Study setting {9}
Paediatric Intensive Care Unit in Queensland Children’s Hospital, Brisbane, Australia.
Eligibility criteria {10}
Eligible children are identified on admission to the mixed PICU (Table 1). Included are neonates, infants and children <16 years of age requiring IVFT within the past 4hours, which must be within the first 24hours of PICU admission. The exclusion criteria are patients who require disease-specific protocols for IVFT, certain pre-existing conditions such as cardiac patients, major electrolyte abnormalities, and futility. Cardiac patients are excluded because of the local practice of using minimal maintenance fluids and using Albumin 4% as the main bolus fluid type in this patient group. Patients with known pre-existing renal disease are not eligible for recruitment as some of the secondary outcomes specifically investigate the impact of the intervention on renal function. This includes patients admitted to PICU post-renal transplantation.
Table 1: Inclusion and exclusion criteria
Group
|
Criterion
|
Definition
|
Inclusion (determined on admission to PICU)
|
|
Age
|
Birth to <16 years of age
|
Location
|
Admitted to PICU
|
Time frame
|
New admission to PICU within the last 24 hours and has received IVFT for ≤4 hours in PICU
|
Decision - Clinician decides that IVFT is required
|
IVFT - All intravenous fluids (boluses and maintenance fluids but not drug dilutions) administered in PICU
|
Biochemistry
|
Admission sodium >130mmol/L (measured on admission or no longer than 48 hours before randomisation)
|
Exclusion
|
|
Age
|
≥16 years
|
Time frame
|
Received IVFT for >4 hours in PICU
|
Pre-existing conditions
|
- Admitted for a cardiac condition
- Chronic kidney disease
|
Disease specific IVFT protocols
|
- Traumatic brain injury or at risk of cerebral edema
- Burns
- Post-liver transplant
- Post-renal transplant
- Diabetic Ketoacidosis
- Oncology patients needing hyperhydration
|
Who will take informed consent? {26a}
Where possible, prospective informed consent will then be sought from parents by the research nurse or doctor. Due to the emergency nature of admissions to PICU, it is anticipated that in certain situations timely informed consent may not be feasible. In these cases, ‘consent to continue’ will be employed. The consent process should be completed by 72 hours after randomisation. If consent is received after 72 hours, this will be recorded as a protocol deviation.
Additional consent provisions for collection and use of participant data and biological specimens {26b}
Not applicable. No other biological specimens will be collected for storage.
Interventions
Explanation for the choice of comparators {6b}
The three arms of the trial are:
- Control arm – 0.9% Sodium Chloride solution (“normal saline”, NS)
- Intervention arm 1 – Plasma-Lyte 148 (PL)
- Intervention arm 2 – Compound Sodium Lactate (CSL)
Intervention description {11a}
From the time of randomisation onwards, the IVFT of the enrolled patient must be provided as per the allocated arm. IVFT includes both maintenance fluids and any potential bolus fluids during the stay in PICU. Total parenteral nutrition will not be considered IVFT. Drug dilutions are not considered IVFT for the study purpose. If a patient was already on another fluid at time of randomisation, the protocol requires the IVFT to change to the allocated fluid. If clinicians decide to provide another study fluid, or another fluid (such as Albumin 4%), the event will be considered a protocol violation and captured as such.
Dose and duration of IVFT: Decisions on indication, dose and duration of IVFT are made by the treating clinician. This ensures a pragmatic approach. The decision to start and stop maintenance and bolus IVFT is also made by the treating clinician.
Other PICU care: An arterial, venous, or capillary blood gas with measurement of pH, sodium and chloride will be performed at the time of randomisation (if no lab results or blood gas are available in the previous 12 hours) and at least every 24 hours thereafter until discharge while the patient is on IVFT and in PICU. All other treatments such as electrolyte supplementation, medications, dextrose infusion, colloid and blood product administration are as per the local institutional procedures. Routine laboratory monitoring of children receiving IVFT such as daily blood tests to assess organ dysfunction are as directed by the clinician.
