Does Time Matter in In-Hospital Cardiac Arrest (IHCA)?

Guidelines for termination of IHCA are generally very vague. It is typically a subjective decision by a physician to terminate efforts. Recently, a very large study was published in the Lancet in October 2012 evaluating this very topic.

• Retrospective Analysis
• Reviewed Get With the Guidelines-Resuscitation (GWTG-R) National Registry (The largest in-hospital cardiac arrest registry)
• 64,339 patients with in-hospital cardiac arrest
• 435 hospitals
• Does increased duration of resuscitation improve survival rates
• Broke time into median quartiles of resuscitation: 16 minutes, 19 minutes, 22 minutes, and 25 minutes

• Immediate survival with ROSC during the cardiac arrest
• Survival to hospital discharge

• Median age was 69 years
• Male sex approximately 57%
• Initial cardiac arrest rhythm was VT/VF in 12,924 patients (20.1%)
• Initial cardiac arrest rhythm was PEA/Asystole in 51,415 patients (79.9%)
• Overall median duration of resuscitation was 17 minutes
• 31,198 patients (48.5%) achieved ROSC (44.8% in 10 minutes; 87.6% in 30 minutes)
• 9,912 patients (15.4%) survived to hospital discharge
• Median resuscitation time in patients achieving ROSC was 12 minutes
• Median resuscitation time in non-survivors was 20 minutes

• Longer resuscitation time increased overall survival

• Overall, there is a 12% higher likelihood of achieving ROSC and survival to discharge in 25 minute quartile group vs 16 minute quartile group
• In the PEA/Asystole group, there is a 15% higher likelihood of achieving ROSC and 20% higher likelihood of survival to discharge in the 25 minute quartile group vs 16 minute quartile group
• In the VT/VF group, there is a 6% higher likelihood of achieving ROSC, but no difference in survival to discharge in the 25 minute quartile group vs 16 minute quartile group

• There was no statistical difference in favorable neurological status (Cerebral Performance Category ≤2) between 25-minute quartile group vs 16-minute quartile group (82.0% vs 81.6% with P value of 0.858)

• The GWTG-R Registry is a voluntary registry therefore only larger hospitals may be represented
• This is an observational, retrospective study
• Relative risk values were used instead of absolute risk values
• Confounding factors (i.e. Quality of CPR, interventional cardiology, therapeutic hypothermia) are not accounted for in this study
• The study did not account for long term outcomes in survivors (i.e functional status and mortality)

• Patients at hospitals with longer resuscitation times had higher rates of ROSC and survival to discharge, especially with patients in PEA/Asystole.

• This particular study although, well powered, used relative risk values, but when looking at the absolute risk values, increasing the duration of CPR was marginal at best.
• Although not statistically significant in this study, it is a well known fact that longer resuscitation duration is associated with worsened neurological status at discharge
• The optimal resuscitation time is yet to be decided, but consider increasing duration of resuscitation to improve survival in patients with reversible causes of cardiac arrest.

Dr. Salim R. Rezaie is a physician at the University of Texas Health Science Center at San Antonio. He is double board-certified in Emergency Medicine and Internal Medicine.