Clinical outcome of in-hospital cardiac arrest: An observational study in Indian setting

Introduction

The acute and unexpected event of In-hospital cardiac arrests (IHCAs) poise a great challenge to any medical practitioner. The outcomes in cases of IHCAs remains poor to such an extent that resuscitation might not be even warranted. Data from the western countries have reported the incidence of IHCA to be 0.78 to 4.60 per 1000 admissions and even the mortality stats are also staggering as deaths reported in such studies are high despite the high-quality cardiopulmonary resuscitation (CPR).1, 2, 3, 4, 5, 6, 7 Due to recent trend in healthcare technology, hospital discharge rate has improved and has been reported to be around 25% in USA and even upto 35% in UK.5, 8, 9 The only positive thing that has been reported over the past 20 years about the IHCA is the improvement in the long-term survival of these patients and even the good functional outcomes after one year stands at round 13% for IHCA survivors. 10

Survival of the patient with good neurologic outcomes, functional status post arrest and discharge rates depends on multiple variables in terms of affected populations, onset of resuscitation efforts, proximity of trained providers, quality of resuscitation efforts by EMS or other trained personnel. Post arrest care is the common factor irrespective of IHCA or Out-of-hospital cardiac arrest (OHCA) and happens only within hospital setting. The fundamental goal of post-arrest care is to identify and control factors that precipitated the arrest, improve the probability of favourable neurologic recovery and outcomes, and minimise the consequences of cardiac arrest-associated injury and tissue damage. Studies have shown that with proper co-ordination alongside high-quality and comprehensive post-resuscitation care, favourable neurologic outcome can be obtained in terms of survival-to-hospital discharge rate in IHCAs. 11

IHCA & OHCA has been studied extensively in various parts of the world. But all the studies were done for patient admitted in ICU. Particularly for ward patients, there lies a big void in literature and hence this research study was undertaken in order to study the clinical outcome of in-hospital cardiac arrest for the patients admitted in ward. The main objectives of the study are as follows:

Materials and Methods

Results

In our study, there were 75 male patients (63%) and 44 female patients (37%). Male to female ratio of occurrence of cardiac arrest was 1.8:1 with no significant (p>0.05) difference. The probable cause of arrest was cardiac in 46 (38.7%) patients while it was non-cardiac in 73 (61.3%) patients. Out of 46 patients with cardiac cause of arrest, 54.3% were recovered while 45.7% died. Similarly, in 73 patients with non-cardiac cause of arrest, 56.2% were recovered while 43.8% succumbed. In female patients 61.4% had non cardiac cause and 38.6% had cardiac cause of arrest. While within male patients 61.3% had cardiac cause while 38.7% had non cardiac cause of arrest. More than 50% of the patients who had a cardiac arrest belonged to 61 to 80 years of age. As well as 8.4% patients less than 40 years age group had also developed cardiac arrest. There was statistically no significant (p>0.05) difference of cause of cardiac arrest in between the sex of patients and different age groups. The initial rhythm on monitor was asystole for 106 (89.08%) patients, 6 (5.04%) patients each had pulseless electric activity and ventricular tachycardia and only 1 (0.84%) had ventricular fibrillation. Out of 119 patients, 66 (55.5%) patients had revival immediately post resuscitation and 53 (44.5%) patients died post resuscitation. There was statistically no significant (p>0.05) difference of the mortality outcome in the between cardiac and non-cardiac cause of arrest. Out of 119 patients, 7 patients had a shockable rhythm (pulseless VT or VF) and 6 patients out of them survived immediate post resuscitation and 5 patients survived at discharge. While 112 patients had non-shockable initial rhythm and only 60 patients out of them survived immediate post resuscitation; 29 patients survived 24 hours’ post-resuscitation and only 11 patients survived at discharge.

Discussion

The prospective observational hospital based study was carried out at Deenanath Mangeshkar hospital, Pune on 119 patients to ascertain the clinical outcome of in-hospital cardiac arrest. We also studied associated factors like age, sex, cause of arrest either cardiac or non-cardiac, any comorbidity, time since arrest, initial rhythm on monitor at the start of resuscitation & probable cause of arrest. Successful resuscitation was measured at 24 hours after the episode and at the time of discharge. The patient revived after resuscitation received therapeutic hypothermia. Out of 119 patients, 44 patients were female (37%) and 75 patients were male (63%) and male to female ratio of cardiac arrest patients was 1.8:1. 4.2% belonged to the age group <30 years, 4.2% patients belonged to the age group 31-40 years. 7.6 % patients had age 41-50 years. 11.8% patients were in the age group 51-60 years. 28.6% patients were in the age group 61-70 years of age. 25.2% patients were in the age group of 71-80 years. 18.5% patients were in the age group >80 years.

Cardiac arrest remains one of the most unexpected, dramatic, and life-threatening events in medicine. The most common electrical mechanism recorded previously for sudden cardiac arrest was ventricular fibrillation or pulseless sustained ventricular tachycardia. These were the initial rhythm recorded in 60-80% cardiac arrests, with ventricular fibrillation being the far more common of the two. Currently asystole has emerged as the most common mechanism recorded at initial contact (45-50% of cases) followed by pulseless electrical activity and ventricular fibrillation. Undoubtedly, a significant proportion of the asystole cases began as ventricular fibrillation and deteriorated to asystole because of long response times, but there are data suggesting an absolute reduction in ventricular fibrillation as well. Similar incidence reflects in our study too. We had 106 patients (89.08%) with an asystole as initial rhythm on monitor, 6 patients (5.04%) each for pulseless electric activity and ventricular tachycardia respectively & 1 patient (0.84%) had ventricular fibrillation.

