Pneumonia, wheezing and asthma were more common in children after thymectomy due to open-heart surgery.

AIM: This nationwide study evaluated the clinical impact that an early thymectomy, during congenital heart defect (CHD) surgery, had on the health of children and adolescents. METHODS: The subjects were patients aged 1-15 years who had undergone CHD surgery at the University Children's Hospital, Helsinki, where all CHD surgery in Finland is carried out, from 2006 to 2018. The parents or the cases and population-based controls, matched for sex, age and hospital district, completed electronic questionnaires. We excluded those with low birth weights or a known immunodeficiency. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were calculated for prespecified outcomes. RESULTS: We received responses relating to 260/450 (58%) cases and 1403/4500 (31%) controls and excluded 73 cases with persistent cardiac or respiratory complaints after surgery. The CHD group reported more recurrent hospitalisations due to infections (aOR 6.3, 95% CI 3.0-13) than the controls and more pneumonia episodes (aOR 3.5, 95% CI 2.1-5.6), asthma (aOR 2.5, 95% CI 1.5-4.1) and wheezing (aOR 2.1, 95% CI 1.5-2.9). CONCLUSION: Hospitalisation due to infections, pneumonia, wheezing and asthma was more common in children after a thymectomy due to open-heart surgery than population-based controls, underlining the importance of immunological follow-ups.

Adverse cardiovascular events are common during dexmedetomidine administration in neonates and infants during intensive care.

AIM: This study aimed to assess the safety of a commonly used sedative, dexmedetomidine in neonates and infants during intensive care. METHODS: A retrospective cohort study was conducted in the paediatric intensive care unit at Oulu University Hospital. The study population consisted of all children from birth up to 6 months of age who received dexmedetomidine during 2010-2016. Adverse cardiovascular outcomes were defined as abnormal heart rates or blood pressure values according to the Paediatric Early Warning Score. RESULTS: Of the 172 infants, 56% had congenital malformation, and 48% had undergone surgery. Neonates and 1-3-month-olds experienced bradycardia (86% vs. 73% in 1-3-month-olds and 50% in 3-6-month-olds, p = 0.001) and severe bradycardia (17% vs. 14% in 1-3-month-olds and 0% in 3-6-month-olds, p = 0.005) more often than older patients. The median maximum rate of dexmedetomidine infusion was 0.86 µg/kg/h (IQR = 0.60-1.71 µg/kg/h). A dose-dependent increase in bradycardia and severe hypotension was found. Adverse cardiovascular events were managed with additional fluid boluses and discontinuation of the infusion. CONCLUSION: Adverse cardiovascular events were common during dexmedetomidine administration in neonates and infants. Lower dexmedetomidine doses may be required in sedating neonates.

Severe hospital-acquired hyponatremia in acutely ill children receiving moderately hypotonic fluids.

BACKGROUND: Hypotonic fluids have been associated with hospital-acquired hyponatremia. The incidence of life-threatening severe hyponatremia associated with hypotonic fluids has not been evaluated. METHODS: This was a population-based cohort study of 46,518 acutely ill children 15 years of age or under who visited the pediatric emergency department (ED) at Oulu University Hospital, Finland, between 2007 and 2017. We retrieved all electrolyte measurements from the comprehensive electronic laboratory system and reviewed medical records for all patients with severe hyponatremia. RESULTS: The overall occurrence of severe hyponatremia (serum sodium < 125 mmol/L) was found in 27 out of 46,518 acutely ill children (0.06%, 95% confidence interval 0.04-0.08%). After admission, severe hyponatremia developed in seven of 6,984 children receiving moderately hypotonic fluid therapy (0.1%, 95% confidence interval 0.04-0.2%), usually within 8 h of admission. All children who developed severe hyponatremia during hospitalization were severely ill. CONCLUSION: In this register-based cohort study of children presenting to the ED, severe hyponatremia developed in one of 998 acutely ill children receiving moderately hypotonic fluid therapy. A higher resolution version of the Graphical abstract is available as Supplementary information.

