Anesthesia and analgesia
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Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Clinical TrialAdding sodium bicarbonate to lidocaine enhances the depth of epidural blockade.
It is controversial whether adding CO2 or sodium bicarbonate to local anesthetics enhances the depth of epidural blockade. Repeated electrical stimulation is a reliable test for assessing epidural analgesia and evokes temporal summation. We used this test to investigate the analgesic effect of lidocaine, with or without CO2 or bicarbonate. Twenty-four patients undergoing epidural blockade with 20 mL lidocaine 2% at L2-3 were randomly divided into three groups: lidocaine hydrochloride, lidocaine CO2, and lidocaine plus 2 mL sodium bicarbonate 8.4%. Pain threshold after repeated electrical stimulation (five impulses at 2 Hz), pinprick, and cold test were performed at S1 and L4. Motor block was assessed. The addition of bicarbonate resulted in higher pain thresholds (P < 0.0001), faster onset of action (P = 0.009), and higher degree of motor block (P = 0.004) compared with lidocaine hydrochloride. We found no significant differences between lidocaine CO2 and hydrochloride. Most of these results were not confirmed by pinprick and cold tests. We conclude that the addition of sodium bicarbonate to lidocaine enhances the depth of epidural blockade, increases inhibition of temporal summation, and hastens the onset of block. Pinprick and cold are inadequate tests for comparing drugs for epidural anesthesia. ⋯ We measured pain perception during epidural anesthesia by delivering electrical stimuli to the knee and foot. We found that the addition of sodium bicarbonate to the local anesthetic lidocaine enhances analgesia. We observed no effect of adding carbon dioxide to lidocaine.
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Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Clinical TrialIntraarticular morphine in the multimodal analgesic management of postoperative pain after ambulatory anterior cruciate ligament repair.
Reconstruction of the anterior cruciate ligament (ACL) is associated with a considerable degree of postoperative pain. Our customary multimodal approach to postoperative analgesia after ambulatory ACL surgery includes perioperative nonsteroidal antiinflammatory drugs, pre- and postincisional intraarticular (I.A.) bupivacaine (B), and postoperative cryotherapy using an external cooling system. This study was designed to determine whether the addition of I.A. morphine (MS) provides improved postoperative analgesia. One hundred patients scheduled for elective ambulatory ACL repair received our standard multimodal therapy. After surgery, patients were randomized to one of four study groups. Group 1 received 30 mL of 0.25% B I.A. Group 2 received 30 mL of normal saline I.A. and 5 mg of MS I.A. Group 3 received 30 mL of 0.25% bupivacaine I.A. and 5 mg of MS I.V.. Group 4 received 30 mL of 0.25% B I.A. and 5 mg of MS I.A. The addition of I.A. B postoperatively provided prolonged analgesia and decreased postoperative pain and analgesic requirements. The addition of MS to I.A. B did not provide additional postoperative analgesia. We conclude that patients undergoing ambulatory ACL repair using our standard multimodal analgesic regimen failed to receive additional postoperative analgesia when MS was added to the I.A. B. ⋯ Patients receiving a multimodal analgesic regimen of perioperative nonsteroidal antiinflammatory drugs, intraarticular bupivacaine, and external cooling did not receive any additional analgesia from intraarticular morphine.
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Anesthesia and analgesia · Feb 1998
Pharmacokinetics and side effects of milrinone in infants and children after open heart surgery.
We investigated the pharmacokinetics and side effects of milrinone in infants and children (< or = 13 yr) after open heart surgery in this prospective, open-label study. Milrinone binding to cardiopulmonary bypass (CPB) circuitry was also examined in out two groups. Children in the small dose group (n = 11) received two 25-microg/kg boluses with a final infusion rate of 0.5 microg kg(-1) x min(-1); those in the large dose group (n = 8) received a 50-microg/kg bolus and a 25-microg/kg bolus with a final infusion rate of 0.75 microg x kg(-1) x min(-1). Blood samples for milrinone concentration were drawn 30 min after each bolus, at steady state, and after discontinuing the milrinone infusion. Pharmacokinetics were evaluated using traditional and nonlinear mixed effects modeling analysis. Milrinone kinetics best fit a two-compartment model. Steady-state plasma levels in the small and large dose groups were within the adult therapeutic range (113 +/- 39 and 206 +/- 74 ng/mL, respectively). The volumes of distribution (Vbeta) in infants (0.9 L/kg) and children (0.7 L/kg) were not different, but infants had significantly lower milrinone clearance (3.8 vs 5.9 mL x kg(-1) x min(-1)). Thrombocytopenia (defined as platelet count < or = 100,000 mm(-3)) occurred in 58%, and the risk increased significantly with duration of infusion. Tachyarrythmias were noted in two patients. Milrinone did not bind to CPB circuitry. We conclude that milrinone is cleared more rapidly in children than in adults. The major complication was thrombocytopenia. ⋯ Most pediatric dosing is based on data published for adults. Infants and children have kinetics that differ from adults. We studied the distribution of I.V. milrinone in infants and children after open heart surgery. Milrinone had a larger volume of distribution and a faster clearance in infants and children than in adults, and dosing should be adjusted accordingly.
