A quick response in an emergency situation is the key to saving lives; in this regard, code blue is one of the most important codes in hospitals for resuscitation.

Code Blue is a common emergency code used in cases of cardiac arrest in hospitals to alert trained emergency response teams. ¹ The use of codes is mainly to convey essential information quickly to staff while preventing misunderstandings and panic among hospital visitors. For the effective functioning of the code blue system, when a code blue situation arises, personnel must identify the situation and call the experts immediately. ²

According to standard resuscitation guidelines, the response to a code blue call consists of emergency response team activation, cardiopulmonary resuscitation (CPR), and defibrillation. The goal of CPR is to restore and maintain perfusion to the vital organs until the underlying cause of the arrest is detected and as much as possible, is reversed. However, even with the best efforts, survival rates of patients who suffer sudden cardiac arrest remains low even in the best tertiary care hospitals. Survival of the patient mainly depends on a multitude of factors related to the demography of the patient and cause of the arrest. The initial rhythm following an arrest is an important predictor of survival. Shockable rhythm seems to offer better prognosis compared to non-shockable rhythm, cardiac origin used to have a more favorable outcome compared to non-cardiac causes, and the response time following arrest and the quality of CPR also play an important role. If performed in an appropriate manner return of spontaneous circulation (ROSC) is achieved. Therefore, it is very important to study the pre-arrest parameters and obtain a good understanding of the outcome predictors for code blue cases. ³

Desai et al. conducted a retrospective pilot study in a secondary care private hospital in Maharashtra (2022) and investigated 63 code blue events, over a period of four months. Among the 63 code blue events 87.3% were initiated in critical care units. This study also showed a male predominance (71.4%). The maximum blue code was initiated for patients with cardiac conditions. Shockable rhythm was noted in 8 patients. Twelve patients survived and 40 died within 24 h. ⁴

A retrospective study was conducted by Hazra et al. in Christian Medical College, Tamil Nadu India (2021), on code blue declared in the Emergency Department between January 2018 and June 2019. The study included 435 patients above the age of 15 years and showed a male predominance with a mean age of 54.5 years. Most common presumed cause was of an underlying cardiac illness (42.2%). Pulseless electrical activity (85.5%) was the more common than asystole among the non-shockable rhythms. ROSC was attained in 184(44.1%) of the patients, of whom 56 (13.4%) were discharged alive from the hospital. ³

A cross-sectional study was conducted by Mitra et al. in a multispecialty teaching hospital in Bihar from April 2018 to March 2019. During this period, 111 code blue calls were declared. This study also showed a male (72.1%) predominance. The mean age of the code blue calls was 64.06 years. Among the departments with maximum code blue calls, this study showed oncology department with maximum cases(37.84%). In the time distribution, the majority of cases occurred between 8pm and 12 am. The initial rhythm was asystole followed by pulseless electrical activity. ¹

This was a retrospective observational descriptive study by Patil et al. in Bharti Hospital and Research Center from September 2011 to December 2012. This study included 260 code blue calls that were initiated during this period. It showed that casualty to be the most common place where code blue calls were initiated. The most common age group was found out to be the 21-30 age group followed by 51-60 age group. Indication for code blue initiation was cardiopulmonary arrest (88 patients, 33.84%). Immediate survival was observed in 31 patients (35.2%); among them, 9 patients were discharged with favorable outcomes. ²

A retrospective cohort study conducted by Simsek et al. in Sanko University, Department of Anesthesiology and Reanimation, Turkey investigated 419 code blue incidents. Among the 419 code blue calls, 339 were true code blues. In total, 207 patients were resuscitated. A total of 138 code blues were initiated in the emergency room. The code blue calls initiated showed a male predominance. ⁵

A retrospective study conducted by Ulludag et al. in the Adiyaman Training and Research Hospital in Turkey investigated 188 code blue incidents from January 2018 to December 2018. The mean patient age was 73.4. This study also showed male predominance (55%). Palliative care medicine unit was the unit which had maximum code blue incidents (21.8%). Initial rhythm was found out to be ventricular tachycardia/ventricular fibrillation (49%). Among the initiated code blue incidents, 21.08% (n-31) were able to be resuscitated. ⁶

