Determinants of effective ventilation during nasal intermittent positive pressure ventilation

Parreira, Verônica Franco; Jounieaux, Vincent; Delguste, Pierre; Aubert, Geneviève; Dury, Myriam; Rodenstein, Daniel

doi:10.1183/09031936.97.10091975

Cited by 25 publications

(12 citation statements)

References 30 publications

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“…This can be explained by the need, in these patients, to modify the Pa,CO 2 to a greater extent, which could cause ''resistance'' to the ventilation, as has been described previously [24]. For stable patients, there was a significant correlation between the presence of abnormalities in ResLink TM data and a reduced efficacy of NIV, particularly in terms of Pa,O 2 , pH and HCO 3 -.…”

Section: Discussionmentioning

confidence: 74%

“…There are several possible explanations for this. One is that greater modification of Pa,CO 2 as a result of more hermetic ventilation could promote the occurrence of glottal closure episodes [24]. Another is that the use of FM predominantly induces mouth breathing, which may promote significant narrowing of the retropalatal distance predisposing to oropharyngeal obstruction [34].…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluating noninvasive ventilation using a monitoring system coupled to a ventilator: a bench-to-bedside study

Rabec¹,

Georges²,

Kabeya³

et al. 2009

Eur Respir J

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Empirically determined noninvasive ventilation (NIV) settings may not achieve optimal ventilatory support. Some ventilators include monitoring modules to assess ventilatory quality. We conducted a bench-to-bedside study to assess the ventilatory quality of the VPAP TM IIIResLink TM (ResMed, North Ryde, Australia).We tested the accuracy of minute ventilation (MV) and leak calculations given by VPAP TM IIIResLink TM compared to those measured by a bench model at varied leak levels and ventilator settings. We systematically assessed NIV efficacy using this system from 2003 to 2006. Ventilation was considered inadequate if leak (.24 L?min -1 ), continuous desaturation (.30% of the trace) or desaturation dips (.3%) were present. On the bench test, both methods were highly correlated (r50.947, p.0.0001 and r50.959, p,0.0001 for leak and MV, respectively). We performed 222 assessments in 169 patients (aged 66.42¡16 yrs, 100 males). Abnormalities were detected on 147 (66%) out of 222 occasions. Leak was the most common abnormality (34.2%) followed by desaturation dips (23.8%). The most effective therapeutic solutions were a chin strap if leak was detected (61.2%) and expiratory positive airway pressure increase for desaturation dips (59.5%). In 15.7% of cases, when abnormalities persisted, a polygraphy was performed.The systematic use of this device enables NIV to be optimised, limiting the indication of sleep studies to complex cases. KEYWORDS: Bench testing, bi-level positive airway pressure, clinical evaluation, monitoring, noninvasive ventilation, respiratory failure N oninvasive ventilation (NIV) has been demonstrated to be effective treatment in respiratory failure. In some cases, however, the clinical results may be less than expected, despite using the correct technique. When NIV is initiated, the ventilator settings are determined empirically based on clinical evaluation of underlying disease, patient tolerance when awake, and diurnal blood gas variations [1]. However, NIV is predominantly applied at night [2], when profound ventilatory changes may occur, particularly in patients with respiratory failure [3]. Such changes include modifications of ventilatory control, upper airway patency and respiratory muscle recruitment. Consequently, modulating NIV settings during the day and underestimating these physiological differences may lead to suboptimal patientventilator interaction that reduces NIV efficacy.Moreover, NIV uses a non-hermetic technique, which poses the possible risk of leak. Leakage may be absent or minimal when the patient is awake and may worsen during sleep as a result of the loss of voluntary control and decreased muscle tone. Thus, NIV settings chosen empirically on daytime evaluation may not predict optimal nocturnal ventilatory support. Consequently, NIV effectiveness may be more correctly assessed by sleep studies than through daytime assessment [1]. Ideally this requires complete polysomnography (PSG) or ventilatory polygraphy (PG) at the time of initiation to NIV. However, it is n...

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Section: Discussionmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Evaluating noninvasive ventilation using a monitoring system coupled to a ventilator: a bench-to-bedside study

Rabec¹,

Georges²,

Kabeya³

et al. 2009

Eur Respir J

View full text Add to dashboard Cite

show abstract

“…These choices were made in order to simplify data presentation, and to represent the range of settings commonly encountered clinically [10]. The two leaks were selected to range below and above those measured in a previous clinical study [3], and ideal settings were used for NPPV based on recommendations in the literature [8,9]. Third, the effects of leak on ventilator triggering or cycling during spontaneous breathing were not tested, so the observations are most relevant to situations where controlled breathing predominates, such as in neuromuscular patients during sleep [3].…”

Section: Discussionmentioning

confidence: 99%

“…min -1 in all of the experiments to reflect commonly recommended breathing rates for noninvasive ventilation [8,9]. IPAP/EPAP settings were 18 and 5 cmH 2 O respectively for the BiPAP (in both T and S/T modes), 335, and Quantum ventilators.…”

Section: Experimental Settingsmentioning

confidence: 99%

Leak compensation in positive pressure ventilators: a lung model study

Mehta

McCool²,

Hill³

2001

Eur Respir J

119

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Leak compensating abilities of six different positive pressure ventilators commonly used to deliver noninvasive positive pressure ventilation, including the bilevel positive airway pressure (BiPAP) S/T-D and Quantum (Respironics Inc, Murrysville, PA, USA), 335 and O'NYX (Mallinckrodt Inc, St Louis, MO, USA), PLV 102 (Respironics), and Siemens Servo 900C (Siemens Inc, Danvers, MA, USA).Using a test lung model, compensatory capabilities of the ventilators were tested for smaller and larger leaks using the assist/control or timed modes. Back-up rate was 20·min−1, inspiratory pressure was 18 cmH2O, and expiratory pressure was 5 cmH2O.It was found that even in the absence of air leaking, delivered tidal volume differed substantially between the ventilators during use of pressure-targeted modes, depending on inspiratory flows, inaccuracies in setversusdelivered pressures, and inspiratory duration. Also during pressure-targeted ventilation, increasing thetI/ttotup to, but not beyond, 0.5 improved compensation by lengthening inspiratory duration, whereas use of a sensitive flow trigger setting tended to cause autocycling during leaking, interfering with compensation. Leaking interfered with cycling of the BiPAP S/T, inverting the I:E ratio, shortening expiratory time, and reducing delivered tidal volume. Volume-targeted modes achieved limited compensation for small air leaks, but compensated poorly for large leaks.To conclude, leak-compensating capabilities differ markedly between ventilators but pressure-targeted ventilators are preferred for noninvasive positive pressure ventilation in patients with substantial air leaking. Adequate inspiratory flows and durations should be used, triggering sensitivity should be adjusted to prevent autocycling, and a mechanism should be available to limit inspiratory time and avoid I:E ratio inversion.

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“…The glottis is an essential structure in nIPPV, since, in response to assisted ventilation with positive pressures, it can substantially narrow and even, completely close, thus increasing the risks of leaks, decreasing the usefulness of nIPPV and impairing sleep quality [12,13]. It has been shown that changing the delivered tidal volume, inspiratory flow and ventilatory frequency, or the positive inspiratory pressure (as well as manipulating the ventilatory mode), can influence the glottic response and improve the ventilation effectively reaching the lungs during sleep [14,15]. TESCHLER et al [10] attributed the decrease in ventilation and the poor sleep quality to the presence of leaks (i.e.…”

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confidence: 99%