Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2004
Letter Case ReportsDamage to the three-way valves by a clear propofol formulation.
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Anesthesia and analgesia · Apr 2004
The effects of alfentanil on cytosolic Ca(2+) and contraction in rat ventricular myocytes.
Previous investigations of the effects of potent opioid analgesics on the heart have concentrated on effects on contraction magnitude and time course, but little is known about their effects on cytosolic Ca(2+) regulation in cardiac tissue. In this study, we sought to assess the effects of alfentanil on contractility and the cytosolic Ca(2+) transient in ventricular myocytes isolated from the rat ventricle by enzymatic dispersion. Cells were loaded with fura-2 and electrically stimulated at 1 Hz, and Ca(2+) transients and contractions were recorded optically at 30 degrees C. Alfentanil 10(-8) and 10(-7) M had no effect on the magnitude or time course of contraction or the cytosolic Ca(2+) transient. In contrast, 10(-6) M alfentanil induced a significant (P < 0.001) positive inotropic effect, increasing the mean (+/-SEM) unloaded shortening from 7.3 +/- 1.3 microm to 8.7 +/- 1.4 microm (an increase of 20%), with no change in the cytosolic Ca(2+) transient. Myofilament Ca(2+) sensitivity was significantly (P = 0.027) increased by 10(-6) M alfentanil but unaffected at 10(-7) M alfentanil. These data show that 10(-6) M alfentanil, a concentration close to the maximum clinical free plasma concentration, induced a positive inotropic effect due to sensitization of the myofilaments to Ca(2+) rather than to modified cytosolic Ca(2+) regulation. ⋯ Alfentanil, at concentrations achieved in clinical practice, increased contraction in ventricular cells by a mechanism involving an increase in the sensitivity of the contractile apparatus to Ca(2+).
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Comparative Study Clinical TrialAnalgesic effects of intraarticular sufentanil and sufentanil plus methylprednisolone after arthroscopic knee surgery.
We studied the effect of intraarticular saline, sufentanil, or sufentanil plus methylprednisolone after knee arthroscopic meniscectomy. In a double-blind randomized study, 60 patients undergoing knee arthroscopic meniscectomy were allocated to groups receiving intraarticular saline, intraarticular sufentanil 10 microg, or sufentanil 10 microg plus methylprednisolone 40 mg at the end of arthroscopy during general anesthesia. Postoperatively, pain levels at rest and during movement (i.e., active flexion of the knee) were measured by a visual analog scale and were significantly decreased in the sufentanil and sufentanil plus methylprednisolone groups compared with the control group. Moreover, we found that there was a significant reduction in intraarticular sufentanil and sufentanil plus methylprednisolone in the postoperative consumption of analgesics. We also found that the use of intraarticular sufentanil or sufentanil plus methylprednisolone after knee arthroscopic meniscectomy decreases the amount of supplementary analgesic needed for pain relief during the early postoperative period. In addition, we detected that sufentanil provided prolonged pain relief up to 24 h when compared with control, whereas when we combined sufentanil plus methylprednisolone, we found that it further reduced pain and use of analgesics when compared with sufentanil. ⋯ The combined use of intraarticular sufentanil (10 microg) and methylprednisolone (40 mg) in arthroscopic meniscectomy surgery reduced both postoperative pain scores and the use of additional analgesics.
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Anesthesia and analgesia · Apr 2004
Intrathecal clonidine and bupivacaine have synergistic analgesia for acute thermally or inflammatory-induced pain in rats.
We investigated the interaction between spinally administered bupivacaine and clonidine using an animal model of acute and inflammatory pain. Rats implanted with lumbar intrathecal catheters were injected intrathecally with saline (control), bupivacaine (1 to 100 microg), or clonidine (0.1 to 3 microg) and tested for their responses to thermal stimulation to the tail (tail flick test) and subcutaneous formalin injection into the hindpaw (formalin test). The effects of the combination of bupivacaine and clonidine on both stimuli were tested by isobolographic analysis. General behavior and motor function were examined as side effects. The 50% effective doses of bupivacaine and clonidine were significantly smaller when combined compared with each single drug in both the tail flick test (2.82 and 0.11 microg versus 7.1 and 0.29 microg, respectively) and phase 1 (0.24 and 0.009 microg versus 5.7 and 0.15 microg) and phase 2 (0.31 and 0.012 microg versus 3.2 and 0.16 microg) of the formalin test. Side effects were decreased by the combination. These results suggest a favorable combination of intrathecal bupivacaine and clonidine in the management of acute and inflammatory pain. ⋯ The analgesic interaction between intrathecally administered bupivacaine and clonidine was examined during acute thermal and inflammatory-induced pain in rats. The analgesia produced by the combination of these two drugs was synergistic in both acute thermal and inflammatory induced pain, with a decrease in behavioral side effects.