National survey revealed variable practices in paediatric procedural sedation and patient monitoring.

Paediatric procedures requiring sedation are increasingly being performed off site, but there are no national guidelines for paediatric procedural sedation in Finland or studies on it. Therefore, the aim of this survey was to assess national practices for paediatric procedural sedation outside operation rooms and intensive care units in terms of indications, sedative medication, treatment facilities, patient safety and training of the personnel. An online survey including single- and multiple-choice questions and open-ended questions was sent to Finnish paediatricians, paediatric surgeons and paediatric anaesthesiologists via the electronic mailing lists of national societies in December 2019. A total of 71 responses were received. Lumbar puncture (41%), intra-articular injections (38%) and MRI (17%) were the most common procedures that required routine sedation. Benzodiazepines were the most frequently used sedatives during both painful procedures (80%) and imaging (61%). Pulse oximetry monitoring was reported by 75% of the respondents, but other physiological parameters were rarely monitored (ECG 28%; blood pressure 39%; respiratory rate 34%). The level of sedation was not objectively assessed. Adrenaline (72%) and equipment for managing adverse respiratory outcomes (supplemental oxygen 98%; ventilation equipment 92%) were available in most facilities in which sedation was performed. Only one-third of the respondents had undergone training for paediatric procedural sedation, and only 39% of the hospital units compiled statistical data on sedation-related adverse events. The paediatric procedural sedation practices vary across hospitals. National guidelines for patient monitoring and training of personnel could improve treatment quality and patient safety.

Systematic review and meta-analysis found that intranasal dexmedetomidine was a safe and effective sedative drug during paediatric procedural sedation.

AIM: This systematic review and meta-analysis evaluated the effectiveness of intranasal dexmedetomidine as a sole sedative during paediatric procedural sedation outside the operating room. METHODS: Relevant literature identified by PubMed, Scopus, ClinicalTrials.gov, ScienceDirect and Cochrane Library up to 31 December 2019 was systematically reviewed. Randomised controlled trials that compared intranasal dexmedetomidine with another sedative or placebo during paediatric procedural sedation were included. Trials that studied intranasal dexmedetomidine as a premedication before anaesthesia were excluded. The primary outcome was the success of the planned procedure. RESULTS: We analysed seven randomised controlled trials of 730 patients: four trials with 570 patients compared dexmedetomidine with chloral hydrate and three trials with 160 patients compared dexmedetomidine with midazolam. The incidence of successfully completing the procedure did not differ between dexmedetomidine and chloral hydrate, but dexmedetomidine had a higher success rate than midazolam. The incidence of hypotension, bradycardia or respiratory complications did not differ between the sedatives used. Nausea and vomiting were more common in children treated with chloral hydrate than in those treated with other sedatives. CONCLUSION: Intranasal dexmedetomidine was a safe and effective sedative for minor paediatric procedures.

Intravenous magnesium sulfate for acute wheezing in young children: a randomised double-blind trial.

Magnesium sulfate has been shown to be an effective treatment in older children with asthma exacerbations, but it has not been investigated in acute severe virus-induced wheezing in young children.The study enrolled 61 children aged 6 months to 4 years. Inclusion criteria were severe wheezing, classified as a score of ≥6 points as assessed by the Respiratory Distress Assessment Instrument (RDAI) after initial treatment with salbutamol, and the symptoms of acute viral infection. The children were randomly allocated to receive either an infusion of magnesium sulfate (40 mg·kg-1) or 0.9% sodium chloride as a placebo infusion for 20 min. Primary outcome measure was mean change in RDAI scores from baseline to 6 h after the treatment.Change in the severity of wheezing from baseline to 6 h after the treatment, as measured by mean±sd RDAI scores, was 4.7±2.6 in the magnesium sulfate group and 4.2±4.2 in the placebo group (difference 0.5, 95% CI -1.3 to 2.3, p=0.594).Intravenous magnesium sulfate was ineffective in treating acute severe virus-induced wheezing in young children, in contrast to the previous efficacy demonstrated in older children.

