COMPARATIVE STUDIES OF PULSATILE AND NON-PULSATILE FLOW DURING CARDIOPULMONARY BYPASS .3. RESPONSE OF ANTERIOR-PITUITARY GLAND TO THYROTROPIN-RELEASING-HORMONE

Abstract

During nonpulsatile cardiopulmonary bypass, the anterior pituitary gland apparently fails to respond to the stimulus of thyrotropin-releasing hormone (TRH). This is in contrast to the normal response seen during closed cardiac and general surgical procedures. The Stockert pulsatile pump system described was employed in a comparative study of TRH responses in 20 patients subjected to pulsatile or nonpulsatile perfusion during open-heart surgery. In the nonpulsatile group, a consistently subnormal response to TRH injection was again found. In the pulsatile group, however, the pituitary response to TRH was normal in 9 patients out of 10. The quantitiative difference between the groups was statistically highly significant (P < 0.005). The subnormal pituitary function seen with nonpulsatile bypass may be prevented by the use of pulsatile perfusion.