Acta anaesthesiologica Scandinavica
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We have used hypothermia successfully in patients with acute respiratory failure after lung transplantation. However, we have observed that dopamine may cause a substantial decrease in mean arterial pressure (MAP) in hypothermic subjects. Furthermore, a dopamine-induced increase in pulmonary vascular resistance (PVR) has been reported in the literature, and this could aggravate the increase in PVR which is often seen both in the early postoperative phase after lung transplantation, and during hypothermia. We thus hypothesized that dopamine would decrease MAP and increase PVR in hypothermic lung-transplanted subjects. ⋯ The results suggest that dopamine may be used to increase cardiac output after lung transplantation in moderate hypothermia as well as in normothermia, but one should be aware that dopamine may cause a substantial decrease in blood pressure, depending on the prevailing hemodynamic conditions at the start of its administration.
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Acta Anaesthesiol Scand · Aug 1999
Comparative StudyCaffeine- or halothane-induced contractures of masseter muscle are similar to those of vastus muscle in normal humans.
Skinned fibers from normal human masseter muscle have greater caffeine and calcium sensitivity than skinned fibers from vastus muscle. We examined sensitivity to caffeine and halothane in fresh, cut muscle bundles (non-skinned) from human masseter muscle. ⋯ Contracture responses of intact cut masseter and vastus bundles (non-skinned) do not differ with respect to caffeine and halothane. Responses of skinned fibers might demonstrate greater sensitivity under certain conditions, but they do not reflect those of intact cut bundles.
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Acta Anaesthesiol Scand · Aug 1999
Intrathecal co-administration of NMDA antagonist and NK-1 antagonist reduces MAC of isoflurane in rats.
Intravenous administration of N-methyl-D-aspartate (NMDA) receptor antagonists and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor antagonists reportedly reduce the minimum alveolar anaesthetic concentration (MAC) for inhalation anaesthetics. If pain perception can be prevented by the intrathecal administration of antinociceptive receptor antagonists, these agents may reduce the requirements for inhalation anaesthetics. We studied the effect of intrathecal administration of an AMPA/kainate receptor antagonist, a metabotropic glutamate (mGlu) receptor antagonist and co-administration of NMDA and a neurokinin-1(NK-1) receptor antagonist drugs at low doses on the MAC. ⋯ The NMDA receptor and the NK-1 receptor are important determinants of the MAC of isoflurane, exerting this influence by inhibition of pain transmission in the spinal cord, while mGlu and AMPA receptors have no effect on the MAC of isoflurane.