Research

Tight glycaemic control: a prospective observational study of a computerised decision-supported intensive insulin therapy protocol

Rob Shulman¹ , Simon J Finney² , Caoimhe O'Sullivan³ , Paul A Glynne⁴ and Russell Greene⁵

¹Pharmacy Department, University College London Hospitals NHS Trust, 235 Euston Road, London, NW1 2BU, UK

²Adult Intensive Care Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK

³Medical Statistics Group, Joint University College London Hospitals/University College London Biomedical Research Unit, 149 Tottenham Court Road, London, W1P 9LL, UK

⁴Critical Care Department, University College London Hospitals NHS Trust, 235 Euston Road, London, NW1 2BU, UK

⁵Pharmacy Department, School of Health and Biomedical Sciences, Kings College London, 150 Stamford Street, London, SR1 9NH, UK

author email corresponding author email

Critical Care 2007, 11:R75doi:10.1186/cc5964

Published:	10 July 2007

See related commentary by Chase and Shaw, http://ccforum.com/content/11/4/160 and related letter by de Graaf et al., http://ccforum.com/content/11/5/421 and Volgeliang et al., http://ccforum.com/content/11/6/423

Abstract

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.