How well are we collecting umbilical cord lactate and gas samples?

The aim of this study is to measure staff compliance with the local umbilical cord lactate (UCL) sampling guideline and investigate the quality of paired UCG samples at a tertiary maternity unit.

We performed a retrospective consecutive sampling of 100 babies delivered via emergency caesarean section and 50 babies with each of all other guideline-based indications for UCL sampling born on and before 31 December 2021. Data were extracted from physical and electronic records. Compliance with guideline-based indications for UCL at birth was measured. The proportion of valid UCG samples was calculated. Samples were considered invalid under the following cases: (i) inadvertently collecting from the same vessel, (ii) switching arterial and venous samples, (iii) collecting from only one vessel or (iv) committing errors during sample collection and handling.

Of the samples collected at birth from 321 babies, 280 (87%) had UCL. Small for gestational age and concerns about fetal well-being in labour were indications associated with poorer compliance, 66% and 78%, respectively. About 99 (44%) babies of 226 babies with UCG performed had valid UCG samples. The most common reasons for invalid samples were collection and handling errors (22%) and inadvertent collection from the same vessel (15%).

Generally, compliance with the guidelines is good. However, invalid UCG samples were more frequent than expected.