do you fight a V/Q mismatch - page 2

somthing clinical for a change: I have recently read about the phenomena that exsits where patients in a (lateral recumbent position) for example will have a v/q mismatch. I qualify this with... Read More

  1. by   Tenesma
    nitric oxide will improve your V/Q mismatch... don't worry about HPV so much... just use what makes sense physiologically, and by the way TNG would be fine as well...
  2. by   TraumaNurse
    I love these discussions! Thanks guys!
  3. by   WntrMute2
    nitric oxide will improve your V/Q mismatch... don't worry about HPV so much... just use what makes sense physiologically, and by the way TNG would be fine as well...

    Can you explain how the vasodilating properties of NO helps in the face of OLV? I'm not saying it doesn't work. I've never used it in the OR, we did use a lot in the ICU for patients with poor lung function and high PA pressures, worked like a dream. But I can't figure out the physiology in the face of needing HPV. O2 sats can be so bad (as you know) that the PA must be ligated or clamped early in the pneumonectomy to eliminate that shunt flow entirely so I can't get my pea-brain wrapped around the benifits of NO or NO producing drugs in this scenerio. Tenesma?
  4. by   versatile_kat
    For all the newbies yet to be in school, could you please expand on what HPV (i'm assuming the "V" stands for ventilation) and TNG stand for? Thanks.
  5. by   Tenesma
    now let's say for some reason you can't oxygenate the collapsed lung and for some reason the surgeon can't clamp the PA feeding the collapsed lung - what are the things that will improve V/Q in the dependent lung?

    the only way around it is to cheat a tiny bit.... Nitric oxide creates vasodilation in the ventilated part of the lung, so now you are shunting more blood towards your ventilated lung and therefore get better V/Q... sounds simple... and it works... I don't use it very often in the OR though - cause it is so ridiculously expensive - and therefore use it only if the patients life is in danger - but at least it is an extra card up your sleeve. I use it a lot more often for people with acute pulmonary hypertension or especially for heart transplants into recipients with long-standing pulmonary hypertension that hasn't responded to chronic milrinone or nesitiride (natrecor).
  6. by   WntrMute2
    Quote from Tenesma
    now let's say for some reason you can't oxygenate the collapsed lung and for some reason the surgeon can't clamp the PA feeding the collapsed lung - what are the things that will improve V/Q in the dependent lung?

    the only way around it is to cheat a tiny bit.... Nitric oxide creates vasodilation in the ventilated part of the lung, so now you are shunting more blood towards your ventilated lung and therefore get better V/Q... sounds simple... and it works... I don't use it very often in the OR though - cause it is so ridiculously expensive - and therefore use it only if the patients life is in danger - but at least it is an extra card up your sleeve. I use it a lot more often for people with acute pulmonary hypertension or especially for heart transplants into recipients with long-standing pulmonary hypertension that hasn't responded to chronic milrinone or nesitiride (natrecor).

    Thanks Tenesma, for KAT, HPV = hypoxic pulmonary vasoconstriction, the tendancy for areas of the lung that are hypoxic to shunt blood to areas with better oxygenation. TNG = Nitroglycerine. OLV = one lung ventilation.
  7. by   gaspassah
    we havent studied this yet but i read a research article on this at one time. speaking of NO, are you talking nitric oxide as in liquid ventilation, i read of this in the treatment of ARDS (acute resp. distress syndrome)?
    d
  8. by   Brenna's Dad
    So am I right in interpreting your response to mean that NO only causes vasodilation in the ventilated parts of the lung? Otherwise, I would be concerned in increasing blood flow to the deflated lung as well, which might wosen your V/Q match even more. After all, perfusion is not the issue in the ventilated lung.

    But...perhaps the increase in perfusion is enough to increase your oxygenation.

    While we're on this topic... what do you all think the effect of a Neosynephrine gtt would be on your HPV. (perhaps only theoretically) I had an instructor state that this could worsen your HPV, but I'm questioning this logic just a little bit.

    As long as you are ventilating the good lung, it is HPV after all, that's assisting your oxygenation. The blood flow is shunted to those parts of the lung that are being ventilated instead of the defalted lung. If this were not so, your shunt would be even greater.
  9. by   Tenesma
    that's right... NO only causes vasodilation in ventilated lung
  10. by   Brenna's Dad
    Interesting stuff. How much systemic effect do you get from your NO?
  11. by   Tenesma
    well theoretically there are systemic effects, but we don't really see them...
    of interest, you will soon be seeing nebulized or IV Viagra to augment the effects of NO on the lungs... i am serious..
  12. by   Brenna's Dad
    Phospodiesterase inhibitors... the wave of the future.

    I guess we can assume that the phospodiesterase responsible for metabolism of cAMP in genital vasular smooth muscle is the same that in the pulmonary vascularture.

    Now is that Phosphodiesterase 7 or 9?? (hehe)
  13. by   Tenesma
    close but no cigar... pulmonary wise it is PDE-5 all the way - in fact the lung is the main place for PDE-5, and that is why viagra is so perfect for the lung... it is working great so far in studies (being done by my colleagues) in sheep...

    they may have to change the trade name though before they start marketing it

Must Read Topics


close