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Michael Dreher

Publications and source records attributed to Michael Dreher.

4 recordsLinked to original sources
PubMed2006

Average volume-assured pressure support in obesity hypoventilation: A randomized crossover trial.

BACKGROUND: Average volume-assured pressure support (AVAPS) has been introduced as a new additional mode for a bilevel pressure ventilation (BPV) device (BiPAP; Respironics; Murrysville, PA), but studies on the physiologic and clinical effects have not yet been performed. There is a particular need to better define the most efficient ventilatory treatment modality for patients with obesity hypoventilation syndrome (OHS). METHODS: In OHS patients who did not respond to therapy with continuous positive airway pressure, the effects of BPV with the spontaneous/timed (S/T) ventilation mode with and without AVAPS over 6 weeks on ventilation pattern, gas exchange, sleep quality, and health-related quality of life (HRQL) assessed by the severe respiratory insufficiency questionnaire (SRI) were prospectively investigated in a randomized crossover trial. RESULTS: Ten patients (mean [+/- SD] age, 53.5 +/- 11.7 years; mean body mass index, 41.6 +/- 12.1 kg/m2; mean FEV1/FVC ratio, 79.4 +/- 6.5%; mean transcutaneous P(CO2) [PtcCO2], 58 +/- 12 mm Hg) were studied. PtcCO2 nonsignificantly decreased during nocturnal BPV-S/T by -5.6 +/- 11.8 mm Hg (95% confidence interval [CI], -14.7 to 3.4 mm Hg; p = 0.188), but significantly decreased during BPV-S/T-AVAPS by -12.6 +/- 12.2 mm Hg (95% CI, -22.0 to -3.2 mm Hg; p = 0.015). Pneumotachographic measurements revealed a higher individual variance of peak inspiratory pressure (p < 0.001) and a trend for lower leak volumes but also for higher tidal volumes during BPV-S/T-AVAPS. The SRI summary scale score improved from 63 +/- 15 to 78 +/- 14 during BPV-S/T (p = 0.004) and to 76 +/- 16 during BPV-S/T-AVAPS (p = 0.014). Sleep quality and oxygen saturation also comparably improved following BPV-S/T and BPV-S/T-AVAPS. CONCLUSION: BPV-S/T substantially improved oxygenation, sleep quality, and HRQL in patients with OHS. AVAPS provided additional benefits on ventilation quality, thus resulting in a more efficient decrease of PtcCO2. However, this did not provide further clinical benefits regarding sleep quality and HRQL.

Adult↗
PubMed2005

Nocturnal non-invasive positive pressure ventilation: physiological effects on spontaneous breathing.

The dynamic process of how non-invasive positive pressure ventilation (NPPV) improves spontaneous ventilation is unclear. Therefore, daytime trends of blood gases and breathing pattern were assessed by measurements 0, 0.5, 1, 3, 7, 11 and 15 h after cessation of nocturnal controlled NPPV in patients with chronic hypercapnic respiratory failure. Twelve patients (six COPD/six restrictive) who were established on NPPV and 12 controls (six COPD/six restrictive) completed. PaCO2 decreased during controlled NPPV (P < 0.02). PaCO2 additionally decreased step by step during the first 3 h of spontaneous breathing after switching from NPPV to spontaneous breathing (P < 0.05), but remained unchanged in controls. The PaCO2 decrease was due to a stepwise increase in tidal volume (P < 0.05) at an unchanged breathing frequency. Accordingly, minute ventilation also stepwise increased (P < 0.03). There were no significant changes in controls. Improvements of PaCO2 and tidal volume occurred even after 5.7 +/- 3.1 days following first NPPV trials, but became more evident after 2 months. Maximal inspiratory mouth pressures increased in chronic obstructive pulmonary disease (COPD) patients (P < 0.05), and respiratory drive increased in restrictive patients (P < 0.05) following 2 months of NPPV. Lung function parameters and inspiratory impedance remained unchanged. Improvements in health-related quality of life were evident and were correlated to the decline of elevated bicarbonate levels (r = 0.72, P < 0.01). In conclusion, there is a stepwise adaptation process lasting 3h when switching from nocturnal controlled NPPV to daytime spontaneous breathing in which tidal volume increases and PaCO2 drops after an initial PaCO2 decrease while on NPPV.

Aged↗
PubMed2005

Outcome of patients with stable COPD receiving controlled noninvasive positive pressure ventilation aimed at a maximal reduction of Pa(CO2).

STUDY OBJECTIVES: The role of noninvasive positive pressure ventilation (NPPV) has been well established in the treatment of acute hypercapnic respiratory failure due to COPD. However, evidence for a sustained improvement in blood gas levels and survival in patients with stable hypercapnic COPD following NPPV is still lacking. There is concern that this might be due to low inspiratory pressures of < 18 cm H2O used in previous studies, which thereby did not achieve a reduction of Pa(CO2). Therefore, the 2-year survival and changes in lung function and blood gas levels were analyzed in patients with stable hypercapnic COPD in whom controlled pressure-limited NPPV was titrated to achieve a maximal improvement in Pa(CO2). DESIGN: Retrospective study between March 1997 and September 2003. SETTING: General ward of a university hospital. PATIENTS: Thirty-four consecutive patients with stable (mean pH 7.40 +/- 0.03) hypercapnic COPD (mean age, 63.4 +/- 9.7 years [+/- SD]; mean body mass index, 28.3 +/- 7.3 kg/m2). MEASUREMENTS AND RESULTS: Daytime Pa(CO2) during spontaneous breathing decreased by 6.9 +/- 8.0 (95% confidence interval, - 9.9 to - 3.9), from 53.3 +/- 4.8 to 46.4 +/- 7.0 mm Hg (p < 0.001); while daytime Pa(O2) increased by 5.8 +/- 9.4 (95% confidence interval, 2.3 to 9.3), from 51.7 +/- 8.8 to 57.5 +/- 9.3 mm Hg (p = 0.002); and FEV1 increased by 0.14 +/- 0.16 (95% confidence interval, 0.08 to 0.20), from 1.03 +/- 0.54 to 1.17 +/- 0.59 L (p < 0.001) after 2 months of NPPV. This was achieved with mean inspiratory pressures of 27.7 +/- 5.9 cm H2O (range, 17 to 40 cm H2O) at a mean respiratory rate of 20.8 +/- 2.5 breaths/min (range, 14 to 24 breaths/min). The 2-year survival rate was 86%. CONCLUSIONS: Controlled NPPV using a mean inspiratory pressure of 28 cm H2O is well tolerated over longer periods and can improve blood gas levels and lung function. Prospective, randomized controlled trials of high-intensity NPPV are required to evaluate its role in patients with stable hypercapnic COPD.

Adult↗