Journal of anesthesia
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Journal of anesthesia · Oct 1993
Naloxone and flumazenil fail to antagonize the isoflurane-induced suppression of dorsal horn neurons in cats.
Effects of naloxone and flumazenil on isoflurane activities were examined on dorsal horn neurons in cats. Isoflurane suppressed bradykinin-induced nociceptive responses in transected feline spinal cords. The bradykinin-induced neuronal firing rates were significantly suppressed by 60.0%, 35.3% and 32.2% at 10, 20 and 30 min after isoflurane administration, respectively. ⋯ The suppressive effects of isoflurane were not reversed by naloxone (0.2 mg.kg(-1), i.v.). Similarly, the benzodiazepine antagonist, flumazenil (0.2 mg.kg(-1), i.v.), did not affect the suppressive effects of isoflurane. Failure of naloxone and flumazenil to reverse the suppressive effects of isoflurane suggests that isoflurane interacts with neither opioid nor benzodiazepine receptors in producing its suppressive action on nociceptive responses in dorsal horn neurons of the feline spinal cord.
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Journal of anesthesia · Jul 1993
Differences in the assessment of postoperative pain when evaluated by patients and doctors.
This study was undertaken to compare the assessment of pain intensity by 59 patients and by their doctors according to a visual analogue scale (VAS) at rest and when coughing at 5 and 20 hr after major abdominal surgery. The rating given by the patients, who received epidural analgesia to relieve postoperative pain, was significantly above, and moreover, significantly correlated with that given by the doctors at any time or under any condition of the assessment. ⋯ Our findings indicate that the assessment of postoperative pain may be associated with some unreliability, especially during early periods, when using the subjective or objective-rated VAS at rest separately, and thus requires the combined use or the concomitant use of the VAS when coughing. Substitutional use of the objective-rated VAS for the subjective-rated VAS is not advised.
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Journal of anesthesia · Jul 1993
Changes in venous capacitance during prostaglandin E1-induced hypotension; comparisons with trinitroglycerin.
The purpose of this study was to examine the effects of prostaglandin E1 (PGE1) on venous capacitance during controlled hypotension. Trinitroglycerin (TNG) was used as a control agent. In rats anesthetized with ketamine, mean arterial pressure was lowered to 70 mmHg and subsequently 50 mmHg by intravenous infusion of PGE1 or TNG. ⋯ The decrease in MCFP by PGE1 at mean arterial pressure of 70 mmHg was not significantly different from TNG. However, the decrease in MCFP by PGE1 at mean arterial pressure of 50 mmHg was significantly less than that by TNG. The results suggest that the venous capacitance may be increased by PGE1 to a similar degree with TNG at doses to produce a comparable level of moderate hypotension, but the increase in venous capacitance may be less in PGE1 than TNG at doses to produce deep hypotension.
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Journal of anesthesia · Jan 1993
Modification of hepatic protein kinase C with phorbol myristate acetate and staurosporine alters hemodynamics in the perfused rat liver.
Activation of protein kinase C (PKC) has been implicated in the pathogenesis of endotoxicosis and severe sepsis. Since hepatic blood flow and metabolism have been known to be altered in endotoxicosis and sepsis, we studied the hemodynamic effect of PKC modulation with phorbol 12-myristate 13-acetate (PMA) and staurosporine (St) on the perfused rat liver. The liver was isolated from overnight-fasted male Sprague-Dawley rats and placed in a recirculating perfusion apparatus. ⋯ Pretreatment with St significantly attenuated the flow reduction by PMA. St significantly suppressed the flow reductions by 4 x 10(-6) M of prostaglandin E2 and D2. These results suggest that the PKC inside the liver may play an important role in the regulation of hepatic blood flow during endotoxicosis and sepsis.
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Journal of anesthesia · Jan 1993
Sustained effects of plasma norepinephrine levels on femoral-radial pressure gradient after cardiopulmonary bypass.
In order to determine the influence of the sympathetic nervous system upon the femoral-radial artery pressure gradient after cardiopulmonary bypass (CPB), we examined plasma norepinephrine levels in 34 adult male patients undergoing coronary artery bypass grafting. Cardiovascular parameters, including systolic arterial pressure, mean arterial pressure, cardiac index (CI), systemic vascular resistance index (SVRI), pulmonary artery pressure (PAP), hemoglobin (Hb) and peak dP/dt of radial and femoral artery pressures were measured after sternotomy, and immediately after the discontinuation of CPB and 90 min after CPB. Plasma norepinephrine levels were measured after sternotomy, after aortic declamping and 90 min after CPB. ⋯ Although there was no significant difference in Hb or PAP of 90 min after CPB in Groups A and B, the following values, listed in the order of A to B, were obtained; CI, 2.79 +/- 0.10 versus 3.46 +/- 0.16 l.min(-1).m(-2) (P < 0.01); mean radial artery pressure (MRP), 58.7 +/- 2.4 versus 65.1 +/- 1.8 mmHg (P < 0.05); peak dP/dt of radial artery pressure, 568 +/- 64 versus 1026 +/- 61 mmHg.sec(-1) (P < 0.001); and plasma norepinephrine concentration, 1.81 +/- 0.25 versus 0.98 +/- 0.10 ng.ml(-1) (P < 0.01), which were statistically significant. The higher femoral-radial artery pressure gradient after CPB was observed in patients with both a longer CPB time and a higher plasma norepinephrine concentration. These results suggest that a marked constriction of peripheral arteries might have produced a damped transmission of the pressure pulse to the radial artery.