1. Persistent post-op hypoxia
ICU, Pamela Youde Nethersole Eastern Hospital
Dr Emily Cheung & Dr Arthur CW Lau
24 Sep 2010

2. Case M/69, ADLI Ex smoker, drinker PMH: eAg negative chronic hep B
Ulcerative colitis on mesalazine HT

3. 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

4. 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

5. 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

7. CT – lung window

8. 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

9. ? Causes for persistent hypoxaemia
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

10. 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

11. 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

12. 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

13. 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

14. Impression of the causes of hypoxemia
Hepatopulmonary syndrome, and
Atelectasis due to bowel distension

15. 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

16. Source: Roberto Rodríguez-Roisin, M. D. , and Michael J. Krowka, M
Source: Roberto Rodríguez-Roisin, M.D., and Michael J. Krowka, M.DHepatopulmonary Syndrome — A Liver-Induced Lung Vascular Disorder. NEJM, Volume 358: May 29, 2008 Number 22

17. Clinical features 18% asymptomatic Platypnea : Orthodexoia:
Dyspnea improves when lying flat
Orthodexoia:
Hypoxemia worsens upon sitting up and improves when lying flat
pO2 decreased by > 5% or > 0.5 kPa

18. Opacification of right atrium and right ventricule with microbubbles and delayed opacification of the LA and LV

19. 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

20. Dilated capillaries  not uniform blood flow
Venous blood passed rapidly or directly thro intrapulmonary shunt to pulmonary veins
VQ mismatch

21. 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

22. THE EnD