Regional-Anaesthesie
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Regional-Anaesthesie · Sep 1990
Randomized Controlled Trial Clinical Trial[No effect of injection volume on sensory and motor blockade in isobaric spinal anesthesia].
The authors were interested to find whether the course of sensory and motor blockade in isobaric spinal anesthesia was determined by the dose or the volume of the anesthetic agent. In a randomized double-blind study in 60 patients, each underwent isobaric spinal anesthesia with 17.5 mg bupivacaine. In three groups of 20 patients, this dose was administered as 3.5 mg bupivacaine 0.5%, 7 ml bupivacaine 0.25% or 10 ml bupivacaine 0.175%. ⋯ The rate of development, the maximal spread or intensity, and the regression of sensory and motor blockade did not differ in the three groups. The only difference was that the complete regression was shorter following 10 ml bupivacaine 0.175% (P less than 0.05). It is therefore concluded that the dose, and not the volume, determines the course of sensory and motor blockade of isobaric spinal anesthesia.
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Regional-Anaesthesie · Sep 1990
Comparative Study[The effect of patient positioning on the spread of sensory blockade in hyperbaric and isobaric spinal anesthesia using bupivacaine].
Two prospective studies were performed to assess for how long after the subarachnoid injection of local anesthetics changes in position influence the cephalad spread of sensory blockade. Divergent accounts have been given by other groups. Besides the patient's position other factors may influence the cephalad spread of sensory blockade such as baricity of local anesthetics, speed of injection, dose, volume, barbotage and size of needle. ⋯ With hyperbaric bupivacaine the mean spread of sensory blockade (n = 15) was 16 segments (T7). Following the Trendelenburg position the spread was extended by 2.0 segments (p less than 0.05). After 20 min in the supine position following isobaric bupivacaine the mean spread of the sensory blockade (n = 15) was 15.4 segments (T7/8).(ABSTRACT TRUNCATED AT 400 WORDS)
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Regional-Anaesthesie · Sep 1990
[In electric nerve stimulation can the distance from the nerves be inferred from the intensity of muscle contraction? Possible parameters and sources of error].
Electrical nerve stimulation is a useful tool in regional anesthesia; it assists in locating the nerves. This investigation deals with electrical resistances at adhesive electrodes attached to the skin. The influence of external electrical resistance on the stimulating impulse is demonstrated. ⋯ Axillary puncture of the brachial plexus resulted in the following values: (1) A stimulating impulse (cross-wave) of 1 mA and 1 ms exerted at a distance of 4 mm to the nerve induced a contraction of strength 3. (2) Reducing the impulse at this site by one-half (0.55 mA) resulted in just-visible contractions (strength 1). (3) Advancing the cannula at a stimulating impulse of 0.55 mA inside the neurovascular sheath again produced contractions of strength 3. (4) Performing the puncture with a blunt needle and tracing a distinct resistance, the impulse of 0.6 mA elicited contractions of strength 2. The needle tip was still outside the vascular nerve sheath. If this resistance was overcome and the needle tip lay inside the neurovascular sheath, the impulse could be reduced by one-half (0.32 mA) to produce contractions of strength 2.
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Regional-Anaesthesie · Sep 1990
[The effect of injection speed and needle gauge on the spread of sensory blockade in spinal anesthesia].
Unanimity has not yet been reached on the influence of injection speed and needle size on the spread of sensory blockade in spinal anesthesia. While McClure et al. [6] proved that a change in injection speed had no effect on the spread of the blockade, Lanz et al. [4] showed in their investigation that increasing injection speed increases the spread of the blockade. The influence of needle size has hardly been investigated so far. ⋯ No direct relation could be proved between the different injection speeds and the spread of the blockade. Our results are hardly comparable with those of other investigators, since other groups have used different local anesthetics or performed investigations in vitro. The use of large spinal needles is associated with spread of the spinal block to a significantly higher level than is achieved with thinner needles.(ABSTRACT TRUNCATED AT 400 WORDS)