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Background and Objectives: The practice and success of regional anesthesia (RA) are influenced by a number of factors. The aim of this study was to evaluate patients' attitudes toward RA--perhaps the aspect least evaluated in anesthesia practice--and the factors influencing it., Methods: A total of 154 patients (59 male, 95 female) aged 13 to 96 years were subjected to different RA techniques for orthopedic and trauma surgery. On the following day, a nurse not belonging to the surgical area and not aware of the anesthesia technique gave a questionnaire to the patient., Results: After application of the study protocol, 110 patients were evaluated (40 male, 70 female), aged 13 to 96 years (mean, 66 +/- 12). Of these, 15.5% had undergone RA previously. Patient attitude toward RA was mostly either favorable (46.4%) or indifferent (45.5%)--only 6.4% showed a negative attitude. Inconveniences of RA were mentioned by 24.6% of patients, and the most common complaint was the needle puncture involved in the technique (18.1%). Advantages of RA were cited by 82.7% of patients (two or more quoted in 75.3%): the possibility of speaking with relatives during the immediate postoperative period (72.7%), staying awake (71.8%), and the absence of pain during the immediate postoperative interval (37.3%). Regression analysis showed the complaint of needle puncture to be the greatest negative factor., Conclusion: The performance of RA and consequently the knowledge of it acquired by the patients led to an increase in demand among those individuals who previously had expressed doubts about the technique. Previously positive attitudes remained unchanged. The combination of adequate sedation and the correct anesthetic procedure may favor patient acceptance of RA.

Objectives: To analyze the knowledge of anesthesiology possessed by a group of medical students representative of medically trained individuals who have not yet worked in a hospital., Material and Method: Students in their fifth year of medical studies at the University of Valencia were invited to voluntarily and anonymously answer a questionnaire with dichotomous and multiple choice responses covering general and specific aspects of anesthesiology. The survey also collected personal and epidemiological data. One hundred eighty-five questionnaires were returned., Results: The results obtained were analyzed for correlations with epidemiological and personal data (sex, information received, prior anesthesia); no significant correlations were found between these data and correct response. It was believed by 78.4% that the anesthesiologist's function during surgery does not go beyond warning the surgeon of changes in vital signs. Nevertheless, 76.2% asserted that the anesthesiologist's function is to protect the patient during the perioperative period., Conclusion: In comparison with the general population, medical students' training has left them with inadequate understanding of anesthesiology.

Patients with myasthenia gravis respond unpredictably to muscle relaxants and more often suffer respiratory complications after surgery. We describe the use of total intravenous anesthesia with propofol and alfentanil without muscle relaxants is three myasthenic patients classified as Osserman I-IIB. Mean time since appearance of the disease was 1 year and all were undergoing transsternal thymectomy. Time in surgery ranged from 115 to 170 min and mean total dose of propofol was 1,374 mg. In all cases total intravenous anesthesia afforded good conditions for intubation, maintenance during surgery and rapid recovery from anesthesia, with early extubation.

Continuous and single dose spinal anaesthesia were compared in a prospective randomized fashion in 108 patients undergoing orthopaedic surgery. Continuous spinal anaesthesia was via a 20 gauge polyamide multiperforated catheter introduced through an 18 gauge Tuohy needle. Single-dose spinal anaesthesia was performed with a 24 guage x 103 mm Sprotte spinal needle. The mean local anaesthetic dose for the continuous technique was 38.4 (SD 16.5) mg as hyperbaric lignocaine 5%, and for the single-dose spinal anaesthesia 10.8 (SD 2.2) mg as hyperbaric bupivacaine 0.5%. Segmental levels reached with the initial dose did not differ significantly between the two groups. Mean time required to perform continuous spinal anaesthesia was 6.7 (SD 3.9) min, which was longer than for single dose 4.9 (SD 2.8) min (P < 0.05). The onset time and efficacy of anaesthesia, and the duration of the operation were similar in the two groups. Analgesia was inadequate in six patients who received continuous spinal anaesthesia (11%) and one patient who received single dose (2%) (P = 0.18). Hypotension was more frequent in those receiving single doses (P < 0.05). Caudal rotation of the outlet needle orifice to advance the catheter correlated with inadequate analgesia (P < 0.01, r = 0.38). There were no significant differences in the incidence of post-operative complications.

