title: Hypertonic saline is a negative inotropic agent in normovolumic dogs.
abstract: The inotropic effects of hypertonic saline (HS) and hyperosmotic dextrose (HD; 2,400 mosmol/l, 4 ml/kg) were determined in normovolumic, chloralose-anesthetized, intact (n = 14) and autonomically blocked (n = 8) dogs. Solutions were infused intravenously over 3 min. HS and HD rapidly increased preload in both intact and autonomically blocked dogs, as assessed by significant (P < 0.05) increases in plasma volume, end-diastolic volume, and end-diastolic pressure. In intact dogs, HS produced a nonsignificant decrease in end-systolic elastance (Ees) and a nonsignificant increase in the maximal rate of change of left ventricular pressure (dP/dtmax) and cardiac output, whereas HD produced a significant increase in Ees, dP/dtmax, and cardiac output. In autonomically blocked dogs, HS significantly decreased Ees and significantly increased dP/dtmax but did not alter cardiac output, whereas HD significantly increased Ees, dP/dtmax, and cardiac output. We conclude that in normovolumic animals, HS is a negative inotropic agent, HD is a positive inotropic agent, and the in vivo effect of an ionic hyperosmotic agent (HS) differs from that of a nonionic hyperosmotic agent (HD).
authors.affiliation: College of Veterinary Medicine, Ohio State University, Columbus 43210.
authors.forename: P D
authors.initials: PD
authors.lastname: Constable
authors.forename: W W
authors.initials: WW
authors.lastname: Muir
authors.forename: P F
authors.initials: PF
authors.lastname: Binkley
mesh_terms: D000818:Animals; D001340:Autonomic Nerve Block; D001810:Blood Volume; D004285:Dogs; D004548:Elasticity; D005947:Glucose / Q000494:pharmacology; D008297:Male; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000187:drug effects*; D012016:Reference Values; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012996:Solutions; D013599:Systole
chemical_list: D012462:Saline Solution, Hypertonic; D012996:Solutions; D005947:Glucose