P pulmonale in status asthmaticus.

Area of Science:

• Cardiology
• Pulmonology
• Critical Care Medicine

Background:

• Acute, severe asthma attacks present significant physiological challenges.
• Electrocardiographic (ECG) findings in asthma patients require further investigation.

Purpose of the Study:

• To investigate the prevalence and underlying mechanisms of P pulmonale in patients experiencing acute, severe asthma.
• To explore the relationship between arterial blood gas levels and ECG abnormalities.
• To determine the duration of P pulmonale persistence and its potential causes.

Main Methods:

• Studied 129 patients during acute, severe asthmatic attacks.
• Utilized electrocardiograms (ECGs) to identify P pulmonale.
• Analyzed arterial carbon dioxide tension (PaCO2) and arterial pH.
• Performed cardiac catheterization in a subset of patients with P pulmonale and respiratory acidosis.

Main Results:

• P pulmonale was observed in 49% of patients with PaCO2 ≥ 45 mm Hg and pH ≤ 7.37, versus 2.5% in those with PaCO2 ≤ 44 mm Hg and pH ≥ 7.38 (p < 0.001).
• P wave and QRS axes were significantly shifted in the presence of P pulmonale and normalized upon its disappearance.
• ECG P pulmonale persisted for 12–60 hours after correction of hypoxemia, hypercapnia, and acidosis.
• Cardiac catheterization revealed normal pulmonary artery pressures (PAPs) but increased peak inspiratory pulmonary artery transmural pressures (PATPs) in patients with P pulmonale and respiratory acidosis.

Conclusions:

• Reversible P pulmonale in status asthmaticus is associated with severe hypercapnia and acidosis.
• The findings support the hypothesis that negative tidal pleural pressures and increased right heart transmural pressures contribute to P pulmonale.
• P pulmonale may indicate right heart strain due to altered intrathoracic pressures during severe asthma exacerbations.