Regional-Anaesthesie最新文献

The so-called atraumatic spinal cannula of Sprotte is a modification of the Whitacre spinal needle. It consists of a conical tip with a lateral opening. This cannula (24 G) is said to cause a very low incidence of postspinal headache. In a prospective study, it was compared to a 25 G cannula with a Quincke tip. PATIENTS AND METHOD. The study was carried out on 500 patients who received spinal anesthesia for operations on the lower extremities. The cannulas were randomly assigned to the patients. Puncture characteristics and number of incomplete blocks were evaluated. Postoperatively patients were interviewed on days 1, 3, 5, and 7. Neither the subjects nor the investigator were aware of the type of cannula used. RESULTS. There were no differences with regard to age and sex; 80% of the patients ranged between 15 and 55 years, with a homogeneous spread. Performance of the block was superior with the Sprotte cannula and the incidence of incomplete blocks was lower (1.6% vs 7.8%, P = 0.0011). There was no significant difference with regard to postspinal headache (8.2% vs 7.8%). CONCLUSIONS. The atraumatic cannula had better puncture characteristics, but there was no statistically significant difference with regard to postspinal headaches.

One hundred fifty successful blockades of the lateral cutaneous nerve of the thigh according to the technique of Eriksson with 7-10 ml prilocaine 1% or bupivacaine 0.25% for meralgia paresthetica resulted unexpectedly in 4 cases of complete and 5 cases of partial motor block of the femoral nerve. The fully reversible paralysis or paresis of parts of the lower limb following blockade of the lateral cutaneous nerve of the thigh is explained as a partial 3-in-1 block.

When isobaric spinal anesthesia is applied the level of analgesia is of special interest. This level is influenced by many factors of varying importance. One major factor is the relation between cerebrospinal fluid (CSF) density and the density of local anesthetic solutions. The density of CSF changes with the concentrations of its constituents, e.g., glucose or protein. Because glucose concentrations in CSF change in parallel with blood glucose levels, this may have effects on CSF density and the spread of spinal anesthesia. In 43 patients in two groups (diabetic n = 32, non-diabetic n = 11) the influence of CSF density on the analgesia level achieved with isobaric spinal anesthesia was investigated with special reference to increased glucose levels in blood and CSF. The influence of body height and weight, age and CSF protein content were also studied. There were no statistically significant correlations between any of these factors and the extension of analgesia. The mean blockade level was 1.6 segments lower in the non-diabetic group: this difference was statistically not significant (P greater than 0.05). Anesthesia spread faster in the diabetic group, but this difference was also not significant (P greater than 0.05). For bupivacaine 0.5% alone a density of 1.0010 g/cc was found, while for bupivacaine 0.5% with epinephrine (1:200,000) the density measured was 1.0022 g/cc. There is no correlation (r2 = 0.083) between CSF glucose concentration and CSF density, other factors such as sodium, chloride or CO2, apparently being more important. With CSF density ranging between 1.000 and 1.003 g/cc there was no correlation with the blockade level (r2 = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

The addition of ornipressin to local anesthetics increases the duration of regional anesthesia. A dose of 0.1 unit/ml produces an increase in nerve block duration comparable to adrenaline 5 micrograms/ml. In order to suppress intraoperative bleeding higher concentrations of ornipressin have been used in infiltration anesthesia. This study was designed to examine whether an increase in ornipressin concentration above 0.1 unit/ml causes a further reduction in cutaneous blood flow. Twelve volunteers took part in the study. They received intracutaneous infiltrations of 4 ml lidocaine 0.5% in the volar aspects of both forearms (Fig. 1). The solution was either plain (= Lido) or contained adrenaline 5 micrograms/ml (Lido + A), or ornipressin 0.1 unit/ml (Lido + P1) or 0.2 unit/ml (Lido + P2). Blood flow was measured with a laser Doppler flowmeter; before the infiltration the skin was locally heated to 40 degrees C in order to obtain maximal perfusion (Flow 100); this temperature was maintained throughout the measuring period. The minimal flow after infiltration was calculated as a percentage of Flow 100. Lido caused a significant decrease in flow to 59 +/- 25% (M +/- SD). Lido + A, Lido + P1 and Lido + P2 caused further significant flow reductions, to 19 +/- 21%, 23 +/- 16% and 26 +/- 23%, respectively (Figs. 3, 4). The latency of maximal flow reduction did not differ between the four solutions (Fig. 5). The results show that in infiltration anesthesia an increase in ornipressin concentration above 0.1 unit/ml does not improve superficial vasoconstriction.

