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BackgroundCommon, operational definitions are crucial to assess interventions and outcomes related to pediatric mechanical ventilation. These definitions can reduce unnecessary variability among research and quality improvement efforts, to ensure findings are generalizable, and can be pooled to establish best practices.Research questionCan we establish operational definitions for key elements related to pediatric ventilator liberation using a combination of detailed literature review and consensus-based approaches?Study design and methodsA panel of 26 international experts in pediatric ventilator liberation, two methodologists, and two librarians conducted systematic reviews on eight topic areas related to pediatric ventilator liberation. Through a series of virtual meetings, we established draft definitions that were voted upon using an anonymous web-based process. Definitions were revised by incorporating extracted data gathered during the systematic review and discussed in another consensus meeting. A second round of voting was conducted to confirm the final definitions.ResultsIn eight topic areas identified by the experts, 16 preliminary definitions were established. Based on initial discussion and the first round of voting, modifications were suggested for 11 of the 16 definitions. There was significant variability in how these items were defined in the literature reviewed. The final round of voting achieved ≥ 80% agreement for all 16 definitions in the following areas: what constitutes respiratory support (invasive mechanical ventilation and noninvasive respiratory support), liberation and failed attempts to liberate from invasive mechanical ventilation, liberation from respiratory support, duration of noninvasive respiratory support, total duration of invasive mechanical ventilation, spontaneous breathing trials, extubation readiness testing, 28 ventilator-free days, and planned vs rescue use of post-extubation noninvasive respiratory support.InterpretationWe propose that these consensus-based definitions for elements of pediatric ventilator liberation, informed by evidence, be used for future quality improvement initiatives and research studies to improve generalizability and facilitate comparison.

This article describes a new approach for quantitative evaluation of respiration in the pediatric intensive care unit (PICU). Video sequences of thorax movements are recorded by two depth cameras to cover the 3-D surface of the torso and its lateral sides. The breathing activity implies a frame-by-frame surface deformation, which can be described by the volume variation of reconstructed surfaces between the consecutive video frames. A quantitative evaluation of the breathing pattern is then performed through a subtraction technique, thereby detecting the volume variation between the subsequent frames. A high-fidelity simulation was performed in a realistic environment designed for critically ill children. The simulation was then followed by a real-world evaluation, involving two newborn babies (one female and one male) who required ventilator support. The breathing signal patterns resulting from our approach were compared to those measured by mechanical ventilation in terms of their waveforms, evaluating the most significant dynamic parameters: tidal volume, respiratory rate, and minute ventilation. Our experimental study showed a significant agreement between the proposed 3-D imaging system and the gold standard method in estimating respiratory waveforms and parameters. This article presents the following innovations. First, we suggest a 3-D imaging system specifically designed for PICUs based on a contactless design. Second, we propose an efficient positioning mechanism for the cameras, offering a very high spatial coverage of the thoracoabdominal zone and considering the PICU constraints. Finally, we propose an objective vision-based method to quantitatively measure respiration for spontaneous breathing patients in PICUs. [ABSTRACT FROM AUTHOR]

BACKGROUND: The present study aimed to characterize the behavior of 3 components of respiratory muscle function during mechanical ventilation weaning in children to better understand the respective impact of a spontaneous breathing trial on ventilatory mechanical action (esophageal pressure [Pes], ventilatory demand (electrical activity of the diaphragm [EAdi]), and oxygen consumption. METHODS: This was a prospective single-center study. All children > 1 months and <18 y old who were intubated and on mechanical ventilation, and who were hospitalized in the pediatric ICU were eligible. Subjects considered as ready to extubate were included. Simultaneous recordings of oxygen consumption, Pes, and EAdi were performed during 3 steps: before, during, and after the spontaneous breathing test. RESULTS: Twenty subjects (median age, 5.5 mo) were included. Half of them were admitted for a respiratory cause. The increase in Pes swings and esophageal pressure-time product during the spontaneous breathing trial was not significant (P = .33 and P = .75, respectively), and a similar trend was observed with peak EAdi (P = .06). Oxygen consumption obtained by indirect calorimetry was stable in the 3 conditions (P = .98). CONCLUSIONS: In these children who were critically ill, a spontaneous breathing trial induced a moderate and nonsignificant increase in work of breathing, as reflected by the respiratory drive with EAdi and respiratory mechanics with Pes. However, indirect calorimetry did not seem to be a sensitive tool to assess respiratory muscle function during the weaning phase in children who were on mechanical ventilation, especially when work of breathing was slightly increased. [ABSTRACT FROM AUTHOR]