Criteria for discontinuing or modifying allocated interventions {11b}
Discontinuation of intervention fluid will be at the discretion of the attending clinician. The potential reasons for this might be a new change in clinical status that makes the patient meet one of the exclusion criteria or study closure by the site. Participants’ clinical data as per the case report form, with parent’s permission, will be used for data analysis even after cessation of intervention. If the serum sodium drops to 128mmol/L, the patient will exit the study.
Strategies to improve adherence to interventions {11c}
Clinicians and bedside nurse will have ongoing education to improve adherence to the protocols.
Relevant concomitant care permitted or prohibited during the trial {11d}
Total parenteral nutrition, enteral feeds and fluids, fluid used in drug dilution, fluid used as intravenous flush and blood products (packed red cells, fresh frozen plasma, cryoprecipitate) will not be considered for protocol violations.
Provisions for post-trial care {30}
Patients will exit study on discharge from PICU. There is not further follow-up planned.
Outcomes {12}
The primary outcome is a dichotomous variable defined as an increase in serum chloride ³5mmol/L within 48 hours from the time of randomisation. Secondary clinical outcomes include organ dysfunction free survival, new onset AKI, length of PICU stay, length of hospital stay, and PICU free survival (Table 2). New onset AKI will be additionally calculated using predicted baseline values where a baseline serum creatine value has not been measured [19-21]. Secondary safety outcomes focus on adverse events with respect to electrolyte derangements and are censored at 48 hours from the time of randomisation.
Rationale for the primary outcome
In a retrospective cohort study in 1935 children admitted to a mixed tertiary PICU, Barhight et al observed a 2.3 times increased odds of death (95% confidence interval: 1.03 to 5.21) associated with an increase in chloride level of ³5mmol/L in the first 24 hours after PICU admission [22]. The increase in chloride value was defined as the difference between the admission (first level obtained after PICU admission) and maximum chloride level obtained during the first calender day [22]. Correspondingly, in a post-hoc analysis of the Fluid Expansion of Supportive Therapy Study, Levin et al. demonstrated a 1.65mmol/L (95%-CI 0.47 to 2.83) mean change in serum chloride level in children who received a 10ml/kg bolus of NS or 4% albumin relative to those who did not receive a fluid bolus and this was associated with mortality [23]. Therefore, we have chosen a cutoff of ³5mmol/L increase in chloride level as our primary outcome.
Table 2: Definition of outcome measures
Outcome
|
Criterion
|
Definition
|
Primary
|
Hyperchloremia
|
Increase in serum chloride 5mmol/L
|
- Difference from baseline level to the highest chloride level measured within 48 hours post randomisation
- Baseline level: measured on blood gas at randomisation or using the closest lab or blood gas value up to a maximum of 12 hours before randomisation
- Highest chloride level: obtained in the first 48 hours post randomisation
- Patients will be assumed to have no hyperchloremia if chloride has not been measured in the first 48 hours post randomisation
|
Secondary (clinical)
|
Organ dysfunction free survival
|
Survival free of organ dysfunction
|
- Organ dysfunction defined by Paediatric Logistic Organ Dysfunction 2 Score – PELOD-2) [24]
- A PELOD-2 score of >0 indicates organ dysfunction
- Censored at 28 days post randomisation
- Assume PELOD-2 is zero at discharge from PICU in survivors
- PELOD-2 calculated using the worst values of individual components each day until discharge
- if a certain variable (such as creatinine) was not measured on a given day it is assumed to be normal [24]
|
Acute Kidney Injury (AKI)
|
New onset AKI
|
- AKI defined as per KDIGO 2012 criteria using serum creatinine values [19]
- Includes AKI within the first seven days post randomisation if not present on admission. Serum creatinine values measured in the first 7 days post randomisation will be used to assess AKI as per KDIGO 2012 criteria
- Baseline creatinine: closest serum creatinine value prior to randomization, up to 12 hours before randomisation
- Predicted baseline creatinine: for children <1 year, the reported predicted creatinine values by Boer et al will be used while for children >1 year the below formula will be employed [20].
