with standardized care for 2h. Results: Both groups had 100% ROSC and 100% 2-h survival. The REPS group exhibited higher median CPP (27.3mmHg) than the control group (16.5mmHg) by 3min of CPR, which continued throughout the duration of CPR (p =0.02). The median time to hypotension following ROSC was 9.64min in the REPS group and 7.25min in controls (p =0.04) and there was a non-significant trend of decreased use of vasopressors for the duration of resuscitation. There was no difference in systemic or cerebral metabolism between groups. There were non-significant trends of decreased IL-6, increased Il-10 and decreased mesenteric bacterial colony growth in those treated with REPS when compared to RS. Conclusions: The administration of REPS with CPR significantly improved intra- and post-resuscitation hemodynamics in this swine model of prolonged cardiac arrest, but did not definitely change the metabolic or inflammatory profile during the acute resuscitation period. [Copyright &y& Elsevier]

Abstract: Background: Cardiac arrest remains one of the leading causes of death worldwide. European Resuscitation Council Guidelines for Resuscitation 2005 recommend epinephrine for its treatment. Objectives: To estimate whether the administration of a vasodilatator such as nitroglycerin in combination with epinephrine during cardiopulmonary resuscitation would improve resuscitation outcome in an established model of ventricular fibrillation. Methods: Design: Prospective, randomized, blinded, controlled study. Setting: Animal research laboratory. Ventricular fibrillation was induced in 20 Landrace/Large-White pigs. It remained untreated for 8 min before attempting resuscitation precordial compressions, mechanical ventilation, and electrical defibrillation. Animals were randomized into two groups, 10 animals each. Group A received saline as placebo (10 mL dilution, bolus) and epinephrine (0.02 mg/kg). Group B received nitroglycerin (50 μg/kg) and epinephrine (0.02 mg/kg) during cardiopulmonary resuscitation. Electrical defibrillation was attempted after 10 min of ventricular fibrillation. Results: Four animals in group A restored spontaneous circulation in comparison to eight in Group B. Coronary perfusion pressure (p < 0.0001) was significantly increased in Group B during cardiopulmonary resuscitation. Conclusion: A vasodilatator, when administered in combination with a vasopressor such as epinephrine during cardiopulmonary resuscitation, increases coronary perfusion pressure. [Copyright &y& Elsevier]

Abstract: Objective: To explore in detail the expected magnitude of systemic perfusion pressure during standard CPR as a function of compression frequency for different sized people from neonate to adult. Method: A 7-compartment mathematical model of the human cardiopulmonary system – upgraded to include inertance of blood columns in the aorta and vena cavae – was exercised with parameters scaled to reflect changes in body weight from 1 to 70kg. Results: Maximal systemic perfusion pressure occurs at chest compression rates near 60, 120, 180, and 250/min for subjects weighing 70, 10, 3, and 1kg, respectively. Such maxima are predicted by analytical models describing the dependence of stroke volume on pump-filling time in the presence of blood inertia. This mathematical analysis reproduces earlier experimental results of Fitzgerald et al. in 10kg dogs. Conclusions: Fundamental geometry and physics suggest that the most effective chest compression frequency in CPR depends upon body size and weight. In neonates there is room for improvement at the top of the compression frequency scale at rates >120/min. In adults there may be benefit from lower compression frequencies near 60/min. [Copyright &y& Elsevier]

Objective. We sought to determine the effect of the preshock pause (PSP) on coronary perfusion pressure (CPP) decay and subsequent rescue shock (RS) outcome in porcine ventricular fibrillation (VF). Methods. Retrospective analysis of digitally recorded CPP tracings was performed. Ventricular fibrillation was electrically induced in all animals and resuscitation was standardized in all experiments. The first RS was delivered after an average of 10.8 minutes of VF (7.4 minutes of nontreatment and 3.4 minutes of resuscitation). The continuous CPP tracing segments, during the hands-off period prior to the first two rescue shocks, were imported into a spreadsheet and analyzed using descriptive statistics as well as univariate and multivariate statistical methods. The RS outcome for each animal was recorded as failed or return of spontaneous circulation (ROSC) (a systolic blood pressure of 80 mmHg or greater, sustained continuously for at least 1 minute). Results. We included 196 rescue shocks (120 first RS [RS1], 76 second RS [RS2]) from 120 swine. The mean CPP following the last compression before RS was 23.4 mmHg (standard error of the mean [SEM]: 1.3). The median PSP duration was 4.1 seconds (interquartile range [IQR]: 3.3, 6.1). The mean CPP just prior to RS was 7.6 mmHg (SEM: 0.6). Overall, the RS was successful (ROSC) in 57 of 120 (0.47 [95% confidence interval (CI): 0.38, 0.56]) attempts. Univariate results showed a counterintuitive positive correlation between PSP and maximum CPP for RS1 (r = 0.548, p < 0.001). Conclusion. During the resuscitation PSP in these porcine studies of prolonged VF, CPP dropped precipitously, but RS outcome was not adversely affected. [ABSTRACT FROM AUTHOR]

