Electrolyte balance plays a crucial role in maintaining cellular function and systemic homeostasis, especially in critically ill pediatric patients. In the Pediatric Intensive Care Unit (PICU), disturbances in electrolyte levels are frequent and can significantly affect clinical outcomes, including morbidity and mortality. Common electrolyte abnormalities seen in the PICU include low or high sodium levels (hyponatremia and hypernatremia), low or high potassium levels (hypokalemia and hyperkalemia), hypocalcemia, and hypomagnesemia. These imbalances may result from the underlying disease, therapeutic interventions, or inadequate fluid and electrolyte management during hospitalization.

Children admitted to the PICU often present with conditions such as sepsis, acute kidney injury, respiratory failure, and gastrointestinal disorders, all of which are known to disrupt electrolyte balance [2]. Among these, hyponatremia is one of the most frequently observed disturbances and is associated with a longer hospital stay and adverse neurological outcomes[3]. Likewise, abnormalities in potassium levels, both low and high, are linked to serious cardiac complications, including arrhythmias, which can be fatal if not promptly corrected[4].

Research has shown that electrolyte imbalances not only reflect the severity of illness but can also worsen the patient’s condition by aggravating underlying disease processes. Timely identification and correction of these imbalances are essential for improving outcomes in the PICU. For instance, a prospective study by Mathew et al. (2021) in an Indian PICU reported electrolyte abnormalities in over 60% of critically ill children at the time of admission, highlighting the high burden and clinical relevance of these disturbances[5].

Despite their significance, electrolyte disorders are often under-recognized, particularly in resource-limited settings. This underscores the importance of local data to better understand the prevalence and patterns of electrolyte abnormalities in specific populations. Moreover, the relationship between these imbalances and clinical parameters such as illness severity, diagnosis, and outcomes remains underexplored in many tertiary care centers in India[6].

This study was therefore conducted to examine the common types and frequencies of electrolyte imbalances in critically ill children admitted to a tertiary care PICU. By identifying prevalent disturbances and their clinical associations, the study aims to support timely diagnosis and management, potentially improving outcomes in pediatric critical care.

This was a hospital-based, cross-sectional observational study conducted in the Pediatric Intensive Care Unit (PICU) of the Department of Pediatrics at, a tertiary care teaching hospital in Niloufer Hospital, Osmania Medical College, Hyderabad, India. The study was conducted over a period of 18 months,

Study Population

All critically ill children aged 1 month to 14 years admitted to the PICU during the study period were eligible for inclusion. A total of 300 children who met the inclusion and exclusion criteria were enrolled in the study.

Inclusion Criteria

• Study group included children aged > 1 month and < 14 years who seek emergency care in PICU, irrespective of their primary diagnosis and the severity of the illness.
• Informed written consent obtained from parents or legal guardians.

Exclusion Criteria

• Children aged < 1 month and> 14 years
• All children with diarrhea
• Post-Operated cases
• Post-Resuscitated cases
• Children treated prior to PICU admission
• Children who expired within 1 hour of admission

Data Collection

After obtaining ethical clearance from the Institutional Ethics Committee (IEC), data were collected using a pretested structured proforma. The following parameters were recorded:

1. Demographic details: Age, sex, Etiology on admission.
2. Laboratory parameters: Serum electrolytes including sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺),

measured within the first 24 hours of admission using an automated electrolyte analyzer.

Electrolyte values were classified based on reference pediatric ranges. Abnormal values were categorized as:

• Hyponatremia: Serum sodium < 135 mEq/L
• Hypernatremia: Serum sodium > 145 mEq/L
• Hypokalemia: Serum potassium < 3.5 mEq/L
• Hyperkalemia: Serum potassium > 4.5 mEq/L
• Hypocalcemia: Total serum calcium < 8.0 mg/dL
• Hypercalcemia: Serum calcium > 10.5 mg/dL

Outcome Measures

• Prevalence of electrolyte abnormalities on admission.
• Association of electrolyte imbalance with clinical parameters such as diagnosis, severity of illness, duration of stay, and outcome (recovery/discharge vs. death).

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using IBM SPSS Statistics version 25. Descriptive statistics were used to summarize the data (mean ± SD for continuous variables, frequencies, and percentages for categorical variables). Association between electrolyte imbalance and clinical outcomes was assessed using the Chi-square test or Fisher’s exact test for categorical variables and Student’s t-test for continuous variables. A p-value of <0.05 was considered statistically significant.

Table 1: Demographic distribution among study population

The demographic characteristics and patterns of electrolyte imbalance among children admitted to a tertiary care Pediatric Intensive Care Unit (PICU). Among the 300 children included in the study, the largest age group comprised infants aged 1 month to 1 year (30.6%), closely followed by those aged 1 to 5 years (29.3%). There was a slight male predominance with 56% males and 44% females. The most common underlying etiologies for PICU admission were central nervous system (CNS) disorders (29.3%), followed by respiratory illnesses (18%), infections (12.3%), and endocrine disorders (10.3%), suggesting a diverse clinical profile among the critically ill pediatric population.

