Haematology studies during a 350‐metre dive

Abstract

Routine haematological monitoring of 6 deep‐sea divers was performed pre‐dive, during the three phases of the 350 m working dive, and at two post‐dive medical examinations. In the compression phase a small percentage (< 5%) of each subject's red cells became non‐discoid in shape and this trend continued during the 6 d at 350 m. Concomitantly each subject was mildly dehydrated by compression diuresis and had a raised haematocrit (+ 5%); all other haematological parameters remained within normal limits. The number of morphologically aberrant cells continued to increase during decompression but were not present at the 1 month post‐dive medical examination. The subjects' mean relative reticulocyte number was decreased during the dive to 0.4%, showing a rapid and sustained increase to 2.1% at both post‐dive examinations. The red cell count was reduced by 10% during the course of the dive. Hb concentration and haematocrit evidenced no differences between the pre‐ or postdive measurements.

Hematocrit Change in Tropical Scuba Divers☆

“…Yet although increased ANP levels have been demonstrated in both deep chamber 8 and shallow water immersion 9 settings and have been associated with increased urine flow, the evidence for an accompanying increase in Ht is inconclusive. Previous studies reporting the Ht response to diving interventions have featured prolonged immersions, 10 repetitive breath-hold diving series, 11 high absolute pressures, 12 and dry chamber environments 13 ; some of these studies have observed Ht increases of 5% to 10%; others have reported no significant evidence of a change, but none can be said to have replicated the typical scuba diving experience.…”