Is the tumour necrosis factor-alpha response following resuscitation gender dependent in the swine model?

Porcine blood cell and brain tissue energy metabolism: Effects of "early life stress"

Background: Early Life Stress (ELS) may exert long-lasting biological effects, e.g., on PBMC energy metabolism and mitochondrial respiration. Data on its effect on brain tissue mitochondrial respiration is scarce, and it is unclear whether blood cell mitochondrial activity mirrors that of brain tissue. This study investigated blood immune cell and brain tissue mitochondrial respiratory activity in a porcine ELS model. Methods: This prospective randomized, controlled, animal investigation comprised 12 German Large White swine of either sex, which were weaned at PND (postnatal day) 28-35 (control) or PND21 (ELS). At 20-24 weeks, animals were anesthetized, mechanically ventilated and surgically instrumented. We determined serum hormone, cytokine, and "brain injury marker" levels, superoxide anion (O₂ ^•¯) formation and mitochondrial respiration in isolated immune cells and immediate post mortem frontal cortex brain tissue. Results: ELS animals presented with higher glucose levels, lower mean arterial pressure. Most determined serum factors did not differ. In male controls, TNFα and IL-10 levels were both higher than in female controls as well as, no matter the gender in ELS animals. MAP-2, GFAP, and NSE were also higher in male controls than in the other three groups. Neither PBMC routine respiration and brain tissue oxidative phosphorylation nor maximal electron transfer capacity in the uncoupled state (ETC) showed any difference between ELS and controls. There was no significant relation between brain tissue and PBMC, ETC, or brain tissue, ETC, and PBMC bioenergetic health index. Whole blood O₂ ^•¯ concentrations and PBMC O₂ ^•¯ production were comparable between groups. However, granulocyte O₂ ^•¯ production after stimulation with E. coli was lower in the ELS group, and this effect was sex-specific: increased O₂ ^•¯ production increased upon stimulation in all control animals, which was abolished in the female ELS swine. Conclusion: This study provides evidence that ELS i) may, gender-specifically, affect the immune response to general anesthesia as well as O₂ ^•¯ radical production at sexual maturity, ii) has limited effects on brain and peripheral blood immune cell mitochondrial respiratory activity, and iii) mitochondrial respiratory activity of peripheral blood immune cells and brain tissue do not correlate.

Sex differences in acute cardiovascular care: a review and needs assessment

Despite significant progress in the care of patients suffering from cardiovascular disease, there remains a persistent sex disparity in the diagnosis, management, and outcomes of these patients. These sex disparities are seen across the spectrum of cardiovascular care, but, are especially pronounced in acute cardiovascular care. The spectrum of acute cardiovascular care encompasses critically ill or tenuous patients with cardiovascular conditions that require urgent or emergent decision-making and interventions. In this narrative review, the disparities in the clinical course, management, and outcomes of six commonly encountered acute cardiovascular conditions, some with a known sex-predilection will be discussed within the basis of underlying sex differences in physiology, anatomy, and pharmacology with the goal of identifying areas where improvement in clinical approaches are needed.

Sex-specific differences in survival after out-of-hospital cardiac arrest: a nationwide, population-based observational study

Background

It remains unclear whether men have more favorable survival outcomes after out-of-hospital cardiac arrest (OHCA) than women.

Methods

We reviewed a total of 386,535 patients aged ≥ 18 years with OHCA who were included in the Japanese registry from 2013 to 2016. The study endpoints were the rates of 1-month survival and neurologically intact survival (Cerebral Performance Category Scale score = 1 or 2). Based on age, the reviewed patients were categorized into the following eight groups: < 30, 30–39, 40–49, 50–59, 60–69, 70–79, 80–89, and ≥ 90 years. The survival outcomes in men and women were compared using hierarchical propensity score matching.

Results

The crude survival rate was significantly higher in men than in women in five groups: 30–39, 40–49, 50–59, 60–69, and 70–79 years (all P < 0.001). Similarly, the crude neurologically intact survival rate was significantly higher in men than in women in seven groups: < 30, 30–39, 40–49, 50–59, 60–69, 70–79, and 80–89 years (all P < 0.005). However, multivariate logistic regression analysis of each group revealed no significant sex-specific differences in 1-month survival outcomes (all P > 0.02). Moreover, after hierarchical propensity score matching, the survival outcomes did not significantly differ between both sexes (all P > 0.05).

