Derivation of a risk index for the prediction of massive blood transfusion in liver transplantation

Anesthetic management of hepatic transplantation

PURPOSE OF REVIEW

The present review describes new trends and ongoing controversies in the anesthetic care of liver transplant recipients.

RECENT FINDINGS

Recent studies have improved our knowledge of conditions increasing perioperative risk, such as portopulmonary hypertension and renal failure. Improved surgical and anesthetic management has reduced intraoperative blood loss, as more studies identify an independent association between blood transfusion and poor outcome. New concepts in the coagulopathy of liver failure are emerging, with clear implications for clinical practice, including greater awareness of the risks of intraoperative thromboembolism. Less invasive intraoperative hemodynamic monitoring has been advocated, as has wider use of transoesophageal echocardiography. Early extubation is becoming more routinized.

SUMMARY

Anesthetic management still varies widely between liver transplant centers with little data to indicate best practice. Future research should focus on fluid replacement, prevention and treatment of coagulopathy, care of the acutely ill patient and the safety and benefits of early extubation.

Elderly donors for HCV(+) versus non-HCV recipients: patient survival following liver transplantation

INTRODUCTION

Chronic liver failure due to hepatitis C virus (HCV)-related cirrhosis is the leading indication for liver transplantation. Inferior long-term results have been reported for liver transplantation in HCV(+) patients, especially when marginal donor livers are utilized.

AIM

The aim of this study was to analyze retrospectively the outcome of liver transplantation patients from elderly donors in the case of HCV(+) versus non-HCV recipients.

METHODS

Among 330 liver transplantations performed from January 1994 to December 2006, we selected 244 excluding acute hepatic failure, children, and retransplants. Among these patients we analyzed 232 subjects who underwent the piggyback technique. Donor risk index (DRI) as described by Feng et al was applied using 1.7 as a cutoff value. We used Kaplan-Meier survival and Cox hazard regression analyses. We studied 14 donor variables using descriptive statistical tests.

RESULTS

There were 148 (63.8%) HCV(+) recipients and 84 (36.2%) non-HCV liver transplant recipients. Among HCV(+) recipients, 130/148 (87.8%) patients received livers, from donors less than 50 years old, and 18/148 (12.2%), over 50 years. The descriptive statistics of patient categorical variables are shown in Table 1, and continuous variables in Table 2. The cumulative proportional survival curves are shown in Figs 1 and 2. Mortality predictive factors in HCV(+) liver transplant recipients with donor age > 50 years old as determined by Cox hazard regression showed that death risk was increased with hazard ratios for warm ischemia = 1.01 (P = .001); for red blood cell intraoperative requirements = 2.63 (P = .003); for Child-Turcotte-Pugh classification points = 2.25 (P = .04), and for DRI > 1.7 = 2.19 (P = .03). In conclusion, advancing donor age, as well as the use of nonideal donors, intraoperative bleeding, and prolonged warm ischemia, had an adverse influence on patient survival for HCV(+) recipients.

Intraoperative massive transfusion decreases survival after liver transplantation

Patients undergoing liver transplantation often experience coagulopathy and massive intraoperative blood loss that can lead to morbidity and reduced survival. The aim of this study was to verify the survival rate and discover predictive factors for death among liver transplant patients who received massive intraoperative blood transfusions. This cohort study was based on prospective data collected retrospectively from January 2004 to July 2006. The 232 patients were distributed according to their blood requirements, (namely, more or less than 6 units), including red blood cell saver. The statistical analyses were performed using Student t test, Cox hazard regression, and the Kaplan-Meier method (log-rank test). The massively transfused cohort displayed higher Child-Pugh classifications (10.2 vs 9.6; P = .03); model for end-stage liver disease (MELD) scores (19 vs 17; P = .02); recipient weights (75.4 vs 71 kg; P = .03); as well as warm ischemia times (70.7 vs 56.4 minutes; P < .001) and surgery times (584.6 vs 503.4 minutes; P < .05). The proportional hazard (Cox) regression analysis showed that the risk of death increased 2.1% for each unit of donor sodium and 1.6% for each additional year of donors age over 50. The survival rates at 6, 12, 60, and 120 months for > or = 6 vs <6 U of blood transfusion of 63.8% vs 83.3%; 53.9% vs 76.3%; 40% vs 60%; 34.5% vs 49.2%. In conclusion, we observed that patients receiving over 6 red blood cell units intraoperatively displayed reduced survival. Predictive factors for this risk factor were high donor level of sodium and of age.

A predictive model for massive transfusion in combat casualty patients

BACKGROUND

Massive transfusion (MT) is associated with increased morbidity and mortality in severely injured patients. Early and aggressive use of blood products in these patients may correct coagulopathy, control bleeding, and improve outcomes. However, rapid identification of patients at risk for MT has been difficult. We postulated that evaluation of clinical variables routinely assessed upon admission would allow identification of these patients for earlier, more effective intervention.

METHODS

A retrospective cohort study was conducted at a single combat support hospital to identify risk factors for MT in patients with traumatic injuries. Demographic, diagnostic, and laboratory variables obtained upon admission were evaluated. Univariate and multivariate analyses were performed. An algorithm was formulated, validated with an independent dataset and a simple scoring system was devised.

RESULTS

Three thousand four hundred forty-two patient records were reviewed. At least one unit of blood was transfused to 680 patients at the combat support hospital. Exclusion criteria included age less than 18 years, transfer from another medical facility, designation as a security internee, or incomplete data fields. The final number of patients was 302, of whom 26.5% (80 of 302) received a MT. Patients with MT had higher mortality (29 vs. 7% [p < 0.001]), and an increased Injury Severity Score (25 +/- 11.1 vs. 18 +/- 16.2 [p < 0.001]). Four independent risk factors for MT were identified: heart rate >105 bpm, systolic blood pressure <110 mm Hg, pH <7.25, and hematocrit <32.0%. An algorithm was created to analyze the risk of MT (area under the curve [AUC] = 0.839). In an independent data set of 396 patients the ability to accurately identify those requiring MT was 66% (AUC = 0.747).

CONCLUSIONS

Independent predictors for MT were identified in a cohort of severely injured patients requiring transfusions. Patients requiring a MT can be identified with variables commonly obtained upon hospital admission.