Midazolam-fentanyl-isoflurane anaesthesia is suitable for haemodynamic and fluid balance studies in pigs

Abstract

SummaryThe domestic pig is a useful model in certain areas of biomedical research. Effective use of this species is often encumbered by lack of reference values in conscious as well as anaesthetized animals. Anaesthesia itself influences physiological and biological variables; the anaesthetic technique often affects experimental results. The relationship between anaesthesia and haemodynamics is well characterized in man, but less established in pigs.We studied the effect of midazolam-fentanyl-isoflurane anaesthesia in six immature, male, domestic pigs (Norwegian landrace). Haemodynamic variables (heart rate, arterial systolic, mean, diastolic pressures, pulmonary systolic, mean, diastolic pressures, pulmonary capillary wedge pressurel, tissue perfusion, lymph flow (thoracic duct) were recorded for 3 h in animals with open chest through midline sternotomy.Variables relevant to fluid balance, e.g. interstitial hydrostatic pressure (Pil, serum-colloid osmotic pressure (s-COP) and serum-albumin (s-albumin) and -protein Is-protein) concentrations were measured.With the chosen anaesthetic technique haemodynamic variables, including lymph flow, and laboratory variables remained constant during the study period. Most variables were similar to conditions in humans. In contrast to adult humans exposed to the same anaesthetic technique, these pigs had lower haemoglobin-, s-albumin-and s-protein concentrations. A finding which may reflect immaturity. Liver and lung perfusion decreased significantly during the study period whereas perfusion of the other organs studied remained constant. Lack of responses to defined noxious stimuli during the study period suggest adequate analgesia. We conclude that midazolam, fentanyl and isoflurane provide cardiovascular stability including normal microvascular fluid exchange, which are essential elements for securing the quality of results obtained during cardiovascular research in anaesthetized pigs.

Cardiovascular effects of lumbar epidural anaesthesia in isoflurane-anaesthetised pigs during surgical removal of the liver

“…If a larger sample could be used it would have allowed the use of parametric tests, which are more sensitive to differences, should they exist, as the actual observations are evaluated instead of the ranks of the observations. Mean heart rates in this investigation (Table 1) were within range of the reported values for anaesthetised pigs (80-130 beats/min) 13 and for isoflurane-fentanyl anaesthetised pigs (108 beats/min) 4 . However, it should be regarded as of clinical significance that the ropivacaine epidural prevented the steep increase in HR in the AL-group that was observed in the A-group during abdominal surgery (Fig.…”

Intraaortic Counterpulsation During Cardiopulmonary Bypass Impairs Distal Organ Perfusion

“…All animals were fasted overnight with continuous access to water. Anesthesia included midazolam, fentanyl, and pancuronium infusion, and isoflurane inhalation [18].…”

Does insulin impact cold-induced fluid- and protein-extravasation?

“…General anesthesia was maintained by volume-controlled normoventilation with 0.5% isoflurane in 50% oxygen and a continuous i.v. infusion of midazolam (0.5 mg/kg/h) and fentanyl (7.5 lg/kg/h) as previously described [16]. In addition pancuronium (45 lg/kg/h) was added to avoid shivering during the experiments.…”

“…In addition pancuronium (45 lg/kg/h) was added to avoid shivering during the experiments. The protocol allowed for adjustments of the inspired isoflurane concentrations in the order of 0.5-2.0 vol% according to reactions to standardized noxious stimuli [16].…”