New and Future Trends in EMS

Ron Brown, MD, FACEP

Paramedic Lecture Series 2018

New technologies and protocols

• DSD

• Mechanical Compression

• ITD

• BiPAP

• Ultrasound

Double Sequential Defibrillation

• Two defibrillators delivering non-synchronous shocks closely spaced

• Believed that the differing vectors, rather than increased energy or area of myocardium covered, is what provides benefit

• Decades old use by cardiology for cardioversion in refractory Afib

• EMS usage: refractory VF defibrillation

• Sequential as opposed to simultaneous theoretically does two things: • Prevents cancelling the vector wave

• Prevents electricity from one unit damaging the circuit board of the second

• Unknowns: • Ideal pad placement

• Ideal timing

• Risk to equipment • Officially off-label

• Need to run and document maintenance check afterward

• AP & A-apex

Mechanical Compression Devices

• Concept goes back decades

• Consistently found to not be superior to human compressions (CIRC, LINC) • Piston type (LUCAS)

• Load distributing band (AutoPulse)

• Device position is crucial

• Autopulse vs Lucas vs manual CPR

• Found that piston devices (Lucas) did not result in more visceral injury than manual CPR

• Found that compression band (Autopulse) induced increase in visceral injury “could not be excluded”

When to use?

mCPR Indications

• During transport • Restrictive environment: helicopters, small fixed wing

• EMS personnel safety in moving rig

• Refractory VF • Transport to CVL without ROSC

• Post-ROSC • Apply prior to initiating transport

• Recurrent arrest

Impedance Threshold Device

• Use during CPR, meant to decrease intrathoracic pressure, thereby increasing venous return • Restricts inflow of air into chest during recoil phase*

• Animal models showed increased perfusion to brain and heart

• Current randomized trials do not show improved ROSC or neurological outcome in clinical medicine • Latest meta-analysis (2015)

• Latest animal models continue to show improved hemodynamics (2014)

Hypothesis and Data

Noninvasive Positive Pressure Ventilation

• Continuous Positive Airway Pressure is commonly used • Requires spontaneous ventilations and airway protection

• Helps increase diameter of dead space airway, recruit alveoli. Increased Functional Residual Capacity

• Decreases venous return—good for pulmonary edema

• Ventilatory support traditionally requires BVM or a tracheal airway + bag

IPPV vs NPPV

• NPPV requires airway protection by the patient • Spontaneous respirations

• Adequate mental status

• IPPV (e.g. ETT + ventilator) requires no patient effort • Airway protection (never 100%)

• No diaphragm or accessory muscle use needed

Downside IPPV

• Increased morbidity and mortality • Increased risk of aspiration

• Increased virulence of pathogens in CCU

• Mechanical path from CCU atmosphere into trachea

• Deconditioning of respiratory muscles

• Required use of sedation: iatrogenic encephalopathy

NPPV: BiPAP

• Bilevel Positive Airway Pressure: CPAP + increased pressure when ventilator senses a drop in system pressure as the patient initiates inhalation • So, does require some use of negative pressure (normal) respiration

• Improves airway diameter, alveolar recruitment, preload reduction • Pressure Support during a breath increases these parameters

• Greater oxygen delivery

• Increased mixing of carbon dioxide, and exhalation as PS decreases to PEEP, CO2 richer air exits the chest

• Marked improvement in hypercapneic encephalopathy

• Pressure Support vs Assist Control • PS relies on intact ventilation

• AC (also called CMV—continuous mechanical ventilation) sets a tidal volume and rate (thus the minute volume)

Zoll AEV, EMV+

• Ventilators combining traditional ETT modes with CPAP and BiPAP • Can be set in Assist Control, most likely used in BL (Pressure Support)

Ultrasound in EMS

• Ultrasound use is expanding markedly beyond use by Radiology • Nursing: difficult peripheral vascular access

• Emergency medicine: vascular access, FAST for trauma, guidance for various aspiration procedures (paracentesis, arthrocentesis, thoracentesis), abscess evaluation, pneumothorax evaluation, cardiac evaluation (particularly arrest situations)

• Critical care medicine

• Trauma surgery

Possible Prehospital Uses

• Detection of pneumothorax—belay that dart!

• Cardiac • Visualization of cardiac activity in termination of resuscitation

• Cardiac tamponade

• AAA

• Vascular access

• Downgrades

Possible Prehospital Uses

• Detection of pneumothorax—belay that dart!

• Cardiac • Visualization of cardiac activity in termination of resuscitation

• Cardiac tamponade

• AAA

• Vascular access

• Downgrades not really

Pneumothorax

• http://rebelem.com/ultrasound-detection-pneumothorax/

• Detecting : • Ultrasound: sensitivity 86-98%, specificity 97-100%

• AP CXR: sensitivity 28-75%, specificity 100%

http://rebelem.com/ultrasound-detection-pneumothorax/http://rebelem.com/ultrasound-detection-pneumothorax/http://rebelem.com/ultrasound-detection-pneumothorax/http://rebelem.com/ultrasound-detection-pneumothorax/http://rebelem.com/ultrasound-detection-pneumothorax/http://rebelem.com/ultrasound-detection-pneumothorax/

Cardiac Activity

Tamponade

AAA

IV Access

Barriers to Prehospital Ultrasound

• Cost • Unit + probes

• Three types of probes but can get by with two

• Typically probes are $8,000 each

• Expertise • Training