General health condition of patients hospitalized after an incident of in‐hospital or out‐of hospital sudden cardiac arrest with return of spontaneous circulation

Abstract Background Sudden cardiac arrest (SCA) is one of the main reasons for admission to the intensive care unit (ICU), which influences discharge in a good neurological state. Hypothesis To analyze patients who had recovery of spontaneous circulation (ROSC) during hospitalization in the ICU using the Glasgow Outcome Scale (GOS). Methods The study group comprised 78 patients after SCA (35 after out‐of‐hospital cardiac arrest [OHCA] and 43 after in‐hospital cardiac arrest [IHCA]) with ROSC who were admitted to the ICU of Regional Hospital No. 5 in Sosnowiec from January 1, 2016 to December 31, 2016. GOS was used to assess neurological status. Basic anthropological data, with, arterial blood pH, lactate concentration (LAC), and catecholamine treatment were also collected. Results In the study group, 32.1% (n = 25/78) of patients survived until ICU discharge and 30.8% (n = 24/78) until discharge from the hospital. SCA in cardiac mechanism was more common in OHCA than in the IHCA group (OHCA vs. IHCA: 85.7% vs. 62.8%, p = .02). There was no statistically significant difference between the two groups for neurological status assessed using GOS. There was no statistically significant difference between LAC or arterial blood pH and survival to ICU discharge, survival to hospital discharge, or mortality. The need for using catecholamines increased the mortality rate (GOS 1) (p < .001). Conclusions Most patients after RSOC were assigned to a group other than GOS 1, and 25% of all subjects belonged to GOS 4–5. Treatment with catecholamines was more common in patients who do not survive hospital or ICU discharge.


