Effect of low central venous pressure and phlebotomy on blood product transfusion requirements during liver transplantations

Bleeding in liver surgery: prevention and treatment

Intraoperative blood loss and transfusion of blood products are negatively associated with postoperative outcome after liver surgery. Blood loss can be minimized by surgical methods, including vascular clamping techniques, the use of dissection devices, and the use of topical hemostatic agents. Preoperative correction of coagulation tests with blood products has not been shown to reduce intraoperative bleeding and it may, in fact, enhance the bleeding risk. Maintaining a low central venous pressure has been shown to be effective in reducing blood loss during partial liver resections, and volume contraction rather than prophylactic transfusion blood products seems justified in patients undergoing major liver surgery. Although antifibrinolytic drugs have proved to be effective in reducing blood loss during liver transplantation, systemic hemostatic drugs are of limited value in reducing blood loss in patients undergoing partial liver resections.

Renal dysfunction in the perioperative liver transplant period

PURPOSE OF REVIEW

Acute kidney failure in the perioperative liver transplant recipients results in an increased hospital length of stay, acute rejection, infection rate and overall mortality. Thus, it is of great importance to be able to recognize, prevent and treat kidney injury.

RECENT FINDINGS

Immediate post liver transplant kidney dysfunction is increased in those with pretransplant kidney failure, hepato-renal syndrome, intraoperative hypotension, intraoperative hypovolemia, aprotinin use and those requiring transfusion of more units of blood products or needing to return to the operating room.

SUMMARY

To date, avoiding risky clinical situations, maintaining homeostasis and a multidisciplinary approach to care have been reasonable approaches to decrease the incidence of postoperative acute kidney injury.

Changing trends in transfusion practice in liver transplantation

PURPOSE OF REVIEW

Prevention of excessive blood loss is an important issue in the perioperative management of liver transplantation. This review describes changing trends in blood products use, risk predicting of blood transfusion, variability in use and practices, as well as transfusion safety during liver transplantation.

RECENT FINDINGS

Over the last 20 years, the average use of blood products per case has considerably decreased. There are marked interinstitutional differences in blood use. Differences in patient population characteristics and surgical techniques are a partial explanation, but differences in transfusion practices probably account for a substantial part of the variability. Recent data have sparked off ongoing controversy relating to volume replacement therapy and its impact on blood loss. New studies emphasize the risks associated with transfusion in liver transplantation.

SUMMARY

Recent studies call for continuing every reasonable effort to minimize the use of blood components and can guide us in new approaches to this vital problem.

The impact of intraoperative transfusion of platelets and red blood cells on survival after liver transplantation

BACKGROUND

Intraoperative transfusion of red blood cells (RBC) is associated with adverse outcome after orthotopic liver transplantation (OLT). Although experimental studies have shown that platelets contribute to reperfusion injury of the liver, the influence of allogeneic platelet transfusion on outcome has not been studied in detail. In this study, we evaluate the impact of various blood products on outcome after OLT.

METHODS

Twenty-nine variables, including blood product transfusions, were studied in relation to outcome in 433 adult patients undergoing a first OLT between 1989 and 2004. Data were analyzed using uni- and multivariate stepwise Cox's proportional hazards analyses, as well as propensity score-adjusted analyses for platelet transfusion to control for selection bias in the use of blood products.

RESULTS

The proportion of patients receiving transfusion of any blood component decreased from 100% in the period 1989-1996 to 74% in the period 1997-2004. In uni- and multivariate analyses, the indication for transplantation, transfusion of platelets and RBC were highly dominant in predicting 1-yr patient survival. These risk factors were independent from well-accepted indices of disease, such as the Model for End-Stage Liver Disease score and Karnofsky score. The effect on 1-yr survival was dose-related with a hazard ratio of 1.377 per unit of platelets (P = 0.01) and 1.057 per unit of RBC (P = 0.001). The negative impact of platelet transfusion on survival was confirmed by propensity-adjusted analysis.

