Acute Respiratory Distress Syndrome and Fluid Management: Finding the Perfect Balance

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Summary of “Acute Respiratory Distress Syndrome and Fluid Management: Finding the Perfect Balance” (J. Clin. Med. 2025, 14, 2067)

Abstract

Acute Respiratory Distress Syndrome (ARDS) is characterized by alveolar epithelial injury leading to capillary leak and alveolar flooding. While fluid therapy is often essential in early resuscitation, excessive fluid administration may exacerbate pulmonary edema, impair gas exchange, and increase ventilator dependence. This review discusses the pathophysiological interplay between ARDS and fluid balance, reviews the evidence surrounding liberal vs. conservative fluid strategies, and suggests practical guidance for optimizing fluid therapy throughout the phases of ARDS.

Key Points

  1. Pathophysiology of ARDS and Fluid Leakage ARDS involves loss of alveolar-capillary integrity, causing leakage of protein-rich fluid into the alveolar space, impairing oxygenation and compliance, and making fluid overload a key modifiable factor.

  2. Initial Resuscitation and Hemodynamic Stabilization During early shock or sepsis-induced ARDS, fluid resuscitation is often necessary to restore perfusion. However, hemodynamic monitoring should be tightly integrated to prevent unnecessary fluid accumulation.

  3. Positive Pressure Ventilation and Cardiac Output Mechanical ventilation increases intrathoracic pressure, reducing venous return and cardiac output. This exacerbates the need for careful fluid titration to maintain organ perfusion without worsening lung injury.

  4. Evidence for Conservative Fluid Strategies Clinical trials, notably the FACTT trial, demonstrate that a conservative fluid strategy after initial stabilization reduces ventilator days and ICU stay without increasing organ dysfunction or mortality.

  5. Individualized, Phase-Based Approach to Fluid Management The review supports a “four phases” approach: rescue, optimization, stabilization, and de-escalation, with fluid administration guided by dynamic assessments and evolving clinical status.

  6. Assessment of Fluid Responsiveness Techniques such as passive leg raising, stroke volume variation, and echocardiography are emphasized over static parameters (like CVP) to assess fluid responsiveness and avoid overload.

  7. Impact of Fluid Balance on Lung Mechanics Excess fluid impairs lung compliance, increases driving pressure, and worsens outcomes. A net negative fluid balance is often associated with better ventilatory and survival metrics in ARDS patients.

  8. Integration with Other ARDS Therapies The fluid strategy should be harmonized with other ARDS interventions like low tidal volume ventilation, prone positioning, and neuromuscular blockade to support oxygenation while minimizing lung injury.

  9. Special Considerations in COVID-19-Related ARDS COVID-19 ARDS may present with different vascular phenotypes (e.g., vasoplegia, thrombosis), requiring tailored fluid approaches that balance perfusion goals with lung protection.

  10. Call for Personalized Protocols Given patient variability, the review underscores the need for fluid strategies tailored to underlying etiology, hemodynamics, and ARDS phase, rather than rigid protocols or one-size-fits-all approaches.

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Description of heart–lung interaction. (A): During spontaneous breathing, especially with excessive inspiratory effort, negative Ppl (–) and increase transvascular filtration pressure, leading to edema formation (blue arrow). At the cardiac level, negative intrathoracic pressure enhances venous return (VR +++), overcoming the increased LV afterload and in turn increasing CO. (B): During mechanical ventilation, the increase in Ppl (+) and Palv (++), leads to a decrease in pulmonary edema formation (double-sided blue arrow). At the cardiac level, increased intrathoracic pressures reduce VR and increase RV afterload (+++ PVR). Although partially compensated by a decrease in LV afterload and by a potential increase in LV preload, this leads to an overall decrease in CO. Ppl: pleural pressure; Hp: hydrostatic capillary pressure; LV: left ventricle; RV: right ventricle; CO: cardiac output.

Conclusion

Managing fluid balance in ARDS is a dynamic process that evolves with disease progression. While fluids are life-saving early in shock, conservative or de-escalation strategies after stabilization improve outcomes by minimizing pulmonary edema and ventilator burden. A phase-based, physiology-guided approach—integrated with mechanical ventilation strategies—offers the best chance of optimizing recovery.

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Pathophysiology of ARDS and consequences of its therapeutic management. The alveolar damage, the increased membrane permeability and the deteriorating gas exchange and respiratory mechanics happening during ARDS often require mechanical ventilation and aggressive fluid therapy. The interplay between them leads to consequences on the lungs, heart (and circulation), and distal organs such as the kidneys. ↑↑: increase; ↓↓ decrease.

Watch the following video on “Fluid Management in Acute Respiratory Distress Syndrome by S. Valentine | OPENPediatrics” by OPENPediatrics

© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

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