Congenital aortic stenosis: treatment outcomes in a nationwide survey.

OBJECTIVE: To evaluate treatment outcomes of pediatric valvar aortic stenosis (AS) in a nationwide follow-up. DESIGN: Balloon aortic valvuloplasty (BAV) has been the preferred treatment for congenital AS in Finland since the year 2000. All children treated due to isolated AS during 2000-2014 were included in this retrospective study. Treatment outcomes were categorized into Optimal: residual gradient ≤35 mmHg and trivial or no aortic regurgitation (AR), Adequate: gradient ≤35 mmHg with mild AR, or Inadequate: gradient >35 mmHg and/or moderate to severe AR. RESULTS: Sixty-one patients underwent either BAV (n = 54) or surgical valvuloplasty (n = 7) for valvar AS at a median age of 29 days (range 6 hours to 16.9 years). The proportion of patients not requiring reintervention at 1, 5, and 10 years was 61%, 50%, and 29% in neonates and 83%, 73%, and 44% in older patients, respectively (p = .02); without difference between treatment groups. Larger proportion of patients remained free from valve surgery after optimal BAV result than after adequate or inadequate result (p = .01). The reason for the first reintervention was AS in 50%, AR in 36%, and combined aortic valve disease in 16% of cases. Early mortality (before hospital discharge) was 4.9%, and associated with critical AS in neonates. There was no late mortality during the follow-up. CONCLUSIONS: Although majority of congenital AS patients require more than one intervention during childhood, an optimal BAV result improves long-term outcome by increasing the proportion of patients remaining free from valve surgery. High long-term freedom from reintervention is attainable also in the neonatal population.

Neurally adjusted ventilatory assist (NAVA) in preterm newborn infants with respiratory distress syndrome-a randomized controlled trial.

UNLABELLED: Neurally adjusted ventilatory assist (NAVA) improves patient-ventilator synchrony during invasive ventilation and leads to lower peak inspiratory pressures (PIP) and oxygen requirements. The aim of this trial was to compare NAVA with current standard ventilation in preterm infants in terms of the duration of invasive ventilation. Sixty infants born between 28 + 0 and 36 + 6 weeks of gestation and requiring invasive ventilation due to neonatal respiratory distress syndrome (RDS) were randomized to conventional ventilation or NAVA. The median durations of invasive ventilation were 34.7 h (quartiles 22.8-67.9 h) and 25.8 h (15.6-52.1 h) in the NAVA and control groups, respectively (P = 0.21). Lower PIPs were achieved with NAVA (P = 0.02), and the rapid reduction in PIP after changing the ventilation mode to NAVA made following the predetermined extubation criteria challenging. The other ventilatory and vital parameters did not differ between the groups. Frequent apneas and persistent pulmonary hypertension were conditions that limited the use of NAVA in 17 % of the patients randomized to the NAVA group. Similar cumulative doses of opiates were used in both groups (P = 0.71). CONCLUSIONS: NAVA was a safe and feasible ventilation mode for the majority of preterm infants suffering from RDS, but the traditional extubation criteria were not clinically applicable during NAVA. WHAT IS KNOWN: • NAVA improves patient-ventilator synchrony during invasive ventilation. • Lower airway pressures and oxygen requirements are achieved with NAVA during invasive ventilation in preterm infants by comparison with conventional ventilation. What is new: • Infants suffering from PPHN did not tolerate NAVA in the acute phase of their illness. • The traditional extubation criteria relying on inspiratory pressures and spontaneous breathing efforts were not clinically applicable during NAVA.

Reference Values for Echocardiography in Middle-Aged Population: The Cardiovascular Risk in Young Finns Study.