Conclusions

No significant sex-specific differences were found in the rates of 1-month survival and neurologically intact survival after OHCA.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2547-x) contains supplementary material, which is available to authorized users.

Sports activity and paediatric out-of-hospital cardiac arrest at schools in Japan

BACKGROUND

Sudden cardiac death during exercise or sports is an important problem among young athletes and non-athletes. An understanding of the epidemiological features of sports-related out-of-hospital cardiac arrest (OHCA) among children is crucial for planning approaches for prevention and better outcomes of paediatric OHCAs. We assessed the characteristics and outcomes of sports-related OHCA among children at schools in Japan to prevent sports-related paediatric OHCA at schools.

METHODS

The Stop and Prevent cardIac aRrest, Injury, and Trauma in Schools (SPIRITS) is a nationwide, prospective, observational study linking databases of two nationally representative registries. Data on the characteristics and outcomes of sports-related paediatric OHCA at schools in Japan were obtained from these databases.

RESULTS

Between 2008 and 2015, 188 sports-related paediatric OHCAs due to presumed cardiac origin occurred. The greatest proportion of OHCA during or after sports was due to long-distance running (21.8%), followed by soccer/futsal (13.3%), basketball (12.2%), and baseball/rubber-ball baseball (11.2%). We also assessed the association between prehospital factors and one-month survival with favourable neurological outcome after sports-related OHCA. The proportions of ventricular fibrillation as the first documented rhythm, bystander cardiopulmonary resuscitation (CPR), and public-access defibrillation (PAD) were 87.8%, 87.2%, and 63.3%, respectively. Compared with the non-PAD group, the adjusted odds ratio (95% confidence interval) of the PAD group was 3.64 (1.78-7.45).

CONCLUSIONS

In Japan, 188 schoolchildren experienced OHCAs of cardiac origin occurring during or after sports activity at schools during the 8-year period. Increasing PAD is essential to enhance better neurological outcome after sports-related OHCA among students.

The impact of sex and age on neurological outcomes in out-of-hospital cardiac arrest patients with targeted temperature management

Background

There are conflicting data regarding sex-based differences in the outcomes of out-of-hospital cardiac arrest (OHCA) patients, and whether the specific sex advantage is age-specific remains unclear. We assessed the impact of the interactions between sex and age on the neurological outcomes of OHCA patients receiving targeted temperature management (TTM).

Methods

Data collected from 2007 to 2012 for a multicenter, registry-based study of the Korean Hypothermia Network were analyzed. We used a multivariate logistic regression model with an interaction term (age × sex) as the final model for the outcomes. To evaluate the association between sex and outcome in specific age groups, all patients were divided into specific age subgroups, and the adjusted ORs and 95% CIs of good neurological outcomes for males were calculated for each age group. Finally, the ORs of a good neurological outcome for the specific age groups compared with the 50- to 59-year-old group were calculated for both sexes.

Results

In the interaction analysis, age was a negative prognostic factor (OR, 0.95 [95% CI, 0.93-0.98]), whereas sex was not associated with neurological outcomes (OR, 3.74 [95% CI, 0.85–16.35]), and reproductive age in females (age, < 50 years) was also not associated with good neurological outcomes. After the patients were divided into five age groups, sex was not an independent predictor of neurological outcomes across all age groups. Patients of both sexes aged < 40 years had significantly better outcomes than patients in the 50- to 59-year-old group (males, OR, 4.03 [95% CI, 1.86–8.73]; females, OR, 10.34 [95% CI, 1.99–53.85]). Males aged ≥ 70 years had significantly poorer neurological outcomes than those in the 50- to 59-year-old group (OR, 0.15 [95% CI, 0.07–0.32]), but this outcome was not observed for females (OR, 0.78 [95% CI, 0.20–3.14]).

Conclusions

Sex did not influence the neurological outcomes of TTM-treated OHCA patients. In contrast to the outcomes in males, the neurological outcomes of females worsened from 18 to 59 years of age and then remained constant.

