Methods: A breath simulator was set to preterm infant settings (V_T: 9 ml, RR: 50 bpm and Ti: 0.5 sec) and connected to the trachea of an anatomical upper airway model of a preterm infant (DiBlasi) via collecting filter distal to the trachea. The HFNC (Fisher & Paykel), Bubble CPAP (Fisher & Paykel), and SiPAP (Carefusion) were attached to the model via their proprietary nasal cannula and set to deliver 5 cm H₂O pressure. Albuterol sulfate (2.5 mg/0.5 mL) was aerosolized with a mesh nebulizer (Aeroneb Solo) positioned (1) proximal to the patient and (2) prior to the humidifier (n=5).The drug was eluted from the filter with 0.1 N HCl and analyzed via spectrophotometry (276 nm). Data were analyzed using descriptive statistics, t-tests, and analysis of variance (ANOVA), with p

Results: At position 1, the trend of lower deposition across devices was not significant; however, in position 2, drug delivery with SiPAP was significantly lower compared to both HFNC (p=0.003) and bubble CPAP (p=0.008).Placement of the nebulizer prior to the humidifier increased deposition with all devices (p<0.05).

Conclusion: Aerosol can be delivered via all three devices used in this study; however, delivery efficiency of HFNC is better than the other CPAP devices tested. Device selection and nebulizer position impacted aerosol delivery in this simulated model of a spontaneously breathing preterm infant.

Methods: Delivery efficiencies during spontaneous breathing with assisted and unassisted administration techniques were compared using the jet nebulizer (JN- MicroMist), vibrating mesh nebulizer (VMN- Aeroneb Solo) and pressurized metered-dose inhaler (pMDI- ProAirHFA). The direct administration of aerosols in spontaneously breathing patients (unassisted technique) was compared to administration of aerosol therapy via a manual resuscitation bag (assisted technique) attached to the aerosol delivery device and synchronized with inspiration. An in-vitro lung model consisted of an uncuffed tracheostomy tube (4.5 mmID) was attached to a collecting filter (Respirgard) which was connected to a dual-chamber test lung (TTL) and a ventilator (Hamilton). The breathing parameters of a 2 years-old child were set at an RR of 25 breaths/min, a Vt of 150 mL, a Ti of 0.8 sec and PIF of 20 L/min. Albuterol sulfate was administered with each nebulizer (2.5 mg/3 ml) and pMDI with spacer (4 puffs, 108 µg/puff). Each aerosol device was tested five times with both administration techniques (n=5). Drug collected on the filter was eluted with 0.1 N HCl and analyzed via spectrophotometry.

Results: The amount of aerosol deposited in the filter was quantified and expressed as inhaled mass and inhaled mass percent. The pMDI with spacer had the highest inhaled mass percent, while the VMN had the highest inhaled mass. The results of this study also found that JN had the least efficient aerosol device used in this study. The trend of higher deposition with unassisted versus assisted administration of aerosol was not significant (p>0.05).

Conclusions: Drug deposited distal to the tracheostomy tube with JN was lesser than either VMN or pMDI. Delivery efficiency was similar with unassisted and assisted aerosol administration technique in this in vitro pediatric model.

Methods: Each aerosol generator was placed between manual resuscitator bag (Ambu SPUR II Disposable Resuscitator, Ambu Inc, Glen Burnie, MD) and infant facemask (Mercury Medical, Cleanwater, FL), which was held tightly against the SAINT model. Breathing parameters used in this study were Vt of 100 mL, RR of 30 breaths/min, and I:E ratio of 1: 1.4. Active and passive breathing patterns were used in this study with aerosol device; active breathing pattern was created using a ventilator (Esprit Ventilator, Respironics/Philips Healthcare, Murrysville, PA) connected to a dual chamber test lung (Michigan Instruments, Grand Rapids, MI), which was attached to an absolute filter (Respirgard II, Vital Signs Colorado Inc, Englewood, CO), to collect aerosolized drug, connected to the SAINT model. Pediatric resuscitator bag was run at 10 L/min of oxygen and attached to aerosol generator with facemask. In passive breathing pattern, SAINT model was attached to test lung and ventilated using the resuscitator bag with the same breathing parameters. Each aerosol device was tested three times (n=3) with each breathing patterns. Drug was eluted from the filter and analyzed using spectrophotometry. The amount of drug deposited on the filter was quantified and expressed as a percentage of the total drug dose. To measure the differences in the inhaled drug mass between JN, VMN, and pMDI/VHC in active or passive breathing, one-way analysis of variance (one-way ANOVA) was performed. To quantify the difference in aerosol depositions between the two breathing patterns, independent t-test was performed. A p < 0.05 was considered to be statistically significant.