BACKGROUND: Population and sex-specific reference limits produced with modern ultrasound equipment are needed for accurate clinical echocardiography diagnostics. We report a comprehensive set of reference limits of cardiac function and dimensions in a group of young and middle-aged Finnish men and women produced by the recommendations of European Society of Echocardiography and American Society of Cardiology. METHODS AND RESULTS: Cardiac structure and function was studied in a standardized comprehensive echocardiographic examination in 1,079 healthy volunteers without cardiovascular diseases or major known risk factors participating in the population-based Young Finns study (444 men and 635 women, age range 34 and 49 years). We present sex-specific reference values for echocardiographic parameters reflecting cardiac structure (ventricular and atrial dimensions and volumes, left ventricular wall thickness and mass, aortic root) and function. From the 86 measured parameters, only 7 were not statistically significantly different between sexes. CONCLUSION: The Young Finns study provides echocardiographic reference ranges for cardiac structure and function quantification that can be utilized to enhance the accuracy or echocardiography diagnostics. The results emphasize the need for sex-specific assessment for most echocardiographic parameters.

Effect of body position on ventilation distribution in healthy newborn infants: an observational study.

OBJECTIVES: Newborn infants have unique respiratory physiology compared with older children and adults due to their lungs' structural and functional immaturity and highly compliant chest wall. To date, ventilation distribution has seldom been studied in this age group. This study aims to assess the effect of body position on ventilation distribution in spontaneously breathing healthy neonates. DESIGN: Prospective observational study. SETTING: Maternity wards of Oulu University Hospital. PATIENTS: 20 healthy, spontaneously breathing, newborn infants. INTERVENTIONS: Electrical impedance tomography data were recorded with a 32-electrode belt (Sentec AG, Landquart, Switzerland) in six different body positions in random order. Ventilation distribution was retrospectively assessed 10 minutes after each position change. MAIN OUTCOME MEASURES: In each position, regional tidal impedance variation (ΔZ) and ventral-to-dorsal and right-to-left centre of ventilation were measured. RESULTS: The mean global ΔZ was the largest in supine position and it was smaller in prone and lateral positions. Yet, global ΔZ did not differ in supine positions, ventilation distribution was more directed towards the non-dependent lung region in supine tilted position (p<0.001). In prone, a reduction of global ΔZ was observed (p<0.05) corresponding to an amount of 10% of global tidal variation in supine position. In both lateral positions, tidal ventilation was distributed more to the corresponding non-dependent lung region. CONCLUSIONS: Prone or lateral body positioning in healthy spontaneously breathing newborns leads to a redistribution of ventilation to the non-dependent lung regions and at the same time global tidal volume is reduced as compared with supine.

Effects of antibiotics, hospitalisation and surgical complications on self-reported immunological vulnerability following paediatric open-heart surgery and thymectomy: a single-centre retrospective cohort study.

BACKGROUND: Partial or complete thymectomy is routinely performed in paediatric open-heart surgeries when treating congenital heart defects. Whether or not thymectomised children require systematic immunological monitoring later in life is unknown. The objective of this study was to investigate the effects of preoperatively and postoperatively used antibiotics, hospitalisation and surgical complications on self-reported immunological vulnerability in paediatric patients with early thymectomy to better recognise the patients who could benefit from immunological follow-up in the future. METHODS: We conducted a retrospective cohort study, including 98 children and adolescents aged 1-15 years, who had undergone an open-heart surgery and thymectomy in infancy and who had previously answered a survey regarding different immune-mediated symptoms and diagnoses. We performed a comprehensive chart review of preoperative and postoperative factors from 1 year preceding and 1 year following the open-heart surgery and compared the participants who had self-reported symptoms of immunological vulnerability to those who had not. RESULTS: The median age at primary open-heart surgery and thymectomy was 19.5 days in the overall study population (60% men, n=56) and thymectomies mainly partial (80%, n=78). Broad-spectrum antibiotics were more frequently used preoperatively in participants with self-reported immunological vulnerability (OR=3.05; 95% CI 1.01 to 9.23). This group also had greater overall use of antibiotics postoperatively (OR=3.21; 95% CI 1.33 to 7.76). These findings were more pronounced in the subgroup of neonatally operated children. There was no statistically significant difference in the duration of intensive care unit stay, hospitalisation time, prevalence of severe infections, surgical complications or glucocorticoid use between the main study groups. CONCLUSION: Antimicrobial agents were more frequently used both preoperatively and postoperatively in thymectomised children with self-reported immunological vulnerability after thymectomy. Substantial use of antimicrobial agents early in life should be considered a potential risk factor for increased immunological vulnerability when evaluating the significance of immune-mediated symptom occurrence in thymectomised paediatric patients.

