Metabolic changes during major craniofacial surgery

The purpose of this study was to document the degree and duration of perioperative metabolic disturbance during major craniofacial surgery in children.

The aim was to quantify the degree and duration of perioperative metabolic disturbance and to determine the relationship between the metabolic changes and the duration of surgery and total volume of blood and colloid given during surgery.

These patients have the potential for massive blood loss and significant metabolic acidosis. Routine perioperative monitoring includes the serial measurement of base deficit (BD) as a marker of metabolic disturbance.

All patients undergoing elective major craniofacial surgery were prospectively studied over a 10-month period. BD from arterial blood gas analysis was measured at standardized intervals during the perioperative period. The duration of surgery and total volume of blood and colloid given intraoperatively were used as covariates in a multiple regression analysis.

Maximum recorded BD ranged from -3 to -20 (median -9). Median time taken to return to normal was 9.25 h (range 0-18 h). Median duration of significant BD was 3.8 h (range 0-20 h).

Children undergoing major craniofacial surgery develop a varying degree of perioperative metabolic acidosis persisting for several hours. The maximum BD appears to be related to the amount of intraoperative blood loss and replacement rather than duration of surgery. As it is difficult to predict the extent and duration of metabolic acidosis for an individual patient, this study confirmed our current practice that all patients should be admitted to a neurosurgical high-dependency unit postoperatively for overnight monitoring.