Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1991
Randomized Controlled Trial Comparative Study Clinical TrialIntradermal anesthesia and comparison of intravenous catheter gauge.
A double-blinded randomized prospective study was performed to determine whether alkalinization of lidocaine decreases the pain of intradermal injection and if a larger intravenous catheter (16 gauge) causes more discomfort on insertion than a smaller (20 gauge) catheter when intradermal anesthesia has been used. In a random manner, 100 patients received skin wheals with commercially prepared lidocaine or lidocaine with the addition of sodium bicarbonate before the insertion of a 16- or 20-gauge intravenous catheter. Visual analogue pain scores were obtained after the skin wheal was placed and after the intravenous catheter was inserted. ⋯ However, the catheter insertions pain scores were slightly, but statistically significantly larger in the 16-gauge group regardless of local anesthetic solution used. The addition of sodium bicarbonate to commercially prepared lidocaine does not decrease the pain associated with an intradermal skin wheal. There is a slight increase in patient discomfort upon insertion of a large-bore intravenous catheter, even with the prior use of local anesthetic.
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Anesthesia and analgesia · Oct 1991
Randomized Controlled Trial Clinical TrialOnset of epidural blockade after plain or alkalinized 0.5% bupivacaine.
This double-blind study investigated the effect of adding 1.4% bicarbonate to 0.5% bupivacaine on onset time of sensory and motor blockade after epidural administration. Forty patients were randomly divided into one of two groups. Group 1 received 20 mL of 0.5% bupivacaine (pH, 5.58 +/- 0.12) and group 2 received 20 mL of 0.5% bupivacaine + 0.6 mL of 1.4% bicarbonate (pH, 6.53 +/- 0.06). ⋯ Maximum motor blockade was reached after 30 min in group 1 and after 36 min in group 2. No difference in motor blockade or upward spread of anesthesia was noted between the two groups. The authors conclude that alkalinization of 0.5% bupivacaine offers no improvement in the onset of epidural blockade.
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Anesthesia and analgesia · Oct 1991
Comparative StudySimultaneous cardiac output measurements by transtracheal Doppler, electromagnetic flow meter, and thermodilution during various hemodynamic states in pigs.
The transtracheal Doppler (TTD) method of cardiac output (CO) measurement was compared with thermodilution (TDL) and aortic electromagnetic flow meter (EFM). Simultaneous CO measurements with the three methods were obtained during various hemodynamic states in eight pigs. Cardiac output ranged from 1 to 3 L/min during the study. ⋯ Regression analysis yielded TTD = 0.383 + 0.779 TDL (r = 0.86); TTD = 0.351 + 0.788 EFM (r = 0.87); TDL = 0.077 + 0.95 EFM (r = 0.95). Only a change greater than 0.6 L/min in TTD CO could predict with 95% confidence a change in TDL or EFM CO. These results suggest that, in the CO range of this study, the TTD method does not accurately reproduce the CO measurements obtained by TDL or EFM.
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Several commercially available catheters are currently marketed for continuous intrathecal use. Initial studies using continuous spinal catheters have reported several occurrences of retained fragments after removal of the catheter. Accordingly, we measured the break strength of five commercially available catheters. ⋯ We also tested a commonly used Burron 20-gauge catheter, which is marketed for epidural use, and found it had an average break strength of 6.35 lb. The tested values obtained for the TFX/Rusch catheters were lower than the break strength values supplied by the manufacturers. The authors conclude that the break strength of spinal catheters is one-third to one-half that found for a typical epidural catheter.