Effect of routine suction on lung aeration in critically ill neonates and young infants measured with electrical impedance tomography.

Endotracheal suctioning is a widely used procedure to remove secretions from the airways of ventilated patients. Despite its prevalence, regional effects of this maneuver have seldom been studied. In this study, we explore its effects on regional lung aeration in neonates and young infants using electrical impedance tomography (EIT) as part of the large EU-funded multicenter observational study CRADL. 200 neonates and young infants in intensive care units were monitored with EIT for up to 72 h. EIT parameters were calculated to detect changes in ventilation distribution, ventilation inhomogeneity and ventilation quantity on a breath-by-breath level 5-10 min before and after suctioning. The intratidal change in aeration over time was investigated by means of regional expiratory time constants calculated from all respiratory cycles using an innovative procedure and visualized by 2D maps of the thoracic cross-section. 344 tracheal suctioning events from 51 patients could be analyzed. They showed no or very small changes of EIT parameters, with a dorsal shift of the center of ventilation by 0.5% of the chest diameter and a 7% decrease of tidal impedance variation after suctioning. Regional time constants did not change significantly. Routine suctioning led to EIT-detectable but merely small changes of the ventilation distribution in this study population. While still a measure requiring further study, the time constant maps may help clinicians interpret ventilation mechanics in specific cases.

Generation of Anatomically Inspired Human Airway Tree Using Electrical Impedance Tomography: A Method to Estimate Regional Lung Filling Characteristics.

The purpose of lung recruitment is to improve and optimize the air exchange flow in the lungs by adjusting the respiratory settings during mechanical ventilation. Electrical impedance tomography (EIT) is a monitoring tool that permits measurement of regional pulmonary filling characteristics or filling index (FI) during ventilation. The conventional EIT system has limitations which compromise the accuracy of the FI. This paper proposes a novel and automated methodology for accurate FI estimation based on EIT images of recruitable regional collapse and hyperdistension during incremental positive end-expiratory pressure. It identifies details of the airway tree (AT) to generate a correction factor to the FIs providing an accurate measurement. Multi-scale image enhancement followed by identification of the AT skeleton with a robust and self-exploratory tracing algorithm is used to automatically estimate the FI. AT tracing was validated using phantom data on a ground-truth lung. Based on generated phantom EIT images, including an established reference, the proposed method results in more accurate FI estimation of 65% in all quadrants compared with the current state-of-the-art. Measured regional filling characteristics were also examined by comparing regional and global impedance variations in clinically recorded data from ten different subjects. Clinical tests on filling characteristics based on extraction of the AT from the resolution enhanced EIT images indicated a more accurate result compared with the standard EIT images.

Bronchodilator effect on regional lung function in pediatric viral lower respiratory tract infections.

