Anesthesia and analgesia
-
Anesthesia and analgesia · Jun 2001
Randomized Controlled Trial Clinical TrialThe effects of small-dose ketamine on propofol sedation: respiration, postoperative mood, perception, cognition, and pain.
We compared the effects of coadministration of propofol and small-dose ketamine to propofol alone on respiration during monitored anesthesia care. In addition, mood, perception, and cognition in the recovery room, and pain after discharge were evaluated. In the Propofol group (n = 20), patients received propofol 38 +/- 24 microg x kg(-1) x min(-1). ⋯ Mood and MMSE scores were higher in the Coadministration group (P < 0.004 and P = 0.001, respectively). Pain scores and analgesic consumption after discharge were less in the Coadministration group (P = 0.0004 and P < 0.0001, respectively). We conclude that coadministration of small-dose ketamine attenuates propofol-induced hypoventilation, produces positive mood effects without perceptual changes after surgery, and may provide earlier recovery of cognition.
-
Anesthesia and analgesia · Jun 2001
Randomized Controlled Trial Clinical TrialInhibition of phosphodiesterase type III before aortic cross-clamping preserves intramyocardial cyclic adenosine monophosphate during cardiopulmonary bypass.
Inotropes are often used to treat myocardial dysfunction shortly after cardiopulmonary bypass (CPB). beta-Adrenergic agonists improve contractility, in part by increasing cyclic adenosine monophosphate (cAMP) production, whereas phosphodiesterase type III inhibitors prevent its breakdown. CPB is associated with abnormalities at the beta-receptor level and diminished adenyl cyclase activity, both of which tend to decrease cAMP. These effects may be increased in the presence of preexisting myocardial dysfunction. We tested the hypothesis that inhibition of phosphodiesterase type III before global myocardial ischemia and pharmacologic arrest results in the preservation of intramyocardial cAMP concentration during CPB. Twenty adult patients undergoing coronary artery bypass grafting with CPB were studied. After CPB was instituted, a myocardial biopsy was obtained from the apex of the left ventricle. Patients were randomized to receive either placebo or milrinone (50 micro/kg) through the bypass pump 10 min before aortic cross-clamping. Another myocardial biopsy was performed adjacent to the left ventricular apex just before weaning from CPB. Myocardial cAMP concentration was determined by radioimmunoassay. Myocyte protein content was determined by the Bradford method by using a commercial kit. There were no significant demographic differences between the groups; however, patients in the Milrinone group had a lower left ventricular ejection fraction than placebo (41% +/- 13% vs 53% +/- 7%; P < 0.05). Patients who received milrinone had larger cAMP concentrations at the end of CPB compared with placebo (21 +/- 12.5 pmol/mg protein versus 12.8 +/- 2.2 pmol/mg protein; P < 0.05). The administration of milrinone before aortic cross-clamping is associated with increased intramyocardial cAMP concentration at the end of CPB. ⋯ The administration of a single dose of milrinone before aortic cross-clamping resulted in significantly larger intramyocardial cyclic adenosine monophosphate concentration in myocardial biopsy specimens compared with controls.
-
Anesthesia and analgesia · Jun 2001
Comparative Study Clinical TrialDifferent responses of ear and finger pulse oximeter wave form to cold pressor test.
The cold pressor test is often used to assess vasoconstrictive responses because it simulates the vasoconstrictive challenges commonly encountered in the clinical setting. With IRB approval, 12 healthy volunteers, aged 25--50 yr, underwent baseline plethysmographic monitoring on the finger and ear. The contralateral hand was immersed in ice water for 30 s to elicit a systemic vasoconstrictive response while the recordings were continued. ⋯ In contrast, no significant change was seen in the ear plethysmographic amplitude measurement, which decreased by 2% +/- 10%. We conclude that the ear is relatively immune to the vasoconstrictive effects. These findings suggest that the comparison of the ear and finger pulse oximeter wave forms might be used as a real-time monitor of sympathetic tone and that the ear plethysmography may be a suitable monitor of the systemic circulation.
-
Anesthesia and analgesia · Jun 2001
Case ReportsTunneled epidural catheters for prolonged analgesia in pediatric patients.
We conducted this retrospective study to document the efficacy and safety, and demonstrate the spectrum of indications for subcutaneously tunneled epidural catheters in the management of prolonged pain in pediatric patients. The charts of 25 patients with prolonged pain that was unresponsive to conventional opioid therapy (10: end stage malignancy, 8: extensive abdominal surgery, 7: trauma, etc.) and who received thoracic, lumbar, or caudal tunneled epidural catheters between 1995 and 1999 were reviewed for efficacy and catheter-related complications (infection or bleeding at the insertion site, toxicity related to local anesthetics, tachyphylaxis and respiratory depression). Tunneled epidural catheters were effective in providing extended analgesia in all subjects. In 14 patients with chronic pain, cumulative 48-h enteral and parenteral opioid requirements were reduced or eliminated after catheter insertion. Catheters remained in place for a median of 11 days (range, 4--240 days) until there was no further need for parenteral analgesia (n = 15), death because of the underlying disease (n = 6), accidental removal (n = 2), or possible infection (n = 2). No serious local or systemic complications (meningitis, epidural abscess, systemic infection, epidural hematoma, or spinal cord injury; seizures, local anesthetic toxicity) occurred related to this technique. Five patients were discharged from the hospital with the catheter for home analgesic therapy. The use of a percutaneously inserted, subcutaneously tunneled epidural catheter is safe, effective, and provides pain relief in situations in which conventional analgesic therapy either fails or is impractical. The technique is one that may be of great value to children suffering from pain. ⋯ Children and adolescents with pain may safely have a spinal catheter placed for a period of time without undo risk of infection or other complications. Spinal catheters provide excellent pain relief, often eliminating the need for riskier medications for painful events such as wound cleansing and dressing changes.
-
Anesthesia and analgesia · Jun 2001
Comparative Study Clinical TrialA comparison of the endotracheal tube and the laryngeal mask airway as a route for endobronchial lidocaine administration.
Drug administration via the endotracheal tube is recommended as a second-line approach in emergency settings such as cardiac arrest. It is unknown what amount of drugs are absorbed when they are given through the laryngeal mask airway as compared with the endotracheal tube. We administered lidocaine at a dose of 2 mg/kg diluted in 10 mL normal saline to 20 anesthetized patients undergoing routine surgical procedures. ⋯ Therapeutic plasma concentrations (>1.4 microg/mL) could be achieved in 10 of 10 patients after endotracheal tube instillation but in only 4 of 10 patients after laryngeal mask instillation (P < 0.05). Peak lidocaine concentrations (2.47 and 1.09 microg/mL) (P < 0.05) and the area under the time versus plasma concentration curve (117.7 and 91.2 microg x min x mL(-1)) (P < 0.05) were higher after lidocaine administration into the endotracheal tube than into the laryngeal mask airway. In conclusion, the laryngeal mask airway is not a reliable route for the recommended dose of endobronchial lidocaine administration compared with the endotracheal tube.