The study aimed to determine the prevalence of electrolyte disturbances in hospitalized children in PICU and related factors. The frequency of electrolytes was significantly different among the age groups, sex (except for potassium), duration of and causes of hospitalization, but significant difference found in hyponatremia and hypernatremia in outcome (deceased and alive). The prevalence of sodium, calcium, and magnesium electrolyte disorders in children was not significantly different from diuretic, aminoglycoside and digitalis medication. However, hyperkalemia was significantly higher in children with diuretic use than in other children.
Mokhtari et al. showed that mortality rate was higher in patients with hyponatremia (34% vs. 16%) and hypernatremia (55% vs. 18%) than in other patients significantly. The mortality rate in the hypernatremic group was higher than the hypothermic group, and both were higher in patients with no disorder significantly. It was found that sodium disorders are common in ICU patients. These disorders are associated with increased mortality and are more common in older ages; moreover, mortality rates are higher in hypernatremia (
4). The results of this study are similar to those of our study.
Studies have shown that hypernatremia associated with higher mortality and morbidity in general and surgical care units (
14,
15) ranging from 40 to 60% with an increased risk of mortality (
14), which is associated with mortality rates in the present study.
Aiyagari et al. (
15) showed that although the mortality rate increased with hypernatremia (30.1% vs. 10.2%) in patients who were admitted to the surgical intensive care unit, only severe hypernatremia increased independently from mortality and morbidity enhancement. A study has shown that the mortality rate in patients with hypernatremia is 39% during admission and 43% in admission, which is significantly higher than in patients without hypernatremia (24%) (
3). A study has also highlighted the role of hypernatremia as an independent predictor of mortality. Lindner et al. (
3) showed that hypernatremia in the general health care unit is an independent risk factor for prediction of mortality (odds ratio of 2.1). The present study found that the frequency of hypernatremia and hyponatremia was significantly higher in children who died, similar to the mentioned studies. On the other hand, acute hyponatremia can lead to death if brain edema is not treated promptly. Conversely, if chronic hyponatremia is rapidly corrected, osmotic demyelination occurs which is potentially fatal. Typically, hyponatremia is a predictor of mortality in patients with advanced heart failure and cirrhosis. In these circumstances, it is generally assumed that hyponatremia indicates the severity of the underlying disease rather than direct involvement in mortality. As summing the same subject, recently reported an association between hyponatremia and mortality in patients with pulmonary embolism, pulmonary hypertension, pneumonia, and myocardial infarction (
16).
Recent data show that chronic mild hyponatremia is associated with mortality in the general population (
17). Our study also found that hyponatremia was far more than hypernatremia in children who had died. Therefore, one of the predictors of mortality in children admitted to ICU is sodium, which is necessary for regulating this electrolyte in patients.
Subba and Thomas et al. (
18) reported that all children admitted to the pediatric ICU had a high frequency of electrolyte and prognosis disorders, of which 32.45% had at least one electrolyte disturbance in which 7.9% had a combination of electrolyte disturbances. Hypercalcemia was 14.4%, hyponatremia 9.5%, hypernatremia 4.9%, and hypocalcaemia 3.6%.of 24.2% of deceased patients, 46% hyperkalemia, 25% hyponatremia, 8% hypernatremia and 12.5% hypocalcemia. Our study also found that 20.1% of children had hyponatremia, 16.9% had hypernatremia, 4.3% had hypokalemia, 33.9% had hyperkalemia, 56.6% had hypocalcemia, 0.5% had hypercalcemia, 13.8% had hypomagnesemia and 2.3% had hypermagnesemia. Unlike the study though, we found that only sodium was associated with mortality among the electrolytes. The reason for this difference may be due to the difference in the sample size, the difference in the demographic characteristics of patients, the difference in entry and exit criteria, and the reason for the admission of the subjects. At the same time, as noted earlier, some scholars believe that partly because of hypernatremia as a part of patient care in ICU (
11,
15,
18), this partial difference may indicate a lower level of patient care standards in the center. Of course, it should not be overlooked that hypernatremia is a problem in the ICU. Studies have shown that despite repeated measurements of sodium in the ICU, the incidence of hypernatremia is still prevalent, and primary care is often inadequate and delayed (
18).