Mean creatinine (micromol/L) = - 2.37330 - 12.91367 * loge (age) + 23.93581 * (age)1/2 [21]
Presence of AKI on admission:
For those with baseline creatinine –
- Baseline creatinine ≥1.5 times predicted baseline creatinine for those with baseline creatinine
For those without baseline creatinine –
- Patients will be assumed to have no AKI on admission
New onset AKI:
For those with baseline creatinine –
- New onset AKI will be according to KIDIGO 2012 criteria using follow-up creatinine values. If no follow-up creatinine available, these patients would be deemed to have no AKI
For those without baseline creatinine –
- Predicted baseline creatinine value will be calculated and assumed to be the baseline value. This value will be compared to follow-up value (where available) as per KDIGO 2012 criteria. Where no follow-up value is available, these patients would be deemed to have no AKI.
|
Length of stay
|
Length of stay
|
- Length of stay in PICU from randomisation to discharge
- Length of stay in hospital from randomisation to discharge
|
Survival
|
PICU free survival
|
- Censored at 28 days from the post randomisation
- Patients will be assumed to be alive once discharged from PICU
- For patients who die within 28 days, are discharged to a hospice or for palliative care, this value will be recorded as zero
|
Secondary safety outcomes, defined as serum electrolyte/metabolite abnormalities present from randomization to 48 hours post randomisation
|
Adverse event
|
Hyperkalemia
|
- Serum potassium >6.2mmol/L
|
Hypokalemia
|
- Serum potassium <2.5mmol/L
|
Hypercalcemia
|
- Serum corrected total calcium >3.1mmol/L
|
Hypocalcemia
|
- Serum corrected total calcium <1.6mmol/L
|
Hypermagnesemia
|
- Serum magnesium >1.4mmol/L
|
Hyponatremia
|
- Serum sodium <125mmol/L
|
Hyperlactatemia
|
- Arterial or venous blood gas lactate >4mmol/L
|
|
Death in hospital
|
- Number of deaths
|
Legend: PICU - Paediatric Intensive Care Unit, AKI - Acute Kidney Injury, KDIGO – Kidney Disease: Improving Global Outcomes, PELOD-2 - Paediatric Logistic Organ Dysfunction 2 Score
Participant timeline {13}
The duration of the allocated IVFT treatment will extend until day 28 or one of the following, whichever occurs first:
- discharge from PICU, including transfer to another intensive care facility;
- death;
- withdrawal of consent; or
- occurrence of a major adverse event likely related to the intervention.
Enrolment, interventions and assessments are outlined in figure 1.
Sample size {14}
The prevalence of a ³5mmol/L rise in serum chloride level within the first 24hours in children admitted to the PICU has been reported as 12.5% [22]. Based on a review of our institutional PICU data, we expect the proportion of children admitted to PICU requiring IVFT that have a ³5mmol/L rise in chloride level to be approximately 20% by 48 hours. To demonstrate a 10% absolute reduction in prevalence of this primary outcome (setting statistical thresholds of 0.05 for type I error and 80% power), we will need a total of 435 patients. To account for 10% attrition, we will aim to recruit 480 patients. Accounting for ineligible and missed patients, we expect to achieve the recruitment target within an 18-month study period.
Recruitment {15}
An automated extraction of data items required for screening will be undertaken daily from the electronic medical records of all PICU admissions to create a list of all eligible patients. The research nurse will screen this list to determine eligible patients. On weekdays, the research nurse will screen all patients admitted to the PICU each morning. During on-call hours and weekends, the admitting registrar or consultant intensivist will screen for eligibility for recruitment. The reasons for ineligibility and for non-participation of eligible candidates will be documented by the clinical research nurse in the screening log. Co-enrollment with other studies (with different primary outcomes) will be allowed. Where there are repeat admissions to PICU, patients are eligible for re-randomisation if the readmission occurs after 28 days of the previous randomisation.
