Methods
The study was approved by the Ethics Committee for the Non-Invasive
Research at the Gulhane Health Sciences University (Committee IRB
approval number: 2020/06-decision no: 2020/126).
Study design and patient selection
All non-traumatic cardiac arrest patients admitted to the emergency
department from November 1 2016 to January 31 2020 were screened in the
electronic patient management system (FONET®, Information Technology
Incorporation, Turkey). Patient charts were screened, as well as an
electronic patient management system. Patients who were younger than 18
years and who had missing information were excluded. All non-traumatic
CA patients without the exclusion criteria were included in the study
(Figure-1).
Age, gender, complete blood count (CBC) parameters of the patients,
routine biochemistry measurements, coagulation parameters, and blood gas
analysis, cardiac markers, whether ROSC was achieved or not, the initial
rhythm [Asystole, Ventricular Fibrillation (VF), Pulseless Ventricular
Tachycardia (VT), Pulseless Electrical Activity (PEA)], duration of
CPR (min), and hospital admission status were recorded. The patients
were divided into two groups as patients in whom ROSC was achieved (ROSC
group) or those in whom ROSC was not achieved (non-ROSC group). ROSC was
defined as spontaneous circulation and was achieved longer than 20 min.
The ROSC group was also divided into two subgroups as survivors
(discharged from the hospital) and non-survivors (mortality occurred
during hospital stay).
Power analysis
The sample size was calculated with an alpha value of 0.05, 80% power,
an enrollment ratio of 1, and COHb values of 0.9 in group 1 (ROSC group)
and 0.54 in group 2 (no-ROSC group), yielding that 26 patients in either
group making a total of 52 participants would be included in the study
(17,18).
Laboratory analysis
By the protocol of the emergency service where the study was conducted,
blood samples are taken simultaneously for CBC, routine biochemistry,
blood gas analysis, cardiac markers, and coagulation parameters within
the first 4 mins of the onset of CPR.
CBC (Beckman Coulter Unicell DxH 800, CA 92821 USA), blood gas
parameters (Radiometer ABL800 FLEX, 2700 Bronshoj Denmark), routine
biochemistry (Beckman Coulter AU680, CA 92821 USA), cardiac Troponin
(cTn), creatine kinase MB isoenzymes (CKMB) (Beckman Coulter DxI 800
Access immunoassay systems, CA 92821 USA), PTZ-INR, and D-Dimer (Sysmex
CS-2500, Kobe 651-0073 Japan) were measured in the emergency
biochemistry laboratory.
Statistical analysis
The categorical variables were presented as frequency and percentages.
Continuous variables were presented as mean ± standard deviation. The
Kolmogorov Smirnov test was used for testing whether the variables were
distributed normally. Student’s t-test was used for binary comparison of
continuous variables conforming to the normal distribution, Mann-Whitney
U test for non-compliant ones, and Chi-square test for comparison of
categorical data. A p-value of < 0.05 was considered
statistically significant. The statistical analysis software was SPSS
Statistics for Windows, version 22.0 (SPSS Statistics for Windows,
Version 22.0. IBM Corp., Armonk, N.Y., USA).