Predictors of ROSC in witnessed aeromedical cardiac arrests

Automated Versus Manual Cardiopulmonary Resuscitation in Flight: Are We Being Safe?

OBJECTIVE

The primary purpose of this study was to compare the percentage of return of spontaneous circulation of in-flight cardiac arrest (IFCA) patients on admission to the emergency department (ED) who received in-flight standard cardiopulmonary resuscitation (s-CPR) versus automated cardiopulmonary resuscitation (a-CPR).

SETTING

EMS helicopter (HEMS) service in Midwest USA.

METHODS

This was a prospective, consecutive case series of adult patients who had IFCA of any cause managed with a-CPR between October 1, 2012, and February 8, 2016 (40 months), at a helicopter emergency medical service (HEMS) in the Midwestern United States. The series was compared with a historical control of patients who had IFCA managed by s-CPR between June 1, 2009, and September 30, 2012 (40 months).

RESULTS

Ninety-five runs (39 s-CPR and 54 a-CPR) were included. There was no significant difference in survival between the 2 groups upon HEMS leaving the ED. Cardiopulmonary resuscitation was performed for a significantly longer period of time in the a-CPR cohort than in the s-CPR cohort, and a significantly higher percentage of patients were undergoing active compressions upon loading into the aircraft in the a-CPR cohort.

CONCLUSION

There was no difference in return of spontaneous circulation on ED admission between the 2 compression methodologies. In-flight use of a-CPR allows HEMS providers to be safe and compliant with Federal Aviation Administration regulations. It also meets the public and medical profession's expectations of the treatment of IFCA with high-quality cardiopulmonary resuscitation by HEMS.

Cardiac Arrest in Flight: A Retrospective Chart Review of 92 Patients Transported by a Critical Care Air Medical Service

OBJECTIVE

The purpose of this study was to describe the incidence, characteristics, and outcomes of cardiac arrest in the air medical environment so that we can begin to understand predictors of in-flight cardiac arrest and identify opportunities to improve care.

METHODS

This retrospective observational study was undertaken at Airlift Northwest from 2013 to 2017. Descriptive statistics of adult patients with medical and traumatic etiologies of cardiac arrest were analyzed and compared.

RESULTS

Of the 13,915 adult patients transported during the study period, fewer than 1% (N = 92) had a cardiac arrest during transport. Of those, 42% in the overall cohort had return of spontaneous circulation on arrival at the destination hospital. Medical etiologies of cardiac arrest were more common than traumatic (65% vs. 35%), more likely to have an initial shockable rhythm (30% vs. 3%, P = .004), and more frequently arrived at the receiving hospital with return of spontaneous circulation (57% vs. 31%, P = .03). Rearrest in transport occurred frequently (39%). Most patients were hypotensive before cardiac arrest, and peri-intubation cardiac arrest occurred in 12% of patients.

CONCLUSION

Cardiac arrest during air medical transport is a rare event that requires a high level of critical care to treat refractory cardiac arrests, hemodynamic instability, and airway compromise.

Addressing the Global Burden of Trauma in Major Surgery

Despite a technically perfect procedure, surgical stress can determine the success or failure of an operation. Surgical trauma is often referred to as the "neglected step-child" of global health in terms of patient numbers, mortality, morbidity, and costs. A staggering 234 million major surgeries are performed every year, and depending upon country and institution, up to 4% of patients will die before leaving hospital, up to 15% will have serious post-operative morbidity, and 5-15% will be readmitted within 30 days. These percentages equate to around 1000 deaths and 4000 major complications every hour, and it has been estimated that 50% may be preventable. New frontline drugs are urgently required to make major surgery safer for the patient and more predictable for the surgeon. We review the basic physiology of the stress response from neuroendocrine to genomic systems, and discuss the paucity of clinical data supporting the use of statins, beta-adrenergic blockers and calcium-channel blockers. Since cardiac-related complications are the most common, particularly in the elderly, a key strategy would be to improve ventricular-arterial coupling to safeguard the endothelium and maintain tissue oxygenation. Reduced O2 supply is associated with glycocalyx shedding, decreased endothelial barrier function, fluid leakage, inflammation, and coagulopathy. A healthy endothelium may prevent these "secondary hit" complications, including possibly immunosuppression. Thus, the four pillars of whole body resynchronization during surgical trauma, and targets for new therapies, are: (1) the CNS, (2) the heart, (3) arterial supply and venous return functions, and (4) the endothelium. This is termed the Central-Cardio-Vascular-Endothelium (CCVE) coupling hypothesis. Since similar sterile injury cascades exist in critical illness, accidental trauma, hemorrhage, cardiac arrest, infection and burns, new drugs that improve CCVE coupling may find wide utility in civilian and military medicine.

