Nitroprusside and nitroglycerine in patients with posttraumatic pulmonary failure

Area of Science:

• Cardiovascular Physiology
• Respiratory Medicine
• Critical Care

Background:

• Post-traumatic pulmonary dysfunction often involves elevated pulmonary artery pressure.
• The reversibility and impact of pulmonary artery pressure reduction on gas exchange are not fully understood.

Purpose of the Study:

• To investigate the reversibility of elevated pulmonary artery pressure in patients with post-traumatic pulmonary dysfunction.
• To determine the effects of reducing pulmonary artery pressure on gas exchange.

Main Methods:

• Administration of vasodilators (nitroprusside and nitroglycerine) to 11 patients.
• Monitoring of pulmonary hemodynamics and gas exchange parameters.
• Assessment of changes in pulmonary artery pressure, pulmonary vascular resistance, cardiac output, and pulmonary shunt.

Main Results:

• Mean pulmonary artery pressure and pulmonary vascular resistance significantly decreased.
• Pulmonary shunt fraction increased, indicating improved blood flow distribution.
• Cardiac output remained unchanged during vasodilator administration.

Conclusions:

• The increase in pulmonary artery pressure in post-traumatic pulmonary dysfunction is partially reversible.
• Reversible restriction of blood flow past unventilated alveoli contributes to elevated pulmonary artery pressure.
• Hypoxic vasoconstriction is a likely major factor driving pulmonary artery pressure elevation in this patient group.