Nitric oxide in CHF patients

[JPINFV]

So I'm studying for my next A/P exam and one of the points was that NO is used for pulmonary vascular control. This got me thinking (danger Will Robinson, danger), could NO be useful in patients suffering from pulmonary edema?

By causing vasodialation, pulmonary blood pressure would drop, lowering the pressure forcing fluid into the lungs. In addition, it would be a local affect so it shouldn't compromise systemic blood pressure if the patient is hypotensive. Now I'm sure that I'm missing a rather large piece of the puzzle (difficult drug to manage, it doesn't quite work that way, but thanks for playing, etc), but I have found some interesting studies [its amazing how random side thoughts crowd out any motivation to study].

On the other hand, if you decrease pulmonary blood pressure, it might interfere with treatments like CPAP [PA increases with CPAP which would be bad if PA increases past PV, thus preventing flow through the capillaries], which would defeat the purpose of CPAP, a proven treatment option.

Review article: NO works for the short term, but it doesn't show any changes in mortality. Evidence is of poor quality anyways.

Research Study: It works, but we only tested it on 8 patients (with 8 controls)

So, would NO be a possible prehospital treatment option? Would it be a possible treatment for frontier/remote BLS units with long distant transports when used in conjunction with online medical control [note: this is not a "I want more toys" argument. Short transport/paramedic response times wouldn't necessitate this as an option. Yes, any pulmonary edema call should have medics, but let's stay in present day reality]?

[gvandellen]

Not sure about NO but look up Helox and there might be a similarity between them are some other info for research.

[AZCEP]

I can appreciate the thought process, but there would be issues with administration of nitrous oxide for the situation you describe. Since it is self-administered, and will reduce the FiO2 in use, it would not be realistic to expect great changes in patient condition from using it.

NTG works in a similar manner, but on the capacitance vessels to allow the reduction in preload you are looking for. The pulmonary vessels really don't have enough volume to make a big difference.

[VentMedic]

Nitric Oxide in preHospital? NO. It is definitely not a gas you want to mess with unless you have some differential clinical data and serious education on all components of the disease process and NO. Each medication the patient is on must be noted and regulated prior to administration. The initial investment for the special delivery system and tanks can be in the 6 digits. We rent a lot of our equipment due to the initial cost and that it will probably be out dated next year like computers. Each tank is very expensive and must be recouped through reimbursement which would be difficult in prehospital since the need for it must be make through differential diagnostics including an echocardiogram. NO should be titrated to PAP and SvO2 monitoring which prehospital would not have a PA catheter, RA line or time to do differential blood gases. The cost also makes it difficult to get in the hosptial situations. Very few hospitals have NO capability. Prostacyclins such as Flolan and Iloprost are also used in the hospital but not that wide spread yet.

You do not always see instant results with NO. If the patient has profound hypoxemia in the field there may be many etioloigies causing it. Knowing the V/Q mismatch would be important since PNA or almost any insult to the Cardiopulmonary system can exacerbate CHF with or without PH. Even with NO as supportive or treating PPH, it may take days for the PH to resolve if there are other underlying causes.

Of course, there are good possibilities that you will run into home care patients on NO, Flolan and Iloprost (Ventavix).

The studies for NO and CHF now are looking at the relationship between endogenous NO to the basal vasomotor tone of the peripheral vessels in the CHF patients and if it varied according to the plasma BNP level. For most patients, the body seems to adjust accordingly.

NO is being trialed for people with CHF and endothelial dysfunction found in some ethnic groups.

Nitric Oxide has been used in NICUs since the 1980s when the majority of the clinical trials started. For adults, the clinical trials started in the late 1980s and early 1990s.

Since these studies are usually done through the RT departments:

www.rcjournal.com has articles and abtracts of current research projects.

Diagnosis and Management of Pulmonary Arterial Hypertension:

http://www.rcjournal.com/contents/04.06/04.06.0368.pdf

Congestive Heart Failure: Diagnosis, Pathophysiology, Therapy

http://www.rcjournal.com/contents/04.06/04.06.0403.pdf

Aerosolized Prostacyclins

http://www.rcjournal.com/contents/06.04/06.04.0640.pdf

Retrospective Studies and Chart Reviews

http://www.rcjournal.com/contents/10.04/10.04.1171.pdf

Heliox is used because it is less dense and can replace nitrogen to reduce airway resistance.

[JPINFV]

Thanks, I figured I was missing something and oversimplifying it a bit.

[VentMedic]

Another thing to consider would be finding a medical director who has experience in NO since it is not used in the ED. It usually requires the expertise of a Pulmonologist and/or intensivist to manage the protocol which can get lengthy depending on the patient population. The same in the hospitals. Then, the ED RNs would all have to be familiar with the protocols and the hospital would have to have the equipment. Many RT departments can budget for it but some doctors are still reluctant to dive in.

[Doczilla]

Just to clarify, we're talking about 2 different things here: nitRIC oxide, which is an endogenous chemical that causes localized vasodilation, and nitROUS oxide, which we commonly know as laughing gas and may use for prehospital pain control. Wanted to make sure we're all staying on the same page.

'zilla

[VentMedic]

Nitrous Oxide is N2O. This has been available to Paramedics in the field for at least 25 years in some areas for pain control.

Nitric Oxide - NO is currently used in the various ICUs on a selective basis and can be done on Specialty interfacility transports.

Nitrogen - N2 is also used in NICU for subambient O2 delivery and can be done on Specialty Transport.

Nitrogen Dioxide - NO2 causes lung edema.

Nothing like a little basic chemistry to help in the medical fields.

[Just Plain Ruff]

nice little supplemental education piece for you all.

http://users.rcn.com/jkimball.ma.ultranet/...Pages/N/NO.html

[VentMedic]

And for more reading on the subject Nitric Oxide:

INOmaxTM (nitric oxide) for inhalation

http://www.fda.gov/cder/foi/label/1999/20845lbl.pdf

Nitric Oxide in Adult Lung Disease

http://www.chestjournal.org/cgi/content/full/115/5/1407

Inhaled Nitric Oxide Therapy in Adults

http://www.temple.edu/imreports/ReadingLis...O-NEJM-2005.pdf

Inhaled Nitric Oxide for High-Altitude Pulmonary Edema

http://content.nejm.org/cgi/content/full/334/10/624