Anesthesia and analgesia
-
Anesthesia and analgesia · Dec 1999
Comparative Study Clinical Trial Controlled Clinical TrialAmino acid-induced thermogenesis reduces hypothermia during anesthesia and shortens hospital stay.
Amino acid infusion during general anesthesia induces thermogenesis and prevents postoperative hypothermia and shivering. We propose that amino acid prevention of hypothermia during anesthesia shortens the hospital stay. Core temperatures and pulmonary oxygen uptake were measured in 45 patients, receiving an IV amino acid mixture, 126 mL/h, before and/or during isoflurane anesthesia and 30 control patients receiving acetated Ringer's solution. At awakening, mean core temperature was 36.5 degrees+/-0.1 degrees C in the amino acid group and 35.7 degrees+/-0.1 degrees C (P < 0.001) in the controls. Energy expenditure increased by 54%+/-9% from baseline in amino acid patients in whom shivering was uncommon, but only by 5%+/-4% (P < 0.001) in control patients, of whom the majority developed postoperative shivering. The estimated difference in hospital stay between the two groups was 2.7 days (CI 95%: 1.3-4.0). Multiple regression analysis showed that the variables best predicting hospitalization were duration of surgery, amino acid treatment, and awakening temperatures. Duration of surgery was similar in the two groups and core temperatures at awakening were a result of amino acid infusion, which indicates that amino acid infusion during anesthesia and surgery was the most important factor for the shorter hospitalization. ⋯ Amino acid infusion during general anesthesia induces thermogenesis and prevents postoperative hypothermia and shivering. Multiple regression analysis indicated that this resulted in a shorter hospital stay.
-
Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Clinical TrialThe effects of intradermal fentanyl and ketamine on capsaicin-induced secondary hyperalgesia and flare reaction.
In this study, we evaluated the effects of intradermal fentanyl and ketamine on capsaicin-induced hyperalgesia and axon-reflex flare. In addition, we obtained dose-response curves for possible local anesthetic effects. Saline (200 microL) and either fentanyl (1 microg or 10 microg in 200 microL) or ketamine (100 microg or 1000 microg in 200 microL) were injected simultaneously into the central volar forearm of 12 healthy volunteers. Nine minutes later, capsaicin (10 microg in 20 microL) was injected intracutaneously exactly between the two injection sites. Areas of touch-evoked allodynia and pinprick hyperalgesia, as well as intensity of pinprick hyperalgesia at the injection sites and axon-reflex flare, were evaluated. Fentanyl did not affect the area or intensity of secondary hyperalgesia. Only the larger concentration of fentanyl locally diminished axon-reflex flare without affecting mechanical detection thresholds. Inhibitory effects of ketamine on intensity of secondary hyperalgesia and axon reflex flare were observed only in the larger concentration. However, this concentration also clearly elevated mechanical detection thresholds. No inhibitory effects of ketamine in the smaller concentrations were observed. We conclude that fentanyl inhibits neuropeptide release on peripheral application without modulating secondary hyperalgesia. Ketamine failed to inhibit both secondary hyperalgesia and axon reflex flare as long as nonlocal anesthetic concentrations were applied. ⋯ We investigated the peripheral effects of fentanyl and ketamine on capsaicin-induced hyperalgesia and axon-reflex flare. In large concentrations, the opioid diminished axon-reflex flare without effects on secondary hyperalgesia. We found no evidence for the involvement of endogenous glutamate in secondary hyperalgesia or axon reflex flare.
-
Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Clinical TrialOral clonidine premedication enhances postoperative analgesia by epidural morphine.
This study was designed to evaluate the effects of oral clonidine premedication on postoperative analgesia by epidural morphine in a prospective, randomized, double-blinded design. Sixty consenting patients, scheduled for total abdominal hysterectomy, were randomly assigned to one of three groups (n = 20 each); the clonidine-morphine group received oral clonidine 5 microg/kg 90 min before arriving in the operating room and epidural morphine 2 mg before induction of general anesthesia, the clonidine-placebo group received oral clonidine 5 microg/kg and no epidural morphine, and the placebo-morphine group received no clonidine and epidural morphine 2 mg. An epidural catheter was placed at the L1-2 or L2-3 interspace, and 1.5% lidocaine was used for surgical anesthesia in all patients. General anesthesia was then induced with propofol, and maintained with a continuous infusion of propofol and 67% nitrous oxide in oxygen during surgery. Four patients were subsequently withdrawn from the study. After surgery, patient-controlled analgesia using IV morphine was used to assess analgesic requirement. Morphine consumptions determined every 6 h after surgery in the clonidine-morphine and placebo-morphine groups were significantly less than the clonidine-placebo group until 12 h after surgery, whereas those of the clonidine-morphine group were significantly less than the placebo-morphine group from 13 to 42 h after surgery. Visual analog (pain) scale (VAS) scores in the clonidine-morphine group were significantly lower than the placebo-morphine group at 48 h at rest, and at 1, 24, 36, and 48 h with movement. Similarly, VAS scores in the clonidine-morphine group were significantly lower than the clonidine-placebo group at 1 and 6 h both at rest and with movement, whereas VAS scores in the clonidine-placebo group were significantly lower than the placebo-morphine group at 24, 36, and 48 h at rest and with movement. The incidence of nausea and pruritus was similar between groups. We conclude that the combination of oral clonidine and epidural morphine produces more potent and longer lasting postoperative analgesia than either drug alone without increasing the incidence of adverse effects after major gynecologic surgeries. ⋯ A small dose of epidural morphine is often used for postoperative analgesia. We found that oral clonidine premedication 5 microg/kg improves the analgesic efficacy of epidural morphine without increasing the incidence of adverse side effects.
