title: Influence of Apnea-induced Hypoxia on Catecholamine Release and Cardiovascular Dynamics.
abstract: Prolonged breath-hold causes complex compensatory mechanisms such as increase in blood pressure, redistribution of blood flow, and bradycardia. We tested whether apnea induces an elevation of catecholamine-concentrations in well-trained apneic divers.11 apneic divers performed maximal dry apnea in a horizontal position. Parameters measured during apnea included blood pressure, ECG, and central, in addition to peripheral hemoglobin oxygenation. Peripheral arterial hemoglobin oxygenation was detected by pulse oximetry, whereas peripheral (abdominal) and central (cerebral) tissue oxygenation was measured by Near Infrared Spectroscopy (NIRS). Exhaled O2and CO2, plasma norepinephrine and epinephrine concentrations were measured before and after apnea.Averaged apnea time was 247±76 s. Systolic blood pressure increased from 135±13 to 185±25 mmHg. End-expiratory CO2increased from 29±4 mmHg to 49±6 mmHg. Norepinephrine increased from 623±307 to 1 826±984 pg ml-1and epinephrine from 78±22 to 143±65 pg ml-1during apnea. Heart rate reduction was inversely correlated with increased norepinephrine (correlation coefficient -0.844, p=0.001). Central (cerebral) O2desaturation was time-delayed compared to peripheral O2desaturation as measured by NIRSabdominaland SpO2.Increased norepinephrine caused by apnea may contribute to blood shift from peripheral tissues to the CNS and thus help to preserve cerebral tissue O2saturation longer than that of peripheral tissue.
authors.affiliation: Klinik und Poliklinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Eichhorn
authors.affiliation: Klinik und Poliklinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Erdfelder
authors.affiliation: Klinik und Poliklinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Kessler
authors.affiliation: Institut für Klinische Chemie und Klinische Pharmakologie, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: Ramona C
authors.initials: RC
authors.lastname: Dolscheid-Pommerich
authors.affiliation: Institut für Klinische Chemie und Klinische Pharmakologie, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: Berndt
authors.initials: B
authors.lastname: Zur
authors.affiliation: Institut für Physiologie und Anatomie, Deutsche Sporthochschule Köln, Köln, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Hoffmann
authors.affiliation: Klinik und Poliklinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: R Ellerkmann
authors.initials: RE
authors.lastname: Ellerkmann
authors.affiliation: Physiologisches Institut 2, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Meyer
mesh_terms: D000328:Adult; D001049:Apnea / Q000097:blood*; D001794:Blood Pressure; D062485:Breath Holding; D002245:Carbon Dioxide / Q000032:analysis; D004242:Diving / Q000502:physiology; D004837:Epinephrine / Q000097:blood*; D005260:Female; D006339:Heart Rate; D006454:Hemoglobins; D006801:Humans; D000860:Hypoxia / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood*; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D019265:Spectroscopy, Near-Infrared
chemical_list: D006454:Hemoglobins; D002245:Carbon Dioxide; D010100:Oxygen; D009638:Norepinephrine; D004837:Epinephrine