A Multicenter evaluation of safety of early extubation in liver transplant recipients

Small single-institutional studies performed prior to the introduction of organ allocation using the Model for End-Stage Liver Disease (MELD) suggest that early airway extubation of liver transplant recipients is a safe practice. We designed a multicenter study to examine adverse events associated with early extubation in patients selected for liver transplantation using MELD score. A total of 7 institutions extubated all patients meeting study criteria and reported adverse events that occurred within 72 hours following surgery. Adverse events were uncommon: occurring in only 7.7% of 391 patients studied. Most adverse events were pulmonary or surgically related. Pulmonary complications were usually minor, requiring only an increase in ambient oxygen concentration. The majority of surgical adverse events required additional surgery. Analysis of a limited set of perioperative variables suggest that blood transfusions and technical factors were associated with an increased risk of adverse events. In conclusion, while early extubation appears to be safe under specified circumstances, there are performance differences between institutions that remain to be explained

A Randomized Clinical Trial Testing the Anti-Inflammatory Effects of Preemptive Inhaled Nitric Oxide in Human Liver Transplantation

<div><p>Decreases in endothelial nitric oxide synthase derived nitric oxide (NO) production during liver transplantation promotes injury. We hypothesized that preemptive inhaled NO (iNO) would improve allograft function (primary) and reduce complications post-transplantation (secondary). Patients at two university centers (Center A and B) were randomized to receive placebo (n = 20/center) or iNO (80 ppm, n = 20/center) during the operative phase of liver transplantation. Data were analyzed at set intervals for up to 9-months post-transplantation and compared between groups. Patient characteristics and outcomes were examined with the Mann-Whitney U test, Student t-test, logistic regression, repeated measures ANOVA, and Cox proportional hazards models. Combined and site stratified analyses were performed. MELD scores were significantly higher at Center B (22.5 vs. 19.5, p<0.0001), surgical times were greater at Center B (7.7 vs. 4.5 hrs, p<0.001) and warm ischemia times were greater at Center B (95.4 vs. 69.7 min, p<0.0001). No adverse metabolic or hematologic effects from iNO occurred. iNO enhanced allograft function indexed by liver function tests (Center B, p<0.05; and p<0.03 for ALT with center data combined) and reduced complications at 9-months (Center A and B, p = 0.0062, OR = 0.15, 95% CI (0.04, 0.59)). ICU (p = 0.47) and hospital length of stay (p = 0.49) were not decreased. iNO increased concentrations of nitrate (p<0.001), nitrite (p<0.001) and nitrosylhemoglobin (p<0.001), with nitrite being postulated as a protective mechanism. Mean costs of iNO were $1,020 per transplant. iNO was safe and improved allograft function at one center and trended toward improving allograft function at the other. ClinicalTrials.gov with registry number 00582010 and the following URL:<a href="http://clinicaltrials.gov/show/NCT00582010" target="_blank">http://clinicaltrials.gov/show/NCT00582010</a>.</p></div

Patient and Surgery Demographics for Center A Cohort.

<p>Values show median (range). P-values calculated from unpaired t-test for placebo vs. iNO. N = 20 except An = 19. Bn = 18.</p

Effects of iNO on liver nitrite levels pre- (LB1) and post-reperfusion (LB2).

<p>Nitrite was measured in paired liver biopsies and data normalized to protein. No significant differences in nitrite levels were observed pre- vs. post-reperfusion or between placebo and iNO treatments.</p

Changes in metHb and nitrogen dioxide (NO₂) as a function of blood draw (BD) in placebo (○) or iNO (▪) groups.

<p>Data are mean ± SEM (n = 20 for each group, except UAB placebo where n = 19 and UW iNO where n = 17–20. *P<0.0001 by 2-way ANOVA with Bonferroni multiple comparisons post-test.</p

Individual responses to iNO on TUNEL staining pre- and post-reperfusion.

<p>Panel A and B show changes in TUNEL positive nuclei in hepatic central vein area and panels C and D in the hepatic triad area for Center A (panel A and B) and Center B (panel C and D) cohorts. Indicated P-values determined by Wilcoxon rank-sum (n = 18–20).</p

iNO effects on plasma ceruloplasmin activity.

<p>Plasma ceruloplasmin activity was measured in venous samples collected during surgery from patients administered placebo (□) or iNO (•). Data show mean ± SEM (n = 19–20).</p

Patient demographic differences between study sites.

<p>Panels A–E show respectively patient weight, MELD scores, surgery, warm ischemic times and donor risk index (DRI). Each data point represents individual patient (n = 37–40 for Center A, and n = 40 for Center B). Indicated P-values are from unpaired t-test (panel A and E) or Mann-Whitney U test (panels B–D).</p

The Distribution, Frequency and Type of Hepatobiliary Complications.

<p>Center A.</p><p>Placebo: allograft dysfunction (1), primary graft non-function (1), reduced portal vein flow (1), hepatic artery bleeding (2).</p><p>iNO: allograft dysfunction (1), hepatic artery bleeding (1).</p><p>Center B.</p><p>Placebo: 1-month:primary graft dysfunction (1), reduced hepatic artery blood flow (1), biliary leak (1), 6-months:biliary stricture (2), 9-months:rejection (1), hepatic artery stenosis (1), death (1).</p><p>iNO: 9-months:hepatic artery stenosis (1), death (1).</p