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Biomedical subjects

W E Fordyce

Publications and source records attributed to W E Fordyce.

At least 55 records · Page 3Linked to original sources
PubMed1982

A behavioural perspective on chronic pain.

This review outlines a behavioural view of chronic pain, in which pain behaviours are considered as operants. This view is supported by experiments in which pain behaviour is shown to be under the influence of environmental factors. The number of exercises performed by pain patients working to tolerance tend to be in multiples of five, rather than following a chance distribution. The exercise deficit seen in pain patients under conditions where exercises are counted does not occur when feedback is removed, and under these circumstances pain patients do not differ from normals. Other studies show that tolerance can be increased by verbal reinforcement, and that pain ratings are influenced by the presence or absence of a patient's spouse. Implications of these findings for the maintenance or reduction of chronic pain are discussed.

Back Pain↗
PubMed1982

Geriatric patients.

Explore the source record for details and available documents.

Activities of Daily Living↗
PubMed1982

Activity patterns of married and single individuals after stroke.

This was an exploratory study in the social-leisure activity levels of married and single individuals after stroke. A 60-item behavioral frequency scale was administered to 42 married and 31 single subjects. Single persons showed higher levels of participation in performing personal care, home management and social interaction activities. Both groups participated in social activities and recreational events outside the home. It might be hypothesized that married persons participate less often in social interaction activities because they can rely on their spouses for social interaction. Many questions must be resolved before full confidence can be placed in activity pattern descriptions of a stroke population.

Activities of Daily Living↗
PubMed1981

Behavioral methods in medical rehabilitation.

The process of assimilation of physical disability and of patient management strategies in medical rehabilitation are analyzed in behavioral terms. Four major problem areas are identified; (1) the aversive characteristics of forced entry from accidental injury or illness into permanent disability; (2) relinquishing pre-onset behavior no longer appropriate because of the disability; (3) acquisition of disability appropriate behaviors; and (4) maintenance of performance or generalization of treatment effects. Each of those problem areas is analyzed in behavior-consequence terms. Case examples are presented to illustrate both analysis of problems in behavioral terms and contingency management strategies for helping.

Behavior↗
PubMed1981

Dynamics of ventilatory response to exercise in humans.

The dynamics of the ventilatory response to moderate exercise on a bicycle ergometer have been studied in humans. The work load was varied between 25 and 100 W as a pseudorandom binary sequence (PRBS) that enabled the impulse responses to be calculated by cross-correlation techniques. The response of all five subjects exhibited a bimodal response, i.e., a fast component that was followed after a delay by a slow component. The fast component accounted for a relatively small proportion of the total response. Also, it was demonstrated that to identify the rapid component it was necessary to excite the respiratory system with an input containing highfrequency components; this result was used to reconcile the findings from this study with those of previous investigation.

Adult↗
PubMed1980

Ventilatory responses to intravenous and airway CO2 administration in anesthetized dogs.

The ventilatory responses to steady-state venous CO2 loading (iv CO2) and CO2 inhalation have been observed in chloralose-urethan-anesthetized dogs. Intravenous CO2 was administered by increasing the CO2 fraction of gas ventilating a membrane gas exchanger in an arteriovenous bypass; blood flow rate was fixed at 30 ml/min. During the study, we identified a time-dependent hyperventilation in all 14 experimentally treated dogs and in 4 additional sham-treated dogs. When we tested 8 of these animals with a protocol having small progressive increments in iv CO2 loading rate, we observed a response approaching isocapnia during iv CO2 and a large hypocapnia when we returned to control conditions. The use of a randomized protocol in 6 animals demonstrated the necessity of accounting for this systematic base-line shift, because before doing so the response depended more on the passage of time than on the nature of the CO2 load. After this analytical adjustment was made, there was no significant difference between the respiratory controller gains (delta nu E/delta Paco2) for inhaled and iv CO2.

Anesthesia↗
PubMed1979

Arterial PCO2 response to intravenous CO2 in awake dogs unencumbered by external breathing apparatus.

The steady-state arterial CO2 tension (PaCO2) was examined during control and intravenous CO2 loading in awake dogs unencumbered by any breathing apparatus. The dogs inhaled air while undergoing intravenous CO2 loading, and we estimated the gain, delta VA/delta PACO2. CO2 was introduced into the systemic venous blood via a membrane gas exchanger in a femoral arteriovenous shunt circuit, and the extracorporeal blood flow was maintained constant at 0.5 l/min. A total of 11 experiments were performed in 3 dogs comprising 93 control observations and 83 CO2 loading observations. Intravenous CO2 produced a significant increase in the steady state PaCO2, a finding consistent with our previous study in tracheostomized awake dogs. We conclude that intravenous CO2 produces hypercapnia in the awake dog with an intact airway unencumbered by external respiratory apparatus.

Acidosis, Respiratory↗
PubMed1978

Respiratory responses to intravenous and intrapulmonary CO2 in awake dogs.

Ventilatory responses to CO2 inhalation and CO2 infusion were compared in the awake dog. The CO2 was introduced directly into the systemic venous blood via a membrane gas exchanger in a femoral arteriovenous shunt circuit, and the extracorporeal blood flow, QX, was maintained constant at one of two rates: low, 0.5 l/min; or high, 2.0 l/min. A total of 13 experiments was performed in four dogs comprising 50 control and 25 inhalation and infusion observations at each of the two flow rates. Comparison of CO2-response curve slopes, S = delta V E/delta PaCO2, between CO2 inhalation and infusion showed no significant difference either within or between flow rates. The mean value of S for all conditions was 1.88 l/min per Torr with a 95% confidence interval of 1.66 -2.14. An independent additive ventilatory drive amounting to 28% of low-flow control VE was found at the highflow rate. We conclude that at constant blood flow the responses to both CO2 inhalation and infusion are hypercapnic and not significantly different.

Animals↗
PubMed1977

Mechanism of respiratory responses to intravenous NaHCO3, HCl, and KCN.

We studied the mechanism by which respiratory responses are produced by rapid injection of NaHCO3, HCl, or KCN into the superior vena cava of lightly anesthetized dogs. To estimate independently circulatory transit time to receptor sites, the solutions were injected at 0 degrees C and their arrival time at the ascending aorta and carotid sinus was detected by thermocouples. All of the ventilatory responses were observed to begin after the substances had reached the ascending aorta and 94% began after the carotid sinus had been reached. The injections were repeated following bilateral vagotomy and/or carotid body resection. Vagotomy produced no significant changes in ventilatory responses, but carotid body resection considerably reduced them. Following both procedures, few ventilatory responses were observed, and the time lag to the onset of the response increased greatly. We conclude that all of the observed ventilatory responses can be accounted for by the known arterial and central chemoreceptors, and that no evidence for pulmonary chemoreceptors was obtained.

Animals↗