Pulmonary vascular resistance changes in experimental hemorrhagic shock

Hemorrhagic shock was experimentally induced in 40 mongrel dogs, and the resulting pulmonary vascular resistances studied. A mechanical test with closure of the left branch of the pulmonary artery and two pharmacological tests with isoproterenol (isuprel) and cyclic adenosine-monophosphate (cAMP) were performed. The results suggest that there is a block in the beta-control during prolonged shock, and that beta-control is restored by cAMP.