Regional-Anaesthesie最新文献

Since the first paravertebral blockade was carried out by Sellheim in 1905, this method has proved effective for the isolated blockade of spinal nerves. The efficacy of preoperative intercostal blockade (ICB) in combination with neuroleptanalgesia (NLA) or Pentothal-pentazocine-N2O anesthesia (Pe-Pz) was studied (unilateral analgesia for cholecystectomy). Group 1: NLA; group 2: NLA with ICB; group 3: Pe-Pz; group 4: Pe-Pz with ICB. The analgesic requirement differed significantly between groups 1 (0.33 mg fentanyl) and 2 (0.15 mg fentanyl) and groups 3 (63.5 mg pentazocine) and 4 (31.5 mg pentazocine). There were also significant differences in circulatory responses. The maximum deviation from the initial value at the beginning of the operation in group 1 compared to group 2 was pulse rate + 28.7% vs + 2.4%, mean arterial pressure (Part) + 24.6% vs + 3.1%, and systolic pressure (Psyst) + 33% vs +/- 0%; group 3 compared to group 4: pulse rate + 16.4% vs + 3.2%, Part + 24.5% vs 0.0%, and Psyst + 26.5% vs + 196. The times of action of ICB extended from 7.54 h to 11.33 h for partial analgeisa, time to the first dose of analgesic from 12.3 h to 16.9 h (etidocaine 0.5% and 1% respectively without and with epinephrine). The mean blood levels after 100 mg bupivacaine-CO2 rose to 1.16 micrograms/ml after 5 min and reached a maximum after 15 min (1.29 micrograms/ml) as compared to 0.98 micrograms/ml after addition of ornithine-vasopressin. These values are very much higher than those after the use of bupivacaine-HCl solution. Etidocaine and bupivacaine-HCl have comparable durations of analgesia. Toxicologically, both substances can be applied safely with consideration of all pharmacological data for ICB. Of a total of 3,485 intercostal blockades, 2,775 were applied perioperatively (pre- and postoperatively); 265 were carried out for trauma patients (rib fractures) and 445 for therapeutic indications (herpes zoster neuralgia, tumor pain, costovertebral pain). In 8 blocks 10% ammonium sulfate, in 4 blocks absolute alcohol, and in 19 blocks 5% phenol were used for neurolysis. In 2 cases a marginal pneumothorax was seen, which was resorbed spontaneously (0.06%). Altogether 16,270 single intercostal nerves were blocked. Single-session intercostal blockade can be combined as unilateral analgesia with general anesthesia. This combination is characterized by stable circulatory conditions with avoidance of hypertensive reactions. The long-lasting analgesia allows early mobilization and physiotherapy both postoperatively and posttraumatically in patients with unilateral thoracic and abdominal pain.(ABSTRACT TRUNCATED AT 400 WORDS)

Success rates and complications were studied in 178 patients scheduled for brachial block. METHODS. Patients of both sexes aged 9 to 79 years received axillary blocks in order to permit typical surgical procedures of the hand an forearm. The block was performed using the transarterial method described be Dejong. Half of the local anesthetic was administered anterior to and half posterior to the axillary artery. The incidence of successful blocks, latency time, and systemic complications were investigated; 14 days after the blocks, motor function and sensation were examined in order to evaluate the local neurological status. RESULTS. The rate of successful blocks averaged 79% using 40 ml 1% mepivacaine after 12 min latency; this rate was increased to 89% by administering a further 20 ml 1% mepivacaine. Disagreeable sensations from the operative field occurred in 5% and mild symptoms of cerebral toxicity in 2.8% of cases; 1.6% of patients had cardiovascular disturbances such as hypotension or arrhythmias. Local complications such as hematomas were found in 17.5% local pain in the axillary region in 15%, and long-lasting paresthesias in 12% of cases. DISCUSSION AND CONCLUSIONS. The 90% rate of successful blocks is comparable to the range of 86-98% presented in the literature. The success rate depends on the definition of successful block, the experience of the anesthetist, and the volume and concentration of the anesthetic solution administered. The incidence of systemic cardiovascular complications was similar to that in the literature, but we observed fewer symptoms of cerebral toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Isobaric bupivacaine for spinal anesthesia has frequently proved advantageous because of its long and safe analgesia, good motor blockade and low incidence of side-effects. Significant prolongation of analgesia is possible with an epinephrine concentration of as low as 1:200,000 added to bupivacain 0.5%, while optimal prolongation can be achieved by a concentration of 1:100,000. The addition of 1:50,000 epinephrine, however, does not induce any further enhancement. These results are contrary to those of Chambers and Scott, whose short durations of action were possibly due to relative overdosage of epinephrine with a paradoxical reduction of action. The latency period until complete blockade is achieved can be reduced by high epinephrine concentrations (beginning with 1:50,000), a fact which is possibly due to a direct, receptor-induced mechanism of epinephrine. The motor blockade of ankle and toe joints beginning from a concentration of 1:100,000 epinephrine is also prolonged significantly. With all epinephrine concentrations, the overall duration of analgesia could be prolonged significantly, in contrast to the overall duration of motor blockade. Only with free bupivacaine solution did motor and sensory function return at more or less the same time. The period between the beginning and the end of regression for both sensation and motor function was influenced only by the highest epinephrine concentration (1:50,000).(ABSTRACT TRUNCATED AT 250 WORDS)

