The prognostic value of on-arrival arterial blood gas parameters in out-of-hospital cardiac arrest: pH versus pCO₂ for predicting ROSC
DOI:
https://doi.org/10.55629/pakjpathol.v37i2.979Abstract
Objective: Predicting ROSC in OHCA patients undergoing CPR, through on-arrival blood gas components, can help guide intensive clinical decision-making in already overburdened and understaffed emergency departments of low and middle-income countries like Pakistan.
Material and Methods: This prospective observational study was conducted at an urban teaching hospital facility for a period of 3 years and included 156 consecutively selected non-trauma OHCA patients undergoing CPR. Blood gas analysis was done on arrival at the emergency department. Baseline values, arterial pH, and pCO₂ levels were compared between the two groups (ROSC-achieved vs ROSC-not-achieved). Multiple logistic regression analysis identified independent ROSC predictors, and the ROC study compared the discriminative capacity of pH and pCO₂.
Results: The ROSC-achieved group exhibited significantly higher arterial pH than the other group (mean difference = 0.12, 95% CI: 0.06-0.18, p < 0.001). No significant difference in mean pCO₂ was found between the groups (p = 0.29). In the multiple logistic regression analysis, greater pH independently predicted ROSC (OR = 71.07, 95% CI: 4.11–1227.04; p = 0.003) while pCO₂ was not independently associated (OR = 1.02, 95% CI: 0.98-1.04, p = 0.29). The ROC analysis showed that pH has a higher discriminative capacity (AUC = 0.68) than pCO₂ (AUC =0.44).
Conclusion: The study found that arterial pH in the on-arrival blood gas sample can independently predict ROSC in OHCA patients undergoing CPR. Keywords: ABGs (arterial blood gases), OHCA (out-of-hospital cardiac arrest), pCO2(Partial pressure of carbon dioxide), ROSC (return of spontaneous circulation)
Keywords: OHCA, CPR, Blood gas analysis, ROSC
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