Persistent Hypoxia Post Op

Persistent post-op Persistent post-op hypoxia hypoxia

ICU, Pamela Youde Nethersole Eastern HospitalDr Emily Cheung & Dr Arthur CW Lau

24 Sep 2010

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CaseCaseM/69, ADLIEx smoker, drinkerPMH:

◦eAg negative chronic hep B◦Ulcerative colitis on mesalazine◦HT

Newly diagnosed HCC over right lobe

‘C’ adm for open right hemi-hepatectomy

Uneventful operationIntra-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

CT – lung windowCT – lung window

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 takingComplaints of discomfort on

sitting up while watching TV, feels better if lying down

Symptoms present for 2 yearsP/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 beatDdx:

◦ 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

ProgressProgressInpatient 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 shuntPatient refused TEE

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Impression of the causes of hypoxemia1. Hepatopulmonary syndrome,

and2. Atelectasis due to bowel

distension

Hepatopulmonary Hepatopulmonary syndromesyndromeCharacterized 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 featuresClinical features18% 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

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PathobiologyPathobiologyGross dilatation of the

pulomonary precapillary and capillary vessels

Absolute increase in no of dilated vessels

Pleural and pulmonary AV communications and portopulomonary venous anastomoses

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Dilated capillaries not uniform blood flow

Venous blood passed rapidly or directly thro intrapulmonaryshunt to pulmonary veins

VQ mismatch

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TreatmentTreatmentNo effective medical therapiesLiver transplantation is the only

successful treatment◦pO2 < 60 mmHg is considered to be

an indication for liver transplantationLong term oxygen therapy

◦For symptomatic patients with severe hypoxaemia

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THE ENDTHE END

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