Increased ventilatory variability and complexity in patients with hyperventilation disorder.
Plamen BokovMarie-Noëlle FiammaBrigitte Chevalier-BidaudCécile ChenivesseChristian StrausCaroline Sévoz-CoucheChristophe DelclauxPublished in: Journal of applied physiology (Bethesda, Md. : 1985) (2016)
It has been hypothesized that hyperventilation disorders could be characterized by an abnormal ventilatory control leading to enhanced variability of resting ventilation. The variability of tidal volume (VT) often depicts a nonnormal distribution that can be described by the negative slope characterizing augmented breaths formed by the relationship between the probability density distribution of VT and VT on a log-log scale. The objectives of this study were to describe the variability of resting ventilation [coefficient of variation (CV) of VT and slope], the stability in respiratory control (loop, controller and plant gains characterizing ventilatory-chemoresponsiveness interactions) and the chaotic-like dynamics (embedding dimension, Kappa values characterizing complexity) of resting ventilation in patients with a well-defined dysfunctional breathing pattern characterized by air hunger and constantly decreased PaCO2 during a cardiopulmonary exercise test. Compared with 14 healthy subjects with similar anthropometrics, 23 patients with hyperventilation were characterized by increased variability of resting tidal ventilation (CV of VT median [interquartile]: 26% [19-35] vs. 36% [28-48], P = 0.020; slope: -6.63 [-7.65; -5.36] vs. -3.88 [-5.91; -2.66], P = 0.004) that was not related to increased chemical drive (loop gain: 0.051 [0.039-0.221] vs. 0.044 [0.012-0.087], P = 0.149) but that was related to an increased ventilatory complexity (Kappa values, P < 0.05). Plant gain was decreased in patients and correlated with complexity (with Kappa 5 - degree 5: Rho = -0.48, P = 0.006). In conclusion, well-defined patients suffering from hyperventilation disorder are characterized by increased variability of their resting ventilation due to increased ventilatory complexity with stable ventilatory-chemoresponsiveness interactions.
Keyphrases
- heart rate
- heart rate variability
- end stage renal disease
- ejection fraction
- respiratory failure
- nuclear factor
- newly diagnosed
- prognostic factors
- mechanical ventilation
- physical activity
- transcription factor
- peritoneal dialysis
- immune response
- patient reported outcomes
- toll like receptor
- patient reported
- inflammatory response
- extracorporeal membrane oxygenation
- acute respiratory distress syndrome