EXPERIMENTAL STUDY AND CLINICAL OBSERVATION OF ARTERIAL OXYGENATION SN CRANIOCEREBRAL INJURIES
- VernacularTitle:颅脑损伤后动脉血氧合程度变化的实验研究与临床观察
- Author:
Yicheng LU
- Publication Type:Journal Article
- From:
Academic Journal of Second Military Medical University
1983;0(S1):-
- CountryChina
- Language:Chinese
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Abstract:
Hypoxemia is the most frequent respiratory abnormality in craniocerebral injuries. we present here the results of a retrospective study of the post-operative changes in arterial oxygenation in 65 cases of craniocerebral injuries. Thirty cases of non-neuro-surgical operations were used as controls.It was found that the PaO2 values in the craniocerebral injury group were significantly lower than those in the controls and often accompanied by obvious hypocapnia and respiratory alkalosis. Seventy-two per cent of the 65 cases had PaO2 values below 80mmHg and 20% below 60mmHg. Obvious hy-poxemia occurred most often in patients with brain stem injuries, extensive cerebral contusions and subdural hematomas. The PaO2 values usually decreased to the lowest level during the period of 24 to 48 hours after operation. There was no mortality in patients whose PaO2 values were above 80mmHg. In contrast, 61% of patients with PaO2 below 60mmHg showed poor prognosis.ICP mornitoring performed in 5 cases of craniocerbral injuries suggested that increased ICP was, in some way, associated with lower PaO2 .Nine dogs, anesthetized with sodium pentobarbital and under controlled ventilation, were studied for changes of arterial blood gases after ICP had been increased by epidu-ral balloon inflation to 50 and 100 mmHg for 30 minutes. All the animals consistently showed a decrease of PaO2 accompanied by a slight increase of PaCO and decrease of pH values after elevaion of ICP.The extent of these changes was greater when ICP was 100mmHg than when it was 50mmHg.Hyperventilation at ICP of 100mmHg could not restore PaO2 to baseline in most animals although their PaCO2 was decreased below baseline. These results indicate that acutely increased ICP has a direct effect on lungs, which is responsible for venous admixture and hypoxemia.The mechanisms,by which hypoxemia is caused after craniocerebral injuries, are discussed, ventilation-perfusion imbalance is considered to be a main factor for hypoxemia.we conclude that instant examination of arterial oxygenation is helpful to the recognition of the status of the patient's respiratory function, to the guidance of medical care and to the assessment of patient's prognois.It is suggested that effective control of increased ICP in head injuries can prevnt further deterioration of the respiratory function.
