Relation between partial arterial carbon dioxide pressure and pH value and optic nerve sheath diameter: a prospective...

Area of Science:

• Ophthalmology
• Pulmonology
• Critical Care Medicine

Background:

• Acute hypercarbic respiratory failure (AHRF) in COPD patients presents significant clinical challenges.
• Monitoring arterial blood gas (ABG) parameters like PaCO2 and pH is crucial for managing AHRF.
• Non-invasive ventilation (NIMV) is a common treatment modality for AHRF.

Purpose of the Study:

• To investigate the correlation between optic nerve sheath diameter (ONSD) and arterial blood gas (ABG) parameters (PaCO2, pH) before and after NIMV treatment.
• To assess if ONSD can serve as a surrogate marker for changes in PaCO2 and pH in COPD patients with AHRF.

Main Methods:

• Prospective, self-controlled, non-randomized trial involving 44 COPD patients with AHRF requiring NIMV.
• ONSD and ABG (PaCO2, pH) were measured before and after NIMV treatment.
• Demographic data, vital signs, and consciousness state were also recorded.

Main Results:

• A significant positive correlation was observed between mean ONSD and PaCO2 (p < 0.0001), with a high fit (0.72).
• A significant negative correlation was found between mean ONSD and pH (p < 0.0001), though with a lower fit (0.32).
• ONSD measurements demonstrated significant changes corresponding to acute alterations in PaCO2.

Conclusions:

• ONSD changes are highly correlated with acute changes in PaCO2 levels in COPD patients experiencing AHRF.
• ONSD may serve as a valuable, non-invasive indicator for monitoring hypercarbia in AHRF patients.
• Further research is warranted to validate ONSD as a routine monitoring tool in critical care settings.