[NO inhalation in heart surgery procedures: relevance for right heart function?]

Area of Science:

• Cardiology
• Pulmonary Medicine
• Critical Care Medicine

Background:

• The right ventricle is more susceptible to injury during cardiopulmonary bypass than the left ventricle.
• Impaired right ventricular function may benefit from afterload reduction.
• Inhaled nitric oxide (NO) can selectively reduce pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) without affecting systemic circulation.

Purpose of the Study:

• To investigate the effects of inhaled NO on PAP, PVR, and right heart parameters immediately after weaning from cardiopulmonary bypass.
• To explore the influence of age, preoperative heart function, and extracorporeal circulation duration on the response to NO inhalation.

Main Methods:

• A randomized controlled study included 20 patients with moderately increased PAP.
• Ten patients inhaled 30 ppm NO, while ten served as a control group.
• Measurements of PAP, PVR, right ventricular ejection fraction, systemic blood pressure, and oxygenation were taken at various time points post-bypass.

Main Results:

• Inhaled NO led to a significant decrease in PAP and PVR, but this did not improve right heart function.
• No significant difference in PAP or PVR reduction was observed between the NO and control groups.
• No adverse effects such as intoxication or impaired oxygenation were noted.

Conclusions:

• Inhaled NO did not provide immediate benefit to right heart function in patients with moderate pulmonary hypertension post-cardiopulmonary bypass.
• The observed reductions in PAP and PVR were not specific to NO inhalation, suggesting a need for further investigation.
• High concentrations of NO did not impair oxygenation, and a control group is recommended for future studies involving NO inhalation.