| INTRODUCTION
Sudden cardiac arrest (SCA) is one of the main reasons for admission to the intensive care unit (ICU), and it is defined as a sudden loss of mechanical heart activity. 1 Mortality in industrialized countries due to SCA is approximately 20%. 2 SCA is most common in patients with cardiological burden. 3 In the United States, approximately 395 000 cases of out-of-hospital cardiac arrest (OHCA) and approximately 200 000 cases of in-hospital cardiac arrest (IHCA) are found every year.
According to the European Resuscitation Council, the rate of incidence of SCA fluctuates approximately from 350 000 to 700 000 in Europe every year. 4 In 2018, the Polish state emergency medical system reported 26 738 cardiopulmonary resuscitation (CPR) attempts in OHCA (analysis of OHCA in Poland in a 12-month period).
In recent years, the rate of return of spontaneous circulation (ROSC) has increased because of improvement in the quality of medical services. After CPR, it is not only important to obtain ROSC and reduce mortality, but also survival to hospital discharge in a good neurological condition. 6 Several studies have shown that even the shortest delay in performing chest compressions can significantly reduce the chance of ROSC as well as survival in a good neurological condition. 4,7,8 Improving the quality of CPR was possible due to the latest advancements in medical technologies. The use of devices for automatic chest compressions or real-time monitoring of quality chest compressions is becoming an increasingly common method for improving CPR. It is used mainly to transport patients during CPR after SCA to a hospital as well as allow the performance of medical procedures, such as coronarography. 9,10 Additionally, the prediction of ROSC and neurological outcome after CPR depends on factors such as the time of CPR, total dosage of adrenaline during CPR, and the first electrocardiographic rhythm (ECG). 11 Ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) are very often the first ECG rhythms recorded in patients who suffered SCA. Defibrillation rhythms have been found to correlate positively with the increased possibility of ROSC compared with non-defibrillation rhythms (pulseless electrical activity and asystole). 12,13 In the case of shock-refractory pVT and VF, the use of amiodarone or lidocaine is recommended. Amiodarone inhibits the potassium channel, which prolongs the duration of the third phase of the action potential of conducting cells in the heart. In turn, lidocaine inhibits the sodium permeability of the neuron's membrane by blocking the sodium-potassium pump. These drugs have a similar effect on survival during CPR with shock-resistant pVT and VF. 14 During hypoxia, the cells of the cerebral cortex, which are the most sensitive to oxygen deficiency, begin to die by necrosis and apoptosis. Longer durations of hypoxia cause more brain damage 15 ; however, there are known methods to reduce brain damage after SCA, such as hypothermia or extracorporeal membrane oxygenation (ECMO). Targeted temperature management can lead not only to hospital discharge survival but also to discharge from the hospital in good neurological condition. Currently, several methods of inducing hypothermia after SCA are known, such as cold fluid infusion, external cooling, peritoneal lavage, and intravascular cooling. Nevertheless, the abovementioned medical techniques are very rare due to medical complications and their limited availability. [16][17][18][19] Utstein guidelines have been implemented for easily comparing CPR data of different countries and medical centers. They enable a uniform method of SCA data presentation. 20,21 According to American Heart Association report, the rate of survival to hospital discharge after OHCA among the adult population of the United States in the year 2015 fluctuated from 10.6% to 12.4%, whereas the survival rate after IHCA remained at 26.4% in 2016. 22,23 The data revealed by the European Resuscitation Council on the survival rate in Europe in the case of OHCA amounted to an average of 6.4% and in the case of IHCA between 3% and 27%. In Poland, survival depending on the time of contact with a healthcare professional in the hospital was approximately 36.3%. 4,5,[24][25][26] The Glasgow Outcome Scale (GOS), which was first used to assess neurological dysfunction and quality of life (QoL) after head injury 27 because of its simplistic use and is gaining more popularity for assessing the QoL after SCA with ROSC. 28 2 | METHODS All patients after SCA (either OHCA or IHCA) and successful resuscitation defined as ROSC before admission to the ICU of Regional Hospital No. 5 in Sosnowiec from January 1, 2016 to December 31, 2016 were included in the study.
The patient's health condition upon discharge from the ICU was assessed using the GOS. Furthermore, we analyzed additional factors that determine the prognosis after SCA with ROSC, such as arterial blood pH, lactate concentration (LAC) on admission to the ICU, and treatment with catecholamine during therapy. We also analyzed the time of treatment in the ICU, patient survival to discharge from ICU, time of treatment between discharge from ICU to discharge from the hospital, and patient survival to discharge from the hospital. The analysis of the significant difference in the mean value between groups concerning the type cardiac arrest (OHCA, IHCA) was performed using Student's t-test or Mann-Whitney U test, whereas, in GOP, the pH and LAC groups were subjected to one-way analysis of variance or the Kruskal-Wallis test.
The qualitative data are presented as percentages, and results for dependent variables were obtained using the χ 2 test, whereas comparisons among groups were performed using the Difference Fraction Significance test with Bonferroni correction for multiple comparisons.
p-value <.05 was considered statistically significant. Informed consent was obtained from all of the patients recruited.

| RESULTS
Seventy-nine patients who suffered SCA with ROSC were admitted to the ICU; one patient was excluded from the final analysis due to the sudden death after admission before any gasometric blood samples were taken. Therefore, 78 patients after an episode of SCA with ROSC who were admitted to the ICU of Regional Hospital No. 5 in Sosnowiec from January 2016 to December 2016 were included in the final statistical analysis. The patients were divided into two groups according to the setting of SCA: OHCA-35 patients (44.9%) and IHCA-43 patients (55.1%). No statistically significant differences in anthropometric data were recorded between the two analyzed groups of patients (Table 1).
A higher proportion of patients after OHCA in cardiac mechanism vs. the proportion of patients after IHCA (85.7% vs. 62.8%), as well as a lower proportion of patients after OHCA in non-cardiac mechanism vs. the proportion of patients after IHCA (13.3% vs. 37.2%), were observed; both above-mentioned differences were statistically significant (p < .05). Between the groups analyzed (IHCA vs. OHCA), no statistically significant differences were observed for the survival rate to hospital discharge, duration of hospitalization after ICU discharge, or duration of hospitalization in the ICU. Similarly, neither the necessity of catecholamines nor the level of pH and LAC on admission to the ICU appeared to be statistically significant (Table 2).
Dependence between the health condition, which was measured by the GOS scale and mechanism and place of cardiac arrest, pH value, and LAC on admission to the ICU, as well as the administration of catecholamines during the treatment, time of hospitalization in the ICU and after discharge from the ICU, and survival to discharge from the hospital were analyzed in detail. The need for treatment with catecholamines during hospitalization in the ICU was indeed more frequent among the group of deceased patients 49 (94.2%) in contrast to other groups 2 (33.3%) for GOS 2-3 and 9 (50%) for GOS 4-5, respectively.
Surprisingly, the patient's sex significantly influenced their health condition. The health condition of males was better than that of females.
The proportion of deaths was comparable in both (Table 3). Additional analysis was also performed for survival rate and the duration of hospitalization (Table 4).
Observations also showed a statistically significant influence of the administration of catecholamines during the treatment on the ward and patient death. In addition, survival in the whole treatment cycle was higher among the patients in whom catecholamines were not administered.

