Cardiac arrest survivors treated with or without mild therapeutic hypothermia: performance status and quality of life assessment

Observer-reported cognitive decline in out-of-hospital cardiac arrest survivors and its association with long-term survivor and relative outcomes

AIM

Long-term cognitive decline after out-of-hospital cardiac arrest (OHCA) is still poorly understood. This study describes long-term observer-reported cognitive decline among Danish OHCA survivors, including differences in years since the event, and investigates characteristics and self-reported outcomes associated with observer-reported cognitive decline.

METHODS

Adults who survived an OHCA from 2016 to 2019, and their relatives, completed the national DANish Cardiac Arrest Survivorship survey. Relatives completed the Informant Questionnaire on Cognitive Decline in the Elderly, Cardiac Arrest version (IQCODE-CA), the Hospital Anxiety and Depression Scale (HADS) and the World Health Organisation-Five Well-being index; and survivors completed the Two Simple Questions (everyday activities and mental recovery), the Modified Fatigue Impact Scale, HADS, and the Short World Health Organisation Disability Assessment Schedule 2.0. Potential associations between survivor characteristics and the IQCODE-CA were investigated using a multivariable logistic regression model. Self-reported outcomes among survivors and relatives, and the association with IQCODE-CA scores were investigated using separate logistic regression models.

RESULTS

Total median IQCODE-CA score was 3.04 (IQR: 3.00-3.27), with 47% having possible cognitive decline (score ≥ 3.04), consistent across time groups. Increasing age (OR 0.98, 95% CI: 0.97-0.99) and worse self-reported mental and physical outcomes for survivors and relatives, except 'everyday activities' were significantly associated with possible cognitive decline among survivors.

CONCLUSIONS

Nearly half of OHCA survivors may suffer long-term cognitive decline. Worse self-reported mental and physical outcomes among survivors and their relatives are associated with potential cognitive decline emphasising the need for post-OHCA care to include systematic neurocognitive assessment, tailored support and effective rehabilitation.

Does time heal fatigue, psychological, cognitive and disability problems in people who experience an out-of-hospital cardiac arrest? Results from the DANCAS survey study

AIMS

Out-of-hospital cardiac arrest (OHCA) survivors may suffer short-term fatigue, psychological, cognitive and disability problems, but we lack information on the proportion of survivors with these problems in the long-term. Hence, we investigated these problems in survivors 1-5 years post-OHCA and whether the results are different at different time points post-OHCA.

METHODS

All adults who survived an OHCA in Denmark from 2016 to 2019 were identified using the Danish Cardiac Arrest Registry and invited to participate in a survey between October 2020 and March 2021. The survey included the Modified Fatigue Impact Scale, Hospital Anxiety and Depression Scale, "Two simple questions" (everyday activities and mental recovery), and the 12-item World Health Organisation Disability Assessment Schedule 2.0. To investigate results at different time points, survivors were divided into four time-groups (12-24, 25-36, 37-48 and 49-56 months post-OHCA). Differences between time-groups were determined using the Kruskall-Wallis test for the mean scores and Chi-square test for the proportion of survivors with symptoms.

RESULTS

Total eligible survey population was 2116, of which 1258 survivors (60 %) responded. Overall, 29 % of survivors reported fatigue, 20 % anxiety, 15 % depression, and 27 % disability. When survivors were sub-divided by time since OHCA, no significant difference was found on either means scores or proportion between time groups (p = 0.28 to 0.88).

CONCLUSION

Up to a third of survivors report fatigue, anxiety, depression, reduced mental function and disability 1-5 years after OHCA. This proportion is the same regardless of how much time has passed supporting early screening and tailored post-OHCA interventions to help survivors adapt to their new situation.

The Effect of Mild Hypothermia on Nogo-A and Neurological Function in the Brain after Cardiopulmonary Resuscitation in Rats

ObjectiveWe investigated the dynamic changes of Nogo-A protein in brain and the effects of mild therapeutic hypothermia (MTH) on its expression after cardiopulmonary resuscitation (CPR). Methods: Western-blotting and neurological scoring of 45 rats subjected to cardiac arrest and CPR with and without MTR were performed to investigate the changes in the expression of Nogo-A protein in the hippocampus and cortex over a period of time ranging from 6 h to 72 h after restoration of spontaneous circulation (ROSC). Results: Nogo-A expression levels were increased at 6 h after CPR in the hippocampus and cortex, peaked at 24 h in the cortex, and at 48 h in the hippocampus. The expression of Nogo-A in the MTR group was significantly lower at 12 h (p < 0.05) compared to those with no MTR after ROSC. Conclusions: MTR blunts the expression of Nogo-A protein in the hippocampus and cortex after cardiac arrest and resuscitation, and MTR may provide cerebral protection after ischemia.

