Breathing frequency and use of expiratory muscles do influence the dynamic positive end-expiratory pressure

Abstract

End-expiratory air trapping due to obstructive airway disease can be estimated through the measurement of intrinsic positive end-expiratory pressure PEEPi. The influence of breathing-frequency and use of expiratory muscles on PEEPi were measured in 10 normal and 10 chronic bronchitic patients (COPD). Insignificant control values of PEEPi increased to measurable values at high breathing rate in normal subjects. Control values were higher in COPD patients and increased at fast breathing rate. When corrected for the use of expiratory muscles according to simultaneous gastric pressure drop, PEEPi decreased in COPD, but still increased at high rate. We conclude that modifying the respiratory rate can increase PEEPi values independently of the severity of airway obstruction and the use of expiratory muscles. Before estimating the pathological value of a PEEPi measurement or evaluating the effects of a treatment, we always need to know the simultaneous breathing frequency.

Intrinsic positive end-expiratory pressure in Acute Respiratory Distress Syndrome (ARDS) Network subjects

“…Second, mean respiratory rate during the 6 mL/kg strategy was 34 breaths/min, considerably higher than the mean respiratory rates of the subjects in the 6 mL/kg group of both the ARDS Network study and our subgroup. Our work and previous studies have demonstrated an association between respiratory rate and intrinsic PEEP (15,19). Finally, the timing of intrinsic PEEP measurements differed between these studies.…”

Effect of Yoga in Chronic Obstructive Pulmonary Disease

“…6,25,26 In chronic conditions such as congestive heart failure, slowing respiratory rate as practiced in yoga has shown to reduce the sensation of dyspnea and improve exercise performance, 24 whereas studies in patients with COPD have shown increased respiratory muscle recruitment with pursed lip breathing, which again is a component of pranayama, 27 relief of dyspnea and increased leg effort after lower extremity exercise training, 28 and reduction in dynamic hyperinflation with lower respiratory rates as achieved in yoga. 29,30 Potential limitations of our study merit consideration. First, the QOL was assessed on a short-term basis.…”

Use of Continuous Negative Pressure Around the Chest Increases Exercise Performance in Chronic Obstructive Pulmonary Disease Patients: A Pilot Study

“…In the current study, we did not measure expiratory muscle activity, which has been shown to occur with the application of CPAP during exercise (4,10). Furthermore, we did not measure actual PEEPi.…”

“…If a patient did not have PEEPi, the application of CPAP and CNP would ordinarily cause hyperinflation (11)(12)(13). The decrease in respiratory rate that occurred with CNP could also have resulted in a decreased PEEPi (4,5).…”

“…C hronic obstructive pulmonary disease (COPD) patients may develop hyperinflation and intrinsic positive end-expiratory pressure (PEEPi) (1)(2)(3). This is more likely to occur during exercise when the respiratory rate is increased (4,5), which results in a major increase in the inspiratory work of breathing and, consequently, may limit exercise capability.…”