Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Comparative Study Clinical TrialHydroxyethyl starch (HES) 130/0.4 provides larger and faster increases in tissue oxygen tension in comparison with prehemodilution values than HES 70/0.5 or HES 200/0.5 in volunteers undergoing acute normovolemic hemodilution.
Stable hemodynamics and improved rheology are important effects of hemodilution with hydroxyethyl starch (HES) infusions. One clinical indicator of improved rheology is increased tissue oxygen tension (tpO(2)). In this prospective, randomized, double-blinded, crossover study, we examined the effects of acute normovolemic hemodilution with HES 130/0.4 on hemodynamics and skeletal muscle tpO(2) in comparison with conventional HES solutions. Twelve healthy volunteers were randomly enrolled in each group. At an interval of >8 days, volunteers donated 18% of their calculated blood volume within 30 min and randomly received 6% HES 130/0.4, 6% HES 70/0.5, or 6% HES 200/0.5 (crossover design) in a 1:1.2 ratio to their blood loss. Hemodynamic variables, tpO(2) in the quadriceps muscle, hematocrit, plasmatic HES concentrations, plasma viscosity, colloid osmotic pressures, and platelet aggregation were measured until 6 h after the infusion of HES. No differences were found among groups with respect to changes of hemodynamics, hematocrit, or platelet aggregation. With HES 200, colloid osmotic pressures and plasma viscosities were larger than after HES 70 (P < 0.05). HES 130 in comparison with HES 70 and 200 caused the fastest (30 min versus 90 min and 150 min after hemodilution; P < 0.05) and largest increase of tpO(2) in comparison to baseline (+93% versus +33% and 40%; P < 0.05). In healthy volunteers undergoing acute normovolemic hemodilution, the newly designed HES 130/0.4 showed a more pronounced and earlier increase of skeletal muscle tpO(2) in comparison with prehemodilution values than HES 70/0.5 or 200/0.5. ⋯ The effects of three different hydroxyethyl starch (HES) solutions on hemodynamics, rheology, and skeletal muscle tissue tension after acute normovolemic hemodilution were examined in awake volunteers. With HES 130/0.4, increases of tissue oxygen tension in comparison to baseline were larger and more rapid than with HES 70/0.5 or HES 200/0.5.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialThe effect of remifentanil on seizure duration and acute hemodynamic responses to electroconvulsive therapy.
We designed this prospective, randomized, double-blinded, placebo-controlled, crossover study to evaluate the effect of different doses of remifentanil on the acute hemodynamic response and duration of seizure activity after a standardized electroconvulsive therapy (ECT) stimulus. Twenty consenting patients with major depressive disorders receiving maintenance ECT participated in this study. Eighty ECT treatments were evaluated. All patients were premedicated with glycopyrrolate 0.2 mg IV, unconsciousness was induced with methohexital 1 mg/kg IV, and muscle paralysis was produced with succinylcholine 1.2 mg/kg IV. Subsequently, patients received 1 of 3 different doses of remifentanil 25, 50, and 100 microg or saline (control) in a random sequence immediately after methohexital at 4 consecutive ECT treatments. Labetalol, in 5-mg IV boluses, was used as a rescue antihypertensive medication. A fixed suprathreshold electrical stimulus was administered to elicit a seizure, and the times from the stimulus to the cessation of the motor and electroencephalographic (EEG) seizure activity were noted. Pre- and post-ECT blood pressure values were significantly decreased in the 100- microg remifentanil group compared with the control group. The durations of motor (38 +/- 9 s to 43 +/- 15 s) and EEG (55 +/- 29 s to 60 +/- 21 s) seizure activity were not significantly different among the four groups. Similarly, recovery times to eye opening, obeying commands, and discharge from the recovery room did not differ among the four study groups. The requirement for labetalol after ECT was nonsignificantly decreased in the remifentanil groups. In conclusion, remifentanil 100 microg IV attenuated the acute hemodynamic response to ECT. Furthermore, remifentanil had no adverse effect on the duration of ECT-induced seizure activity. Finally, adjunctive use of remifentanil did not prolong recovery times or increase post-ECT side effects. ⋯ Remifentanil (100 microg IV) attenuated the acute hemodynamic response after electroconvulsive therapy (ECT) without adversely affecting the length of the ECT-induced seizure activity or prolonging recovery times.
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Comparative Study Clinical TrialRopivacaine 0.15% plus sufentanil 0.5 microg/mL and ropivacaine 0.10% plus sufentanil 0.5 microg/mL are equivalent for patient-controlled epidural analgesia during labor.
