Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2001
Randomized Controlled Trial Comparative Study Clinical TrialA randomized, double-blinded comparison of intrathecal morphine, sufentanil and their combination versus IV morphine patient-controlled analgesia for postthoracotomy pain.
We compared the analgesic effect of lumbar intrathecal (IT) 0.5 mg morphine (Group M, n = 10), 50 microg sufentanil (Group S, n = 10), and their combination (Group S-M, n = 10) given before general anesthesia and patient-controlled analgesia with IV morphine (Group C, n = 19) in a randomized, double-blinded study performed in patients undergoing thoracotomy. Pain visual analog scale (VAS) and morphine consumption were assessed for 24 h. In Group S-M the number of patients initially titrated with IV morphine was less than in group C (30 vs 84%, P < 0.05). Morphine requirement was higher in Group C (71 +/- 30 mg) than in Groups S (46 +/- 34 mg, P < 0.05), M (38 +/- 31 mg, P < 0.05) and S-M (23 +/- 16 mg, P < 0.01). VAS scores were significantly decreased during the first 0-11 postoperative h at rest and during the first 0-8 postoperative h on coughing in Groups M and S-M rather than in Group C. The incidence of side effects was infrequent except for urinary retention. Preoperative IT morphine or combined sufentanil and morphine could be given as a booster to achieve rapidly effective analgesia in the immediate postoperative period. ⋯ As compared with IV patient-controlled analgesia, intrathecal morphine or combined sufentanil and morphine provided superior postoperative pain relief both at rest (11 h) and on coughing (8 h) than did IV patient-controlled analgesia morphine alone. IV morphine requirement was decreased during the first postoperative day after posterolateral thoracotomy.
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Anesthesia and analgesia · Jan 2001
Clinical TrialVideo imaging to assess neuromuscular blockade at the larynx.
We describe video imaging as a technique for assessing neuromuscular blockade at the larynx. We sought to determine the stability and reproducibility of this technique and to compare the effect of succinylcholine at the adductor pollicis and the larynx. Ten patients were studied. Anesthesia was induced and maintained with propofol. The recurrent laryngeal nerve was stimulated superficially and movements of the vocal cords were recorded on videotape by using a fiberoptic bronchoscope passed via a laryngeal mask airway. Neuromuscular function was recorded at the adductor pollicis by using a mechanomyograph. Twenty images of the vocal cords were examined repeatedly by one investigator and by ten independent observers. The mean difference between the two sets of observations was 0.86 degrees with a correlation coefficient (r) of 0.997. For 3 min before the administration of relaxant the coefficient of variation in the cord movement during supramaximal stimulation ranged from 1%-4% (median 2.7%). After the administration of succinylcholine 1 mg. kg(-1) the times to loss of T1 at the larynx and hand were 63 +/- 15 s and 63 +/- 12 s respectively. Times to 25% recovery were 215 +/- 36 s at the larynx and 436 +/- 74 s at the hand and times to 75% recovery were 285 +/- 55 s and 525 +/- 85 s respectively. These results indicate that video imaging may be a useful research technique for estimating neuromuscular blockade at the larynx and that the time to onset of succinylcholine at the larynx is similar to that at the hand, whereas the duration of blockade is significantly shorter at the larynx. ⋯ Assessment of neuromuscular blockade at the larynx is possible by using a video imaging technique. By using this technique, the time to onset of neuromuscular blockade at the larynx is similar to that at the hand after the administration of succinylcholine; this finding is different from previously published data obtained by using a cuff pressure measurement technique.
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Anesthesia and analgesia · Jan 2001
Randomized Controlled Trial Comparative Study Clinical TrialShould the angiotensin II antagonists be discontinued before surgery?
