J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 16, Number 12, December 2024, pages 578-588

The Impact on Patient Prognosis of Changes to the Method of Notifying Staff About Accepting Patients With Out-of-Hospital Cardiac Arrest

Figure 1. Comparison of communication systems used to gather staff in the ER in preparation for accepting OHCA patients. (a) Situation before introduction of the Code Blue system. (b) After the introduction of the Code Blue system. For example, if a patient with OHCA will arrive in 10 min, the ER nurse will twice broadcast “Code Blue, Code Blue, 10 minutes” via the Code Blue system. ER: emergency room; OHCA: out-of-hospital cardiac arrest; PHS: personal handy phone system.

Figure 2. Patient enrollment. Participants were consecutive OHCA patients (including patients with return of spontaneous circulation before arrival at the hospital) who were admitted to our hospital before and after introduction of the Code Blue system. All participants were admitted during the daytime shift. Patients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group were admitted from March 30, 2022, to March 22, 2023. OHCA: out-of-hospital cardiac arrest.

Figure 3. Changes in the number of medical staff present in the emergency room when out-of-hospital cardiac arrest patients arrived. CB: Code Blue system.

Figure 4. Changes in ROSC, survival to discharge, and social reintegration rates after introduction of the CB. ROSC: return of spontaneous circulation; CB: Code Blue system.

**Table 1.** Main Roles of Medical Staff When the CB Is Activated
	Main roles
The general roles of these staff members have been clarified in advance. ER: emergency room; CB: Code Blue system; COVID-19: coronavirus disease 2019.
Emergency physician	Tracheal intubation, blood sampling, ultrasound examination, sheath insertion into arterial and venous line
Support physicians (non-emergency physicians, who are not in the ER when CB activated)	Tracheal intubation, blood sampling, ultrasound examination, sheath insertion into arterial and venous line
ER chief nurse	Timekeeper, chest compression device attachment, family contact/response
ER nurses	Recording, drug preparation/administration, drip route creation, intravenous line insertion
Support nurses	Tracheal intubation assistance, sheath insertion assistance, drug administration
Bed management nurse	Preparation for securing bed, support for families
Clinical engineers (medical engineers)	Priming, connecting, and setting up of arterial line
Radiology technicians	Portable X-ray preparation, computed tomography preparation
Medical technologists	COVID-19 antigen test, ultrasound examination, direct counter shock preparation, blood collection assistance, specimen transportation
Medical clerks	Reception support, administrative liaison, family support

Table 1. Main Roles of Medical Staff When the CB Is Activated

Main roles

The general roles of these staff members have been clarified in advance. ER: emergency room; CB: Code Blue system; COVID-19: coronavirus disease 2019.

Emergency physician

Tracheal intubation, blood sampling, ultrasound examination, sheath insertion into arterial and venous line

Support physicians (non-emergency physicians, who are not in the ER when CB activated)

Tracheal intubation, blood sampling, ultrasound examination, sheath insertion into arterial and venous line

ER chief nurse

Timekeeper, chest compression device attachment, family contact/response

ER nurses

Recording, drug preparation/administration, drip route creation, intravenous line insertion

Support nurses

Tracheal intubation assistance, sheath insertion assistance, drug administration

Bed management nurse

Preparation for securing bed, support for families

Clinical engineers (medical engineers)

Priming, connecting, and setting up of arterial line

Radiology technicians

Portable X-ray preparation, computed tomography preparation

Medical technologists

COVID-19 antigen test, ultrasound examination, direct counter shock preparation, blood collection assistance, specimen transportation

