Critical Care of the Post-Cardiac Arrest Patient

Evaluating the Impact of Point-of-Care Electroencephalography on Length of Stay in the Intensive Care Unit: Subanalysis of the SAFER-EEG Trial

BACKGROUND

Electroencephalography (EEG) is needed to diagnose nonconvulsive seizures. Prolonged nonconvulsive seizures are associated with neuronal injuries and deleterious clinical outcomes. However, it is uncertain whether the rapid identification of these seizures using point-of-care EEG (POC-EEG) can have a positive impact on clinical outcomes.

METHODS

In a retrospective subanalysis of the recently completed multicenter Seizure Assessment and Forecasting with Efficient Rapid-EEG (SAFER-EEG) trial, we compared intensive care unit (ICU) length of stay (LOS), unfavorable functional outcome (modified Rankin Scale score ≥ 4), and time to EEG between adult patients receiving a US Food and Drug Administration-cleared POC-EEG (Ceribell, Inc.) and those receiving conventional EEG (conv-EEG). Patient records from January 2018 to June 2022 at three different academic centers were reviewed, focusing on EEG timing and clinical outcomes. Propensity score matching was applied using key clinical covariates to control for confounders. Medians and interquartile ranges (IQRs) were calculated for descriptive statistics. Nonparametric tests (Mann-Whitney U-test) were used for the continuous variables, and the χ2 test was used for the proportions.

RESULTS

A total of 283 ICU patients (62 conv-EEG, 221 POC-EEG) were included. The two populations were matched using demographic and clinical characteristics. We found that the ICU LOS was significantly shorter in the POC-EEG cohort compared to the conv-EEG cohort (3.9 [IQR 1.9-8.8] vs. 8.0 [IQR 3.0-16.0] days, p = 0.003). Moreover, modified Rankin Scale functional outcomes were also different between the two EEG cohorts (p = 0.047).

CONCLUSIONS

This study reveals a significant association between early POC-EEG detection of nonconvulsive seizures and decreased ICU LOS. The POC-EEG differed from conv-EEG, demonstrating better functional outcomes compared with the latter in a matched analysis. These findings corroborate previous research advocating the benefit of early diagnosis of nonconvulsive seizure. The causal relationship between the type of EEG and metrics of interest, such as ICU LOS and functional/clinical outcomes, needs to be confirmed in future prospective randomized studies.

Effects of Targeted Hypercapnia on Mortality and Length of Stay of Post-cardiac Arrest Patients: A Systematic Review and Meta-Analysis

Therapeutic hypercapnia has been proposed as a potential strategy to enhance cerebral perfusion and improve outcomes in patients after cardiac arrest. However, the effects of targeted hypercapnia remain unclear. We conducted a systematic review and meta-analysis to evaluate the impact of hypercapnia compared to normocapnia on mortality and length of stay in post-cardiac arrest patients. We searched major databases for randomized controlled trials and observational studies comparing outcomes between hypercapnia and normocapnia in adult post-cardiac arrest patients. Data on in-hospital mortality and the ICU and hospital length of stay were extracted and pooled using random-effects meta-analysis. Five studies (two randomized controlled trials (RCTs) and three observational studies) with a total of 1,837 patients were included. Pooled analysis showed hypercapnia was associated with significantly higher in-hospital mortality compared to normocapnia (56.2% vs. 50.5%, OR 1.24, 95% CI 1.12-1.37, p<0.001). There was no significant heterogeneity (I2 = 25%, p = 0.26). No statistically significant differences were found for ICU length of stay (mean difference 0.72 days, 95% CI -0.51 to 1.95) or hospital length of stay (mean difference 1.13 days, 95% CI -0.67 to 2.93) between the groups. Sensitivity analysis restricted to mild hypercapnia studies did not alter the mortality findings. This meta-analysis did not find a mortality benefit with targeted hypercapnia compared to normocapnia in post-cardiac arrest patients. The results align with current guidelines recommending a normal partial pressure of arterial carbon dioxide (PaCO2) target range and do not support routinely targeting higher carbon dioxide levels in this setting.

Post-Cardiac Arrest: Mechanisms, Management, and Future Perspectives

Cardiac arrest is an important public health issue, with a survival rate of approximately 15 to 22%. A great proportion of these deaths occur after resuscitation due to post-cardiac arrest syndrome, which is characterized by the ischemia-reperfusion injury that affects the role body. Understanding physiopathology is mandatory to discover new treatment strategies and obtain better results. Besides improvements in cardiopulmonary resuscitation maneuvers, the great increase in survival rates observed in recent decades is due to new approaches to post-cardiac arrest care. In this review, we will discuss physiopathology, etiologies, and post-resuscitation care, emphasizing targeted temperature management, early coronary angiography, and rehabilitation.