Objective.Viral lower respiratory tract infections (LRTI) are the leading cause for acute admission to the intensive care unit in infants and young children. Nebulized bronchodilators are often used when treating the most severe cases. The aim of this study was to investigate the bronchodilator effect on respiratory mechanics during intensive care with electrical impedance tomography (EIT) and to assess the feasibility of EIT in this context.Approach.We continuously monitored the children with chest EIT for up to 72 h in an observational study design. The treatment decisions were done by clinical assessment, as the clinicians were blinded to the EIT information during data collection. In a retrospective analysis, clinical parameters and regional expiratory time constants determined by EIT were used to assess the effects of bronchodilator administration, especially regarding airway resistance.Main results.We included six children from 11 to 27 months of age requiring intensive care due to viral LRTI and receiving bronchodilator agents. Altogether 131 bronchodilator administrations were identified during EIT monitoring. After validation of the exact timing of events and EIT data quality, 77 administrations were included in the final analysis. Fifty-five bronchodilator events occurred during invasive ventilation and 22 during high-flow nasal cannulae treatment. Only 17% of the bronchodilator administrations resulted in a relevant decrease in calculated expiratory time constants.Significance.Continuous monitoring with EIT might help to optimize the treatment of LRTI in pediatric intensive care units. In particular, EIT-based regional expiratory time constants would allow objective assessment of the effects of bronchodilators and other respiratory therapies.

Cross-sectional chest circumference and shape development in infants.

OBJECTIVE: This study investigates the development of the thoracic cross-section at the nipple line level during the early stages of life. Unlike the descriptive awareness regarding chest development course, there exist no quantitative references concerning shape, circumference and possible dependencies to age, gender or body weight. The proposed mathematical relations are expected to help create guidelines for more realistic modelling and potential detection of abnormalities. One potential application is lung electrical impedance tomography (EIT) monitoring where accurate chest models are crucial in both extracting reliable parameters for regional ventilation function and design of EIT belts. Despite their importance, such reference data is not readily available for the younger age range due to insufficient data amid the regulations of neonatal imaging. RESULTS: Chest circumference shows the highest correlation to body weight following the relation [Formula: see text] where x is the body weight in grams and f(x) is the chest circumference in cm at the nipple line level. No statistically significant difference in chest circumference between genders was detected. However, the shape indicated signs of both age and gender dependencies with on average boys developing a more rectangular shape than girls from the age of 1 years and 9 months.

Prolonged Continuous Monitoring of Regional Lung Function in Infants with Respiratory Failure.

Rationale: Electrical impedance tomography (EIT) allows instantaneous and continuous visualization of regional ventilation and changes in end-expiratory lung volume at the bedside. There is particular interest in using EIT for monitoring in critically ill neonates and young children with respiratory failure. Previous studies have focused only on short-term monitoring in small populations. The feasibility and safety of prolonged monitoring with EIT in neonates and young children have not been demonstrated yet. Objectives: To evaluate the feasibility and safety of long-term EIT monitoring in a routine clinical setting and to describe changes in ventilation distribution and homogeneity over time and with positioning in a multicenter cohort of neonates and young children with respiratory failure. Methods: At four European University hospitals, we conducted an observational study (NCT02962505) on 200 patients with postmenstrual ages (PMA) between 25 weeks and 36 months, at risk for or suffering from respiratory failure. Continuous EIT data were obtained using a novel textile 32-electrode interface and recorded at 48 images/s for up to 72 hours. Clinicians were blinded to EIT images during the recording. EIT parameters and the effects of body position on ventilation distribution were analyzed offline. Results: The average duration of EIT measurements was 53 ± 20 hours. Skin contact impedance was sufficient to allow image reconstruction for valid ventilation analysis during a median of 92% (interquartile range, 77-98%) of examination time. EIT examinations were well tolerated, with minor skin irritations (temporary redness or imprint) occurring in 10% of patients and no moderate or severe adverse events. Higher ventilation amplitude was found in the dorsal and right lung areas when compared with the ventral and left regions, respectively. Prone positioning resulted in an increase in the ventilation-related EIT signal in the dorsal hemithorax, indicating increased ventilation of the dorsal lung areas. Lateral positioning led to a redistribution of ventilation toward the dependent lung in preterm infants and to the nondependent lung in patients with PMA > 37 weeks. Conclusions: EIT allows continuous long-term monitoring of regional lung function in neonates and young children for up to 72 hours with minimal adverse effects. Our study confirmed the presence of posture-dependent changes in ventilation distribution and their dependency on PMA in a large patient cohort. Clinical trial registered with www.clinicaltrials.gov (NCT02962505).

