Man v Machine

A few volunteer medic units around Baltimore County have purchased mechanical chest compression devices.  There are two types of mechanical devices available: load-distributing band CPR devices (LDB-CPR) and piston-driven CPR devices (PD-CPR).

Example of LDB-CPR device: AutoPulse (Zoll Medical Corporation)

Example of PD-CPR device: LUCAS (Physio-Control Inc.)   

Manual CPR - the old fashion way - using you hands - is denoted by the abbreviation M-CPR.

Station 500 Chestnut Ridge Volunteer Fire Company has had a LUCAS device in-service aboard Medic 505 for over a year (pictured below).  If Engine 501 first responds to a potential or actual cardiac arrest for a career medic unit - the engine crew grabs the LUCAS device as they roll out the door.  The device rapidly and easily clips onto a small board placed behind the patient's back, has velcro straps to secure the patient's hands, and can be easily loaded with the patient onto a backboard or Reeves stretcher.  Mechanical compressions can be started and stopped with the push of a button.  The device is light-weight and battery powered.  The rechargeable lithium-ion battery can run about 45 minutes.  A spare battery is usually packaged with the device.  When not in use, the LUCAS charges on a shelf in the medic unit.  Specs for this device can be found on Physio Control's website.

Mechanical CPR (LDB-CPR and PD-CPR) devices provide the following benefits:

• More effective and consistent CPR (consistent rate, depth, position)
• Machines do not fatigue
• More consistent compression recoil (upstroke phase of chest compression cycle)
• Defibrillation can be performed without stopping mechanical chest compressions
• Reduce risk of injury to EMS providers during transport to the hospital (i.e. no standing in the back of the medic unit responding priority 1 to the hospital)

High quality CPR is the catch phrase of the year in EMS systems around the US and something that our EMS leadership in Baltimore County is keenly interested in seeing become the standard of care.  

The fundamental concept of high quality CPR is uninterrupted, proper rate and depth compressions with little to no pause immediately before and after shocks and around pulse/rhythm checks.  Other skills during the course of resuscitation like intubation and IV insertion should ideally be performed without any interruption in the delivery of compressions.

This month in the journal Critical Care Medicine, Westfall et al published a study entitled, "Mechanical Versus Manual Chest Compressions in Out-of-Hospital Cardiac Arrest: A Meta-Analysis".  The study looked at the likelihood of obtaining return of spontaneous circulation (ROSC) in patients treated with manual compressions compared to those treated with mechanical CPR.  A total of 12 studies comprising of 6,538 subjects with 1,824 ROSC events were included in the analysis.

It is important to note that ALL of the four authors of this study either work for, consult for, or have received grants from Zoll (manufacturer of the AutoPulse).

When manual (M-CPR) compressions were compared with BOTH types of mechanical devices (LDB-CPR + PD-CPR devices) there was a significantly increased odds of ROSC when using mechanical CPR devices.  The odds of ROSC were significantly better (in this meta analysis) with LDB-CPR type devices (like the AutoPulse) as compared to the PD-CPR type mechanical devices (like the LUCAS).

There is NO analysis of neurologic outcomes in this study.  Furthermore, the authors conclude that these findings need to be validated in larger randomized controlled clinical trials.

The bottom line - mechanical devices cost money.  The money trees remain elusive.  It would be nice to see these devices on all eight of our DO vehicles.  In this man v machine meta analysis - machine wins.

But we humans can strive to be high quality CPR machines!

We need to focus our efforts on learning and rapidly implementing high quality manual CPR.  Members of Baltimore County's EMS Division recently attended a Resuscitation Academy at the Howard County Fire Rescue Academy jointly sponsored by Seattle Medic One.  This two day conference focused on every aspect of high quality CPR from dispatch directed CPR, to the actual performance of the resuscitation by EMS providers, to data collection, and even touched on caring for the patient's family during and after the arrest.  

Please look for more information on how Baltimore County Fire Department is implementing these high quality CPR initiatives in the next few weeks and months.

  

Win big on the strip

Time sensitive metrics are receiving increasing attention and scrutiny in Baltimore County and EMS jurisdictions throughout the country.  It is expected that we will detect STEMIs immediately, transmit a 12-lead ECG to the hospital within minutes of arrival at the patient's side, and deliver the patient to a cardiac intervention center priority 1 all while getting an IV established and completing a host of other tasks while going down bumpy roads backwards at high rates of speed.  Then there is the 'Golden Hour' of trauma care, the 3.5 hour 'window' for tPA in ischemic stroke, time to first shock for VF/VT arrests, and the list goes on.  There is so much to do and so little time to do it.  But we do.  And we love it.

In the rush to perform all of these tasks and utilize all of the technology floating out of the hospitals into our medic units (12-lead ECGs, video laryngoscopes, EZ IO drills, capnography, etc), we have to remember what is at the center of all of this excitement . . . .  the PATIENT.  

