Tight glycemic control did not significantly affect the number of days alive and free from mechanical ventilation among children cared for in intensive care units following cardiac surgery, according to a report published online Jan. 8 in the New England Journal of Medicine.
However, moderate hypoglycemia (defined as blood glucose levels of 36-45 mg/dL) developed in significantly more patients on tight glycemic control (12.5%) than in those on conventional glycemic control (3.1%), as did severe hypoglycemia (7.3% vs. 1.5%, respectively) in the cardiac surgery patients. All eight patients who developed seizures after severe hypoglycemic events were in the tight glycemic control group, reported Dr. Duncan Macrae of Royal Brompton and Harefield National Health Service Foundation Trust, London, and his associates.
Dr. Duncan Macrae
Reducing blood glucose to normal levels using insulin infusions during critical illness is known to reduce morbidity and mortality among adults in intensive care, but has not been well studied in children, the researchers noted.
In particular, data are lacking in regard to tight glycemic control (maintaining glucose levels in the range of 72-126 mg/dL) as compared to conventional glycemic control (initiating insulin if blood glucose exceeds 216 mg/dL and discontinuing it when the level drops below 180 mg/dL).
The CHiP (Control of Hyperglycemia in Paediatric Intensive Care) study was a multicenter, randomized trial that involved 1,369 patients ranging in age from 36 weeks of corrected gestational age to 16 years who were treated at 13 pediatric intensive care units in England. All the patients were critically ill following major surgery, injury, or other illness; all had an arterial catheter in place and were receiving mechanical ventilation and vasoactive drugs. None had diabetes or other inborn errors of metabolism.
A total of 60% of the patients were in the ICU following cardiac surgery.
The children were randomly assigned to receive either tight glycemic control (694 patients) or conventional glycemic control (675 patients) during their ICU stay.
The primary outcome measure was the number of days alive and free from mechanical ventilation at 1 month after randomization, which was not significantly different between the tight-control and the conventional-control groups (23.6 days vs. 23.3 days, respectively).
The findings are consistent with the results of the NICE-SUGAR study, "and should be considered as further evidence to support the use of conventional management of blood glucose levels in patients who have undergone cardiac surgery," the researchers noted.
Tight glycemic control was associated with a complex array of benefits and harms among critically ill children cared for in ICUs for reasons other than cardiac surgery. So the strategy must be carefully considered, with potential harms and benefits judiciously weighed, in this patient population, Dr. Macrae and his colleagues added.
Mortality was 11.1% among patients who had one or more hypoglycemic events, compared with only 4.4% among those who had no hypoglycemic events. And in the large subgroup of patients who had undergone cardiac surgery, 10.6% of those who had one or more hypoglycemic events died, compared with only 2.1% of those who had no hypoglycemic episodes, the researchers reported (N. Engl. J. Med. 2014;370:107-18 [doi: 10.1056/NEJMoa1302564]).
"In contrast, there was no excess mortality attributable to hypoglycemia in the subgroup that had not undergone cardiac surgery," the investigators said.
This subgroup that had not undergone cardiac surgery also was less likely to require renal replacement therapy, and had a shorter length of stay by 13.5 days if its members received tight rather than conventional glycemic control.
And the 1-year costs of care were lower by more than $13,000 per patient among children in the ICU for reasons other than cardiac surgery who received tight glycemic control, compared with those who received conventional glycemic control.
"However, this overall benefit must be balanced against the [increased] risk of hypoglycemia," the researchers noted.
This study was funded by the U.K. National Health Service. No commercial support was received. Dr. Macrae and his colleagues had no financial conflicts to disclose.