title: Early experiences of vasodilators and hypotensive anesthesia in children.
abstract: The physiological application of OHMS LAW explains the basis of hypotensive anesthesia. V = IR translates into: Pressure = Flow × Resistance or Blood pressure = Cardiac Output × Peripheral Resistance. If peripheral resistance is reduced by a vasodilator such as sodium nitroprusside (a short acting, vascular smooth muscle relaxant) or phenoxybenzamine (a long acting α adrenoreceptor antagonist), blood pressure will fall and vasoconstriction and bleeding will be reduced. A less desirable alternative to lowering blood pressure could be to reduce cardiac output by suppressing myocardial contractility using a ß(1)  adrenoceptor antagonist or an inhalational agent such as isoflurane.
authors.affiliation: (Formerly) Royal Childrens Hospital, Melbourne, Victoria, Australia. tckbrown@netspace.net.au
authors.forename: T C K
authors.initials: TC
authors.lastname: Brown
mesh_terms: D000758:Anesthesia / Q000379:methods*; D016063:Blood Loss, Surgical; D001794:Blood Pressure / Q000502:physiology*; D002648:Child; D005730:Ganglionic Blockers / Q000627:therapeutic use*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007036:Hypothermia, Induced; D033221:Jehovah's Witnesses; D008099:Liver / Q000601:surgery; D009125:Muscle Relaxants, Central / Q000627:therapeutic use; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009599:Nitroprusside / Q000627:therapeutic use; D012600:Scoliosis / Q000601:surgery; D014665:Vasodilator Agents / Q000627:therapeutic use
chemical_list: D005730:Ganglionic Blockers; D009125:Muscle Relaxants, Central; D014665:Vasodilator Agents; D009599:Nitroprusside