Introduction A single centre has reported that implementation
of an intensive insulin protocol, aiming for tight glycaemic control
(blood glucose 4.4 to 6.1 mmol/l), resulted in significant
reduction in mortality in longer stay medical and surgical
critically ill patients. Our aim was to determine the degree to
which tight glycaemic control can be maintained using an
intensive insulin therapy protocol with computerized decision
support and to identify factors that may be associated with the
degree of control.
Methods At a general adult 22-bed intensive care unit, we
implemented an intensive insulin therapy protocol in
mechanically ventilated patients, aiming for a target glucose
range of 4.4 to 6.1 mmol/l. The protocol was integrated into the
computerized information management system by way of a
decision support program. The time spent in each predefined
blood glucose band was estimated, assuming a linear trend
between measurements.
Results Fifty consecutive patients were investigated, involving
analysis of 7,209 blood glucose samples, over 9,214 hours. The
target tight glycaemic control band (4.4 to 6.1 mmol/l) was
achieved for a median of 23.1% of the time that patients were
receiving intensive insulin therapy. Nearly half of the time
(median 48.5%), blood glucose was within the band 6.2 to 7.99
mmol/l. Univariate analysis revealed that body mass index (BMI),
Acute Physiology and Chronic Health Evaluation (APACHE) II
score and previous diabetes each explained approximately 10%
of the variability in tight glycaemic control. BMI and APACHE II
score explained most (27%) of the variability in tight glycaemic
control in the multivariate analysis, after adjusting for age and
previous diabetes.
Conclusion Use of the computerized decision supported
intensive insulin therapy protocol did result in achievement of
tight glycaemic control for a substantial percentage of each
patient's stay, although it did deliver 'normoglycaemia' (4.4 to
about 8 mmol/l) for nearly 75% of the time. Tight glycaemic
control was difficult to achieve in critically ill patients using this
protocol. More sophisticated methods such as continuous
blood glucose monitoring with automated insulin and glucose
infusion adjustment may be a more effective way to achieve tight
glycaemic control. Glycaemia in patients with high BMI and
APACHE II scores may be more difficult to control using
intensive insulin therapy protocols. Trial registration number 05/
Q0505/1.