Medical clerks

Reception support, administrative liaison, family support

**Table 2.** Characteristics of Patients With OHCA Admitted Before and After Introduction of the Code Blue System
	Before CB group^a, N = 30	After CB group^a, N = 30	P
^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; CPR: cardiopulmonary resuscitation; IQR: interquartile range; SD: standard deviation; OHCA: out-of-hospital cardiac arrest.
Age (years), mean (SD)	81 (10)	79 (13)	0.456
Sex, male, n (%)	17 (57)	17 (57)	1.000
Hypertension, n (%)	22 (73)	24 (80)	0.549
Diabetes mellitus, n (%)	17 (57)	17 (57)	1.000
Cardiovascular disease, n (%)	5 (17)	5 (17)	1.000
Brain disease, n (%)	8 (27)	7 (23)	0.770
Dementia, n (%)	16 (53)	14 (47)	0.613
Treatment before arriving at the hospital
Bystander CPR, n (%)	5 (17)	5 (17)	1.000
Adrenaline administration in the ambulance, n (%)	0 (0)	2 (7)	0.155
Amount of adrenaline used in ER (mg), median (IQR)	5.0 (3.0 - 7.0)	4.0 (3.0 - 5.0)	0.053
Time from arrival at hospital to administration of adrenaline (min), median (IQR)	4.0 (3.0 - 4.75)	3.0 (3.0 - 5.0)	0.588

Table 2. Characteristics of Patients With OHCA Admitted Before and After Introduction of the Code Blue System

Before CB group^a, N = 30

After CB group^a, N = 30

^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; CPR: cardiopulmonary resuscitation; IQR: interquartile range; SD: standard deviation; OHCA: out-of-hospital cardiac arrest.

Age (years), mean (SD)

81 (10)

79 (13)

0.456

Sex, male, n (%)

17 (57)

1.000

Hypertension, n (%)

22 (73)

24 (80)

0.549

Diabetes mellitus, n (%)

17 (57)

1.000

Cardiovascular disease, n (%)

5 (17)

1.000

Brain disease, n (%)

8 (27)

7 (23)

0.770

Dementia, n (%)

16 (53)

14 (47)

0.613

Treatment before arriving at the hospital

Bystander CPR, n (%)

5 (17)

1.000

Adrenaline administration in the ambulance, n (%)

0 (0)

2 (7)

0.155

Amount of adrenaline used in ER (mg), median (IQR)

5.0 (3.0 - 7.0)

4.0 (3.0 - 5.0)

0.053

Time from arrival at hospital to administration of adrenaline (min), median (IQR)

4.0 (3.0 - 4.75)

3.0 (3.0 - 5.0)

0.588

**Table 3.** Changes in ROSC Rate With the Introduction of the CB According to the Patients’ Location at Onset of OHCA, the Presence or Absence of Pre-Hospital Care, the Causes, and ECG Findings
	ROSC rate for each condition	P
^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; ECG: electrocardiogram; OHCA: out-of-hospital cardiac arrest; CPR: cardiopulmonary resuscitation; PEA: pulseless electrical activity; ROSC: return of spontaneous circulation; VF: ventricular fibrillation.
Location at onset of OHCA
Outdoors (n = 9), n (%)	0/3 (0)	2/6 (33)	0.316
Elderly care facility (n = 15), n (%)	2/10 (20)	1/5 (20)	1
At home (n = 36), n (%)	4/17 (24)	6/19 (32)	0.603
Pre-hospital care
Bystander CPR (n = 10), n (%)	1/5 (20)	2/5 (40)	0.545
Adrenaline administration in the ambulance (n = 2), n (%)	0/0 (0)	1/2 (50)	-
Cause of OHCA
Aspiration (n = 8), n (%)	1/3 (33)	4/5 (80)	0.244
Cardiovascular disease (n = 14), n (%)	0/7 (0)	3/7 (43)	0.055
Pulmonary disease (n = 12), n (%)	2/6 (33)	1/5 (20)	0.662
Cerebrovascular disease (n = 3), n (%)	0/0 (0)	0/3 (0)	-
Suicide, self-harm (n = 6), n (%)	1/4 (25)	0/2 (0)	0.541
Others (n = 17), n (%)	1/9 (11)	1/8 (13)	-
ECG findings at the time of OHCA detection
Asystole (n = 45), n (%)	3/22 (14)	5/23 (22)	0.489
PEA (n = 13) or VF (n = 2), n (%)	3/8 (38)	4/7 (57)	0.483
Cardiovascular disease-related PEA (n = 3) or VF (n = 2), n (%)	0/0 (0)	5/5 (100)	-

Table 3. Changes in ROSC Rate With the Introduction of the CB According to the Patients’ Location at Onset of OHCA, the Presence or Absence of Pre-Hospital Care, the Causes, and ECG Findings

ROSC rate for each condition

Before CB group^a

After CB group^a

^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; ECG: electrocardiogram; OHCA: out-of-hospital cardiac arrest; CPR: cardiopulmonary resuscitation; PEA: pulseless electrical activity; ROSC: return of spontaneous circulation; VF: ventricular fibrillation.