Unlabelled: The efficacy of conduction anesthesia depends to a great extent on accurate application of the local anesthetic solution (LA) in close proximity to the nerve trunk. The problem with most peripheral nerve stimulators available in the past was that they did not provide a small enough electrical stimulus. Correct positioning of the needle could not be guaranteed if muscle contractions occurred. New current-controlled stimulators have recently been developed with low currents from 0.1 mA upwards. We studied the intensity of stimulus currents eliciting just-visible muscle contractions in the lower leg (m. triceps surae) to see how this influenced the latency and success rate of sciatic nerve block.

Method: In a randomized study, 35 patients (18-68 years, ASA I and II) undergoing elective surgery were investigated. The block was performed by posterior approach using 30 ml 1% prilocaine. The stimulator was switched on with a frequency of 1 impulse/s and a stimulus current of 1 mA when the insulated needle was at a depth of 4 cm. In group 1 (n = 5) LA was injected when the first visible muscle contractions occurred at a current of 1.0 mA, but vanished if the current was diminished. In group 2 (n = 10) the needle was placed if a minimum current of 0.5 mA just triggered a muscular response. In group 3 (n = 10) the threshold current was 0.3 mA and in group 4 (n = 10) 0.1 mA. In all cases direct contact between the needle tip and the nerve was avoided.(ABSTRACT TRUNCATED AT 250 WORDS)

Unlabelled: Propofol was compared to midazolam with regard to its quality as a sedative in regional anesthesia. 81 patients undergoing varicose-vein stripping under epidural anesthesia were divided into two groups: 39 were given propofol and 42 were given midazolam. Both groups were then subdivided into 3 subgroups. 30 min after epidural block, a bolus of propofol 1 mg/kg or midazolam 0.03 mg/kg was given followed by infusion of equipotent solutions: propofol 1.0, 1.5, or 2.0 mg/kg/h or midazolam 0.03, 0.045, 0.06 mg/kg/h. Continuous registration of blood pressure, respiratory rate, and end-expiratory pCO2 was carried out and blood gas analysis was performed every 30 min.

Results: Clinically unimportant changes of circulatory and respiratory parameters were seen. Blood gas analyses showed hypercapnia greater than 50 mmHg in some patients. Brief apnea occurred after bolus propofol in 7.7% of cases and pain during injection in 66.6%. Restlessness: propofol 28.2%, midazolam 9.5%. Upper airway obstruction: propofol 30.8%, midazolam 57.1%. Recovery time after infusion ranged from 130 s with propofol to 26 min with midazolam. Postoperative evaluation included the following questions and responses: Sedation pleasant? propofol 97.5%, midazolam 100%. Sleep during surgery? propofol 94.8%, midazolam 83.5%. Prolonged tiredness? propofol 25.6%, midazolam 69%. Postoperative nausea? propofol 38.5%, midazolam 14.2%. Vomiting? propofol 17.9%, midazolam 11.9%. Our study showed that propofol is highly suitable as a sedative for regional anesthesia in spite of injection pain and frequent postoperative nausea. It is superior to midazolam because of the significantly shorter recovery time, providing improved control-lability and reduced posthypnotic sleep.