Seventy-five patients scheduled for major abdominal operations were randomly divided into four groups, each with a different postoperative analgesic regime. Group I: buprenorphine 4 micrograms/kg was injected i.v. every 4 h. Groups II-IV: all patients were preoperatively supplied with a thoracic epidural catheter that, however, was not used during the operation. Group II: bupivacaine 0.15 ml/kg was injected epidurally every 2 h, the first dose being 0.5%, the top-ups 0.25%. Group III: buprenorphine 4 micrograms/kg in 10 ml saline was given via the catheter and repeated on request. Group IV: these patients received a combined regime. Bupivacaine was injected as in group II, and in addition buprenorphine was added epidurally in the doses and time intervals of group I. After extubation the patients categorized the intensity of postoperative pain twice, first while lying immobile and then after coughing vigorously, using a rating scale with pain scores from 0 to 10. Thereafter, the analgesic regime described above commenced. One hour later the patients' pain scores were again determined. In addition to pain scores, heart rate (HR), mean arterial pressure (MAP) and paCO2 were recorded at the same points in time. The investigation was then interrupted overnight. The analgesic regime continued as described for groups I and II. Patients in group III received 0.15 mg buprenorphine on request i.v., and in group IV bupivacaine was given as in group II with no further buprenorphine. The study recommenced the next morning at 7:00 a.m. After the initial values (pain scores, HR, MAP, paCO2) had been recorded the analgesic program, as scheduled for each patient, restarted. In group IV buprenorphine was again added to bupivacaine and repeated every 4 h, whereas bupivacaine was injected every 2 h. All values were registered hourly until 7:00 p.m., when the investigation was terminated. RESULTS. On the day of operation and during the first few hours on the morning thereafter, analgesia in groups II and IV was considerably better compared to groups I and III (P less than 0.001). We could not statistically demonstrate, however, that analgesia in group IV was superior to that in group II despite the fact that pain scores were lowest in this group, with a median at rest of 0 throughout the study time. In group III (n = 20), epidural buprenorphine failed to produce any acceptable analgesic effect in 6 patients despite correct catheter position. For this reason they were dropped from the study. No patient in any of the other groups, however, was dropped (P less than 0.01). Later in the 1st postoperative day analgesia in groups II and IV lost its superiority at rest, but coughing continued to be less painful in comparison to groups I and III. We noticed that the duration of action of 0.25% bupivacaine, injected as a bolus, was considerably shorter than expected (less than 2 h) and that several patients experienced pain before the next top-up was given...

We report 4 cases of inadvertent subdural injection of local anesthetics among 640 patients receiving epidural anesthesia. In contrast to subarachnoid injection a typical sign was the development of patchy anesthesia in cervical segments and with late onset of symptoms. The case of a 63 year old woman scheduled for aortofemoral bypass surgery in epidural anesthesia is reported. She developed paresthesia, paresis and signs of sympatholysis in both arms 30 min after the injection of 10 ml bupivacaine 0.5% at T10-11. These symptoms lasted for 7 h. Subdural injection was documented using radiopaque dye. Two other cases of probable subdural injection leading to paresthesia and paresis in cervical segments after lumbar injection of 50 or 75 mg bupivacaine are reported. The symptoms began 15-30 min after injection and lasted for 60 min. The fourth case was that of a 26-year-old woman scheduled for cesarean section under epidural anesthesia. Following the injection of 75 mg bupivacaine 0.5% patchy anesthesia extending to T10 developed. By 10 min after an additional injection of 25 mg bupivacaine 0.5% she had paresis and paresthesia in both arms and was unable to cough. Her trachea was therefore intubated; 30 min later the level of anesthesia was below T5 and she could be extubated. Uneventful cesarean section was then performed. These cases demonstrate that as well as subarachnoid injection, inadvertent subdural injection of local anesthetic agents is a potential hazard of epidural anesthesia, not only in patients in an advanced state of pregnancy but also in nonpregnant patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Ropivacaine, congenerate to bupivacaine and mepivacaine has been widely studied in laboratory animals, but there have been few investigations of its efficacy in human epidural anesthesia and peripheral nerve blocks. The aim of this study was to compare the three long-acting local anesthetics (bupivacaine 0.75%, ropivacaine 1% and etidocaine 1%) and to try, with reference to previous studies, to make some statement about the equipotency of ropivacaine relative to bupivacaine and etidocaine. METHODS. In a double blind randomized study, epidural anesthesia was carried out with 20 ml bupivacaine 0.75% (n = 24) and ropivacaine 1% (n = 21). Following this study epidural anesthesia was carried out with 20 ml etidocaine 1% (n = 20) in an open study. Patients with ASA I or II were enrolled in the study. All patients were scheduled for varicose vein stripping. Male and female patients aged 18-70 years and weighing 50-100 kg were included in the study. Patients were all placed in a sitting position, after which the epidural space was identified by the "loss of resistance" technique and a midline approach, at the L-3/4 interspace. Injections of 3 ml of the local anesthetic were given, followed by the remainder of the local anesthetic at 10 ml/min 1 min later. Following injection patients were immediately positioned supine. Analgesia was determined by the pin-prick method and motor blockade was assessed according to the Bromage scale. Heart rate and blood pressure were monitored until 3 h after injection. RESULTS. The latency of analgesia for the first blocked segment (T 12 for bupivacaine and ropivacaine and L-1 for etidocaine) was 6.0 min for bupivacaine 0.75, 5.5 min for ropivacaine 1%, and 5.2 min for etidocaine 1%, and the highest thoracic dermatome (T 5 for bupivacaine, T 4 for ropivacaine and T 7 for etidocaine) was reached after 24 +/- 10, 26 +/- 9, and 30 +/- 18 min for bupivacaine, ropivacaine, and etidocaine, respectively. The duration of sensory anesthesia at the T 10 dermatomal level was 257 +/- 102, 278 +/- 67, and 191 +/- 86 min for bupivacaine, ropivacaine, and etidocaine, respectively. The two-segment regression time was 199 +/- 80 min for bupivacaine, 201 +/- 52 min for ropivacaine, and 174 +/- 81 min for etidocaine. The total duration of sensory block was 340 +/- 103 min for bupivacaine, 428 +/- 65 min for ropivacaine and 223 +/- 62 min for etidocaine, respectively. In the ropivacaine and bupivacaine groups sensory anesthesia was considered adequate for surgery in all cases but one in each group; in the etidocaine group, however 60% of the patients showed inadequate analgesia and all these patients (12/20) required additional analgesics. Bupivacaine achieved an average of motor block 2.1, ropivacaine 2.3, and etidocaine 2.4. CONCLUSION. The results of this study indicate that ropivacaine is an effective local anesthetic agent. Its potency is about equal to that of bupivacaine and much higher than that of etidocaine...

