Introduction

Haemoglobin measurement is an essential parameter for quantifying anaemia and often used for guiding transfusion decisions. Conventional methods require blood sampling and are invasive. Results are intermittent, discontinuous and obtained after a reasonable acquisition time. Hemoglobinemia by pulsed co-oximetry is non-invasive, immediate and offers the advantage of continuous monitoring. The aim of this systematic review is to assess the diagnostic accuracy of pulsed co-oximetry compared with reference biological determinations in perioperative management.

Methods

The review was registered in PROSPERO and performed according to the PRISMA statement. Searches in Pubmed, Cochrane Library and Scopus databases were performed from January 2000 to February 2024 for studies comparing non-invasive haemoglobin measurement with invasive methods. The QUADAS-2 scale was used to assess the risk of bias. For data analysis, Review Manager 5.4.1 software was employed, using the inverse variance method and a random-effects model to calculate the mean difference (MD) and 95% confidence intervals. Sensitivity analysis were performed in order to assess the influence of site of blood sampling (arterial or venous), revision model reference of the Masimo finger sensor, the geographical location of the study centre, the risk of bias classification, the population type and the type of study.

Results

The meta-analysis included 36 studies involving 1888 patients. Meta-analysis revealed a mean difference between the non-invasive and invasive methods of 0.13 g.dL-1 (95% confidence interval [CI]: 0.10- 0.36) (P-value > 0.05). Sensitivity analyses showed no statistically significant difference between the two methods. There was a very good homogeneity among the studies (I² = 0%). Trending analysis was considered acceptable in a majority of the studies.

Conclusion

The results obtained support the reliability of pulsed co-oximetry. Considering the potential benefits of this parameter, it seems rational to integrate this technology perioperatively to guide standard clinical practices for optimizing the management of surgical patients.