Spontaneous-timed versus controlled noninvasive ventilation in chronic hypercapnia - a crossover trial.

Background: There is an ongoing debate about optimal ventilator modes and settings during noninvasive ventilation (NIV). Objectives: To compare the effect of spontaneous-timed (ST) and controlled NIV on carbon dioxide reduction in patients suffering from chronic hypercapnia. Methods: Night and daytime blood gas analysis, lung function tests and 6 minute walking distance tests (6MWD) were done before and after every 6-week treatment. Results: This randomized prospective crossover trial included 42 patients. Pooled data analysis showed a decrease of nocturnal CO2 from 54.8±5.9 mmHg to 41.6±5.5 mmHg during ST ventilation (p<0.01) and from 56.2±7.5 mmHg to 42.7±5.4 mmHg during controlled NIV (p<0.01) with no difference between treatment forms (p=0.30). Daytime CO2 levels decreased from 49.3±5.5 mmHg to 45.6±4.5 mmHg when spontaneous timed ventilation was applied (p<0.01) and from 52.2±6.8 mmHg to 44.9±21114.4 mmHg in case of controlled ventilation (p<0.01) The amount of CO2 reduction was 3.8±5.6 mmHg after ST mode and 7.3±6.8 mmHg controlled ventilation (p<0.05). Nocturnal ventilator use was 5.7±2.1 and 6.7±2.3 hours for ST and controlled ventilation respectively (p=0.02). There was no effect on walking distance and lung function. Conclusion: Controlled NIV showed improved compliance compared to ST ventilation. We observed similar CO2 reductions during nocturnal ventilation, however controlled ventilation achieved a higher reduction of daytime CO2 levels.

[Early pulmonary rehabilitation after long term mechanical ventilation]. / Pneumologische Frührehabilitation nach Langzeitbeatmung.

BACKGROUND: The term early rehabilitation is defined as a rehabilitation that begins in the early phase after acute illness and is statutory positioned in §â€Š39SGB V. Aim of this investigation is to describe the quality of outcome of pulmonary early rehabilitation. METHOD: Prospective census of functional parameters, status of ventilation and discharge-disposition in a specialized unit for early pulmonary rehabilitation over a period of one year. RESULTS: Out of 190 patients 179 (94.2 %) were previously invasively ventilated. During the treatment period of 39 ±â€Š17 days, FAM-Index increased from 84.4 ±â€Š19.8 to 118.5 ±â€Š23.3 (Ci 30.9 - 37.3, Cohen'd 1.58; p < 0.001), Barthel-Index from 30.5 ±â€Š13.8 to 58.3 ±â€Š16.2 (Ci 25.4 - 33.8, Cohen's d 1.4; p < 0.001) six minute walking distance from 12.9 ±â€Š40.1 m to 131.4 ±â€Š85.2 m (Ci 105.6 - 131.4 m, Cohn's d 1.78; p < 0.001). Patients were less likely to be receive further post-discharge rehabilitation if they were ventilated. CONCLUSION: Patients admitted to the early pulmonary rehabilitation unit were severely compromised, however quality of outcome was favourable and independent of the breathing status (spontaneously breathing vs. non-invasive ventilation or invasive ventilation). Finding discharge dispositions appeared to be more difficult if patients were ventilated.

In vitro validation of a Respimat® adapter for delivery of inhaled bronchodilators during mechanical ventilation.

BACKGROUND: Inhaled bronchodilators are frequently used in patients with chronic obstructive pulmonary disease (COPD). However, there has been no efficient way to administer the long-acting anticholinergic tiotropium to mechanically ventilated patients. The aim of this in vitro study was to compare the fine particle dose (FPD) output of a specifically designed adapter with other accessory devices for the delivery of bronchodilators using the Respimat® (RMT) inhaler by simulating the specific inhalation flow profiles of patients with COPD. METHODS: Using characteristic flow profiles from COPD patients being weaned off mechanical ventilation, an in vitro study was performed analyzing the FPD achieved with different accessory devices (connectors, spacers, AeroTrachPlus valved holding chamber), which can be used to deliver drugs from pressurized metered dose inhalers (pMDI) and RMT inhalers to artificial airways. Fenoterol pMDI, tiotropium RMT, and a fixed-dose combination of salbutamol and ipratropium delivered by pMDI or RMT, were used as bronchodilators. Aerosols were collected by a next-generation impactor. RESULTS: The RMT inhaler, combined with a new in-line adapter, was superior to other inhaler device connector or spacer combinations in FPD delivery during simulated mechanical ventilation (p<0.01). The outcome with the RMT inhaler/RMT adapter combination during simulation of mechanical ventilation was comparable to the measurements with the RMT/AeroTrachPlus valved holding chamber during simulation of spontaneous breathing. The delivery rates of the RMT adapter were not significantly affected by the administered bronchodilators or by the type of artificial airway (endotracheal or tracheostomy tube) employed. CONCLUSIONS: The RMT inhaler combined with the prototype in-line adapter was better than the other accessory device combinations in fine particle deposition of inhaled bronchodilators during mechanical ventilation. Further research is required to determine the clinical relevance of these in vitro findings.