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J Holthaus

Publications and source records attributed to J Holthaus.

4 recordsLinked to original sources
PubMed1997

Effects of a single saturation dive on lung function and exercise performance.

We studied the effects of an experimental saturation dive to 360 and 450 m in a simulation chamber on spirometric lung function, diffusing capacity, pulmonary compliance, and exercise performance in eight professional divers (age 22-40 years). To assess intraindividual variability, all parameters were measured on 2 days before and on 2 consecutive days immediately after the dive. For the group as a whole there was a significant increase in vital capacity and alveolar volume, and a decrease in Krogh factor and specific compliance (P < 0.01). These changes were reduced on the 2nd day after the dive. All subjects showed lowered exercise performance after the dive. Arterial pressure of oxygen and ventilation during exercise increased (P < 0.01), whereas arterial pressure of carbon dioxide, oxygen uptake, and anaerobic threshold decreased (P < 0.01). Exercise parameters showed only a slight trend towards pre-dive values on the 2nd day after a dive. The individual analysis revealed that after the dive two subjects showed a marked decrease in diffusing capacity and a more than average decrease in Krogh factor (TLCO/VA). One of them had signs of mild decompression sickness and the other, signs of pre-existing obstructive airways disease. Our data are compatible with the hypothesis that the effects of a single deep saturation dive on pulmonary function and exercise performance are the results of counteracting mechanisms. We suggest that lung volumes increase due to the enhanced work of breathing during a deep saturation dive and that these changes could mask an impairment in gas exchange. Furthermore, a saturation dive can induce an apparent deterioration of pulmonary function.

Adult↗
PubMed1992

Urinary vasopressin and aldosterone and plasma volume during a saturation dive to 450 m.

Urinary vasopressin (VP), aldosterone (ALDO), osmotic substances, sodium excretion, and plasma volume were assessed in 4 healthy male divers during 2 predive control days, 2 compression days, 6 days at 46 atm abs, and 26 days of decompression with stops at 37 and 27 atm abs. At pressure the ambient gas was trimix (0.5 atm abs O2:5% N2:remainder He). All urine was collected throughout the dive. Samples were divided into daytime (0700-1900) and nighttime (1900-0700). Indocyanine green dye dilution was used to determine plasma volume at predive 1, 46, and 24 atm abs. In agreement with previous dives at 31 atm abs, there was a decrease in VP excretion during compression lasting until return to 1 atm abs (P less than 0.05). Also similar to the shallower dives at 31 atm abs, the normal diurnal pattern of VP excretion, daytime higher than nighttime (P less than 0.05), disappeared at pressure. Urine osmolality showed alterations compatible with responses to VP. In contrast to previous studies at 31 atm abs, but in agreement with a previous study at 49.5 atm abs, there was no sustained increase in urinary ALDO excretion and only a transient natriuresis during the compression phase, followed by a reduced sodium excretion. In confirmation of earlier conclusions from indirect evidence, direct measurements of plasma volume indicated a reduction of about 20% (P less than 0.05) at 46 atm abs which remained reduced after decompression to 24 atm abs.

Adult↗
PubMed1992

Platelet count in deep saturation diving.

Platelet counts were measured in 10 divers during the course of 4 experimental deep dives (450 and 600 m) and different anticoagulants were tested. The use of sodium citrate as an anticoagulant was associated with artifactual thrombocytopenia, whereas ethylenediaminetetraacetic acid proved to be satisfactory. During one of the dives (450 m) the use of fluorocarbon to remove excess dissolved inert gas before decompression of the samples was systematically tested. Mean platelet count decreased from 272,600 +/- 29,400 mm-3 (mean +/- SD) on Day 7 (450 m) to 177,700 +/- 26,400 mm-3 on Day 12 (360 m). Platelet count had recovered to 209,900 +/- 20,700 mm-3 at the time of surfacing. Mean hematocrit (expressed in percent) increased from 44.7 +/- 2.2 predive to 59.4 +/- 2.0 on Day 7 (450 m) to 40.9 +/- 2.8 at the time of surfacing. These changes were statistically significant (P less than 0.05). Platelet counts on samples that had been degassed with fluorocarbon were not different from samples that had been decompressed without degassing.

Citrates↗