The human spleen as an erythrocyte reservoir in diving-related interventions

• Published in: Journal of applied physiology (1985) 2002-05, Vol.92 (5), p.2071-2079
• Main Authors: Espersen, Kurt, Frandsen, Hans, Lorentzen, Torben, Kanstrup, Inge-Lis, Christensen, Niels J
• Format: Article
• Language: English
• Subjects: Adult; Apnea - physiopathology; Applied physiology; Biological and medical sciences; Blood Volume - physiology; Diving; Diving - physiology; Epinephrine - blood; Erythrocyte Volume; Erythrocytes; Erythrocytes - physiology; Fundamental and applied biological sciences. Psychology; Hematocrit; Hemodynamics - physiology; Hemoglobins - analysis; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Male; Medical sciences; Norepinephrine - blood; Radionuclide Imaging; Spleen; Spleen - diagnostic imaging; Spleen - physiology; Transports. Aerospace. Diving. Altitude; Ultrasonography; Vertebrates: blood, hematopoietic organs, reticuloendothelial system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00055.2001

Departments of 1  Clinical Physiology and Nuclear Medicine and 2  Ultrasound and 3  Division of Endocrinology, Herlev Hospital, University of Copenhagen, DK-2730 Herlev, Denmark Twelve subjects without and ten subjects with diving experience performed short diving-related interventions. After labeling of erythrocytes, scintigraphic measurements were continuously performed during these interventions. All interventions elicited a graduated and reproducible splenic contraction, depending on the type, severity, and duration of the interventions. The splenic contraction varied between ~10% for "apnea" (breath holding for 30 s) and "cold clothes" (cold and wet clothes applied on the face with no breath holding for 30 s) and ~30-40% for "simulated diving" (simulated breath-hold diving for 30 s), "maximal apnea" (breath holding for maximal duration), and "maximal simulated diving" (simulated breath-hold diving for maximal duration). The strongest interventions (simulated diving, maximal apnea, and maximal simulated diving) elicited modest but significant increases in hemoglobin concentration (0.1-0.3 mmol/l) and hematocrit (0.3-1%). By an indirect method, the splenic venous hematocrit was calculated to 79%. No major differences were observed between the two groups. The splenic contraction should, therefore, be included in the diving response on equal terms with bradycardia, decreased peripheral blood flow, and increased blood pressure. splenic contraction; splenic venous hematocrit; simulated diving; diving response