1. Heart–Lungs interactions: the basics and clinical implications.
- Author
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Jozwiak, Mathieu and Teboul, Jean-Louis
- Subjects
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LUNG physiology , *ADULT respiratory distress syndrome treatment , *HEART physiology , *CARDIOPULMONARY system physiology , *LEFT heart ventricle , *DISEASE exacerbation , *PATIENTS , *PULMONARY circulation , *LEFT heart atrium , *MYOCARDIAL ischemia , *POSITIVE end-expiratory pressure , *RESPIRATION , *PULMONARY edema , *FLUID therapy , *HEMODYNAMICS , *HEART , *LUNGS , *HEART failure , *VASCULAR resistance , *ARTERIAL pressure , *INTRA-abdominal pressure , *RIGHT heart atrium , *RESPIRATORY measurements , *INSUFFLATION , *OBSTRUCTIVE lung diseases , *RIGHT heart ventricle , *STROKE volume (Cardiac output) , *VENTILATOR weaning , *MECHANICAL ventilators , *DISEASE risk factors - Abstract
Heart–lungs interactions are related to the interplay between the cardiovascular and the respiratory system. They result from the respiratory-induced changes in intrathoracic pressure, which are transmitted to the cardiac cavities and to the changes in alveolar pressure, which may impact the lung microvessels. In spontaneously breathing patients, consequences of heart–lungs interactions are during inspiration an increase in right ventricular preload and afterload, a decrease in left ventricular preload and an increase in left ventricular afterload. In mechanically ventilated patients, consequences of heart–lungs interactions are during mechanical insufflation a decrease in right ventricular preload, an increase in right ventricular afterload, an increase in left ventricular preload and a decrease in left ventricular afterload. Physiologically and during normal breathing, heart–lungs interactions do not lead to significant hemodynamic consequences. Nevertheless, in some clinical settings such as acute exacerbation of chronic obstructive pulmonary disease, acute left heart failure or acute respiratory distress syndrome, heart–lungs interactions may lead to significant hemodynamic consequences. These are linked to complex pathophysiological mechanisms, including a marked inspiratory negativity of intrathoracic pressure, a marked inspiratory increase in transpulmonary pressure and an increase in intra-abdominal pressure. The most recent application of heart–lungs interactions is the prediction of fluid responsiveness in mechanically ventilated patients. The first test to be developed using heart–lungs interactions was the respiratory variation of pulse pressure. Subsequently, many other dynamic fluid responsiveness tests using heart–lungs interactions have been developed, such as the respiratory variations of pulse contour-based stroke volume or the respiratory variations of the inferior or superior vena cava diameters. All these tests share the same limitations, the most frequent being low tidal volume ventilation, persistent spontaneous breathing activity and cardiac arrhythmia. Nevertheless, when their main limitations are properly addressed, all these tests can help intensivists in the decision-making process regarding fluid administration and fluid removal in critically ill patients. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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