Survival rate and neurological recovery of the patient vary widely, depending on whether an arrest was witnessed or unwitnessed and the initial cardiac rhythm during resuscitation. Patients found in a shockable rhythm have a much better prognosis if they are defibrillated early. In overall terms, the prognosis among patients found in a non-shockable rhythm is very poor. In our study, 7 patients had shockable rhythm & 112 patients had non-shockable rhythm. Immediately after resuscitation 6 (85.7%) out of 7 patients who had shockable rhythm survived and 60 (53.6%) out of 112 patients survive who had non-shockable rhythm reflecting (71.43%) patient with shockable initial rhythm had better outcome than patient with non-shockable rhythm (9.8%).

Even among patients with successful return of spontaneous circulation (ROSC) who are admitted to an intensive care unit, survival until hospital discharge has historically been less than 10% as suggested from a recent data pointing towards a steady improved survival of the patients. In our study, 5 (71.43%) out of 7 patients discharged had shockable rhythm and 11 (9.8%) out of 112 patients were discharged who had non-shockable rhythm.

Improvement in the survival rate and neurological outcomes of patients with cardiac arrest have focused on 2 principal areas of treatment. The first is increased education to improve immediate post- Cardiac arrest perfusion via national efforts promoting the 4 links in the chain of survival that include early access to emergency medical care, early cardiopulmonary resuscitation, early defibrillation, and early advanced cardiac life support. The second area is greater emphasis on post-resuscitation care, which includes optimising oxygenation and ventilation, avoiding hypotension (systolic blood pressure <90 mm Hg), treating immediate precipitants of Cardiac arrest such as acute coronary ischemia, and initiating Therapeutic Hypothermia (TH) when appropriate. The American Heart Association, the International Liaison Committee of Resuscitation, and the European Resuscitation Council recently published guidelines and recommendations covering the entire spectrum of post-resuscitation care. This review focuses on the practical aspects of implementing TH, one of the key therapeutic procedures in post-resuscitation care.

TTM which was previously called therapeutic hypothermia is the only intervention that has been shown to improve neurological outcomes after cardiac arrest. Induced hypothermia should occur soon after ROSC (return of spontaneous circulation). The decision point for the use of therapeutic hypothermia is whether or not the patient can follow commands (Lack of meaningful response to verbal commands). One of the most common methods used for inducing therapeutic hypothermia is a rapid infusion of ice-cold (4° C), isotonic, non-glucose-containing fluid to a volume of 30 ml/kg. The optimum temperature for therapeutic hypothermia is 32-36 ° C (89.6 to 96.8 °F). A single target temperature, within this range, should be selected, achieved, and maintained for at least 24 hours.

During induced TTM, the patient’s core temperature should be monitored with any one of the following: oesophageal thermometer, a bladder catheter in the non-anuric patients, or a pulmonary artery catheter if one is already in place. In our study, therapeutic hypothermia was achieved with cold saline and cold blankets. Total of 66 patients (55.5%) out of 119 received therapeutic hypothermia.

Of all the 119 patients who required cardiopulmonary resuscitation, 44 patients were ward admissions in first place. Out of these 44 patients, 25% (11 patients) survived 24 hours post resuscitation and a total of 9% (4 patients) were discharged from the hospital and sent home later. Rest 75 patients required ICU admission initially and were later sent to ward where they sustained a cardiac arrest. 24 patients (32%) from this group survived 24 hours post cardiopulmonary resuscitation and 12 patients (16%) were discharged from the hospital later. From above figures, it is evident that patients who had ICU admission initially had slightly higher incidence of survival at 24 hours post cardio pulmonary resuscitation compared to those who were admitted directly in the ward. Also the incidence of Hospital discharges was slightly better in the patients who required ICU admission initially and later sent to ward where they suffered a cardiac arrest and provided cardiopulmonary resuscitation. Our observations are also limited by the fact that we couldn't recognise exact time period between arrest of patient and activation of code blue. The study is based on a single centre, which limits the generalizability of the results. Many risk factors influencing the outcome have not been included in the analysis. Also, many opted for non-escalation of treatment in view of age and multiple comorbidity. Moreover, the quality of CPR and the treatment protocol were not measured against the standard guidelines.

Conclusion

Outcome of in-hospital cardiac arrest patient depends on effectiveness of cardiopulmonary resuscitation, Post ROSC (Return of spontaneous circulation) aggressive hypothermia and other post resuscitation care. Poor outcomes have been seen to be due to multiple co-morbidities and delayed recognition of cardiac arrest. Patient with shockable initial rhythm on monitor had better outcomes than non-shockable, so early defibrillation is advised in shockable rhythm all over world in every protocols. Of all the patients who had a cardiac arrest, those with cardiac causes and electrolytes disturbance as a preceding cause of arrest had a better outcome.

Conflict of Interest

There are no conflicts of interest in this article.

Source of Funding

None.