In an open, nonrandomized dose response study, the efficacy of 0.75% ropivacaine (plain) for epidural analgesia was evaluated during 46 orthopedic surgical procedures (18 total hip replacements, 10 knee prostheses, 3 forefoot operations, 14 arthrotomies or osteotomies). Group 1 received 15 ml (112.5 mg); group 2 20 ml (150 mg); and group 3 25 ml (187.5 mg). The times to initial onset (6.7-7.9 min) and to the maximum level of sensory analgesia (25.7, 27.1, and 30.7 min) hardly differed. The mean maximum level of sensory analgesia increased from T6 (group 1), to T5 (group 2) and T3 (group 3), with an absolute maximum level of C3 (statistically not significant). Times for two-segment regression increased from 146 min and 169 to 192 min, for regression of analgesia to T10 from 193 and 189 to 246 min and to T12 from 220 min and 244 to 296 min (significant). The mean maximum durations were 239(+/- 54), 267(+/- 49.8) and 355(+/- 59.2) min. The degree of motor blockade varied with the volume. Motor block grade I was recorded in 100% of cases, and motor block grade II in 64% of patients in group 1, in 73% in group 2, and in 100% in group 3. Motor block grade III was only seen in 7.1% in group 1, 20% in group 2, and 47% in group 3. The duration was 102 min, 133 min and 188 min for grade I, 158 min, 199 min and 263 min for grade III when this occurred. MAP, HF and RPP varied by a maximum of -8.3%, -11.5% and -17.6% from the initial value.(ABSTRACT TRUNCATED AT 250 WORDS)

The activity of the sympathetic nervous system is of fundamental importance in the regulation of vital bodily functions. Impairment of sympathetic neuronal efferences results in considerably disordered effector function, and in some cases even in complete failure. Clinically, this is of great significance, because if an anesthetic agent produces cause the sympathetic system to block, the effects can be serious in individual cases, particularly on the cardiovascular system. If complications are to be avoided, it is essential to assess the degree of block correctly. Clinical monitoring has a variety of applications, a particularly useful one being measurement of the sympathetic system during regional anesthesia, for which quantification of the blocking effect is a clinical necessity and the degree of block needs to be ascertained without delay, for example in the case of spinal or peridural anesthesia. The activity of the sympathetic system can be monitored indirectly by two means: by measuring changes in skin temperature (with reference to all circulatory parameters), as these reflect its influence on the arterioles, and by measuring the skin resistance caused by the eccrinal sweat glands, which are also regulated by the sympathetic system. As the anatomical and functional structure of the system is highly complex a connection between the two measurements cannot necessarily be assumed. The two variables were measured simultaneously during spinal anesthesia and analysed. It was shown that the two measurements correlated well, at least in the statistical middle range, and that skin resistance was by far the faster and more sensitive of the two.