Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2002
Randomized Controlled Trial Clinical TrialThe median approach to transsacral epidural block.
Transsacral epidural block may be useful for surgery or cancer pain affecting the rectal, anal, or urethral region. The procedure through the dorsal sacral foramen is difficult because of the long insertion route. We investigated whether the transsacral epidural block could be simplified by using a median approach instead of a lateral approach through the foramen. Thirty patients for transurethral resection of bladder tumor had a catheter placed 5 cm cephalad at S2-3 (15 patients) or caudal (15 patients) epidural space using a 19-gauge Tuohy needle by the median approach. Lidocaine 2% 15 mL was administered for anesthesia. Anesthesia level (sensory block to cold), hemodynamics, and side effects were compared between the two approaches. The success rate of anesthesia was 87% for transurethral resection of bladder tumor (proximal anesthesia level higher than T10) and 100% for the sacral region (S1-5) in both groups. The highest level of anesthesia (median, T8 in the S2-3 group and T9 in the caudal group) was obtained in 20 min in both groups. No side effects were observed. We conclude that the median transsacral epidural approach is technically feasible in adults and presents an alternative to caudal block. ⋯ The median approach to transsacral epidural block has been described in children. We found that it is technically feasible in adults and presents an alternative to caudal block for procedures on the rectal, anal, or urethral region.
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Anesthesia and analgesia · Oct 2002
Randomized Controlled Trial Clinical TrialPropofol in a medium- and long-chain triglyceride emulsion: pharmacological characteristics and potential beneficial effects.
Hypertriglyceridemia is a possible unwanted effect during long-term propofol sedation while using a formulation containing long-chain triglycerides (LCT) from soybean oil. The use of propofol formulated in a solvent consisting of medium-chain triglycerides (MCT) and LCT might reduce the risk. Because a new solvent may affect the pharmacological profile of propofol, in this prospective, randomized, controlled, and double-blinded study we compared the pharmacodynamic and kinetic characteristics of propofol diluted in MCT/LCT fat solution with those of propofol formulated in LCT fat emulsion. In addition, serum triglyceride levels were measured during and after the administration of both drugs. Thirty patients likely to require mechanical ventilation over at least 48 h were randomized to receive either propofol 2% MCT/LCT (Group 1) or propofol 2% LCT (Group 2). Infusion rates of propofol (2.34 +/- 0.83 mg. kg(-1). h(-1) in Group 1 versus 2.31 +/- 0.6 mg. kg(-1). h(-1) in Group 2), the plasma propofol concentrations during infusion (0.95 +/- 0.53 versus 0.98 +/- 0.32 micro g/mL), and the concentrations and arousal behavior after discontinuation of the drug did not show significant differences. Plasma triglyceride concentrations during sedation did not differ between the groups, whereas there was a tendency toward a more rapid triglyceride elimination in Group 1 after termination of the propofol administration. ⋯ Propofol diluted in an emulsion of medium- and long chain-triglycerides shows equivalent pharmacological properties during long-term sedation compared with its hitherto well known formulation containing long-chain triglycerides only. In addition, potential favorable effects on the plasma triglyceride profile could be found.
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Anesthesia and analgesia · Oct 2002
Randomized Controlled Trial Clinical TrialPropacetamol as adjunctive treatment for postoperative pain after cardiac surgery.
Postoperative pain management after cardiac surgery has been mainly based on parenteral opioids. However, because opioids have numerous side effects, coadministration of non-opioid analgesics has been introduced as a method of reducing opioid dose. In this prospective, randomized, double-blinded study, we evaluated the efficacy of propacetamol, an IV administered prodrug of acetaminophen (paracetamol), as an adjunctive analgesic after cardiac surgery. Seventy-nine patients scheduled for elective coronary artery bypass grafting were randomized to receive either propacetamol 2 g (n = 40) or placebo (n = 39) IV in 6-h intervals for 72 h. From the time of extubation, patients had access to an opioid (oxycodone) via a patient-controlled analgesia device. Pain was evaluated on a visual analog scale four times daily, whereas respiratory function tests (forced vital capacity, forced expiratory volume in 1 s, peak expiratory flow, and arterial blood gas measurements) were performed once a day. The prespecified primary efficacy variable (cumulative oxycodone consumption at the end of the 72-h postoperative period) was 123.5 mg (51.3 mg) (mean [SD]) in the propacetamol group and 141.8 mg (57.5 mg) in the placebo group (difference in mean, 18.3 mg = 13%; 95% confidence interval, 6.1-42.7 mg; P = 0.15). Pain scores did not differ between the groups at rest (P = 0.65) or during a deep breath (P = 0.72). The groups were also similar in terms of pulmonary function tests, postoperative bleeding, and hepatic function tests, and no significant differences were noted in the incidences of adverse effects. After completion of the study, apost hoc analysis was also performed analyzing the first 24 h as split into 6-h intervals. This analysis showed a significantly (P = 0.036) smaller consumption of oxycodone in the propacetamol group at 24 h (47.1 mg [20.7 mg] versus 57.9 mg [23.9 mg]; difference in mean, 10.8 mg; 95% confidence interval, 0.7-20.9 mg). In conclusion, propacetamol did not enhance opioid-based analgesia in coronary artery bypass grafting patients, nor did it decrease cumulative opioid consumption or reduce adverse effects within 3 days after surgery. However, post hoc analysis showed that oxycodone requirement was reduced within the first 24 h in the propacetamol group. ⋯ This is the first placebo-controlled study to investigate the efficacy of propacetamol as a complementary analgesic to opioids after cardiac surgery. Propacetamol did not enhance analgesia, nor did it decrease cumulative opioid consumption or reduce adverse effects in a dose of 2 g given every sixth hour for 3 days after surgery.
