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Biomedical subjects

P C Gordon

Publications and source records attributed to P C Gordon.

54 records · Page 3Linked to original sources
PubMed1992

Anaesthesia for liver transplantation. The Groote Schuur Hospital experience.

In October 1988 the orthotopic liver transplantation programme recommenced at Groote Schuur Hospital. The experience gained from our first 10 patients is described here. Anaesthesia for this type of surgery is demanding given the long duration of the operation and the severe haemodynamic and physiological alterations that can occur. A rapid sequence induction is usually performed and anaesthesia maintained with fentanyl and isoflurane. Dopamine and mannitol are used for renal protection. Extensive monitoring of haemodynamics, biochemistry, coagulation and temperature is essential. A rapid infusion device is mandatory as massive blood loss may occur. All patients were electively ventilated in the surgical intensive care unit postoperatively. One patient died 11 days postoperatively. The remainder are well at the time of writing.

Anesthesia↗
PubMed1991

Predictors of event-free survival after balloon aortic valvuloplasty.

BACKGROUND: Balloon aortic valvuloplasty was developed as an alternative to aortic-valve replacement in selected elderly patients with aortic stenosis. The use of this procedure is limited, however, by a high incidence of restenosis. METHODS: Between December 1985 and April 1989, valvuloplasty was performed in 205 patients. We evaluated 40 demographic and hemodynamic variables as univariate predictors of event-free survival by Cox regression analysis and identified independent predictors of event-free survival by stepwise multivariate analysis. RESULTS: Early hemodynamic results indicated a decrease in the peak transaortic-valve pressure gradient from 67 +/- 28 to 33 +/- 15 mm Hg after valvuloplasty and an increase in aortic-valve area from 0.6 +/- 0.2 to 0.9 +/- 0.3 cm2 (P less than 0.001 for both comparisons). The rate of event-free survival (defined as survival without recurrent symptoms, repeated valvuloplasty, or aortic-valve replacement) was 18 percent over the mean (+/- SD) follow-up period of 24 +/- 12 months (range, 1 to 47). Significant predictors of event-free survival included the left ventricular ejection fraction and the left ventricular and aortic systolic pressure before valvuloplasty, and the percent reduction in the aortic-valve pressure gradient; the pulmonary-capillary wedge pressure was inversely associated with event-free survival. Although the predicted event-free survival rate for the entire patient group was 50 percent at one year (95 percent confidence interval, 43 to 57 percent) and 25 percent at two years (95 percent confidence interval, 19 to 31 percent), the probability of event-free survival at one year varied between 23 and 65 percent when patients were stratified according to three independent predictors: the aortic systolic pressure, the pulmonary-capillary wedge pressure, and the percent reduction in the peak aortic-valve gradient. CONCLUSIONS: The most important predictors of event-free survival after balloon aortic valvuloplasty were related to base-line left ventricular performance. The best long-term results after valvuloplasty were observed among patients who would also have been expected to have excellent long-term results after aortic-valve replacement.

Aortic Valve Stenosis↗
PubMed1989

Context effects in recognizing syllable-final /z/ and /s/ in different phrasal positions.

An examination of the effect of phrase-final lengthening on the temporal correlates of voicing in syllable-final /s/ and /z/ was conducted. Discriminant analyses revealed that a combination of vowel duration, frication duration, and the duration of simultaneous voicing and frication was quite successful in determining voicing independently of phrase-final lengthening. Two perceptual experiments revealed that human listeners' recognition of the segments does benefit from hearing the syllables in sentential context as opposed to when they are excised from context and presented in isolation. The benefit was greatest for /s/ in phrase-final position and /z/ in phrase-internal position. This suggests that the presence of sentential context allows listeners to factor out the influence of phrase-final lengthening on vowel duration and to more accurately interpret this cue to voicing of the final fricative. These findings extend previous results on rate-dependent processing of overall speaking rate to the processing of local speaking rate. By doing so, they provide further evidence of the importance of extended phonetic context in speech recognition.

Humans↗
PubMed1987

Effects of sleeping with the bed-head raised and of ranitidine in patients with severe peptic oesophagitis.

