Hypertonic saline attenuates the hormonal response to injury

We reported previously in a randomized double-blinded study in 20 postoperative coronary bypass patients that hypertonic saline (1.8% NaCl, HS) provides early hemodynamic benefits, increased osmolality and net negative fluid balance compared to 0.9% NaCl (NS). To investigate the effects of HS on the hormonal response to injury, we measured ACTH, cortisol, angiotensin II (AII), aldosterone, vasopressin (AVP), and atrial natriuretic factor (ANF) in these patients. ACTH and cortisol concentrations increased in the NS group but were suppressed in the HS group (p less than 0.05). Aldosterone increased in NS patients, but was suppressed in HS patients (HS: delta Aldosterone 13.0 +/- 3.0 vs. NS: delta Aldosterone 26.0 +/- 7.0 ng/dl, p less than 0.05). The AII response was suppressed at six and eight hours (p less than 0.05) in patients receiving HS but did not change in patients receiving NS. ANF did not change significantly for either group. The significant increases in AVP were similar in both groups (p less than 0.05), but correlated with increases in osmolality only in the NS group (r = 0.8, p less than 0.009). Other than AVP, HS suppressed the responses of some of the hormones that normally increase in response to injury, relative to NS. Attenuation of the neuroendocrine response and other previously reported effects of HS suggest that HS may be an efficacious solution for resuscitation in the postoperative and postinjury period.