Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1995
Real time versus slow-motion train-of-four monitoring: a theory to explain the inaccuracy of visual assessment.
The present study was undertaken to determine why visual assessment of thumb adduction in response to train-of-four (TOF) stimulation of the ulnar nerve commonly overestimates the ratio that is obtained mechanographically. In patients undergoing general endotracheal anesthesia plus vecuronium for relaxation, 73 data sets were collected at different depths of neuromuscular block in response to supramaximal TOF stimulation. Each data set consisted of: (i) visual estimation of the TOF ratio by an experienced observer; (ii) mechanographic measurement of the TOF ratio with an adductor pollicis force transducer; and (iii) determination of the TOF ratio by measuring the slow-motion thumb displacement recorded on videotape. ⋯ When the change in thumb position as a result of T1-3 was taken into account, the measured height of T4 was 40% less than it was when measured from the original baseline, and the T4/T1 ratio was identical to that obtained mechanographically. For the 23 data sets obtained at low current visual assessment overestimated the mechanographic value to a lesser degree than when obtained at high current. Again, correction for the T1-3 baseline shift improved the accuracy of videotape analysis.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Mar 1995
Randomized Controlled Trial Clinical TrialInteraction between mivacurium and succinylcholine.
We investigated the interaction between mivacurium and succinylcholine when mivacurium was administered during the early recovery from succinylcholine block. We studied 40 adult patients during propofol-alfentanil-N2O-O2 anesthesia. Neuromuscular function was monitored using an electromyographic method (Relaxograph, Datex, Helsinki, Finland). ⋯ During recovery of mivacurium block, the fade was significantly greater, i.e., the train-of-four (TOF) ratio was lower, after succinylcholine administration than without it. Recovery index (T1 25%-75%, mean 4.7 +/- 1.3 min) and the time from the administration of mivacurium to the recovery of TOF ratio 0.7 (mean 20.4 +/- 5.1 min) were not different between the groups. In conclusion, in healthy patients succinylcholine has negligible effects on a subsequent mivacurium-induced neuromuscular block.
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Anesthesia and analgesia · Mar 1995
Effects of verapamil on spinal anesthesia with local anesthetics.
The primary mode of action of local anesthetics is through sodium channel and axonal conduction blockade. Local anesthetics also have extensive effects on presynaptic calcium channels that must function to stimulate the release of neurotransmitters. Thus, interference with calcium channel conductance may enhance spinal anesthesia with local anesthetics. ⋯ Intrathecal lidocaine or tetracaine alone showed the prolongation of TF latency, the increase of MPP threshold, and the increase in motor function scale in a time- and dose-dependent manner. Although intrathecal verapamil alone demonstrated neither sensory nor motor block at the doses used (50-200 micrograms), the combination of lidocaine (20, 50, 100, or 200 micrograms) or tetracaine (10, 20, 50, or 100 micrograms) and verapamil (50 micrograms) produced the more potent and prolonged antinociception and motor block when compared with local anesthetics alone. We interpreted these results to indicate that the intrathecal calcium channel blocker, verapamil, potentiates spinal anesthesia with local anesthetics.
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Anesthesia and analgesia · Mar 1995
Who uses transesophageal echocardiography in the operating room?
A survey was made of 155 anesthesiology residency programs in the United States to determine the patterns of use, responsibility for interpretation, and training of those responsible for intraoperative transesophageal echocardiography (TEE). Survey questions included numbers and types of cases for which TEE is used, who interprets TEE data and how they are trained, the extent of resident training in TEE, and beliefs about the utility of TEE. One hundred eight completed surveys were returned (70% response). ⋯ Forty-two percent of anesthesiologists who use TEE leave a formal interpretation on the chart apart from the anesthesia record, and 43% bill specifically for performing TEE. Although 69% of those responding thought that formal credentials should be required for anesthesiologists to use intraoperative TEE, only 32% reported that their institutions actually mandated this. 38% of those responding stated that they offer a dedicated TEE rotation to their residents, and 13% thought that their graduating residents were trained well enough to use TEE on their own. Among academic institutions responding, the use of intraoperative TEE is nearly universal, responsibility for its interpretation is split almost evenly between cardiologists and anesthesiologists, and there is a disparity between opinions and reality with regard to TEE credentialing for anesthesiologists.
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Anesthesia and analgesia · Mar 1995
Biography Historical ArticleIsabella Coler Herb, MD: an early leader in anesthesiology.