A Study conducted by Monangi et al. in Army Hospital (Research and Referral Hospital), New Delhi, India, investigated 694 calls, of which 620 calls were true code blue calls. The mean age of patients was 56.06 years and survival in patients aged <60 years was found to be higher than patients aged >60 years. The most common rhythm noted was Asystole (371). ⁷

The study was conducted at the KMC hospital Ambedkar circle Mangalore in the state of Karnataka, India. This was a hospital-based, retrospective, record-based study. The study included Cases of Code Blue in KMC Hospital Mangalore from January 2022 to December 2022, and the study duration was from the date of approval by the institutional ethical committee till February 1, 2023. The study sample included all code blue calls activated in the above-mentioned time frame.

The data extraction sheet was prepared based on information available in the records, and institutional ethical committee clearance was taken prior to commencement of the study. The investigator visited the medical records department to collect the data. The collected information was filled into a structured form.

The proforma consisted of study variables, including the demographic and clinical profiles of patients. Records of all code blue cases were reviewed, and information pertaining to the study was entered into the proforma. The collected information was kept confidential.

The data was analyzed. Descriptive and inferential statistical analysis were carried out in the present study. Results on continuous measurements were presented on Mean ± SD (standard deviation) and results on categorical measurements were presented in Number (%). Significance is assessed at 5 % level of significance. The results are presented in percentages tables, bar-charts, and graphs. Associations were calculated using the chi-square test. Statistical significance was set at p<0.05.

In our study it was found that the age group 60-80 had the maximum percentage of code blue cases at 58.1% ( Table 1) In Gender distribution code blue cases were more announced for males in the study at 55.8% than females at 44.2% ( Table 2). For the activation of code blue cases, it was found that patient being unconscious was the most common cause at 83%. Most common place where code blue was announced was found to be the ward at 66%, compared to other places.

In most of the announced code blue cases, pulse was absent in initial check (74.4%). In 59.7% announced code blue cases it was identified that CPR was initiated by the staff on scene before the arrival of the code blue team ( Table 3). It was also found that code blue response time was within 1-2 mins in 50% of cases and 3-6 mins in 46.5% of cases. Asystole was the most common initial rhythm which was detected in the study at 66.3%, followed by a perfusing rhythm at 20.9% ( Table 4). Myocardial infarction was the initial cause of the arrest. In most of the code blue cases, it was non-shockable rhythm (82.4%) as compared to shockable rhythm.

ROSC was attained in 45.2% of cases and in 54.8% of the cases it was not attained. It was found that early code blue response resulted in favorable outcomes where the survival was higher (53.3%) if the response time was less than 2 min ( Table 6).

Factors such as age and initial rhythm significantly affected the code blue success rate.

Our study is consistent with other studies that reported that the survival rate declined significantly with increasing age.

Asystole was the predominant rhythm at the time of CPR initiation, which was consistent with other studies, which also highlighted that initial rhythm had a significant effect on outcome.

Early initiation of CPR was also found to have a better outcome than delayed CPR initiation. These statistics also highlight the importance of early initiation of CPR by a bystander with favorable outcomes.

In conclusion, CPR performed by a trained code blue team in a hospital can help achieve better results. The initiation of bystander CPR has been proven to have favorable outcomes. Better training of staff can result in better outcomes. Staff training can also help in reduce false-code blue calls.

Therefore, it is vital to have Basic Life Support (BLS) training for all staff to obtain better outcomes in code blue cases.

This study was approved by institutional ethics committee Kasturba Medical College Mangalore (Protocol number IECKMCMLR-11/2022/460). Initial approval was received on 16/11/2022.

Approval from medical superintendent of the hospital was taken to access the data from the medical records department.

Since the study was a retrospective record-based study with data collected from medical records, taking patient consent was waived off from ethical committee.