Oxygen!
It's one of the most basic interventions we provide at all levels of EMS.
COVID has changed how we think about oxygen delivery.
Many COVID patients need oxygen.
We know that certain oxygen delivery methods can put us at risk...
So what ARE the best recommendations for providing oxygen to pre-hospital patients???
And why do we need to make changes?
First the why.
COVID is a respiratory pathogen. This means is PRIMARILY spreads via respiratory droplets- the little tiny balls of spit we constantly spew into the air when we talk, cough, sneeze (or sing...https://www.businessinsider.com/two-people-dead-from-coronavirus-after-super-spreading-event-2020-3).
UNDER CERTAIN CONDITIONS, these droplets can become teeny tiny and instead of settling down, become more readily spread in the air. This is essentially what "airborne" means. COVID does not do this very readily on its own, but some things WE do CAN cause it to become airborne.
Procedures that cause COVID to become airborne (aerosolizing procedures) include nebulizers, high flow oxygen, BVM, CPAP. Potentially when we doff PPE after an event like a code, we could shake small amounts into the air.
Now, the what:
What's an EMS provider to do? How can we care for our sickest patients AND protect ourselves and our crews from airborne particles??
We have created the following "cheat sheet" to provide best practice information on the types of oxygen administration we encounter in the field. Use this as a reference- it is designed to be brief and succinct. We plan more posts to discuss particular topics in greater detail...stay tuned and stay safe!
COVID
oxygen and airway cheat sheet for EMS
Oxygen administration
General:
-Early oxygen for ANY respiratory distress when COVID is possible
-Goal should be ≥90%, not 100% (92-93% in pregnant
patients)
-Silent hypoxia is a hallmark of COVID; pts can have sats as low as
78% and not appear dyspneic
-Aerosol generating procedures include: nebulizers, CPAP,
BVM/CPR, high flow nasal cannula
-Truck ventilation should be non-circulatory mode, with rear
exhaust fan used to draw air away from driver
Nasal Cannula
-Up to 6L NC does not aerosolize.
- Recommended to put
surgical mask OVER cannula at all times
>6L creates aerosol-must vent truck and use max PPE
NRB
-MUST ensure a tight fit with mask
-Use surgical mask over to cover side ports
- With tight seal and mask over ports, not thought to generate significant
aerosol
CPAP
-No longer first line but still consider for patients in
extremis
-Must use max PPE
-Creates significant aerosol but can minimize it by using
HEPA filter with a good seal
-Consider administering outdoors long enough to stabilize,
then transition to NC or NRB
-If pt on CPAP, stage in ambulance until you communicate
with ED for transport plan into department
Nebulizers
-AVOID if possible
-Instead of neb: MDI with spacer
-Subcutaneous epi for patients in severe distress (first
dose within protocol; more doses require med control for A-EMT)
-If neb necessary, consider giving outdoors prior to
transport
-DISCONTINUE any nebs prior to
entering emergency department
Airway management
Cardiac arrest
-BVM is an aerosolizing procedure- MAX PPE for all codes
-Place SGA as soon as possible to avoid BVM alone
-Attach BVM to SGA prior to placement -use HEPA filter if
available
-REMEMBER ALL personnel that are in same room or compartment
with patient must be in full PPE (don't forget LEOs, bystanders)
-Stage in ambulance on arrival until you communicate with ED
staff for transport plan
Intubation
-Discouraged due to considerable aerosol risk to provider;
RSI best and not widely available for pre-hospital
-Video laryngoscopy preferred method
-Pre-oxygenate as much as possible
-Most experienced provider should do airway- take a minute
to prepare so you have best chance of first pass success
-Beware- patients with ARDS (esp young/old/pregnant) can
decompensate QUICKLY once intubated.
BVM
-Tight seal, HEPA filter to minimize aerosol
-COVID patients with resp arrest likely have an ARDS picture
-Appropriate ventilation in ARDS MUST avoid hyperventilation
and baritrauma
-Avoid barotrauma by bagging with two finger technique (Why?—the
typical adult BVM has a 1-2 L capacity. The average ideal tidal volume for an
adult is HALF that. Compressing the BVM fully leads to over-inflation of the
lungs & barotruma->increased intrathoracic pressure-> decreased
preload->worsening hypotension-> overall mortality increase
-Use a PEEP valve if available
Stay tuned for more COVID-related clinical information.
Stay safe!
Resources:
Maryland Airway and Respiratory Considerations for the EMS
Clinician: https://www.miemss.org/home/Portals/0/Docs/Infectious_Diseases/COVID-19-Airway-and-Respiratory-Management-Considerations-20200325.pdf?ver=2020-03-25-154521-457
SAS consensus statement on airway management in COVID:
WHO clinical management guidelines for COVID:
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