Table 2: Electrolytes distribution among study population

Electrolyte imbalance was a prominent finding in this study. Hyponatremia emerged as the most frequent sodium abnormality, present in 27.67% of children, while 64.67% had normal sodium levels and 7.67% had hypernatremia. Potassium levels were abnormal in a significant number of patients; 16% had hypokalemia and 10% had hyperkalemia, while 74% maintained normal potassium levels. Calcium disturbances were notable, as 18% had hypocalcemia, although hypercalcemia was rare (0.3%), and 81.7% had normal calcium levels. These results indicate that hyponatremia, hypokalemia, and hypocalcemia were the most prevalent electrolyte imbalances observed in the PICU setting.

Table 3: Electrolytes distribution among different age groups

When analyzed across age groups, no statistically significant differences were found for any electrolyte imbalance (p > 0.05), implying that the prevalence of such imbalances was fairly uniform across different pediatric age categories. Notably, while infants and young children showed a slightly higher frequency of hyponatremia and hypokalemia, the differences were not significant, suggesting that all pediatric age groups are equally vulnerable to these derangements when critically ill.

 Table 4: Electrolytes distribution among outcome of study population

A comparison of electrolyte abnormalities between improved and non-surviving patients revealed a significant association between potassium levels and outcomes. Hypokalemia were significantly more common in children who did not survive (p < 0.0001), indicating a strong prognostic correlation. On the contrary, no statistically significant associations were found between sodium and calcium levels and patient outcomes, although hyponatremia and hypocalcemia were relatively more frequent among non-survivors. These findings underscore the importance of potassium homeostasis in critically ill pediatric patients, as disturbances in serum potassium were strongly associated with adverse outcomes.

Electrolyte imbalances are common in critically ill children and often contribute to significant morbidity and mortality. In our study comprising 300 PICU admissions, a considerable proportion of patients exhibited disturbances in serum sodium, potassium, and calcium, levels aligning with findings from previous literature.

Demographic Profile and Etiologies

Infants aged between 1 month to 1 year were the most frequently admitted age group (30.6%), followed by those aged 1–5 years (29.3%). The observed male predominance (56%) aligns with several Indian studies that report similar gender distributions in PICUs, possibly reflecting health-seeking behavior and societal gender biases [7].

CNS disorders (29.3%) were the leading cause of PICU admission, followed by respiratory (18%) and infectious (12.3%) conditions. This distribution reflects global patterns of pediatric critical illness, where respiratory and neurologic causes dominate pediatric ICU admissions [8].

Electrolyte Disturbances

Sodium Imbalance

Hyponatremia was the most prevalent sodium disturbance (27.67%), a finding consistent with other PICU-based studies, such as that by Singhi et al., who reported hyponatremia in up to 35% of critically ill children [9]. The causes may include inappropriate antidiuretic hormone secretion, renal losses, or dilutional states from fluid resuscitation.

Although hypernatremia was less frequent (7.67%), its presence still demands attention due to its strong association with mortality in other studies [10]. In our cohort, there was no statistically significant association between sodium imbalance and mortality (p=0.165), but non-survivors did exhibit a higher incidence of both hypo- and hypernatremia.

Potassium Imbalance

Potassium disturbances were notably significant in our study. Hypokalemia (16%) and hyperkalemia (10%) were both observed, with a statistically significant correlation between potassium abnormalities and mortality (p < 0.0001). This finding underscores the critical role of potassium in maintaining cardiac rhythm and neuromuscular function, where disturbances can lead to fatal arrhythmias [11].

Our data support previous studies, such as those by Mahajan et al., who observed high mortality among children with serum potassium abnormalities [12]. Potassium derangements serve as potential prognostic indicators in PICU settings.

Calcium Imbalance

Hypocalcemia was present in 18% of the population, a finding in concordance with previous Indian data [13]. However, in our study, calcium levels did not significantly correlate with outcomes (p=0.597), despite a slightly higher frequency among non-survivors.

Hypocalcemia is frequently seen in critically ill children due to sepsis, renal dysfunction, or blood transfusions. Still, unlike potassium, it may not be independently predictive of poor outcomes unless profoundly low [14].

Electrolyte Imbalance by Age

The study did not find statistically significant variations in the prevalence of electrolyte abnormalities across different pediatric age groups (p > 0.05 for all). This uniformity highlights that critically ill children, irrespective of age, are equally susceptible to electrolyte derangements—a finding also noted by Atkinson and Murtagh in their multicenter study [15].

Duration of Hospital Stay

The mean duration of PICU stay was prolonged in patients with hyponatremia  (6.11±2.08days) as compared to normonatremic (4.68±4.84) and hypernatremic patients (5.50±3.51) in our study. Rao SSD et al[16] found similar results with mean duration of PICU stay prolonged in hyponatremic(4.69±4.04) in comparison with hypernatremic (4.35±4.24) and normonatremic (3.3±3.02) .

Clinical Implications

Our findings emphasize the need for early recognition and correction of potassium and sodium imbalances in PICU patients. Given their significant association with poor outcomes, proactive electrolyte monitoring should be a part of routine critical care protocols. Electrolyte abnormalities, especially potassium disturbances, can serve as a marker of disease severity and guide therapeutic interventions.

Electrolyte disturbances, particularly hyponatremia, hypokalemia, and hypocalcemia, are common in critically ill children. Among these, potassium abnormalities show a significant correlation with mortality, underscoring the prognostic value of serum potassium monitoring in the PICU. Age was not a determining factor for the type or frequency of imbalance, indicating a universal vulnerability across pediatric age groups.

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