Introduction. In-hospital cardiac arrest (IHCA) is a common event in hospitals representing an urgent situation with the necessity of fast medical expertise. IHCA is still associated with high mortality and severe long-term morbidity among hospitalized patients. In this study, we aimed to investigate 1) patient characteristics; 2) independent predictors associated with 30-day in-hospital mortality; and 3) 30-day in-hospital mortality in patients with IHCA. 

Methods. We analyzed all patients (>18 years) with IHCA at the University Heart and Vascular Center Hamburg between Janurary 2014 and April 2017, using data from the Resuscitation Registry. Univariable and multivariable Cox regression models were fitted to assess predictors of outcomes in patients with IHCA.

Results. In total, 368 patients with IHCA were analyzed. The median age was 73 years and 33.4% (n=123) were female. The most common cardiovascular comorbidities were hypertension (76.4%, n=278), smoking (33.5%, n=122), and diabetes (29.4%, n=107). A shockable rhythm was found in 20.9% of patients (ventricular fibrillation 13.3% (n=49); ventricular tachycardia 7.9% (n=29). A non-shockable rhythm was found in 169 patients (45.9%) including 29.1% (n=107) with asystole and 16.8% (n=62) with pulseless electrical acitivity (PEA) as initial rhythm. Complete AV block was found in 7 patients (1.9%). Additionally, 28.5% (n=105) of patients with IHCA had an undefined initial rhythm. A total number of 173 (47%) patients survived beyond 30 days, whereas 91 (n=52.6%) of these were discharged for rehabilitation. Independent predictors associated with higher likelihood for 30-day in-hospital mortality are shown in Figure 1. After adjustment for various confounders, factors associated with a significantly higher likelihood of 30-day in-hospital mortality were advanced age (hazard ratio (HR) 1.03, 95% confidence interval (CI) 1.01-1.05), need for use of epinephrine (HR 4.64, 95% CI 1.96-10.94), systolic blood pressure <90mmHg (HR 1.72, 95% CI 1.09-2.71), and lactate levels >2mmol/l (HR 6.50, 95% CI 2.32-18.23), and the need for dialysis (HR 2.74, 95% CI 1.80-4.18), and higher potassium levels at (HR 1.32,  95% CI 1.08-1.60). Achievement of return of spontaneous circulation (ROSC) without mechanical circulatory support (MCS) (HR 0.33, 95% CI 0.19-0.58), need for invasive coronary angiography and/or percutaneous intervention (HR 0.53, 95% CI 0.33-0.87), and the duration of antibiotic therapy (HR 0.87, 95% CI 0.83-0.91) were associated with a significantly lower risk of 30-day in-hospital mortality. The overall 30-day in-hospital mortality in patients with IHCA was 46.7% (n=172).

Conclusion. In this contemporary study, patients with IHCA face a high 30-day in-hospital mortality of about ~47%. The majority of patients with IHCA (~45%) had a non-shockable initial rhythm and one out of five patients had a shockable initial rhythm (~20%). Multiple factors were associated with an increased risk of 30-day in-hospital mortality including advanced age, need for use of epinephrine, and lactate levels >2mmol/l, whereas the achievement of ROSC without MCS and the need for invasive coronary angiography and/or percutaneous intervention as possible surrogate marker for acute myocardial infarction were associated with a lower risk of 30-day in-hospital mortality. As prognosis following IHCA is poor, further studies are warranted to gain new insights into beneficial approaches for the management in patients with IHCA.