Contemporary animal models of cardiac arrest: A systematic review

AIM OF THE STUDY

Animal models are widely used in cardiac arrest research. This systematic review aimed to provide an overview of contemporary animal models of cardiac arrest.

METHODS

Using a comprehensive research strategy, we searched PubMed and EMBASE from March 8, 2011 to March 8, 2016 for cardiac arrest animal models. Two investigators reviewed titles and abstracts for full text inclusion from which data were extracted according to pre-defined definitions.

RESULTS

Search criteria yielded 1741 unique titles and abstracts of which 490 full articles were included. The most common animals used were pigs (52%) followed by rats (35%) and mice (6%). Studies favored males (52%) over females (16%); 17% of studies included both sexes, while 14% omitted to report on sex. The most common methods for induction of cardiac arrest were either electrically-induced ventricular fibrillation (54%), asphyxia (25%), or potassium (8%). The median no-flow time was 8min (quartiles: 5, 8, range: 0-37min). The majority of studies used adrenaline during resuscitation (64%), while bicarbonate (17%), vasopressin (8%) and other drugs were used less prevalently. In 53% of the studies, the post-cardiac arrest observation time was ≥24h. Neurological function was an outcome in 48% of studies while 43% included assessment of a cardiac outcome.

CONCLUSIONS

Multiple animal models of cardiac arrest exist. The great heterogeneity of these models along with great variability in definitions and reporting make comparisons between studies difficult. There is a need for standardization of animal cardiac arrest research and reporting.

Associations among gender, marital status, and outcomes of adult in-hospital cardiac arrest: A retrospective cohort study

AIM

To analyse the association between gender and outcomes of in-hospital cardiac arrest (IHCA) and the influences of age and marital status on the gender-based difference in clinical outcome.

METHODS

This retrospective observational study conducted in a single medical centre evaluated patients who had experienced IHCA from 2006 to 2014. Multivariate logistic regression analysis was used to study associations between independent variables and outcomes. Patients 18-49 years old were considered of reproductive age. The presence or absence of a legitimate spouse was retrieved from the family pedigree presented in the medical records. Reproductive age and marital status were each analysed as an interaction term with gender.

RESULTS

A total of 1524 patients, of which 598 were women (39.2%), were included in this study. There were 269 patients (17.7%) of reproductive age and 490 patients (32.2%) without a living spouse. Only 215 patients (14.1%) survived to hospital discharge. Among these, 110 patients (7.2%) demonstrated a favourable neurological status. Our analysis indicated that being female was inversely associated with a favourable neurological outcome (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.29-0.87; p=0.02). Being female without a living spouse was inversely associated with a favourable neurological outcome (OR, 0.43; 95% CI, 0.17-0.96; p=0.05). Neither female nor female-associated interaction terms were significantly associated with survival to hospital discharge.

CONCLUSION

Female patients with IHCA had worse neurological outcomes than their male counterparts, especially for women without a living spouse. However, survival outcome did not differ between genders.

Hyperglycaemia increases S100β after short experimental cardiac arrest

BACKGROUND

Hyperglycaemia is associated with aggravated ischaemic brain injury. The main objective of this study was to investigate the effects on cerebral perfusion of 5 min of cardiac arrest during hyperglycaemia and normoglycaemia.

METHODS

Twenty triple-breed pigs (weight: 22-29 kg) were randomised and clamped at blood glucose levels of 8.5-10 mM [high (H)] or 4-5.5 mM [normal (N)] and thereafter subjected to alternating current-induced 5 min-cardiac arrest followed by 8 min of cardiopulmonary resuscitation and direct current shock to restore spontaneous circulation.

RESULTS

Haemodynamics, laser Doppler measurements and regional venous oxygen saturation (HbO2) were monitored, and biochemical markers in blood [S100β, interleukin (IL)-6 and tumour necrosis factor (TNF)] quantified throughout an observation period of 3 h. The haemodynamics and physiological measurements were similar in the two groups. S100β increased over the experiment in the H compared with the N group (P < 0.05). IL-6 and TNF levels increased across the experiment, but no differences were seen between the groups.

