[Intraoperative blood replacement in aortic surgery. Autotransfusion technics]. / Reposición sanguínea intraoperatoria en cirugía aórtica. Técnicas de autotransfusión.

INTRODUCTION: The performance of increasingly invasive surgical techniques involves higher consumption of blood products, along with associated immunological problems and infections. Measures intended to reduce the use of homologous blood products include autologous transfusion and the application of transfusion criteria. We describe our experience with a group of patients scheduled for aortic surgery. PATIENT AND METHODS: Three hundred fifty- eight patients were studied prospectively over a period of 60 months, during which various techniques for conserving blood were applied. Up to 2 units were donated before surgery by patients who had baseline hemoglobin (Hb) counts equal to or greater than 13 g/dl. The donated blood was stored in the form of packed red cells (PRC) and fresh frozen plasma (FFP). Plasmapheresis was performed before surgery whenever a loss of 1,200 ml was expected to occur. Intraoperative salvage of lost blood, with the "Cell- Saver" system, was also used in such cases. No patient was given PRC if Hb was equal to or greater than 10 g/dl; nor was plasma given unless analytical levels indicated need. RESULT: Between 25 and 33% of the patients, depending on age, required no blood products. In up to 55%, self- donated blood was used. Salvage during surgery conserved around 50% of estimated blood lost. The percentage of autologous blood replaced during surgery increase from 21% in 1989 to 38% in 1993. The amount of autologous plasma used also increased with time, reaching nearly 80% of total plasma infused thanks to the introduction of preoperative plasmapheresis. CONCLUSION: The establishment of strict protocols regarding use of blood products and the application of self-donation techniques provided a savings of homologous blood products during the period this study lasted. Preoperative donation of blood was accepted in all cases in which it was indicated and there were no adverse reactions when the autologous blood was replaced.

[Plasma histamine levels after the administration of atracurium or pancuronium in patients undergoing general anesthesia]. / Niveles plasmáticos de histamina tras la administración de atracurio o pancuronio en pacientes sometidos a anestesia general.

OBJECTIVES: To compare the release of histamine induced by atracurium and pancuronium. MATERIAL AND METHODS: We studied 20 patients ASA III undergoing vascular surgery under etomidate anesthesia. Patients were randomly treated with either 0.5 mg/kg of atracurium or 0.1 mg/kg of pancuronium as muscle relaxant agents. Plasma histamine concentration, heart rate, arterial blood pressure, PaO2, and PaCO2 were measured at the basal state and 1.2 and 5 min after administration of the muscle relaxant drug. RESULTS: Plasma histamine concentration at baseline were 0.691 +/- 0.6 ng/ml in the atracurium group and 0.756 +/- 0.612 ng/ml in the pancuronium group. These levels raised up to 2.748 +/- 6.278 ng/ml (atracurium) and 2.553 +/- 5.454 ng/ml (pancuronium). These differences were not statistically significant. The course of the remaining parameters studied in these patients was also comparable between the two groups. There were no clinical manifestations associated with the release of histamine. CONCLUSIONS: Plasma levels of histamine after administration of atracurium were not significantly different from those induced by pancuronium.

[Regional blockage for arterial blood pressure control during placement of head holder in neurosurgery]. / Bloqueo regional para el control de la tensión arterial durante la colocación del craneostato en neurocirugía.

OBJECTIVE: To achieve a hemodynamic stability in neurosurgery during placement of the craniostate, we compared the effects of blocking frontal and occipital nerves with supplementary doses of fentanyl with the effects observed after subcutaneous infiltration of craniostate fixation points. MATERIAL AND METHODS: We studied 34 patients with intracranial masses programmed for craniotomy who were randomly allocated into three groups. Group I received fentanyl 3-5 micrograms/kg, 5 minutes before implantation of craniostate; Group II was treated with subcutaneous infiltration of mepivacaine 2% at craniostate fixation points; and Group III underwent blockade of frontal and occipital nerves. Mean arterial blood pressure was measured at baseline, immediately before craniostate placement, and during the maximal rise induced after placement of the craniostate. RESULTS: Mean arterial blood after craniostate placement was significantly higher in Group I than in Group II (p < 0.01), and higher than in Group III (p < 0.05). CONCLUSIONS: Blockade of frontal and occipital nerves is a useful method for maintaining hemodynamic stability during craniostate placement in neurosurgical patients.