Reduced breathing variability as a predictor of unsuccessful patient separation from mechanical ventilation*

Wysocki, Marc; Cracco, Christophe; Teixeira, Antônio R. L.; Mercat, Alain; Diehl, Jean‐Luc; Lefort, Yannick; Derenne, Jean‐Philippe; Similowski, Thomas

doi:10.1097/01.ccm.0000227175.83575.e9

Cited by 166 publications

(123 citation statements)

References 26 publications

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“…A decreased variability is associated with respiratory disease in adults (29) and in infants (22), and a lower variability is a predictor of weaning failure (30). In this study, the patients exhibited a large variability of their ventilatory drive whatever the mode, as reflected by large coefficient of variation of peak Edi.…”

Section: Respiratory Variabilitymentioning

confidence: 77%

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

et al. 2012

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Background: Neurally adjusted ventilatory assist (NaVa) is a mode of ventilation controlled by the electrical activity of the diaphragm (edi). The aim was to evaluate patient-ventilator interaction in infants during NaVa as compared with conventional ventilation. Methods: Infants were successively ventilated with NaVa, pressure control ventilation (PcV), and pressure support ventilation (PsV). edi and ventilator pressure (Pvent) waveforms were compared and their variability was assessed by coefficients of variation. results: Ten patients (mean age 4.3 ± 2.4 mo and weight 5.9 ± 2.2 kg) were studied. In PcV and PsV, 4 ± 4.6% and 6.5 ± 7.7% of the neural efforts failed to trigger the ventilator. This did not occur during NaVa. Trigger delays were shorter with NaVa as compared with PcV and PsV (93 ± 20 ms vs. 193 ± 87 ms and 135 ± 29 ms). During PcV and PsV, the ventilator cycled off before the end of neural inspiration in 12 ± 13% and 21 ± 19% of the breaths (0 ± 0% during NaVa). During PcV and PsV, 24 ± 11% and 25 ± 9% of the neural breath cycle was asynchronous with the ventilator as compared with 11 ± 3% with NaVa. a large variability was observed for edi in all modes, which was transmitted into Pvent during NaVa (coefficient of variation: 24 ± 8%) and not in PcV (coefficient of variation 2 ± 1%) or PsV (2 ± 2%). conclusion: NaVa improves patient-ventilator interaction and delivers adequate ventilation with variable pressure in infants.c onventional modes of mechanical ventilation are clearly limited in their ability to provide synchrony between the patient and the assist delivered, as demonstrated repeatedly in adults (1,2) and more recently in children (3). Patientventilator asynchrony has been associated with poor clinical outcome (1,2,4). Despite the attempt to improve synchrony with "patient-triggered" modes such as pressure control ventilation (PCV) or pressure support ventilation (PSV), 25% of adult patients show more than 10% asynchrony with the ventilator (1,2,5). In pediatric patients, synchrony is particularly difficult to achieve because of the small tidal volumes, high respiratory rates, and weak airway flows and pressures. Ironically, during synchronized intermittent mandatory ventilation, more than half of the patient's breathing cycle is spent in asynchrony (3) with the ventilator.Besides the poor timing between the patient and the ventilator, patient-ventilator asynchrony also includes the inability of the ventilator to respond to patient demand and the natural breath-to-breath variability. Respiratory variability is a sign of a well functioning respiratory system (6). By definition, PCV and PSV deliver fixed levels of assist, thereby offering no possibility to respond to the patient's respiratory demand and variability.Neurally adjusted ventilatory assist (NAVA) is a mode of mechanical ventilation that delivers assist in time and in proportion to the electrical activity of the diaphragm (Edi) on a breath-by-breath basis (7). Numerous studies have shown that NAVA efficiently unloads the respirat...

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Section: Respiratory Variabilitymentioning

confidence: 77%

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

et al. 2012

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“…7,[11][12][13] The SBT involves clinical observation and therefore will never reach perfect inter-observer agreement. Given the importance of this test, however, it is pertinent to recognize and quantify this limitation of the test and to identify potentially correctable factors to minimize its variability.…”

Section: Discussionmentioning

confidence: 99%

Inter-Observer Agreement of Spontaneous Breathing Trial Outcome

et al. 2014

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BACKGROUND: Spontaneous breathing trials (SBTs) are a very important test in the weaning process. The trial involves evaluation of multiple objective and subjective variables. These characteristics could lead to variability in interpreting outcomes with important clinical implications. We aimed to measure the inter-observer agreement between respiratory therapists when analyzing SBT outcomes. METHODS: In the context of a respiratory therapist-driven weaning protocol, 2 respiratory therapists independently interpreted the subjective variables (use of accessory muscles, agitation, and diaphoresis) and the overall outcome of SBTs (success vs failure) performed in adult subjects mechanically ventilated for any duration. Raw agreements between respiratory therapists and kappa statistics were calculated. RESULTS: One-hundred fifty-one SBTs were interpreted. The overall trial outcome raw agreement was 93.3% (95% CI 88.2-96.3) and kappa 0.63 (95% CI 0.47-0.79). Raw agreement for subjective variables ranged between 92.1% (agitation) and 99.3% (diaphoresis). The group with disagreements in overall trial outcome had higher breathing frequency, breathing-frequency-to-tidal-volume ratio, and systolic blood pressure prior to the trial. CONCLUSIONS: Within a respiratory therapist-driven weaning protocol, we found a near 90% inter-observer agreement in the interpretation of SBT outcomes. Our findings illustrate the complexity of interpreting fluctuating subjective and objective variables and their integration into one result: SBT success versus failure. Refining the definitions of variables and their limits for failure along with education might reduce this variability.

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“…However, these studies are not comparable since the authors implemented different weaning protocols in heterogeneous groups of patients and examined various indices of both breathing pattern variability (linear) and complexity (nonlinear) that by their nature capture different aspects of signal dynamics. It seems that the study of Wysocki [78] performed better, since it was conducted in 5 medical centres, stationarity tests were done and possible bias in the time series analysis was significantly controlled. Furthermore, lack of ventilatory support during weaning trial could have eliminated any possible impact of positive pressure ventilation upon breathing variability and could be responsible for the different findings between this and the first two studies.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, Wysocki and colleagues [78] examined breathing variability in 46 medical and surgical patients during 60 minutes spontaneous breathing trials (SBT) and during a 5-month period in four French tertiary university hospitals' ICUs. There were 32 successful and 14 failure weaning cases.…”

Section: Breathing Variability and Complexity Indices As Weaning Predmentioning

confidence: 99%

Fractal Physiology, Breath-to-Breath Variability and Respiratory Diseases: An Introduction to Complex Systems Theory Application in Pulmonary and Critical Care Medicine

Papaioannou¹,

Pneumatikos²

2013

Practical Applications in Biomedical Engineering

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Reduced breathing variability as a predictor of unsuccessful patient separation from mechanical ventilation*

Abstract: In intensive care unit patients undergoing a spontaneous breathing trial, breathing variability is greater in patients successfully separated from the ventilator and the endotracheal tube. Variability indices are sufficient to separate success from failure cases.

Cited by 166 publications

References 26 publications

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

Neurally adjusted ventilatory assist improves patient–ventilator interaction in infants as compared with conventional ventilation

Inter-Observer Agreement of Spontaneous Breathing Trial Outcome

Fractal Physiology, Breath-to-Breath Variability and Respiratory Diseases: An Introduction to Complex Systems Theory Application in Pulmonary and Critical Care Medicine

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