CONCLUSIONS

The enhanced S100β response is compatible with increased cerebral injury by hyperglycaemic compared with normoglycaemic 5 min of cardiac arrest and resuscitation. The inflammatory cytokines were similar between groups.

Administration of amiodarone during resuscitation is associated with higher tumor necrosis factor-α levels in the early postarrest period in the swine model of ischemic ventricular fibrillation

To compare the early postarrest inflammatory cytokine response between animals administered amiodarone (AMIO) and lidocaine (LIDO) intra-arrest during resuscitation from ventricular fibrillation (VF). Domestic swine (n=32) were placed under general anesthesia and instrumented before spontaneous VF was induced by balloon occlusion of the left anterior descending coronary artery. After 7 min of VF, standard ACLS resuscitation was performed and animals were randomized to either bolus AMIO (5 mg/kg, n=13) or LIDO (1 mg/kg, n=14) for recurrent or refractory VF. A non-antiarrhythmic (n=5) was also used for comparison. Following return of spontaneous circulation (ROSC), tumor necrosis factor (TNF)-α levels were drawn at 30 and 60 min. Groups were comparable with respect to prearrest hemodynamics and resuscitation variables. In the postarrest period, the LIDO and non-antiarrhythmic group demonstrated virtually identical TNF-α response trajectories. However, TNF-α levels were significantly higher in AMIO- than LIDO-treated animals at 30 min (geometric mean 539 versus 240 pg/mL, 2.2-fold higher, 95% confidence interval [CI] 1.3-3.8-fold higher, P=0.003) and at 60 min (geometric mean 570 versus 204 pg/mL, 2.8-fold higher, 95% CI 1.1-7.0-fold higher, P=0.03). Significant differences in the postarrest TNF-α levels were observed between animals treated with AMIO as compared to those treated with LIDO. Improved rates of ROSC seen with AMIO may come at the expense of a heightened proinflammatory state in the postcardiac arrest period.

A comparison of etanercept vs. infliximab for the treatment of post-arrest myocardial dysfunction in a swine model of ventricular fibrillation

AIMS

To compare the effects of two TNF-α antagonists, etanercept and infliximab, on post-cardiac arrest hemodynamics and global left ventricular function (LV) in a swine model following ventricular fibrillation (VF).

METHODS

Domestic swine (n=30) were placed under general anesthesia and instrumented before VF was induced electrically. After 7 min of VF, standard ACLS resuscitation was performed. Animals achieving return of spontaneous circulation (ROSC) were randomized to immediately receive infliximab (5 mg/kg, n=10) or etanercept (0.3 mg/kg [4 mg/m(2)], n=10) or vehicle (250 mL normal saline [NS], n=10) and LV function and hemodynamics were monitored for 3 h.

RESULTS

Following ROSC, mean arterial pressure (MAP), stroke work (SW), and LV dP/dt fell from pre-arrest values in all groups. However, at the 30 min nadir, infliximab-treated animals had higher MAP than either the NS group (difference 14.4 mm Hg, 95% confidence interval [CI] 4.2-24.7) or the etanercept group (19.2 mm Hg, 95% CI 9.0-29.5), higher SW than the NS group (10.3 gm-m, 95% CI 5.1-15.5) or the etanercept group (8.9 gm-m, 95% CI 4.0-14.4) and greater LV dP/dt than the NS group (282.9 mm Hg/s, 95% CI 169.6-386.1 higher with infliximab) or the etanercep group (228.9 mm Hg/s, 95% CI 115.6-342.2 higher with infliximab).

CONCLUSIONS

Only infliximab demonstrated a beneficial effect on post cardiac arrest hemodynamics and LV function in this swine model. Etanercept was no better in this regard than saline.

TNF-α blockade improves early post-resuscitation survival and hemodynamics in a swine model of ischemic ventricular fibrillation

AIM OF THE STUDY

Inflammatory cytokines have been implicated in the pathophysiology of post cardiac arrest syndrome, including myocardial dysfunction and hypotension, often leading to multi-organ system dysfunction and death. We hypothesized that administration of infliximab after return of spontaneous circulation (ROSC) would ameliorate hypotension and myocardial dysfunction and prolong survival.