We compared the administration of 0.15% ropivacaine plus 0.5 microg/mL of sufentanil with that of 0.10% ropivacaine plus 0.5 microg/mL of sufentanil for labor analgesia with patient-controlled epidural analgesia (PCEA) to determine whether a decreased concentration of ropivacaine could produce equally effective analgesia. One-hundred-thirty healthy pregnant women at term were randomized in a double-blinded fashion. The PCEA settings were as follows: 12-mL initial bolus, 5-mL bolus dose, 5-min lockout interval, and 10 mL/h basal infusion. Patient demographics and labor characteristics were comparable in both groups. No differences were observed for pain scores, maternal satisfaction, volume of anesthetic solution administered, number of boluses requested and delivered, need for supplemental boluses, mode of delivery, motor block, side effects, or Apgar scores. Patients in the 0.10% ropivacaine group used significantly less drug than those in the 0.15% group (mean, 57 mg; 95% confidence interval, 50.5-63.5 mg; versus mean, 88.0 mg; 95% confidence interval, 74.4-93.3 mg, respectively; P < 0.0001). Ropivacaine 0.10% plus 0.5 microg/mL of sufentanil administered via PCEA for labor analgesia is equally effective as ropivacaine 0.15% plus 0.5 microg/mL of sufentanil, with a 30% local anesthetic-sparing effect and a 40% reduction in cost. However, this reduction in local anesthetic is not associated with a decrease in the incidence of motor block, side effects, or instrumental deliveries. ⋯ Ropivacaine 0.10% plus 0.5 microg/mL of sufentanil given via patient-controlled epidural anesthesia for labor analgesia is equally as effective as ropivacaine 0.15% plus 0.5 microg/mL of sufentanil, with a 30% local anesthetic-sparing effect and a 40% reduction in cost. This reduction in ropivacaine concentration is not associated with a decrease in the incidence of motor block, side effects, or instrumental deliveries.
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Anesthesia and analgesia · Apr 2003
Parental intervention choices for children undergoing repeated surgeries.
No studies have examined parental preference for a preoperative intervention in healthy children undergoing subsequent surgeries. We collected data prospectively from 83 children who previously underwent surgery and were part of an investigation by our study group, then returned for a subsequent surgery. At the initial surgery, children were assigned (no parental intervention) to receive oral midazolam (n = 13), or parental presence during the induction of anesthesia (PPIA, n = 27), or PPIA + midazolam (n = 10) or no intervention (n = 33). At a subsequent surgery, parents chose the preoperative intervention. We found that >80% of all parents chose PPIA (with or without midazolam) at the subsequent surgery regardless of the intervention they received previously. Of parents whose children received PPIA at the initial surgery, 70% chose PPIA again. In contrast, only 23% of the patients who received midazolam at the initial surgery requested midazolam at the subsequent surgery and only 15% of the patients who received no intervention at the initial surgery requested no intervention at the subsequent surgery. All parents of very anxious children at the initial surgery chose some intervention at the subsequent surgery (P = 0.022). Parents of children who underwent a subsequent surgery preferred PPIA regardless of any previous intervention. Also, parents' intervention preferences at the subsequent surgery were influenced by children's anxiety at the initial surgery. ⋯ Parents of children who undergo a subsequent surgery prefer to be present during the induction of anesthesia regardless of whether the child was medicated or had parents present or did not receive anything at the initial surgery. Also, parents' preference for medication or parental presence at the subsequent surgery was influenced by the child's anxiety at the initial surgery.
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Anesthesia and analgesia · Apr 2003
Sevoflurane exposure generates superoxide but leads to decreased superoxide during ischemia and reperfusion in isolated hearts.
Reactive oxygen species (ROS) are largely responsible for cardiac injury consequent to ischemia and reperfusion, but, paradoxically, there is evidence suggesting that anesthetics induce preconditioning (APC) by generating ROS. We hypothesized that sevoflurane generates the ROS superoxide (O(2)(.-)), that APC attenuates O(2)(.-) formation during ischemia, and that this attenuation is reversed by bracketing APC with the O(2)(.-) scavenger manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (MnTBAP) or the putative mitochondrial adenosine triphosphate-sensitive potassium (mK(ATP)) channel blocker 5-hydroxydecanoate (5-HD). O(2)(.-) was measured continuously in guinea pig hearts by using dihydroethidium. Sevoflurane was administered alone (APC), with MnTBAP, or with 5-HD before 30 min of ischemia and 120 min of reperfusion. Control hearts underwent no pretreatment. Sevoflurane directly increased O(2)(.-); this was blocked by MnTBAP but not by 5-HD. O(2)(.-) increased during ischemia and during reperfusion. These increases in O(2)(.-) were attenuated in the APC group, but this was prevented by MnTBAP or 5-HD. We conclude that sevoflurane directly induces O(2)(.-) formation but that O(2)(.-) formation is decreased during subsequent ischemia and reperfusion. The former effect appears independent of mK(ATP) channels, but not the latter. Our study indicates that APC is initiated by ROS that in turn cause mK(ATP) channel opening. Although there appears to be a paradoxical role for ROS in triggering and mediating APC, a possible mechanism is offered. ⋯ Reactive oxygen species (ROS) are implicated in triggering anesthetic preconditioning (APC). The ROS superoxide (O(2)(.-)) was measured continuously in guinea pig isolated hearts. Sevoflurane directly increased O(2)(.-) but led to attenuated O(2)(.-) formation during ischemia. This demonstrates triggering of APC by ROS and clarifies the mechanism of cardioprotection during ischemia.