Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Clinical TrialIntravenous alprostadil, an analog of prostaglandin E1, prevents thiamylal-fentanyl-induced bronchoconstriction in humans.
Prostaglandin (PG) E(1) relaxes airway smooth muscle in animals. However, no clinical data have been published on the bronchorelaxant effects of IV alprostadil, an analog of PGE(1). We have described experimental thiamylal-fentanyl-induced bronchoconstriction in humans; we now report the effect of IV alprostadil on thiamylal-fentanyl-induced bronchoconstriction. Thirty-two patients were allocated randomly to a control group (n = 16) and alprostadil group (n = 16). Anesthesia was induced with thiamylal 5 mg/kg and vecuronium 0.3 mg/kg and maintained with a continuous infusion of thiamylal 15 mg. kg(-1). h(-1). The lungs of the patients were ventilated with 50% nitrous oxide in oxygen. Twenty minutes after the induction of anesthesia, patients in the control group were given a continuous infusion of normal saline 20 mL/h, and those in the alprostadil group received a continuous infusion of alprostadil 0.2 micro g. kg(-1). min(-1) (20 mL/h), both for 60 min. Both groups were then given fentanyl 5 micro g/kg. Systolic and diastolic arterial blood pressure, heart rate, mean airway resistance (Rawm), expiratory airway resistance (Rawe), and dynamic lung compliance (Cdyn) were measured at the baseline, just before the fentanyl injection (T30), at three consecutive 6-min intervals after fentanyl injection (T36, T42, and T48), and 30 min after fentanyl injection (T60). Baseline Rawm, Rawe, and Cdyn values were comparable between groups. In the control group, both Rawm and Rawe were significantly increased at T36-60, and Cdyn was significantly decreased at T36-60 compared with the baseline. Patients given alprostadil showed no change in Rawm, Rawe, or Cdyn at T36-60. Thus, IV alprostadil seems to have a bronchodilator effect in humans. ⋯ IV alprostadil, an analog of prostaglandin E(1), prevents thiamylal-fentanyl-induced bronchoconstriction in humans. This finding suggests that IV alprostadil has a bronchodilator effect.
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Comparative Study Clinical TrialIntraocular pressure changes during laparoscopy in patients anesthetized with propofol total intravenous anesthesia versus isoflurane inhaled anesthesia.
We examined intraocular pressure (IOP) changes during gynecologic laparoscopy performed under either thiopental-isoflurane anesthesia or total IV propofol anesthesia. Forty adult women with no preexisting eye disease scheduled for gynecologic CO(2) insufflation laparoscopy were included in the study. Heart rate, mean arterial blood pressure, peak and plateau airway pressure, ETCO(2), and IOP (using a Schioetz tonometer) were measured at defined intervals during the procedure. IOP decreased significantly after the induction of anesthesia in both groups, and remained so throughout the procedure in the propofol group. In the isoflurane group, however, IOP was increased significantly above the preinduction level after pneumoperitoneum with head-down position. There was no correlation between IOP and blood pressure or airway pressure. In conclusion, propofol total IV anesthesia may be a better choice for laparoscopic surgery should control of IOP be a concern. ⋯ In this study, we examined the effect of two anesthetic techniques on the intraocular pressure changes during laparoscopic surgery in healthy subjects. Propofol IV anesthesia protected against increases in intraocular pressure with pneumoperitoneum and head-down position.
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Anesthesia and analgesia · Aug 2003
Comparative StudyA comparison of flow rates and warming capabilities of the Level 1 and Rapid Infusion System with various-size intravenous catheters.
