Improved Survival With Extracorporeal Cardiopulmonary Resuscitation Despite Progressive Metabolic Derangement Associated With Prolonged Resuscitation.

BACKGROUND: The likelihood of neurologically favorable survival declines with prolonged resuscitation. However, the ability of extracorporeal cardiopulmonary resuscitation (ECPR) to modulate this decline is unknown. Our aim was to examine the effects of resuscitation duration on survival and metabolic profile in patients who undergo ECPR for refractory ventricular fibrillation/ventricular tachycardia out-of-hospital cardiac arrest. METHODS: We retrospectively evaluated survival in 160 consecutive adults with refractory ventricular fibrillation/ventricular tachycardia out-of-hospital cardiac arrest treated with the University of Minnesota (UMN) ECPR protocol (transport with ongoing cardiopulmonary resuscitation [CPR] to the cardiac catheterization laboratory for ECPR) compared with 654 adults who had received standard CPR in the amiodarone arm of the ALPS trial (Amiodarone, Lidocaine, or Placebo Study). We evaluated the metabolic changes and rate of survival in relation to duration of CPR in UMN-ECPR patients. RESULTS: Neurologically favorable survival was significantly higher in UMN-ECPR patients versus ALPS patients (33% versus 23%; P=0.01) overall. The mean duration of CPR was also significantly longer for UMN-ECPR patients versus ALPS patients (60 minutes versus 35 minutes; P<0.001). Analysis of the effect of CPR duration on neurologically favorable survival demonstrated significantly higher neurologically favorable survival for UMN-ECPR patients compared with ALPS patients at each CPR duration interval <60 minutes; however, longer CPR duration was associated with a progressive decline in neurologically favorable survival in both groups. All UMN-ECPR patients with 20 to 29 minutes of CPR (8 of 8) survived with neurologically favorable status compared with 24% (24 of 102) of ALPS patients with the same duration of CPR. There were no neurologically favorable survivors in the ALPS cohort with CPR ≥40 minutes, whereas neurologically favorable survival was 25% (9 of 36) for UMN-ECPR patients with 50 to 59 minutes of CPR and 19% with ≥60 minutes of CPR. Relative risk of mortality or poor neurological function was significantly reduced in UMN-ECPR patients with CPR duration ≥60 minutes. Significant metabolic changes included decline in pH, increased lactic acid and arterial partial pressure of carbon dioxide, and thickened left ventricular wall with prolonged professional CPR. CONCLUSIONS: ECPR was associated with improved neurologically favorable survival at all CPR durations <60 minutes despite severe progressive metabolic derangement. However, CPR duration remains a critical determinate of survival.

Natural language processing of prehospital emergency medical services trauma records allows for automated characterization of treatment appropriateness.

BACKGROUND: Incomplete prehospital trauma care is a significant contributor to preventable deaths. Current databases lack timelines easily constructible of clinical events. Temporal associations and procedural indications are critical to characterize treatment appropriateness. Natural language processing (NLP) methods present a novel approach to bridge this gap. We sought to evaluate the efficacy of a novel and automated NLP pipeline to determine treatment appropriateness from a sample of prehospital EMS motor vehicle crash records. METHODS: A total of 142 records were used to extract airway procedures, intraosseous/intravenous access, packed red blood cell transfusion, crystalloid bolus, chest compression system, tranexamic acid bolus, and needle decompression. Reports were processed using four clinical NLP systems and augmented via a word2phrase method leveraging a large integrated health system clinical note repository to identify terms semantically similar with treatment indications. Indications were matched with treatments and categorized as indicated, missed (indicated but not performed), or nonindicated. Automated results were then compared with manual review, and precision and recall were calculated for each treatment determination. RESULTS: Natural language processing identified 184 treatments. Automated timeline summarization was completed for all patients. Treatments were characterized as indicated in a subset of cases including the following: 69% (18 of 26 patients) for airway, 54.5% (6 of 11 patients) for intraosseous access, 11.1% (1 of 9 patients) for needle decompression, 55.6% (10 of 18 patients) for tranexamic acid, 60% (9 of 15 patients) for packed red blood cell, 12.9% (4 of 31 patients) for crystalloid bolus, and 60% (3 of 5 patients) for chest compression system. The most commonly nonindicated treatment was crystalloid bolus (22 of 142 patients). Overall, the automated NLP system performed with high precision and recall with over 70% of comparisons achieving precision and recall of greater than 80%. CONCLUSION: Natural language processing methodologies show promise for enabling automated extraction of procedural indication data and timeline summarization. Future directions should focus on optimizing and expanding these techniques to scale and facilitate broader trauma care performance monitoring. LEVEL OF EVIDENCE: Diagnostic tests or criteria, level III.