Thoracic shape changes in newborns due to their position.

The highly compliant nature of the neonatal chest wall is known to clinicians. However, its morphological changes have never been characterized and are especially important for a customised monitoring of respiratory diseases. Here, we show that a device applied on newborns can trace their chest boundary without the use of radiation. Such technology, which is easy to sanitise between patients, works like a smart measurement tape drawing also a digital cross section of the chest. We also show that in neonates the supine position generates a significantly different cross section compared to the lateral ones. Lastly, an unprecedented comparison between a premature neonate and a child is reported.

Risk of Electrolyte Disorders in Acutely Ill Children Receiving Commercially Available Plasmalike Isotonic Fluids: A Randomized Clinical Trial.

Importance: The use of isotonic fluid therapy is currently recommended in children, but there is limited evidence of optimal fluid therapy in acutely ill children. Objective: To evaluate the risk for electrolyte disorders, including hyponatremia, hypernatremia, and hypokalemia, and the risk of fluid retention in acutely ill children receiving commercially available plasmalike isotonic fluid therapy. Design, Setting, and Participants: This unblinded, randomized clinical pragmatic trial was conducted at the pediatric emergency department of Oulu University Hospital, Finland, from October 3, 2016, through April 15, 2019. Eligible study subjects (N = 614) were between 6 months and 12 years of age, required hospitalization due to an acute illness, and needed intravenous fluid therapy. Exclusion criteria included a plasma sodium concentration of less than 130 mmol/L or greater than 150 mmol/L on admission; a plasma potassium concentration of less than 3.0 mmol/L on admission; clinical need of fluid therapy with 10% glucose solution; a history of diabetes, diabetic ketoacidosis, or diabetes insipidus; a need for renal replacement therapy; severe liver disease; pediatric cancer requiring protocol-determined chemotherapy hydration; and inborn errors of metabolism. All outcomes and samples size were prespecified except those clearly marked as exploratory post hoc analyses. All analyses were intention to treat. Interventions: Acutely ill children were randomized to receive commercially available plasmalike isotonic fluid therapy (140 mmol/L of sodium and 5 mmol/L potassium in 5% dextrose) or moderately hypotonic fluid therapy (80 mmol/L sodium and 20 mmol/L potassium in 5% dextrose). Main Outcomes and Measures: The primary outcome was the proportion of children with any clinically significant electrolyte disorder, defined as hypokalemia less than 3.5 mmol/L, hypernatremia greater than 148 mmol/L, or hyponatremia less than 132 mmol/L during hospitalization due to acute illness. The main secondary outcomes were the proportion of children with severe hypokalemia and weight change. Results: There were 614 total study subjects (mean [SD] age, 4.0 [3.1] years; 315 children were boys [51%] and all 614 were Finnish speaking [100%]). Clinically significant electrolyte disorder was more common in children receiving plasmalike isotonic fluid therapy (61 of 308 patients [20%]) compared with those receiving moderately hypotonic fluid therapy (9 of 306 patients [2.9%]; 95% CI of the difference, 12%-22%; P < .001). The risk of developing electrolyte disorder was 6.7-fold greater in children receiving isotonic fluid therapy. Hypokalemia developed in 57 patients (19%) and hypernatremia developed in 4 patients (1.3%) receiving plasmalike isotonic fluid therapy. Weight change was greater in children receiving isotonic, plasmalike fluid therapy compared with those receiving mildly hypotonic fluids (mean weight gain, 279 vs 195 g; 95% CI, 16-154 g; P = .02). Conclusions and Relevance: In this randomized clinical trial, commercially available plasmalike isotonic fluid therapy markedly increased the risk for clinically significant electrolyte disorders, mostly due to hypokalemia, in acutely ill children compared with previously widely used moderately hypotonic fluid therapy containing 20 mmol/L of potassium. Trial Registration: ClinicalTrials.gov identifier: NCT02926989.