Background:
Progressive ischemic brain injury after cardiac arrest can
cause damage to the hypothalamic-pituitary axis, particularly the pituitary
gland. This may impact serum osmolality (SOsm) and urine osmolality (UOsm) in
patients who have experienced out-of-hospital cardiac arrest (OHCA). We assumed
that a low ratio of UOsm to SOsm (USR) is related to poor outcomes among OHCA
patients. Therefore, the present study was designed to evaluate the association
between the USR within 72 h after the restoration of spontaneous circulation
(ROSC) and 6-month neurological outcomes in OHCA patients.
Methods:
This
prospective, observational study included OHCA patients with targeted temperature
management at Chonnam National University Hospital in Gwangju, Korea, between
January 2016 and December 2022. We collected SOsm and UOsm data at admission (T0)
and 24 (T1), 48 (T2), and 72 h (T3) after ROSC. The primary outcome was a poor
neurological outcome at 6 months defined by cerebral performance categories 3, 4,
or 5.
Results:
This study included 319 patients. The mean UOsm and USRs
at T0, T1, T2, and T3 of patients with poor outcomes were lower than those of
patients with good outcomes. Multivariable analysis indicated that the USRs at T1
(odds ratio [OR], 0.363; 95% confidence interval [CI], 0.221–0.594), T2 (OR,
0.451; 95% CI, 0.268–0.761), and T3 (OR, 0.559; 95% CI, 0.357–0.875) were
associated with a poor outcome. The areas under the receiver operating
characteristic curves of USRs at T0, T1, T2, and T3 for predicting poor outcomes
were 0.615 (95% CI, 0.559–0.669), 0.711 (95% CI, 0.658–0.760), 0.724 (95%
CI, 0.671–0.772), and 0.751 (95% CI, 0.699–0.797), respectively.
Conclusions:
The USRs within 72 h of ROSC were associated with poor
neurological outcomes at 6 months in OHCA patients.