Comparative performance of capillary versus arterial blood gas measurements in neonates: a systematic review and meta-analysis
S. Pooja, Kalesh M. Karun, Roseline K. Madathil, Manu Rajan Idicula, M. S. Deepthy, Flemin Felix, Sheethal Joseph, K. K. DiwakarAbstract
Background:
Arterial blood gas analysis is the gold standard for evaluating acid–base status and ventilation in neonates, but it is invasive and carries procedural risks. Capillary blood gas sampling is less invasive and more feasible, but its reliability compared with arterial blood gas remains debated.
Objective:
The aim of this study was to systematically evaluate and compare blood gas parameters (PCO 2 , PO 2 , pH) between arterial and capillary samples in neonates.
Methods:
Following PRISMA guidelines, a protocol registered in PROSPERO (CRD42022335502) was implemented. PubMed, Scopus, and ScienceDirect were searched for observational studies reporting paired arterial and capillary blood gas values in neonates. Two reviewers independently screened studies, extracted data, and assessed quality using the Newcastle–Ottawa Scale and JBI tools. Pooled mean differences were estimated using random-effects models; heterogeneity was assessed by I 2 statistics. Subgroup and sensitivity analyses explored the influence of capillary site arterialization.
Results:
Thirteen studies were included. For PCO 2 , the pooled mean difference was −1.32 mmHg (95% confidence interval [CI]: −3.67 to 1.04), suggesting no significant difference, although heterogeneity was high (I 2 = 97%). For PO 2 , capillary samples consistently underestimated arterial values, with a pooled mean difference of 14.88 mmHg (95% CI: 10.64–19.12; I 2 = 95%). For pH, the pooled mean difference was negligible (0.00; 95% CI: −0.02 to 0.02; I 2 = 93%), indicating minimal average difference between measurements. Sensitivity and subgroup analyses confirmed robustness; arterialization had minimal effect.
Conclusion:
Capillary blood gas analysis showed comparable average values for pH and PCO 2 ; however, given the substantial heterogeneity among studies, these findings should be interpreted cautiously.