Pulse pressure variation and adrenal insufficiency in septic shock
© BioMed Central Ltd. 2007
Published: 22 March 2007
It is known that corticosteroid therapy improves the hemodynamic state in patients with septic shock and relative adrenal insufficiency. This effect is partially due to a direct action on vascular tone in the more vasoplegic patient, so they may be more hypovolemic. We tried in this study to determine whether pulse pressure variation measured just before the adrenocorticotropin test can predict the adrenal state.
During a period of 3 years (January 2001–December 2003) we realized a prospective observational study. All patients having septic shock were enrolled. Patients with arrhythmia were excluded. We measured hemodynamic data (mean arterial pressure (MAP), pulse pressure variation (ΔPP)), then we realized an ACTH short test (injection of 250 mg ACTH with dosage of the cortisol level before the injection, at 30 and 60 minutes).
One hundred and one patients were enrolled. Age was 48 ± 17 years. SAPS II = 45 ± 16, APACHE II score = 18 ± 8, MAP = 52 ± 12 mmHg, lactate = 3.5 ± 2 mmol/l, and basal cortisol level (BCL) = 278 ± 143 μg/l. We divided all patients into two groups using the ΔPP cutoff: <12% (n = 30) and ≥12% (n = 71). There is no difference in the two groups in age, SAPS II, and MAP. Patients with low ΔPP (<12%) have a significantly (P = 0.01) low BCL: 204 ± 127 μg/l vs 291 ± 133 μg/l, a low increase of cortisol level in response to ACTH: 264 ± 144 μg/l vs 369 ± 142 μg/l (P = 0.02), and a low maximum variation after the ACTH test: 59 ± 52 μg/l vs 79 ± 63 μg/l (not significant). The relative adrenal deficiency (Δmax < 90 μg/l) is more frequent in patients with low ΔPP: 80% vs 60%. Survival is lower in the low ΔPP group, 13% vs 40%.
Patients with low ΔPP seem to be of poor prognosis because they have a low BCL, a low maximum cortisol increase after the ACTH test, and a high death rate. Annane and colleagues  found that nonsurvivors have low MAP, high lactate level, high basal cortisol level and low maximum cortisol level increase after the test compared with survivors. This finding is in contrast to our patients.
Patients with low ΔPP before realizing the ACTH test tend to have more probability of adrenal deficiency, have more probability to receive corticosteroid and have poor prognosis.