Increased sodium intake and decreased sodium excretion in ICU-acquired hypernatremia: A prospective cohort study

Severe intensive care unit-acquired hypernatraemia: Prevalence, risk factors, trajectory, management, and outcome

Background

Severe intensive care unit-acquired hypernatraemia (ICU-AH) is a serious complication of critical illness. However, there is no detailed information on how this condition develops.

Objectives

The objective of this study was to study the prevalence, risk factors, trajectory, management, and outcome of severe ICU-AH (≥155 mmol·L-1).

Methods

A retrospective study was conducted in a 40-bed ICU in a university-affiliated hospital. Assessment of sodium levels, factors associated with severe ICU-AH, urinary electrolyte measurements, water therapy, fluid balance, correction rate, and delirium was made.

Results

We screened 11,642 ICU admissions and identified 109 patients with severe ICU-AH. The median age was 57 years, 63% were male, and the median Acute Physiology and Chronic Health Evaluation III score was 64 (52; 80). On the day of ICU admission, 64% of patients were ventilated; 71% received vasopressors, and 22% had acute kidney injury. The median peak sodium level was 158 (156; 161) mmolL-1 at a median of 4 (1; 11) days after ICU admission. Only eight patients (7%) had urine sodium measurement (median concentration: 17 mmol·L-1). On the day of peak hypernatraemia, 80% of patients were unable to drink due to invasive ventilation; 34% were on diuretics; 25% had fever, and 50% did not receive hypotonic fluids. When available, the median electrolyte-free water clearance was -1.1 L (-1.7; -0.5), representing half of the urine output. After peak hypernatraemia, the correction rate was -2.8 mmol·L-1 per day (95% confidence interval: [-2.9 to -2.6]) during the first 3 d.

Conclusions

Severe hypernatraemia occurred in the setting of inability to drink, near-absent measurement of urinary free water losses, diuretic therapy, fever, renal impairment, and near-absent or limited or delayed water administration. Correction was slow.

Catabolism highly influences ICU-acquired hypernatremia in a mainly trauma and surgical cohort

PURPOSE

To further analyse causes and effects of ICU-acquired hypernatremia.

METHODS

This retrospective, single-centre study, analysed 994 patients regarding ICU-acquired hypernatremia. Non-hypernatremic patients (n = 617) were compared to early-hypernatremic (only before ICU-day 4; n = 87), prolonged-hypernatremic (before and after ICU-day 4; n = 169) and late-hypernatremic patients (only after ICU-day 4; n = 121). Trends in glomerular filtration rate (eGFR), urea-to-creatinine ratio (UCR), fraction of urea in total urine osmolality and urine sodium were compared. Risk factors for i) the development of hypernatremia and ii) mortality were determined.

RESULTS

Thirty-eight percent (n = 377) developed ICU-acquired hypernatremia. Specifically in the prolonged- and late-group, decreased eGFRs and urine sodium but increased UCR and fractions of urea in urine osmolality were present. Decreased eGFR was a risk factor for the development of hypernatremia in all groups; disease severity and increased catabolism particularly in the prolonged- and late-hypernatremic group. Increased age, SAPS-III and signs of catabolism but not the development of hypernatremia itself was identified as significant risk factor for mortality.

CONCLUSIONS

Late- and prolonged-hypernatremia is highly related to an increased protein metabolism. Besides excessive catabolism, initial disease severity and a decrease in renal function must be considered when confronted with ICU-acquired hypernatremia.

Chloride, Sodium and Calcium Intake Are Associated with Mortality and Follow-Up Kidney Function in Critically Ill Patients Receiving Continuous Veno-Venous Hemodialysis-A Retrospective Study

BACKGROUND

Studies on the association between solute, nutrition and fluid intakes and mortality and later kidney function in critically ill acute kidney injury (AKI) patients receiving continuous veno-venous hemodialysis (CVVHD) are scarce.

METHODS

Altogether, 471 consecutive critically ill AKI patients receiving CVVHD in the research intensive care unit (ICU) were recruited in this single-center, retrospective study.

RESULTS

The median age was 66 (58-74) years, and 138 (29.3%) were female. The 90-day and one-year mortalities were 221 (46.9%) and 251 (53.3%), respectively. After adjusting for age, sex, Acute Physiology and Chronic Health Evaluation II (APACHE) score, coronary artery disease, immunosuppression, ICU care duration, mechanical ventilation requirement, vasopressor requirement and study time period, the cumulative daily intake of potassium, chloride, sodium, phosphate, calcium, glucose, lipids and water was associated with one-year mortality in separate multivariable cox proportional hazards models. In a sensitivity analysis excluding patients who died within the first three days of ICU care, the daily intake of chloride (hazard ratio (HR) 1.001, confidence interval (CI) 95% 1.000-1.003, p = 0.032), sodium (HR 1.001, CI 95% 1.000-1.002, p = 0.031) and calcium (HR 1.129, CI 95% 1.025-1.243, p = 0.014) remained independently associated with mortality within one-year in the respective, similarly adjusted multivariable cox analyses. The cumulative daily intake of chloride, sodium, calcium and water was independently associated with the estimated glomerular filtration rate (eGFR) at 90 days follow-up in separate substantially adjusted multivariable cox proportional hazards models.

CONCLUSION

The cumulative daily intake of chloride, sodium and calcium is associated with mortality and daily chloride, sodium, calcium and water intake is associated with follow-up eGFR in critically ill patients with CVVHD-treated AKI.

[Hypo- and hypernatremia in the intensive care unit : Pitfalls in volume management]

Hypo- and hypernatremias are very frequent in intensive care unit (ICU) patients and are closely related to volume disturbances and volume management in the ICU. They are associated with longer ICU stays and significant increases in mortality. Treating them is more complex than it may initially appear. Hyponatremias are differentiated based on tonicity and volume status. With hypertonic and isotonic hyponatremias, the primary focus of treatment is the underlying hyperglycemia. In case of hypotonic hypovolemic hyponatremia, the condition is treated with balanced crystalloid solutions. In eu-/hypervolemic hypotonic hyponatremias acute treatment with hypertonic saline is necessary. Hypervolemic hypernatremia occurs almost exclusively in ICU patients, often due to infusion of hypertonic solutions. There is little evidence to guide treatment, although hypotonic infusions in conjunction with diuretics may represent a legitimate approach. Great emphasis should be placed on prevention and the infusion of hypertonic solutions should be avoided. Disturbances in plasma sodium concentrations are common, requiring close attention. Exact diagnostic classification needs to be made and volume managed accordingly.