Respiratory pump maintains cardiac stroke volume during hypovolemia in young, healthy volunteers
| Autor: | Maria Skytioti, Signe Søvik, Maja Elstad |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Male
medicine.medical_specialty Cardiac output Physiology Hypovolemia Hemodynamics Hemorrhage Positive-Pressure Respiration Young Adult 03 medical and health sciences 0302 clinical medicine Heart Rate 030202 anesthesiology Medisinske Fag: 700 [VDP] Physiology (medical) Intensive care Internal medicine Healthy volunteers Humans Medicine Arterial Pressure VDP::Medisinske Fag: 700 Artikkel Respiratory system Beneficial effects Lower Body Negative Pressure Blood Volume business.industry Respiration Cardiac stroke volume Heart Stroke Volume 030208 emergency & critical care medicine Healthy Volunteers Cardiology Female medicine.symptom business |
| ISSN: | 8750-7587 |
| Popis: | Spontaneous breathing has beneficial effects on the circulation, since negative intrathoracic pressure enhances venous return and increases cardiac stroke volume. We quantified the contribution of the respiratory pump to preserve stroke volume during hypovolemia in awake, young, healthy subjects. Noninvasive stroke volume, cardiac output, heart rate, and mean arterial pressure (Finometer) were recorded in 31 volunteers (19 women), 19–30 yr old, during normovolemia and hypovolemia (approximating 450- to 500-ml reduction in central blood volume) induced by lower-body negative pressure. Control-mode noninvasive positive-pressure ventilation was employed to reduce the effect of the respiratory pump. The ventilator settings were matched to each subject’s spontaneous respiratory pattern. Stroke volume estimates during positive-pressure ventilation and spontaneous breathing were compared with Wilcoxon matched-pairs signed-rank test. Values are overall medians. During normovolemia, positive-pressure ventilation did not affect stroke volume or cardiac output. Hypovolemia resulted in an 18% decrease in stroke volume and a 9% decrease in cardiac output ( P < 0.001). Employing positive-pressure ventilation during hypovolemia decreased stroke volume further by 8% ( P < 0.001). Overall, hypovolemia and positive-pressure ventilation resulted in a reduction of 26% in stroke volume ( P < 0.001) and 13% in cardiac output ( P < 0.001) compared with baseline. Compared with the situation with control-mode positive-pressure ventilation, spontaneous breathing attenuated the reduction in stroke volume induced by moderate hypovolemia by 30% (i.e., −26 vs. −18%). In the patient who is critically ill with hypovolemia or uncontrolled hemorrhage, spontaneous breathing may contribute to hemodynamic stability, whereas controlled positive-pressure ventilation may result in circulatory decompensation. NEW & NOTEWORTHY Maintaining spontaneous respiration has beneficial effects on hemodynamic compensation, which is clinically relevant for patients in intensive care. We have quantified the contribution of the respiratory pump to cardiac stroke volume and cardiac output in healthy volunteers during normovolemia and central hypovolemia. The positive hemodynamic effect of the respiratory pump was abolished by noninvasive, low-level positive-pressure ventilation. Compared with control-mode positive-pressure ventilation, spontaneous negative-pressure ventilation attenuated the fall in stroke volume by 30%. |
| Databáze: | OpenAIRE |
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