Experimental investigations on canine endotoxic shock: changes in hemodynamics and involvement of some humoral factors
Guo, H.Y.; Sun, R.Y.
Chinese Medical Journal 95(8): 613-621
1982
ISSN/ISBN: 0366-6999 PMID: 6291873 Document Number: 184395
Hemodynamic and selected humoral responses to endotoxemia were assessed in dogs anesthetized with pentobarbital. Measurements included systemic and pulmonary arterial pressures (SAP, PAP), right and left atrial pressures (RAP, LAP), heart rate (HR) and stroke volume (SV). Blood samples were collected for plasma noradrenaline (NA), acetylcholinesterase (AchE) activity, cAMP and cGMP. Cardiac output (CO), total systemic peripheral resistance (TSPR) and total pulmonary vascular resistance (TPVR) were calculated from standard equations. After a short control period, 5 or 7 mg/kg wt Escherichia coli endotoxin was given as an i.v. bolus. Although the survival time of shocked animals varied, the SAP response pattern was essentially the same in all shocked dogs; the CO and TSPR response patterns were quite different in different animals, which may be ascribed mainly to individual responsiveness. The hemodynamic response patterns could be divided into 3 categories, i.e., high output-low resistance (HoLr), low output-high resistance (LoHr) and low output-low resistance (LoLr). The majority of shocked animals began and terminated with LoLr. HoLr seemed the most effective compensation, LoHr was less effective, and LoLr was least effective. The alterations in humoral factors suggest that different hemodynamic patterns may be attributed to the adrenergic and cholinergic activity changes and increased cholinergic activity plays a part in the pathogenesis of shock, particularly in LoLr response.