Objectives: To compare the efficacy of propofol and midazolam as sedatives in non-premedicated patients receiving regional anesthesia., Material and Methods: Parameters measured were quality of sedation, intraoperative changes in hemodynamics, respiration and plasma biochemistry as compared with baseline, preinduction and post-anesthetic recovery levels. Forty patients were distributed randomly into two groups. Group P (n = 20) received an infusion of 1% propofol (10 mg/ml) at an initial rate of 6 mg/kg/h for 10 minutes, later decreased to 3 mg/kg/h. Group M (n = 20) received an infusion of 0.3% midazolam with an initial bolus of 0.06 mg/kg along with simultaneous infusion at a rate of 0.05 mg/kg/h., Results: Adequate sedation that was easily controlled during surgery was attained in both groups. The mean doses used were 336.7 +/- 33.7 mg in group P and 10.1 +/- 1.1 mg in group M. No significant changes in hemodynamic and respiratory parameters were observed. Differences between baseline and preinduction levels were found in some analyses, but significant changes during surgery were recorded only for HCO3-. There were no differences in recovery time from the moment infusion ceased until spontaneous eye opening and recall of date of birth. The degree of amnesia was greater in the midazolam group. The lesser amnesia with propofol meant that psychological measures were higher (p < 0.01). No differences in side effects were found., Conclusion: Continuous perfusion of propofol and midazolam for sedation in regional anesthesia are equivalent with respect to efficacy and safety.

Following arthroscopic surgery of the knee, 60 ASA I-II patients were randomly allocated to three different groups (n = 20 each) in an attempt to establish the best postoperative analgesic protocol: 20 ml of bupivacaine (0.25%; 50 mg) intra-articularly (IA) (Group 1); continuous three-in-one lumbar plexus block using a catheter to administer 0.25 ml/kg of bupivacaine (0.25%; single-shot) plus continuous pump infusion of the same drug (0.03 ml.kg-1 x h-1 of 0.25% bupivacaine for 24 h) (Group 2); or 1 mg of morphine with 20 ml of saline IA (Group 3). The results were appraised in a double-blind manner, and the degree of postoperative pain was evaluated by visual analog scale (VAS) at constant hourly intervals for the first 24 h, by the incidence of secondary effects, and by the need for complementary analgesia. Group 2 (three-in-one) VAS values were lower 16 and 24 h after surgery and also globally (P < 0.05), with respect to the other two groups. Five patients in Groups 1 and 3 required complementary analgesia, while three patients in Group 1 suffered nausea. No other secondary effects were observed. We conclude that all three analgesic methods proved efficient, as reflected by the scant requirements for additional analgesics and the degree of expressed patient satisfaction. However, lumbar plexus block (three-in-one) with continuous bupivacaine infusion was most effective, and, although it constitutes an added technique, its scant complications and easy performance make its use advisable.

Objectives: The aim of the study was to prospectively evaluate the results of continuous intradural anesthesia with 18G Tuohy needle and 20G catheter in geriatric patients., Material and Methods: We studied 70 patients with a mean age of 75.9 +/- 10.8 years who were subjected to orthopedic or traumatologic surgery of the lower extremities with a duration of 104.6 +/- 53.6 min., Results: Success index was 95.7%. The initial dose of 1% tetracaine was 10.36 +/- 3.96 mg, the second dose in 29 patients was 7.2 +/- 2.7 mg, the third in 7 cases was 7.40 +/- 2.47 mg, and the total dose was 14.56 +/- 5.6 mg. The metameric level was between T8 and T11 in 80.32% of patients. Peroperative complications were limited to paresthesia in 5 cases (7.14%) during insertion of the catheter, difficulties in catheter placement in one case (1.42%), and accidental catheter extraction during withdrawal of the needle in 2 cases (2.85%). Ten patients (14.28%) presented arterial hypotension (pressure decrease greater than 30% of baseline systolic arterial pressure). During the postoperative phase there were 3 cases of slight headache after dural puncture (4.28%) that recovered with conservative treatment, and one case of lumbalgia at the puncture zone (1.42%)., Conclusions: Continuous intradural anesthesia with the material used in this study is technically easy. It allows to accurately reach the desired metameric level, avoiding massive sympathetic blockade, and providing a steady hemodynamic condition. All these effects are essential for anesthesia in geriatric patients.