Hypothermia selectively protects the anterior forebrain mesocircuit during global cerebral ischemia

Hypothermia is an important protective strategy against global cerebral ischemia following cardiac arrest. However, the mechanisms of hypothermia underlying the changes in different regions and connections of the brain have not been fully elucidated. This study aims to identify the metabolic nodes and connection integrity of specific brain regions in rats with global cerebral ischemia that are most affected by hypothermia treatment. ¹⁸F-fluorodeoxyglucose positron emission tomography was used to quantitatively determine glucose metabolism in different brain regions in a rat model of global cerebral ischemia established at 31–33°C. Diffusion tensor imaging was also used to reconstruct and explore the brain connections involved. The results showed that, compared with the model rats established at 37–37.5°C, the rat models of global cerebral ischemia established at 31–33°C had smaller hypometabolic regions in the thalamus and primary sensory areas and sustained no obvious thalamic injury. Hypothermia selectively preserved the integrity of the anterior forebrain mesocircuit, exhibiting protective effects on the brain during the global cerebral ischemia. The study was approved by the Institutional Animal Care and Use Committee at Capital Medical University (approval No. XW-AD318-97-019) on December 15, 2019.

Case study: A positive cognitive outcome following an out-of-hospital cardiac arrest

OBJECTIVE

Time is critical with any out of hospital cardiac arrest (OHCA). The possibility of brain cell death increases, and the likelihood of a "good" outcome decreases with time. The most prominent impairments involve memory and attentional difficulties. Limited research and few cases have shown positive cognitive results following an OHCA to the extent that this case study depicts.

METHOD

The current case study presents a right-handed male in his late 40s, with master's and law degrees, and a high-level functioning in the workplace who experienced an OHCA. He was treated for his OHCA and subsequently underwent neuropsychological testing less than 2 months following his hospital discharge.

RESULTS

Expected results suggest impairments in key cognitive areas; however, a neuropsychological exam less than 2-months post-incident, testing pre-morbid IQ, overall cognitive ability, processing speed, attention, executive functioning, language, visuospatial abilities, and memory; each showing normal or better results. Additionally, self and collateral report questionnaires examining cognitive and emotional functioning reported no difficulties and no major changes since his cardiac arrest.

CONCLUSIONS

We speculate that this patient's exceptional outcome might be due to his cognitive reserve, and the immediateness of his intervention (5-10 min of CPR and return-of-spontaneous-circulation from an AED shock) and use of a saline cooling procedure upon arrival to the hospital. Overall, we highlight a patient with a remarkable cognitive outcome, utilizing data from neuropsychological testing within 2-months post-incident, and propose protective factors in neuropsychological functioning following an OHCA.

Hypothermia causes platelet activation in the human spleen

BACKGROUND

Accidental hypothermia results in various dysfunctions in the human body. Additionally, coagulation disorder can lead to a life-threatening condition. We previously demonstrated that platelets stored in the spleen were activated and thus triggered coagulation disorder in a mouse model of hypothermia. In the present study, we wanted to investigate if this phenomenon in mice also occurs in humans as a reaction to hypothermia.

METHODS

We analyzed splenic tissue collected from 22 deceased subjects who have died from hypothermia. These samples were compared with 22 control cases not exposed to cold environment. We performed immunohistochemical staining for CD61 (a marker of all platelets) and CD62P (a marker of activated platelets). We also evaluated the morphology of platelets in the spleen with scanning electron microscopy.

RESULTS

Immunohistochemical analysis revealed no significant changes in the amounts of CD61-positive platelets between the hypothermia and control cases. However, the hypothermia cases contained abundant CD62P-positive platelets compared with those of the control cases. Immunohistochemical analysis also revealed that the activated platelets formed aggregates and adhered to splenic sinusoidal endothelial cells in the hypothermia cases. However, we observed no significant fibrin formation around the activated platelets.

CONCLUSIONS

Hypothermia resulted in splenic platelet activation, which may be used as a postmortem marker of hypothermia. The release of activated platelets from the spleen into to circulation upon rewarming may promote coagulation disturbances.

Prevalence and experience of fatigue in survivors of critical illness: a mixed-methods systematic review

We conducted a mixed methods systematic review to investigate the prevalence, experience and management of fatigue in survivors of critical illness. We identified 76 studies investigating fatigue or vitality in adults discharged from an intensive care unit and split the extracted data into three datasets: vitality scores from the Short Form Health Survey-36 (n = 54); other quantitative data (n = 19); and qualitative data (n = 9). We assessed methodological quality using critical appraisal skills programme tools. We adopted a segregated approach to mixed-methods synthesis. In a final step, we attributed combined results to one of four qualitative themes: prevalence and severity; contributing factors; impacts on quality of life; and assessment and management. Prevalence of fatigue ranged from 13.8 to 80.9%. Short Form Health Survey-36 vitality scores were commonly used as a marker of fatigue. Vitality scores reached a nadir approximately one month following ICU discharge (mean (SD) 56.44 (32.30); 95%CI 52.92-59.97). They improved over time but seldom reached reference population scores. Associated biological, disease-related and psychological factors included age, poor pre-morbid status, sleep and psychological disturbance. Qualitative data highlight the profound negative impact of fatigue on survivors' quality of life. Survivors seldom had any information provided on the potential impact of fatigue. No fatigue assessment tools specific to critical illness or evidence-based interventions were reported. Fatigue is highly prevalent in survivors of critical illness, and negatively impacts recovery. Further research on developing fatigue assessment tools specifically for critically ill patients and evaluating the impact of pharmacological and non-pharmacology interventions is needed.

