Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2006
Randomized Controlled Trial Comparative StudyPreoperative peribulbar block in patients undergoing retinal detachment surgery under general anesthesia: a randomized double-blind study.
Retinal detachment surgery is frequently associated with significant postoperative pain and emesis in adults. In this randomized, double-blind, controlled study we sought to demonstrate that 1% ropivacaine peribulbar (PB) block in conjunction with general anesthesia (GA) improves operative conditions and postoperative analgesia compared with GA combined with subcutaneous normal saline injection into the inferior eyelid. Thirty-one patients were included in each group. ⋯ In the PB group, fewer patients presented an oculocardiac reflex (6 versus 17; P < 0.01); bleeding interfering with the surgical field was reduced (1 versus 11 patients; P < 0.01); mean time to first nefopam request was longer (148 +/- 99 versus 46 +/- 58 min; P < 0.01); mean nefopam consumption was diminished during the first 6 h after tracheal extubation (18.9 +/- 13.9 versus 28.5 +/- 14.7 mg; P < 0.05); immediate postoperative pain scores were lower; and fewer patients required rescue medication (5 versus 23; P < 0.01). The two groups were similar with respect to the incidence of postoperative nausea and vomiting. Overall, PB block combined with GA improved operating conditions and postoperative analgesia in retinal detachment surgery.
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Anesthesia and analgesia · Apr 2006
Randomized Controlled Trial Comparative StudyDoes bilateral superficial cervical plexus block decrease analgesic requirement after thyroid surgery?
In this randomized, double-blind and controlled study we evaluated and compared the analgesic efficacy of bilateral superficial cervical plexus block and local anesthetic wound infiltration after thyroid surgery. Forty-five patients were assigned to 3 groups. After general anesthesia induction, bilateral superficial cervical plexus block with 0.25% bupivacaine 15 mL in each side was performed in Group I, and local anesthetic wound infiltration with 0.25% bupivacaine 20 mL was performed in Group II. ⋯ Intravenous patient-controlled analgesia was used to evaluate postoperative analgesic requirement. Neither visual analog scale scores nor total patient-controlled analgesia doses were different among groups. We concluded that bilateral superficial cervical plexus block or local anesthetic wound infiltration with 0.25% bupivacaine did not decrease analgesic requirement after thyroid surgery.
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Anesthesia and analgesia · Apr 2006
Randomized Controlled Trial Comparative StudyNitrous oxide and anesthetic requirement for loss of response to command during propofol anesthesia.
The blood concentration associated with loss of response (LOR) to command in 50% of subjects (CP50(LOR)) is an important measure of anesthetic potency. We therefore determined the CP50(LOR) in 40 healthy surgical patients, aged 18-60 yr old, receiving propofol alone or propofol with 67% nitrous oxide (N2O). Patients were randomized to receive 100% oxygen or 67% N2O in oxygen via facemask. ⋯ At testing for response to command, both the measured and target propofol concentrations were significantly larger and BIS values significantly smaller in the propofol-alone group compared with the propofol-N2O group. The CP50(LOR) of propofol in the propofol-alone group was 4.58 mug/mL (95% confidence interval [CI], 1.14-15.36) and 2.67 microg/mL (95% CI, 2.28-3.17) in the propofol-N2O group. The BIS value when 50% of patients responded to command was 60 (95% CI, 55-65) in the propofol-alone group and 75 (95% CI, 73-83) in the propofol-N2O group.
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Anesthesia and analgesia · Apr 2006
Randomized Controlled Trial Comparative StudyGelatin and hydroxyethyl starch, but not albumin, impair hemostasis after cardiac surgery.
We investigated the effect of postoperative administration of colloids on hemostasis in 45 patients after cardiac surgery. Patients were randomized to receive 15 mL kg(-1) of either 4% albumin, 4% succinylated gelatin, or 6% hydroxyethyl starch (molecular weight of 200 kDa/degree of substitution 0.5) as a short-term infusion. There was a comparable decrease in maximum clot firmness of thromboelastometry tracings in gelatin and hydroxyethyl starch groups immediately after completion of the infusion, whereas these values remained unchanged in the albumin group. ⋯ Fibrin formation (clot formation time, alpha-angle) and fibrinogen-dependent clot strength (maximum clot firmness and shear elastic modulus) were more disturbed in the hydroxyethyl starch group than in the gelatin group. We conclude that after cardiopulmonary bypass surgery, both gelatin and hydroxyethyl starch impair clot strength and fibrin buildup, which may predispose patients to increased blood loss. The greatest impairment in hemostasis was seen after hydroxyethyl starch administration, whereas albumin appeared to have the least effect on hemostatic variables.
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Anesthesia and analgesia · Apr 2006
Comparative StudyFibrinogen concentrate reverses dilutional coagulopathy induced in vitro by saline but not by hydroxyethyl starch 6%.
Severe bleeding often induces coagulopathy via loss, consumption, and dilution of clotting factors and platelets. The aims of our in vitro study were to characterize the influence of progressive hemodilution with either NaCl 0.9% or hydroxyethyl starch (HES) 6% on blood clot formation and to analyze the effect of substitution of fibrinogen and platelets on dilutional coagulopathy. Whole blood samples drawn from 8 volunteers were diluted from 20% to 80% of the sample volume with both diluents separately. ⋯ Platelets alone or in addition were not able to improve clot firmness to a clinically relevant extent. Dilutional coagulopathy induced by crystalloids can, in vitro, be effectively reversed by supplementation of fibrinogen. In contrast, HES molecules interfere with fibrin polymerization and, thus, administration of fibrinogen after dilution with HES 6% failed to significantly improve clot firmness.