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This case study explores a patient with persistent post-operative hypoxia in the ICU, ultimately diagnosed with hepatopulmonary syndrome. Symptoms included platypnea and orthodeoxia, and the patient required long-term oxygen therapy.
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Persistent post-op hypoxia ICU, Pamela Youde Nethersole Eastern Hospital Dr Emily Cheung & Dr Arthur CW Lau 24 Sep 2010
Case • M/69, ADLI • Ex smoker, drinker • PMH: • eAg negative chronic hep B • Ulcerative colitis on mesalazine • HT
Newly diagnosed HCC over right lobe • ‘C’ adm for open right hemi-hepatectomy • Uneventful operation • Intra-op finding: • Large tumor at seg V of liver • Liver not cirrhotic macroscopically
Post op extubated and transferred to ICU for monitoring • Post op on 6L O2, gradually tail down O2 requirement • On 2L O2 without SOB on discharge • Discharge from ICU on D1
Developed abdominal distension with post-op ileus on D3 • Increasing O2 requirement and desaturation noted in general ward • Readmitted ICU on D4 • Required 12 L O2 on admission to ICU • ABG on O2: unremarkable
CXR and CT reviewed • suggestive of some atelectasis in dependent part of both lower lobes • Probably contributed by bowel distension • No evidence of PE or chest infection
Progress • NIV given for a short period of time, but not very responsive • Chest physio with lung expansion by incentive spirometry started • However, still noticed occasional desaturation • ? Causes for persistent hypoxaemia
Detailed history taking • Complaints of discomfort on sitting up while watching TV, feels better if lying down • Symptoms present for 2 years • P/E: • No Stigmata of chronic liver disease • No clubbing, spider naevi • No gynecomastia
Patient complaints SOB while sitting up, relieved by lying Platypea • More than three repeated trials of SpO2 measurement on 3L O2 Orthodeoxia • Lying: SaO2 > 93% • Sitting: Desaturated with SaO2 down to 81%, not fully correctable by increasing FiO2
Bedside Echo with contrast by ICU Team • Chamber sizes relatively normal • Presence of intrapulmonary shunt, as indicated by bubbles on left side after 3rd beat • Ddx: • Intrapulmonary/Intracardiac shunt • More likely intrapulmonary shunt because bubbles did not occur immediately on L side post-bubble contrast injection • Discharged from ICU on D8 • Reviewed by medical team
Progress • Inpatient Echo repeated by Cardiac team on D14 • mild pul hypertension • Bubbles contrast was seen in LA and LV after injection, suggested the presence of right to left shunt • no definite intra-cardiac shunt was detected • Ddx: intra-cardiac/intrapulmonary AV shunt • Patient refused TEE
Impression of the causes of hypoxemia • Hepatopulmonary syndrome, and • Atelectasis due to bowel distension
Hepatopulmonary syndrome • Characterized by a defect in arterial oxygenation induced by pulmonary vascular dilatation in the setting of liver disease • Trial of • Liver disease • Pulmonary vascular dilatation • Defect in oxygenation
Source: Roberto Rodríguez-Roisin, M.D., and Michael J. Krowka, M.DHepatopulmonary Syndrome — A Liver-Induced Lung Vascular Disorder. NEJM, Volume 358:2378-2387 May 29, 2008 Number 22
Clinical features • 18% asymptomatic • Platypnea : • Dyspnea improves when lying flat • Orthodexoia: • Hypoxemia worsens upon sitting up and improves when lying flat • pO2 decreased by > 5% or > 0.5 kPa
Opacification of right atrium and right ventricule with microbubbles and delayed opacification of the LA and LV
Pathobiology • Gross dilatation of the pulomonary precapillary and capillary vessels • Absolute increase in no of dilated vessels • Pleural and pulmonary AV communications and portopulomonary venous anastomoses
Dilated capillaries not uniform blood flow • Venous blood passed rapidly or directly thro intrapulmonaryshunt to pulmonary veins • VQ mismatch
Treatment • No effective medical therapies • Liver transplantation is the only successful treatment • pO2 < 60 mmHg is considered to be an indication for liver transplantation • Long term oxygen therapy • For symptomatic patients with severe hypoxaemia