An optimal transition time to extracorporeal cardiopulmonary resuscitation for predicting good neurological outcome in patients with out-of-hospital cardiac arrest: a propensity-matched study

Abstract

Introduction: Prolonged conventional cardiopulmonary resuscitation (CCPR) is associated with a poor prognosis in out-of-hospital cardiac arrest (OHCA) patients. Alternative methods can be needed to improve the outcome in patients with prolonged CCPR and extracorporeal cardiopulmonary resuscitation (ECPR) can be considered as an alternative method. The objectives of this study were to estimate the optimal duration of CPR to consider ECPR as an alternative resuscitation method in patients with CCPR, and to find the indications for predicting good neurologic outcome in OHCA patients who received ECPR.

Methods: This study is a retrospective analysis based on a prospective cohort. We included patients ≥ 18 years of age without suspected or confirmed trauma and who experienced an OHCA from May 2006 to December 2013. First, we determined the appropriate cut-off duration for CPR based on the discrimination of good and poor neurological outcomes in the patients who received only CCPR, and then we compared the outcome between the CCPR group and ECPR group by using propensity score matching. Second, we compared CPR related data according to the neurologic outcome in matched ECPR group.

Results: Of 499 patients suitable for inclusion, 444 and 55 patients were enrolled in the CCPR and ECPR group, respectively. The predicted duration for a favorable neurologic outcome (CPC1, 2) is < 21 minutes of CPR in only CCPR patients. The matched ECPR group with ≥ 21 minutes of CPR duration had a more favorable neurological outcome than the matched CCPR group at 3 months post-arrest. In matched ECPR group, younger age, witnessed arrest without initial asystole rhythm, early achievement of mean arterial pressure ≥ 60 mmHg, low rate of ECPR-related complications, and therapeutic hypothermia were significant factors for expecting good neurologic outcome.

Conclusions: ECPR should be considered as an alternative method for attaining good neurological outcomes in OHCA patients who required prolonged CPR, especially of ≥ 21 minutes. Younger or witnessed arrest patients without initial asystole were good candidates for ECPR. After implantation of ECPR, early hemodynamic stabilization, prevention of ECPR-related complications, and application of therapeutic hypothermia may improve the neurological outcome.

Figure 1

Selection of study patients and study design. KUED, Korea university emergency department; OHCA, out-of-hospital cardiac arrest; DNAR, do not attempt resuscitation; CPR, cardiopulmonary resuscitation; ECPR, extracorporeal CPR group; CCPR, conventional CPR group; mECPR, matched ECPR group; mCCPR, matched CCPR group; CPC, cerebral performance category.

Figure 2

Trends of outcomes in the conventional cardiopulmonary resuscitation (CCPR) and extracorporeal cardiopulmonary resuscitation (ECPR) groups according to the cardiopulmonary resuscitation (CPR) duration. In the ECPR group, the longest CPR duration with a good neurologic outcome was 120 minutes. CPC, cerebral performance category.

Figure 3

Receiver-operating characteristic (ROC) curves for the cutoff time of cardiopulmonary resuscitation (CPR) duration for predicting a good neurological outcome in the conventional cardiopulmonary resuscitation (CCPR) group ( P <0.001). The cutoff value was 21 minutes. AUC, area under the curve.

Figure 4

Kaplan-Meier plot of survival with a good neurological outcome at 3 months post cardiac arrest for patients who experienced out-of-hospital cardiac arrest (OHCA) with cardiopulmonary resuscitation (CPR) duration ≥21 minutes. The extracorporeal CPR (ECPR) group showed better neurological outcomes compared to the conventional CPR (CCPR) group at 3 monthS post arrest.

Figure 5

Dot-plot of standardized mean differences before and after matching in study patients with a cardiopulmonary resuscitation (CPR) duration ≥21 minutes. ROSC = return of spontaneous circulation.

Figure 6

Outcomes of the matched extracorporeal cardiopulmonary resuscitation (mECPR) and matched conventional cardiopulmonary resuscitation (mCCPR) groups after propensity-score-matching in patients with cardiopulmonary resuscitation (CPR) duration ≥21 minutes. CPC, cerebral performance category.

Figure 7

Comparison of the rate of good neurologic outcomes in the matched extracorporeal cardiopulmonary resuscitation (mECPR) and matched conventional cardiopulmonary resuscitation (mCCPR) groups according to the cardiopulmonary resuscitation (CPR) duration. CPR duration between 21 to 80 minutes showed that mECPR had a significantly greater rate of good neurologic outcomes (CPC 1, 2). CPC, cerebral performance category.