摘要:

Acute isovolemic anemia in dogs reduced orterial oxygen content (Cao2) without changing Pao- and AP. Halothane requirement (MAC) remained normal despite reducton of hematocrit to 10 per cent (Cao24.3 vol per cent). Tissue oxygenation was not compromised, as evidenced by the absence of metabolic acidosis, maintenance of mixed venous Po2at 48 mm Hg or greater, and constancy of oxygen consumption. The absence of central nervous system acidosis was suggested by the constancy of Paco2. Cardiovascular changes at 10 per cent hematocrit included increased heart rate and decreased total peripheral resistance. Stroke volume remained constant Therefore, cardiac output increased only as a function of heart rate. The stability of MAC and cardiovascular function levels during anemia is compared with the results in previous hypoxia experiments at similar oxygen content in which significant changes in MAC and tissue oxygenation developed.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Experiments involving lethal and nonlethal drowning were performed in rats and dogs to investigate the effects of aspirated and swallowed water on blood composition, scrum potassium increase owing to hemolysis, damage to pulmonary tissue, and whether blood composition continues to change after cardiac arrest The ratios between aspirated and swallowed water amounted to 1:1 in fresh-water and 1:3 In sea-water drowning. The immediate effects on blood composition were mainly caused by aspirated water, whereas later effects probably were considerably influenced by swallowed water. A maximum of 33 per cent of the potassium increase in lethal drowning was due to hemolysis. Sea water produced more damage to pulmonary tissue than fresh water. After cardiac arrest, blood composition did not continue to change for at least three minutes.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

摘要:

Acute brain injury produces not only abolition of neuronal function but also tissue acidosis, edema, and a state of vasomotor paralysis. This altered vasomotion first affects autoregulation to blood pressure changes and later all cerebral vasomotor control, resulting in paradoxical flow changes with alteration of PCO2. In the initial state, these changes are reversible, and often there is absolute hyperemia. More profound, irreversible brain damage is characterized by very low perfusion. Nevertheless, provided no mechanical obstruction to blood flow exists, as from edema, blood flow in both situations is in excess of metabolic need. This stereotyped derangement is seen with brain tumors, acute cerebro-vascular accidents, hypoxia, and severe trauma to the head, and following neurosurgical intervention. The clinical management of all these conditions must, therefore, follow a similar pattern, which consists of the maintenance of normal levels of perfusion pressure, the avoidance of cerebrovasodilatation from hypercapnia and general anesthetics, and the induction of respiratory alkalosis to offset cerebral acidosis.

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1970

数据来源: OVID