Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2003
Randomized Controlled Trial Clinical TrialIntraoperative intravenous ketamine in combination with epidural analgesia: postoperative analgesia after renal surgery.
We designed this double-blinded, randomized, controlled study to evaluate the effect of small-dose ketamine IV in combination with epidural morphine and bupivacaine on postoperative pain after renal surgery. An epidural catheter was inserted, and the administration of morphine and bupivacaine was started before surgery. Forty patients were assigned to one of two groups (ketamine or control). The ketamine group was administered a ketamine bolus and infusion during surgery. The median visual analog pain scale (VAS) scores at rest were significantly lower in the ketamine group during the first 6 h (P < 0.01). VAS pain scores on coughing were also significantly lower in the ketamine group (P < 0.01). Cumulative postoperative total analgesic consumption was less in the ketamine group on Days 1 and 2 (P < 0.001). The first analgesic demand time was shorter in the control group (9.2 +/- 11.5 min) than in the ketamine group (22.3 +/- 17.1 min) (P < 0.0001). The incidence of nausea and pruritus was more frequent in the control group (P < 0.05). In conclusion, postoperative analgesia was more effective when spinal cord and brain sensitization were blocked by a combination of epidural morphine/bupivacaine and IV ketamine. ⋯ Renal nociception conducted multisegmentally by both the spinal nerves (T10 to L1) and the vagus nerve cannot be blocked by epidural analgesia alone. We demonstrated that IV ketamine had an improved analgesic or opioid-sparing effect when it was combined with epidural bupivacaine and morphine after renal surgery.
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Anesthesia and analgesia · Oct 2003
Randomized Controlled Trial Clinical TrialContinuous wound infiltration with ropivacaine reduces pain and analgesic requirement after shoulder surgery.
After achieving a reduction of pain scores for 10 h with a single dose wound infiltration after shoulder surgery, we examined in a prospective, placebo-controlled and double-blinded study the analgesic effects of continuous wound infiltration with different concentrations of ropivacaine. Forty-five patients undergoing shoulder surgery were randomly assigned into three groups to receive single dose wound infiltration with 30 mL saline (group S) or ropivacaine 7.5 mg/mL (groups R2 and R3.75) after skin closure. Postoperatively, patients received a continuous wound infiltration with saline (group S), ropivacaine 2 mg/mL (group R2) or ropivacaine 3.75 mg/mL (group R3.75) for 48 h. Supplemental pain relief was provided by IV patient-controlled analgesia with the opioid piritramide. At 1, 2, 3, 4, 24, and 48 h postoperatively visual analogue scale (VAS) values (0-100 mm), piritramide requirements and side effects were registered. Plasma levels of ropivacaine were measured preoperatively and at 24 h and 48 h after surgery. Until 48 h VAS values were smaller in group R3.75 compared with group S (group R3.75, 8 +/- 9 mm; group S, 31 +/- 14 mm; P < 0.005), whereas 4 h and 48 h postoperatively VAS values were even smaller in group R3.75 compared with group R2 (P < 0.05). Cumulative piritramide consumption was always smaller in groups R2 and R3.75 compared with group S (1-24 h, P < 0.005; 48 h, P < 0.05). Plasma ropivacaine levels remained less than the toxic threshold. We conclude that continuous postoperative wound infiltration with ropivacaine, especially using 3.75 mg/mL, provides smaller VAS values and opioid requirement in comparison with saline after shoulder surgery. ⋯ The continuous postoperative wound infiltration after shoulder surgery with different concentrations of ropivacaine, 2 mg/mL and 3.75 mg/mL, results in lower pain scores and opioid requirement compared with infiltration with placebo. Plasma levels of ropivacaine remained less than the toxic threshold.
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Anesthesia and analgesia · Oct 2003
Clinical TrialBlood use in patients undergoing coronary artery bypass surgery: impact of cardiopulmonary bypass pump, hematocrit, gender, age, and body weight.
