In vitro investigation of the Flusso™ Bypass adapter efficiency upon ventilator circuit disconnect in a clinical simulated environment.

RATIONALE: Mechanically ventilated patients must be disconnected from the ventilator during intra-facility transfers. Intentional and accidental circuit disconnections represent a potential hazard to patients (sudden collapse and re-expansion of the alveoli) as well as to clinical staff (exposure to patient's unfiltered exhalation). Therefore, avoiding abrupt circuit disconnections could better protect the patient's health and reduce or eliminate contamination risks around clinical staff. OBJECTIVE: The purpose of this in-vitro work was to investigate and evaluate the potential for environmental exposure of Nitric Oxide (NO, as an indicator of any contamination exposure) before and after implementing the novel Flusso™ Bypass adapter during the disconnect procedure of a mechanical ventilator system. METHODS: A mechanical ventilator delivering NO was connected to a breathing simulator with and without the Flusso™ Bypass adapter. The ambient NO concentration was measured when the circuit was briefly disconnected (3 s) during inhalation and exhalation. Both volume and pressure ventilation modes were used. MEASUREMENTS AND MAIN RESULTS: Disconnecting the standard ventilator circuit (pressure-controlled mode) without the Flusso™ Bypass adapter produced higher NO escape to the surroundings (compared with the volume-controlled mode), leading to a longer NO dissipation time. No ambient NO traces were detected when the Flusso™ adapter was used. CONCLUSION: The usage of the Flusso™ adapter drastically decreases the unwanted exposure among clinical staff dealing with potentially hazardous airborne biological aerosols emanating from the circuit. Avoiding abrupt disconnection in the ventilator circuit could reduce lung injuries and alveolar over distension and collapse.

In Vitro Measurements of Spiriva Respimat Dose Delivery in Mechanically Ventilated Tracheostomy Patients.

Background: For patients with severe chronic obstructive pulmonary disease under invasive mechanical ventilation, medication for aerosol therapy is delivered through tracheostomy or endotracheal airways. Typically, these medications (such as bronchodilators) are long-acting formulations that are delivered through Soft Mist™ Inhalers (SMI), or Pressurized Metered-Dose Inhalers. The Respimat® SMI has been shown to have increased efficiency because of its slow and prolonged aerosol mist and has gained popularity in clinical settings. However, the Respimat was not designed for drug delivery through artificial airways. Therefore, there is a need for SMI adapters in intensive care for use in mechanical ventilator circuits. The purpose of this study was to evaluate the performance of a new Respimat adapter (ODAPT™ for mechanical ventilator [ODAPT MV]) for use in mechanical ventilator circuits which, in combination with a Pulmodyne T-piece adapter, allows use without interruption of the circuit in case of medication replacement. Methods: Tiotropium delivery to the lungs, using Respimat, was assessed using the ODAPT MV adapter within an in vitro setup, including a three-dimensional printed trachea model and a mechanical ventilator. Medication deposition and losses were investigated using two commonly used tracheostomy tube (TT) sizes (6 and 8 mm inner canula) for two flow rates (45 and 60 L/min) under different conditions (30%-50%. and 100% relative humidity [RH]). Medication delivery using the ODAPT MV adapter was compared with the RTC-26C in-line adapter under similar conditions (8 mm TT size, 100% RH at 45 L/min). Results: It was found that 7.1%-13.4% of the nominal dose (ND) was lost in the ODAPT MV adapter for different TT size, RH, and flow rates used. Higher losses were found in the inhaler's mouthpiece ranging from 15.7% to 29.1% ND. The percentage of the delivered medication reaching the lungs was determined to be 13.7%-18.5% ND delivered without significant differences between the experimental conditions tested. The ODAPT MV performed well compared with the RTC-26C under similar conditions (17.9% and 16.6% ND, respectively). Conclusion: The medication delivered through mechanical ventilation using the ODAPT MV adapter represents about one third the dose delivered directly through the Respimat SMI in vivo.

Experimental Study of Spiriva Respimat Soft Mist Inhaler Spray Characterization: Size Distributions and Velocity.

Background: Respiratory illnesses such as asthma, bronchitis, and chronic obstructive pulmonary disease (COPD) are considered to be debilitating diseases. A variety of inhalation devices have been used to deliver aerosol medication to patients in the treatment of those diseases. Soft Mist Inhalers (SMIs, for example, the Spiriva Respimat) are a new generation of propellant-free inhalers. In this type of inhalation device, inhalable droplets are generated from an aqueous solution. Droplet size and velocity are two of the most substantial factors that impact the deposition of SMI aerosol medication into the patient lungs. Methods: In this study, size and velocity of droplets generated from the Spiriva Respimat inhaler were measured using phase Doppler anemometry (PDA). Measurements were taken at four locations along the centerline of the Spiriva Respimat inhaler, in addition to three cross sections (free-spray configuration). In addition, measurements were also performed at a single cross section in confined spray configurations using two separate idealized mouth cavities. Results and Conclusions: Measurements along the centerline of the aerosol mist generated using the Spiriva Respimat inhaler (6.5, 25, 100, and 125 mm downstream of the inhaler nozzle' orifice) showed that droplets at the mouthpiece have the highest velocity of 10.95 m/s, decreasing to 1.33 m/s at the 125 mm location away from the nozzle. The mean diameter D10 values ranged from 3.97 to 3.67 µm at 6.5 and 125 mm locations, respectively. In addition, of the three probability density functions (PDFs) that were tested, the log-normal PDF showed better curve fitting for the empirical data (droplet size distributions) that were measured. The effect of spray confinement using two idealized mouth cavities shows that there was a drop in the particles' velocity for both models on each axes compared with the open-air environment (free-spray configuration).