CONCLUSION

This retrospective study indicates that, in addition to RBC, platelet transfusions are an independent risk factor for survival after OLT. These findings have important implications for transfusion practice in liver transplant recipients.

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.

The development of perioperative practices for liver transplantation: advances and current trends

Transplantation is a young medical specialty that has grown rapidly over the past 50 years. Anesthesiologists, surgeons and hepatologists are all essential partners in the process of determining patient outcome. Each specialty has made landmark improvements in patient outcome. However, there is still variability in practice patterns in each of the 3 major specialties. This review will use a historic perspective to explore the unique forces that shaped specific transplant practices and those that gave rise to differences in perioperative practices. Anesthesiologists and surgeons have made significant improvements in the management of blood loss, and coagulation monitoring and intervention. This has improved operative survival and early patient outcome. Perioperative survival has improved despite a worldwide shortage of donor organs and a trend to transplant sicker patients. A smaller pool of donor organs is required to meet the needs of an expanding waiting list. The innovations to reduce deaths on the transplant wait list are reviewed along with their impact on overall patient outcome. The evolving organ shortage is the pinnacle point in shaping future transplant practices. Currently, institutional-specific practices may be reinforced by the informal "tutorship" that is used to train physicians and by the resources available at each site of practice. However, there is evidence that specific intraoperative practices such as the use of a low central venous pressure, selection of vasopressors and certain surgical techniques can modify patient outcome. Further investigation is needed to determine whether the good or the bad associated with each practice prevails and in what unique circumstance.

Effect of restrictive fluid management and acute normovolemic intraoperative hemodilution on transfusion requirements during living donor hepatectomy

The aim of this study was to evaluate the safety and effectiveness of a restrictive fluid management strategy and acute normovolemic intraoperative hemodilution (ANIH) to decrease transfusion requirements among living-donors for liver transplantation (LDLT). We retrospectively reviewed the data of 114 consecutive LDLT donors. The patients were divided into 2 groups based on whether (Group I; n = 73) or not (Group II; n = 41) a restrictive fluid management strategy with ANIH was used during the procedure. For each group we recorded demographic features, intraoperative and postoperative transfusions, amount of administered intraoperative crystalloid and colloids, intraoperative hemodynamics, preoperative and postoperative laboratory values (renal and liver functions), intraoperative and postoperative urine output, and length of hospital stay. Demographic features and preoperative laboratory values were similar for the 2 groups, except for age (Group I, 36 +/- 9 vs Group II, 33 +/- 8; P = .04). Intraoperatively, 7 patients (10%) in Group 1 and 9 (22%) in Group II required blood transfusions (P = .06). The respective amount of heterologous blood transfusion for Groups I and II was 96 +/- 321 mL vs 295 +/- 678 mL (P = .06). Postoperative renal and liver functions were not different between the 2 groups (P > .05). Patients in Group I had a shorter hospital stay than those in Group II (8.2 +/- 4.6 days vs 10.1 +/- 4.9 days; P = .03). In conclusion, a restrictive fluid management strategy with ANIH was a safe blood-salvage technique for LDLT. This approach was also associated with decreased length of hospital stay and a trend toward decreased transfusion requirements.

Liver transplantation in Jehovah's Witness patients in Australasia

Until recently, liver transplantation was contraindicated in Jehovah's Witness patients because of recipient-imposed restrictions on use of blood products. However, recent improvements in surgical and anaesthetic techniques and new procoagulant agents challenge this practice. We describe two Jehovah's Witness patients who had successful liver transplantation without blood transfusion. To our knowledge, these are the first such cases in Australasia. The techniques used to minimise blood loss and transfusion requirements could potentially benefit all patients undergoing major surgery.

