Aidinis S J, Lafferty J, Shapiro H M
Anesthesiology. 1976 Sep;45(3):275-86. doi: 10.1097/00000542-197609000-00004.
Elevated intrathoracic pressure due to positive end-expiratory pressure (PEEP) has the potential for increasing intracranial pressure (ICP) and reducing arterial blood pressure (BP). Such changes could critically reduce cerebral perfusion pressure (CPP = BP - ICP), This possibility was investigated in 15 cats with artificially-produced expanding intracranial masses (intracranial balloon). The interrelationships among ICP and central venous and arterial pressures were observed during application and removal of graded levels of PEEP (5, 10, 15 cm H2O). The electroencephalogram and pupillary diameters were monitored. At various levels of ICP, nine of the cats were given oleic acid intravenously to embolize the lung and cause pulmonary dysfunction. In cats not given oleic acid, PEEP caused a maximal reduction in cerebral perfusion pressure of 45 +/- 4 torr(SEM), accompanied by variable changes in ICP. PEEP application in the absence of oleic acid embolization of the lungs caused electroencephalographic abnormalities in 77% of these cats, while pupillary diameters increased in 56%. Animals embolized wwith oleic acid had significantly less (P less than .001) severe CPP reductions (mean 21 +/- 4 torr) than did the non-embolized animals, and developed no EEG change due to PEEP. However, increases in pupillary diameter still occurred in 33% of cats given oleic acid when PEEP was applied. In 82% of the PEEP applications (n = 44) in both experimental groups only insignificant increases in intracranial tension occurred (average peak ICP gain less than 1.5 torr). Abrupt increases in ICP exceeding 11 torr (15 cm H2O) occurred in four animals in each group. This happened most frequently (63 per cent) when the intracranial tension before PEEP was above 15 torr. Sudden removal of or reduction in PEEP was accompanied by increases in arterial and intracranial pressures in both groups, although this response was attenuated in the cats given oleic acid. The results indicate a potential for PEEP to evoke neurolgic complications in patients who have intracranial disease and that the presence of pulmonary disease may attenuate these deleterious side effects. Monitoring of neurologic function as well as blood-gas and cardiovascular effects of PEEP in patients who have intracranial disease is suggested.
呼气末正压（PEEP）导致的胸腔内压力升高有可能增加颅内压（ICP）并降低动脉血压（BP）。这种变化可能会严重降低脑灌注压（CPP = BP - ICP）。在15只人工制造颅内占位性病变（颅内球囊）的猫身上对这种可能性进行了研究。在应用和撤除不同水平的PEEP（5、10、15厘米水柱）期间，观察ICP与中心静脉压和动脉压之间的相互关系。监测脑电图和瞳孔直径。在不同ICP水平下，给9只猫静脉注射油酸以栓塞肺部并导致肺功能障碍。在未给予油酸的猫中，PEEP导致脑灌注压最大降低45±4托（标准误），同时ICP有不同变化。在没有油酸栓塞肺部的情况下应用PEEP，77%的这些猫出现脑电图异常，56%的猫瞳孔直径增大。与未栓塞的动物相比，用油酸栓塞的动物CPP严重降低的情况明显较少（P<0.001）（平均21±4托），并且未因PEEP出现脑电图变化。然而，在应用PEEP时，33%给予油酸的猫瞳孔直径仍会增大。在两个实验组中，82%的PEEP应用（n = 44）仅出现颅内压无明显升高（平均ICP峰值升高小于1.5托）。每组有4只动物出现ICP突然升高超过11托（15厘米水柱）。这种情况最常发生在（63%）PEEP应用前颅内压高于15托时。两组在突然撤除或降低PEEP时，动脉压和颅内压均升高，尽管在给予油酸的猫中这种反应有所减弱。结果表明，PEEP有可能在患有颅内疾病的患者中引发神经并发症，而肺部疾病的存在可能会减轻这些有害副作用。建议对患有颅内疾病的患者监测神经功能以及PEEP对血气和心血管的影响。
