Hypoxia in setting of patient with kown liver disease and likely Pulmonary HTN
Less common complication of Cirrhosis/ESLD (est 4-47%)
Increased Arterial to alverolar O2 gradient
Pulmonary Vascular Vasodilation
Underlying Liver Disease
Type 1: Increasesd circulating vasodilators such as nitrous oxide, leading to vasodilation in capillary and precapillary beds of the lungs
Type 2: AVM’s
Overall patients have an increased in total number of dilated vessels
Platynea: Dyspnea when sitting up and relieved lying down
Orthodeoxia: Decreased arterial O2 tension (>4mmHg) or arterial oxyhemoglobin desaturation of >5% from lying to upright
Hypoxemia (not specific)
Liver disease present
O2 Therapy will temporarily improve patients with type 1 but not type 2 (because it is an AVM)
Contrast enhanced echocardiogram is preferred study for diagnosis–> contrast injected if normal will only opacify right chambers of the heart because they will be filtered by pulmonary capillary bed.
Intracardiac shunt is demonstrated if contrast is visualized in L heart within 3 beats. Intrapulmonary shut (as in hepatopulmonary syndrome) will occur slightly later after 3 beats and usually within 3-6 beats
TEE is a better study but also more invasive and is contraindicated in patients with varices
Type 1 patients can be offered improvement of symptoms with oxygen.
Type 2 patients will require embolization as O2 therapy does not offer any relief in the setting ov AVM’s
Definitive treatment for both is Liver transplant.
Resources: UpToDate & Principles of Critical Care (Sonali Sakaria & Ram M. Subramanian)