Hemodynamics During Liver Transplantation

Assessing the optimal volemia in the perioperative course of liver transplantation is a challenge for the anesthesiologist. Traditional estimates of intravascular volume status, such as pulmonary artery occlusion pressure (PAOP), have been widely shown to poorly correlate with changes in cardiac output among critically ill patients. Hence, there has been recent interest in alternative, catheter-related, bedside device volume estimates using thermodilution. Continuous end diastolic volume (CEDVI) showed better correlations with cardiac performance than cardiac filling pressures in studies performed in critically ill patients. When compared with conventional pressure-derived data, preload monitoring estimated as intrathoracic blood volume index (ITBVI) with the PiCCO system based on an integrated transpulmonary thermodilution technique better reflected left ventricular filling both in critically ill patients and those who underwent liver transplantation. Moreover, in liver transplantation, the use of transoesophageal echocardiography (TEE) has been increasing for it provides rapid visualization of the dimension and function of heart chambers as well as the left ventricular end diastolic area index (EDAI) that seem to correlate with graded acute hypovolemia, although its validity as on preload index is still under discussion.

Evaluation of cell salvage autotransfusion utility during liver transplantation

BACKGROUND

Orthotopic liver transplantation (OLT) may be associated with massive blood loss and the need for allogenic blood product transfusions. Cell salvage autotransfusion (CS) is an attractive alternative to allogenic red blood cell (RBC) transfusion. However, controversy surrounds its usefulness during OLT; some studies stated that CS decreased transfusions of allogenic blood products and others stated that blood loss was increased. The aim of this study was to evaluate the efficiency of the CS during OLT.

PATIENTS AND METHODS

After approval by the institutional ethics committee, a prospective survey was undertaken. A total of 150 consecutive OLTs were included in the study. Two groups of patients were formed. Period 1 included patients 1-75 with no CS use. Period 2 comprised patients 76-150 with systematic CS use.

RESULTS

Patients from both periods were comparable. CS was used in all cases in period 2, and there was enough salvaged blood to retransfuse 65% of these OLTs. The mean volume of retransfused blood was 338+/-339 ml. The transfusion rate did not change from period 1 to period 2. The mean number of RBC units transfused per patient was 0.4+/-0.9 vs 0.4+/-1.2 with 78.7% vs 81.3% of cases not receiving transfusion of any blood product. The threshold for RBC transfusions was the same. The length of surgery and blood loss were greater in period 2 than in period 1 (associated with the arrival of two junior surgeons), but the hemoglobin (Hb) value was also higher at the end of surgery (93.8+/-19.3 g/L vs 85.2+/-17.8 g/L, p<0.0001).

CONCLUSION

Despite increased blood loss in period 2, CS saved 21 g/L of Hb per patient or two RBC unit transfusions. As long as we cannot predict with accuracy which patients will bleed, we will continue to use the CS for all OLTs.

A comparison of intrathecal morphine/fentanyl and patient-controlled analgesia with patient-controlled analgesia alone for analgesia after liver resection

Continuous epidural anesthesia and analgesia may be considered in liver resection, but is often avoided because of the potential development of coagulopathies and the risk of epidural hematoma. In this prospective, randomized, double-blind study we compared postoperative morphine consumption via patient-controlled analgesia after liver surgery between two groups of patients: patients receiving a preoperative dose of intrathecal morphine (0.5 mg) and fentanyl (15 microg) (treatment group) and patients receiving a sham intrathecal injection (placebo group). Forty patients scheduled for major liver resection (> or = two segments) were enrolled. The primary outcome measure was patient-controlled analgesia morphine consumption. Secondary outcomes were evaluation of pain at rest and with movement, scored on a visual analog scale with assessment of sedation, nausea, pruritus, and respiratory frequency. Outcome measures were recorded at 6, 12, 18, 24, and 48 h postspinal anesthesia or simulation. Patients in the placebo group consumed approximately three times more morphine during each time interval than patients in the treatment group (at 48 h: 124 +/- 30 vs 47 +/- 21 mg, P < 0.0001). Pain evaluation on the visual analog scale was lower for the first 18 h in the treatment group. There was no difference in the incidence of side effects in both groups. Intrathecal morphine (0.5 mg) and fentanyl (15 microg) given before liver surgery significantly decreased postoperative morphine consumption compared to placebo without any increase in side effects.