We investigated the impact of cardiopulmonary bypass pump (CPB), hematocrit, gender, age, and body weight on blood use in patients undergoing coronary artery bypass graft surgery at a major university hospital. Participants were 1235 consecutive patients undergoing primary coronary artery surgery over a period of 2 yr (1999 and 2000); 681 patients underwent coronary surgery with use of CPB, and 554 patients underwent off-pump coronary artery bypass surgery using a median sternotomy incision. There were 881 males and 354 females. Average packed red blood cells (PRBC) transfusion for patients on CPB was 3.4 U compared with 1.6 U for the off-pump group (P = <0.001). Patients on CPB received more frequent PRBC transfusion (72.5%) compared with 45.7% of off-pump patients (P = <0.001). Average PRBC transfusion for males was 2.2 U compared with 3.6 U for females (P = <0.001). A lower percentage of males (52.6%) than females (79.4%) received transfusion (P = <0.001). The impact of CPB, off-pump status, preoperative hematocrit <35%, gender, age >or=65 yr, and weight
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Anesthesia and analgesia · Oct 2003
The hemodynamic and metabolic effects of shivering during acute normovolemic hemodilution.
To assess the hemodynamic and metabolic effects of shivering during extreme normovolemic hemodilution, we anesthetized 16 pigs with fentanyl-midazolam-pancuronium. Mild hypothermia (36.5 degrees +/- 0.1 degrees C) was induced by surface cooling, and the animals were randomized to either a control group (hemoglobin 118 +/- 3 g/L) or a hemodilution group (hemoglobin 52 +/- 2 g/L). In the latter group, blood was replaced with an isotonic Ringer's acetate/dextran 70 solution. Shivering was allowed to occur by a controlled decrease in the infusion rate of pancuronium. Shivering increased oxygen consumption (VO(2)) in both groups (P < 0.001). Initially, this was predominantly compensated for by an increased oxygen extraction ratio (ER), but when VO(2) was 2.3 +/- 0.2 times baseline, critical levels of mixed venous oxygenation (SVO(2) = 18% +/- 2%; PVO(2) = 22.5 +/- 1.5 mm Hg) and ER (82% +/- 3%) were recorded in anemic animals. Control animals did not reach critical levels until VO(2) was maximal (3.7 +/- 0.3 times baseline). Maximal attained VO(2) was less (2.9 +/- 0.1 times baseline) in the anemic animals (P = 0.01), and at this stage two of these pigs had myocardial lactate production, one of which died in ventricular fibrillation. Coronary perfusion pressure was significantly less (P < 0.001) in the anemic animals. We conclude that in this experimental model, maximal shivering as measured by VO(2) was limited in hemodiluted animals, and left ventricular oxygen balance was marginal, as evidenced by a decreased lactate uptake and extraction. ⋯ The effect of acute increases in oxygen consumption (shivering) on severely anemic individuals has not been evaluated. In this experimental model, left ventricular oxygen balance was marginal, as evidenced by decreased lactate extraction.
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Anesthesia and analgesia · Oct 2003
Case ReportsSciatic nerve palsy after total hip arthroplasty in a patient receiving continuous lumbar plexus block.
We report a case of late-onset postoperative sciatic palsy after total hip arthroplasty in a 30-yr-old man with congenital hip dysplasia. The patient was receiving continuous lumbar plexus blockade and had received low-molecular-weight heparin 3 h before the onset of symptoms. Anatomic distinction between the nerve block and the sciatic palsy facilitated rapid diagnosis and treatment of a periarticular hematoma, with resulting neurologic recovery. This case illustrates that, with the expanded role of regional anesthetic techniques in acute pain management, the finding of a new postoperative deficit must be jointly investigated by both anesthesiologists and surgeons. Timely and open communication between services is critical because rapid intervention may be essential to achieving full recovery of an affected nerve. ⋯ A case is presented of sciatic palsy developing after total hip arthroplasty in a patient receiving a continuous lumbar plexus block. The case highlights various issues in the use of continuous peripheral nerve blocks for postoperative analgesia.