Perioperative normovolemic anemia is safe in pediatric living-donor liver transplantation

BACKGROUND

Perioperative normovolemic anemia was applied in pediatric living-donor liver transplant (LDLT) recipients with the aim of reducing the use of blood products and decreasing transfusion-related risk.

METHODS

The anemic state was allowed to occur by replacing intraoperative blood and transudate loss with colloid solutions and a discriminate use of packed red blood cells. When blood transfusion was required, the amount of blood replacement was calculated to target a hemoglobin level not higher than 8 to 9 g/dL.

RESULTS

Forty-eight pediatric patients underwent LDLT. Their mean hemoglobin and hematocrit levels were maintained below 9 g/dL and 27%, respectively, at the end of the operation, at the time of extubation, postoperative days 3, 10, and 20, and at the time of discharge. The mean ventilatory support time was 15.7 hr, and no patient required reintubation. Graft function normalized within the first week posttransplant in all patients, and there was no documented case of acute hepatic artery thrombosis. All the patients were discharged with acceptable liver function, and 98% of them remain alive to date.

CONCLUSION

Routine application of perioperative normovolemic anemia in pediatric LDLT has allowed the sparing use of blood products. Approximately half of our patients (42%) did not require intraoperative blood transfusion; 31% of the patients went home without receiving any blood products except 5% albumin. There were no adverse effects with this maneuver, and graft function was good in all patients.

Hemodilution does not alter arterial baroreflex control of heart rate in anesthetized dogs

The cardiovascular effects of acute normovolemic hemodilution (ANH) are characterized by increased cardiac output and decreased systemic vascular resistance. However, whether arterial baroreflex function is altered by ANH remains undetermined. We assigned 23 anesthetized, mechanically ventilated dogs to mild ANH (hemoglobin, 7-8 g/dL; n = 11) or profound ANH (hemoglobin, 4-5 g/dL; n = 12) achieved by phlebotomy and simultaneous exchange with lactated Ringer's solution at 1:3 ratio to maintain constant central venous pressure and pulmonary artery occluded pressure. Baroreflex sensitivity was assessed by measurements of RR intervals of the electrocardiogram and mean arterial blood pressure (MAP) through a femoral artery catheter. Baroreflex responses were triggered by bolus IV injections of phenylephrine (25-75 micro g) and nitroprusside (50-100 micro g). The linear portion of the baroreflex curves relating RR intervals and MAP were used to determine baroreflex sensitivities. Compared with the predilution period, both ANH groups had significant increases in cardiac output and decreases in systemic vascular resistance (P < 0.01), whereas MAP and heart rate (HR) remained unchanged. However, no significant difference was detected between pre-ANH and post-ANH baroreflex sensitivities in either group. Our results indicate that arterial baroreflex control of HR is preserved during ANH to a hemoglobin concentration of 4-5 g/dL in anesthetized dogs.

IMPLICATIONS

Acute normovolemic hemodilution may be preoperatively used to minimize the requirement of allogeneic blood products during major surgery. We found that baroreflex function is preserved during mild (hemoglobin concentration, 7-8 g/dL) and profound hemodilution (hemoglobin concentration, 4-5 g/dL) in pentobarbital-anesthetized dogs.