TAIPEI, Taiwan, Feb. 2 - ICU patients with adrenal insufficiency stand a better chance of being weaned off a ventilator more rapidly if they are treated with hydrocortisone before extubation is attempted.
So reported Chung-Jen Huang M.D., and Horng-Chyuan Lin, M.D., of Chang Gung Memorial Hospital here in the first February issue of the American Journal of Respiratory Care and Critical Medicine.
In this randomized study of 93 critically ill patients, 91.4% of the 70 with relative adrenal insufficiency who received hydrocortisone infusions were successfully weaned from a ventilator, compared with 68.8% of those who received a saline placebo. In comparison, 88.4% of those with adequate adrenal reserves could be successfully taken off ventilator support.
Action Points
- Be aware that this study suggests that giving hydrocortisone infusions to patients with relative adrenal insufficiency who are on mechanical ventilators may help them to be successfully weaned off ventilator support.
- Be aware that the authors found 70 cases of relative adrenal insufficiency in a population of 93 patients, suggesting that the condition is common among critically patients.
"In this study, stress dose corticosteroid supplementation before extubation of patients with adrenal insufficiency led to a significantly higher success rate for ventilator weaning and a shorter weaning duration than in the placebo group," they wrote.
Subnormal corticosteroid production during critical illness, particularly septic shock, in the absence of structural defects in the hypothalamic-pituitary-adrenal axis has been termed "functional adrenal insufficiency," or "relative adrenal insufficiency," and is being found with increasing frequency in ICUs. Several definitions have been proposed, including levels including a basal cortisol level of less than 20, 25 or 30 mcg/dL or an incremental response of less than 9 mcg/dL (250 nmol/L) after cosyntropin stimulation.
The investigators used morning cortisol levels and ACTH stimulation tests to determine adrenal reserves before extubation, allowing them to show an association between adrenal insufficiency and extubation outcomes.
"The results suggest that evaluation of adrenal function before weaning is useful in routine ICU practice," Dr. Huang and Dr. Lin wrote.
Their prospective, randomized, placebo-controlled, double-blind study of 93 ICU patients who had been under mechanical ventilation via endotracheal tube for at least 72 hours. All patients were recovering from the primary etiology of respiratory failure and had been off vasopressor agents and sedatives for at least 24 hours before the start of the study. The patients were all hemodynamically stable, neurologically intact (Glasgow coma score more than 11), and were ready to be weaned off ventilator.
The patients received regular corticosteroids before or during the admission, and those who did not have an adequate cough reflex were excluded.
When the patients met weaning criteria, the investigators checked morning cortisol levels. Plasma cortisol concentrations above 25 mcg/dL (694 nmol/L) were considered to indicate intact adrenal function.
If the morning cortisol level was below 25 mcg/dL, the authors then performed a high-dose ACTH stimulation test. They defined an intact adrenal reserve as an increase in serum cortisol of greater than 9 mcg/dL (250 nmol/L); an increase lower than that was defined as adrenal insufficiency.
Patients with insufficiency were then randomized to receive either 50 mg intravenous hydrocortisone every six hours during the weaning period or a saline placebo on the same schedule.
When the weaning period ended all patients with adrenal insufficiency were shifted to 75 mg of oral cortisone acetate in the morning and 37.5 mg in the afternoon.
"The successful ventilator weaning percentage was significantly higher (p = 0.035) in the adequate adrenal reserve group (88.4%) and in the stress dose hydrocortisone treatment group (91.4%) than in the placebo group (68.6%)," the authors wrote.
Among the patients with adrenal insufficiency, 32 of 35 patients taking hydrocortisone were successfully taken off ventilators, compared with 24 of 35 in the control group. Among the 20 patients with adequate adrenal reserves, 20 of 20 patients were taken off ventilator, but three failed after extubation.
"The weaning period was shorter in the hydrocortisone treatment group than in the placebo group," they noted. "No significant adverse effects were observed in the corticosteroid treatment group."
On the basis of the results of the study, the authors recommended evaluation of adrenal status for all patients before extubation.
The primary limitation of this study was its small size. A larger multicenter trial of hydrocortisone-aided ventilator weaning is under way.
Primary Source
American Journal of Respiratory and Critical Care Medicine
Source Reference: Huang C and Lin H. Am. J. Respir. Crit. Care Med .2006; 173: 276-280.