As many of you know, I have an enormously bushy squirrel tail.  I was driving home one night up 83N after a long shift in the ICU.  EMS 1, Engine 17, IV 395, and Medic 475 were dispatched for a medical box aboard an MTA bus in the Timonium area as I approached the Timonium Road exist on 83N.  Unable to resist the urge, I switched to central and called enroute.  EMS 1 beat me to the scene and was already in the bus assessing the patient when I arrived.  What I witnessed next was something I see less and less of these days.  EMS 1 was kneeling over the patient in the center isle of the bus, talking to the patient, and examining the patient.  He was NOT immediately hooking the patient up to the cardiac monitor, placing an Spo2 probe on his finger, or peeling back a shirt sleeve to look for an IV.  He was actually examining the patient - looking, listening, palpating - human contact.

So I'm as guilty as the rest of you.  When a patient gets rushed into my ICU from the general medical or surgical floor crashing and burning, I grab my glidescope and ultrasound and get suited up to insert lines and tubes all while the nurses attach the patient to an array of bedside monitors.  The exam often gets squeezed between necessary procedures and a detailed examination often gets pushed back until well after the patient has been stabilized.  Sometimes priorities like the need to establish an airway get in the way - but more often than not - the ABCs are OK and we can actually leave the monitor and pulse oximeter alone for a minute, talk to the patient, examine the patient, and use the oldest tool in EMS - our hands.

Bottom line - technology is great. It saves lives, it makes our job more interesting, and often gives us important information to guide care and to aid with making clinical decisions.   But we need to pause, put our hands back on our patients and get back to fundamentals - we need to revisit the lost art of the physical examination.  I'm not even going to get into the kumbaya side of the reassurance and compassion of a human touch - I will leave that training to you and your DO (or not). 

I recently conducted a case review in the Western Battalion that I would like to share with all of our providers.  A medic unit was dispatched in the early afternoon for reports of a 67-year-old woman with trouble breathing.  The crew arrived to find the women seated upright, in mild distress, with complaints of recent vomiting and feeling dizzy.  The patient also reported having syncope a few days prior - the cause of which was not known.  The patient denied chest pain, shortness of breath, and abdominal pain.  The GCS was 15.  Initial VS were BP 98/70, HR 110/min, RR 22/min, Spo2 96% on room air.  Finger stick glucose was 223 mg/dL.  The care plan read like so many of our emeds reports do: "O2, IV LR, monitor".  No medications were listed on the emeds report and a brief medical history including "gastric reflux, lupus, chronic fatigue, and syncope" were listed.  The patient was bolused 500 cc LR enroute to the hospital.  The crew reported that enroute to the hospital the patient felt better, skin color improved, and the patient became more alert.

Here is the 12-lead ECG that was obtained:

How do you think this ECG was interpreted?  How did you interpret it?  If you're not sure what the rhythm is - is there anything else you can do to aid in interpretation?  How might simple physical examination skills aid in making the diagnosis?

The patient was transported priority 2 to the ER and transferred to hospital staff without incident.  Review of the emeds report and ECG by the DO a few days after the incident resulted in this case being brought to my attention for review with the provider.

Where did this seasoned ALS provider go wrong?  Aside from the "O2, IV, monitor" and LR bolus - should anything else have been done for this patient?  

How could a basic EMT with only their hands have saved this ALS provider and helped clinch the diagnosis?

I look forward to your comments and will post the conclusion to this case shortly.

CONCLUSIONS:

1. Quick glance at this 12-lead ECG might lead the provider to think they are looking at a normal sinus rhythm with low voltage and an occasional PVC.  The P-waves do indeed march out at a rate of about 90/min.  However, none of these P-waves are followed by QRS complexes.  The QRS complexes that do appear do not communicate with the P-waves.  Thus, this is complete (3rd degree) heart block.

2. Usually a 12-lead ECG will give you much more information than a simple rhythm strip.  However, in this case, a longer rhythm strip would have probably made it easier for the provider to see the QRS complexes marching out independent of the P-waves.  Simply looking at a continuous lead display (i.e. lead II) on the LP15 is less ideal than printing out a 10-15 second strip.

3. Never underestimate the importance of the basics.  Always take your patient's pulse manually.  As some of you astutely pointed out - actually palpating the patient's pulse should have clinched the diagnosis of complete heart block (as only the profoundly bradycardic ventricular beats should have generated a palpable radial pulse).  It is unlikely but remotely possible that the regularly occuring atrial activity might have generated a faint carotid pulsation.

4. Pacing/debrillation pads should have been applied to the patient's chest so that transcutaneous pacing could be initiated immediately had the patient become hemodynamically unstable.

5. While atropine often does not work in complete heart block, 2013 protocols state that it may be considered after medical consultation for Mobitz type II AV block or 3rd degree (complete) AV block.