Angiotensin II antagonists (AIIA) are part of a new rational treatment of hypertension. Because adverse circulatory effects during anesthesia can occur in patients chronically treated with angiotensin-converting enzyme inhibitors, some clinicians discontinue them at least 24 h before operation. No data are available concerning AIIA administration in patients scheduled for vascular surgery performed under general anesthesia. The aim of this prospective randomized study was to compare hemodynamics during induction of anesthesia in patients chronically treated with AIIA and those of patients not receiving this drug on the morning before operation. Thirty-seven patients chronically treated with AIIA for hypertension were randomly assigned to two groups: Group I: AIIA discontinued on the day before surgery (n = 18); Group II: AIIA given 1 h before anesthesia (n = 19). Patients received sufentanil 0.4 microg/kg, propofol 1.5 mg/kg, and atracurium 0.5 mg/kg. During the procedure, the anesthesiologist was required to maintain systolic blood pressure and heart rate within 30% of baseline values using intravascular fluid administration and vasoconstric- tors (e.g. , ephedrine, phenylephrine, or terlipressin). Hemodynamic variables were recorded each 1 min. Hemodynamic study ended at incision. The number and duration of hemodynamic events were collected, and total doses of vasoactive drugs were noted in each group. Systolic arterial pressure was significantly decreased in Group II at 5, 15 and 23 min after induction of anesthesia (*P < 0.05). In this group, the decrease in systolic arterial pressure was associated with more frequent episodes of hypotension (AIIA withdrawn: 1 +/- 1; AIIA given: 2 +/- 1; P < 0.01), with a larger number of patients developing at least 1 episode of hypotension (AIIA withdrawn: 12; AIIA given: 19; P < 0.01), and a longer duration of an episode of hypotension (AIIA withdrawn: 3 +/- 4 min; AIIA given: 8 +/- 7 min; P < 0.01), and an increased need for vasoactive drugs. In conclusion, blockade of the renin-angiotensin system increases the potential hypotensive effect of anesthetic induction. A severe hypotensive episode, requiring vasoconstrictor treatment, occurs after induction of general anesthesia in patients chronically treated with AIIA. Recommendations to discontinue AIIA drugs on the day before the surgery may be justified. ⋯ This prospective randomized study demonstrated that more severe hypotensive episodes, requiring vasoconstrictor treatment, occur after induction of general anesthesia in patients chronically treated with AIIA and receiving this drug on the morning before operation, in comparison with those in whom AIIA were discontinued on the day before operation. Recommendations to discontinue these drugs on the day before the surgery may be justified.
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Anesthesia and analgesia · Jan 2001
Randomized Controlled Trial Clinical TrialProfile soft-seal cuff, a new endotracheal tube, effectively inhibits an increase in the cuff pressure through high compliance rather than low diffusion of nitrous oxide.
We assessed the nitrous oxide (N(2)O) gas-barrier properties of a new endotracheal tube cuff, the Profile Soft-Seal Cuff (PSSC) (Sims Portex, Kent, UK). The tracheas of randomly selected patients were intubated with the Trachelon (Terumo, Tokyo, Japan), Profile Cuff (PC) (Sims Portex), or PSSC (n = 15 for each) endotracheal tube. Cuffs were inflated with air, and intracuff pressure was measured during anesthesia with 67% N(2)O. ⋯ The incidence of postoperative sore throat in the Trachelon group was significantly higher than in the other two groups. In summary, the PSSC effectively inhibits an increase in cuff pressure during anesthesia with N(2)O. The underlying mechanism is probably the higher compliance of the thinner cuff, rather than a reduction in N(2)O diffusion into the cuff.
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Anesthesia and analgesia · Jan 2001
Randomized Controlled Trial Clinical TrialThe clinical relevance of embolic events detected by transesophageal echocardiography during cemented total hip arthroplasty: a randomized clinical trial.
The first aim of this prospective clinical study was to characterize the relationship between embolic events observed during cemented total hip arthroplasty using transesophageal echocardiography (TEE), and changes in cardiopulmonary function. The second aim was to assess the efficiency of a modified cementing technique that was developed to reduce the risk of embolism. The modification consists in a vacuum drainage placed in the proximal femur to reduce the increase of intramedullary pressure during insertion of the prosthesis. One hundred twenty patients were randomized into two groups. Group 1 received a total hip arthroplasty cemented conventionally, whereas Group 2 was cemented with the modified technique. Continuous TEE, hemodynamic monitoring, and blood gas analysis were done during the perioperative period. Severe embolic events were imaged during the insertion of the femoral component and the reduction of the hip joint. Embolism occurred in 93.3% of patients operated on with the conventional cementing technique, compared with 13.3% of patients operated on with the modified technique (P < 0.05). Intraoperative shunt values during insertion of the femoral component increased from 8.2% to 10.3% (P < 0.05) in Group 1 patients, whereas there was no significant change in Group 2 patients. We observed no clinical signs of fat embolism syndrome in any study patient. The results of the study indicate that embolic events observed using TEE can cause increased pulmonary shunt values during hip arthroplasty, especially in patients with systemic disease (ASA physical status III). The modified surgical technique effectively reduced the incidence of embolization during cemented hip arthroplasty. ⋯ Use of conventional cementing techniques is associated with echocardiographic evidence of embolism in 93% of patients and with a significant increase in pulmonary shunting. The incidence of embolism and change in shunting are reduced with a modified cementing technique that limits increases in intramedullary pressure.