Results: Although the amount of aerosol deposition with the JN was the same in passive and active breathing without any significant difference, the VMN was more efficient in active breathing than the JN (p = 0.157 and p = 0.729, respectively). pMDI/VHC had the greatest deposition in the simulated spontaneous breathing (p=0.013)

Conclusion: Aerosol treatment may be administered to young children using JN, VMN, or pMDI/VHC combined with resuscitator bag. Using pMDI/VHC with resuscitator bag is the best choice to deliver albuterol in spontaneously breathing children. Further studies are needed to determine the effectiveness of these aerosol generators with different type of resuscitator bag and different breathing parameters.

Methodology: The SAINT model, attached to an absolute filter (Respirgard II, Vital Signs Colorado Inc., Englewood, CO, USA) for aerosol collection, was connected to a pediatric breathing simulator (Harvard Apparatus, Model 613, South Natick, MA, USA). To keep the filter and the SAINT model in upright position to collect aerosolized drug, an elbow adapter was connected between the absolute filter and the breathing simulator. An infant HFNC (Optiflow, Fisher & Paykel Healthcare LTD., Auckland, New Zealand) ran at 3 l/min O₂ was attached to the nares of the SAINT model. Breathing parameters used in this study were Vt of 100 mL, RR of 30 breaths/min, and I:E ratio of 1: 1.4. Aerosol drug was administered using: 1) Misty-neb jet nebulizer (Allegiance Healthcare, McGaw Park, Illinois, USA) powered by air at 8 l/min using pediatric aerosol facemask (B&F Medical, Allied Healthcare Products, Saint Louis, MO, USA) to deliver albuterol sulfate (2.5 mg/3 mL NS), and 2) Four actuations of Ventolin HFA pMDI (90 μg/puff) (GlaxoSmithKline, Research Triangle Park, NC, USA) combined with VHC (AeroChamber plus with Flow-Vu, Monaghan Medical, Plattsburgh, NY, USA). Aerosol was administered to the model with and without the HFNC and another without (n=3). Drug was collected on an absolute filter, eluted and measured using spectrophotometry. Independent t tests were performed for data analysis. Statistical significance was determined with a p value of <0.05.

Results: The mean inhaled mass percent was greatest for pMDI with (p = 0.0001) or without HFNC (p = 0.003). Removing HFNC from the nares before aerosol treatment trended to increase drug delivery with the jet nebulizer (p = 0.024), and increased drug delivery by 6 fold with pMDI (p = 0.003).

Conclusions: Aerosol drug may be administered in pediatrics receiving HFNC therapy using either jet nebulizer or pMDI. However, using pMDI, either with or without HFNC, is the best option. When delivering medical aerosol by mask, whether by jet nebulizer or pMDI, removing HFNC led to an increase in inhaled mass percent. However, the benefit of increased aerosol delivery must be weighed against the risk of lung derecruitment when nasal prongs are removed.

BACKGROUND: Although Problem-based learning (PBL) approach is a common teaching technique in medical education, its use in the field of respiratory therapy is somewhat controversial. With so many programs adopting PBL strategies, it is important to examine whether there are differences between PBL and traditional teaching approaches in regards to learning outcomes. Therefore, the purpose of this study was to investigate if there are any significant differences between PBL and lecture-based program students in their cognitive abilities in mechanical ventilation.

METHODS: Two universities with BS programs in respiratory therapy were chosen—one uses PBL (15 participants) and on uses lecture-based method (24 participants). All 39 participants were given10 multiple-choice questions related to mechanical ventilation derived from the NBRC RRT written exam forms (C & D) as a pre and a post test.

