Clinical Implications and Outcome Analysis of Dysnatremia in Critically Ill Patients in ICU in a Tertiary Care Hospital in Eastern India

INTRODUCTION: Serum sodium measurements are obtained routinely in intensive care unit (ICU) patient. Clinical manifestations of dysnatremia are primarily neurological and rapid changes can cause severe, permanent, even lethal brain injury(1). Hyponatraemia is associated with worse outcomes, particularly in patients with congestive heart failure(2) and cirrhosis.(3) Dysnatremia in ICUs is frequent in patients and may even be acquired during their stay(4–5). These patients have higher overall mortality, and importantly the slight changes are associated with an increased risk of death(6,7). We, therefore, used a prospective database of ICU patients to evaluate whether dysnatraemia is an independent risk factor for increased mortality in critically ill patients. OBJECTIVES: PRIMARY OBJECTIVE: To investigate the impact of incidental sodium disorders on 28-day mortality in critically ill patients. SECONDARY OBJECTIVES: Length of ICU stay, fluctuations in sodium level. MATERIALS AND METHODS: All adult patients admitted to the ICU for conditions were included excluding primary sodium disorders, those receiving 3% NaCl as cerebro-protective strategy, under 18 years of age, pregnant women, and those with end-stage renal disease on chronic dialysis. STUDY PERIOD: 6 months. PHASE 1: Observational. We Collected baseline data on serum sodium at ICU admission and monitored daily sodium levels till discharge or death or 28 day ICU stay. SODIUM DISORDER SEVERITY: MILD: Between 125 to 150 mEq/L or a deviation of less than 10 mEq/L from the normal range. MODERATE: Between 115 to 125 mEq/L or 150 to 160 mEq/L, or a deviation of 10 to 20 mEq/L from the normal range. SEVERE: Below 115 mEq/L or above 160 mEq/L, or a deviation of more than 20 mEq/L from the normal range. PHASE 2: Interventional. Application of sodium management protocols tailored to each severity category was recorded. Outcomes measures such as 28day mortality, ICU length of stay and fluctuations in sodium level were monitored. RESULTS: A total of 398 patients were included in the study, with 168 patients (42.2%) having dysnatremia and 230 patients (57.8%) without dysnatremia. Median age was similar between groups (51.5 vs. 54.0 years, p = 0.136). APACHE II scores were not significantly different between patients with and without dysnatremia (median 19.0 vs. 20.0, p = 0.344). The crosstab analysis demonstrated a significant association between dysnatremia and 28-day mortality (χ(2) = 26.82, p < 0.001). Among patients with dysnatremia, 45.24% (n = 76) succumbed to mortality, whereas the mortality rate in patients without dysnatremia was significantly lower at 20.43% (n = 47). ICU length of stay was significantly longer in patients with dysnatremia (median 9.0 vs. 8.0 days, p = 0.009). Patients with hyponatremia had a higher mortality rate (47.55%) compared to hypernatremia (30.43%). However, this difference was not statistically significant (χ(2) = 3.55, p = 0.170). Mortality was lower among patients receiving intervention (38.61%) compared to those not receiving intervention (57.14%), with a marginally significant difference (χ(2) = 5.55, p = 0.062). CONCLUSIONS: This study demonstrates that dysnatremia is a significant independent risk factor for increased 28-day mortality in critically ill patients admitted to the ICU.