Microwave warming of 1.5% glycine solution.

The urological irrigating fluid 1.5% glycine is routinely warmed in specifically designed warming drawers prior to use. This study shows that the use of microwave energy to achieve body temperature in 2-litre bags of glycine solution is biochemically safe and that the sterility of the solution is maintained. There is a linear relationship between the temperature of the solution and time in the microwave oven, so allowing a simple formula to predict the correct heating time given variable ambient starting temperatures.

Regional alveolar gas composition and lung function in sheep.

The influence of regional alveolar oxygen and carbon dioxide tensions on the distribution of lung blood flow and gas exchange was studied in unanaesthetised sheep. Right apical lobe (RAL) hypoxia, induced by administering nitrogen or nitrogen/oxygen mixtures to the lobe, stimulated a prompt, graded and well sustained reduction in lobar blood flow. Maximum hypoxia was accompanied by an approximate 65% reduction in perfusion, a significant fall in RAL carbon dioxide tension and output, a reversal of lobar oxygen flux and an average 13 Torr fall in arterial oxygen tension. The reduction in perfusion and gas exchange persisted in the face of elevated systemic oxygen tensions produced by giving pure oxygen instead of air to the remainder of the lung (RL). Mild RAL hypercapnia potentiated the hypoxia-induced change in perfusion and gas exchange. During lobar hypoxia RL blood flow and gas exchange increased to maintain total pulmonary gas exchange at an essentially constant level. RAL hyperoxia did not significantly alter the distribution of perfusion or gas exchange.

Oculoplethysmography and carotid phonoangiography for the noninvasive detection of extracranial carotid occlusive disease.

Clinical applications of imaging techniques and noninvasive physiological vascular evaluations provide useful assistance in the detection and management of stroke-prone patients by minimizing unnecessary carotid arteriography and surgery. Two such evaluation techniques are oculoplethysmography (OPG) and carotid phonoangiography (CPA). Developed, used, and proved highly reliable at the Tucson (Arizona) Medical Center, the techniques have been documented in 12,000 tests on approximately 8500 patients. OPG simultaneously records the bilateral ocular pulses concomitantly with external carotid pulses. Delays in timing of these pulses reflect reduction of flow in the internal and/or external carotid arteries, respectively. CPA consists of electronic stethoscopic auscultation, direct visualization, and photographic recording of carotid bruits or blood flow sounds.

An animal model for the study of regional lung function.

An animal model for the study of regional lung function is described. In sheep, the bronchus to the right apical lobe (RAL) of the lung arises directly from the trachea. A tracheal divider, inserted under local anesthesia via a permanent tracheostomy, was used to separate the ventilation of the RAL from that of the rest of the lung. Lobar blood flow was estimated from the RAL contribution to the pulmonary clearance of an intravenous bolus of 85Kr. Gas exchange was measured by conventional methods. Expressed as a percentage of the value obtained for the whole lung, lobar expired volume was 14.7 +/- 4.3%, capillary perfusion was 12.3 +/- 4.2%, oxygen uptake was 14.7 +/- 4.9%, and carbon dioxide production was 13.4 +/- 5.5% (mean +/- SD of 25 studies in 11 animals breathing air). The model permits the study of experimental conditions confined to a single lobe of the lung and offers the advantages of an intact chest wall, spontaneous ventilation and an unanesthetized animal.