PubMed Health⌕ Search

Biomedical subjects

B J Kirby

Publications and source records attributed to B J Kirby.

15 recordsLinked to original sources
PubMed1992

The influence of the site of sampling and assay medium upon the measurement and interpretation of blood lactate responses to exercise.

UNLABELLED: This paper reports the findings of two investigations into methodological problems associated with the interpretation of blood lactate (BLa) in the sports sciences. In Experiment 1, brachial artery (A), antecubital venous (V) and fingertip capillary (C) blood samples were drawn simultaneously from nine subjects (mean age 21.1 +/- 1.3 years) during an incremental treadmill protocol and immediately assayed for BLa concentration. Experiment 2 investigated the extent of lactate concentration differences in whole blood (WB), lysed blood (LB) and plasma (P) measured using a YSI 23 AM analyser. In Experiment 1, a comparison of the mean BLa concentrations obtained from the three sites revealed no significant differences (P greater than 0.05). Correlations between BLa samples from different sites were very high, with r values ranging from 0.858 to 0.983. In Experiment 2, the mean lactate concentrations were: WB, 4.7 +/- 2.7 mM; LB, 5.0 +/- 3.0 mM; P, 7.0 +/- 3.8 mM. Plasma (P) values were significantly higher than WB and LB. Values from all sites were highly correlated with coefficients ranging from 0.963 to 0.987. IN CONCLUSION: (1) Significant arterial and venous BLa concentration differences do not exist during incremental treadmill exercise. (2) As capillary BLa concentrations reflect arterial values, their use in laboratory and field settings is recommended. (3) Lactate concentration differences in whole blood, lysed blood and plasma will influence the assessment of performance at fixed lactate reference values. (4) If the inter-laboratory test procedures are to be standardized and results compared, precise reporting of lactate sampling and assay techniques is critical.

Adult↗
PubMed1977

Circulatory reflexes in myocardial infarction.

The Valsalva manoeuvre was used to examine circulatory reflexes in 22 patients with acute myocardial infarction. Four patients had the 'square wave' response of cardiac failure and two responded normally to the manoeuvre. In the remaining 18 patients there was a 20 per cent or more fall in pulse pressure during the manoeuvre, but no ensuing rise in diastolic pressure, implying impairment of vasoconstriction. This impairment cannot be explained by acidosis, hypocapnia, or arterial hypoxaemia but may be explained by reflex inhibition of vasoconstriction. This abnormal response has important implications when transporting patients; furthermore, it could explain the rapid deterioration sometimes seen in patients with arrhythmias.

Adult↗
PubMed1976

Prognosis of new and worsening angina pectoris.

The natural history of new and worsening angina pectoris was studied in 251 men aged under 70 years. Most were ambulant and all were referred by selected general practitioners to a special hospital clinic over two and a half years. Heart attacks developed in 39 patients, nine of whom died. Seventy-two per cent of the attacks occurred within six weeks of the onset or worsening of angina. Of the 212 patients who did not suffer myocardial infarction and who were clinically reviewed six months after their first attendance 66 had been pain free for the previous three months and 14 had experienced only infrequent attacks of angina. Of the 128 men aged under 65 years who were previously in employment 81% had returned to full-time work six months after their first attendance. A discriminant function analysis using many variables was made to develop a predictive index that would allow patients with new or worsening angina who were likely to develop serious cardiac complications to be identified. This did not prove possible, and the only predictive factor of significance was an increased cardiothoracic ratio. The syndrome of new and worsening angina has a low risk of early death, and many patients are symptom free six months later. In general, emergency coronary arteriography and surgery is not indicated.

Adult↗
PubMed1976

Long-term domiciliary oxygen therapy in cor pulmonale complicating chronic bronchitis and emphysema.

Ten patients with cor pulmonale complicating severe chronic bronchitis and emphysema have been treated with 2 litres/min of oxygen for prolonged periods in the day, at home, over 12 to 62 months. Two patients died after 12 and 36 months of treatment. Pulmonary arterial pressure was reduced in seven patients, and red cell mass in eight, when the oxygen was given for over 15 hours in the day. Hospital inpatient treatment was greatly reduced following the start of long-term oxygen treatment in all patients. This treatment is expensive, and a controlled trial is necessary to establish its definitive place and cost-effectiveness, but the results of such a current Medical Research Council trial will not be available for a further two years.

