Platypnea-orthodeoxia:
* What's that you say?
- dyspnea and deoxygenation when moving to SITTING UPRIGHT from supine
= wait, that's not normal!
= improved with lying FLAT
- due to INTRAPULMONARY shunting when moving UPRIGHT
- suspect with:
= hepatopulmonary syndrome
- possible mechanism of vasodilation and thus increased perfusion of capillaries at lung BASES (which are least oxygenated)
- liver cirrhosis- see this in ~40% of cirrhotic patients
- portal HTN
- hepatitis
- look for finger clubbing!
- pulmonary congestion at bases
= AV shunting
= ASD or PFO w/ shunting
= ARDS
= rare causes
- Pericardial effusion/restrictive pericarditis
- Significant PE load
- Ileus
* Why do I care?
- Treatment in the ER:
- Increased mortality in cirrhotic patients especially with PO2 <60mmHg
- LIVER TRANSPLANT: definitive (but lower post-transplant survival)
- TIPS: decrease shunting, improved gas exchange (theoretical)
- Nitric Oxide Synthesis inhibition or TNF inhibition: no evidence yet
- MDM:
- not all respiratory distresses = CHF, pneumonia or PE
- consider extra-pulmonary contribution to SOB
- not all treatments will work all the time
- keep an eye out for variation and be suspicious something else is going on