Laptook A, Stonestreet B S, Oh W
Early Hum Dev. 1982 Jan;6(1):99-107. doi: 10.1016/0378-3782(82)90063-9.
The potential use of a piglet as a model for investigation of brain blood flow was evaluated by assessing the presence of autoregulation in 11 spontaneously breathing newborn piglets. Blood pressure was altered by phlebotomy. When the mean arterial blood pressure was greater than 50 mm Hg, no significant change in brain blood flow (microsphere technique) occurred (r = 0.04), indicating the presence of autoregulation. When the animals became hypotensive a pressure passive relationship exists between brain blood flow and mean arterial blood pressure. However, since the piglets breathed spontaneously and hyperventilated during hypotension, both the mean arterial blood pressure and PaCO2 fell and both correlated with brain blood flow. Thus, it cannot be determined which factor is responsible for the reduction in flow. The blood flow to the specific regions of the brain (cerebrum, cerebellum, brainstem) and mean arterial blood pressure also showed no correlation when the latter was greater than 50 mm Hg. During hypotension, each region demonstrates pressure passive relationships, but the reduction in blood flow is most pronounced in the cerebrum, less in the cerebellum, and least in the brainstem (mean +/- S.E., 64 +/- 8%, 41 +/- 13%, 32 +/- 13% reductions from control respectively, P less than 0.05). The study indicates that a newborn piglet may serve as an appropriate model for the study of brain hemodynamics particularly with regard to autoregulation. Furthermore, during hypotension, preferential protection of vital regions of the brain (cerebellum and brainstem) occur which may have important implications in interpreting the effect of hypotension on the newborn central nervous system.
通过评估11只自主呼吸的新生仔猪的自动调节功能，对仔猪作为脑血流研究模型的潜在用途进行了评估。通过放血改变血压。当平均动脉血压大于50 mmHg时，脑血流（微球技术）无显著变化（r = 0.04），表明存在自动调节。当动物出现低血压时，脑血流与平均动脉血压之间存在压力被动关系。然而，由于仔猪在低血压期间自主呼吸且过度通气，平均动脉血压和动脉血二氧化碳分压均下降，且两者均与脑血流相关。因此，无法确定是哪个因素导致了血流减少。当平均动脉血压大于50 mmHg时，脑的特定区域（大脑、小脑、脑干）的血流与平均动脉血压也无相关性。在低血压期间，每个区域均表现出压力被动关系，但大脑血流减少最为明显，小脑次之，脑干最少（平均±标准误，分别较对照降低64±8%、41±13%、32±13%，P<0.05）。该研究表明，新生仔猪可能是研究脑血流动力学尤其是自动调节功能的合适模型。此外，在低血压期间，脑的重要区域（小脑和脑干）会出现优先保护，这可能对解释低血压对新生儿中枢神经系统的影响具有重要意义。
