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F D Brown

Publications and source records attributed to F D Brown.

44 records · Page 3Linked to original sources
PubMed1977

Physiological consequences of experimental cerebral missile injury and use of data analysis to predict survival.

The authors describe cerebrovascular and cerebral metabolic changes in monkeys, subjected to cerebral missile injury. After injury with BB pellet at 90 m/sec, there is a rapid rise in intracranial pressure (ICP), which reaches a peak 2 to 5 minutes posttrauma, and then falls to about 20 to 30 mm Hg. This, with a fall in mean blood pressure (MBP), results in a 50% reduction in cerebral perfusion pressure (CPP), Cerebral blood flow (CBF) is also reduced, although acutely there is no close relationship with (CPP). Cerebrovascular resistance falls initially and then at 30 minutes rises to very high values. Cerebral metabolic rates (CMR's) for oxygen fall after injury and remain low for the rest of the animal's life; CMR's for lactate rise immediately after injury and persists for 5 hours, then fall. After injury with a faster missile (180 m/sec), the ICP rises higher and faster, and the peak is shorter. The CCP is reduced in this injury to approximately 30 mm Hg, and only one animal survived more than 1 hour. With the conventional forms of data analysis, the length of survival after injury correlates well with MBP, ICP, and CBF, but separately they were completely unsatisfactory for prediction of an individuals prognosis. With the technique of multiple linear regression analysis, the survival of individual animals could be predicted with great accuracy. This is possible also when two postinjury parameters,CBF and MBP, are used.

Animals↗
PubMed1977

Somatosensory evoked potentials, cerebral blood flow and metabolism following cerebral missile trauma in monkeys.

Somato sensory evoked potentials (SEP), cerebral blood flow and cerebral metabolism were studied in seven rhesus monkeys before and after a right occipito-frontal missile injury with an air rifle. The sensory evoked potential was present shortly after injury though markedly altered in shape. There was a very close correlation (r2 equal to 0.83) between SEP and cerebral blood flow on the uninjured side five minutes after injury. On the injured side, this was also noted but the amplitude of the SEP was much smaller, perhaps due to direct injury. If the flow in either hemisphere fell below 15-20 mls/100 gm/min, the evoked response disappeared, but in several animals a subsequent increase in flow was associated with a return of electrical activity. There was no correlation with cerebral perfusion pressure or cerebral metabolic rates for oxygen or lactate production, though it is likely that this is not due to physiological reasons but rather methodological. It might be inferred from these results that adequate flow is vital for the preservation and return of electrical activity following brain injury.

Animals↗
PubMed1977

Effect of sodium nitroprusside on cerebral blood flow in conscious human beings.

Hemispheric cerebral blood flow was measured in 14 patients prior to and after the injection of sodium nitroprusside. The intracarotid method of Xenon was utilized, and flow was calculated by the flow initial technique. With a small reduction in blood pressure during the administration of sodium nitroprusside, the cerebral blood flow fell significantly by 15.9+/- 5.6%.

Adult↗
PubMed1976

Effects of trimethaphan and sodium nitroprusside on cerebral blood flow in rhesus monkeys.

In tranquilised spontaneously breathing rhesus monkeys we have found that trimethaphan can reduce systemic blood pressure by 20% with little or no change in CBF. This was in marked contrast to those given nitroprusside which showed signs of loss of autoregulation at a 5% MBP reduction. It is our opinion that the divergence of these results from other work might be explained in part by differing anaesthetic techniques and species variations. On this experience we would be hesitant to use sodium nitroprusside or a hypotensive agent in any patient where cerebral blood flow might be already compromised.

Animals↗
PubMedDate not supplied

The effects of sodium nitroprusside and trimethaphan camsylate on cerebral blood flow in rhesus monkeys.

Hemispheric cerebral blood flow was measured in the rhesus monkey before and after infusion of the hypotensive agents sodium nitroprusside and trimethaphan camsylate. The intracarotid injections of 133Xe was utilized, and flow was calculated by the "flow initial" technique. Cerebral blood flow did not change significantly with the administration of trimethaphan camsylate. However, with a small reduction in blood pressure (10.6%) during the administration of sodium nitroprusside, the cerebral blood flow fell significantly (15.4%).

Animals↗