Hepatopulmonary Syndrome
OVERVIEW
- Hepatopulmonary Syndrome = hepatic dysfunction + intrapulmonary vasodilation -> gas exchange abnormalities
- imbalance between intrapulmonary vasoconstriction and vasodilation at the pre- and post-capillary level
- ?NO mediated (increased NO synthetase activity)
- rarely due to an anatomic shunt
CLINICAL FEATURES
- liver disease (cirrhosis or noncirrhotic portal hypertension)
- SOB
- platypnea
- orthodeoxia
- clubbing
- cyanosis
- spider naevi
INVESTIGATIONS
- must rule out other causes of hypoxaemia: COPD, pneumonia, CHF, massive ascites -> atelectasis, pleural effusions
- PaO2: decreased on standing -> improves in supine position (orthodeoxia)
- DLCO: decreased
- technetium-Tc99 macroaggregated albumin scan: intrapulmonary shunt
- ECHO with bubble contrast: delayed visualisation in left heart = intrapulmonary shunt, immediate visualisation in left heart = intracardiac shunt
- PAC: normal to low PAP, low pulmonary vascular resistance, high Q -> different from portopulmonary syndrome (high PAP +/- PVR + elevated Q)
- pulmonary angiography: can delineate generalized and focal disease that can be embolized
Diagnostic criteria
- chronic liver disease
- arterial hypoxaemia (PaO2 < 75mmHg or A-a gradient > 20mmHg)
- intrapulmonary vascular dilation
MANAGEMENT
- many medical treatments tried -> none validated (methylene blue, indomethacin, octreotide, garlic powder, antimicrobials)
- angiographic embolization
- generally considered an indication for liver transplantation (80% improve)
PROGNOSIS
- 1 in 3 die at 1 year post-transplant
- mortality related to refractory hypoxia; also MODS, ICH and sepsis due to bile leaks
- resolution takes months (vascular remodelling)
REFERENCES
- Parker C. Ultrasound Case 111. LITFL
- Bansal K, Gore M, Mittal S. Hepatopulmonary Syndrome. StatPearls
- Hopkins WE, Waggoner AD, Barzilai B. Frequency and significance of intrapulmonary right-to-left shunting in end-stage hepatic disease. Am J Cardiol. 1992 Aug 15;70(4):516-9.
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
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