Variations in skin resistance are an indicator of a patient's sympathetic nerve activity. To record these variations, a mobile measuring system was developed. Even if this method is not yet used as a clinical routine, it could be helpful in studying the effects of nerve blocks in anesthesia. It seems to be advantageous for estimating the effectiveness of a block, the stress of the patient, and for recognizing very early reactions of a patient's sympathetic system. METHOD. An objective sign of a successful and sufficient block should be diminishing and finally the total lack of skin reaction amplitudes if the block is total. This was measured in a patient (male, 30 years old, nonsmoker, calm type) who suffered from a sudden loss of hearing on the left for four consecutive days when his left stellate ganglion was blocked. The effectiveness of the block was estimated from a two-channel measurement of skin reactions. On one channel the skin resistance of the blocked left side was recorded and on the other, unblocked skin areas of the right side were measured simultaneously. RESULTS. Although all four blocks were successful, which was evidenced by a Horner syndrome as well as elevated skin temperature 1-2 min after the injection of 7 ml bupivacaine (C6/C7), in all four cases residual sympathetic activity could be measured. In Fig. 1, the diminishing amplitudes of channel A as compared with channel B demonstrate this finding after the onset of a block at 2:03 p.m. An interpretation of skin reactions generated by a series of action potentials is given.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrostimulation is a common method of nerve localization. To improve the nerve-stimulating needle, we developed a new bipolar nerve-stimulating electrode with a more convenient extension of its electric field. Figure 1a shows the new nerve-stimulating needle; in Fig. 1b a longitudinal section is depicted. A hollow cannula (1) is surrounded by an isolator (5) that separates the internal electrode (1) from the external electrode (6). The surface of the latter is also covered by an isolator (8). Two cables, (2) and (7), connect the electrodes to a nerve stimulator. Syringes and tubes can be connected to the needle by using the attached part (4). Figs. 2a and b show top- and side views of the needle's sharp end. Except for small parts of the internal (1) and external electrode (2), both electrodes are covered by isolation (3). This arrangement leads to the radially asymmetric extension of the electric field. Studies with animal nerve-muscle preparations showed that the density of the electric field is higher, and thus electrostimulation can be carried out with up to 75% lower impulse amplitude as compared with insulated monopolar electrodes. The main advantage of the new arrangement of electrodes, however, is the dependency between revolution of the nerve-stimulating needle on its axis and the evoked muscle response. Muscle potentials measured by electromyography and respective degrees of needle torsion are shown in Fig. 3 (black circles: bipolar radially asymmetric electrode, white circles: insulated monopolar electrode).(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous spinal anesthesia has not yet found general acceptance, although it is a simple and efficient method. Its main advantage is allowing a reliable block to be built up step by step while carefully monitoring the cardiovascular changes. Postspinal headache can be avoided by restricting the use of elderly patients. At our institution, continuous spinal anesthesia has been administered to geriatric high-risk patients for more than 6 years. We report our experience from the year 1986. PATIENTS AND METHODS. Over a 1-year period continuous spinal anesthesia was used for 157 patients with a mean age of 80.4 years (Fig. 1). Of these patients 111 (70.7%) were classified as ASA 3-5 (Fig. 2). In 2 cases a myocardial infarction dated back only 4 and 11 days. The most common indications for surgery were hip fractures (97, 61.8%) and vascular occlusions (37, 23.6%). An 18G Tuohy needle was used for lumbar puncture. The catheter (Portex minipack) was advanced 3-6 cm into the subarachnoid space. Plain bupivacaine 0.5% was injected in small increments until the desired block level was achieved. The catheters were removed immediately after surgery. RESULTS. In 155 of 157 cases surgery was completed under regional anesthesia. Two patients had to be intubated intraoperatively (1 unexpected laparatomy during vascular surgery, 1 with insufficient block for lumbar sympathectomy). The main technical problem was impossibility to advance the catheter into the subarachnoid space despite free flow of CSF (5 cases). For these patients single-shot spinal (4 cases) or epidural anesthesia (1 case) was used.(ABSTRACT TRUNCATED AT 250 WORDS)

In a randomized, double-blind study, the efficacy of prilocaine 1% (group 1, 30 patients) was compared to mepivacaine 1% (group 2, 30 patients). All patients had a combined sciatic/femoral block for surgery of the lower extremities; a tourniquet was applied in each case. In each patient the block was done using 50 ml of a 1% solution of local anesthetic: 20 ml for the sciatic and 30 ml for the 3-in-1 block. The time to onset of sensory block was approx. 4 min in both groups; the onset of motor blockade averaged 6 min and after 10-12 and 15 min sensory and motor blockades, respectively, were complete. On the average, patients were pain-free for 254 min with prilocaine and 267 min with mepivacaine. Four of 30 patients (= 13%) in group 1 an 6 of 30 patients (= 20%) in group 2 had an unsatisfactory blockade and had to be supplemented by analgesics or general anesthesia. The finding of a significant correlation between the voltage necessary for stimulation and the efficacy of the blockade underlines the importance of correct stimulation when identifying the nerves.