Selected Contribution: Role of spleen emptying in prolonging apneas in humans.
Schagatay, Erika, Johan P. A. Andersson, Magnus Hallén, and Birger Pålsson.
1Department of Animal Physiology, Lund University, SE-223 62 Lund; 2Department
of Applied Natural Science, Mid Sweden University, 871 88 Härnösand; and
3Department of Surgery, Lund University Hospital, S-221 85 Lund, Sweden
APStracts 8:0043A, 2001.
This study addressed the interaction between short-term adaptation to apneas with face
immersion and erythrocyte release from the spleen. Twenty healthy volunteers, including
ten splenectomized subjects, participated. After prone rest, they performed five maximal-
duration apneas with face immersion in 10°C water, with 2-min intervals.
Cardiorespiratory parameters and venous blood samples were collected. In subjects with
spleens, hematocrit and hemoglobin concentration increased by 6.4% and 3.3%,
respectively, over the serial apneas and returned to baseline 10 min after the series. A
delay of the physiological breaking point of apnea, by 30.5% (17 s), was seen only in this
group. These parameters did not change in the splenectomized group. Plasma protein
concentration, preapneic alveolar «pco2», inspired lung volume, and diving bradycardia
remained unchanged throughout the series in both groups. Serial apneas thus triggered
the hematological changes that have been previously observed after long apneic diving
shifts; they were rapidly reversed and did not occur in splenectomized subjects. This
suggests that splenic contraction occurs in humans as a part of the diving response and
may prolong repeated apneas.
Received 10 October 2000; accepted in final form 16 January 2001
APS Manuscript Number A994-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 29 January 2001