Hemodynamic failure and graft dysfunction after lung transplant: A possible clinical continuum with immediate and long-term consequences.

INTRODUCTION: The postoperative hemodynamic management after lung transplant (LUTX) is guided by limited evidence. We aimed to describe and evaluate risk factors and outcomes of postoperative vasoactive support of LUTX recipients. METHODS: In a single-center retrospective analysis of consecutive adult LUTX, two cohorts were identified: (1) patients needing prolonged vasoactive support (>12 h from ICU admission) (VASO+); (2) or not (VASO-). Postoperative hemodynamic characteristics were thoroughly analyzed. Risk factors and outcomes of VASO+ versus VASO- cohorts were assessed by multivariate logistic regression and propensity score matching. RESULTS: One hundred and thirty-eight patients were included (86 (62%) VASO+ versus 52 (38%) VASO-). Vasopressors (epinephrine, norepinephrine, dopamine) were used in the first postoperative days (vasoactive inotropic score at 12 h: 6 [4-12]), while inodilators (dobutamine, levosimendan) later. Length of vasoactive support was 3 [2-4] days. Independent predictors of vasoactive use were: LUTX indication different from cystic fibrosis (p = .003), higher Oto score (p = .020), longer cold ischemia time (p = .031), but not preoperative cardiac catheterization. VASO+ patients showed concomitant hemodynamic and graft impairment, with longer mechanical ventilation (p = .010), higher primary graft dysfunction (PGD) grade at 72 h (PGD grade > 0 65% vs. 31%, p = .004, OR 4.2 [1.54-11.2]), longer ICU (p < .001) and hospital stay (p = .013). Levosimendan as a second-line inodilator appeared safe. CONCLUSIONS: Vasoactive support is frequently necessary after LUTX, especially in recipients of grafts of lesser quality. Postoperative hemodynamic dysfunction requiring vasopressor support and graft dysfunction may represent a clinical continuum with immediate and long-term consequences. Further studies may elucidate if this represents a possible treatable condition.

Hyperammonemia Syndrome After Lung Transplantation: A Double-Hit Fatal Syndrome. A Case Report.

Hyperammonemia after lung transplantation is a rare but potentially fatal condition. A 59-year-old male patient affected by pulmonary fibrosis underwent an uncomplicated bilateral lung transplant. Fourteen days after the procedure, the patient developed severe encephalopathy caused by elevated serum ammonia levels. Ureaplasma parvum and Mycoplasma hominis were found on bronchial aspirate and urinary samples as well as on pharyngeal and rectal swabs. Despite the initiation of multimodal therapy, brain damage due to hyperosmolarity was so extensive to evolve into brain death. The autopsy revealed glutamine synthetase hypo-expression in the hepatic tissue. The pathophysiology of hyperammonemia syndrome in lung transplant recipients remains unclear. Previous studies have described the presence of disorders of glutamine synthetase, while others considered the infection with urea-splitting microorganisms as a cause of hyperammonemia syndrome. Our report describes the case of a patient who developed hyperammonemia after a lung transplant in which both the aforementioned etiologies were documented. A high level of clinical suspicion for hyperammonemia syndrome should be maintained in lung transplant recipients. Timely recognition and treatment are critical to prevent the potentially dreadful evolution of this severe complication.