Haemodynamic and metabolic studies in man with special reference to the effects of oxygen

Abstract Not Provided

Influence of oxygen tension on myocardial performance. Evaluation by tissue Doppler imaging

BACKGROUND: Low O(2 )tension dilates coronary arteries and high O(2 )tension is a coronary vasoconstrictor but reports on O(2)-dependent effects on ventricular performance diverge. Yet oxygen supplementation remains first line treatment in cardiovascular disease. We hypothesized that hypoxia improves and hyperoxia worsens myocardial performance. METHODS: Seven male volunteers (mean age 38 ± 3 years) were examined with echocardiography at respiratory equilibrium during: 1) normoxia (≈21% O(2), 79% N(2)), 2) while inhaling a hypoxic gas mixture (≈11% O(2), 89% N(2)), and 3) while inhaling 100% O(2). Tissue Doppler recordings were acquired in the apical 4-chamber, 2-chamber, and long-axis views. Strain rate and tissue tracking displacement analyses were carried out in each segment of the 16-segment left ventricular model and in the basal, middle and apical portions of the right ventricle. RESULTS: Heart rate increased with hypoxia (68 ± 4 bpm at normoxia vs. 79 ± 5 bpm, P < 0.001) and decreased with hyperoxia (59 ± 5 bpm, P < 0.001 vs. normoxia). Hypoxia increased strain rate in four left ventricular segments and global systolic contraction amplitude was increased (normoxia: 9.76 ± 0.41 vs hypoxia: 10.87 ± 0.42, P < 0.001). Tissue tracking displacement was reduced in the right ventricular segments and tricuspid regurgitation increased with hypoxia (7.5 ± 1.9 mmHg vs. 33.5 ± 1.8 mmHg, P < 0.001). The TEI index and E/E' did not change with hypoxia. Hyperoxia reduced strain rate in 10 left ventricular segments, global systolic contraction amplitude was decreased (8.83 ± 0.38, P < 0.001 vs. normoxia) while right ventricular function was unchanged. The spectral and tissue Doppler TEI indexes were significantly increased but E/E' did not change with hyperoxia. CONCLUSION: Hypoxia improves and hyperoxia worsens systolic myocardial performance in healthy male volunteers. Tissue Doppler measures of diastolic function are unaffected by hypoxia/hyperoxia which support that the changes in myocardial performance are secondary to changes in vascular tone. It remains to be settled whether oxygen therapy to patients with heart disease is a consistent rational treatment

The diagnostic value of the Grünbaum-Widal reaction in typhoid fever, in various infective and non-infective conditions, and in health.

The subject of Typhoid'Never and the Serum Reaction so intimately associated with it has always been faseinating and interesting. It is still more so when one realises that the so called Serum Reaction in Typhoid Never is very occasionally wrong, being sometimes absent in Typhoid Never and more often, though still seldom, present in other diseases.To investigate this subject has been my desire and my chief object in working with the Serum Reaction was to find out if this trace of error was constant or if in all cases of Typhoid Never the Serum gave the Aggliininative Reaction, and so to prove the value of the test. The observations were carried out amongst four classes of patients and included 255 cases with 855 observations: -1st Those suffering from or who had suffered from Nnteric Never;2nd Those suffering from diseases resembling Enteric, but in whom the Diagnosis clinically was uncertain.3rd Those suffering from or convalescent from other diseases belonging mainly to the infective group.4th Normal healthy people.The results of my observations are given in Tables situated at the end of the Volume. Those.relating to the group of various diseases have "been typed, whilst for the sake of ease in examination the tabular results belonging to the Enteric group have been drawn out by hand