Carglumic acid enhances rapid ammonia detoxification in classical organic acidurias with a favourable risk-benefit profile: a retrospective observational study.

BACKGROUND: Isovaleric aciduria (IVA), propionic aciduria (PA) and methylmalonic aciduria (MMA) are inherited organic acidurias (OAs) in which impaired organic acid metabolism induces hyperammonaemia arising partly from secondary deficiency of N-acetylglutamate (NAG) synthase. Rapid reduction in plasma ammonia is required to prevent neurological complications. This retrospective, multicentre, open-label, uncontrolled, phase IIIb study evaluated the efficacy and safety of carglumic acid, a synthetic structural analogue of NAG, for treating hyperammonaemia during OA decompensation. METHODS: Eligible patients had confirmed OA and hyperammonaemia (plasma NH3 > 60 µmol/L) in ≥1 decompensation episode treated with carglumic acid (dose discretionary, mean (SD) first dose 96.3 (73.8) mg/kg). The primary outcome was change in plasma ammonia from baseline to endpoint (last available ammonia measurement at ≤18 hours after the last carglumic acid administration, or on Day 15) for each episode. Secondary outcomes included clinical response and safety. RESULTS: The efficacy population (received ≥1 dose of study drug and had post-baseline measurements) comprised 41 patients (MMA: 21, PA: 16, IVA: 4) with 48 decompensation episodes (MMA: 25, PA: 19, IVA: 4). Mean baseline plasma ammonia concentration was 468.3 (±365.3) µmol/L in neonates (29 episodes) and 171.3 (±75.7) µmol/L in non-neonates (19 episodes). At endpoint the mean plasma NH3 concentration was 60.7 (±36.5) µmol/L in neonates and 55.2 (±21.8) µmol/L in non-neonates. Median time to normalise ammonaemia was 38.4 hours in neonates vs 28.3 hours in non-neonates and was similar between OA subgroups (MMA: 37.5 hours, PA: 36.0 hours, IVA: 40.5 hours). Median time to ammonia normalisation was 1.5 and 1.6 days in patients receiving and not receiving concomitant scavenger therapy, respectively. Although patients receiving carglumic acid with scavengers had a greater reduction in plasma ammonia, the endpoint ammonia levels were similar with or without scavenger therapy. Clinical symptoms improved with therapy. Twenty-five of 57 patients in the safety population (67 episodes) experienced AEs, most of which were not drug-related. Overall, carglumic acid seems to have a good safety profile for treating hyperammonaemia during OA decompensation. CONCLUSION: Carglumic acid when used with or without ammonia scavengers, is an effective treatment for restoration of normal plasma ammonia concentrations in hyperammonaemic episodes in OA patients.

Cardiac preload responsiveness in children with cardiovascular dysfunction or dilated cardiomyopathy: a multicenter observational study.

