Abstract
Abstract
Background:
Acid–base disorders are frequently encountered in the emergency department and critical care unit and require prompt assessment for timely management. Arterial blood gas analysis remains the gold standard for evaluating acid–base status; however, it is invasive, painful, time-consuming, and costly. End-tidal carbon dioxide (ETCO
2
) monitoring using capnography is a noninvasive technique that reflects ventilation and metabolic status and may serve as a surrogate marker for certain arterial blood gas parameters.
Aim:
To determine the relationship between ETCO
2
and arterial blood gas bicarbonate (HCO
3
−
) levels in patients presenting with acid–base disorders.
Study Design and Setting:
This prospective, observational, and analytical study was conducted in the emergency department and critical care unit of a tertiary care teaching hospital.
Subjects and Methods:
A total of 100 adult patients aged 18 years and above presenting with acid–base disorders were included. ETCO
2
values were recorded using quantitative waveform capnography and arterial blood gas analysis was performed simultaneously to measure pH, PaCO
2
, PaO
2
, and HCO
3
−
levels. Correlation between ETCO
2
and arterial blood gas parameters was analyzed using Pearson correlation coefficient.
Results:
The mean age of the study population was 59.22 ± 9.30 years, with a near-equal gender distribution. ETCO
2
showed a statistically significant positive correlation with arterial bicarbonate and PaCO
2
levels, and a significant negative correlation with pH. These findings indicate that lower ETCO
2
values were associated with more severe metabolic acidosis.
Conclusion:
ETCO
2
monitoring demonstrates a significant correlation with arterial bicarbonate and PaCO
2
levels in patients with acid–base disorders. While ETCO
2
cannot replace arterial blood gas analysis, it may serve as a rapid, noninvasive adjunct for the early assessment of metabolic derangements in emergency settings.