Background: We aimed (1) to describe the characteristics of patient-ventilator asynchrony in a population of critically ill children, (2) to describe the risk factors associated with patient-ventilator asynchrony, and (3) to evaluate the association between patient-ventilator asynchrony and ventilator-free days at day 28. Methods: In this single-center prospective study, consecutive children admitted to the PICU and mechanically ventilated for at least 24 h were included. Patient-ventilator asynchrony was analyzed by comparing the ventilator pressure curve and the electrical activity of the diaphragm (Edi) signal with (1) a manual analysis and (2) using a standardized fully automated method. Results: Fifty-two patients (median age 6 months) were included in the analysis. Eighteen patients had a very low ventilatory drive (i.e., peak Edi < 2 µV on average), which prevented the calculation of patient-ventilator asynchrony. Children spent 27% (interquartile 22-39%) of the time in conflict with the ventilator. Cycling-off errors and trigger delays contributed to most of this asynchronous time. The automatic algorithm provided a NeuroSync index of 45%, confirming the high prevalence of asynchrony. No association between the severity of asynchrony and ventilator-free days at day 28 or any other clinical secondary outcomes was observed, but the proportion of children with good synchrony was very low. Conclusion: Patient-ventilator interaction is poor in children supported by conventional ventilation, with a high frequency of depressed ventilatory drive and a large proportion of time spent in asynchrony. The clinical benefit of strategies to improve patient-ventilator interactions should be evaluated in pediatric critical care. [ABSTRACT FROM AUTHOR]

BACKGROUND: Recent findings suggest that using alveolar P... (P...) estimated by volumetric capnography in the Bohr equation instead of P... (Enghoff modification) could be appropriate for the calculation of physiological dead space to tidal volume ratio (VD/VT Bohr and VD/VT Enghoff, respectively). We aimed to describe the relationship between these 2 measurements in mechanically ventilated children and their significance in cases of ARDS. METHODS: From June 2013 to December 2013, mechanically ventilated children with various respiratory conditions were included in this study. Demographic data, medical history, and ventilatory parameters were recorded. Volumetric capnography indices (NM3 monitor) were obtained over a period of 5 min preceding a blood sample. Bohr's and Enghoff's dead space, S2 and S3 slopes, and the S2/S3 ratio were calculated breath-by-breath using dedicated software (FlowTool). This study was approved by Ste-Justine research ethics review board. RESULTS: Thirty-four subjects were analyzed. Mean VD/VT Bohr was 0.39 ± 0.12, and VD/VT Enghoff was 0.47 ± 0.13 (P = .02). The difference between VD/VT Bohr and VD/VT Enghoff was correlated with P.../F... and with S2/S3. In subjects without lung disease (P.../F... ≥ 300), mean VD/VT Bohr was 0.36 ± 0.11, and VD/VT Enghoff was 0.39 ± 0.11 (P = .056). Two children with status asthmaticus had a major difference between VD/VT Bohr and VD/VT Enghoff in the absence of a low P.../F... CONCLUSIONS: This study suggests that VD/VTBohr and VD/VT Enghoff are not different when there is no hypoxemia (P.../F... > 300) except in the case of status asthmaticus. In subjects with a low P.../F..., the method to measure VD/VT must be reported, and results cannot be easily compared if the measurement methods are not the same. [ABSTRACT FROM AUTHOR]

The article presents a study to evaluate the humidification performance of a large number of adult heat and moisture exchangers (HMEs). It assesses 48 devices using a bench test apparatus that simulated real-life physiologic ventilation conditions, and performs three hygrometric measurements for each device. The research suggests that several HMEs performed poorly and should not be used as HMEs.