Perioperative perfusion strategies for optimal fluid management in liver transplant recipients with renal insufficiency

Renal support during liver transplantation: when to consider it?

Patients undergoing orthotopic liver transplantation constitute a difficult-to-treat population. They often have multiorgan dysfunction: acute kidney injury, severe water-electrolyte and acid-base imbalances, systemic inflammatory responses, thrombocytopenia, as well as abnormalities of coagulation and fibrinolysis. All of these disorders may be further exacerbated by the surgical procedure, which is lengthy and technically complex, requiring massive blood product and other fluid infusions with a high risk to develop severe lactic acidosis, hyperkalemia, or cerebral edema. These considerations provide a rationale to institute intraoperative renal replacement therapy (ioRRT), at least for the most critically ill, namely, patients with kidney dysfunction, or those in whom one anticipates intraoperative clinical and technical problems. This article discusses the most common indications and strategies for ioRRT, examining their advantages and disadvantages as well as current experiences.

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.

Risk factors for acute renal failure: inherent and modifiable risks

PURPOSE OF REVIEW

Our purpose is to discuss established risk factors in the development of acute renal failure and briefly overview clinical markers and preventive measures.

RECENT FINDINGS

Findings from the literature support the role of older age, diabetes, underlying renal insufficiency, and heart failure as predisposing factors for acute renal failure. Diabetics with baseline renal insufficiency represent the highest risk subgroup. An association between sepsis, hypovolemia, and acute renal failure is clear. Liver failure, rhabdomyolysis, and open-heart surgery (especially valve replacement) are clinical conditions potentially leading to acute renal failure. Increasing evidence shows that intraabdominal hypertension may contribute to the development of acute renal failure. Radiocontrast and antimicrobial agents are the most common causes of nephrotoxic acute renal failure. In terms of prevention, avoiding nephrotoxins when possible is certainly desirable; fluid therapy is an effective prevention measure in certain clinical circumstances. Supporting cardiac output, mean arterial pressure, and renal perfusion pressure are indicated to reduce the risk for acute renal failure. Nonionic, isoosmolar intravenous contrast should be used in high-risk patients. Although urine output and serum creatinine lack sensitivity and specificity in acute renal failure, they remain the most used parameters in clinical practice.

SUMMARY

There are identified risk factors of acute renal failure. Because acute renal failure is associated with a worsening outcome, particularly if occurring in critical illness and if severe enough to require renal replacement therapy, preventive measures should be part of appropriate management.