RESUMEN
Volatile anaesthetics differ in the effects they have on splanchnic haemodynamics and oxygenation. The aim of this study was to evaluate the effects of desflurane and isoflurane as part of a balanced anaesthetic technique on intestinal tissue oxygenation during colorectal surgery. Data were analysed from 44 patients randomly assigned to receive either desflurane (desflurane group, n = 20), or isoflurane (isoflurane group, n = 24) for inhalational anaesthesia. Tissue oxygen pressure (P(tiss)O2) was measured on the serosal side of the large intestine prior to colonic resection (T1) and following the completion of the bowel anastomosis (T2). In addition, haemodynamic and oxygenation parameters were assessed. No difference in mean P(tiss)O2 was observed between the groups at T1 [desflurane group: 8.1 (2.9) kPa vs. isoflurane group: 7.7 (2.7) kPa]. Following completion of the anastomosis (T2) mean P(tiss)O2 was higher in the isoflurane group [9.6 (2.9) kPa] than the desflurane group [7.7 (2.4) kPa, p = 0.025]. During surgery no difference between the groups could be observed with regard to haemodynamics and global oxygenation parameters. The lack of a difference between the groups in P(tiss)O2 before resection of the colon suggests that, under normal conditions, desflurane and isoflurane have comparable effects on intestinal blood flow and oxygenation. However, following local ischaemia, the reactive hyperaemia seems to be better preserved during isoflurane anaesthesia indicated by a local increase in P(tiss)O2blank(p = 0.013) following completion of the bowel anastomosis.
Asunto(s)
Anestésicos por Inhalación/farmacología , Intestino Grueso/cirugía , Isoflurano/farmacología , Consumo de Oxígeno/efectos de los fármacos , Adulto , Anciano , Colon/irrigación sanguínea , Desflurano , Femenino , Hemodinámica/efectos de los fármacos , Humanos , Isoflurano/análogos & derivados , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Presión Parcial , Estudios ProspectivosRESUMEN
OBJECTIVE: To investigate the effects of UV-radiation of autologous blood on bacteria and red blood cells when using intraoperative sampling of autologous blood using a cell separator--an established method for reducing the need for donor blood during surgery--which is reported to have a bacterial contamination rate of 5-75%, due mainly to coagulase-negative staphylococci (CNS). METHODS: Cell-separator blood was diluted to a haematocrit level permitting transmission of 1% of the UV-radiation used in this study (lambda 254 nm, coat thickness 1 mm). CNS samples were irradiated for 2, 4, 10, 20 and 30 seconds. Free haemoglobin and methaemoglobin levels were measured, and erythrocytes examined microscopically at the end of the procedure. RESULTS: Blood samples had to be diluted to a haematocrit of 1% to permit transmission of 1% of the UV light. The optimal irradiation duration was 4 seconds, when bacteria were completely eliminated. Longer irradiation durations were associated with increasing levels of free haemoglobin and methaemoglobin, the levels of which at 4 seconds exposure were 12.5 mg/L and 15.5%, respectively. CONCLUSIONS: It is possible to prevent CNS contamination of cell-separator blood by irradiation with UV light. Prior to clinical application, however, the method will need to be modified to minimize side effects and increase its decontamination efficacy.