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Biomedical subjects

K T Foley

Publications and source records attributed to K T Foley.

5 recordsLinked to original sources
PubMed1991

Pulmonary embolism from a venous thrombosis distal to the popliteal vein.

A case of pulmonary embolism from a venous thrombosis distal to the popliteal vein is reported. This occurred despite venographic and ultrasound verification that the thrombus had not extended to the popliteal vein. The medical literature supports expectant treatment of "calf-only" venous thrombi. Our case clearly demonstrates that clinically significant pulmonary emboli can arise from calf vein thrombi without popliteal involvement.

Adult↗
PubMed1990

Receptor interactions in modulating ventilatory activity.

The ventilatory control system utilizes a variety of sensory receptor groups, including chemoreceptors and mechanoreceptors, to provide feedback concerning the status of controlled variables. Most ventilatory responses to altered receptor inputs generally involve a complex interaction between several receptor groups, central integrative mechanisms, and other modulatory inputs (e.g., "state," hormonal, or neurotransmitter status). Because the control system is complex, nonlinear, and dynamic, the ultimate ventilatory response elicited by a given stimulus is not easy to predict based on the reflex effects of individual receptor groups studied in isolation. A full understanding of the role that sensory receptors play in ventilatory control requires information concerning interactions among receptor groups and with other elements of the control system. The complexity of the problem and the lack of a uniform definition of the term "interaction" has hindered research in this area. An interaction is defined as a nonadditive relationship between independent inputs to the system. Within this definition, five domains of interaction are described. 1) Algebraic interactions occur in ventilation and/or its components because of their multiplicative and nonlinear relationship. 2) Closed-loop interactions occur because of the prevalence of feedback loops within the respiratory control system. 3) Neural interactions reflect central nervous system integration of simultaneous receptor inputs and are demonstrated when feedback loops are opened. Three subdomains of neural interactions are defined: modulatory, dynamic, and range-specific neural interactions. 4) Mechanical interactions result from nonlinear transformations of motoneuron output into mechanical actions. 5) Adaptive interactions occur when paired receptor or modulatory inputs alter future responses. To understand the role of any sensory receptor group in ventilatory control, it is necessary to define its interactions with other control system elements in each of these domains. Understanding the mechanisms of these interactions requires detailed information about the physical system subserving ventilatory control (mechanics and gas exchange) and the relevant properties of the neural network coordinating their actions.

Adaptation, Physiological↗
PubMed1989

Progression of hydrocephalus during corticosteroid therapy for neurosarcoidosis.

We describe a patient with sarcoid meningitis and hydrocephalus who improved rapidly after initiation of oral prednisone therapy, but who later decompensated acutely and required an emergency ventriculoperitoneal shunt. Hydrocephalus associated with neurosarcoidosis may progress despite steroid treatment, even when symptoms have improved. If hydrocephalus associated with neurosarcoidosis is treated with corticosteroids and without a shunt procedure we suggest that the corticosteroids should be continued at high doses for a prolonged period.

Adult↗
PubMed1989

A comparison of the effects of suxamethonium, atracurium and vecuronium on intracranial haemodynamics in swine.

Sixteen Yorkshire swine weighing 15-20 kg were studied to compare the effects of suxamethonium, atracurium and vecuronium on intracranial pressure (ICP), heart rate (HR), arterial blood pressure (BP), and cerebral perfusion pressure (CPP) in swine with normal or elevated ICP. In each animal an intracranial pressure-volume curve was produced by the inflation of an epidural balloon. The baseline ICP (Po), the ICP at the inflection point (Pi) and on the steep portion (Pmax) of the pressure-volume curve were identified and the balloon volumes recorded. The animals were assigned to receive either suxamethonium 1.0 mg/kg, atracurium 0.6 mg/kg, vecuronium 0.2 mg/kg, or saline placebo intravenously at three conditions: First, with the epidural balloon deflated Po, next at Pi, then at Pmax. Neither atracurium, vecuronium, nor placebo produced any statistically significant effect on HR, BP, ICP, or CPP at any baseline level of ICP. Suxamethonium produced an early fall in ICP (0.8 +/- 0.3, 2.6 +/- 1.0 and 3.5 +/- 1.3 mmHg at Po, Pi and Pmax respectively: P = .0005) followed by a rapid rise above the pre-infusion level (1.8 +/- 0.6, 2.8 +/- 0.6 mmHg, and 2.2 +/- 0.5 mmHg at Po, Pi and Pmax respectively: P = .0005). A fall in BP coupled with the rise in ICP resulted in a fall in CPP (5.8 +/- 2.3, 6.1 +/- 1.2, and 6.3 +/- 1.8 mmHg at Po, Pi and Pmax respectively: P = .0005). Although the fall in CPP was not large, in the presence of elevated ICP, where CPP already is marginal, such a decrease may compromise cerebral blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