METHODS

Domestic swine were anesthetized and instrumented. Balloon occlusion of the LAD coronary artery just distal to the first septal perforator was performed and VF followed spontaneously in all animals. After 7 min, chest compressions, defibrillation, and standard ACLS resuscitation was performed. Animals achieving ROSC (N=32) were randomized to receive infliximab (5 mg/kg, n=16) or vehicle (250 mL normal saline, n=16) immediately post-ROSC and survival and hemodynamics were monitored for 3 h.

RESULTS

There were no differences in prearrest hemodynamic variables, TNF-α levels, or resuscitation variables between groups. Both groups demonstrated a time dependent decline in mean arterial pressure (MAP) and stroke work (SW) post-ROSC with a nadir at 1 h followed by recovery over hours 2 and 3. This decline was blunted in infliximab-treated swine (1-h between group difference in MAP 21 mm Hg, 95% CI 3-38 mm Hg and SW 6.7 gm-m, 95% CI 0.4-13 at 1 h). Left ventricular systolic dp/dt fell in the vehicle group (-437 mm Hg/s, 95% CI -183 to -690) but did not in the infliximab group. Tau rose only in the vehicle group (44 ms, 95% CI 1-87). Short-term survival was higher in the infliximab group (Kaplan-Meier p=0.022).

CONCLUSIONS

Blockade of TNF-α in the immediate post-ROSC period improved survival and hemodynamic parameters in this swine model of ischemic VF.

Molecular mechanisms of therapeutic hypothermia on neurological function in a swine model of cardiopulmonary resuscitation

OBJECTIVE

To explore the molecular mechanisms by which mild hypothermia following resuscitation improves neurological function in a porcine model of cardiac arrest.

METHODS

Thirty-three inbred Chinese Wuzhishan (WZS) minipigs were used. After 8 min of untreated ventricular fibrillation (VF), the surviving animals (n=29) were randomly divided into two groups including serum group (n=16) and molecular group (n=13). Serum group animals were used to measure porcine-specific tumour necrosis factor-alpha (TNF-α), interleukin (IL-6, IL-10), matrix metalloproteinase (MMP9), Aquaporin-4 (AQP4), tissue inhibitor to metalloproteinase-1 (TIMP1), neuron-specific enolase (NSE) and S100B at 0.5 h, 6 h, 12 h, 24 h and 72h recovery by enzyme-linked immunosorbent assay (ELISA). Molecular group animals were used to measure cerebral cortex messenger RNA (mRNA) and protein expression of nuclear factor-κB (NF-κB), MMP9 and AQP4 by real-time (RT) quantitative polymerase chain reaction (PCR) and Western blotting at 24 h and 72 h recovery. Animals were further divided into either normothermia or hypothermia groups. Hypothermia (33°C) was maintained for 12 h using an endovascular cooling device. Swine neurologic deficit scores (NDS) were used to evaluate neurological function at 24-h and 72-h recovery.

RESULTS

Twenty-nine of the 33 (87.9%) animals were successfully resuscitated. The hypothermia group exhibited higher survival rates at 24 h (75%) and 72 h (62.5%) compared to the normothermia group (37.5% and 25%, respectively). Hypothermia markedly inhibited expression of NF-κB, TNF-α, MMP9 and NSE, and promoted expression of TIMP1 (P<0.01). The mean NDS at 24-h and 72-h recovery was 112.5 and 61, respectively, in the hypothermic group, and 230 and 207.5, respectively, in the normothermia group.

CONCLUSION

Brain protection induced by hypothermia involves inhibition of inflammatory and brain edema pathways.

Investigation of the relationship between venticular fibrillation duration and cardiac/neurological damage in a rabbit model of electrically induced arrhythmia

BACKGROUND

To establish a simple, economic, and reliable alternating current (AC)-induced cardiac arrest (ACCA) model in rabbits for cardiopulmonary cerebral resuscitation research.