Determinants of change in code status among patients with cardiopulmonary arrest admitted to the intensive care unit

BACKGROUND

Patients with cardiopulmonary arrest often have a poor prognosis, prompting discussion with families about code status. The impact of socioeconomic factors, demographics, medical comorbidities and medical interventions on code status changes is not well understood.

METHODS

This retrospective study included adult patients presenting with cardiac arrest to the intensive care unit of a hospital group between 5/1/2010-5/1/2020. We extracted chart data on socioeconomic factors, demographics, and medical comorbidities.

RESULTS

We identified 1,254 patients, of which 57.5% were males. Age was different across the groups with (61.2 ± 15.5 years) and without (61.2 ± 15.5 years) code status change (p= <0.0001). Code status was changed in 583 patients (46.5%). Among patients with code status change, the highest prevalence was White patients (34.8%), followed by African Americans (30.9%), and Hispanics (25.4%). Compared to patients who did not have a code status change, those with a change in code status were older (66.7 ± 14.8 years vs 61.2 ± 15.5 years). They were also more likely to receive vasopressor/inotropic support (74.6% vs 58.5%), and broad-spectrum antibiotics (70.3% vs 57.7%). Insurance status, ethnicity, religion, education, and salary did not lead to statistically significant changes in code status.

CONCLUSIONS

In patients with cardiopulmonary arrest, code status change was more likely to be influenced by the presence of medical comorbidities and medical interventions during hospitalization rather than by socioeconomic factors.

Hematological, Micro-Rheological, and Metabolic Changes Modulated by Local Ischemic Pre- and Post-Conditioning in Rat Limb Ischemia-Reperfusion

In trauma and orthopedic surgery, limb ischemia-reperfusion (I/R) remains a great challenge. The effect of preventive protocols, including surgical conditioning approaches, is still controversial. We aimed to examine the effects of local ischemic pre-conditioning (PreC) and post-conditioning (PostC) on limb I/R. Anesthetized rats were randomized into sham-operated (control), I/R (120-min limb ischemia with tourniquet), PreC, or PostC groups (3 × 10-min tourniquet ischemia, 10-min reperfusion intervals). Blood samples were taken before and just after the ischemia, and on the first postoperative week for testing hematological, micro-rheological (erythrocyte deformability and aggregation), and metabolic parameters. Histological samples were also taken. Erythrocyte count, hemoglobin, and hematocrit values decreased, while after a temporary decrease, platelet count increased in I/R groups. Erythrocyte deformability impairment and aggregation enhancement were seen after ischemia, more obviously in the PreC group, and less in PostC. Blood pH decreased in all I/R groups. The elevation of creatinine and lactate concentration was the largest in PostC group. Histology did not reveal important differences. In conclusion, limb I/R caused micro-rheological impairment with hematological and metabolic changes. Ischemic pre- and post-conditioning had additive changes in various manners. Post-conditioning showed better micro-rheological effects. However, by these parameters it cannot be decided which protocol is better.

Effect of Shenfu Injection () on Lactate and Lactate Clearance in Patients with Post-cardiac Arrest Syndrome: A Post Hoc Analysis of a Multicenter Randomized Controlled Trial

OBJECTIVE

To assess the effects of Shenfu Injection (, SFI) on blood lactate, and secondarily its effect on the lactate clearance (LC) in patients with post cardiac arrest syndrome (PCAS).

METHODS

The present study is a post hoc study of a randomized, assessor-blinded, controlled trial. Patients experienced in-hospital cardiac arrest between 2012 and 2015 were included in the predefined post hoc analyses. Of 1,022 patients enrolled, a total of 978 patients were allocated to the control group (486 cases) and SFI (492 cases) group, receiving standardized post-resuscitation care bundle (PRCB) treatment or PRCB combined with SFI (100 mL/d), respectively. Patients' serum lactate was measured simultaneously with artery blood gas, lactate clearance (LC) was calculated on days 1, 3, and 7 after admission and compared between groups. Lactate and LC were also compared between the survivors and non-survivors according to the 28-d mortality, as well as the survivors and non-survivors subgroups both in the SFI and control groups.

