Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialThe effective dose of dexamethasone for antiemesis after major gynecological surgery.
This double-blind, randomized, placebo-controlled study evaluated the minimum effective dose of dexamethasone for postoperative antiemesis. One-hundred fifty women scheduled for major gynecological surgery were randomly assigned to receive dexamethasone 10 mg (D10), 5 mg (D5), 2.5 mg (D2.5), 1.25 mg (D1.25), or placebo (P) before the induction of general anesthesia. A standardized general anesthesia technique was used. Postoperative pain was treated with bolus IV doses of morphine via a patient-controlled analgesia device. Patients were assessed for incidence of vomiting at 4, 8, 12, and 24 h after surgery. A total of 6, 6, 8, 15, and 19 patients in Groups D10, D5, D2.5, D1.25, and Group P experienced vomiting at least once within the first postoperative 24 h, respectively. Dexamethasone 10 mg, 5 mg, and 2.5 mg was more effective than dexamethasone 1.25 mg or placebo for antiemesis (P < 0.05). The difference in antiemetic effect among the 10 mg, 5 mg, and 2.5 mg groups was similar. The results suggest that 2.5 mg is the minimum effective dose of dexamethasone for postoperative antiemesis in patients undergoing general anesthesia for major gynecological surgery. ⋯ Although dexamethasone is effective for antiemesis, major side effects may accompany its perioperative use. To achieve the best antiemesis with the fewest side effects, dexamethasone 10 mg, 5 mg, 2.5 mg, and 1.25 mg were compared with placebo in surgical patients. We found 2.5 mg to be the minimum effective dose without discernible side effects.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialAttempting to maintain normoglycemia during cardiopulmonary bypass with insulin may initiate postoperative hypoglycemia.
We attempted to develop an insulin administration protocol that maintains normoglycemia in patients undergoing cardiac surgery and to study the effects of intraoperative blood glucose management on serum levels of creatine phosphokinase isoenzyme BB (CK-BB) and S-100 protein. Twenty nondiabetic patients were randomly allocated to receive either "tight control" of blood glucose with a standardized IV insulin infusion intraoperatively (Group TC) or "no control" of blood glucose intraoperatively (Group NC). Perioperative serum levels of glucose, CK-BB, and S-100 protein were determined in all patients. Group TC patients received 90.0 +/- 49.2 units of insulin, whereas Group NC patients received none. Despite insulin, both Group TC (P = 0.00026) and Group NC (P = 0.00003) experienced similar significant increases in blood glucose levels during hypothermic cardiopulmonary bypass. However, mean blood glucose level upon intensive care unit arrival was significantly decreased in Group TC, compared with Group NC (84.7 +/- 41.0 mg/dL, range 32-137 mg/dL vs 201.4 +/- 67.5 mg/dL, range 82-277 mg/dL, respectively; P = 0.0002). Forty percent of Group TC patients required treatment for postoperative hypoglycemia (blood glucose level <60 mg/dL). Substantial interindividual variability existed in regard to insulin resistance. The investigation was terminated after we realized that normoglycemia was unattainable with the study protocol and that postoperative hypoglycemia was unpredictable. All patients in both groups experienced similar significant increases in postoperative serum levels of CK-BB and S-100 protein. These results indicate that "tight control" of intraoperative blood glucose in nondiabetic patients undergoing cardiac surgery was unattainable with the study protocol and may initiate postoperative hypoglycemia. ⋯ The appropriate intraoperative management of hyperglycemia and whether it adversely affects neurologic outcome in patients after cardiac surgery remains controversial. This investigation reveals that attempting to maintain normoglycemia in this setting with insulin may initiate postoperative hypoglycemia.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialThe effect of midazolam premedication on mental and psychomotor recovery in geriatric patients undergoing brief surgical procedures.
