Endocrine Abstracts

Introduction

Severe physical, and psychiatric illnesses are characterised by high cortisol levels and disturbance in circadian rhythm. A distinct awakening cortisol response and a marked diurnal decline is reported to be associated with better physical and psychological health, deviations from this pattern are negative for health. It is however not known if ITU patients have any specific cortisol pattern associated with their altered sleep awakeness cycles and if these are related to the degree of sedation and activity.

Aim of the study

To determine the cortisol patterns in critically ill patients admitted to ITU and determine the influence of degree of sedation and significant activity on cortisol levels.

Materials and Methods

Thirteen consecutive patients not on steroids or having immunosuppressive conditions admitted to ITU over a 6-month period at West Wales General Hospital were included in the study. Samples of blood were collected at 4 hourly intervals over a 24-hour period. All other relevant patient data including the sedation scores and details of significant physical activity were recorded. The data was then analysed to see the cortisol patterns over the 24-hour period and its relationship to Ramsay sedation scores, time and activity.

Results

The mean cortisol level of 400–500 nmol/l were within the normal range of peak circadian levels but there was no consistent pattern of circadian variation. The cortisol levels appeared to have a strong relationship with Ramsay sedation scoring (P value<0.0001). At low sedation scores the cortisol expression was high (700 nmol/l) and progressively decreased to levels of up to 300 at a score of 6. This association was not related to passive activities or posture or time.

Conclusion

The cortisol circadian rhythm is disturbed in critically ill patients with altered sleep awakeness patterns. There appears to be a significant correlation of cortisol level to sedation score as demonstrated by our study. Thus degree of sedation may be useful to modulate the cortisol levels to mimic a physiological pattern associated with overall well-being.