Assignment of interventions: allocation
Sequence generation {16a}
Online variable block randomisation with block sizes of 3, 6 and 9 and equal 1:1:1 allocation into each of the study interventions NS, PL and CSL will be administered through the online REDCap randomisation tool hosted by the University of Queensland.
Concealment mechanism {16b}
REDCap online randomisation tool will be employed to implement allocation sequence.
Implementation {16c}
Automated generation of the allocation sequence will occur in the REDCap trial database. The bedside nurse or the clinician will enroll patients. REDCap online ramdomisation will assign participants to interventions.
Assignment of interventions: Blinding
Who will be blinded {17a}
Not applicable. This is an open-label trial.
Procedure for unblinding if needed {17b}
Not applicable. There is no blinding as part of interventions in this study.
Data collection and management
Plans for assessment and collection of outcomes {18a}
Data collection will be performed using a combination of manual data entry into a REDCap study database (25, 26) and automated data extraction from the PICU clinical information system (MetaVisionV 5ä, iMDsoft, Tel Aviv) (Appendix 1). Structured query language (SQL) will be used to automate the extraction of the relevant, routinely collected clinical data values from MetaVisionTM. Information on demographics, severity on admission, diagnostic codes, interventions, and length of stay will be extracted through the mandatory data fields which the institution provides to the Australian and New Zealand Paediatric Intensive Care Registry(27). Further detail data collection methods are included in appendix 1 as part of the statistical analysis plan.
Plans to promote participant retention and complete follow-up {18b}
Participants will remain in the study until discharge from PICU. Data on protocol violations, eligibility and recruitment rate will be reported. Fluids that are considered as part of the intervention are: any fluid bolus and any IV maintenance. Total parenteral nutrition, enteral feeds and fluids, fluid used in drug dilution, fluid used as intravenous flush and blood products (packed red cells, fresh frozen plasma, cryoprecipitate) will not be considered for protocol violations. Use of 4% and 20% albumin will be considered a protocol violation.
Data management {19}
Manual primary source verification will be performed in 100% of cases for the inclusion criteria and the primary outcome through independent monitoring staff. Extracted data values for random selected 5% of the study cohort will be manually assessed against the user-interface of MetaVisionTM.
Confidentiality {27}
Participant confidentiality will be strictly held in trust by the participating investigators, research staff, and the sponsoring institution and their agents. The study protocol, documentation, data and all other information generated will be held in strict confidence. Any data, forms, reports and other records that leave the site will be identified only by a participant identification number (Participant ID, PID) to maintain confidentiality. All records will be stored in a secure online trial database. All computer entry and networking programs will be done using PIDs only. No information concerning the study, or the data will be released to any unauthorized third party, without prior written approval of the sponsoring institution. Clinical information will not be released without written permission of the participant, except as necessary for monitoring by human research ethics committee or regulatory agencies.
Plans for collection, laboratory evaluation and storage of biological specimens for genetic or molecular analysis in this trial/future use {33}
Not applicable. No biological samples will be collected for genetic or molecular analysis as part of this trial.
Statistical methods
Statistical methods for primary and secondary outcomes {20a}
A per-protocol (PP) analysis will also be undertaken for the primary outcome only including all children who were eligible, randomised, where consent is available, who received the allocated fluid and where both baseline and follow-up chloride measures were obtained.
Interim analyses {21b}
A formal interim analysis will be performed after recruitment of 176 children. There are no predetermined stopping rules for this trial.
