Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2005
Randomized Controlled Trial Comparative Study Clinical TrialInterscalene brachial plexus block with bupivacaine and ropivacaine in patients with chronic renal failure: diaphragmatic excursion and pulmonary function changes.
In this randomized, double-blind study, we compared the anesthetic characteristics and pulmonary function changes of 0.33% bupivacaine and 0.33% ropivacaine used for interscalene brachial plexus (IBP) anesthesia in patients with chronic renal failure. Forty-two patients undergoing IBP anesthesia for creation of arteriovenous fistulas were randomly allocated to receive either 30 mL of 0.33% bupivacaine (Group B) or 0.33% ropivacaine (Group R). Block onset time, diaphragmatic excursion (ultrasonographic evaluation), and free plasma concentrations of bupivacaine and ropivacaine were evaluated. ⋯ The decreases in Group B were larger than those in Group R (P < 0.05). Three patients in Group B and one in Group R had mild respiratory problems (P > 0.05). Concentrations of bupivacaine and ropivacaine were below toxic levels rather than "normal range." We conclude that pulmonary function decreased more after IBP with 0.33% bupivacaine than with 0.33% ropivacaine.
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Anesthesia and analgesia · Apr 2005
Randomized Controlled Trial Clinical TrialThe effects of a small-dose naloxone infusion on opioid-induced side effects and analgesia in children and adolescents treated with intravenous patient-controlled analgesia: a double-blind, prospective, randomized, controlled study.
Opioids are frequently associated with side effects such as nausea, vomiting, and pruritus. We hypothesized that a prophylactic, continuous small-dose naloxone infusion would reduce the incidence of opioid-induced side effects without affecting analgesia or opioid consumption. In this prospective, double-blind, randomized, controlled clinical trial, we studied 46 postoperative patients (M:F, 21:25), averaging 14 +/- 2.5 yr and 53 +/- 17 kg, at the start of morphine IV patient-controlled analgesia. ⋯ Morphine consumption (1.02 +/- 0.41 mg . kg(-1) . d(-1) versus 1.28 +/- 0.61 mg . kg(-1) . d(-1)), pain scores at rest (4 +/- 2 versus 3 +/- 2), and pain scores with coughing (6 +/- 2 versus 6 +/- 2) were not different. We conclude that, in children and adolescents, a small-dose naloxone infusion (0.25 microg . kg(-1) . h(-1)) can significantly reduce the incidence and severity of opioid-induced side effects without affecting opioid-induced analgesia. When initiating morphine IV patient-controlled analgesia for the treatment of moderate to severe pain, clinicians should strongly consider starting a concomitant small-dose naloxone infusion.
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Anesthesia and analgesia · Apr 2005
Randomized Controlled Trial Clinical TrialNon-zero basal oxygen flow a hazard to anesthesia breathing circuit leak test.
The non-zero basal flow (BF) of oxygen in anesthesia machines has been set to supply the basal metabolic requirement of oxygen. However, there is no scientific evidence of its necessity. In this study we sought to clarify whether non-zero BF affects leak detection during preanesthetic inspections. ⋯ The leak detection rate of leak test with BF was less than without BF (P < 0.01). We demonstrated that non-zero BF of oxygen decreases the leak detection rate and is an obstacle for leak detection, especially for small leaks. Therefore, we recommend that breathing circuit leak tests should be performed in the absence of BF of oxygen.
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Anesthesia and analgesia · Apr 2005
RGS proteins: new players in the field of opioid signaling and tolerance mechanisms.
In this article we review recent advances in our understanding of the crucial role of the Regulator of G protein Signaling (RGS) proteins in opioid signaling mechanisms and opioid tolerance development. Opioids exert their physiologic effects via complex G protein-coupled receptor-signaling mechanisms, and RGS proteins are now known to tightly regulate the G protein signaling cycle. ⋯ There have been more than 20 RGS proteins reported in the literature, and multiple RGS proteins have been shown to negatively regulate G protein-mediated opioid signaling, facilitate opioid receptor desensitization and internalization, and affect the rate at which opioid tolerance develops. Using RGS proteins as targets for future drug therapy aimed at modulating opioid effectiveness in both acute and chronic pain settings may be an important advance in the treatment of pain.
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Anesthesia and analgesia · Apr 2005
The impact of carrier flow rate and infusion set dead-volume on the dynamics of intravenous drug delivery.
The dynamics of IV drug delivery resulting from drug infusions connected to main-line crystalloid carriers can be complex and depend on infusion set dead-volume, drug flow rate, and carrier flow rate. While the concept of dead-volume is intuitive, a lack of appreciation of the interaction with the carrier and drug flow rates can lead to unintended clinical effects resulting from large variations in the delivery rate of potent drugs. We derived mathematical models to quantify these interactions. ⋯ The method of connecting an infusion to a carrier and the use history affects the dynamics of drug delivery. Thus, although complex, the impact of infusion set architecture and changes in carrier and drug flow rates are predictable. These quantitative studies may help optimize the safe use of IV drug infusion systems.