Intrauterine Intravascular Transfusion Research Articles

Pulsed Doppler flow-velocity waveforms before and after intrauterine intravascular transfusion for severe erythroblastosis fetalis

Pulsed Doppler flow-velocity waveforms before and after intrauterine intravascular transfusion for severe erythroblastosis fetalis

Prevention of Rh isoimmunization and treatment of the compromised fetus.

Intrauterine intravascular transfusion for the treatment of severe erythroblastosis fetalis has resulted in a number of benefits: (a) Direct access to the fetal vasculature allows an accurate assessment and prompt correction of anemia, albeit temporary. In contrast, intraperitoneally transfused blood may be absorbed erratically, especially in the face of ascites. (b) Intravascular treatments can be performed, in general, as early as 17 weeks of gestation, earlier than intraperitoneal approaches permit. (c) Reversal of hydrops along with the correction of anemia and hypoproteinemia has significantly reduced neonatal morbidity and mortality. None of the surviving neonates in our series required either thoracentesis or paracentesis following delivery, and 40% did not require neonatal exchange transfusion. (d) Treatments may be safely performed until pulmonic maturity has been established and/or an EFW of greater than 2,000 g has been reached, reducing problems of prematurity. (e) Central vein and umbilical vein hypertension may be arrested or prevented, thereby allowing fetal liver function to return to normal. While isoimmunization stands as a disease that has been quite successfully reduced in frequency and severity by the careful attention and treatment by obstetricians, cases still occur. Due to the reduced frequency of severe disease, fewer physicians are trained and experienced in performing this difficult procedure. As fewer transfusions are required, the value of regionalized treatment centers will have to be considered carefully, in order to maximize the experience and efficiency of the intravascular intrauterine transfusion treatment teams.

Management of isoimmunized pregnancy by use of intravascular techniques

Twenty-two patients who had 23 pregnancies complicated by isoimmunization were managed by the use of intravascular methods on an outpatient basis. Nine patients underwent 30 percutaneous fetal blood sampling procedures to determine fetal blood type or hematocrit, without complication. Thirteen patients underwent 45 intrauterine fetal transfusions via the umbilical vessels and 16 intraperitoneal fetal transfusions. The overall survival rate in this series was 85.7%. Survival among fetuses that were hydropic at initial evaluation was 83.3%. The procedure-related perinatal mortality rate for intravascular intrauterine transfusions was 2.2%. Knowledge of fetal blood type and hematocrit allowed treatment individualized to the specific needs of each patient. In particular, the ability to transfuse blood directly into the vascular system of the hydropic fetus proved to be lifesaving in those patients.

The reversal of hydrops fetalis by intravascular intrauterine transfusion in severe isoimmune fetal anemia

Seventy-two intrauterine intravascular transfusions were performed on 26 patients with severe erythroblastosis fetalis. Twenty of the 26 fetuses were hydropic at the time of referral. Of the 20 hydropic fetuses, 16 (80%) survived. Hydrops was completely reversed in 13 of the 16 fetuses (81%). Total protein of <3 gm/dl, albumin <2 gm/dl, and a hematocrit level of <15% were associated with hydrops fetalis. After hydrops was reversed, total protein 3 gm/dl, albumin 2 gm/dl, along with a sustained hematocrit level of 15%, were found. Only three neonates were born with minimal ascites, two of whom had had intraperitoneal transfusions before intravascular treatments. There were 21 survivors of the total group, giving an overall survival rate of 82%. There was one neonatal death from severe respiratory distress syndrome. Thirty-eight percent of the neonates did not require exchange transfusions in the newborn period. Intrauterine intravascular transfusions appear to be an effective mode of therapy in severe erythroblastosis fetalis and not only increase survival rates but also decrease neonatal morbidity and mortality.

Pulsed Doppler flow-velocity waveforms before and after intrauterine intravascular transfusion for severe erythroblastosis fetalis

Pulsed Doppler studies of the fetal and maternal circulations were carried out before and after 64 intrauterine transfusions performed on 24 fetuses. A model was derived for the prediction of hematocrit before the first transfusion: Hematocrit = 7.778 − (0.088 × peak velocity in descending aorta) + (0.968 × gestational age [weeks]) − (10.911 if hydrops present) (r = 0.876, p < 0.0001). An alternative formula, excluding hydrops, was slightly less predictive: Hematocrit = 45.312 − (56.261 × umbilical cord Pourcelot index) − (0.128 × peak velocity in descending aorta) + (1.042 × gestational age) (r = 0.822, p < 0.001). Neither model was accurate in the prediction of hematocrit before second or subsequent transfusion. A third model was derived from second-transfusion data: Hematocrit = 40.524 − (0.045 × peak velocity in descending aorta) − (10.693 × pulsatility index of maternal uterine artery) (r = 0.81, p < 0.003). However, this model was unable to predict hematocrit before third or later transfusions. No changes in Doppler parameters before and after transfusion were found. We conclude that pulsed Doppler ultrasound may be helpful in the evaluation of isoimmunized pregnancies, in differentiating anemic from normal fetuses. It does not appear to be useful in determining the timing of later transfusions. The lack of change before and after transfusions suggests that these vessels will not provide significant information concerning the effect of rapid volume and hematocrit changes in the fetus.

Fetal abnormalities: diagnosis or treatment with percutaneous umbilical blood sampling under continuous US guidance.

Percutaneous umbilical blood sampling has become an important tool in maternal-fetal medicine and allows direct access to fetal blood. In 52 patients, 100 successful consecutive blood sampling procedures were done for a variety of indications, including 20 intravascular intrauterine fetal transfusions for isoimmune disease. Indications, technique, and complications in this series of percutaneous umbilical blood sampling procedures are described.

Technical aspects of intravascular intrauterine transfusions: Lessons learned from thirty-three procedures

Our technique for performing intravascular transfusions is described and four failed attempts are presented. The appropriate choice of needle, insertion site, and premedication are discussed. A rationale for intravenous fetal muscle blockade in selected cases is presented and a transfusion setup designed to minimize movement of the needle hub is described. Finally, the judicious use of intraperitoneal transfusions in some cases is suggested.

Intrauterine intravascular transfusions for severe red blood cell isoimmunization: Ultrasound-guided percutaneous approach

Eight pregnancies with severe red blood cell isoimmunization were managed with use of an intravascular approach for intrauterine transfusions. Fetoscopy was not employed, and the procedures were performed percutaneously under direct ultrasound visualization. A total of 16 of 18 attempted transfusions were successfully performed, with four fetuses requiring more than one transfusion. Technical aspects of the procedure as well as its indications, advantages, and drawbacks are discussed.