OBJECTIVETo analyze the variation of serum insulin levels in critically ill children and investigate the underlying mechanism and clinical significance to provide the basis for treatment.

METHODTotally 332 critically ill children admitted in pediatric intensive care unit (PICU) of Hunan Children's Hospital from Nov., 2011 to April, 2012 were studied. The high insulin group (n = 332) was defined as insulin levels within 24 h > 11.1 mU/L and was divided into 2 groups: mildly elevated group (n = 194): 11.10 - 33.30 mU/L, increased three times group (n = 138): > 33.3 mU/L. Insulin, C-peptide and blood glucose were measured within 24 hours after admission, on day 3 and 7. Other results of inflammatory markers, lactate, cardiac enzymes, amylase, pancreatic ultrasound, hepatic and renal function as well as indicators related to severity and prognosis were recorded after admission.

RESULTThe peak of insulin level was seen on day 1, then presented a downward trend and reached the normal level on day 7. The peaks of blood glucose and C-peptide level were seen on day 1 then declined, the levels on day 7 were still slightly higher than normal level. The insulin level on admission (41.47 ± 30.85) mU/L were positively correlated with lactic acid (2.29 ± 1.81) mmol/L and procalcitonin level (5.08 ± 6.70) ng/ml (r = 0.370, P = 0.000; r = 0.168, P = 0.002) (P < 0.01). The insulin level on admission in children with 1 organ failure (41.24 ± 22.60) mU/L or 2 or multiple organ failure (48.98 ± 22.17) mU/L was higher than that in children with non-organ failure (34.11 ± 29.84) mU/L (U = 1621.001, P = 0.000;U = 1300.000, P = 0.000) (P < 0.01). The insulin level on admission in death group (52.99 ± 32.34) mU/L was higher than that in survival group (32.85 ± 24.10) mU/L (U = 1585.000, P = 0.000) (P < 0.01). Ten cases in death group were complicated with pancreatic damage and the average insulin level on admission was (65.29 ± 50.53) mU/L.

CONCLUSIONThe high insulin level was correlated with the degree of inflammatory response, ischemia and hypoxia. The high insulin level in critically ill children was relevant to the pancreatic damage, the severity of the disease, organ dysfunction, and evaluation of prognosis.