METHODS

Ventricular fibrillation was induced in 27 New Zealand rabbits by external transthoracic AC, which were randomly divided into three groups according to the duration of untreated ACCA (ACCA-3 minutes, ACCA-5 minutes, and ACCA-8 minutes). After ACCA, all animals received cardiopulmonary resuscitation for 2 minutes and subsequent defibrillation until return of spontaneous circulation (ROSC). The troponin I levels were measured at 4 hours after ROSC. Animals died spontaneously or were killed at 72 hours after ROSC. The hippocampus were removed and fixed in 3% formalin. TdT-mediated dUTP-biotin nick end labeling and Nissl stainings were performed in 10-μm thickness coronal sections. Furthermore, two rabbits (without induction of ventricular fibrillation, cardiopulmonary resuscitation, and defibrillation) served as normal control group.

RESULTS

Mean survival times after ROSC were 48.57 hours ± 24.70 hours, 18.0 hours ± 15.13 hours, and 3.88 hours ± 2.39 hours for groups ACCA-3 minutes, ACCA-5 minutes, and ACCA-8 minutes, respectively. Survival was significantly different between ACCA-3 minutes and other two groups (p = 0.002 and p = 0.01). Neuronal necrosis and apoptosis were found in the hippocampus CA1, CA2, and CA3 areas of group ACCA-3 minutes. In contrast, neuronal necrosis and TdT-mediated dUTP-biotin nick end labeling positive cells were fewer in control animals.

CONCLUSIONS

The rabbits in group ACCA-3 minutes had significant neuronal damage with apoptosis in hippocampus CA1, CA2, and CA3 areas at 72 hours after ROSC and survived longer than those in other groups. The model we describe may be a simple, economic, and reliable model for experimental investigation on cardiopulmonary cerebral resuscitation.

Cardiac function and the proinflammatory cytokine response after recovery from cardiac arrest in swine

Increased levels of cytokines have been reported after resuscitation from cardiac arrest. We hypothesized that proinflammatory cytokines, released in response to ischemia/reperfusion, increase following resuscitation and play a role in post-cardiac arrest myocardial dysfunction. Ventricular fibrillation (VF) was induced by coronary occlusion in 20 swine. After 7 min of VF, resuscitation was performed as per guidelines. Plasma levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 were measured 15 min after the start of resuscitation in all animals and at intervals of 6 h in resuscitated animals. Intravascular pressures and cardiac output (CO) were also recorded. TNF-alpha abruptly increased after resuscitation, peaking at 15 min following return of spontaneous circulation, and declined to baseline levels after 3 h. IL-1beta increased more slowly, reaching a maximum 2 h after reperfusion. IL-6 concentrations were not significantly different from control values at any time point. Males demonstrated greater elevations of TNF-alpha and IL-1beta than females. Stroke work was significantly depressed at all time points with a nadir at 15-30 min after reperfusion, corresponding to the peak TNF-alpha values. The anti-TNF-alpha antibody infliximab attenuated the decrease in myocardial function observed 30 min after reperfusion. TNF-alpha increases during recovery from cardiac arrest are associated with depression of left ventricle (LV) function. The effect of TNF-alpha can be attenuated by anti-TNF-alpha antibodies.

Infliximab attenuates early myocardial dysfunction after resuscitation in a swine cardiac arrest model

OBJECTIVE

Left ventricular dysfunction after successful cardiopulmonary resuscitation contributes to early death after resuscitation. Proinflammatory cytokines are known to decrease myocardial function, and tumor necrosis factor-alpha has been shown to increase after successful resuscitation. We hypothesized that blocking the effects of tumor necrosis factor-alpha with infliximab would prevent or minimize postresuscitation cardiac dysfunction.

DESIGN

Randomized, placebo-controlled comparative study.

SETTING

Large animal research laboratory.

SUBJECTS

Twenty-eight anesthetized and instrumented domestic male swine (Yorkshire and Yorkshire/Hampshire mix; weight, 35-45 kg).

