Respiratory Care

The Flutter VRP1 device is used for airway clearance. Its performance is based on 4 basic effects: positive expiratory pressure (PEP), forced exhalations (huff), high-frequency airway flow oscillation, and modification of mucus viscoelasticity. The purpose of this study was to determine the flow and angle conditions in which these effects are optimized.

In an experimental setting, a Flutter VRP1 was fixed at angles of −30°, −15°, 0°, +15°, and +30°, and submitted to flows ranging from 0.2 L/s to 2.0 L/s. The flows and angles that resulted in higher and lower values of mean pressure, mean flow, oscillation frequency, and flow amplitude were determined. In addition, it was defined which angles facilitated achieving “ideal” mean pressure of 10 cm H₂O and 20 cm H₂O and oscillation frequency of 12 Hz.

At all flows, +15° produced higher mean pressure (p < 0.01), whereas lower values were produced at −30° at lower flows, 0° at intermediate flows, and +30° at higher flows (p < 0.01). Higher oscillation frequencies were produced at +30° and +15° (p < 0.01), and lower values were produced at −30° and −15° at all flows (p < 0.01). Higher flow-amplitude values were produced at +30°, +15°, and 0° (p < 0.01), and lower values were produced at −30° and −15° (p < 0.01). Mean pressure of 10 cm H₂O was reached with the lowest flow (0.2 L/s) at +30°, and mean pressure of 20 cm H₂O was produced at +15° (1.0 L/s), whereas an oscillation frequency of 12 Hz was reached at 0°, +30°, and +15°, at 0.2 L/s.

Positive inclinations optimize positive expiratory pressure and flow-amplitude effects, whereas negative inclinations optimize huff effect. This theoretical knowledge may help optimize the use of the device when applied to different conditions.

Handling of inhaler devices such as pressurized metered-dose inhalers (MDIs) and dry-powder inhalers (DPIs) in actual pulmonary practice is not well studied.

The aim of this study was to evaluate patients' proper handling of inhaler devices during actual pulmonary practice.

Prospective observational evaluations were conducted at 3 pulmonary clinics in Jordan, from February 2006 until August 2006. MDI (without spacer), Turbuhaler, Diskus, and Aerolizer devices were studied. Incorrect handling was defined as improper technique in any of the predefined essential steps.

Patients (n = 300) were recruited and 525 inhaler-device handling technique evaluations were completed. Diskus inhaler had the lowest rate of incorrect handling (7/103, 6.8%) and MDI had the highest rate of incorrect handling (144/193, 74.6%). Turbuhaler and Aerolizer were handled incorrectly by 63/146 (43.2%) and 14/83 (16.9%) patients, respectively. DPI had a lower rate of incorrect handling, when compared with the MDI (p < 0.001). Among the DPI devices, the Diskus had the lowest rate of incorrect handling (p < 0.031).

In actual pulmonary clinical practice the majority of patients were unable to use MDI correctly, whereas correct handling of DPI devices was variable. Regular checking of inhalation technique and proper teaching by health care providers is crucial for optimum use of most inhaler devices.

We designed this study to evaluate the simplicity of the user interface in modern-generation mechanical ventilators. We hypothesized that different designs in the user interface could result in different rates of operational failures.

A laboratory in a tertiary teaching hospital.

Crossover design.

Twenty-one medical resident physicians who did not possess operating experience with any of the selected ventilators.

Four modern mechanical ventilators were selected: Dräger Evita XL, Maquet Servo-i, Newport e500, and Puritan Bennett 840. Each subject was requested to perform 8 tasks on each ventilator. Two objective variables (the number of successfully completed tasks without operational failures and the operational time) and the overall subjective rating of the ease of use, measured with a 100-mm visual analog scale were recorded.

The total percentage of operational failures made for all subjects, for all tasks, was 23%. There were significant differences in the rates of operational failures and operational time among the 4 ventilators. Subjects made more operational failures in setting up the ventilators and in making ventilator-setting changes than in reacting to alarms. The subjective feeling of the ease of use was also significantly different among the ventilators.

The design of the user interface is relevant to the occurrence of operational failures. Our data indicate that ventilator designers could optimize the user-interface design to reduce the operational failures; therefore, basic user interface should be standardized among the clinically used mechanical ventilators.

Metered-dose inhalers with valved holding chambers (MDI-VHCs) have been shown to be equivalent to small-volume nebulizers (SVNs) for the delivery of bronchodilators in children. At Seattle Children's Hospital and Regional Medical Center we sought to implement the conversion from SVN to MDI-delivered albuterol in nonintubated patients receiving intermittent treatments.

There were 4 distinct interventions used to plan and implement this conversion program: (1) literature review, (2) product selection, (3) policy and operational changes, and (4) staff training. Bronchodilator administration guidelines and clinical pathways for asthma and bronchiolitis were revised to recommend MDI-VHC use in lieu of SVNs. Computerized physician order sets were amended to indicate MDI-VHC as the preferred method of delivering inhaled albuterol in children with asthma and bronchiolitis. Data from administrative case mix files and computerized medication delivery systems were used to assess the impact of our program.

MDI-VHC utilization increased from 25% to 77% among all non-intensive-care patients receiving albuterol, and from 10% to 79% among patients with asthma (p < 0.001). Duration of stay among patients with asthma was unchanged after conversion to MDI-VHC (p = 0.53).

Our program was very successful at promoting the use of MDI-VHC for the administration of albuterol in our pediatric hospital. Duration of stay among patients with asthma did not change during or since the implementation of this program.