Methods for additional analyses (e.g. subgroup analyses) {20b}
We will repeat the ITT and PP analyses for the following subgroups for the primary outome:
- Age at PICU admission: £6 months, >6 months to 5 years, >5 years to <16 years
- Admission type: elective versus non-elective admissions
- Patients who received IV fluids for: >24 hours, ≤24 hours
- Patients who received: >50ml/kg IVFT in the first 48 hours since randomisation, ≤50ml/kg IVFT in the first 48 hours since randomisation
The age subgroup was chosen to delineate the effect of IVFT on neonates and small infants, young children and adolescents. Children who are non-electively admitted to PICU may be sicker and hence, might receive IVFT for longer. Furthermore, they might have more marked metabolic derangement and respond to IVFT differently to fewer sick patients. Hence, we will be analysing the primary outcome in this subgroup separately. As we hypothesise that the increase in chloride level will be proportional to the amount of intravenous fluid received, we will look at specific sub-group of patients who received IVFT for >24 hours and those who received >50ml/kg (empirical cutoff) in the first 48 hours since randomisation.
Methods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c}
The proportion of patients who received the allocated fluid will be reported, and the proportion of contamination in ml/kg per day for the first 48hours, and ml/kg for the entire admission will be reported. Additionally, the number of patients who had baseline chloride and repeat chloride level measured, number of patients who were administered IVFT for >24 hours and who received >50ml/kg (empirical cutoff) in the first 48 hours since randomisation will be reported in total and for each arm. A detailed statistical analysis plan is included in appendix 1.
Plans to give access to the full protocol, participant level-data and statistical code {31c}
The authors can provide the full protocol. The statistical analysis plan is attached as appendix. The statistical code is also available at https://github.com/kgibbons44/SPLYTPAnalysis/.
Oversight and monitoring
Composition of the coordinating centre and trial steering committee {5d}
SR, AS, LS, MK and KG comprise the steering committee.
Composition of the data monitoring committee, its role and reporting structure {21a}
While there is not data safety monitoring board for this study, the trial will be overseen by a Trial Steering Committee (TSC), the membership of which will include: the PI, 2 further PIs, senior epidemiologist/statistician and a senior research nurse. The role of the TSC will be to monitor and supervise progress of the trial and review at regular intervals relevant information from other sources.
Adverse event reporting and harms {22}
Commonly expected complications related to the underlying disease will not be reported as an adverse event. This may be organ dysfunction such as cardiac or respiratory failure, need for inotropic support or death. Renal dysfunction will be noted separately, as this would be one of the secondary outcomes.
Potential intervention specific adverse events might be hyperkalemia, hypokalemia, hypercalcemia, hypocalcemia, hypermagnesemia, hyponatremia, hyperlactatemia and death in hospital.
Laboratory biochemistry values will be reviewed every day by the attending clinician and where concerns of an AE exist, this will be discussed with the PI and documented by the clinical research nurse. As these events may be due to the fact that the patient is sick, the attending clinician will be requested to state if in their personal opinion the event potentially could be related to the intervention.
For the purposes of this study the site investigator is responsible for recording all AEs, regardless of their relationship to study intervention, for the period from randomisation until discharge from hospital. Conditions that are present at screening and do not deteriorate will not be considered AEs. AEs will be reported to the PI as soon as possible. The PI along with the rest of the research team will review all AEs and determine relatedness and severity. Complications and side effects will be reported using the existing hospital internal reporting structures and databases. The PI will then report back to the patients where appropriate and the ethics committee.
Frequency and plans for auditing trial conduct {23}
While ongoing regular trial conduct and data monitoring is in place, specific timepoints, frequency and procedures for formal audits are not planned.
Plans for communicating important protocol amendments to relevant parties (e.g. trial participants, ethical committees) {25}
All protocol amendments will be approved by the HREC. The ANZPICR application will also be amended accordingly to mirror these changes.
Dissemination plans {31a}
Given the lead role of the investigators in paediatric intensive care; their role in regional and state-wide guideline development processes; their involvement in professional colleges and at key educational conferences it is likely that the findings will have nationwide impact across Australia and New Zealand.
Publication in high impact peer-reviewed journals will be sought and presentation at national and international conferences is anticipated. Novel and modern information dissemination strategies will also be used including social media, podcast presentations and Free Open Access Medical education (FOAM) resources to generate discussion and disseminate the outcomes of the study.