Intraoperative changes in hyponatremia as a risk factor for prolonged mechanical ventilation after living donor liver transplantation

Prolonged mechanical ventilation (PMV), a common clinical manifestation, may result in fatal outcomes after living donor liver transplantation (LDLT). Although hyponatremia contributes to neurologic alterations in association with PMV, the effects of acute changes in hyponatremia during LDLT have not been well studied. We sought to determine whether an acute change in hyponatremia during surgery might be a risk factor for PMV after LDLT. Perioperative data were retrospectively collected from 381 patients who underwent LDLT from January 2000 to December 2008. PMV was defined as the need for ≥24 hours of mechanical ventilation within the first postoperative week. Using multivariate logistic regression a simple comparison of perioperative variables between the PMV group and the non-PMV group yielded a predictive model to establish PMV. Thirty-seven patients (9.7%) experienced PMV after LDLT. Intraoperative changes in blood sodium were associated with postoperative PMV; however, the relationship was limited to patients with preoperative hyponatremia. Patients with PMV showed lower survival rates than those without PMV (56.3% vs 86.3%; P <.001). A multivariate analysis revealed that preoperative hepatic encephalopathy, hypotension during surgery (more than 3 bowls), and intraoperative changes in hyponatremia were predictive of PMV. Among the hyponatremia change subgroups, only a severe intraoperative change (≥10 mEq/L) was associated with PMV occurrence (odds ratio, 5.85; 95% confidence interval, 1.62 to 21.20, P = .007). In conclusion, a severe intraoperative change in hyponatremia was a risk factor for PMV in the immediate period after LDLT.