Introduction
Intensive insulin therapy (blood glucose < 6.1 mmol/l) may reduce mortality after cardiac surgery (by 42%) [1]. An effective regime would keep blood glucose < 6 mmol/l for 80% of the time; < 8 for 90% of the time and <12 for 99% of the time, and no hypos (< 3.0).
Method
Ninety elective heart surgery patients were recruited, and randomly allocated a 'Fixed' regimen (F) (Table 1) or a 'Variable' regimen (V) (Table 2) (n = 45). Blood sugars were recorded 1–2 hourly postoperatively for 48 hours. In each patient the mean and standard deviation were calculated. Episodes of hypoglycaemia (< 3 mmol/l), and mild (6.1–8.0), moderate (8.1–12) or severe (>12) hyperglycaemia were identified.
Table 1.
| Blood sugar (mmol/l) | Infusion rate (IU/hour) | Additional bolus (units) |
|---|---|---|
| < 4.0 | 0 | 0 |
| 4.1–6.9 | 1 | 0 |
| 7.0–8.9 | 2 | 0 |
| 9.0–11.9 | 3 | 5 |
| >12 | 4 | 10 |
Table 2.
| Blood sugar (mmol/l) | Start rate (IU/hour) | Sugar falling > 2/hour | Sugar fall 0.5–2/hour | Sugar stable | Sugar rising > 0.5/hour |
|---|---|---|---|---|---|
| > 9.1 | 4 | No change | No change | Increase by 50% | Double rate |
| 6.6–9.0 | 2 | Decrease by 30% | No change | Increase by 50% | Increase by 50% |
| 5.1–6.5 | 1 | Decrease by 50% | Decrease by 30% | No change | Increase by 50% |
| 3.0–5.0 | 0 | Decrease by 80% | Decrease by 50% | Decrease by 30% | No change |
Results and conclusion
The variable better controlled blood glucose (V = 6.5 ± 0.74; F = 7.0 ± 0.90) (P = 0.004) especially in patients with a high BMI (> 25) (Fig. 1). There were more hypos in F (n = 4) than V (n = 1). Glucose < 6 mmol/l was found for 33% of the time in F, 48% in V; < 8 mmol/l for 75% in F and 82% in V; <12 mmol/l for 99% in F and 99% in V.
Figure 1.
References
- Van den Berghe G. et al. Intensive insulin therapy in the critically ill patients. N Engl J Med. 2001;9:1359–1367. doi: 10.1056/NEJMoa011300. [DOI] [PubMed] [Google Scholar]