Summary: Aim of study: After cardiac arrest, uninterrupted chest compressions with restoration of myocardial blood flow facilitates restoration of spontaneous circulation. We recognized that this may best be accomplished with a mechanical device and especially so during transport. We therefore sought to develop a lightweight, portable chest compressor which may be carried on the belt or attached to the oxygen tank typically carried on the back of the first response rescuer. A miniaturized pneumatic chest compressor (MCC) weighing less than 2kg was developed and compared with a currently marketed “Michigan Thumper®”, which weighed 19kg. We hypothesized that the 2kg, low profile, portable device will be as effective as the standard pneumatic Thumper® for restoring circulation during CPR. Material and methods: Ventricular fibrillation was electrically induced in 10 domestic male pigs weighing 39±2kg, and untreated for 5min. Animals were then randomized to receive chest compressions with either the MCC or the Thumper®. After 5min of mechanical chest compression, defibrillation was attempted with a 150J biphasic shock. Coronary perfusion pressure (CPP) and end tidal PCO2 (EtPCO2) were measured by conventional techniques together with right carotid artery blood flow (CBF). Results: Four of five animals compressed with the Thumper® and each animal compressed with the MCC were successfully resuscitated. No significant differences in CPP, EtPCO2, CBF and post-resuscitation myocardial function were observed between groups. Resuscitated animals survived for more than 72h without neurological impairment. Conclusion: The low profile, 2kg miniaturized chest compressor is as effective as the conventional Thumper® in an experimental model of CPR. [Copyright &y& Elsevier]

1. The role of haemodynamic changes in left ventricular remodelling has been poorly investigated, especially in the context of volume overload cardiac hypertrophy. Low diastolic blood pressure and high left ventricular filling pressure are expected to affect coronary driving pressure negatively and thereby put in jeopardy subendocardial perfusion in particular. The consequences to global left ventricular remodelling remain undetermined. The aim of the present study was to investigate the role of coronary driving pressure in the development of subendocardial remodelling and the conceivable effects on cardiac function, using a rat model of aortocaval fistula. 2. Wistar rats, weighing 330–350 g, were submitted to aortocaval fistula (ACF group) or sham (control group) operations. Two haemodynamic measurements were determined following surgery, the initial measurement at week 1 and the final measurement at week 8. Cytokine expression, myeloperoxidase (MPO) activity, metalloproteinase expression and activity and fibrosis were assessed in two distinct left ventricular myocardial layers: the subendocardium (SE) and the non-subendocardium (non-SE). 3. The ACF group showed lower initial and final coronary driving pressure and lower final +dP/dt and –dP/dt compared with the control group. Multivariate analyses disclosed initial coronary driving pressure as the only haemodynamic parameter independently associated with SE fibrosis ( R2 = 0.76; P < 0.0001) and with +dP/dt ( R2 = 0.55; P = 0.0004) and –dP/dt ( R2 = 0.91; P < 0.0001). Matrix metalloproteinase (MMP)-2 expression and activity predominated in the SE of ACF animals, particularly in those with low coronary driving pressure. Increased levels of interleukin (IL)-6 and IL-1β also predominated in the SE of the ACF group. Otherwise, MPO activity and levels of tumour necrosis factor-α and IL-10 were similar in both groups. Final coronary driving pressure correlated with both the expression and activity of MMP-2. 4. Low coronary driving pressure early in the course of ACF determines SE damage and, by this mechanism, interferes negatively in left ventricular function. [ABSTRACT FROM AUTHOR]

Background: Cardiac arrest remains the leading cause of death in Western societies. Advanced Life Support guidelines propose epinephrine (adrenaline) for its treatment. The aim of this study was to assess whether a calcium sensitizer agent, such as levosimendan, administered in combination with epinephrine during cardiopulmonary resuscitation, would improve the initial resuscitation success. Methods: Ventricular fibrillation was induced in 20 Landrace/Large-White piglets, and left untreated for 8 min. Resuscitation was then attempted with precordial compressions, mechanical ventilation and electrical defibrillation. The animals were randomized into two groups (10 animals each): animals in Group A received saline as placebo (10 ml dilution, bolus) + epinephrine (0.02 mg/kg), and animals in Group B received levosimendan (0.012 mg/kg/10 ml dilution, bolus) + epinephrine (0.02 mg/kg) during cardiopulmonary resuscitation. Electrical defibrillation was attempted after 10 min of ventricular fibrillation. Results: Four animals in Group A showed restoration of spontaneous circulation and 10 in Group B ( P = 0.011). The coronary perfusion pressure, saturation of peripheral oxygenation and brain regional oxygen saturation were significantly higher during cardiopulmonary resuscitation in Group B. Conclusions: A calcium sensitizer agent, when administered during cardiopulmonary resuscitation, significantly improves initial resuscitation success and increases coronary perfusion pressure during cardiopulmonary resuscitation. [ABSTRACT FROM AUTHOR]

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