Coronary Artery Disease in Patients With Out-of-Hospital Refractory Ventricular Fibrillation Cardiac Arrest.

BACKGROUND: The prevalence of coronary artery disease (CAD) among patients with refractory out-of-hospital (OH) ventricular fibrillation (VF)/ventricular tachycardia (VT) cardiac arrest is unknown. OBJECTIVES: The goal of this study was to describe the prevalence and complexity of CAD and report survival to hospital discharge in patients experiencing refractory VF/VT cardiac arrest treated with a novel protocol of early transport to a cardiac catheterization laboratory (CCL) for extracorporeal life support (ECLS) and revascularization. METHODS: Between December 1, 2015, and December 1, 2016, consecutive adult patients with refractory OH VF/VT cardiac arrest requiring ongoing cardiopulmonary resuscitation were transported by emergency medical services to the CCL. ECLS, coronary angiography, and percutaneous coronary intervention were performed, as appropriate. Functionally favorable survival to hospital discharge (Cerebral Performance Category 1 or 2) was determined. Outcomes in a historical comparison group were also evaluated. RESULTS: Sixty-two (86%) of 72 transported patients met emergency medical services transport criteria. Fifty-five (89%) of the 62 patients met criteria for continuing resuscitation on CCL arrival; 5 had return of spontaneous circulation, 50 received ECLS, and all 55 received coronary angiography. Forty-six (84%) of 55 patients had significant CAD, 35 (64%) of 55 had acute thrombotic lesions, and 46 (84%) of 55 had percutaneous coronary intervention with 2.7 ± 2.0 stents deployed per patient. The mean SYNTAX score was 29.4 ± 13.9. Twenty-six (42%) of 62 patients were discharged alive with Cerebral Performance Category 1 or 2 versus 26 (15.3%) of 170 in the historical comparison group (odds ratio: 4.0; 95% confidence interval: 2.08 to 7.7; p < 0.0001). CONCLUSIONS: Complex but treatable CAD was prevalent in patients with refractory OH VF/VT cardiac arrest who also met criteria for continuing resuscitation in the CCL. A systems approach using ECLS and reperfusion seemed to improve functionally favorable survival.

Minnesota Resuscitation Consortium's Advanced Perfusion and Reperfusion Cardiac Life Support Strategy for Out-of-Hospital Refractory Ventricular Fibrillation.

BACKGROUND: In 2015, the Minnesota Resuscitation Consortium (MRC) implemented an advanced perfusion and reperfusion life support strategy designed to improve outcome for patients with out-of-hospital refractory ventricular fibrillation/ventricular tachycardia (VF/VT). We report the outcomes of the initial 3-month period of operations. METHODS AND RESULTS: Three emergency medical services systems serving the Minneapolis-St. Paul metro area participated in the protocol. Inclusion criteria included age 18 to 75 years, body habitus accommodating automated Lund University Cardiac Arrest System (LUCAS) cardiopulmonary resuscitation (CPR), and estimated transfer time from the scene to the cardiac catheterization laboratory of ≤30 minutes. Exclusion criteria included known terminal illness, Do Not Resuscitate/Do Not Intubate status, traumatic arrest, and significant bleeding. Refractory VF/VT arrest was defined as failure to achieve sustained return of spontaneous circulation after treatment with 3 direct current shocks and administration of 300 mg of intravenous/intraosseous amiodarone. Patients were transported to the University of Minnesota, where emergent advanced perfusion strategies (extracorporeal membrane oxygenation; ECMO), followed by coronary angiography and primary coronary intervention (PCI), were performed, when appropriate. Over the first 3 months of the protocol, 27 patients were transported with ongoing mechanical CPR. Of these, 18 patients met the inclusion and exclusion criteria. ECMO was placed in 83%. Seventy-eight percent of patients had significant coronary artery disease with a high degree of complexity and 67% received PCI. Seventy-eight percent of patients survived to hospital admission and 55% (10 of 18) survived to hospital discharge, with 50% (9 of 18) achieving good neurological function (cerebral performance categories 1 and 2). No significant ECMO-related complications were encountered. CONCLUSIONS: The MRC refractory VF/VT protocol is feasible and led to a high functionally favorable survival rate with few complications.