Background & Objectives: Blood lactate levels are useful for assessing tissue hypoxia. Increased concentration of lactate after cardiovascular surgery in pediatric patients is a predictive value for postoperative morbidity and mortality1). The perfusion index (PI), meanwhile, is a value calculated as the ratio of the pulsatile and non-pulsatile components in the pulse oximetry waveform. Accordingly, PI has been shown to reflect changes in peripheral circulation perfusion and central hypovolemia2). We hypothesize that changes in PI values and lactate levels would be related in cardiovascular surgery.
Materials & Methods: This study was conducted with the approval of the Fukushima Medical University ethics committee. We retrospectively compared PI (Masimo Rainbow SETTM) and lactate levels obtained by arterial blood gas analysis using a blood gas analyzer (Siemens Rapid lab 1265) performed on pediatric patients undergoing cardiovascular surgery at our hospital between January 2014 and December 2015.
Results: Our study included 71 subjects (ages, 1.18 ± 2.01 [0.025–13.3] years; height, 65.7 ± 19.4 [44–155] cm; and weight, 7.03 ± 6.35 [2.27–49.3] kg; data are mean ± standard deviation [range]). Blood was sampled a total of 324 times. The correlation between PI values/PI values before the start of surgery (PIF) and lactate levels/lactate levels before the start of surgery (lacF) were examined in two groups: 1) PIF < 1.4 and 2) PIF ≥ 1.4. In the PIF < 1.4 group, the correlation efficient(R) between the two indices was -0.036(P=0.76). In the PIF ≥ 1.4 group, they were significantly, albeit weakly, correlated (R=-0.23, P=0.003).
Conclusion: In cases of pediatric cardiovascular surgery where the PI is high prior to the start of surgery, its value may be useful for predicting a rise in lactate levels.
1. Basaran M, Sever K, Kafali E, et al. Serum lactate level has prognostic significance after pediatric cardiac surgery. Journal of Cardiothoracic Vascular Anesthesia 2006; 20:43–7
2. Van Genderen ME, Bartels SA, Lima A, et al. Peripheral perfusion index as an early predictor for central hypovolemia in awake healthy volunteers. Anesthesia & Analgesia. 2013; 116:351–6
Disclosure of Interest: None declared