OBJECTIVES: To characterize cardiac preload responsiveness in pediatric patients with cardiovascular dysfunction and dilated cardiomyopathy using global end-diastolic volume index, stroke volume index, cardiac index, and extravascular lung water index. DESIGN: Prospective multicenter observational study. SETTING: Medical/surgical PICUs of seven Spanish University Medical Centers. PATIENTS: Seventy-five pediatric patients (42 male, 33 female), median age 36 months (range, 1-207 mo), were divided into three groups: normal cardiovascular status, cardiovascular dysfunction, and dilated cardiomyopathy. INTERVENTIONS: All patients received hemodynamic monitoring with PiCCO2 (Pulsion Medical System SE, Munich, Germany). We evaluated 598 transpulmonary thermodilution sets of measurements. In 40 patients, stroke volume index, cardiac index, and global end-diastolic volume index were measured before and after 66 fluid challenges and loadings to test fluid responsiveness at different preload levels. MEASUREMENTS AND MAIN RESULTS: Global end-diastolic volume versus predicted body surface area exhibits a power-law relationship: Global end-diastolic volume = 488.8·predicted body surface area (r = 0.93). Four levels of cardiac preload were established from the resulting "normal" global end-diastolic volume index (= 488.8·predicted body surface area). Stroke volume index and cardiac index versus global end-diastolic volume index/normal global end-diastolic volume index built using a linear mixed model analysis emulated Frank-Starling curves: in cardiovascular dysfunction group, stroke volume index (geometric mean [95% CI]) was 27 mL/m (24-31 mL/m) at "≤ 0.67 times normal global end-diastolic volume index," 37 mL/m (35-40 mL/m) at "> 0.67 ≤ 1.33 times normal global end-diastolic volume index" (Δ stroke volume index = 35%; p < 0.0001; area under the receiver-operating characteristic curve = 75%), 45 mL/ m (41-49 mL/m) at "> 1.33 ≤ 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = 21%; p < 0.0001; area under the receiver-operating characteristic curve = 73%), and 47 mL/m (43-51 mL/m) at "> 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = 4%; p = 1; area under the receiver-operating characteristic curve = 54%). In dilated cardiomyopathy group, stroke volume index was 21 mL/m (17-26 mL/m) at "> 0.67 ≤ 1.33 times normal global end-diastolic volume index," 27 mL/m (21-34 mL/ m) at "> 1.33 ≤ 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = 29%; p = 0.005; area under the receiver-operating characteristic curve = 64%), and 25 mL/m (20-32 mL/m) at "> 1.51 times normal global end-diastolic volume index" (Δ stroke volume index = -8%; p = 1; area under the receiver-operating characteristic curve = 54%). CONCLUSIONS: This study provides "normal" values for global end-diastolic volume index and limits of cardiac preload responsiveness in pediatric patients with cardiovascular dysfunction and dilated cardiomyopathy: 1.33 times normal global end-diastolic volume index represents the upper limit of patent cardiac preload responsiveness, with the highest expected responsiveness being below 0.67 times normal global end-diastolic volume index. The maximum response of the Frank-Starling relationship and therefore the level of no additional preload reserve is 1.33 to 1.51 times normal global end-diastolic volume index. Above 1.51 times normal global end-diastolic volume index preload responsiveness is unlikely, and the risk of pulmonary edema is maximal.

Noninvasive ventilation in pediatric acute respiratory failure by means of a conventional volumetric ventilator.

BACKGROUND: Acute respiratory failure (ARF) is one of the main causes for admission to pediatric intensive care unit (PICU). This study aimed to evaluate the feasibility and outcome of noninvasive ventilation (NIV) by a volumetric ventilator with a specific mode in pediatric acute respiratory failure. METHODS: A three-year prospective non-controlled study was undertaken in children with ARF who had received NIV delivered by Evita 2 Dura with NIV mode through a nonvented oronasal mask. RESULTS: Thirty-two episodes of ARF were observed in 26 patients. Pneumonia was observed in most of the children (46.8%). Pediatric logistic organ dysfunction (PELOD) score was 12.4% ± 24% (range 0-84%). Peak inspiratory pressure was 18.5 ± 2.7 cmH2O, positive end-expiratory pressure 5.7 ± 1.1 cmH2O, pressure support 10.5 ± 2.7 cmH2O, and mean pressure 9.2 ± 2 cmH2O. The clinical score was improved progressively within the first 6 hours. Before the initiation of NIV, respiratory rate was 41.7 ± 16.3, heart rate 131.6 ± 25.8, systolic arterial pressure 108 ± 19.5, diastolic arterial pressure 58.2 ± 13.9, pH 7.33 ± 0.12, pCO2 55.1 ± 20.2, SatO2 87.8 ± 9.9 and FiO2 0.55 ± 0.25. There was a significant improvement in the respiratory rate, heart rate, pH, pCO2 and SatO2 at 2-4 hours. This improvement was kept throughout the first 24 hours. The level of FiO2 was significantly lower at 24 hours. Radiological improvement was observed after 24 hours in 17 out of 26 patients. The duration of NIV was 85.4 ± 62.8 hours. Complications were defined as minor. Only 4 patients required intubation. All patients survived. CONCLUSIONS: NIV can be successfully applied to infants and children with ARF using this volumetric ventilator with specific NIV mode. It should be considered particularly in children whose underlying condition warrants avoidance of intubation.