Context
The hypothalamic-pituitary-adrenal axis is a major determinant of the
host response to stress. The relationship between its activation and patient
outcome is not known.Objective
To evaluate the prognostic value of cortisol levels and a short corticotropin
stimulation test in patients with septic shock.Design and Setting
Prospective inception cohort study conducted between October 1991 and
September 1995 in 2 teaching hospital adult intensive care units in France.Participants
A total of 189 consecutive patients who met clinical criteria for septic
shock.Intervention
A short corticotropin stimulation test was performed in all patients
by intravenously injecting 0.25 mg of tetracosactrin; blood samples were taken
immediately before the test (T0) and 30 (T30) and 60 (T60) minutes afterward.Main Outcome Measures
Twenty-eight–day mortality as a function of variables collected
at the onset of septic shock, including cortisol levels before the corticotropin
test and the cortisol response to corticotropin (Δmax, defined as the
difference between T0 and the highest value between T30 and T60).Results
The 28-day mortality was 58% (95% confidence interval [CI], 51%-65%)
and median time to death was 17 days (95% CI, 14-27 days). In multivariate
analysis, independent predictors of death (P≤.001
for all) were McCabe score greater than 0, organ system failure score greater
than 2, arterial lactate level greater than 2.8 mmol/L, ratio of PaO2 to fraction of inspired oxygen no more than 160 mm Hg, cortisol level
at T0 greater than 34 µg/dL and Δmax no more than 9 µg/dL.
Three groups of patient prognoses were identified: good (cortisol level at
T0 ≤34 µg/dL and Δmax >9 µg/dL; 28-day mortality rate,
26%), intermediate (cortisol level at T0 34 µg/dL and Δmax ≤9
µg/dL or cortisol level at T0 >34 µg/dL and Δmax >9 µg/dL;
28-day mortality rate, 67%), and poor (cortisol level at T0 >34 µg/dL
and Δmax ≤9 µg/dL; 28-day mortality rate, 82%).Conclusion
Our data suggest that a short corticotropin test has a good prognostic
value and could be helpful in identifying patients with septic shock at high
risk for death.
Figures in this Article
Septic shock remains the most common cause of death in noncoronary intensive
care units (ICUs).1 To tackle this problem,
numerous anti-inflammatory therapies have been tested during the past decade,
but all of them have been unable to improve survival in patients with severe
sepsis.2 Thus, there is an urgent need to better
characterize septic patients with the worst outcome. Several clinical prognostic
factors have already been identified (ie, preexisting underlying disease,
presence of organ dysfunction, and severity of illness scores).3
Moreover, the hormonal profile has been suggested to be a valid predictor
of outcome in critically ill patients.4 However,
a pathophysiologic derangement that could help identify a group of patients
who might benefit from a particular treatment has not been characterized yet.
The integrity of the hypothalamic-pituitary-adrenal (HPA) axis is a
major determinant of the host's response to stress.5- 6
During sepsis, the activation of the HPA axis is highlighted by increased
corticotropin release from the pituitary gland,7
enhanced adrenal secretory activity,8- 9
and high plasma cortisol levels.10- 13
However, whether endogenous glucocorticoid levels are adequate or constitute
an independent predictor of death remains controversial.10- 15
For instance, several studies showed that the higher the plasma cortisol concentrations,
the worse the patient's outcome.4,7,10,16- 18
In contrast, other studies reported lower cortisol levels in nonsurvivors
compared with survivors.19- 21
For this reason, in severe sepsis, the evaluation of the appropriateness of
the activation of the HPA axis requires dynamic testing. In this respect,
the most commonly used test is the short corticotropin stimulation test, normal
adrenal function being defined by a plasma cortisol level (before or at 30
or 60 minutes after the injection of corticotropin) above 20 µg/dL.22 However, basal plasma cortisol levels are commonly
greater than 20 µg/dL in severe sepsis and the use of the absolute increase
in plasma cortisol levels after the intravenous injection of corticotropin
may be more useful to evaluate adrenal function.12- 13
Indeed, occult adrenal insufficiency (ie, an absolute increment of cortisol
concentrations <9 µg/dL) after corticotropin may be associated with
impaired pressor responsiveness to norepinephrine23
and a high mortality rate.24- 25
Such results must be confirmed since other investigators have not found any
relationship between cortisol response to corticotropin and survival from
sepsis.26
In the context of renewed interest in corticosteroids as therapy for
septic shock,14- 15,21,23- 25,27- 30
we undertook a prospective study to determine the incidence of occult adrenal
insufficiency in septic shock patients and to assess the factors associated
with mortality, taking special interest in cortisol levels and cortisol response
to corticotropin.