Articles: general-anesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
The haemodynamic effects of bronchoscopy. Comparison of propofol and thiopentone with and without alfentanil pretreatment.
The haemodynamic response to bronchoscopy under general anaesthesia was investigated. Forty patients were allocated at random to receive either thiopentone or propofol; half the patients in each group received in addition 18 micrograms/kg of alfentanil one minute before induction of anaesthesia. The heart rate, noninvasive blood pressure and Holter ECG was monitored in all patients. ⋯ No significant haemodynamic changes were seen in either of the groups which received propofol. ST segment changes on subsequent Holter analysis were seen in four patients, but there were no significant differences between the groups. Anaesthesia with propofol alone provides adequate haemodynamic stability for bronchoscopy and the addition is superfluous.
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Randomized Controlled Trial Clinical Trial
Effect of ketanserin on intraoperative blood loss during total hip arthroplasty in elderly patients under general anaesthesia.
We have studied the effect of ketanserin, a selective serotonin S2-receptor antagonist, on surgical bleeding in a double-blind, placebo-controlled study in elderly patients undergoing total hip arthroplasty. One group of patients (n = 9) received ketanserin 10 mg i.v. followed by an infusion of 0.075 mg kg-1 h-1. The second group (n = 8) received placebo. ⋯ In the ketanserin group, mean arterial pressures tended to be less than in the placebo group. Reductions in central venous pressure were similar in both groups. There were no complications in relation to the use of ketanserin.
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To evaluate the possible interaction between clonidine and ephedrine, the authors studied hemodynamic responses to intravenous ephedrine in 80 patients who received either clonidine pre-anesthetic medication of approximately 5 micrograms.kg-1 orally (n = 40) or no medication (n = 40). The patients were studied while they were either awake (n = 40) or anesthetized with enflurane and nitrous oxide in oxygen (n = 40). ⋯ The enhanced pressor responses to ephedrine observed in both awake and anesthetized patients in the presence of clonidine may be attributed to increased catecholamine storage at sympathetic nerve endings due to clonidine, enhanced sensitivity of tissue receptors to which ephedrine binds, potentiation of alpha-adrenoceptor mediated vasoconstriction of both agents, or all of these. It is concluded that oral clonidine preanesthetic medication of 5 micrograms.kg-1 does augment rather than attenuate the pressor responses to intravenous ephedrine in patients both prior to and during general anesthesia.
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Comparative Study
The accuracy of Finapres noninvasive mean arterial pressure measurements in anesthetized patients.
The Finapres (FIN) is a new noninvasive blood pressure monitor that provides continuous arterial waveform display with the use of a finger cuff. The authors assessed the accuracy of FIN mean arterial pressure (MAP) measurements relative to simultaneous direct radial arterial pressures in 20 patients undergoing general anesthesia for major elective surgery. Data were collected digitally with the use of RS-232 communications over a total of 16.2 h. ⋯ However, 32.3 +/- 6.2% of all MAP comparisons differed by greater than +/- 10 mmHg, and 5.0 +/- 1.1% differed by greater than +/- 20 mmHg. Moreover, there was an average of one episode every 2 patient-hours when the FIN MAP differed by greater than +/- 20 mmHg for more than 1 min. Although the MAP measured by FIN accurately reflected direct MAPs most of the time, there were occasional discrepancies of different magnitude such that clinical usefulness may be limited in patients in whom continuous accurate blood pressure measurements are essential.