Arterial Hyperoxia Following Resuscitation Linked to Mortality

Street Science team discusses this new study

 

 
 
 

Keith Wesley, MD, FACEP | Marshall J. Washick, BAS, NREMT-P | | Friday, July 16, 2010


Review of: Kilgannon JH, Jones AE, Shapiro NI, et al. Association between arterial hyperoxia following resuscitation from cardiac arrest and in-hospital mortality. JAMA. 2010;303:2165–2171.

The Science
This large, prospective observational study investigated the association between elevated arterial oxygen levels (hyperoxia) and increased hospital mortality post-resuscitation from cardiac arrest. The data was pulled from the Project IMPACT database, which encompasses 120 intensive care units (ICUs) across the U.S. Hyperoxic patients (defined as PaO2 of > 300 mmHg) were compared against those who were hypoxic (defined as PaO2 < 60 mmHg) and normoxic post-cardiac arrest. A total of 6,326 patients were eligible for review: 1,156 were hyperoxic, 3,999 were hypoxic, and 1,171 patients were normoxic with mortality rates of 63%, 57% and 45%, respectively. The investigators were able to show that hyperoxic states are associated with increased risk of death.

The Street
Medic Marshall: Reading this study was a real eye-opener for me with regard to the potential lethality of oxygen. How many times do you show up on a scene—any scene, for that matter—and your first responders have a non-rebreather mask on your patient? This patient just so happens to be complaining of stomach cramps, isn’t short of breath and isn’t complaining of chest pain or dizziness … well, you get the picture. Yet this study was able to show that too much oxygen post-resuscitation might actually be killing people.

Here’s a more likely scenario: You roll up on a cardiac arrest to find the patient being ventilated at rate of 40 plus breaths per minute with 100% oxygen. We already know patients are being hyperventilated, but now hyper-oxygenated? I find this a little scary, personally. I also don’t know how to address the issue.

So what does this all really mean? Do we stop administering oxygen in high doses to everyone? Are there only certain conditions under which oxygen should be administered? I don’t know, but it would sure seem that way.

Doc Wesley: Our understanding of cardiac arrest physiology continues to significantly expand with research such as this. There’s a growing body of science to indicate that oxygen is not a benign drug. This concept runs counter to our longstanding prolific use of oxygen in every Department of Transportation and National Highway Traffic Safety Administration curriculum since their inception in the 1970s.

However, the U.S. has lagged behind the recommendations of such notable organizations as the British Thoracic Society. They released guidelines for oxygen administration in 2008 that prescribed that there’s no reason to exceed an oxygen saturation of greater than 96%.

In the study, the data clearly showed a significant increase in mortality when the arterial oxygen content exceeded 300 mmHg and, in fact, was worse than that of patients who were hypoxic. Additionally, the neurologic status of survivors was worse if they experienced post-arrest hyperoxemia.

The theory is that during ischemia there are several protective mechanisms the body uses to inhibit cell death. These anti-inflammatory and antioxidant responses are inhibited by high concentrations of oxygen, particularly immediately after perfusion is restored. In this study, the first measurement of arterial oxygen content was made when the patient arrived in the ICU, which was more than likely an hour or more after return of spontaneous circulation (ROSC).

Although this study may appear to have more impact on emergency department care of the cardiac arrest patient, the fact that animal data indicates that oxygen causes cellular damage immediately following ROSC may force us to consider titrating oxygen delivery in the field. This will be problematic because few EMS providers are equipped with variable oxygen concentration delivery systems.

It will be interesting to see if the 2010 American Heart Association guidelines address this issue.




Connect: Have a thought or feedback about this? Add your comment now
Related Topics: Patient Care, Cardiac and Circulation, Airway and Respiratory

 
Author Thumb

Keith Wesley, MD, FACEP

Keith Wesley, MD, FACEP, is the Minnesota State EMS medical director and the EMS medical director for HealthEast Ambulance in St. Paul, Minn. and and can be reached at drwesley@emsconsulting.net.

BROWSE FULL BIO & ARTICLES >

Author Thumb

Marshall J. Washick, BAS, NREMT-Pis a paramedic and the peer-review/research coordinator for HealthEast Medical Transportation. He can be contacted at MjWashick@HealthEast.org.

BROWSE FULL BIO & ARTICLES >

What's Your Take? Comment Now ...

Featured Careers & Jobs in EMS





 

Get JEMS in Your Inbox

 

Fire EMS Blogs


Blogger Browser

Today's Featured Posts

 

EMS Airway Clinic

Innovation & Progress

Follow in the footsteps of these inspirational leaders of EMS.
More >

Multimedia Thumb

Buffalo Medics, Firefighter Keep Working in Crash

Rural Metro medics describe crash that overturned their ambulance.
Watch It >


Multimedia Thumb

Drone Delays Landing of Ohio Medical Helicopter

Miami Valley Hospital incident raises questions over legalities of drones.
Watch It >


Multimedia Thumb

Four Killed in New Mexico Medical Plane Crash

Crash near fairgrounds claims patient and crew of three.
Watch It >


Multimedia Thumb

Texas Ambulance Involved in Crash

Odessa ambulance and car collide during response.
Watch It >


Multimedia Thumb

New Mexico Air Ambulance Crash

NTSB investigates crash that killed four.
More >


Multimedia Thumb

Where in the World of EMS is A.J.? Scranton

JEMS Editor-in-Chief visits his hometown of Scranton, Pa.
More >


Multimedia Thumb

Braun Ambulances' EZ Door Forward

Helps to create a safer ambulance module.
Watch It >


Multimedia Thumb

The AmbuBus®, Bus Stretcher Conversion Kit - EMS Today 2013

AmbuBus®, Bus Stretcher all-hazards preparedness & response tool
Watch It >


Multimedia Thumb

LMA MAD Nasal™

Needle-free intranasal drug delivery.
Watch It >


Multimedia Thumb

Field Bridge Xpress ePCR on iPad, Android, Kindle Fire

Sneak peek of customizable run forms & more.
Watch It >


More Product Videos >