In a study conducted by Luu et al. (
19) on 102 patients between 1 month and 2 years of age resulted that hyponatremia prevalence was 22%, which had no relation to epilepsy, intubation, and corticosteroid use (
20). The results of this study are in line with our findings. A study by Dias et al. (
20) was conducted on 337 children and examined the concentration of ionized calcium over a period of ten days and associated organ dysfunction. The results of this study were interpreted based on age, nutrition, sepsis and the use of steroid. Resulted that 77.5% of these people had hypocalcaemia, of which 95% of them had an organic disorder that is independent of hypocalcemia. Medicines that produce hypocalcaemia are methylprednisolone (dosage greater than 2 mg/kg/day) and furosemide (more than 2 mg/kg/day). In this study, there was no definitive association between hypocalcemia and mortality. In our study, it was found that 56.6% of patients had hypocalcemia, 0.5% had hypercalcemia, and similar to the mentioned study, there was no significant relationship between calcium disorder and mortality.
Zahedi (
21) aimed to investigate the prevalence of electrolyte disturbances and its association with mortality. They found out that 69% of the patients had hyponatremia, 14% normal and 17% hypernatremia, 36% had hypokalemia, 43% normalized and 21% had hyperkalemia, and 33% had hypomagnesemia, 58% normal and 9% hypermagnesemia. Based on the findings of this study, it can be concluded that there is a significant relationship between mortality and sodium and magnesium electrolytes, but there is no significant correlation with potassium electrolyte disturbances.
Our study also found that 20.1% of children had hyponatremia, 16.9% had hypernatremia, 4.8% had hypokalemia, 33.9% had hyperkalemia, 56.6% had hypocalcemia, 0.5% had hypercalcemia, 13.8% had hypomagnesemia and 2.3% had hypomagnesemia. Although unlike the study, we found that only sodium was associated with mortality among the electrolytes. The reason for this difference may be due to the difference in the sample size, the difference in the demographic characteristics of patients, the difference in entry and exit criteria, and the reason for the admission of the subjects.
In a study by Bindu and Beeregowda (
22) to examine the association of sodium with prognosis in children who were admitted to the ICU. A total of 152 patients between 1 and 14 years were studied. The prevalence of hyponatremia was 33.5%. Of the 51 cases, hyponatremia was 25.49% moderate hyponatremia and 13.73% severe hyponatremia. The prevalence of hyponatremia in bronchopneumonia was 41.3% and acute encephalitis was 24%. The duration of hospitalization (day) was higher in cases of severe hyponatremia than in cases of moderate hyponatremia. At the end of the study, one third of PICU-treated patients had hyponatremia. By adding more hyposmotic fluid, it is more likely that the percentage of children with hyponatremia will increase. The results of the Bindu and Beeregowda (
22) study were consistent with the findings of our study. However, in our study, there was no significant difference in the duration of admission in terms of sodium level. Then again, intense hyponatremia can prompt demise if cerebrum edema is not dealt with instantly. On the other hand, if chronic hyponatremia is quickly revised, osmotic demyelination happens which is possibly lethal. Regularly, hyponatremia is an indicator of mortality in patients with advanced heart problems and cirrhosis. In these conditions, it is commonly expected that hyponatremia shows the seriousness of the underlying pathology as opposed to contribution in mortality. Expecting a similar subject, ongoing reports have mentioned the relationship between hyponatremia and mortality in patients with pulmonary embolism, pulmunary hypertension, pneumonia, and myocardial infarction.
5.1. Study Limitations
The main study limitation was lack of proper cooperation of the parents of participants that decreased the sample size.
5.2. Conclusions
From the study, it was concluded that the frequency of electrolyte disturbances was not significantly different between the age groups, sex (except for potassium), duration of admission and the cause of hospitalization, but it was found that the frequency of hyponatremia and hypernatremia in deceased children was significantly more than alive children. The prevalence of sodium, calcium, and magnesium disorders in children was not significantly different from diuretic, aminoglycoside and digitalis medications. However, the rate of hyperkalemia was significantly higher in children with diuretic use than in other children who did not use diuretic (furosemide). The main reason probably is due to higher creatinine in hyperkalemia.