Cardiorespiratory signal analysis in extremely preterm infants during the peri-extubation period
Bibliographic record
Abstract
Background: Mechanical ventilation (MV) is common among extremely preterm (EPT) infants and prediction/prevention of extubation failure remains an enigma. One controversial approach is the use of an endotracheal continuous positive airway pressure (ETT-CPAP) trial while observing stability of vital signs. After extubation, infants are treated with some type of non- invasive respiratory support: nasal CPAP (NCPAP), high flow nasal cannula (HFNC), nasal intermittent positive pressure ventilation (NIPPV), and non-invasive neurally adjusted ventilatory assist (NIV-NAVA). Despite many trials, due to significant methodological issues, the superiority of a particular type is not entirely clear, although there are some encouraging findings with patient-synchronized ventilation through NIPPV and NIV-NAVA. In the neonatal intensive care unit (NICU) vital signs are continuously monitored and these signals are available for analyses of cardiorespiratory behavior. Investigations include analysis of heart rate variability (HRV), diaphragmatic activity, and respiratory variability (RV). While these measures are typically used in research settings, there is growing evidence for its clinical usefulness in providing more precise and individualized information.Objectives: The overall aim of this thesis is to investigate cardiorespiratory behavior of EPT infants during the peri-extubation period. The specific objectives are to evaluate the effects of an ETT-CPAP trial prior to extubation, and different types of non-invasive respiratory support provided after extubation on the cardiorespiratory behavior. The utility of cardiorespiratory behavior measures for extubation outcomes was also investigated.Methods: A series of prospective crossover studies were designed and performed. All studies were done in the Montreal Children’s Hospital NICU and included EPT infants with birth weight ≤1250 grams undergoing their first elective extubation attempt. The first study investigated and compared measures of cardiorespiratory behaviour between a period of MV and a 5min ETT- CPAP trial, during the pre-extubation period. The other studies were performed shortly after extubation, a period of transition and clinical instability. The following comparisons were done: NCPAP vs HFNC, and NCPAP, NIPPV, vs NIV-NAVA. Cardiorespiratory signals included electrocardiogram (ECG) and electrical activity of the diaphragm (Edi). ECGs were analyzed to extract several HRV parameters. Edi signals were analyzed to extract diaphragmatic activity parameters, including measures of respiratory effort and timing, and RV. Extubation failure was defined as reintubation within 7 days of extubation.Results: The analysis of these signals during the peri-extubation period yielded important findings related to cardiorespiratory behavior of EPT infants. The use of a 5min ETT-CPAP prior to extubation was associated with increased respiratory efforts and variability of these efforts but more consistent breathing timing. Shortly after extubation, HRV parameters were increased during HFNC when compared to NCPAP, but only in a subgroup of infants successfully extubated. This finding raised the possibility that inability to increase HRV when provided with less support may be a sign of imminent failure. NIV-NAVA and NIPPV were associated with lower respiratory efforts and higher RV when compared to NCPAP. Interestingly, RV parameters demonstrated strong accuracies (0.75-1.00) to predict extubation outcomes both pre- and post-extubation.Conclusion: Analysis of individual cardiorespiratory behavior during the peri-extubation period demonstrated potential value in evaluate respiratory efforts and predict impending extubation success or failure. The exploratory investigations of numerous cardiorespiratory parameters in this thesis should encourage performance of larger studies and assist in their design planning. The lack of standardized guidelines for cardiorespiratory signal analysis is a concern
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".