Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA comparison of the analgesic efficacy of 0.25% levobupivacaine combined with 0.005% morphine, 0.25% levobupivacaine alone, or 0.005% morphine alone for the management of postoperative pain in patients undergoing major abdominal surgery.
We compared the relative efficacy of the combination of the single-isomer local anesthetic levobupivacaine and the opioid analgesic morphine versus both drugs alone for postoperative epidural analgesia after major abdominal surgical procedures. Thoracic epidural anesthesia was produced and maintained with levobupivacaine 0.75% in combination with general inhaled anesthesia without opioids. Patients were randomized to one of three postoperative treatment groups: 1) a combination of levobupivacaine 0.25% and morphine 0.005%; 2) levobupivacaine 0.25%; or 3) morphine 0.005%. Postoperatively, all epidural infusions were commenced at a rate of 4 mL/h. Patients could receive a 4 mL-bolus dose and an increase in the epidural infusion rate by 2 mL/h on request for supplemental analgesia. Patients were also allowed ketorolac as a supplemental analgesic at any time after the first analgesic request. Patients in the combination group had longer times to request for supplemental analgesia as compared with the levobupivacaine only group (P < 0.05) and a trend toward longer time to request as compared with the morphine only group (P = 0.066). Patients in the combination group had lower visual analog scale pain scores at rest and activity at 4 and 8 h and fewer requests for supplemental ketorolac (P < 0.05). In conclusion, this study demonstrates a significant improvement in postoperative analgesic efficacy with the combination of levobupivacaine and morphine for continuous epidural analgesia after major abdominal surgical procedures. ⋯ A significant improvement in postoperative analgesic efficacy is demonstrated with the thoracic epidural administration of the combination of the single-isomer local anesthetic levobupivacaine 0.25% and morphine 0.005% in patients after major abdominal surgical procedures as compared with either drug used alone.
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Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Comparative Study Clinical TrialA comparative study of the postoperative allogeneic blood-sparing effect of tranexamic acid versus acute normovolemic hemodilution after total knee replacement.
Both acute normovolemic hemodilution (NVHD) and tranexamic acid (TA) are potentially useful allogeneic blood conservation strategies after total knee replacement. However, the relative efficacy of these blood-sparing techniques is unknown. Therefore, to compare the postoperative allogeneic blood sparing of NVHD and TA after total knee replacement, we investigated 40 patients in a prospective, single-blinded study protocol. In Group TA, 30 min before deflating the limb tourniquet, an IV infusion of TA, 15 mg/kg, was administered over a 30-min period. Thereafter, a constant IV infusion of 10 mg x kg(-1) x hr(-1) was administered until 12 h after deflation of the limb tourniquet. Before induction of anesthesia, NVHD patients were bled to a target hematocrit of approximately 28%. Intravascular blood volume was maintained with lactated Ringer's solution. All autologous blood was transfused at the end of the surgery. Postoperatively, hematocrit was measured daily. In all cases, a hematocrit <27% was the postoperative transfusion trigger. Before discharge, deep vein thrombosis was excluded by Echo Doppler. Three months after surgery, the incidence of delayed thromboembolic events was assessed. The two groups were demographically comparable. In Group NVHD, 843 mL+/-289 of autologous blood was removed. Despite autologous blood transfusion, during the early postoperative period and until the third postoperative day, the NVHD group had significantly (P < 0.01) lower mean hematocrits when compared with the TA group. Thereafter, because of a significantly (P < 0.0008) greater allogeneic blood requirement in the NVHD group, no statistically significant difference in mean hematocrit recordings was noted among the groups. Blood accumulation in the surgical drain 12 h postoperatively, was significantly (P < 0.0008) higher in the NVHD group (259 mL+/-156) when compared with the TA group (110 mL+/-62). Significantly (P < 0.0008) more allogeneic blood was transfused in the NVHD group (19 U/13 patients) when compared with the TA group (2 U/2 patients). No abnormal Echo Doppler studies were reported. During the 3-mo follow-up period, a deep vein thrombosis and pulmonary embolus were documented in one patient in the NVHD group. We conclude that perioperative hemodynamic stability and allogeneic blood sparing is superior after tranexamic acid administration when compared with normovolemic hemodilution. ⋯ For total knee replacement, when compared with normovolemic hemodilution, tranexamic acid administration is associated with superior perioperative hemodynamic stability and allogeneic blood sparing.