INTERVENTIONS

Infusion of infliximab (5 mg/kg) or normal saline after resuscitation from ventricular fibrillation cardiac arrest.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic variables, indices of left ventricular function, and tumor necrosis factor-alpha were measured before and after 8 mins of cardiac arrest during the early postresuscitation period (3 hrs). Within 5 mins of restoration of spontaneous circulation, 14 animals received infliximab, 5 mg/kg, infused over 30 mins. Fourteen animals received an infusion of normal saline. Inotropes and vasopressors were not administered to either group after resuscitation. Tumor necrosis factor-alpha increased after restoration of circulation and remained elevated throughout the observation period. Differences between groups were not significant. Interleukin-1beta concentration did not change significantly during the observation period in either study group. Mean arterial pressure and stroke work were significantly greater in the infliximab group within 30 mins of resuscitation, and these differences were sustained throughout the 3-hr postresuscitation period. The effect of tumor necrosis factor-alpha blockade was evident only in animals with a significant increase (doubling) in plasma tumor necrosis factor-alpha at 30 mins after arrest.

CONCLUSION

Tumor necrosis factor-alpha plays a role in cardiac dysfunction after arrest and infliximab may attenuate or prevent postresuscitation myocardial dysfunction when administered immediately after resuscitation.

Hypocalcemia following resuscitation from cardiac arrest revisited

OBJECTIVE

Hypocalcemia associated with cardiac arrest has been reported. However, mechanistic hypotheses for the decrease in ionized calcium (iCa) vary and its importance unknown. The objective of this study was to assess the relationships of iCa, pH, base excess (BE), and lactate in two porcine cardiac arrest models, and to determine the effect of exogenous calcium administration on post-resuscitation hemodynamics.

METHODS

Swine were instrumented and VF was induced either electrically (EVF, n=65) or spontaneously, ischemically induced (IVF) with balloon occlusion of the LAD (n=37). Animals were resuscitated after 7 min of VF. BE, iCa, and pH, were determined prearrest and at 15, 30, 60, 90, 120 min after ROSC. Lactate was also measured in 26 animals in the EVF group. Twelve EVF animals were randomized to receive 1g of CaCl(2) infused over 20 min after ROSC or normal saline.

RESULTS

iCa, BE, and pH declined significantly over the 60 min following ROSC, regardless of VF type, with the lowest levels observed at the nadir of left ventricular stroke work post-resuscitation. Lactate was strongly correlated with BE (r=-0.89, p<0.0001) and iCa (r=-0.40, p<0.0001). In a multivariate generalized linear mixed model, iCa was 0.005 mg/dL higher for every one unit increase in BE (95% CI 0.003-0.007, p<0.0001), while controlling for type of induced VF. While there was a univariate correlation between iCa and BE, when BE was included in the regression analysis with lactate, only lactate showed a statistically significant relationship with iCa (p=0.02). Post-resuscitation CaCl(2) infusion improved post-ROSC hemodynamics when compared to saline infusion (LV stroke work control 8+/-5 gm vs 23+/-4, p=0.014, at 30 min) with no significant difference in tau between groups.

CONCLUSIONS

Ionized hypocalcemia occurs following ROSC. CaCl(2) improves post-ROSC hemodynamics suggesting that hypocalcemia may play a role in early post-resuscitation myocardial dysfunction.

The central nervous system cytokine response to global ischemia following resuscitation from ventricular fibrillation in a porcine model

AIM OF THE STUDY

Pro-inflammatory cytokines have been implicated as culprits in neurotoxicity following ischemia in small animal models of stroke. The aim of this study was to measure the central nervous system (CNS) cytokine response following resuscitation from ventricular fibrillation (VF) in a porcine model of cardiac arrest and global hypoxic ischemia.

METHODS

VF was induced electrically in 11 anesthetized swine. Following 7 min of untreated VF, animals were resuscitated. Cerebrospinal fluid (CSF) and serum was sampled prior to VF and at 60, 120, and 180 min post-resuscitation from which levels of TNF-alpha, IL-1 beta, and IL-6 were measured. Levels were also drawn in three sham pigs, instrumented but not fibrillated.

RESULTS

CSF levels of TNF-alpha rose following resuscitation and were associated with CSF levels of IL-1 beta (p=0.0002). CSF levels of all cytokines except TNF-alpha were associated with their serum counterparts.

CONCLUSIONS

Measurable increases in pro-inflammatory cytokines in the CSF follow resuscitation from cardiac arrest in this porcine model. The CNS response TNF-alpha and IL-1 beta are associated. However, serum levels of TNF-alpha did not seem to predict CSF levels in this study, consistent with the concept of immune privilege of the CNS.