Histopathologic pulmonary changes from mechanical ventilation at high peak airway pressures

Area of Science:

• Pulmonary Medicine
• Critical Care Medicine
• Veterinary Pathology

Background:

• Mechanical ventilation (MV) with high airway pressures is used to support patients with respiratory failure.
• The potential for MV to induce lung injury, particularly in vulnerable populations, requires thorough investigation.

Purpose of the Study:

• To investigate the histopathologic pulmonary changes induced by high peak airway pressure and large tidal volume mechanical ventilation in healthy baby pigs.
• To compare these induced changes to the stages of adult respiratory distress syndrome (ARDS).

Main Methods:

• Healthy baby pigs were subjected to aggressive MV with high peak inspiratory pressure (PIP) and large tidal volumes.
• Control animals received MV with lower PIP.
• Histopathologic examination of lung tissue was performed.

Main Results:

• High-pressure MV induced alveolar hemorrhage, neutrophil infiltration, type II pneumocyte proliferation, interstitial congestion, and hyaline membrane formation.
• These lesions were comparable to early-stage ARDS.
• Prolonged ventilation resulted in organized alveolar exudate, mimicking late-stage ARDS.
• Control animals showed no significant histopathologic changes.

Conclusions:

• Aggressive mechanical ventilation with high peak inspiratory pressure can induce significant pulmonary histopathologic changes in piglets.
• These changes resemble both early and late stages of adult respiratory distress syndrome (ARDS).
• Careful ventilator management is crucial to mitigate ventilator-induced lung injury (VILI).