RESULTS

In both groups, compared with pre-treatment levels, mean arterial pressure (MAP) and PaO₂ were significantly improved on 1, 3, 7 d after treatment (P<0.05), while heart rate (HR) and blood glucose levels were significantly decreased on 1, 3 and 7 d after treatment (P<0.05). compared with control group, SFI treatment improved the values of MAP and PaO₂ (P<0.05), and significantly decreased the levels of HR and the blood glucose level on 3 and 7 d after treatment (P<0.05). Compared with the control group, lactate levels decreased faster in the SFI group versus the control group on 3 and 7 d (P<0.05). From initiation of treatment and the following 3 and 7 d, SFI treatment greatly increased the LC compared with that in the control group (P<0.05). Compared with survivors, non-survivors had higher admission lactate levels (7.3 ±1.1 mmol/L vs. 5.5 ±2.3 mmol/L; P<0.01), higher lactate levels on days 1, 3 and 7 (P<0.05), and LC were decreased significantly on 3 and 7 d after treatment (P<0.05). Similar results were also found both in the SFI and control groups between survivors and non-survivors subgroups.

CONCLUSION

SFI in combination with PRCB treatment is effective at lowering lactate level and resulted in increasing LC in a targeted population of PCAS patients.

Metformin prevents brain injury after cardiopulmonary resuscitation by inhibiting the endoplasmic reticulum stress response and activating AMPK-mediated autophagy

BACKGROUND AND AIMS

The neurological damage caused by cardiac arrest (CA) can seriously affect quality of life. We investigated the effect of metformin pretreatment on brain injury and survival in a rat CA/cardiopulmonary resuscitation (CPR) model.

METHODS AND RESULTS

After 14 days of pretreatment with metformin, rats underwent 9 minutes of asphyxia CA/CPR. Survival was evaluated 7 days after restoration of spontaneous circulation; neurological deficit scale (NDS) score was evaluated at days 1, 3, and 7. Proteins related to the endoplasmic reticulum (ER) stress response and autophagy were measured using immunoblotting. Seven-day survival was significantly improved and NDS score was significantly improved in rats pretreated with metformin. Metformin enhanced AMPK-induced autophagy activation. AMPK and autophagy inhibitors removed the metformin neuroprotective effect. Although metformin inhibited the ER stress response, its inhibitory effect was weaker than 4-PBA.

CONCLUSION

In a CA/CPR rat model, 14-day pretreatment with metformin has a neuroprotective effect. This effect is closely related to the activation of AMPK-induced autophagy and inhibition of the ER stress response. Long-term use of metformin can reduce brain damage following CA/CPR.

Post-Cardiac Arrest Syndrome

More than 356 000 out-of-hospital cardiac arrests occur in the United States annually. Complications involving post-cardiac arrest syndrome occur because of ischemic-reperfusion injury to the brain, lungs, heart, and kidneys. Post-cardiac arrest syndrome is a clinical state that involves global brain injury, myocardial dysfunction, macrocirculatory dysfunction, increased vulnerability to infection, and persistent precipitating pathology (ie, the cause of the arrest). The severity of outcomes varies and depends on precipitating factors, patient health before cardiac arrest, duration of time to return of spontaneous circulation, and underlying comorbidities. In this article, the pathophysiology and treatment of post-cardiac arrest syndrome are reviewed and potential novel therapies are described.

Protective effects of dexmedetomidine on hypoxia/reoxygenation injury in cardiomyocytes by regulating the CHOP signaling pathway

Hypoxia/reoxygenation (H/R) injury in myocardial cells occurs frequently during cardiac surgery and affects the prognosis of patients. The present study aimed to investigate the protective effects of dexmedetomidine (Dex) on H/R injury and its association with the C/EBP-homologous protein (CHOP) signaling pathway. An H/R model was constructed in H9C2 cells to investigate the effects of Dex on H/R injury. Cell viability, apoptosis and lactate dehydrogenase (LDH) levels were determined by MTT, flow cytometry and 2,4-dinitrophenylhydrazine colorimetric assays, respectively. The expression levels of inflammatory factors were measured by reverse transcription-quantitative PCR (RT-qPCR), and CHOP and glucose-regulated protein-78 (Grp78) expression levels were detected by RT-qPCR and western blotting. CHOP was overexpressed or knocked down to detect the cell viability, apoptosis, LDH level and the expression levels of inflammatory factors and Grp78. The results demonstrated that in the H/R group, cell viability was lower and apoptosis was higher, and that higher levels of LDH and inflammatory factors were present compared with those in the Dex+H/R group. Silencing of CHOP significantly reversed the H/R-reduced cell viability, high apoptotic rate and LDH levels, as well as the elevated expression levels of inflammatory factors and Grp78 caused by H/R injury, whereas the overexpression of CHOP inhibited cell viability and promoted apoptosis, elevated LDH level and expression of inflammatory factors and Grp78 compared with the negative control. Additionally, pretreatment with Dex significantly alleviated the H/R injury; thus, Dex may protect H9C2 cells against H/R induced cell injury, possibly by suppressing the CHOP signaling pathway.