Location at onset of OHCA

Outdoors (n = 9), n (%)

0/3 (0)

2/6 (33)

0.316

Elderly care facility (n = 15), n (%)

2/10 (20)

1/5 (20)

At home (n = 36), n (%)

4/17 (24)

6/19 (32)

0.603

Pre-hospital care

Bystander CPR (n = 10), n (%)

1/5 (20)

2/5 (40)

0.545

Adrenaline administration in the ambulance (n = 2), n (%)

0/0 (0)

1/2 (50)

Cause of OHCA

Aspiration (n = 8), n (%)

1/3 (33)

4/5 (80)

0.244

Cardiovascular disease (n = 14), n (%)

0/7 (0)

3/7 (43)

0.055

Pulmonary disease (n = 12), n (%)

2/6 (33)

1/5 (20)

0.662

Cerebrovascular disease (n = 3), n (%)

0/0 (0)

0/3 (0)

Suicide, self-harm (n = 6), n (%)

1/4 (25)

0/2 (0)

0.541

Others (n = 17), n (%)

1/9 (11)

1/8 (13)

ECG findings at the time of OHCA detection

Asystole (n = 45), n (%)

3/22 (14)

5/23 (22)

0.489

PEA (n = 13) or VF (n = 2), n (%)

3/8 (38)

4/7 (57)

0.483

Cardiovascular disease-related PEA (n = 3) or VF (n = 2), n (%)

0/0 (0)

5/5 (100)

**Table 4.** Factors Affecting ROSC in Patients With OHCA
	ROSC (+), N = 15	ROSC (-), N = 45	P
CPR: cardiopulmonary resuscitation; OHCA: out-of-hospital cardiac arrest; ROSC: return of spontaneous circulation; ER: emergency room; IQR: interquartile range; SD: standard deviation.
Age (years), mean (SD)	83 (10)	79 (12)	0.265
Sex, male, n (%)	11 (73)	23 (51)	0.137
Number of staff in the ER
Total, mean (SD)	12.2 (5.9)	9.6 (5.0)	0.095
Physicians, mean (SD)	3.4 (1.6)	2.6 (1.6)	0.076
Nurses, mean (SD)	4.9 (2.9)	3.9 (2.3)	0.194
Co-medical staff, mean (SD)	3.9 (1.9)	3.1 (1.5)	0.088
Pre-hospital care
Bystander CPR, n (%)	3 (20)	7 (16)	0.695
Adrenaline administration in the ambulance, n (%)	1 (7)	1 (2)	0.415
Care in ER
Amount of adrenaline used (mg), median (IQR)	2.0 (1.5 - 3.0)	5.0 (4.0 - 6.0)	< 0.001
Time from arrival at hospital to administration of adrenaline (min), median (IQR)	3.0 (2.5 - 4.0)	4.0 (3.0 - 5.0)	0.188

Table 4. Factors Affecting ROSC in Patients With OHCA

ROSC (+), N = 15

ROSC (-), N = 45

CPR: cardiopulmonary resuscitation; OHCA: out-of-hospital cardiac arrest; ROSC: return of spontaneous circulation; ER: emergency room; IQR: interquartile range; SD: standard deviation.

