Midazolam and alfentanil were infused in a totally i.v. anesthetic technique (TIVA) to patients undergoing hysterectomy. Correlations of midazolam plasma concentrations and effects were made during recovery. Due to the high doses of midazolam administered during TIVA, metabolism and not redistribution mainly governed the duration of effects post-infusion. The concomitant administration of alfentanil contributed to the sedative effect, as illustrated by a shift of the concentration-response curve to the left. As a result of these effects, recovery was prolonged and extended over 2-6 h.
The combination of propofol and alfentanil was administered to 20 patients for total intravenous anaesthesia during general surgery. The infusion rates for both drugs were controlled by microprocessors in order to institute constant blood levels adapted to the patients' varying needs. The mean blood level of propofol required for adequate hypnosis during anaesthesia was 2.42 micrograms/ml (SD 0.43). Awakening occurred 7.9 minutes (SD 3.4) after the end of the infusion, at a propofol blood level of 1.59 micrograms/ml (SD 0.34).
Fifty-two female patients who underwent gynaecological operations as day cases received either a short pre-operative hypnotic induction or a brief discussion of equal duration. Hypnotized patients who underwent vaginal termination of pregnancy required significantly less methohexitone for induction of anaesthesia. They were also significantly more relaxed as judged by their visual analogue scores for anxiety. Less than half of the patients were satisfied with their knowledge about the operative procedure even after discussions with the surgeon and anaesthetist.
The effects of alfentanil on the midazolam dose-response curve for hypnosis was studied with response to the verbal command as an end point in 95 patients. The analgesic effect of alfentanil was studied by measuring the threshold for pain caused by pressure on the trapezius muscle with the use of a dolorimeter in 21 patients. The study was randomized, double-blind, and performed on the unpremedicated patients with ASA physical status I or II. Alfentanil was found to reduce the midazolam ED50 value for the induction of anesthesia in a dose-dependent fashion.
We have evaluated the effectiveness of a technique of blended anaesthesia (epidural-general) in 31 patients undergoing major surgery. Thoracic epidural blockade with lidocaina CO2, adrenalin 1/200000, ensures analgesia while induction and hypnosis maintenance were obtained with midazolam, alfentanil, atracurium and N2O/O2. This technique seems able to protect the patients from endotracheal intubation and surgical stress and also to enable a rapid, quiet awakening. The dose of midazolam necessary to maintain hypnosis was inversely proportional to the patient's age.
We have examined interactions between midazolam, propofol and alfentanil using two end-points of light sedation (hypnosis) and anaesthesia. Quantal dose-response curves were determined in 400 female patients for the drugs individually and in combination. At the hypnotic end-point, interactions were analysed by fitting the data to a mathematical model where the response depended on the doses of the three drugs with additional terms included to describe non-additive interactions of the various combinations of the three drugs.
To evaluate the concentration-effect relationships of propofol during recovery after total intravenous anesthesia, 20 female patients undergoing lower abdominal surgery were studied. In 10 patients (Group B) the propofol infusion was supplemented with an epidural block with bupivacaine to evaluate the relation between the blood concentration of propofol and various pharmacodynamic end-points. The remaining 10 patients (Group A) received an alfentanil infusion intravenously instead of the epidural block to assess the dynamic interactions of alfentanil and propofol.
STUDY OBJECTIVES: To investigate the pharmacokinetics of propofol in combination with epidural anesthesia or with intravenous (i.v.) alfentanil infusion, and to investigate the clinical feasibility of this anesthetic technique in lower abdominal surgery. DESIGN: Randomized, open clinical study. SETTING: Operating theaters and postanesthesia recovery unit at the department of gynecology of a university medical center. PATIENTS: 20 healthy, consenting ASA physical status I and II adult female patients undergoing lower abdominal surgery. INTERVENTIONS: A total i.v.
BACKGROUND AND OBJECTIVES: Sedation is often requested during local and regional anesthesia. However, some surgical procedures, such as plastic surgery, require conscious sedation, which may be difficult to achieve. Hypnosis, used routinely to provide conscious sedation in the authors' Department of Plastic Surgery, results in high patient and surgeon satisfaction. The authors conducted a retrospective study to investigate the benefits of hypnosis in supplementing local anesthesia.
Stress reducing strategies are useful in patients undergoing surgery. Hypnosis is also known to alleviate acute and chronic pain. We therefore compared the effectiveness of these two psychological approaches for reducing perioperative discomfort during conscious sedation for plastic surgery. Sixty patients scheduled for elective plastic surgery under local anesthesia and intravenous sedation (midazolam and alfentanil upon request) were included in the study after providing informed consent.