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Is there more to glycaemic control than meets the eye?
Critical Care volume 11, Article number: 160 (2007)
Tight glycaemic control has emerged as a major focus in critical care. However, the struggle to repeat, improve and standardize the results of the initial landmark studies is ongoing. The prospective computerized glycaemic control study by Shulman et al. highlights two emerging and often overlooked aspects of intensive insulin therapy protocols beyond simple glycaemic performance. First, the clinical ergonomics and ability to integrate into the critical care unit workflow must be considered as they may impact results and definitely affect uptake. Second, the real lessons of any protocol's performance are likely to be best realized by comparison with other results, a task that is very difficult without a consensus method of reporting that allows such comparisons across studies. Embracing these issues will take the field closer to accepted, repeatable approaches to tight glycaemic control.
That tight glycaemic control in critical care saves lives is increasingly less questioned. In contrast, the how and for whom remains quite elusive. In this journal, Shulman et al.  report the results of another prospective glycaemic control study utilizing a computerized protocol to implement a relatively complex protocol.
Tight control has been of great interest since the landmark studies of Van den Berghe et al. [2, 3] and Krinsley . At least two to three further, large, randomized trials have been started, including the ongoing Normoglycemia in Intensive Care Evaluation (NICE)-Survival Using Glucose Algorithm Regulation (SUGAR) studies , and the discontinued Efficacy of Volume Substitution and Insulin Therapy in Severe Sepsis (VISEP) study . Finally, several prospective studies, primarily focused on developing new protocols, have been published, to the extent that reviews have recently appeared [7–9].
Two common themes emerge that are also evident in this study. The first concerns the impact of clinical burden on the results obtained. The second is one of performance. What defines good performance, and what level is required to achieve the mortality and economic [10, 11] outcomes of the landmark studies?
The clinical burden of intensive insulin therapy (IIT) has not gone unnoticed [12, 13]. Shulman and colleagues, have uniquely addressed this issue directly by tracking compliance in the timing of glucose measurements and thus perhaps compliance and performance in control. Only 53% (interquartile range: 41 to 67%) of glucose measurements were performed in the specified one to two hour timeframe, including a 50% (30 to 60 minutes) buffer. This result is unique in the field and clearly shows for the first time the difficulty of integrating any protocol into the typically hectic intensive care unit (ICU) environment.
In contrast, Van den Berghe et al. [2, 3] utilized additional staff to reduce burden and avoid contamination across their randomized trial. The higher average glycaemic control obtained by Krinsley  without such extra staffing thus indicates the (potential) impact of clinical burden on performance. This paper thus clearly highlights the little addressed issue of human factors and the need to consider them explicitly in protocol design – perhaps including experts in the field – to obtain more consistent results. More succinctly, it may not be the protocol but the ability to implement it effectively that prevents success in some cases.
Regarding performance, patients in this study were in the target 4.4 to 6.1 mmol/L band, a median of 23.1% (15.4 to 29.1%) of the time, with a further 48.5% (36.9 to 60.8%) in the 6.2 to 7.99 mmol/L band. The authors conclude that the protocol "did not achieve tight glycaemic control for a substantial portion of each patient's stay". However, their results are similar in average value and tighter in distribution than the very successful results of Krinsley , based on values estimated from Figure 2 and Table 4 in Krinsley's original work  and the data presented by Shulman et al. They are also similar to other studies [14–16].
This contradiction illustrates the almost complete inability to assess or compare performance consistently across studies. A review of 24 studies  shows that five use percentage time in a single band, while most others use a mean value and standard deviation. Target range and measurement frequency also varied considerably. Combined with differences in cohort and critical illness, it is very difficult to take significant lessons away from many of these studies. This is not a fault of the study authors or implementation, but a lack of a consensus means of reporting.
Shulman et al., provide significant insight into their results compared to many others, reporting percentage time in bands on a per patient basis as well as indicating the variability across the cohort via the box and whiskers plot of Figure 2. From this data and Table 4 it is possible to determine both median and variability on a per patient basis – the same basis on which tight control has a clinical impact. It is also something not reported in most similar studies, making this study unique for its transparency. Variability is particularly important as a recent study of over 7,000 patients showed that the glycaemic variability is an independent predictor of mortality , and thus a potentially critical performance measure.
In contrast, almost all studies report glycaemic control in terms of overall results, rather than per patient. Thus, one could (in extreme) report relatively wide variability for a protocol, when in fact each patient was tightly controlled within that range – or vice versa. Shulman et al.'s complete and transparent per patient reporting is a stronger template on which to make comparisons and derive lessons learned.
Thus, a second clear outcome highlighted by this study is the need for a consensus statement with regard to reporting glycaemic control performance. A better understanding would result from specifying a minimum standard that included per patient and overall results for a series of accepted glycaemic ranges and thus variability. This call is not necessarily new , but perhaps bears repeating.
More succinctly, a standard method of reporting results would enable easier comparison across studies and cohorts, with an ultimate goal of enabling better understanding of what performance metrics (time in band, variability, etc) are important. Coupled with improved ergonomics and integration into typical ICU environments, the potential to create consistently repeatable results will increase, potentially substantially. And thus, we might well be able to begin answering the difficult questions of how and for whom".
intensive care unit
intensive insulin therapy
Normoglycemia in Intensive Care Evaluation-Survival Using Glucose Algorithm Regulation [studies]
Efficacy of Volume Substitution and Insulin Therapy in Severe Sepsis [study].
