Anesthesia and analgesia
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The purpose of this study was to gain new insights in the role of succinylcholine in the initiation of malignant hyperthermia (MH). The intravenous (i.v.) administration of succinylcholine (2.0 mg/kg) induced fasciculations and masseter spasm in both normal swine and those susceptible to MH. However, the amplitudes and durations of generalized fasciculations were significantly greater in the susceptible animals that subsequently developed a fulminant episode of MH: succinylcholine induced not only tachycardia, hyperthermia, contractures, and increases in PaCO2 and lactate, all classic indicators of an episode, but also an initial severe hypotension. ⋯ In the pretreated and untreated susceptible swine, dantrolene was an equally effective treatment. Plasma catecholamine levels after succinylcholine administration were increased only in the susceptible swine without the pancuronium pretreatment. We concluded that the effects of succinylcholine on skeletal muscle and/or on other tissues play a significant role in the initiation of a MH episode in swine with this genetic disorder, and that these effects are not dependent on an abnormal sensitivity for succinylcholine-induced skeletal muscle fasciculations in these animals.
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Anesthesia and analgesia · Jul 1994
Comparative StudyComparison of high-dose thrombin time with activated clotting time for monitoring of anticoagulant effects of heparin in cardiac surgical patients.
The activated clotting time (ACT) is routinely used for monitoring of heparin effects during cardiopulmonary bypass (CPB). However, ACT is not a specific assay for heparin and may be influenced by several other factors, which may be misleading with regard to the proper administration of heparin and protamine. In this pilot study, we compared a new test, the high-dose thrombin time (HiTT), with the conventional ACT test for both in vitro and in vivo heparin-induced anticoagulation. ⋯ Hypothermia and hemodilution occurring during CPB did not alter HiTT results. ACT also correlated well with both heparin concentration and HiTT before CPB, but the linear relationship was lost during CPB. Our results suggest that HiTT is a useful assay for monitoring heparin effects during cardiac surgery, even during hypothermia and hemodilution.
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Anesthesia and analgesia · Jul 1994
Comparative StudyNasal intubation with Bullard laryngoscope: a useful approach for difficult airways.
Since the original technique using the Bullard laryngoscope requires considerable practice to be reliable, we have developed an easier method with a directional-tip endotracheal tube through the nostril. We first examined the feasibility of our method in patients with or without difficult airways. ⋯ We found that a combination of the Bullard laryngoscope and the Endotrol tube had a higher probability of accessing the center of the glottis than the others. In conclusion, nasal insertion of a directional-tip tube assisted by the Bullard laryngoscope is an assured and prompt procedure for intubating the tracheas of patients with difficult airways.
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Anesthesia and analgesia · Jul 1994
Randomized Controlled Trial Comparative Study Clinical TrialThe role of continuous background infusions in patient-controlled epidural analgesia for labor and delivery.
The use of a background infusion with intravenous patient-controlled analgesia (IV-PCA) increases drug consumption without any additional contribution to analgesia. There are no data on the potential advantage of a background infusion administered with patient-controlled epidural analgesia (PCEA) for labor and delivery. Sixty women were randomized to one of four groups and received either: (a) demand dose PCEA (demand dose = 3 mL; lockout interval = 10 min); (b) continuous infusion plus demand dose PCEA (two separate infusion rates: 3 mL/h and 6 mL/h); or (c) a fixed-rate continuous epidural infusion (CEI) at 12 mL/h. ⋯ However, use of PCEA (in whatever mode) provided a 35% dose-sparing effect in comparison to CEI. The PCEA groups receiving no background infusion or a 3-mL/h background infusion had a greater need for physician-administered supplemental bupivacaine during the first stage of labor. While not statistically significant, a trend toward increased need for supplementation was seen in these same patient groups over the entire course of labor and delivery.(ABSTRACT TRUNCATED AT 250 WORDS)