To assess the effect of IV midazolam premedication on recovery of cognitive function, 90 geriatric patients (aged 65-81 yr) undergoing brief transurethral procedures were enrolled into this prospective, placebo-controlled, double-blinded study. In all cases, a standard general anesthetic was administered. Thirty minutes before operating room transfer, patients in Group 0.5 mg, Group 2 mg, and Group S received 0.5 mg of midazolam, 2 mg of midazolam, or an equal volume of saline, respectively. Before study-drug administration (baseline), at 15 min thereafter, as well as on arrival in the postanesthesia care unit (PACU), and at 60 min and 120 min, postoperatively, we administered a digit-symbol substitution test, a mini-mental test, a shape-sorter test, and a patient-generated 100-mm visual analog score (0 = minimal and 100 = maximal) for anxiety, sleepiness, and coordination. A 4-point scale was used to assess the degree of patient sedation at 7, 15, and 30 min after study-drug administration. Using a modified Aldrete scoring system, PACU discharge was determined by the PACU staff. Patient anxiety, sleepiness, and coordination scores at baseline and at 15 min after study-drug administration were similar. When compared with saline, midazolam was associated with a significantly (P < 0.05) higher incidence of "deep" sedation. In Group 2 mg, the incidence of a low preoperative Spo2 (<94%) was significantly (P < 0.05) higher when compared with Group S. Emergence, extubation, and orientation times, as well as time to follow commands were unaffected by midazolam premedication. Postoperatively, the digit-symbol substitution test, mini-mental test, and shape-sorter test were similar among the groups. However, time to PACU discharge was significantly (P = 0.03) longer in the two midazolam treatment groups (41 +/-25 min, 60 +/- 32 min, 53 +/- 39 min for Groups S, 0.5 mg, and 2 mg, respectively). Finally, patient satisfaction was unaffected by the randomization schedule. ⋯ IV premedicant midazolam 0.5 mg or 2 mg does not adversely affect mental and psychomotor recovery in geriatric patients undergoing brief surgical procedures. However, midazolam administration significantly prolonged postanesthesia care unit discharge time. Finally, during the preoperative period, midazolam increases the incidence of a Spo2 <94% in a dose-dependent manner.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Comparative Study Clinical TrialLidocaine plus ropivacaine versus lidocaine plus bupivacaine for peribulbar anesthesia by single medical injection.
This study was designed to compare the effects of ropivacaine and bupivacaine, each combined with lidocaine, during peribulbar anesthesia by single medial injection for cataract surgery. One hundred patients were included and randomly divided into two groups of 50, given a mixture of 50% bupivacaine (0.5%) and 50% lidocaine (2%) or 50% ropivacaine (1%) and 50% lidocaine (2%), and 25 U hyaluronidase per mL with each combination. After the first injection, patients given ropivacaine exhibited significantly better akinesia than those given bupivacaine, and significantly fewer were reinjected (19/50 vs 31/50). Among the patients reinjected, peroperative akinesia and analgesia proved satisfactory in both groups. We observed three cases of diplopia caused by retraction of the internal rectus muscle and two cases of moderate ptosis after superonasal reinjection. Hemodynamic profiles were similar in the two groups, and no major side effects were noted during the observation. One percent ropivacaine may be a more appropriate agent than 0.5% bupivacaine for peribulbar anesthesia by single medial injection. ⋯ One percent ropivacaine may be a more appropriate agent than 0.5% bupivacaine for peribulbar anesthesia by single medial injection. Combined with lidocaine, it provides better akinesia and similar analgesia.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialModified continuous femoral three-in-one block for postoperative pain after total knee arthroplasty.
We prospectively studied the continuous "modified" femoral three-in-one block for postoperative pain after total knee arthroplasty. Sixty-two patients undergoing elective knee arthroplasty under spinal anesthesia with bupivacaine (B) and fentanyl were randomized to receive 0.2% B, 0.1% B, or placebo at 10 mL/h for 48 h after an initial bolus of 30 mL of the same solution via the femoral block catheter. The catheters were inserted under the fascia iliaca using a "double pop" technique and a peripheral nerve stimulator and were advanced 15-20 cm cranially. Venous plasma levels of B, desbutylbupivacaine, and 4-hydroxy B were measured daily for 3 days. All patients received patient-controlled analgesia with morphine and indomethacin suppositories for 48 h. Using computed tomography, we evaluated the catheter location for 20 patients. The catheter tips, located superior to the upper third of the sacroiliac joint in the psoas sheath, were labeled as ideally located. The group receiving 0.2% B had a larger block success rate, smaller morphine consumption in the immediate postoperative period (15 vs 22 mg) and during the first postoperative day (9 vs 18 mg), and achieved a greater range of motion in the immediate postoperative period (91 degrees +/- 10 degrees vs 80 degrees + 13 degrees ). Visual analog scores for pain during both rest and activity were low but similar between the groups. Forty percent of the catheters evaluated were ideally located. Ideal location and use of 0.2% B resulted in 100% success of blockade of all three nerves. The S1 root was blocked in up to 76% of patients. The plasma levels of B, 4-hydroxy B, and desbutylbupivacaine were below the toxic range during the infusion. We conclude that continuous fascia iliaca block with 0.2% B results in opioid-sparing and improved range of motion during the immediate postoperative period. Larger doses of bupivacaine may safely be used in the immediate postoperative period if needed. ⋯ Continuous fascia iliaca block with 0.2% bupivacaine reduces opioid requirements and improves range of motion in the immediate postoperative period compared with a placebo and 0.1% bupivacaine. Plasma levels are below the toxic range with this dose. Only 40% of the catheters are positioned in the ideal location. With the smaller dose of bupivacaine, the success rate with this block is small.