Reference Ranges of Glycemic Variability in Infants after Surgery—A Prospective Cohort Study

We aimed to define reference ranges of glycemic variability indices derived from continuous glucose monitoring data for non-diabetic infants during post-operative intensive care treatment after cardiac surgery procedures. We performed a prospective cohort intervention study in a pediatric intensive care unit (PICU). Non-diabetic infants aged 0–12 months after corrective cardiovascular surgery procedures were fitted upon arrival to the PICU with a continuous glucose monitoring system (iPro2, Medtronic, Minneapolis, MN, USA). Thirteen glycemic variability indices were calculated for each patient. Complete recordings of 65 patients were collected on the first postoperative day. During the first three postsurgical days 5%, 24% and 43% of patients experienced at least one hypoglycemia episode, and 40%, 10% and 15%—hyperglycemia episode, respectively, in each day. Due to significant differences between the first postoperative day (mean glycemia 130 ± 31 mg/dL) and the second and third day (105 ± 18 mg/dL, 101 ± 22.2 mg/dL; p < 0.0001), we proposed two separate reference ranges—for the acute and steady state patients. Thus, for individual glucose measurements, we proposed a reference range between 85 and 229 mg/dL and 69 and 149 mg/dL. For the mean daily glucose level, ranges between 122 and 137 mg/dL and 95 and 110 mg/dL were proposed. In conclusion, rt-CGM revealed a very high likelihood of hyperglycemia in the first postsurgical day. The widespread use of CGM systems in a pediatric ICU setting should be considered as a safeguard against dysglycemic episodes; however, reference ranges for those patients should be different to those used in diabetes care.