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 in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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