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Background:
Pediatric craniofacial surgery can be associated with significant blood loss. Intraoperative assessment of blood loss is often subjective and inaccurate. Metabolic acidosis, as measured by base deficit, correlates with the volume of intraoperative blood transfusion and lactic acidosis has been shown to be a more specific measure of end-organ perfusion in the trauma literature. The purpose of the current study was to identify if intraoperative lactate correlates with calculated blood loss (CBL) and validate if lactate can provide real-time measurement of intraoperative blood loss during pediatric craniofacial surgery.
Methods:
Using a prospective IRB approved database, we examined the intra- and post-operative records of 40 consecutive patients undergoing open craniofacial surgery at a children's hospital in a 12 month time period. Patients who did not have intraoperative lactate measurements were excluded (n=4). Subcranial procedures (e.g., Le Fort III osteotomies) were excluded (n=2). Intraoperative parameters from 34 patients included operative time, blood pressure, heart rate, urine output, volume of transfused packed red cells, base deficit, and lactate. Mean intraoperative lactate was correlated to the CBL, urine output (cc/kg/hr), and length of operation for each patient. Abnormal lactates were correlated to the mean heart rate and blood pressure during the preceding one hour. Pearson product-moment correlation coefficients were calculated to determine relationships between variables.
Results:
Six of 34 patients had at least one intraoperative lactate that was elevated. There was no correlation between mean intraoperative lactate and CBL for each patient (r=-0.102). Likewise, no correlation was identified between mean intraoperative lactate and urine output (r=0.147) or operative time (r=0.037). For each individual elevated lactate, there was no correlation between either mean heart rate (r=-0.033) or mean blood pressure one hour prior (r=-0.185) to that measured value.
Conclusions:
In our sample of pediatric patients undergoing cranial vault surgery, there was no correlation between lactic acid measurements and calculated blood loss. Furthermore, our analysis failed to identify an independent correlation between lactate and several common intraoperative parameters of perfusion. Further study is warranted to determine the efficacy of using intraoperative lactate as a guide for resuscitation management during pediatric craniofacial surgery.