| DISCUSSION
Our study aimed to assess patients hospitalized in the ICU after IHCA and OHCA using the GOS scale and to assess factors affecting discharge.
A higher rate of survival to hospital discharge was demonstrated by analyzing the data of patients after IHCA from the Danderyd Hospital in Sweden between January 1, 2012 and December 31, 2017.
The result of this study was 34%. Other studies in Sweden showed that the survival rate of patients was significantly reduced by 28% in the 70-79 age group, 20% in the 80-89 group, and 14% in the ≥ 90 age group. 29 In the University Hospital in Cork, 27% survival to hospital discharge after IHCA was reported in 2011. 30 Sandroni et al., in their analysis, reported a survival rate to hospital discharge in various hospitals after IHCA that ranged from 0% to 42%, with the most common rate being approximately 20%, which is lesser than the value found in our results (27%). 31 In our center, the rate of survival to hospital discharge for patients after OHCA in 2016 was 34%, which was slightly lower than that in 2015 (37%). 28 However, this is a much higher result than the one described in England in 2014, which was 7.9% 38  The above-mentioned surprisingly high survival rate accompanied by the mean patient age of 64.8 years (higher than in the current analysis) was probably due to the profile of the hospital and round-theclock availability of the specialists at the cardiac center.
In the Netherlands, an analysis on patients admitted after OHCA Comparison of our results with results from other centers allowed us to observe significant differences in the rate of survival to discharge from the hospital.
The impact on survival probably involved many factors, including the severity of the patients' condition and cardiac arrest mechanism.
In this analysis, we only included patients who developed ROSC Studies from the Świętokrzyskie Province indicate that 43.3% of patients survived hospital discharge, which is greater than that in our study (34.3%). These differences may be due to the nature of the hospital; our hospital is a trauma center. Moreover, their analysis does not consider the neurological condition, and as we know, discharge in a good neurological state is as important as discharge from the hospital. 39 Numerous retrospective analyses were performed to determine factors influencing the survival rate of patients admitted to ICUs after SCA of different mechanisms with ROSC.
In a similar retrospective analysis performed at our center in 2015, 28  than in patients who are in a better condition (GOS 4-5). In our previous study, the results were similar. 28 In addition, the median duration of hos- However, the hospital profile (trauma center), groups with fewer patients, and different etiologies of SCA can influence the results.
The main limitation of the current study is that some patients with a poor neurological condition who were admitted to the ICU after SCA with ROSC died in the ICU because of prolonged treatment complications. 28

| CONCLUSIONS
In summary, in the analyzed patient groups, treatment in the ICU in 2016, the survival to ICU discharge after SCA with ROSC averaged 32.1% to ICU discharge and 30.8% to hospital discharge. A total of 24.4% of patients survived with good health conditions. A significant statistical difference was not observed in ICU and hospital discharge independently depending on the site of SCA (OHCA vs. IHCA) or SCA mechanism (cardiogenic vs. non-cardiogenic). We did not observe a statistically significant difference between the health condition and the mechanism or site of SCA. The need for treatment with catecholamines was correlated with increased mortality (GOS 1). Patients with severe conditions had a prolonged duration of hospitalization in the ICU compared with patients having good health conditions (GOS 4-5).