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Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Comparative Study Clinical TrialWound infiltration and drain lavage with ropivacaine after major shoulder surgery.
Subcutaneous infiltration and wound lavage with ropivacaine is an alternative to opioids after major shoulder surgery. However, the efficacy and potential toxicity of this method remain unclear. We therefore evaluated plasma ropivacaine concentrations after shoulder infiltration and wound lavage. We subsequently quantified the efficacy of two ropivacaine concentrations. Patients undergoing major shoulder surgery were anesthetized with alfentanil and propofol. The initial patients (n = 18) received ropivacaine 7.5 mg/mL and ropivacaine plasma concentrations were measured in 15-min intervals. The subsequent 45 patients were randomly assigned to: 1) isotonic saline, 2) 3.75 mg/mL ropivacaine, or 3) 7.5 mg/mL ropivacaine. Ten milliliters of each solution was administered subcutaneously and 20 mL was injected into the wound drain which was clamped for 10 min. Supplemental postoperative pain relief was provided by patient-controlled anesthesia using the opioid piritramid (3.5-mg boluses, 6-min lock-out). Postoperative pain scores were recorded on a 100-mm visual analog scale for 4 h in the initial patients and for 10 h in the second part of the study. Unbound ropivacaine plasma concentrations peaked after 15 min at 0.08+/-0.09 microg/mL; the maximum was 0.30 microg/mL, compared with a toxic threshold of 0.6 microg/mL. In the second part of the study, pain scores were significantly lower after 3.75 mg/mL (20+/-15 mm) or 7.5 mg/mL (10+/-9 mm) ropivacaine than saline (35+/-10 mm). Piritramid requirements differed significantly in the three groups, being highest with saline and lowest with ropivacaine 7.5 mg/mL. We conclude that wound infiltration and lavage with 30 mL ropivacaine 7.5 mg/mL after major shoulder surgery resulted in very low pain scores and opioid requirement. ⋯ Wound infiltration and lavage with 30 mL ropivacaine 7.5 mg/mL after major shoulder surgery resulted in very low pain scores and opioid requirement.
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Anesthesia and analgesia · Dec 1999
Randomized Controlled Trial Comparative Study Clinical TrialCerebrovascular carbon dioxide reactivity during general anesthesia: a comparison between sevoflurane and isoflurane.
We compared cerebrovascular carbon dioxide reactivity during the administration of sevoflurane and isoflurane anesthesia by measuring cerebral blood flow velocity (CBFV) as an indirect measurement of cerebral blood flow. Thirty patients, 20-70 yr old, undergoing lower abdominal surgery and without known cerebral or cardiovascular system disease, were randomly assigned to either sevoflurane or isoflurane treatment groups. Anesthesia was induced with thiopental 5 mg/kg IV and maintained with either sevoflurane or isoflurane in 67% nitrous oxide and oxygen. The CBFV and pulsatility index (PI) of the left middle cerebral artery were monitored with transcranial Doppler. The P(ETCO)2 was increased stepwise from 20 to 50 mm Hg by changing the respiratory rate with a constant tidal volume. At every 5-mm Hg stepwise change in P(ETCO)2, CBFV and PI were recorded. CBFV increased with increasing P(ETCO)2. CBFV was significantly smaller in the isoflurane group at P(ETCO)2 = 20-40 mm Hg than in the sevoflurane group. The rate of change of CBFV with changes in CO2 was larger in the isoflurane group than in the sevoflurane group. PI was constant over time and was not different between groups. In conclusion, hypocapnia-induced reduction of intracranial pressure might be more effective during the administration of isoflurane than sevoflurane. ⋯ Changes in cerebral blood flow caused by the changes of carbon dioxide tension are greater during the administration of isoflurane anesthesia compared with sevoflurane anesthesia. Attempts to decrease intracranial pressure by decreasing carbon dioxide tension may be more successful during isoflurane than sevoflurane anesthesia administration.
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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.