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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, METHODS, RESULTS. Meshes: Anesthesia, Anesthesia, Inhalation, Anesthesia, Intravenous, Anesthetics, Inhalation, Anesthetics, Intravenous, Animals, Atrasentan, Blood Loss, Surgical, Catecholamines, Dog Diseases, Dogs, Endothelin A Receptor Antagonists, Endothelin-1, Epinephrine, Female, Hemodynamics, Hemorrhage, Isoflurane, Norepinephrine, Piperidines, Pyrrolidines, Remifentanil, Time Factors, Vascular Resistance, Vasopressins, Xenon.
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Does endothelin receptor subtype A blockade affect the haemodynamic recovery from haemorrhage during xenon/remifentanil or isoflurane/remifentanil anaesthesia in dogs? Context: To test the compensatory role of endothelin-1 when acute blood loss is superimposed on anaesthesia, by characterizing the effect of systemic endothelin receptor subtype A (ET(A)) blockade on the haemodynamic and hormonal responses to haemorrhage in dogs anaesthetized with xenon/remifentanil (X/R) or isoflurane/remifentanil (I/R). Prospective experimental randomized controlled study. Six female Beagle dogs, 13.4 +/- 1.3 kg. Animals were anaesthetized with remifentanil 0.5 microg kg(-1) minute(-1) plus either 0.8% isoflurane (I/R) or 63% xenon (X/R), with and without (Control) the systemic intravenous endothelin receptor subtype A antagonist atrasentan (four groups, n = 6 each). After 60 minutes of baseline anaesthesia, the dogs were bled (20 mL kg(-1)) over 5 minutes and hypovolemia was maintained for 1 hour. Continuous haemodynamic monitoring was performed via femoral and pulmonary artery catheters; vasoactive hormones were measured before and after haemorrhage. In Controls, systemic vascular resistance (SVR), vasopressin and catecholamine plasma concentrations were higher with X/R than with I/R anaesthesia at pre-haemorrhage baseline. The peak increase after haemorrhage was higher during X/R than during I/R anaesthesia (SVR 7420 +/- 867 versus 5423 +/- 547 dyne seconds cm(-5); vasopressin 104 +/- 23 versus 44 +/- 6 pg mL(-1); epinephrine 2956 +/- 310 versus 177 +/- 99 pg mL(-1); norepinephrine 862 +/- 117 versus 195 +/- 33 pg mL(-1), p < 0.05). Haemorrhage reduced central venous pressure from 3 +/- 1 to 1 +/- 1 cm H(2)O (I/R, ns) and from 8 +/- 1 to 5 +/- 1 cm H(2)O (X/R, p < 0.05), but did not reduce mean arterial pressure, nor cardiac output. Atrasentan did not alter the haemodynamic and hormonal response to haemorrhage during either anaesthetic protocol.
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Selective ET(A) receptor blockade with atrasentan did not impair the haemodynamic and hormonal compensation of acute haemorrhage during X/R or I/R anaesthesia in dogs. Final Decision: no