Shulman R, Finney SJ, Greene R, Glynne PA, O'Sullivan C: Tight glycaemic control: a prospective observational study of a computerised decision-supported intensive insulin therapy protocol. Crit Care 2007, 11: R75. 10.1186/cc5964
Van den Berghe G, Wouters P, Weekers F, Verwaest C, Bruyninckx F, Schetz M, Vlasselaers D, Ferdinande P, Lauwers P, Bouillon R: Intensive insulin therapy in critically ill patients. N Engl J Med 2001, 345: 1359-1367. 10.1056/NEJMoa011300
Van den Berghe G, Wilmer A, Hermans G, Meersseman W, Wouters PJ, Milants I, Van Wijngaerden E, Bobbaers H, Bouillon R: Intensive insulin therapy in the medical ICU. N Engl J Med 2006, 354: 449-461. 10.1056/NEJMoa052521
Krinsley JS: Effect of an intensive glucose management protocol on the mortality of critically ill adult patients. Mayo Clin Proc 2004, 79: 992-1000.
McMullin J, Brozek J, McDonald E, Clarke F, Jaeschke R, Heels-Ansdell D, Leppert R, Foss A, Cook D: Lowering of glucose in critical care: a randomized pilot trial. J Crit Care 2007, 22: 112-118. 10.1016/j.jcrc.2006.08.002
Brunkhorst F, Kuhnt E, Engel C, MeierHellmann A, Ragaller M, Quintel M, Weiler N, Gründling M, Oppert M, Deufel T, et al.: Intensive insulin therapy in patient with severe sepsis and septic shock is associated with an increased rate of hypoglycemia – results from a randomized multicenter study (VISEP). Infection 2005, (Suppl 1):19.
Meijering S, Corstjens AM, Tulleken JE, Meertens JH, Zijlstra JG, Ligtenberg JJ: Towards a feasible algorithm for tight glycaemic control in critically ill patients: a systematic review of the literature. Crit Care 2006, 10: R19. 10.1186/cc3981
Wilson M, Weinreb J, Hoo GW: Intensive insulin therapy in critical care: a review of 12 protocols. Diabetes Care 2007, 30: 1005-1011. 10.2337/dc06-1964
Schultz MJ, Royakkers AA, Levi M, Moeniralam HS, Spronk PE: Intensive insulin therapy in intensive care: an example of the struggle to implement evidence-based medicine. 2006, 3: e456.
Van den Berghe G, Wouters PJ, Kesteloot K, Hilleman DE: Analysis of healthcare resource utilization with intensive insulin therapy in critically ill patients. Crit Care Med 2006, 34: 612-616.
Krinsley JS, Jones RL: Cost analysis of intensive glycemic control in critically ill adult patients. Chest 2006, 129: 644-650. 10.1378/chest.129.3.644
Aragon D: Evaluation of nursing work effort and perceptions about blood glucose testing in tight glycemic control. Am J Crit Care 2006, 15: 370-377.
Mackenzie I, Ingle S, Zaidi S, Buczaski S: Tight glycaemic control: a survey of intensive care practice in large English hospitals. Intensive Care Med 2005, 31: 1136. 10.1007/s00134-005-2677-2
Goldberg PA, Sakharova OV, Barrett PW, Falko LN, Roussel MG, Bak L, Blake-Holmes D, Marieb NJ, Inzucchi SE: Improving glycemic control in the cardiothoracic intensive care unit: clinical experience in two hospital settings. J Cardiothorac Vasc Anesth 2004, 18: 690-697. 10.1053/j.jvca.2004.08.003
Goldberg PA, Siegel MD, Sherwin RS, Halickman JI, Lee M, Bailey VA, Lee SL, Dziura JD, Inzucchi SE: Implementation of a safe and effective insulin infusion protocol in a medical intensive care unit. Diabetes Care 2004, 27: 461-467. 10.2337/diacare.27.2.461
Zimmerman CR, Mlynarek ME, Jordan JA, Rajda CA, Horst HM: An insulin infusion protocol in critically ill cardiothoracic surgery patients. Ann Pharmacother 2004, 38: 1123-1129. 10.1345/aph.1E018
Egi M, Bellomo R, Stachowski E, French CJ, Hart G: Variability of blood glucose concentration and short-term mortality in critically ill patients. Anesthesiology 2006, 105: 244-252. 10.1097/00000542-200608000-00006
Gale SC, Gracias VH: Glycemic control needs a standard reference point. Crit Care Med 2006, 34: 1856-1857. 10.1097/01.CCM.0000220201.72591.43
The authors have also published and done research extensively in the field of IIT protocol design.
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Chase, J.G., Shaw, G.M. Is there more to glycaemic control than meets the eye?. Crit Care 11, 160 (2007). https://doi.org/10.1186/cc6099
- Glycaemic Control
- Glucose Measurement
- Intensive Insulin Therapy
- Percentage Time
- Landmark Study