[Can mesh nebulizers improve prehospital aerosol therapy? An in vitro study on simulated prehospital emergency patients suffering from respiratory distress].

BACKGROUND

Nebulizers used to treat prehospital emergency patients should provide a high output efficiency to achieve a fast onset of therapeutic drug effects while remaining unaffected by the presence of supplementary oxygen flow or the patient's breathing pattern. On the other hand, nebulizer performance is directly influenced by differences in device design, gas flow and patients' breathing patterns. Several studies from emergency departments were able to demonstrate an improvement in patient outcome when using a mesh nebulizer instead of a jet nebulizer. Data or bench studies regarding prehospital care are non-existent.

OBJECTIVE

The aim of the present in vitro study was to evaluate which type of aerosol generator would best address the requirements of a prehospital adult emergency patient suffering from respiratory distress.

MATERIAL AND METHODS

We evaluated the performance of a jet nebulizer (Cirrus™ 2, Intersurgical®) and two mesh nebulizers (Aerogen Solo® with USB controller, Aerogen Limited and M‑Neb® mobile, NEBU-TEC International med. Produkte Eike Kern GmbH) with the possibility of portable operation in an in vitro model of a spontaneously breathing adult emergency patient. One physiological and three pathological breathing patterns (distressed breathing pattern as well as stable and acute exacerbated chronic obstructive pulmonary disease) were simulated. Nebulizer output and salbutamol lung deposition were measured at different oxygen flow rates using a face mask as the delivery interface.

RESULTS

The mesh nebulizers produced a significantly higher aerosol output when compared to the jet nebulizer. The M‑Neb® mobile was able to significantly exceed the output of the Aerogen Solo®. Oxygen flow had the largest influence on the output of the jet nebulizer but hardly affected the mesh nebulizers. After a nebulization time of 10 min the M‑Neb® mobile also achieved the highest total salbutamol lung deposition (P < 0.001). Aerosol drug deposition was therefore mainly determined by the nebulizer's drug output per unit time. The deposition could not be improved using a spacer but was strongly influenced by the simulated emergency patients' breathing pattern.

CONCLUSION

The use of mesh nebulizers might have the potential to improve the aerosol therapy of prehospital emergency patients. In general, mesh nebulizers seem to be superior to jet nebulizers regarding aerosol output per unit time and total lung deposition. The present data suggest that aerosol output and drug deposition to the collection filter in this simulated setting are closely connected and crucial for total salbutamol deposition, as the deposition could not be improved by adding a spacer. Aerosol drug deposition in simulated emergency patients' lungs is therefore mainly determined by the nebulizer's drug output per unit time. The level of oxygen flow used had the largest influence on the output of the jet nebulizer but hardly affected the output of the tested mesh nebulizers. Mesh nebulizers could therefore enable a demand-adapted oxygen therapy due to their consistent performance despite the presence of oxygen flow. A high respiratory rate was associated with a high drug deposition, which is clinically desirable in the treatment of patients in respiratory distress; however, drug underdosing must also be expected in the treatment of bradypneic patients. Further clinical studies must prove whether our findings also apply to the treatment of real prehospital emergency patients.

ZUSAMMENFASSUNG

HINTERGRUND: Medikamentenvernebler im Rettungsdienst sollten eine hohe Vernebelungsleistung haben, um schnell eine therapeutische Wirkstoffkonzentration des vernebelten Medikaments zu erreichen. Eine Umfrage im süddeutschen Rettungsdienst zeigte allerdings, dass fast ausschließlich die wenig effizienten Jet-Vernebler zum Einsatz kommen.

ZIEL DER ARBEIT

Ziel der vorliegenden In-vitro-Studie war es herauszufinden, ob der Einsatz von Mesh-Verneblern die prähospitale Aerosoltherapie verbessern könnte.

MATERIAL UND METHODEN

Die Vernebelungsleistung eines Jet-Verneblers (Cirrus™ 2, Fa. Intersurgical®) und 2 mobil einsatzbarer Mesh-Vernebler (Aerogen Solo®, Fa. Aerogen Limited, M‑Neb® mobile, NEBU-TEC International med. Produkte Eike Kern GmbH) wurde in einem In-vitro-Modell spontan atmender Notfallpatient*innen mit 4 unterschiedlichen Atemmustern bei verschiedenen Sauerstoffflussraten getestet.

ERGEBNISSE

Die Mesh-Vernebler zeigten im Vergleich zum Jet-Vernebler eine signifikant höhere Verneblungsleistung und Salbutamol-Filterdeposition, wobei der M‑Neb® mobile die höchsten Werte für Leistung und Deposition erreichte. Der Sauerstofffluss hatte den größten Einfluss auf die Leistung des Jet-Verneblers, wirkte sich aber kaum auf die Mesh-Vernebler aus. Die Deposition wurde zudem stark vom Atemmuster beeinflusst.

DISKUSSION

Der Einsatz von Mesh-Verneblern mit hoher Verneblungsleistung konnte in einem In-vitro-Modell die Aerosoltherapie von prähospitalen Notfallpatient*innen verbessern. Sie waren dem Jet-Vernebler in Bezug auf die Verneblungsleistung und die Lungendeposition überlegen und ermöglichten zudem eine bedarfsangepasste Sauerstofftherapie. Die höchste Medikamentendeposition wurde bei den tachypnoischen Patient*innen erreicht, welche in der praktischen Anwendung auch am meisten von einem erhöhten Medikamentenspiegel profitieren würden.

Informations de copyright

© 2022. The Author(s).