A Renal Factor in Vascular Response to Hemorrhagic and Traumatic Shock

Abstract

A study was made of the response of rats to graded hemorrhage and to trauma in the Noble-Collip drum, comparing control rats with rats nephrectomized immediately before the expt. An apparatus was devised for standardized graded bleeding and infusion. The blood pressure was lowered in successive steps to permit maximum contribution of renal vasotropic factors. In control animals the hemorrhage procedure produced a mortality of 14%. In contrast, nephrectomized rats showed a 70% mortality when subjected to identical procedures. The compensatory nature of the renal contribution to vascular readjustment is also shown by the greater tolerance to blood loss which controls have as compared to nephrectomized animals. The expts. were designed so as to maintain the blood pressure at fixed levels of hypotension for given periods of time. The normal controls achieved this degree of hypotension with less uptake of blood from the reservoir than did the nephrectomized rats. Comparable studies were done with control and nephrectomized animals using drum trauma to induce shock. Only 29% controls died following exposure to 700 revolutions in the drum, whereas 71% of the nephrectomized animals died.