Aged↗
PubMed1975

A double-blind trial of patient-controlled nitrous-oxide/oxygen analgesia in myocardial infarction.

The analgesic effect of self-administered nitrous oxide 50%/oxygen 50% ('Entonox" analgesic apparatus) was compared with air given by the same method in a double-blind trial in 81 patients with myocardial infarction. Self-administered nitrous oxide/oxygen, which was associated with a low frequency of side-effects, proved significantly more effective than air in the early relief of severe cardiac pain, but not in the relief of moderate or slight pain or when administration was continued after ten minutes.

Adult↗
PubMed1975

Changes in haemoglobin binding curve and oxygen transport in chronic hypoxic lung disease.

Direct measurements of the factors determining blood oxygen transport in 10 patients with chronic hypoxic respiratory failure led to the conclusion that wide differences in the position of their oxygen binding curves, due to spontaneous differences in red-cell 2, 3-diphosphoglycerate, had little effect on oxygen delivery to the tissues, as assessed by the mixed venous oxygen tension when they were breathing air. This result arises from the shape of the oxygen binding curve. A drug which could shift the curve to the right would help tissue oxygenation in cardiogenic and other forms of shock, when a low cardiac output can not be improved though arterial blood can be well oxygenated.

Cardiac Output↗
PubMed1975

Arterial catecholamines in hypoxic exercise in man.

1. We measured the minute ventilation and arterial blood catecholamine concentrations in four normal men standing and at two levels of moderate treadmill exercise breathing 14% oxygen or air. 2. Minute ventilation was significantly higher during hypoxic exercise than during normoxic exercise at an oxygen uptake of 1500 ml/min. 3. Arterial plasma noradrenaline during hypoxic exercise at an oxygen uptake of 1500 ml/min was significantly greater than at rest. 4. Arterial plasma noradrenaline during normoxic exercise at an oxygen uptake of 1500 ml/min was not elevated above the resting concentration. 5. The results are compatible with the suggestion that increased concentrations of arterial plasma noradrenaline contribute to the hypoxic potentiation of the respiratory response to moderate exercise.

Adult↗
PubMed1975

Cardiorespiratory effects of rapid saline infusion in normal man.

We have studied the cardiorespiratory effects of the rapid infusion (100 ml/min) of 2 liters of saline in four normal seated subjects. Cardiac output and pulmonary arterial pressure increased, while vital capacity (VC) and total lung capacity (TLC) decreased. There was an increase in closing volume (CV) without any detectable change in lung compliance or flow-volume characteristics. There was an increase in Pao2 during infusion period which can be related to better matching of ventilation to perfusion and to improved hemoglobin transport. In the recovery stage as cardiac output, pulmonary arterial pressure, TLC, and VC all returned toward control values CV remained high. In two subjects CV occurred within the normal tidal range of ventilation and in these two subjects Pao2 fell significantly below values obtained in the control period. The results suggest that rapid saline infusion in man can cause interstitial edema and lead to premature airway closure and hypoxemia.

Airway Resistance↗
PubMedDate not supplied

Venous carbon dioxide tensions in chronic obstructive lung disease.

Eighteen patients with severe chronic obstructive lung disease (arterial PCO2 greater than 45 mmHg arterial PCO2 less than 55 mmHg) were studied during a stable period of their disease. Samples of arterial blood and blood from the main pulmonary artery, internal jugular vein, hepatic vein, renal vein and femoral vein were taken by manipulating a Cournand catheter to each of these sites in rapid succession. An estimate of the regional distribution of blood flow was derived from the arterio-venous oxygen content difference of each organ. Expired air was collected into a spirometer. There was a redistribution of blood flow in these patients with chronic lung disease in accord with the observations made by others in the past. Carbon dioxide concentration in the venous blood depends on 1. the blood flow to an organ, and 2. the carbon dioxide production by the organ. The total body CO2 production was within normal limits and there is no reason to suspect any alteration in carbon dioxide production by individual organs in these resting patients. Thus the venous CO2 levels are intimately linked with organ blood flow but even a substantial increase in organ blood flow cannot always compensate for the disorder in the lung. The exact role of CO2 in regulating the peripheral circulation cannot be assessed from this study but they do emphasize the importance of regional blood flow in regulating the concentration of CO2 in the venous blood and presumably in the tissues making up the organ.

Aged↗