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Anesthesia and analgesia · Feb 1998
Pneumoperitoneum as a risk factor for endobronchial intubation during laparoscopic gynecologic surgery.
Patients undergoing gynecological surgery under laparoscopic guidance usually receive general anesthesia with endotracheal intubation and mechanical ventilation. The creation of a pneumoperitoneum and the Trendelenburg position, both of which are used to improve visualization, are associated with cephalad movement of the diaphragm. This may increase the risk of endobronchial intubation. We studied the change in the distance from the tip of the endotracheal tube (ETT) to the carina with a fiberoptic bronchoscope in 30 patients aged 21-40 yr who were undergoing laparoscopic tubal ligation (n = 28) or hysterectomy (n = 2). Measurements were taken in the supine and Trendelenburg positions before and after pneumoperitoneum. The average distance from the ETT to the carina in the supine position was 2.1 +/- 0.8 cm and in the Trendelenburg position was 1.8 +/- 0.8 cm (P = not significant). After insufflation of the abdominal cavity, the mean distance decreased to 0.7 +/- 1.4 cm in the supine position (P < 0.05) and was associated with endobronchial intubation in eight patients. The addition of the Trendelenburg position to an established pneumoperitoneum resulted in minimal displacement (0.54 +/- 1.4 cm, P < 0.05) and one additional endobronchial intubation. We conclude that the insufflation of gas in the abdominal cavity, and not the change in patient position, is the main risk factor for endobronchial intubation in patients undergoing laparoscopic gynecologic surgery. ⋯ This study demonstrated that in anesthetized women, the insufflation of gas into the abdomen during laparoscopy for gynecologic surgery is the main risk factor for migration of the endotracheal tube into a bronchus.
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Anesthesia and analgesia · Feb 1998
A multimodal approach to control postoperative pathophysiology and rehabilitation in patients undergoing abdominothoracic esophagectomy.
This two-armed study was designed to determine whether recovery after esophageal resection may be improved by introducing a new multimodal approach. For 8 mo after the new approach was introduced, all patients undergoing abdominothoracic esophageal resection were studied (Group 2; n = 42). For comparison, a retrospective analysis was also conducted using the data of all patients who had undergone this operation in the 8 mo before the introduction of the new regimen, when the traditional therapy was still in use (Group 1; n = 49). All patients received an epidural catheter at the level of T6-9 before the induction of general analgesia. Afterward, Group 1 patients were operated under general anesthesia. For postoperative pain relief, a mixture of bupivacaine 1.25 mg/mL and sufentanil 1 microg/mL was administered during 5 days without titration of the quality of analgesia. Patients in Group 2 received a preoperative bolus of 10-15 mL bupivacaine 2.5 mg/mL and 20-30 microg sufentanil. After sensory block up to T4 was confirmed, general anesthesia was introduced and intraoperatively combined with a continuous infusion of 5 mL/h of a solution containing bupivacaine 1.75 mg/mL and sufentanil 1 microg/mL. Postoperatively, the epidural infusion rate was adjusted to the need of the individual patients, who were able to administer themselves additional bolus doses of 2 mL with a lockout time of 20 min. Early tracheal extubation and forced mobilization were pursued to improve recovery. Demographic data of both groups were comparable. The pain relief of Group 2 patients was superior to that of patients in Group 1. The nitrogen balance of a subgroup of nine matched pairs of patients with comparable nutritional status was less negative in Group 2 patients on Postoperative Days 1 and 2. Patients in Group 2 were tracheally extubated earlier (mean 6.7 vs 25.1 h after admission to the intensive care unit [ICU]), mobilized earlier (mean 1.2 vs 2.0 days after surgery), discharged from the ICU earlier (mean 1.7 vs 4.0 days), and fulfilled criteria for discharge from the ICU (mean 1.8 vs 4.1 days) and from the intermediate care unit earlier (4.9 vs 6.4 days). We conclude that the multimodal approach may improve recovery and thus reduce costs after abdominothoracic esophageal resection. ⋯ Analgesia and blockade of the perioperative stress response, combined with other aspects of postoperative therapy, may improve recovery after surgery. The intensive care unit stay after esophageal resection was reduced by a new regimen (thoracic epidural analgesia, early tracheal extubation, forced mobilization). This approach may influence the cost of major surgery.