Hypothermia-induced activation of the splenic platelet pool as a risk factor for thrombotic disease in a mouse model

BACKGROUND

Hypothermia, either therapeutically induced or accidental (ie, an involuntary decrease in core body temperature to <35°C), results in hemostatic disorders. However, it remains unclear whether hypothermia enhances or inhibits coagulation, especially in severe hypothermia. The present study evaluated the thrombocytic and hemostatic changes in hypothermic mice.

METHODS

C57Bl/6 mice were placed at an ambient temperature of -20°C under general anesthesia. When the rectal temperature decreased to 15°C, 10 mice were immediately euthanized, while another 10 mice were rewarmed, kept in normal conditions for 24 hours, and then euthanized. These treatments were also performed in 20 splenectomized mice.

RESULTS

The hypothermic mice had adhesion of CD62P-positive platelets with high expression of von Willebrand factor (vWF) in their spleens, while the status of the peripheral platelets was unchanged. Furthermore, the plasma levels of platelet factor 4 (PF4) and pro-platelet basic protein (PPBP), which are biomarkers for platelet degranulation, were significantly higher in hypothermic mice than in control mice, indicating that hypothermia activated the platelets in the splenic pool. Thus, we analyzed these biomarkers in asplenic mice. There was no increase in either PF4 or PPBP in splenectomized hypothermic mice. Additionally, the plasma D-dimer elevation and microthrombosis were caused in rewarmed mice, but not in asplenic rewarmed mice.

CONCLUSIONS

Our results indicate that hypothermia leads to platelet activation in the spleen via the upregulation of vWF, and this activation causes hypercoagulability after rewarming.

Neuropsychological Outcome following Resuscitation after Out-of-Hospital Cardiac Arrest: A One-Year Follow-Up

A 61-year-old woman survived resuscitation after out-of-hospital cardiac arrest. The heterogeneity of the resulting cognitive impairments and the recovery over a one-year period are presented, highlighting the need for standardized neuropsychological testing even after short cardiac arrests and for effective treatment both out of hospital and in hospital.

Mapping the Knowledge Structure of Neonatal Hypoxic-Ischemic Encephalopathy Over the Past Decade: A Co-word Analysis Based on Keywords

The aim of this study was to analyze the knowledge structure and report the evolution of hypoxic-ischemic encephalopathy research over the past decade based on co-word analysis. Scientific publications focusing on neonatal hypoxic-ischemic encephalopathy were searched from the Web of Science database (January 2005 to December 2014). The keywords from these articles were extracted, and a knowledge network based on these keywords was built using Ucinet6.212 and NetDraw2.084 software. A total of 1892 papers were included, and 39 high-frequency keywords were defined. "HIE" and "neonate" located at the center of the knowledge network. Etiology and pathogenesis, clinical manifestation, and therapy were researched more widely in the network than other aspects of hypoxic-ischemic encephalopathy. This co-word analysis provides an overview of neonatal hypoxic-ischemic encephalopathy research and suggests that the etiology, clinical manifestation, and therapy of hypoxic-ischemic encephalopathy have become research cores over the past decade.

Association between therapeutic hypothermia and long-term quality of life in survivors of cardiac arrest: A systematic review

OBJECTIVES

Therapeutic hypothermia (TH) has increasingly become a part of the current standard of care for treating patients with cardiac arrest (CA). However, little is known regarding the association between TH and long-term quality of life (QoL) in adult survivors of CA. We conducted a systematic review to investigate the association between TH implementation and long-term QoL outcomes in adult survivors of CA following hospital discharge.

METHODS

We systematically searched MEDLINE and Cochrane databases to identify randomized and observational studies from January 2005 to January 2016 investigating the relationship between TH implementation immediately post-CA and long-term QoL in CA survivors post-hospital discharge.

RESULTS

We included 9 studies with a total of 801 patients. Six of these were prospective cohort studies, 2 were substudies of randomized controlled trials, and 1 was a retrospective cohort study. Six studies included patients only with out-of-hospital CA while 3 included patients with both in-hospital and out-of-hospital CA. There was marked between-study heterogeneity with respect to study population, TH implementation, and QoL assessment tool. TH was not associated with long-term QoL in this population.

CONCLUSIONS

In this systematic review, the included studies do not suggest any association between TH implementation in CA with long-term QoL in CA survivors. Further larger scale studies are needed to investigate the sustainability of TH effects long term in this patient population.