-
Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Clinical TrialThe effects of sodium nitroprusside-induced hypotension on splanchnic perfusion and hepatocellular integrity.
The purpose of our study was to investigate the effects of sodium nitroprusside-induced hypotension on splanchnic perfusion and hepatocellular integrity. Thirty patients undergoing radical prostatectomy were allocated randomly to a sodium nitroprusside (SNP) or control group (control). Regional pco2 was measured using gastric tonometry, and the regional to arterial difference in partial pressure of CO2 and intramucosal pH were calculated. The cytosolic liver enzyme alpha-glutathione S-transferase and standard liver enzyme markers (alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase) were also measured. Mean arterial pressure in the SNP group was 50 mm Hg for 97 min during surgery. A significant increase from baseline in regional pco2 (from 40.0+/-4.2 mm Hg to 45.3+/-1.3 mm Hg) and regional to arterial difference in partial pressure of CO2 (from 4.1+/-1.1 mm Hg to 9.7+/-1.4 mm Hg) was seen at 90 min after skin incision only in the SNP group. Intramucosal pH decreased significantly from 7.40+/-0.02 to 7.35+/-0.03 during the same period in this group. Tonometric variables returned to baseline values within 2 h postoperatively. Alpha-glutathione S-transferase concentrations increased significantly in the SNP group from baseline to peak concentrations at the end of surgery (SNP: 9.93+/-4.94 microg/L; control: 5.85+/-1.86 microg/L). A return to baseline values was seen 24 h postoperatively. No significant changes in standard liver enzyme markers were seen throughout the study period. It is concluded, that splanchnic perfusion was transiently impaired during controlled hypotension. This is supported by significant changes in tonometric data. Increased serum levels of alpha-glutathione S-transferase may indicate a disturbance in hepatocellular integrity. ⋯ We studied gastric mucosal tonometry and the cytosolic liver enzyme alpha-glutathione S-transferase to evaluate the effects of controlled hypotension induced by sodium nitroprusside on splanchnic perfusion and hepatocellular integrity. Splanchnic perfusion decreased and alpha-glutathione S-transferase increased during and after a hypotensive period, but returned to baseline values within the first postoperative day, indicating a transient impairment of splanchnic perfusion and hepatocellular integrity.
-
Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of nitric oxide on platelets when delivered to the cardiopulmonary bypass circuit.
Nitric oxide (NO) decreases platelet adhesion to foreign surfaces in the in vitro models of cardiopulmonary bypass (CPB). We hypothesized that NO, delivered into the membrane oxygenator (MO), would exert a platelet-sparing effect after CPB. Forty-seven patients scheduled for coronary artery surgery were randomized to either a NO group, in which NO (100 ppm) was delivered into the MO, or a control group, in which CPB was conducted without NO. Platelet numbers, platelet aggregation response to 2.5-20 microM adenosine diphosphate, and beta-thromboglobulin levels were measured after induction of anesthesia, after 1 h on CPB and 2 h after the end of CPB. Met-hemoglobin levels were measured during CPB. The amount of blood products administered and chest tube drainage were measured in the first postoperative 18 h. NO delivered into the MO for up to 180 min did not increase met-hemoglobin levels above 4%. NO inhibited the platelet aggregation response to 2.5 microM ADP during CPB, otherwise NO had no other detectable effect on the aggregation responses or the levels of beta-thromboglobulin. Platelet numbers were not significantly altered by NO. NO did not alter the use of blood products or chest tube drainage. In conclusion, this study suggests that NO delivered into the MO of the CPB circuit does not significantly alter platelet aggregation and numbers, and does not affect bleeding. ⋯ Nitric oxide affects platelet function. We demonstrated that nitric oxide delivered into the gas inflow of the cardiopulmonary bypass circuit membrane oxygenator does not significantly alter platelet numbers or function.