GH and cortisol secretion in patients with burn on day 7 after thermal injury

Objectives

Hormonal and nutritional changes occur in burns patients, in whom low IGF-I and high cortisol levels are commonly reported during the first 2 weeks after the burn event. However, conflicting data about GH secretion are still present. In fact, high GH levels have been reported by some but not by other authors. Aim of this study was to define growth hormone (GH) and cortisol (F) secretion during a 12-h period on day 7 after a major burn in man.

Methods

In 5 patients with major burn injury (BURN, age, mean ± SEM: 35.5 ± 5.4 years; BMI: 27.1 ± 2.3 kg/m²; burn area: 36.5 ± 5.5%; ROI score: 0.3 ± 0.1) serum GH and cortisol levels were evaluated every 20 min from 7.00 am to 7.00 pm on day 7 after burn unit (BU) admission, during parenteral and/or enteral nutrition and dopamine infusion (5–10 μg/kg/min). The same hormonal evaluation was performed in six normal fed adult subjects (NS, age: 30.2 ± 2.5 years; BMI: 22.3 ± 2.6 kg/m²). IGF-I levels were also evaluated at 7.00 am on day 7 after BU admission in BURN and basally in NS.

Results

On day 7 after BU admission. IGF-I levels in BURN were lower than in NS (90.5 ± 12.3 vs 210.6 ± 12.8 μg/l, P < 0.05). On the contrary, mean serum (GH levels in BURN (solid circles) were higher than in NS (open circles) (mean GH levels: 2.8 ± 1.5 vs 0.4 ± 0.1 μg/l, P < 0.001; AUC: 85.7 ± 41.9 vs 21.7 ± 6.7 μg/l/h, P < 0.001). Particularly, GH secretion in BURN was normally pulsatile with elevated baseline GH levels. Also mean F levels BURN were elevated and higher than in NS (mean F levels: 241.7 ± 39.9 vs 84.4 ± 17.1 μg/l. P < 0.001; AUC: 15093.3 ± 3112.4 vs 5048.6 ± 1030.8 μg/l/h, P < 0.001). with high levels even in the late afternoon and loss of circadian rhythm.

Conclusion

Our data show that in burns patients on day 7 after BU admission. GH as well as cortisol secretion are markedly higher while IGF-I levels are clearly lower than in NS. These findings confirm the existence of peripheral GH resistance in critical illness together with adrenal axis hyperactivity. Peripheral GH resistance and hypercortisolism could likely contribute to impair recovery from the catabolic state in the early phase after thermal injury.

Figure.

Modified Macintosh Blade with right catheter ballooninflated with 2 ml air and automatic angle finder