Proportion of time spent in blood glucose range 70 to 140 mg/dL is associated with increased survival in patients admitted to ICU after cardiac arrest: A multicenter observational study

The benefit of any specific target range of blood glucose (BG) for post-cardiac arrest (PCA) care remains unknown.We conducted a multicenter retrospective study of prospectively collected data of all cardiac arrest patients admitted to the ICUs between 2014 and 2015. The main exposure was BG metrics during the first 24 hours, including time-weighted mean (TWM) BG, mean BG, admission BG and proportion of time spent in 4 BG ranges (<= 70 mg/dL, 70-140 mg/dL, 140-180 mg/dL and > 180 mg/dL). The primary outcome was hospital mortality. Multivariable logistic regression, Cox proportion hazard models and generalized estimating equation (GEE) models were built to evaluate the association between the different kinds of BG and hospital mortality.2,028 PCA patients from 144 ICUs were included. 14,118 BG measurements during the first 24 hours were extracted. According to TWM-BG, 9 (0%) were classified into the <= 70 mg/dL range, 693 (34%) into the 70 to 140 mg/dL range, 603 (30%) into the 140 to 180 mg/dL range, and 723 (36%) into the > 180 mg/dL range. Compared with BG 70 to 140 mg/dL range, BG 140 to 180 mg/dL range and > 180 mg/dL range were associated with higher hospital mortality probability. Proportion of time spent in the 70 to 140 mg/dL range was associated with good outcome (odds ratio 0.984, CI [0.970, 0.998], P = .022, for per 5% increase in time), and > 180 mg/dL range with poor outcome (odds ratio 1.019, CI [1.009, 1.028], P< .001, for per 5% increase in time). Results of the 3 kinds of statistical models were consistent.The proportion of time spent in BG range 70 to 140 mg/dL is strongly associated with increased hospital survival in PCA patients. Hyperglycemia (> 180 mg/dL) is common in PCA patients and is associated with increased hospital mortality.

Management of temperature control in post-cardiac arrest care: an expert report

Targeted temperature management (TTM) through induced hypothermia (between 32-36 ^oC) is currently regarded as a first-line treatment during the management of post-cardiac arrest patients admitted to the Intensive Care Unit (ICU). The aim of TTM is to afford neuroprotection and reduce secondary neurological damage caused by anoxia. Despite the large body of evidence on its benefits, the TTM is still little used in Spain. There are controversial issues referred to its implementation, such as the optimal target body temperature, timing, duration and the rewarming process. The present study reviews the best available scientific evidence and the current recommendations contained in the international guidelines. In addition, the study focuses on the practical implementation of TTM in post-cardiac arrest patients in general and cardiological ICUs, with a discussion of the implementation strategies, protocols, management of complications and assessment of the neurological prognosis.

Therapeutic strategies for ischemia reperfusion injury in emergency medicine

Ischemia reperfusion (IR) injury occurs when blood supply, perfusion, and concomitant reoxygenation is restored to an organ or area following an initial poor blood supply after a critical time period. Ischemia reperfusion injury contributes to mortality and morbidity in many pathological conditions in emergency medicine clinical practice, including trauma, ischemic stroke, myocardial infarction, and post‐cardiac arrest syndrome. The process of IR is multifactorial, and its pathogenesis involves several mechanisms. Reactive oxygen species are considered key molecules in reperfusion injury due to their potent oxidizing and reducing effects that directly damage cellular membranes by lipid peroxidation. In general, IR injury to an individual organ causes various pro‐inflammatory mediators to be released, which could then induce inflammation in remote organs, thereby possibly advancing the dysfunction of multiple organs. In this review, we summarize IR injury in emergency medicine. Potential therapies include pharmacological treatment, ischemic preconditioning, and the use of medical gases or vitamin therapy, which could significantly help experts develop strategies to inhibit IR injury.

Association between mild hypercapnia and hospital mortality in patients admitted to the intensive care unit after cardiac arrest: A retrospective study

BACKGROUND

Mild hypercapnia may increase cerebral oxygenation and attenuate cerebral injury in post-cardiac arrest patients. However, its association with hospital mortality has not been evaluated.