Hemodynamic rescue and ECG stability during chest compressions using adenosine and lidocaine after 8-minute asphyxial hypoxia in the rat

INTRODUCTION

Sudden cardiac death generally arises from either ventricular fibrillation or asphyxial hypoxia. In an effort to translate the cardioprotective effects of adenosine and lidocaine (AL) from hemorrhagic shock to cardiopulmonary resuscitation, we examined the effect of AL on hemodynamics and electrocardiogram (ECG) stability in the rat model of asphyxial hypoxia.

METHODS

Male Sprague-Dawley rats were randomly assigned to 1 of 4 groups (n = 8): saline (SAL), adenosine (ADO), lidocaine (LIDO), and AL. Cardiac arrest (mean arterial pressure <10 mm Hg) was induced by clamping the ventilator line for 8 minutes. A 0.5-mL intravenous drug bolus was injected followed by chest compressions (300 min(-1)), which were repeated every 5 minutes for 1 hour.

RESULTS

Return of spontaneous circulation was achieved in 5 SAL (62.6%), 4 ADO (50%), 7 LIDO (87.5%), and 8 AL rats (100%) within 5 minutes but could not be sustained. During chest compressions, mean arterial pressure was consistently higher in the AL-treated rats compared with all groups (P < .05; 35-45 and 55 minutes) followed by the LIDO group and was lowest in the ADO and SAL groups (P < .05). Systolic pressure followed a similar pattern. In addition, diastolic pressure in the AL-treated rats was significantly higher from 25 to 60 minutes than LIDO and ADO alone or SAL, and heart rate was 30% to 40% lower. Improved ECG rhythm and R-R variability were apparent in AL-treated rats during early compressions and hands-off intervals.

CONCLUSIONS

We conclude that a small bolus of 0.9% NaCl AL improved hemodynamics with possible diastolic rescue and ECG stabilization during chest compressions compared with ADO, LIDO, or SAL controls.

Adverse events during rotary-wing transport of mechanically ventilated patients: a retrospective cohort study

Introduction

Patients triaged to tertiary care centers frequently undergo rotary-wing transport and may be exposed to additional risk for adverse events. The incidence of physiologic adverse events and their predisposing factors in mechanically ventilated patients undergoing aeromedical transport are unknown.

Methods

We performed a retrospective review of flight records of all interfacility, rotary-wing transports to a tertiary care, university hospital during 2001 to 2003. All patients receiving mechanical ventilation via endotracheal tube or tracheostomy were included; trauma, scene flights, and fixed transports were excluded. Data were abstracted from patient flight and hospital records. Adverse events were classified as either major (death, arrest, pneumothorax, or seizure) or minor (physiologic decompensation, new arrhythmia, or requirement for new sedation/paralysis). Bivariate associations between hospital and flight characteristics and the presence of adverse events were examined.

Results

Six hundred eighty-two interfacility flights occurred during the period of review, with 191 patients receiving mechanical ventilation. Fifty-eight different hospitals transferred patients, with diagnoses that were primarily cardiopulmonary (45%) and neurologic (37%). Median flight distance and time were 42 (31 to 83) km and 13 (8 to 22) minutes, respectively. No major adverse events occurred during flight. Forty patients (22%) experienced a minor physiologic adverse event. Vasopressor requirement prior to flight and flight distance were associated with the presence of adverse events in-flight (P < 0.05). Patient demographics, time of day, season, transferring hospital characteristics, and ventilator settings before and during flight were not associated with adverse events.

Conclusion

Major adverse events are rare during interfacility, rotary-wing transfer of critically ill, mechanically ventilated patients. Patients transferred over a longer distance or transferred on vasopressors may be at greater risk for minor adverse events during flight.