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Anesthesia and analgesia · Oct 2002
Comparative Study Clinical TrialPreload index: pulmonary artery occlusion pressure versus intrathoracic blood volume monitoring during lung transplantation.
In this study, during lung transplantation, we analyzed a conventional preload index, the pulmonary artery occlusion pressure (PAOP), and a new preload index, the intrathoracic blood volume index (ITBVI), derived from the single-indicator transpulmonary dilution technique (PiCCO System), with respect to stroke volume index (SVIpa). We also evaluated the relationships between changes (Delta) in ITBVI and PAOP and DeltaSVIpa during lung transplantation. The reproducibility and precision of all cardiac index measurements obtained with the transpulmonary single-indicator dilution technique (CIart) and with the pulmonary artery thermodilution technique (CIpa) were also determined. Measurements were made in 50 patients monitored with a pulmonary artery catheter and with a PiCCO System at six stages throughout the study. Changes in the variables were calculated by subtracting the first from the second measurement (Delta(1)) and so on (Delta(1) to Delta(5)). The linear correlation between ITBVI and SVIpa was significant (r(2)=0.41; P < 0.0001), whereas PAOP poorly correlated with SVIpa (r(2) = -0.01). Changes in ITBVI correlated with changes in SVIpa (Delta(1), r(2) = 0.30; Delta(2), r(2) = 0.57; Delta(4), r(2) = 0.26; and Delta(5), r(2) = 0.67), whereas PAOP failed. The mean bias between CIart and CIpa was 0.15 l. min(-1). m(-2) (1.37). In conclusion, ITBVI is a valid indicator of cardiac preload and may be superior to PAOP in patients undergoing lung transplantation. ⋯ The assessment of intrathoracic blood volume index (ITBVI) by the transpulmonary single-indicator technique is a useful tool in lung transplant patients, providing a valid index of cardiac preload that may be superior to pulmonary artery occlusion pressure. However, more prospective, randomized studies are necessary to evaluate the role and limitations of this technique.
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Anesthesia and analgesia · Oct 2002
A neurosteroid anesthetic, alphaxalone, inhibits nicotinic acetylcholine receptors in cultured bovine adrenal chromaffin cells.
Several lines of evidence suggest that nicotinic acetylcholine receptors (nAChRs) are a target of general anesthetics. Alphaxalone (5alpha-pregnan-3alpha-ol-11, 20-dion) is a neurosteroid, which was used clinically for anesthesia, but its effects on the function of nAChRs have not been well investigated. We examined the effects of alphaxalone on nAChRs in cultured bovine adrenal chromaffin cells. We studied the effects of alphaxalone on nicotine-induced increases in the cytosolic Ca(2+) concentration ([Ca(2+)](i)) and on membrane currents using Ca(2+)-imaging and whole-cell patch-clamp techniques, respectively, in these cells. We also examined the effects of alphaxalone on gamma-aminobutyric acid A receptors in the same cells and compared them with the effects on nAChRs. Alphaxalone (0.1-100 micro M) inhibited nicotine-induced [Ca(2+)](i) increases in a concentration-dependent manner. Alphaxalone inhibited high K(+)-induced [Ca(2+)](i) increases, but the inhibition was observed only at 100 micro M. In voltage-clamp experiments using negative holding potentials, alphaxalone (0.1-100 micro M) itself induced inward currents, which were abolished by the gamma-aminobutyric acid A receptor antagonist picrotoxin. Alphaxalone also inhibited nicotine-induced inward currents, and the inhibition was unaffected by picrotoxin. We conclude that alphaxalone, at anesthetic concentrations, inhibits nAChRs in adrenal chromaffin cells. Alphaxalone may affect the sympathetic and other nervous systems via inhibition of nAChRs. ⋯ Alphaxalone inhibits the function of nAChRs at clinically relevant concentrations in adrenal chromaffin cells. Thus, the present findings may provide some information for understanding the anesthetic mechanism of alphaxalone.