Comparison of two experimental ARDS models in pigs using electrical impedance tomography

Area of Science:

• Medical science
• Physiology
• Medical imaging

Background:

• Animal models are crucial for medical advancements.
• The lavage model is common for studying acute respiratory distress syndrome (ARDS) with electrical impedance tomography (EIT).
• The lavage model may systematically impact EIT parameters, necessitating alternative models like lipopolysaccharide (LPS)-induced ARDS.

Purpose of the Study:

• To compare EIT measurements in lavage-induced versus LPS-induced ARDS models.
• To determine if ARDS pathophysiology influences EIT-derived indices.
• To assess the consistency of global inhomogeneity (GI) and regional ventilation delay (RVD) indices between models.

Main Methods:

• Nineteen pigs were divided into control, lavage, and LPS groups.
• ARDS was induced, followed by hourly assessments over eight hours.
• Respiratory mechanics, hemodynamics, gas exchange, and EIT recordings were analyzed.

Main Results:

• EIT measurements were reliable in both ARDS models.
• Initially, the lavage group showed higher GI and RVD indices than the control and LPS groups.
• These differences diminished over time, and LPS-induced ARDS maintained more stable clinical lung injury parameters.

Conclusions:

• The two ARDS models exert different influences on GI and RVD indices.
• Underlying pathophysiology significantly affects EIT parameters.
• Findings suggest limitations in translating EIT-guided ARDS therapy from animal models to human patients.