METHODS

We conducted a retrospective multi-center study of prospectively collected data of all cardiac arrest patients admitted to the ICU between 2014 and 2015. Different kinds of arterial carbon dioxide tension (PaCO₂), including time-weighted mean PaCO₂, mean PaCO₂, admission PaCO₂ and proportion of time spent in four PaCO₂ categories (hypocapnia, normocapnia, mild hypercapnia, and severe hypercapnia) were used to explore the association with outcomes. Restricted cubic splines models were built to evaluate the association between PaCO₂ and odds ratio for hospital mortality in overall population and subgroups of different pH levels (acidosis, normal pH and alkalosis).

RESULTS

2783 post-cardiac arrest patients in 150 ICUs were included. 933 (33.5%) were classified into the hypocapnia (PaCO₂ < 35 mmHg), 1088 (39.1%) into the normocapnia (35-45 mmHg), 472 (17%) into the mild hypercapnia (45-55 mmHg) and 390 (10.4%) into the severe hypercapnia (>55 mmHg) group. Compared with normocapnia, mild hypercapnia was not associated with higher hospital survival probability (OR 1.08 [95% CI 0.84-1.38, p = 0.558]). Time spent in the normocapnia was associated with good outcome (OR 0.98 [95% CI 0.97-0.99, p < 0.001], for every 5 percentage point increase in time), but mild hypercapnia was not (OR 1 [95% CI 0.98-1.01, p = 0.542]). Cox-proportional hazards models supported these findings. Associations between PaCO₂ and hospital mortality were not statistically significant in normal pH and alkalosis subgroups.

CONCLUSIONS

PaCO₂ has a U-shaped association with odds ratio for hospital mortality, with mild hypercapnia not having a higher hospital survival probability than normocapnia in post-cardiac arrest patients.

The optimal peripheral oxygen saturation may be 95-97% for post-cardiac arrest patients: A retrospective observational study

BACKGROUND

Current post-resuscitation guidelines recommend oxygen titration in adults with the return of spontaneous circulation after cardiac arrest. However, the optimal peripheral oxygen saturation (SpO₂) is still unclear for post-cardiac arrest care.

METHODS

We conducted a retrospective observational study of prospectively collected data of all cardiac arrest patients admitted to the intensive care units between 2014 and 2015. The main exposure was SpO₂, which were interfaced from bedside vital signs monitors as 1-min averages, and archived as 5-min median values. The proportion of time spent in different SpO₂ categories was included in separate multivariable regression models along with covariates. The primary outcome measure was hospital mortality and the proportion of discharged home as the secondary outcome was reported.

RESULTS

2836 post-cardiac arrest patients in ICUs of 156 hospitals were included. 1235 (44%) patients died during hospitalization and 818 (29%) patients discharged home. With multivariate regression analysis, the proportion of time spent in SpO₂ of ≤89%, 90%, 91%, and 92% were associated with higher hospital mortality. The proportion of time spent in SpO₂ of 95%, 96%, and 97% were associated with a higher proportion of discharged home outcome, but not associated with hospital mortality.

CONCLUSIONS

In this retrospective observational study, the optimal SpO₂ for patients admitted to the intensive care unit after cardiac arrest may be 95-97%. Further investigation is warranted to determine if targeting SpO₂ of 95-97% would improve patient-centered outcomes after cardiac arrest.

Management of Out-of-Hospital Cardiac Arrest Complicating Acute Coronary Syndromes

PURPOSE OF THE REVIEW

Out-of-hospital cardiac arrest (OHCA) complicating acute coronary syndromes (ACS) continues to carry a high rate of morbidity and mortality despite significant advances in EMS and interventional cardiology services. In this review, we discuss an evidence-based approach to the initial care and management of patients with OHCA complicating ACS from the pre-hospital response and initial resuscitation strategy, to advanced therapies such as coronary angiography, targeted-temperature management, neuro-prognostication, and care of the post-arrest patient.

RECENT FINDINGS

Early recognition of cardiac arrest and prompt initiation of bystander CPR are the most important factors associated with improved survival. A comprehensive and coordinated approach to in-hospital management, including PCI, targeted temperature management, critical care, and hemodynamic support represents a significant critical link in the chain of survival. OHCA complicated by ACS continues to be one of the most challenging disease states facing healthcare practitioners and maintains a high mortality rate despite substantial advancements in healthcare delivery. A comprehensive approach to in-hospital management and further exploration of novel interventions, including ECMO, may yield opportunities to optimize care and improve outcomes for cardiac arrest patients.