Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

The Parachute Study as an Objection to Studying Ventilations in Cardiac Arrest

 
The use of ventilations in cardiac arrest is an example of a treatment that some of us defend by reference to the parachute study.

We assume that we understand all we need to know about physiology, thus we overestimate our ability to understand what we are doing.

Is it impractical to compare the effects of compression-only CPR with standard CPR?
 

It doesn’t take a PhD physiologist to know that at SOME point you have to provide some ventilation, or 02 sats will decrease, CO2 will increase, etc., to unsurvivable levels. Before you buy the “never been researched ergo must be bad,” you have to read http://www.bmj.com/content/327/7429/1459.full

No, there has never been a prospective, randomized trial of the parachute, but does that make the use of parachutes any less valid?

 

Is compression-only CPR the same as throwing the patient from a plane without a parachute?

Of course not, but suggesting that traditional treatments are not essential does seem to encourage the use of logical fallacies in otherwise intelligent people, even those trained to the doctorate level especially those trained to the doctorate level.

How much bias is necessary to jump to the conclusion that the criticism of our evidence-free traditional treatments is the same as claiming that the treatment must be bad?

The decision to continue to use treatments of unknown benefit and unknown harm is what is bad.

The list of treatments we have abandoned after we finally examined the treatments, and found out the traditional treatments were harmful, is not short.

We killed a lot of people with ignorance and appeals to common sense.

We still do.
 


 

The decision to remain ignorant is a bad decision for us, but a much worse decision for our patients.

What evidence do we have that ventilations improve survival from cardiac arrest?

None.

We assume this.

Is any ventilation provided by continuous chest compressions?

The comment above suggests that there is no ventilation, or that the ventilation is completely inadequate for the physiologic needs of a dead patient.

Is it reasonable to treat patients based on those assumptions?

Is it ethical to treat patients based on those assumptions?
 

It doesn’t take a PhD physiologist to know that at SOME point you have to provide some ventilation, or 02 sats will decrease, CO2 will increase, etc., to unsurvivable levels.

Is that point at any time before ROSC (Return Of Spontaneous Circulation)?

Maybe.

Maybe not.
 

Conclusions
This report demonstrates that if powerful cardiac compressions are started early, in this case less than two minutes after normothermic arrest, it is possible to maintain circulation and a sort of spontaneous respiratory movements resulting in gas exchange for more than 25 minutes. For this patient, this kind of respiration was sufficient for survival without neurological damage.

Favourable outcome after 26 minutes of “Compression only” resuscitation: a case report.
Steen-Hansen JE.
Scand J Trauma Resusc Emerg Med. 2010 Apr 16;18:19.
PMID: 20398354 [PubMed – indexed for MEDLINE]

Free Full Text from PubMed Central

 

Unless there is evidence of benefit, an intervention should not be presumed to be benign.

 

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Comments

  1. These people that argue that ventilations are obviously necessary also miss the fact that performing ventilations almost always means some interruption in compressions. As a result, for ventilations to be truly beneficial, they not only need to have some benefit, but have more benefit than the corresponding 10 seconds of compressions would have had.

    Honestly, this idea should be applied to all interventions for cardiac arrest. The real question shouldn’t be “Does this help at all?” but rather “Does this help more than the resulting interruption in compressions hurts?”

  2. Positive pressure ventilation is very different from spontaneous respiration: the increased intrathoracic pressure (when a spontaneous breath causes DECREASED intrathoracic pressure) is known to be a factor in hemodynamics of ventilated patients in the ICU, ie decreased preload due to pressure on the vena cava. How can we think that affecting intrathoracic pressure in the most severe low-flow state, cardiac arrest, is a benign intervention?

    • Josh,

      Also well put.

      How can we think that affecting intrathoracic pressure in the most severe low-flow state, cardiac arrest, is a benign intervention?

      How can we think that?

      As long as we don’t examine what we believe, we can believe in any nonsense we find satisfying.

      We kill people with our belief that A pulse is a person is a save and the hospital is killing our patients.

      .

  3. Ok, going along with this, why not just omit the IV, or more recently huge push for IO in cardiac arrest. Why not just do CPR with some ventilations at a yet to determined time into the arrest and after ROSC? Why can’t we study that somehow?

    • Can’t say, clowns will eat me,

      Ok, going along with this, why not just omit the IV, or more recently huge push for IO in cardiac arrest.

      That could easily be done.

      The AHA states clearly that there is no evidence that drugs or ventilations (or any combination of drugs, or any combination of drugs and ventilations) improve survival.

      We should only be looking at evidence that looks at ROSC, or perfusion, or anything else as something that is only a preparation for survival studies. Any other approach is not an approach that can be expected to benefit patients.

      Since there is no evidence that any of these treatments improve survival, there is a state of equipoise.

      If anyone disagrees with me, provide some evidence that any of these treatments, or any combination of these treatments improve survival.

      Equipoise is one prerequisite.

      A good study design is another.

      Funding is a third.

      IRB approval is a fourth.

      Avoiding a media/political misinformation campaign, as happened in the Jacobs study, is also important.

      Why not just do CPR with some ventilations at a yet to be determined time into the arrest and after ROSC? Why can’t we study that somehow?

      Ethics is not about why not do this to some patient(s) and hope that it works.

      Ethics is about being able to justify our treatment of our patients.

      Why not? is unethical.

      .

  4. I like that this study exists and i have shared it with my forward thinking coworkers, but i have to say, 22 minutes maintaining that rhythm makes you wonder how probable is it that we will see patients presenting this way often. Seems a bit of chance that he was able to maintain that and didnt go into asystole

    I am pushing our medical director to allow NRB only and forgo airway management for the first arriving crew, but its slow going. And one case is not going to change

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