Dysnatremia at ICU admission and functional outcome of cardiac arrest: insights from four randomised controlled trials

Abstract

Purpose To evaluate the potential association between early dysnatremia and 6-month functional outcome after cardiac arrest. Methods We pooled data from four randomised clinical trials in post-cardiac-arrest patients admitted to the ICU with coma after stable return of spontaneous circulation (ROSC). Admission natremia was categorised as normal (135–145 mmol/L), low, or high. We analysed associations between natremia category and Cerebral Performance Category (CPC) 1 or 2 at 6 months, with and without adjustment on the modified Cardiac Arrest Hospital Prognosis Score (mCAHP). Results We included 1163 patients (581 from HYPERION, 352 from TTH48, 120 from COMACARE, and 110 from Xe-HYPOTHECA) with a mean age of 63 ± 13 years and a predominance of males (72.5%). A cardiac cause was identified in 63.6% of cases. Median time from collapse to ROSC was 20 [15–29] minutes. Overall, mean natremia on ICU admission was 137.5 ± 4.7 mmol/L; 211 (18.6%) and 31 (2.7%) patients had hyponatremia and hypernatremia, respectively. By univariate analysis, CPC 1 or 2 at 6 months was significantly less common in the group with hyponatremia (50/211 [24%] vs. 363/893 [41%]; P = 0.001); the mCAHP-adjusted odds ratio was 0.45 (95%CI 0.26–0.79, p = 0.005). The number of patients with hypernatremia was too small for a meaningful multivariable analysis. Conclusions Early hyponatremia was common in patients with ROSC after cardiac arrest and was associated with a poorer 6-month functional outcome. The mechanisms underlying this association remain to be elucidated in order to determine whether interventions targeting hyponatremia are worth investigating. Registration ClinicalTrial.gov, NCT01994772, November 2013, 21.

The Relationship between the Ratio of Urine Osmolality to Serum Osmolality and Neurological Outcomes in Out-of-hospital Cardiac Arrest Patients

“…It is inefficient to predict a patient’s prognosis with a CDI diagnosis in that the relevant guideline recommends predicting prognosis at least 72 h after the return to normothermia [ 2 ]. Additionally, hyponatremia was more prevalent than hypernatremia after ROSC [ 6 ], complicating the diagnosis of CDI, as hypotonic polyuria is not typically suspected, making water deprivation tests or desmopressin administration tests challenging. However, previous research has indicated that high SOsm and low UOsm are useful for predicting CDI [ 4 , 5 ].…”