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

- Rogue Medic

What is the basis for post-resuscitation treatment recommendations?

We spend a lot of time worrying about how to get a pulse back. We spend so much time on getting that pulse back, that some of us think that producing a pulse is what matters.

Once we have a pulse back, whether using only evidence-based treatments (continuous compressions and defibrillation) or after throwing in some of the witchcraft that does not belong in the guidelines (ventilations, intubation, epinephrine, vasopressin, norepinephrine, phenylephrine, amiodarone, lidocaine, magnesium), we have no good evidence to guide treatment.
 

There is no proven benefit or harm associated with administration of routine IV fluids or vasoactive drugs (pressor and inotropic agents) to patients experiencing myocardial dysfunction after ROSC.[1]

 

This clearly rules out having any treatments categorized as Class I or even as Class IIa, but the AHA (American Heart Association) does not follow its rules for evaluation evidence. In the paragraph following the quote above, the guidelines state –
 

Fluid administration as well as vasoactive (eg, norepinephrine), inotropic (eg, dobutamine), and inodilator (eg, milrinone) agents should be titrated as needed to optimize blood pressure, cardiac output, and systemic perfusion (Class I, LOE B).[1]

 

Where is the evidence?
 

There is a paucity of data about which vasoactive drug to select first, although providers should become familiar with the differing adverse effects associated with these drugs, which might make a particular agent more or less appropriate for a specific patient.153 [1]

 

In other words, we should not select drugs because they are good, but because they do not have a lot of evidence of harm, or because we are comfortable with the excuses for the harm these drugs cause.

When presented with this kind of advice, we should always ask, What evidence do we have that any of these harmful treatments provide more benefit than harm?

In EMS, dopamine seems to be the drug of choice for shock (inadequate tissue perfusion, usually with hypotension).
 

Although low-dose dopamine infusion has frequently been recommended to maintain renal blood flow or improve renal function, more recent data have failed to show a beneficial effect from such therapy161,162 [2]

Are we asking the right questions?

Is vasoconstriction the solution to shock?

Is vasodilation the problem?
 

High doses of NTG were used in 22 patients, including 14 patients with acute MI and eight patients with advanced HF. All patients had critically low BP measured by cuff, and 18 had an unmeasurable BP and pulse.[3]

 

The doses shown are considered to be huge – even for patients who have very high blood pressures.

These patients do not have any blood pressure, or they have such very low blood pressure that it cannot be measured. The treatment is NTG (NiTroGlycerin or GTN – GlycerylTriNitrate in Commonwealth countries).

Almost any ACLS (Advanced Cardiac Life Support) instructor will tell you exactly what the result will be – death and course failure for refusal to accept the dogma of hypotension plus NTG = death.

I underlined all of the patients who received 25 mg NTG or more. A standard NTG tab is 0.4 mg. All of the underlined patients received an amount of IV (IntraVenous) NTG that is more than 60 times higher than the standard NTG dose.

In all of these patients, the blood pressure was too low to be obtained.
 


Click on the image to make it larger.

 

Almost all of the massive dose NTG patients survived.

If we are to believe the hypothesis that vasopressors are necessary to treat shock, improvement after NTG does not make sense.

If we are to believe the hypothesis that vasopressors are necessary to treat shock, improvement after huge NTG does is not possible.

Maybe we need to reconsider our beliefs.

We have developed a bias that is unduly influencing our treatment of our least stable patients.

We have developed a bias that is unduly influencing our treatment of our most easily harmed patients.

Footnotes:

[1] Vasopressors
2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
Part 9: Post–Cardiac Arrest Care
Vasoactive Drugs for Use in Post–Cardiac Arrest Patients
Free Full Text from Circulation

[2] Table 2. Common Vasoactive Drugs
2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
Part 9: Post–Cardiac Arrest Care
Vasoactive Drugs for Use in Post–Cardiac Arrest Patients
Free Full Text from Circulation

[3] High dose nitroglycerin treatment in a patient with cardiac arrest: a case report.
Guglin M, Postler G.
J Med Case Reports. 2009 Aug 10;3:8782.
PMID: 19830240 [PubMed – in process]

Free Full Text from PubMed Central . . . . . Free Full Text PDF from PubMed Central

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