Gas bubbles in the circulation of divers after ascending excursions from 300 to 250 msw.

The occurrence of intravascular bubbles in arteries and veins has been studied using pulsed Doppler ultrasound in six subjects who performed two ascending excursions each from 300 to 250 meters of seawater (msw) during a heliox saturation dive. Following decompression, high-intensity reflections could be observed not only in the venous system but also in the arteries, most notably in the carotid artery. Intravascular bubbles were more numerous during the first ascent than during the second.

Alterations in red blood cell morphology during a 500 metre dive.

Following compression to 500 m in a simulated chamber dive, the blood samples of the six divers were all found to contain several types of non-discoid erythrocytes. Compression to this depth induced a pressure stress and sensitisation in a proportion of each divers' erythrocyte population. Long in vitro decompression procedures further stressed these red cells and resulted in additional morphological changes.

Effect of 71 ATA He-O2 on organ blood flow in the rat.

Cardiac output and organ blood flow to major organs were investigated in awake rats at 1 atmosphere absolute (ATA) air and at 71 ATA He-O2. Radioactively labeled microspheres [15 +/- 1 (SD) micron] were injected into the left ventricle during constant-rate arterial blood sampling at 1 ATA air and subsequently at 71 ATA He-O2. Intra-arterial blood pressure was continuously recorded.

Heat loss and tolerance time during cold exposure in heliox atmosphere at 16 ATA.

Four different types of protective clothing and three different methods of heat conservation protection were evaluated during an exposure to 4 degrees C cold in a heliox atmosphere at 150 msw. The divers using protective systems with little insulation had to quit the test after 1-2 h due to uncontrollable shivering and an extreme feeling of cold, whereas the divers using the heavily insulated clothing were able to stay in the chamber for 8-10 h. However, even with adequate protection against convective heat loss from the skin, respiratory convective heat loss will be high unless inspired gas is heated.

Neurotensin-induced increase in intestinal blood flow in the anesthetized rat.

Cardiac output (CO) and blood flow to major organs were investigated in pentobarbital-anesthetized rats using 85Sr and 141Ce labelled microspheres (MS) of 15 microns diameter injected into the left ventricle. Changes in organ blood flow and CO were measured after intraventricular dextran (3.4 mumol/kg/min) and intravenous neurotensin (NT) at two different rates, 2.