Restoration of hemodynamics in apnea struggle phase in association with involuntary breathing movements
| Autor: | Zeljko Dujic, Vladimir Ivancev, Darija Bakovic, Ante Obad, J. Kevin Shoemaker, Davor Eterović, Zoran Valic, Ivan Palada |
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| Rok vydání: | 2008 |
| Předmět: |
Adult
Male Pulmonary and Respiratory Medicine Apnea Inferior vena cava Ultrasound Human Cardiac output Physiology Diving Hemodynamics Cardiovascular Physiological Phenomena Humans Medicine Lung volumes Cardiac Output Photoplethysmography Pulmonary Gas Exchange business.industry General Neuroscience Muscle Smooth Stroke volume Adaptation Physiological medicine.vein Anesthesia Respiratory Mechanics Breathing medicine.symptom business Venous return curve |
| Zdroj: | Respiratory Physiology & Neurobiology. 161:174-181 |
| ISSN: | 1569-9048 |
| DOI: | 10.1016/j.resp.2008.01.008 |
| Popis: | Involuntary breathing movements (IBM) that occur in the struggle phase of maximal apneas produce waves of negative intrathoracic pressure. This could augment the venous return, increasing thereby the cardiac output and gas exchange, and release the fresh blood from venous pools of spleen and liver. To test these hypotheses we used photoplethysmography and ultrasound for assessment of hemodynamics and spleen size before, during and after maximal dry apneas at large lung volume in 7 trained divers. During the easy-going phase cardiac output was reduced about 40%, due to reduction in stroke volume and in presence of reduced inferior vena cava venous return, while the spleen contracted for about 60 ml. Towards the end of the struggle phase, in presence of intense IBM, the spleen volume further decreased for about 70 ml, while cardiac output and caval flow almost renormalized. In conclusion, IBM coincide with splenic volume reduction and restoration of hemodynamics, likely facilitating the use of the last oxygen reserves before apnea cessation. |
| Databáze: | OpenAIRE |
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