Effect of iron metabolism of preoperation on the length of intensive care unit stay in liver transplant recipients

Objective To evaluate the effect of iron metabolism of preoperation on the length of intensive care unit (ICU) stay in liver transplant recipients. Methods A retrospective study was conducted. 120 adult liver transplant recipients admitted to Tianjin First Central Hospital from September 2015 to September 2017 were enrolled. The basic data, model of end-stage liver disease (MELD) evaluation system score at admission; iron metabolism index, routine blood test, blood biochemistry, coagulation time and C-reactive protein (CRP) level within 24 hours after admission; intraoperative clinical indicators such as operation time, operation bleeding volume, red blood cells and fresh frozen plasma input volume, hot ischemia time, cold ischemia time, urine volume; and the length of ICU stay were collected. All patients were divided into iron deficiency group (ID group; serum ferritin 300 μg/L, or serum ferritin 100-300 μg/L and transferrin saturation > 0.20) according iron deficiency standard. The indexes of iron metabolism, basic data and clinical indicators of two groups were compared. The correlation between serum ferritin level and the length of ICU stay was analyzed by Pearson correlation. Results Compared with non-ID group, the levels of serum iron concentration and serum ferritin were significantly decreased in ID group [serum iron concentration (μmol/L): 3.50±1.62 vs. 14.50±2.31, serum ferritin (μg/L): 67.00±31.54 vs. 315.00±36.73, both P < 0.01], infusion volume of intraoperative red blood cells and fresh frozen plasma were significantly increased, and the length of ICU stay was significantly prolonged (days: 6.5±2.4 vs. 3.3±0.5, P < 0.01). There was no significant difference in transferrin saturation, CRP and other clinical indicators between the two groups. Correlation analysis showed that serum ferritin level was negative correlated with the length of ICU stay (r = -0.768, P < 0.001). Conclusion Preoperative iron deficiency in liver transplant recipients will lead to increased blood transfusion and prolonged length of ICU stays. Key words: Intensive care unit; Liver transplantation; Ferritin; Transferrin saturation; The length of hospital stay