Sleeping with the bed-head raised is commonly recommended as treatment for patients with troublesome oesophagitis, but its effect has not been objectively tested. Ranitidine therapy is useful in oesophagitis, but it does not often produce complete relief of symptoms. The effects of each of these treatments alone and in combination have been studied in 71 patients with severe (grade III) peptic oesophagitis. Each treatment improved both symptoms and endoscopic appearances significantly more than placebo did. However, the combination of the two treatments was much better than either alone; the reduction in pain score and the area of ulceration healed were about twice those with either treatment alone. Smoking more than five cigarettes per day or drinking more than 30 g alcohol per day significantly reduced the effectiveness of ranitidine therapy, but age, sex, body weight, or the presence of a hiatus hernia had no detectable effect.

Adult↗
PubMed1984

Perceptual-motor processing of phonetic features in speech.

Some reaction time experiments are reported on the relation between the perception and production of phonetic features in speech. Subjects had to produce spoken consonant-vowel syllables rapidly in response to other consonant-vowel stimulus syllables. The stimulus syllables were presented auditorily in one condition and visually in another. Reaction time was measured as a function of the phonetic features shared by the consonants of the stimulus and response syllables. Responses to auditory stimulus syllables were faster when the response syllables started with consonants that had the same voicing feature as those of the stimulus syllables. A shared place-of-articulation feature did not affect the speed of responses to auditory stimulus syllables, even though the place feature was highly salient. For visual stimulus syllables, performance was independent of whether the consonants of the response syllables had the same voicing, same place of articulation, or no shared features. This pattern of results occurred in cases where the syllables contained stop consonants and where they contained fricatives. It held for natural auditory stimuli as well as artificially synthesized ones. The overall data reveal a close relation between the perception and production of voicing features in speech. It does not appear that such a relation exists between perceiving and producing places of articulation. The experiments are relevant to the motor theory of speech perception and to other models of perceptual-motor interactions.

Adaptation, Physiological↗
PubMed1971

The probability of death following a fracture of the hip.

All patients 45 years of age and over admitted with fractures of the hip to hospitals in the Atlantic Health Region of Nova Scotia were followed up over a two-year period. Actuarial methods were used to estimate survivorship from the date of fracture in 202 patients.Over-all, it was estimated that only 63.8% would be alive by one year post-fracture. This is 70% of the survival rate expected in the general population of corresponding age and sex. The period of greatest mortality was within the first 12 weeks. Patients surviving to one year could be considered "cured", for after that their survivorship was at least as favourable as that of the "normal" population.Mortality was greatest in males in those 75 years of age and over and especially in patients who were relatively immobilized prior to their fracture. In this "dependent" group the relative survival ratio at one year was only 38%.

Adult↗
PubMed1966

An approach to patient care classification.

Employing the principles of progressive patient care and using data obtained from charts, nurses and resident physicians, 265 patients on the wards of a teaching hospital were classified into one of six optimal levels of care by the resident physicians and also by an outside observer. It was assumed that facilities for the three alternatives to general hospital care, i.e. long-term hospital care, nursing care and sheltered care, were available in the community. It was also assumed that socio-economic factors presented no barrier to hospital discharge.The outside observer allocated 96 patients, approximately one-third, to the alternative facilities outside the general hospital. Those factors found to have statistically significant effects on assigned levels of care were the diagnoses, length of stay, region of residence, bed status, extent of nursing care, hospital service and discharge status. The residents allocated 60 patients, approximately one-fifth, to alternative facilities.The extent of agreement between the residents and the outside observer reached 81% for those to alternate versus general hospital care.This method could be used by nurses and residents to screen out those most suitable for care in alternate facilities.

Humans↗
PubMed1966

The epidemiology of cerebral vascular disease in Canada: an analysis of mortality data.

Mortality data for cerebral vascular disease in Canada and its provinces were analysed as an initial approach to the understanding of the epidemiology of this disease. Since 1950, there has been a decline in mortality attributed to vascular lesions of the central nervous system. This decline has been more pronounced in females. Five-year average age-sex-specific rates (1960-64) showed an almost constant proportional increase with age. The highest mortality rates tended to occur in the Eastern Provinces.From 1950 to 1964 there was a 21% decline in mortality due to intracranial hemorrhage and a concomitant 53% decline in mortality attributed to hypertensive disease. Over the same period there was a 24% increase in mortality attributed to cerebral embolism and thrombosis, and an 8% increase in mortality due to arteriosclerotic heart disease. Areal correlations offered only inconsistent support for the hypothesis that these associated trends are due to common etiologic determinants.Evidence presently available does little to clarify to what extent these trends and differences can be attributed to coding, certification and diagnostic practices, and to what extent to changing and differing incidence and prognosis.

Adult↗