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A porcine model for sequential assessments of cerebral haemodynamics and metabolism
Author(s) -
Åkeson J.,
Nilsson F.,
Ryding E.,
Messeter K.
Publication year - 1992
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1992.tb03491.x
Subject(s) - medicine , hemodynamics , cerebrovascular circulation , anesthesia , cerebral blood flow
We present a physiologically stable porcine model designed for sequential assessments of pharmacological effects on mean hemispheric cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRo 2 ) at sustained normocapnia. The dynamic influence of continuously administered fentanyl (0.040 mg ˙ kg ‐1 ˙ h ‐1 i.v.), nitrous oxide (70%) and pancuronium (0.30 mg ˙ kg ‐1 ˙ h ‐1 i.v.) on these variables was studied in eight normoventilated pigs. CBF was reliably assessable at 10‐min intervals by clearance of intra‐arterially injected 133 Xe, monitored by an extracranial scintillation detector. CMRo 2 was calculated from CBF and the simultaneously measured cerebral arteriovenous difference in blood oxygen content. The intracerebral distribution of a contrast medium injected into the external and internal carotid arteries was studied by angiography, and the cerebral venous outflow was investigated by measurements of the distribution of an intra‐arterially administered non‐diffusible tracer, [ 99m Tc]pertechnetate, to the internal and external jugular veins. After a 3‐h equilibration period, CBF and CMRo 2 were determined on six occasions over a study period lasting 1 h 40 min. The mean ranges of these variables were 56–60 and 1.9–2.0 ml ˙ 100 g ‐1 ˙ min ‐1 , respectively. We conclude that the model enables repeated assessments of CBF and CMRo 2 under stable physiological background conditions and thus valid cerebral pharmacodynamic investigations of drugs given for anaesthesia.