Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Clinical TrialPlatelet-rich plasma sequestration, with therapeutic platelet yields, reduces allogeneic transfusion in complex cardiac surgery.
Platelet dysfunction is the most common cause of nonsurgical bleeding after cardiopulmonary bypass (CPB). We hypothesized that reinfusion of a therapeutic quantity of platelets sequestered before CPB would decrease the need for allogeneic platelet transfusion, as well as decrease bleeding and total allogeneic transfusion, in cardiac surgery patients at moderately high risk for bleeding. Fifty-five patients undergoing either reoperative coronary artery bypass (CABG) or combined CABG and valve replacement were randomized to control or platelet-rich plasma sequestration (pheresis) groups. All patients received intraoperative epsilon-aminocaproic acid infusions. There was no significant difference between groups with respect to preoperative characteristics, duration of CPB, or target postoperative hematocrit. Mean platelet yields were 6.2 +/- 2.1 units (3.1 x 10(11) platelets). Mean pheresis time was 44 min. Allogeneic platelets (range = 6-12 units) were transfused to 28% of control patients, compared with 0% of pheresis patients (P < 0.01). Allogeneic packed red blood cells were transfused to 45% of control patients (1.2 units per patient) versus 31% of pheresis patients (0. 7 unit per patient) (P = 0.35). Total allogeneic units transfused were significantly reduced in the pheresis group (P < 0.02). Mediastinal chest tube drainage was not significantly decreased in the pheresis group. In this prospective, randomized study, therapeutic platelet yields were obtained before CPB. In contrast with recent studies with low platelet yields, these data support the conclusion that platelet-rich plasma sequestration is effective in reducing allogeneic platelet transfusions and total allogeneic units transfused in cardiac surgery patients at moderately high risk for post-CPB coagulopathy and bleeding. ⋯ Transfusion of allogeneic blood products, including platelets, is common during complex cardiac surgical procedures. In the present prospective, randomized study, a significant reduction in allogeneic platelet transfusion and total allogeneic units transfused was observed after the reinfusion of a therapeutic quantity of autologous platelets sequestered before cardiopulmonary bypass.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Clinical TrialThe inhibition of epidural morphine-induced pruritus by epidural droperidol.
IV droperidol inhibits epidural morphine-induced pruritus, but this effect disappears when the dose is increased from 2.5 to 5.0 mg. This study was performed to determine whether epidural droperidol would have a similar effect. In this double-blinded study, we enrolled 140 patients undergoing Cesarean delivery under epidural anesthesia who were randomly allocated to four groups. Anesthesia consisted of 150 mg of 0.5% bupivacaine with 1:200,000 epinephrine, with 2 mg of morphine and 0.0, 1.25, 2.5, or 5.0 mg of droperidol (Groups 1 to 4). During the postoperative period, patients were assessed for pruritus (absent, mild, moderate, or severe) and other untoward symptoms. The chi(2) test was used to compare the incidence of the side effects. For the analysis of pruritus, we used the Mantel-Haenszel test for linear association. Droperidol induced a dose-related reduction in the incidence of pruritus (P < 0.001). This reduction was independent of the incidence of somnolence, which increased with droperidol dose (P < 0.05 when the incidence of somnolence in Groups 1 and 4 was compared). We conclude that droperidol, in doses up to 5 mg epidurally, induces a dose-related reduction in the incidence of pruritus without inducing significant side effects. ⋯ Epidural morphine is effective for pain control but yields some side effects, including pruritus, that can be severe. Studying patients undergoing Cesarean delivery, we found a dose-related reduction in the incidence of pruritus using epidural droperidol.
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Anesthesia and analgesia · Mar 2000
No implicit memory for stories played during isoflurane/alfentanil/nitrous oxide anesthesia: a reading speed measurement.
Implicit memory of intraoperatively presented stories was recently detected by using the reading speed paradigm during propofol-alfentanil-nitrous oxide anesthesia. Our main goal was to evaluate the reading speed test procedure under another anesthetic regimen, i.e., isoflurane combined with nitrous oxide and alfentanil-infusion. In both experiments, patients were premedicated with oral midazolam. In a previous experiment, patients postoperatively read "old" stories that had been presented during anesthesia quicker compared with "new," unpresented stories. The same study design and test material as in the previous experiment were used. One of two audio tapes with two short stories was played randomly to patients during lumbar disk surgery and to awake controls. Approximately 7 h later, a structured interview and the reading speed test were used to determine whether the participants had any explicit or implicit memories of the presented stories. The results of 30 patients and 30 controls were calculated. Whereas the control participants showed an intact explicit and implicit memory of the previously presented material, no such effect was found in the anesthetized patients. The present experiment shows that changing the main anesthetic in otherwise equal study conditions, i. e., propofol to isoflurane (end-expiratory 0.7%), implicit memory is abolished in anesthetized patients. ⋯ We showed that implicit memory during general anesthesia can be abolished by changing the hypnotic anesthetic. Increased postoperative reading speed for stories presented during propofol-alfentanil-nitrous oxide anesthesia was shown in a previous experiment, but not in our study using isoflurane for balanced anesthesia.
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Anesthesia and analgesia · Mar 2000
The visual analog scale allows effective measurement of preoperative anxiety and detection of patients' anesthetic concerns.
The advent of managed care, reduction of costs, and advances in medical technology place increasing demands on anesthesiologists. Preoperative anxiety may go unnoticed in an environment that stresses increased productivity. The present study compares different methods for measuring preoperative anxiety, identifies certain patient characteristics that predispose to high anxiety, and describes the quantity and quality of anxiety that patients experience preoperatively. Seven hundred thirty-four patients participated in the study. We assessed aspects of anxiety by means of visual analog scales (VAS) and the State Anxiety Score of the Spielberger State-Trait Anxiety Inventory (STAI). The mean STAI anxiety score was 39 +/- 1 (n = 486) and the mean VAS for fear of anesthesia was 29 +/- 1 (n = 539). Patients feared surgery significantly more than anesthesia (P < 0.001). The VAS measuring fear of anesthesia correlated well with the STAI score (r = 0.55; P < 0.01). Young patients, female patients, and patients with no previous anesthetic experience or a previous negative anesthetic experience had higher anxiety scores. Patients worried most about the waiting period preceding surgery and were least concerned about possible awareness intraoperatively. Factor analysis of various anxiety items showed three distinct dimensions of fear: 1) the fear of the unknown 2) the fear of feeling ill, and 3) the fear for one's life. Among these dimensions, fear of the unknown correlated highest with the anxiety measuring techniques STAI and VAS. The simple VAS proved to be a useful and valid measure of preoperative anxiety. ⋯ The study of qualitative aspects of anxiety reveals three distinct dimensions of preoperative fear: fear of the unknown, fear of feeling ill, and fear for one's life. Groups of patients with a higher degree of preoperative anxiety and their specific anesthetic concerns can be identified using the visual analog scale.