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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, RESULTS. Meshes: Analgesics, Opioid, Anesthesia, Intravenous, Anesthetics, Intravenous, Animals, Blood Pressure, Cardiac Output, Cardiac Tamponade, Cardiotonic Agents, Dobutamine, Drug Combinations, Electroencephalography, Hypnotics and Sedatives, Monitoring, Intraoperative, Piperidines, Propofol, Remifentanil, Swine.
user
Does bIS response to tamponade and dobutamine in swine vary with hypnotic/opiate ratio? Context: This study in swine assessed BIS stability in response to decreases and increases in cardiac output under two propofol/remifentanil dosage combinations, both producing the same depth of surgical anaesthesia. Eight anaesthetized-paralyzed ventilated adult swine were studied using a random-order cross-over design. Four received a P low/R high combination (P, 8.4+/-0.9 mg/kg/h; and R, 0.54+/-0.02 microg/kg/min) and then a P high/R low combination (P, 26.7+/-2.1mg/kg/h; and R, 0.34+/-0.01 microg/kg/min). The other four had these two combinations in the reverse order. Under each P/R combination, and after a 60-minutes steady state, a 15-minute stable cardiac tamponade was induced by intrapericardial gelatine infusion. Then, after returning to pre tamponade condition, a 15 minutes period with dobutamine was allowed. Tamponade induced falls in average mean arterial pressure (MAP) (from 79+/-18 to 47+/-9 mm Hg; p<0.05) and cardiac output (Qc) (from 1.90+/-0.46 l/min to 1.20+/-0.38 l/min, p<0.05). Conversely, dobutamine increased both MAP and Qc (p<0.05). During each type of hemodynamic challenges, changes in anaesthesia depth as assessed by BIS differed dramatically between the two drug combinations, despite observing the same percent change in P and R effect-site concentration. With P high/R low and tamponade, BIS fell from 65+/-5 to 29+/-10 (p<0.05); dobutamine produced opposite effects. With P low/R high, in contrast, BIS was not influenced by either of the hemodynamic challenges.
assistant
Conversely to a high propofol/low remifentanil combination, a low propofol/high remifentanil combination allows constant anaesthetic depth in the face of haemodynamic challenges. Final Decision: yes