The safety of regional anesthesia lies on a set of factors, namely, selection of the adequate technique, skill and proper training from the part of anesthesiologists and use of right equipment. The needle, as a prolongation of the hand of the anesthesiologist, must provide references in technique either by itself or joined to an objective method of nerve localization; this will result in a high percentage of success without iatrogenesis. We have reviewed 1,132 cases of regional anesthesia and grouped them into: intradural anesthesia, epidural anesthesia, and plexus anesthesia. We have evaluated the equipment used according to the success and iatrogenesis directly produced by the needle. Results were analyzed by Fisher's exact test and were statistically significant in the three groups, a fact that would indicate some specificity of the characteristics of the needle in each group of techniques. It would seem reasonable to adopt those techniques appearing to be the most efficacious after analysis in order to increase percentage of success and achieve the greatest safety in the clinical practice of anesthesiologists.

A report of a case of prolonged apnoea after succicurarium in a female patient with abnormal pseudo-cholinesterases is followed by a presentation of a study of pseudo-cholinesterases in 12 members of the family. The value of the use of 4 tests of inhibition of cholinesterase activity in determining the genotype of an individual is emphasised.

The dependence of gluconeogenesis and O2 uptake on PO2 in isolated rat hepatocytes is presented. Maintenance of steady-state PO2 was achieved with an oxystat system (Biochem. J. 236: 765-769, 1986). O2 uptake showed a half-maximal (K0.5) value of 0.5 Torr PO2, whereas the glucose synthesis rate was half-maximal at 1.2 Torr PO2. Halothane at concentrations greater than 1 mM exerted a parallel inhibition of O2 uptake and glucose synthesis at all PO2 levels studied. In contrast, at halothane concentrations less than 1 mM, inhibition of glucose synthesis occurred only at less than 20 Torr PO2. At these low concentrations, halothane was without significant effects on cellular O2 uptake. In isolated mitochondria, inhibition of O2 uptake was already half-maximal at a halothane concentration of 0.5 mM. In this subcellular system the inhibitory effect of halothane was independent of PO2. These results demonstrate that the critical PO2 at which cellular O2 utilization begins to decrease and the PO2 at which glucose synthesis begins to decrease are comparable; both PO2 levels are approximately 5 Torr. The metabolic zonation of the liver lobule is discussed in view of the results presented.

A perivascular axillary plexus block was performed to 87 patients scheduled for orthopedic surgery of hand or arm using an electric nerve stimulator. A catheter was inserted for the postoperative pain control. The success rate was of 90.8% (79 cases); 65 patients (74.7%) presented a complete motor block. Complications were: arterial puncture (3), difficulty in inserting catheter (3), injection out of the sheath (1), pain at the electric stimulation (3). No allergic reactions nor neurologic complications were founded during a year of posterior control.

Some patients present prolonged apnea following the administration of succinylcholine because of substantial portion of plasma cholinesterase (the enzyme responsible for the hydrolysis of this muscle relaxant) is present as an atypical variant. Up to the present four types of cholinesterase genes are known which combination can cause apnea to a greater or less extent. Silent homozygous EsEs present apnea of greatest duration due to the complete absence of cholinesterase activity. The case reported belongs to a family of four members and is an example of this extremely uncommon genetic variant, with a frequency of 1/170.000. To determine total cholinesterase activity genetic typing of the whole family was carried out utilizing the spectrophotometric technique of Szasz and Knedel with butirylthiocholine iodide as substrate. Inhibition studies were performed using benzoylcholine and dibucaine, sodium fluoride, scholine, and sodium chloride as inhibitors.