You are dispatched to a rural ED interfacility transfer to cath lab for a 54 y/o male STEMI. His presenting complaint was sudden onset chest pain that radiates to his back, dyspnea, and diaphoresis. His arrival ECG (below) showed a STEMI. He was given aspirin and a heparin drip was started. No other interventions were performed.
Vitals: HR: 110 BP: 101/70 RR: 22 SpO2: 100% NRB
General: male, diaphoretic, uncomfortable
CV: tachycardia, no m/r/g
Pulm: clear bilaterally
Abdomen: soft, non-tender, non-distended
MSK: moves all four extremities
Neuro: awake, alert, oriented x 4
Past Medical History: Hypertension (on beta blocker, ACE-I), Hyperlipidemia (on statin), Diabetes (on metformin)
What are your major actions prior to flight?
A variety of wise action steps were suggested prior to flight: getting report from referring providers, brief history and physical, applying our monitor, weaning oxygen as tolerated from the non-rebreather to avoid hyperoxia, ensuring adequate IV access. One essential step prior to a STEMI flight is to apply defib pads to the patient’s chest preemptively should he develop a dysrhythmia during flight — this avoids the logistical hassle of frantically trying to apply anterior-posterior pads mid-flight and intra-arrest. Several R1s were a bit concerned about the patient’s story of sudden onset pain and radiation to back; knowing that a small number of aortic dissections can manifest with STEMI due to dissection into the coronary arteries, they astutely asked for a chest x-ray prior to flight, which was normal. While CXR’s are not entirely sensitive for dissection, a normal CXR was reassuring and — absent other objective signs of dissection such as asymmetric pulses or hypotension — their pretest probability for dissection was not so high that they wanted to delay transfer by pursuing additional diagnostic modalities. For the sake of time, we usually do not continue heparin drips in-flight on STEMI patients, so this was discontinued. Additional logistical steps included confirming the helicopter loading plan (“hot load” where the helicopter is running vs. “cold load” where the engine is off)…however a minor obstacle arose before the patient could be loaded…
Soon after applying the defibrillator pads prior to flight, the patient was noted to be having a “seizure” by staff. What now?
As thoughtfully paranoid Flight Physicians, this “seizure” was soon recognized as pulselessness with associated cerebral anoxic convulsions —the patient was in ventricular fibrillation on the monitor. At this point, the initial consensus was to quickly start CPR and defibrillate that rhythm. Early role designation was also recognized as paramount — a linchpin to any successful and elegant resuscitation. In terms of airway, most elected to place a supraglottic airway amidst a hectic code as opposed to endotracheal intubation. Standard ACLS was initiated with amiodarone 300 mg and epinephrine 1mg. The next essential question posed was whether or not we want to thrombolyse this patient who, while destined for PCI, had now arrested in the context of a known STEMI. While we do not currently carry thrombolytics on Air Care, we certainly can acquire them from the outside hospital, so docs asked for either alteplase or tenecteplase from the transferring hospital pharmacy. The point was raised that tenecteplase has the benefit of higher fibrin affinity and is only a bolus without necessitating a drip. Ultimately, if the patient remained in arrest, most physicians would perform thrombolysis with whichever agent was most readily available at the outside hospital. An approximate dose of 0.9 mg/kg of either drug should be sufficient as an intra-arrest bolus.
Should the patient remain in a ventricular fibrillation arrest, what other therapies beyond standard ACLS can we offer this patient?
Residents were quick to mention several less conventional but promising options for refractory VF, most notably double sequential defibrillation (DSD) and esmolol. DSD, the act of applying two sets of defibrillator pads and two simultaneous defibrillation, has several case reports showing improved defibrillation success — this is probably less due to increased energy as it is improved defibrillation vectors making a successful “hit” more likely. However, this is still controversial as these devices were not designed for this purpose and therefore may be damaged with this practice. A 500 mcg/kg bolus of esmolol works theoretically by blunting the Beta-1 chronotropy associated with a tachydysrhythmia and has shown promise in case series as well. With thrombolysis and these additional measures for refractory VF, ROSC is finally obtained…
What post-ROSC interventions would you like to perform before flight?
The traditional reflex post-ROSC of any patient is to obtain a 12-lead ECG, which makes sense but some raised the question of whether it would change our management in this case because we already know this patient has a STEMI. Similarly, some providers might change out the supraglottic airway for an endotracheal tube prior to flight while others would leave it in as long as there was good end tidal capnography. On the other hand, there was resounding consensus for obtaining an accurate blood pressure post-ROSC and initiating targeted temperature management should the patient not respond to command after the arrest. In the critical care transport environment, this is most easily accomplished using cold packs and cool fluids if available. Another important suggestion post-ROSC was to initiate drips of medications that worked during the arrest and/or are necessary to support the patient’s hemodynamics, most notably amiodarone and epinephrine. Finally, some physicians brought up the importance of maintaining post-cardiac arrest homeostasis, i.e., normoxia, normocarbia, normotension, etc.
Despite your best efforts, the patient goes back into a VF arrest during transport (in flight). How do you want to coordinate the logistics of this arrest in the aircraft with just you and a flight nurse?
This is a challenging scenario for even experienced flight teams — a cardiac arrest in close quarters, with often only two providers, and sometimes amidst turbulence or during critical phases of flight. In addition to simply cursing their luck, the R1s made great suggestions regarding the micro-logistics of crew resource management in this situation: who initiates compressions, who draws up drugs, who runs the monitor. They also brought up the importance of excellent intra-crew communication, including making it clear who is going to do what and keeping the pilot up to speed. Communication was also important with the receiving facility to prepare them for the change in patient status.
In sum, this case really challenged rising Flight Docs with the many issues that can arise from even a seemingly simple STEMI transfer. Some great points were raised to ensure our patients get excellent care, from simply verifying appropriate STEMI diagnosis to intra-arrest thrombolytics and aggressive management of refractory ventricular fibrillation. Stay tuned for next month’s case and discussion points!