Risk of recurarization during retransfusion of autologous blood withdrawn after injection of muscle relaxants: a comparison of rocuronium and mivacurium.

STUDY OBJECTIVES: In the context of acute normovolemic hemodilution (ANH) recurarization, defined as significant decrease of train-of-four ratio (TOFR) during retransfusion of autologous blood withdrawn after induction of anesthesia, has been described for vecuronium and atracurium. The present study for the first time examined this risk for rocuronium and mivacurium. DESIGN: Prospective, randomized, unblinded clinical study. SETTING: University Hospital in Zurich/Switzerland. PATIENTS: 20 ASA physical status I and II patients undergoing general anesthesia for major maxillofacial surgery. INTERVENTIONS: Anesthesia was induced and maintained with propofol and remifentanil, and rocuronium (0.9 mg kg(-1)) or mivacurium (0.25 mg kg(-1)) was given to facilitate intubation. Thereafter, ANH was started with the removal of 500 mL autologous blood and the subsequent replacement by the same amount of 6% hydroxyethyl starch. The withdrawn blood was stored at 4 degrees C until retransfusion at the end of surgery. MEASUREMENTS: To estimate the risk of recurarization during retransfusion, the degree of recurarization during retransfusion of the autologous blood was assessed mechanomyographically. Plasma levels of rocuronium and mivacurium in the patients' plasma and the autologous blood were determined after its removal and before retransfusion. MAIN RESULTS: The TOFR before retransfusion was 0.97 (range: 0.96 to 0.98) for rocuronium (n = 10) and 0.98 (range: 0.96 to 1.0) for mivacurium (n = 8); n.s. During retransfusion, a slight, but statistically significant reduction of TOFR occurred in one patient in each group. In the mivacurium group, this recurarization occurred 10 minutes after the start of retransfusion; in the rocuronium group, it occurred 20 minutes after retransfusion. The plasma levels of rocuronium and mivacurium in the autologous blood did not change during storage. The plasma concentration of mivacurium in the autologous blood after its removal was 420 +/- 142 microg/L; before retransfusion, it was 384 +/- 147 microg/L. The respective concentrations for rocuronium were 2930 +/- 516 microg/L and 2660 +/- 464 microg/L. CONCLUSIONS: Recurarization during retransfusion may occur with both neuromuscular blocking drugs, mivacurium and rocuronium, when these drugs were injected before the removal of the autologous blood.

Intravenous versus oral iron supplementation for preoperative stimulation of hemoglobin synthesis using recombinant human erythropoietin.

To compare two modalities of iron supplementation for the preoperative stimulation of erythropoiesis using recombinant human erythropoietin (rhEPO), 12 adults in normal hemoglobin and iron status due for elective surgery were randomized to rhEPO 200 U/kg body weight subcutaneously twice weekly combined with either iron sucrose 200 mg intravenously twice weekly or iron sulfate 160 mg/day orally, for 3 weeks preoperatively. Efficacy was measured by the increases over baseline in hemoglobin, reticulocyte count, and ferritin determined 3 days before surgery; preoperative reticulocyte count and ferritin were significantly higher with intravenous iron, whereas the only significant intragroup increases in hemoglobin between time points also occurred in this group. Intravenous iron significantly boosts the hematopoietic response to rhEPO and prevents iatrogenic iron depletion in otherwise healthy candidates for elective surgery.

Alternative methods for reduction of blood loss during elective orthognathic surgery.

Bimaxillary orthognathic surgery and genioplasty are frequently performed to correct dentoskeletal anomalies in otherwise healthy young patients. Until 1990 homologous blood transfusions were routinely necessary for these procedures. The present study describes a protocol of blood-saving measures that was adopted and tested on a continuous sample of 127 patients treated between 1994 and 1997. The protocol comprises acute normovolemic hemodilution, controlled moderate hypotension, positioning the surgical field above the heart level, cell saving, intraoperative homeostasis, preoperative autologous blood donation, administration of recombinant erythropoietin, and acceptance of a low hematocrit perioperatively. This study shows that homologous blood transfusions may be avoided intraoperatively by following the protocol described.

Multimodal strategy for reduction of homologous transfusions in cranio-maxillofacial surgery.

The transfusion of homologous blood carries well-known risks that have prompted efforts to develop alternative techniques. Such measures are of particular interest to patients undergoing elective procedures. A total of 204 patients, out of 1470 patients who consecutively underwent major craniomaxillofacial procedures under general anesthesia over a two-year period, were enrolled in a prospective protocol to reduce homologous transfusion requirements when a blood loss in excess of 500 ml was anticipated. The data were compared with the results of a retrospective control group (n=2890) covering major procedures during the previous four years, when blood-saving measures were applied occasionally, but not based on a global strategy. Techniques for the reduction of homologous transfusions were acute normovolemic hemodilution, controlled moderate hypotension, cell saver and predeposit autologous blood. In addition, preoperative administration of human recombinant erythropoietin was introduced during the last year of the study. These techniques were applied individually or in combination, depending on contraindications specific for each technique, using invasive monitoring in order to maintain intraoperative hemodynamic stability. The goal of this study was to examine the extent to which homologous transfusions may be reduced with the systematic application of transfusion-sparing techniques. Of 204 patients qualifying for the transfusion-sparing protocol, 30 received homologous transfusions. In comparison to the control group, utilization of transfusion-sparing techniques had doubled. The overall reduction in the use of homologous transfusions was highly significant. When acute normovolemic hemodilution, controlled moderate hypotension and the cell saver were used in combination, a greater reduction in homologous transfusions was achieved than with the use of either a single modality or combination of any two. No transfusions were required in patients pretreated with erythropoietin.

[Allo-transfusion saving measures in maxillofacial surgery]. / Fremdblutsparende Massnahmen in der Kiefer-und Gesichtschirurgie.

In terms of a prospective clinical study between June 1994 and May 1996, in 204 patients undergoing maxillo-facial surgeries with a expected blood loss of more than 500 ml a protocol of bloodsaving measures was followed. By means of an additional retrospective study, the consumption of homologous blood and the amount of bloodsaving measures between June 1990 and May 1994 was evaluated. Bloodsaving measures were consisting from acute normovolemic hemodilution, controlled moderate hypotension, cell saving, preoperative autologous blood donation, and administration of rh-erythropoetine. The methoda were applied isolated as well as in combination. Special concerns were given to a stable intraoperative homeostasis and to the acceptance of a low hematocrit perioperatively. Aim of the study was to investigate if, following the protocol, even in major maxillofacial procedures homologous blood transfusions almost completely can be avoided. Out of the 204 patients in the prospective study, only 30 received homologous blood. For the period June 94 to May 96, the reduction of the number of patients receiving homologous blood in relation to the period June 90 to May 94 was 83%. The results indicate that in the years 94 to 96 twice as much patients received bloodsaving measures. These led to a reduction of homologous blood consumption for 427 units in 1990 to 56 units 1996 (p < 0.001). If three measures, i.e. normovolemic hemodilution, cell saving, and hypotension were combined, the need of blood transfusion was at the minimum level. The effective reduction of homologous blood transfusion by consequent application of bloodsaving measures can with these data obviously be demonstrated.