Ausina A, Báguena M, Nadal M, Manrique S, Ferrer A, Sahuquillo J, Garnacho A
Department of Intensive Care Unit, Vall d'Hebron University Hospitals, Barcelona, Spain.
Acta Neurochir Suppl. 1998;71:1-4. doi: 10.1007/978-3-7091-6475-4_1.
Hyperventilation (HV) is routinely used in the management of increased intracranial pressure (ICP) in severe head injury. However, this treatment continues to be controversial because it has been reported that long-lasting reduced cerebral blood flow (CBF) due to profound sustained hypocapnia may contribute to the development or deterioration of ischemic lesions. Our goal in this study was to analyze the effects of sustained hyperventilation on cerebral hemodynamics (CBF, ICP) and metabolism (arterio jugular differences of lactates = AVDL). CO2-reactivity and CBF was estimated using AVDO2 (arteriojugular differences of oxygen content). Global cerebral ischemia and increased anaerobic metabolism were considered according to AVDO2 and AVDL respectively. Thirty-three patients with severe and moderate head injury and increased ICP were included. Within 72 hours after accident, patients were hyperventilated for a period of 4 hours. During this time jugular oxygen saturation (SjO2), arterial oxygen saturation (SaO2), ICP, mean arterial blood pressure (MABP), AVDO2 and AVDL were recorded. In our study, most patients preserved CO2-reactivity (88.2%). In these cases HV was very effective in lowering ICP. Our findings showed that this reduction was due to a CBF decrease. According to basal AVDO2 twenty-five patients (75.7%) were considered as hyperemic and eight (24.2%) as not hyperemic. Global ischemia and increased anaerobic metabolism were detected in one case in the non-hyperemic group. According to AVDO2 and AVDL, no adverse effects were found during four hours of HV in hyperemic patients. Nevertheless, AVDO2 and AVDL are global measurements and might not detect regional ischemia surrounding focal lesions such as contusions and haematomas. We suggest that monitoring of AVDO2 or other haemometabolic variables should be mandatory when sustained HV is used in the management of head injury patients.
过度通气（HV）常用于重型颅脑损伤患者颅内压（ICP）升高的治疗。然而，这种治疗方法仍存在争议，因为有报道称，由于严重持续性低碳酸血症导致的脑血流量（CBF）长期减少可能会促使缺血性病变的发生或恶化。本研究的目的是分析持续性过度通气对脑血流动力学（CBF、ICP）和代谢（动静脉乳酸差异=AVDL）的影响。使用动静脉氧含量差异（AVDO2）评估二氧化碳反应性和CBF。分别根据AVDO2和AVDL判断是否存在全脑缺血和无氧代谢增加。纳入33例中重型颅脑损伤且ICP升高的患者。事故发生后72小时内，对患者进行4小时的过度通气。在此期间记录颈静脉血氧饱和度（SjO2）、动脉血氧饱和度（SaO2）、ICP、平均动脉压（MABP）、AVDO2和AVDL。在我们的研究中，大多数患者保留了二氧化碳反应性（88.2%）。在这些病例中，HV对降低ICP非常有效。我们的研究结果表明，这种降低是由于CBF减少所致。根据基础AVDO2，25例患者（75.7%）被认为是充血性的，8例（24.2%）不是充血性的。在非充血性组的1例患者中检测到全脑缺血和无氧代谢增加。根据AVDO2和AVDL，充血性患者在4小时的HV期间未发现不良反应。然而，AVDO2和AVDL是整体测量指标，可能无法检测到挫伤和血肿等局灶性病变周围的局部缺血。我们建议，在对颅脑损伤患者进行持续性HV治疗时，应强制监测AVDO2或其他血液代谢变量。
