Acta anaesthesiologica Belgica
-
Acta Anaesthesiol Belg · Jan 1988
Balanced anesthesia and patient-controlled postoperative analgesia with fentanyl: minimum effective concentrations, accumulation and acute tolerance.
Minimum effective fentanyl concentrations (MEC) were determined in 230 ASA I-III patients undergoing a variety of elective surgical procedures under balanced anesthesia, and in 40 patients recovering from comparable operations and anesthesia during postoperative intravenous self-administration of fentanyl (demand dose 34.5 micrograms) by means of the On-Demand Analgesia Computer. Following induction of anesthesia with fentanyl 4 micrograms/kg, repetitive fentanyl reinjections (0.1-0.2 mg) were given intraoperatively whenever systolic blood pressure or pulse rate increased to more than 20% of preinduction values, resulting in an intraoperative fentanyl consumption of 4.2 +/- 1.2 micrograms/kg/h. Duration of postoperative patient-controlled analgesia (PCA) was 20.2 +/- 4.3 h during which time 15.5 +/- 12.9 demands per patient were registered, resulting in a postoperative fentanyl consumption of 0.46 +/- 0.35 micrograms/kg/h. ⋯ Individual MECs increased gradually during anesthesia (mean slope 0.0191 ng/ml/min) but decreased under PCA conditions (-0.0008 ng/ml/min); difference not significant. While the postoperative decrease could be explained by diminishing pain intensity during the observation period, the slight intraoperative increase is discussed as acute tolerance rather than as accumulation. It is concluded that repetitive fentanyl injections as indicated by clinical needs will not lead to relevant accumulation in serum, and that analgesic therapy should be individualized both intra- and postoperatively.
-
Acta Anaesthesiol Belg · Jan 1988
The influence of high thoracic epidural analgesia on the cardiovascular system.
The effect of high thoracic epidural analgesia (TEA) on the cardiovascular system was investigated in 10 patients (5 with cardiovascular disease and 5 without known cardiovascular disorder), who were scheduled for a thoracotomy. An epidural catheter was inserted at T1-T2 level. ⋯ TEA did not significantly affect the following parameters: heart rate, mean arterial pressure, cardiac index, central venous pressure, pulmonary capillary wedge pressure, stroke volume index, systemic vascular resistance, pulmonary vascular resistance, right and left ventricular stroke work index. From this study it is concluded that high TEA with bupivacaine has only minor effects on the cardiovascular system.
-
In regional anesthesia sudden and severe complications occur from time to time and may rapidly turn into life threatening situations. Their rarity might well be their most vicious characteristic. Therefore, awareness of the possible complications, careful preparation to cope with them, vigilance enabling prompt recognition of their occurrence and quick administration of the appropriate treatment are all essential for a safe practice of regional anesthesia. The routine use of pulse oximetry is now strongly recommended.