Cases involving massive blood transfusion may require the use of specialized blood warmers, such as the Level 1 (L-1) (Level 1 Technologies, Inc., Rockland, MA) or the Rapid Infusion System (RIS) (Haemonetics Corp., Braintree, MA). In this in vitro study, we compared the infusion and warming capabilities of the L-1 (model 1000) versus the RIS using pediatric- and adult-sized IV catheters. The time to infuse 2 L of lactated Ringer's solution and the end temperature after infusion through 20-, 18-, 16-, and 14-gauge catheters, and 4-, 5-, 6-, 7-, and 8.5-French catheters using both the L-1 and RIS were measured. The flow rates of both systems were similar for 18- and 20-gauge catheters; however, the flow rates with the RIS were progressively faster than the L-1 as catheter size increased to >18 gauge. The heating capabilities of the RIS were superior to the L-1 for all catheters >or=16 gauge. We conclude that the RIS was superior to the L-1 for both flow rates and warming capacity for all IV catheters >18 gauge, i.e., those used for cases with massive blood loss. The RIS provided no advantage (with regard to heating and flow) when used with typical pediatric-sized catheters. ⋯ The rapid infusion system is superior to the Level 1 for warming and flow of crystalloid for IV catheters >18 gauge in vitro. The rapid infusion system provides no advantage with catheters typically used in small children (
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Anesthesia and analgesia · Aug 2003
Comparative StudyA comparison of the neurotoxic effects on the spinal cord of tetracaine, lidocaine, bupivacaine, and ropivacaine administered intrathecally in rabbits.
We have reported that increased glutamate concentrations in microdialysate of the cerebrospinal fluid (CSF) may be clue phenomena to elucidate mechanisms of neurotoxicity of intrathecal tetracaine. However, little is known about whether this is true for other local anesthetics. In this study, we compared the effects of local anesthetics on glutamate concentrations in CSF microdialysate and neurologic and histopathologic outcome. Rabbits were assigned into 5 groups (n = 6 in each) and intrathecally received 0.3 mL of NaCl solution (control), 2% tetracaine, 10% lidocaine, 2% bupivacaine, or 2% ropivacaine. Neurologic and histopathologic assessments were performed 1 wk after the administration. Intrathecal local anesthetics significantly increased glutamate concentrations with no significant differences among the four local anesthetics. The sensory and motor functions in the lidocaine group were significantly worse than in the other groups. Characteristic histopathologic changes were vacuolation in the dorsal funiculus and chromatolytic damage of motor neurons. The extent of vacuolation of the dorsal funiculus was in the order of lidocaine = tetracaine > bupivacaine > ropivacaine. Although the differences among the local anesthetics cannot be explained by glutamate concentrations, the results suggest that the margin of safety may be smallest with lidocaine. ⋯ Large concentrations of local anesthetics administered intrathecally increased glutamate concentrations in the cerebrospinal fluid. The margin of safety may be smallest with lidocaine.
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Anesthesia and analgesia · Aug 2003
Propofol-induced anesthesia in mice is mediated by gamma-aminobutyric acid-A and excitatory amino acid receptors.
To elucidate the role of gamma-aminobutyric acid (GABA)(A) receptor complex and excitatory amino acid receptors (N-methyl-D-aspartate [NMDA] and non-NMDA receptors) in propofol-induced anesthesia, we examined behaviorally the effects of GABAergic and glutamatergic drugs on propofol anesthesia in mice. All drugs were administered intraperitoneally. General anesthetic potencies were evaluated using a righting reflex assay. The GABA(A) receptor agonist muscimol potentiated propofol (140 mg/kg; 50% effective dose for loss of righting reflex) induced anesthesia. Similarly, the benzodiazepine receptor agonist diazepam and the NMDA receptor antagonist MK-801 augmented propofol anesthesia, but the non-NMDA receptor antagonist CNQX did not. In contrast, the GABA(A) receptor antagonist bicuculline antagonized propofol (200 mg/kg; 95% effective dose for loss of righting reflex) induced anesthesia. However, neither the benzodiazepine receptor antagonist flumazenil, the GABA synthesis inhibitor L-allylglycine, nor the NMDA receptor agonist NMDA reversed propofol anesthesia. Conversely, the non-NMDA receptor agonist kainate enhanced propofol anesthesia. These results suggest that propofol-induced anesthesia is mediated, at least in part, by both GABA(A) and excitatory amino acid receptors. ⋯ We examined behaviorally the effects of GABAergic and glutamatergic drugs on propofol-induced anesthesia in mice. The results suggest that propofol anesthesia is mediated, at least in part, by both GABA(A) and excitatory amino acid receptors.