RESULTS: The dependent t-test showed a significant difference between the pre and post test of the lecture-based and the PBL groups, resulting in a p value of 0.006 and 0.025 respectively. The independent t-test showed a significant difference in the pre-test favoring the lecture-based group (p = 0.039). However, the independent t-test showed no significant difference in the post-test (p=0.085)

CONCLUSIONS: PBL is increasing in popularity despite the fact that studies of its efficacy have been thus far inconclusive. This study has shown PBL to be effective, but not significantly more effective than traditional lecture-based methods in regards to objective test scores.

Methods: An in-vitro lung model consisting of an 8.0 mm ID endotracheal tube (ETT) connected to a standard ventilator circuit and ventilator was connected to a rubber test lung via cascade humidifier set to deliver 37˚C and 100% relative humidity. The ventilator settings were as follows: Vt 450 ml, RR 20/min, PIF 50 L/min, PEEP 5 cm H2O, and I:E ratio 1:2. HME-ADs used in this study include Circuvent HME/HCH bypass (Smiths-Medical, Keene, NH), Gibeck Humid-Flo HME (Hudson RCI, Arlington Heights, IL), and Airlife BHME (Carefusion, San Diego, CA). As a control, albuterol sulfate (2.5 mg/3mL) was delivered with a vibrating mesh nebulizer (Aeroneb Solo, Aerogen Inc) placed at the wye without any HME-AD in the circuit. Then, the aerosol and HME configurations of each HME-AD were tested by measuring pre-post Raw and aerosol deposition at the end of each run. Each condition was repeated in triplicate (n=3). Aerosol deposition between the aerosol and HME configurations of each HME-AD was compared with a series of student t-tests. Then, differences both in aerosol deposition and in airway resistance among the HME-ADs were analyzed using one-way analysis of variance (ANOVA). Significance was determined as p<0.05.

Results: Raw increased after each albuterol treatment with every HME-AD. In the aerosol configuration, the Circuvent and Humid-Flo delivered significantly less aerosol compared to the control (p=.004 and p=.002, respectively), while there was no significant difference on aerosol delivery between the Airlife and the control (p=.084). The Airlife gave the highest aerosol deposition which was not significantly different than control (p=.084). When aerosol delivery between the HME and aerosol configurations in each HME-AD was compared, aerosol deposition with the Humid-Flo was not significantly different (p=.078) but both the Airlife and the Circuvent showed a statistically significant reduction in aerosol deposition with the HME configuration (p=.002 and p=.005).

Conclusions: Aerosol delivery and Raw with each HME-AD differ in simulated mechanically ventilated patients. Further studies are needed to determine the effectiveness of these devices over time and with different aerosol generating devices.

Methods: A teaching mannequin (Medical Plastic Labs, Gatesville, TX) with a tracheostomy opening was used. Two of the mannequin's bronchi were connected to a "Y" adaptor, which was attached to a collecting filter (Respirgard ™ II 303, Vital Signs, Englewood, CO), which was connected to a breathing simulator (Harvard Apparatus Dual Phase Control Respirator Pump, Holliston, MA) through a corrugated tube. Settings for spontaneous breathing were respiratory rate 20/min, and tidal volume 400 mL. The I:E ratios were adjusted in the first and second comparisons at 2:1 and 1:2, respectively. The nebulizer was operated by a flow meter (Timemeter, St. Louis, MO) at 8 L/min with 100% oxygen. In every condition, the flow was discontinued at the end of nebulization. The nebulizer was attached to the tracheostomy collar (AirLife™, Cardinal Health, McGaw Park, IL) in the first group, the Wright mask (Wright Solutions LLC, Marathon, FL) in the second group, and the aerosol mask (AirLife™, Cardinal Health, McGaw, IL) in the third group. Drug was eluted from the filter and analyzed by spectrophotometry (276 nm).

Data Analysis: Paired t-test, one-way analysis of variance (ANOVA), repeated measures ANOVA, post-hoc and pairwise comparisons were performed at the significance level of .05, using PASW version 18.0.

Results: Aerosol delivery was greater with the tracheostomy collar than the Wright mask and aerosol mask (p < .05). Closing the fenestration hole increased aerosol deposition significantly at 2:1 ratio (p = .04) compared to opening the fenestration at 1:2 ratio. I:E ratio and aerosol delivery were directly related. Increasing I:E ratio from 1:2 to 2:1 improved aerosol delivery significantly with tracheostomy collar-fenestration opened (p = .009), Wright mask (p = .02) and aerosol mask (p = .01).

