Читать книгу Manual of Equine Anesthesia and Analgesia - Группа авторов - Страница 331

 Intracranial pressure (ICP) is maintained at approximately 2 mmHg in conscious healthy horses, even when the head is lowered below heart level.

 Normal neonatal foals in the first 24 hours after birth have ICP between 2 and 15 mmHg and a CPP of in the range 50–109 mmHg.

 Mean (SD) values for ICP in adult standing horses are 2 (4) mmHg and for CPP are 102 (26) mm Hg.

 Cerebral perfusion pressure is the difference between systemic mean arterial blood pressure and ICP, and should be at least 60 mmHg.

 When CPP is below this value or cardiac output decreases to less than half‐normal values, cerebral circulation becomes insufficient.

 In isoflurane‐anesthetized horses maintained at 1.2 MAC, ICP increases and is higher in dorsal than in lateral and sternal recumbency (34 vs 24 vs 19 mmHg, respectively). Head down position for dorsal and sternal recumbency increases ICP further. Because MAP is higher (105 mmHg) in sternal recumbency, CPP is higher (71 mmHg for sternal with head up and 87 mmHg for sternal with head down); intermediate for dorsal recumbency (MAP of 85 mmHg for head level with the thorax and CPP of 51 mmHg; MAP of 76 mmHg for head down and CPP of 55 mmHg); and lower for lateral recumbency (MAP of 72 mmHg and CPP of 48 mmHg).

 Increasing end‐tidal concentrations of the inhalational anesthetic causes significant dose‐dependent decreases in MAP and CPP, but no change in ICP.

 Mechanical ventilation causes a significant decrease in MAP and ICP but no change in CPP.