title: Defining and characterizing severe hypoxemia after liver transplantation in hepatopulmonary syndrome.
abstract: Hepatopulmonary syndrome is defined as a triad of liver disease, intrapulmonary vascular dilatations, and abnormal gas exchange, and it carries a poor prognosis. Liver transplantation is the only known cure for this syndrome. Severe hypoxemia in the early postoperative period has been reported to be a major complication and often leads to death in this population, but it has been poorly characterized. We sought to propose an objective definition for this complication and to describe its risk factors, incidence, and outcomes. We performed a systematic literature search and reviewed our single-center experience to characterize this complication. On the basis of the most commonly applied definition in 27 identified studies, we objectively defined severe postoperative hypoxemia as hypoxemia requiring a 100% fraction of inhaled oxygen to maintain a saturation ≥ 85% and out of proportion to any concurrent lung process. Nineteen of the 27 reports (70%) fulfilled this definition, as did 4 of the 21 patients (19%) at our center. We determined the prevalence and mortality of this complication from reports including 10 or more consecutive patients and providing sufficient postoperative details to determine whether this complication had occurred. In these reports, the prevalence of this complication was 12% (25/209). For the 11 cases with reported outcomes, the posttransplant mortality rate was 45% (5/11). There was a trend toward an increased risk of developing this complication in patients with very severe preoperative hypoxemia, defined as a partial pressure of arterial oxygen ≤ 50 mm Hg (8/41 with very severe hypoxemia versus 3/49 without severe hypoxemia, P = 0.053), and there was a significantly increased risk for patients with anatomic shunting ≥ 20% (7/25 with anatomic shunting ≥ 20% versus 1/25 without anatomic shunting ≥ 20%, P = 0.049). In conclusion, increased preoperative vigilance for this common complication is required among high-risk patients, and further research is required to identify the best management strategies.
authors.affiliation: Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, Toronto, Canada.
authors.forename: Dhruv
authors.initials: D
authors.lastname: Nayyar
authors.forename: H S Jeffrey
authors.initials: HS
authors.lastname: Man
authors.forename: John
authors.initials: J
authors.lastname: Granton
authors.forename: Samir
authors.initials: S
authors.lastname: Gupta
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000737:chemistry; D005260:Female; D020065:Hepatopulmonary Syndrome / Q000401:mortality / Q000473:pathology* / Q000628:therapy*; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D017093:Liver Failure; D016031:Liver Transplantation / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000737:chemistry; D010313:Partial Pressure; D011184:Postoperative Period; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen