L-citrulline for Prevention of Sequelae of Acute Lung Injury in Pediatrics Undergoing Cardiopulmonary Bypass for Heart Defects

Mechanical ventilation (MV) = invasive or noninvasive MV incl. bilevel (biphasic) positive airway pressure or continuous positive airway pressure. Inotrope use = medications considered within the derivation of total inotrope score (dopamine, dobutamine, milrinone, epinephrine, phenylephrine, norepinephrine). Both measures recorded until earliest of subject hospital discharge or Day 28.

The same definitions and analyses as described for the primary endpoint will be applied.

The same definitions and analyses as described for the primary endpoint will be applied.

The same definitions and analyses as described for the primary endpoint will be applied.

Inotrope score is reflective of the pharmacological support required by the cardiovascular system and is a good predictor of mortality and morbidity in patients undergoing bypass surgery. A lower inotrope score represents less pharmacological support and would indicate a lower risk for a poor clinical outcome. Therefore, any treatment effect would be indicated by a lower inotrope score in the citrulline group when compared to the placebo group.

In this study, the score was calculated each hour post-operatively from the time of separation from bypass until the completion of study drug. Additionally, the total inotrope score over time until Day 28 or hospital discharge was derived. Inotrope score was calculated using the following formula:

Total inotrope score = Dopamine dose (µg/kg/min) + Dobutamine dose (µg/kg/min) + 10 * Milrinone dose (µg/kg/min) + 100 * Epinephrine dose (µg/kg/min) + 100 * Phenylephrine dose (µg/kg/min) + 100 * Norepinephrine dose (µg/kg/min).

Heart rate at hours 1, 2, 4, 12, 24 and 48.

Systemic arterial blood pressure at hours 1, 2, 4, 12, 24 and 48.

Oxygen saturation at hours 1, 2, 4, 12, 24 and 48.

Central venous pressure at hours 1, 2, 4, 12, 24 and 48.

The thoracotomy output is defined as the total volume of chest tube drainage recorded in cc prior to discontinuation of chest intubation. The total postoperative duration (in hours) that the chest tube is used will be calculated as the time from the end of the surgery to the time the chest tube is removed. If an additional chest tube is required or reinserted (until discharge from the hospital or at Day 28) the duration that the additional chest tube was used (from time of insertion to time of removal) will be added to the time the original chest tube was used for the total postoperative duration. If a subject did not use any chest tube the duration is set to 0. As a sensitivity analysis, subjects with no use of chest tube will be excluded. For subjects who died before discharge from the hospital or before Day 28, respectively, the observed duration of chest tube drainage will be used.

The length will be derived as the time in hours from separation from CPB until discontinuation of intubation. Any duration of re-use of intubation will continue to accrue. If a subject did not use any intubation the length is set to 0. As a sensitivity analysis, subjects with no use of intubations will be excluded. For subjects who died before discharge from the hospital or before Day 28, respectively, the observed length of time on intubation will be used. As sensitivity analyses subjects who died will (1) be excluded from analysis and (2) be assigned a length of time on intubation of 28 days.

For the length of time on intubation the same analyses as described for the primary endpoint will be applied.

The length of PICU stay will be calculated as the total number of days postoperative until discharge from PICU. For subjects who died before discharge from PICU or before Day 28, respectively, the observed length of PICU stay will be used. As sensitivity analyses subjects who died will (1) be excluded from analysis and (2) be assigned a length of PICU stay of 28 days. For the length of PICU stay the same analyses as described for the primary endpoint will be applied.

Length of time on vasodilators will be measured from first use following separation from bypass, until the subject is discharged from the hospital or at Day 28. The length will be derived as the time in hours from separation from CPB until discontinuation of all vasodilators.

The length of hospitalization will be calculated as the total number of days postoperative until discharge from the hospital. For subjects who died before discharge from the hospital or before Day 28, respectively, the observed length of hospitalization will be used. As sensitivity analyses subjects who died will (1) be excluded from analysis and (2) be assigned a length of hospitalization of 28 days. The same analyses as described for the primary endpoint will be applied.

Plasma citrulline concentrations will be assessed in both treatment groups to determine the number of patients who reach the therapeutic sustained target plasma citrulline level of ≥100 μmol/L. Blood collection for assessment of plasma citrulline concentrations will be taken prior to surgery, during surgery, 30 minutes post-decannulation after CPB (prior to bolus and 5 minutes after bolus), at the specified post-operative time points (6h, 12h, 24h, 48h), and at hospital discharge or Day 28, whichever occurs first.

Pre-treatment adverse events and treatment adverse events will be analyzed separately. The number of affected subjects will be reported.

Refractory hypotension is defined as a 20% drop of mean arterial pressure (MAP) below specific age-related criteria for more than 30 minutes. The number of subjects with any refractory hypotension from end of surgery until 48 hours will be compared between groups.