IV perflubron emulsion versus autologous transfusion in severe normovolemic anemia: effects on left ventricular perfusion and function.

Intact cardiac compensatory mechanisms are necessary to maintain adequate tissue oxygenation during acute normovolemic hemodilution (ANH). Left ventricular (LV) perfusion, oxygenation and function were analyzed in an experimental whole-body model of profound ANH (Hct 9%) and effectiveness of a perfluorocarbon-based oxygen carrier in maintaining myocardial oxygenation and function was evaluated. A total of 22 anesthetized dogs were hemodiluted to Hct 20% followed by a simulated, controlled blood-loss phase in which dogs were randomized to either: (1) 1:1 exchange of lost blood with autologous red blood cells (RBC-group), (2) 1:1 exchange with a colloid (control-group) and (3) 1:1 exchange with a colloid after a single dose of 1.8 g/kg BW perflubron i.v. (PFC-group). Myocardial oxygen delivery and consumption as well as endocardial perfusion were determined using radioactive microspheres. LV myocardial contractility (LV MC) was assessed from: (1) the relationship between maximum rate of LV pressure increase (LVdp/dtmax) and LV enddiastolic volume (LVEDV) and (2) analysis of the LV endsystolic pressure volume relationship (ESPVR). LV diastolic properties were reflected by (1) minimum rate of LV pressure increase (LVdp/dtmin), (2) slope and intercept of the enddiastolic pressure-volume relationship (EDPVR) and (3) the time-constant of isovolumic LV pressure decline "tau 1/2". Full sets of LV MC data were obtained from 18 dogs (n = 6 per group). LV MC (LVdp/dtmax-LVEDV relation) increased after perflubron administration. At the lowest Hct level, all parameters reflecting LV MC as well as LVdp/dtmin were significantly higher in the PFC-group than in the control-group. After profound normovolemic hemodilution (Hct 9%) superiority of LV MC and LV diastolic properties was found, when myocardial oxygenation was supported by i.v. perflubron emulsion, a temporary O2 carrier.

[Avoidance of homologous blood transfusion despite extreme blood loss]. / Vermeidbarkeit von Fremdblut trotz extremen Blutverlustes.

We report the case of a 22-year-old woman who underwent two-step scoliosis surgery without allogeneic transfusion, although the intraoperative blood loss (3500 ml) during the first procedure was higher than the calculated blood volume (3250 ml). Preoperatively the patient had donated four units of autologous blood. Intraoperatively blood-saving methods were combined. During the first operation acute normovolemic hemodilution (target hemoglobin 9.0 g/dl) was applied and during the second operation controlled hypotension (systolic blood pressure 80 mmHg). Intraoperative auto-transfusion was used in both procedures. During the first operation severe normovolemic anemia (minimal hemoglobin 3.5 g/dl) was accepted while the patient was ventilated with FiO2 1.0. The hemoglobin concentration was 8.6 g/dl after the first procedure and had increased to 11.6 g/dl 4 weeks after the second procedure. No severe complications occurred during the postoperative phase. This case report shows that also in surgical procedures with extreme blood loss any allogenic transfusion can be avoided by the combination of blood-saving methods, acceptance of low intraoperative transfusion trigger and ventilation with 100% oxygen.

Inhalation of prostacyclin (PGI2) for 8 hours does not produce signs of acute pulmonary toxicity in healthy lambs.

OBJECTIVE: To study the potential side effects and toxicity of inhaling prostacyclin (PGI2) aerosol for 8 h. DESIGN: In a prospective, randomized study 14 healthy lambs received either PGI2 (n = 7) or 0.9% NaCl (n = 7) as an aerosol for 8 h. SETTING: Institute for Surgical Research of the Ludwig-Maximilians-University of Munich. INTERVENTIONS: All animals were studied under general anesthesia in a prone position. They were first intubated endotracheally and later tracheotomized. PGI2 solution (median dose 28 ng/kg per min) or 0.9% NaCl was administered with a jet nebulizer (delivery rate 4-10 ml/h; mass median diameter of aerosol particles 3.1 microns). Bronchoalveolar lavage was performed before and after the inhalation period to collect epithelial lining fluid of alveoli. MEASUREMENTS AND RESULTS: Hemodynamic and respiratory parameters, systemic resorption (plasma levels of 6-keto-prostaglandin-F 1 alpha), in vitro bleeding time, collagen-induced platelet aggregation and global biochemical and cellular composition of the epithelial lining fluid were examined in order to assess the side effects and signs of acute pulmonary toxicity induced by inhaled PGI2. No statistically significant differences were found between the PGI2 and the control groups for any of the parameters examined. CONCLUSION: Inhalation of PGI2 (28 ng/kg per min) over a period of 8 h in healthy lambs does not produce major side effects or acute pulmonary toxicity.