ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

Elevated intrathoracic pressure due to positive end-expiratory pressure (PEEP) has the potential for increasing intracranial pressure (ICP) and reducing arterial blood pressure (HP). 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 1CP. PEEP application in the absence of oleic acid embolization of the lungs caused electroencephalographic abnormalities in 77 per cent of these cats, while pupillary diameters increased in 56 per cent. Animals embolized with oleic acid had significantly less (P< .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 per cent of cats given oleic acid when PEEP was applied.In 82 per cent of the PEEP applications (n = 44) in both experimental groups only insignificant increases in intracranial tension occurred (average peak ICP gain < 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 cuts given oleic acid.The results indicate a potential for PEEP to evoke neurologic 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.

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

The effect of halo thane on net myocardial oxygen balance of ischemic myocardium was studied m the non-failing canine heart. Myocardial ischemia was produced by repeated reversible occlusions of a coronary artery; the severity of ischemia was estimated by summating ST-segment elevations (ΣST) obtained by epicardial ECG mapping at 15 to 18 sites. Control measurements were obtained before and after administration of halothane (0.75 percent) to six dogs with chloralose—urethane basal anesthesia. Halothane was associated with significant decreases of systemic arterial pressure (P< .001), heart rate (P< .01), and the product of systolic arterial pressure × heart rate (P< .01), an indirect index of myocardial oxygen consumption, while left atrial pressure remained unchanged at normal levels. ΣST during occlusion was less (P< .001) during halothane (26.5 ± 7.4 {SD} mv) than before (36.G ± 5.4 mv) or after (34.4 ± 8.2 mv) its administration. Thus, halo thane decreased the severity of experimentally-induced myocardial ischemia in the non-failing canine heart. The data suggest that, in the absence of ventricular failure, halothane influences the relationship between myocardial oxygen supply and demand in a favorable direction when coronary blood flow is limited.

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

Denervation injuries in baboons were used to define the time course of the hyperkalemic response to succinylcholine. Half-peak increase in serum potassium (2.7S mEq/1) occurred 8.4 days following injury. Peak increase (5.5 mEq/1) appeared 14 days after injury. However, changes in potassium levels begin as early as four days after injury. Succinylcholine or other depolarizing muscle relaxants should not be used after the fourth day following an Injury or denervation that involves two or more limbs.

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

The radioactive-microsphere technique was used to determine distribution of cardiac output and regional blood flow in rhesus monkeys before and 10, 20, 40, and SO minutes after induction of epidural anesthesia with lidocaine (1 per cent) without epinephrine. Four monkeys were studied during low epidural anesthesia (sensory level T10) and five other monkeys were studied during high epidural anesthesia (sensory level T1). During T10 epidural anesthesia, blood flow (per 100 g tissue) to die lower extremity was significantly increased 10 minutes after induction of anesthesia. There was no other significant change in regional blood flow during T10 epidural anesthesia. During T1 epidural anesthesia, blood flow to the heart was significantly reduced at 10 minutes, blood flow to the liver was significantly reduced at 10 and 40 minutes, blood flows to kidneys and miscellaneous organs (lymph nodes, salivary glands, etc.) were significantly reduced at 10, 20, and 40 minutes, and blood flow to the brain was significantly reduced throughout anesthesia. Vascular resistance in the lower extremity was reduced in each monkey following epidural anesthesia, indicating arteriolar dilatation. Also, during both levels of anesthesia, the lungs received an increased proportion of the microspheres, suggesting an increased peripheral arteriovenous shunting of micro-spheres due to the arteriolar dilatation.

ISSN:0003-3022    

出版商:OVID    

年代:1976

数据来源: OVID