The effect of time, temperature and storage device on umbilical cord blood gas and lactate measurement: a randomized controlled trial.

OBJECTIVE

Umbilical cord blood gas analysis has a significant and growing role in early neonatal assessment. Factors often delay analysis of cord blood allowing values to change. Consequently, this study evaluates the impact of time, temperature and method of storage on umbilical blood gas and lactate analyses.

METHODS

Umbilical cord segments from 80 singleton deliveries were randomized to: cords at room temperature (CR), cords stored on ice (CI), syringes at room temperature (SR) or syringes stored on ice (SI). Analysis occurred every 15 minutes for one-hour. Mixed model analysis of variance allowing for repeated measures was utilized.

RESULTS

Cord arterial pH deteriorated in CR, CI, and SI within 15 minutes (p ≤ 0.001), with SR stable until 60 minutes (p = 0.002). Arterial pCO(2) remained stable in SR and CI, increased in SI (p = 0.002; 45 minutes) and decreased in CR (p < 0.001; 45 minutes). Arterial base excess deteriorated in CR and SI (p ≤ 0.009; 15 minutes), SR (p < 0.001; 30 minutes), and CI (p < 0.001; 45 minutes). Arterial lactate levels increased within 15 minutes in all groups (p < 0.001).

CONCLUSIONS

Cord blood gas values change rapidly after delivery. Smallest changes were seen in SR group. Data suggest that analyses should be conducted as soon as possible after delivery.