In-hospital cardiac arrest: impact of monitoring and witnessed event on patient survival and neurologic status at hospital discharge.

CONTEXT: In-hospital cardiac arrest is a significant public health problem with a low probability of patient survival to hospital discharge.

OBJECTIVE: We evaluated the survival rates for adults with in-hospital cardiac arrest based on whether the arrest was witnessed and/or monitored. Our hypothesis is that patients with either a witnessed or monitored arrest had improved survival to hospital discharge with intact neurologic function.

DESIGN, SETTING, AND PATIENTS: We studied a cohort study of 74,213 patients who suffered in-hospital cardiac arrest from January 1, 2000 through February 1, 2008 at the 369 hospitals participating in the National Registry of Cardiopulmonary Resuscitation.

INTERVENTIONS: The primary exposure of interest was whether the arrest was witnessed and/or monitored (i.e. electrocardiography, pulse oximetry, apnea, or bradycardia monitoring) at the time of arrest. Events were classified as being both monitored and witnessed, monitored only, witnessed only, or neither witnessed nor monitored.

MAIN OUTCOME MEASURES: Survival to hospital discharge and cerebral performance category at time of discharge.

RESULTS: A total of 73% of patients suffering in-hospital cardiac arrest were witnessed and monitored; 10% were monitored but not witnessed; 9% were witnessed but not monitored; and 8% were neither witnessed nor monitored. Compared with those who were unmonitored/unwitnessed, each of the three groups of patients who were monitored and/or witnessed were over twice as likely to survive to hospital discharge with a cerebral performance category of 1 or 2 (monitored/witnessed OR=2.40, 95% CI: 2.08, 2.76; monitored-only OR=2.12, 95% CI: 1.81, 2.47; witnessed-only OR=2.43, 95% CI: 2.10, 2.83).

CONCLUSIONS: Patients who are witnessed and/or monitored at the time of cardiac arrest demonstrate a significantly higher rate of survival to hospital discharge compared to those patients who are neither monitored nor witnessed. Monitored and/or witnessed cardiac arrest patients were also more likely to be discharged with favorable neurologic outcome. Cardiac monitoring confers no additional outcome benefit over direct observation of patients suffering in-hospital cardiac arrest.