Age (years), mean (SD)

83 (10)

79 (12)

0.265

Sex, male, n (%)

11 (73)

23 (51)

0.137

Number of staff in the ER

Total, mean (SD)

12.2 (5.9)

9.6 (5.0)

0.095

Physicians, mean (SD)

3.4 (1.6)

2.6 (1.6)

0.076

Nurses, mean (SD)

4.9 (2.9)

3.9 (2.3)

0.194

Co-medical staff, mean (SD)

3.9 (1.9)

3.1 (1.5)

0.088

Pre-hospital care

Bystander CPR, n (%)

3 (20)

7 (16)

0.695

Adrenaline administration in the ambulance, n (%)

1 (7)

1 (2)

0.415

Care in ER

Amount of adrenaline used (mg), median (IQR)

2.0 (1.5 - 3.0)

5.0 (4.0 - 6.0)

< 0.001

Time from arrival at hospital to administration of adrenaline (min), median (IQR)

3.0 (2.5 - 4.0)

4.0 (3.0 - 5.0)

0.188

**Table 5.** Comparison of Patients With OHCA and ROSC Who Were Treated Before and After the Introduction of the CB
ROSC cases (n = 15)	Before CB group^a (n = 6)	After CB group^a (n = 9)	P
^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; OHCA: out-of-hospital cardiac arrest; ROSC: return of spontaneous circulation; IQR: interquartile range; SD: standard deviation.
Amount of adrenaline used until ROSC (mg), mean (SD)	4.5 (4.3)	1.9 (1.1)	0.098
Time from arrival at hospital to ROSC (min), median (IQR)	11.5 (10.25 - 28.5)	11.0 (4.0 - 12.0)	0.287
Time from arrival at hospital to administration of adrenaline (min), median (IQR)	3.5 (3.0 - 4.0)	3.0 (1.0 - 5.0)	0.763

Table 5. Comparison of Patients With OHCA and ROSC Who Were Treated Before and After the Introduction of the CB

ROSC cases (n = 15)

Before CB group^a (n = 6)

After CB group^a (n = 9)

^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; OHCA: out-of-hospital cardiac arrest; ROSC: return of spontaneous circulation; IQR: interquartile range; SD: standard deviation.

Amount of adrenaline used until ROSC (mg), mean (SD)

4.5 (4.3)

1.9 (1.1)

0.098

Time from arrival at hospital to ROSC (min), median (IQR)

11.5 (10.25 - 28.5)

11.0 (4.0 - 12.0)

0.287

Time from arrival at hospital to administration of adrenaline (min), median (IQR)

3.5 (3.0 - 4.0)

3.0 (1.0 - 5.0)

0.763

**Table 6.** Comparison of Patients With OHCA and Non-ROSC Who Were Treated Before and After the Introduction of the Code Blue System
Non-ROSC cases (n = 45)	Before CB group^a (n = 24)	After CB group^a (n = 21)	P
^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; OHCA: out-of-hospital cardiac arrest; ROSC: return of spontaneous circulation; IQR: interquartile range; SD: standard deviation.
Amount of adrenaline used until confirmation of death (mg), median (IQR)	5.3 (2.2)	4.8 (2.1)	0.382
Time from arrival at hospital to confirmation of death (min), median (IQR)	49.5 (31.0 - 62.5)	30.0 (20.0 - 49.0)	0.053
Time from arrival at hospital to administration of adrenaline (min), median (IQR)	4.0 (3.0 - 5.25)	4.0 (3.0 - 5.0)	0.694

Table 6. Comparison of Patients With OHCA and Non-ROSC Who Were Treated Before and After the Introduction of the Code Blue System

Non-ROSC cases (n = 45)

Before CB group^a (n = 24)

After CB group^a (n = 21)

^aPatients in the After CB group (n = 30) were admitted from March 23, 2023, to July 31, 2024, and patients in the Before CB group, from March 30, 2022, to March 22, 2023. CB: Code Blue system; OHCA: out-of-hospital cardiac arrest; ROSC: return of spontaneous circulation; IQR: interquartile range; SD: standard deviation.

Amount of adrenaline used until confirmation of death (mg), median (IQR)

5.3 (2.2)

4.8 (2.1)

0.382

Time from arrival at hospital to confirmation of death (min), median (IQR)

49.5 (31.0 - 62.5)

30.0 (20.0 - 49.0)

0.053

Time from arrival at hospital to administration of adrenaline (min), median (IQR)

4.0 (3.0 - 5.25)

4.0 (3.0 - 5.0)

0.694