Interactions between respiration and systemic hemodynamics. Part II: practical implications in critical care
François Feihl1, Alain F Broccard
1Division of Clinical Pathophysiology, University Hospital (CHUV) and Lausanne University (UNIL), 1011, Lausanne, Switzerland. Francois.Feihl@chuv.ch
Intensive Care Medicine
|October 1, 2008
Summary
This review applies cardiorespiratory interaction concepts to clinical practice, explaining Kussmaul's sign and pulsus paradoxus. It explores using respiratory blood pressure variations and ultrasonography to assess volume status and positive pressure breathing's effects.
Area of Science:
- Cardiovascular Physiology
- Respiratory Physiology
- Critical Care Medicine
Background:
- Part I established foundational concepts of cardiorespiratory interactions.
- Understanding these interactions is crucial for clinical decision-making.
Purpose of the Study:
- To practically apply theoretical cardiorespiratory concepts.
- To elucidate mechanisms of Kussmaul's sign and pulsus paradoxus.
- To review methods for assessing volume status using respiratory variations and ultrasonography.
Main Methods:
- Literature review on respiratory variations in blood pressure for volume status assessment.
- Ultrasonographic investigation of great vein geometry fluctuations with respiration.
- Guytonian analysis of positive end-expiratory pressure (PEEP) effects on cardiac output.
Main Results:
- Mechanisms of Kussmaul's sign and pulsus paradoxus are described.
- Respiratory variations in blood pressure and great vein ultrasonography are effective for volume status evaluation.
- Positive pressure breathing's impact on cardiac output and potential for acute cor pulmonale are discussed.
Conclusions:
- The review provides practical applications of cardiorespiratory physiology in clinical settings.
- Understanding these principles aids in managing mechanical ventilation and weaning.
- Ultrasonography offers a non-invasive method for assessing fluid status.
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