Acute Normovolemic Hemodilution Decreases Transfusion Requirement in Spinal Surgery / 대한마취과학회지

BACKGROUND: Acute normovolemic hemodilution (ANH) is known as the easieat and most economical and the quality of autologous blood saved by it is the best of all methods of autotransfusion. To investigate the efficacy of ANH, we studied whether it could reduce the transfusion requirement in spinal surgery. METHODS: Forty patients were randomly divided into 2 groups. In the hemodilution group (n=20), 2 or 3 units of autologous blood were procured immediately before or after anesthetic induction while Ringer's lactate and pentastarch were infused to maintain normovolemia. All patients received deliberate hypotension induced by labetalol. Perioperative changes of hemoglobin, hematocrit and platelets, the transfusion requirement and the amount of postoperative drainage were compared between each group. RESULTS: Perioperative changes of hemoglobin, hematocrit and platelet showed no significant differences between each group. Less packed RBC were used in the hemodilution group (1.9 2.0 units) than in control group (5.9 6.8 units) (p<0.05). In the control group, 4 patients were transfused with fresh frozen plasma (mean 4.8 units), 3 patients with platelets (mean 13 units) and 1 patient with cryoprecipitate (10 units) while only one patient was transfused with 3 units of fresh frozen plasma in the hemodilution group. Postoperative drainage was significantly less in the hemodilution group (1,494 488 ml) than in the control group (2,476 1,730 ml). CONCLUSION: ANH seems to decrease the transfusion requirement in spinal surgery. Reduction of postoperative wound drainage appears to play an important role in that.

Power Spectral Analysis of Heart Rate Variability during Acute Hypoxia in Fetal Lamb / 대한마취과학회지

BACKGROUND: The aim of the present study was to investigate the changes in the patterns of power spectrum of R-R interval variability on fetal lamb EKG during acute fetal hypoxia. METHODS: Acutely instrumented six fetal lambs during the third trimester of gestation(115 to 145 days) was subjected to reproducible hypoxia by reduction of maternal placental blood flow with complete obstruction of maternal abdominal aorta for 60 seconds. RESULTS: Power spectral density of low, middle and high frequency increased significantly on hypoxia compared to that of baseline state. Power density of high frequency was significantly higher than that of low and middle frequency in baseline state. And the power density of low and high frequency was significantly higher than that of middle frequency in hypoxic state and 1 minute of recovery. CONCLUSIONS: The conclusion is that an increase in power density of low frequency during hypoxia suggested increased sympathetic activity and increased power density of high frequency throughout the experimental procedures suggested active respiratory movements of fetal lambs close to term and increased parasympathetic activity, reflecting rapidly the autonomic nervous system changes of the fetal lambs.