Conclusion: This study indicates that the use of a tracheostomy collar is the best method of delivering aerosol therapy among the three interfaces. The I:E ratio of 2:1 caused greater aerosol deposition than 1:2 ratio. The aerosol deposition was better when the fenestration hole was closed compared with opened fenestration.

METHODS: We connected each aerosol generator—JN, BAN, or pMDI with a valved holding chamber (VHC)—to the face of an adult teaching manikin. Below the bifurcation, an elbow adaptor was connected to a corrugated tube and was angled to be at a lower level than the collecting filter to prevent droplets from dripping directly into the collecting filter. From the collecting filter, another corrugated tube was connected to a prevention filter, which was then connected to an adult breathing simulator. Spontaneous breathing parameters were V_T 450 mL, RR 20/min, and I: E ratio 1:2. First, we compared JN, BAN (2.5 mg/3 mL), and pMDI (4 puffs); second, we compared JN and BAN 2.5 mg/0.5 mL plus 0.5 mL normal saline. Data were analyzed using spectrophotometry (276 nm). One-way ANOVA and independent sample t-tests were used (p<0.05).

RESULTS: There were no differences in inhaled mass percentage (p=0.172) JN, BAN, and pMDI in the first experiment. Treatment time with BAN was significantly longer (p=0.0001) than with JN or pMDI. In the second experiment, BAN delivered more medication (p=0.004) than jet nebulizer. Treatment time was significantly less with JN (p=0.010). There was no difference in residual volume among JN and BAN in both experiment (p=0.765, p=0.115).

CONCLUSIONS: All the devices that were compared using a 3 ml or 4 pMDI puffs delivered comparable amount of medication with no significant difference. However, BAN using 1ml fill volume delivers more drug compared to JN. Additionally, treatment time was longest with BAN. Even with reduction of its filling volume, BAN delivers a higher amount of medication to that of pMDI but was not statistically significant.

Purpose: The study was on an in vitro bench model that answered the following researchquestions: 1. The effect of three inline closed suction adapters on delivered tidal volume duringHFOV with varying lung compliance 2. The effect of varying compliance on the amplitudedelivered by HFOV; and 3. The effect of compliance on tidal volume delivered by HFOV.

Method: An in vitro bench model using high fidelity breathing simulator (ASL 5000, IngMarMedical) simulating an adult patient with ARDS was set up with 3100B SensorMedic highfrequency ventilator. The simulation included varying the compliance for each lung at 50, 40, 30and 20cmH2O while maintaining fixed resistance of 15 cmH2O/L/sec. The ventilator was set tothe following parameters: power of 6, frequency (f) of 5, inspiratory time (Ti) of 33%, bias flow(BF) of 30 LPM and oxygen concentration of 50%. The breathing simulator was connected withthe high frequency ventilator using a standard HFOV circuit and a size 8.0mm of endotrachealtube. Fourteen French Kimberly Clark suction catheters (with T and Elbow adapters) and Air-Life suction catheters (Y adapter) were placed in-line with the circuit successively to carry outthe study. Each run lasted for 1 minute after achieving stable state conditions. Thisapproximated to 300 breaths. The data was collected from the stimulator and stored by the hostcomputer.

Data Analysis: The data was analyzed using SPSS v.11 to determine the statistical significance.A probability value (P value) of ≤ 0.001 was considered to be statistically significant.

Results: The data analysis showed that Air-Life Y-adapter suction catheters caused the least lostin tidal volume when placed in line with HFOV and hence proved to be the most efficient. Thestudy also showed a direct relationship between amplitude and lung compliance i.e. an increasein lung compliance caused an associated increase in amplitude (power setting remainingunaltered). Lastly, the study did not show a statistically significant change in tidal volume withchanges in lung compliance. Future studies may be required to further evaluate the clinicalsignificance of the same.

Conclusion:1. Many factors affect delivery of tidal volume during high frequency ventilation and thus it isnot constant. Choice of in-line suction system to be placed in line is one of the determinants ofthe same.2. Lung compliance changes lead to associated changes in amplitude delivery by HFOV. Thisshould be adjusted as patient condition improves by altering the power settings to ensure optimalventilation and to avoid trauma to the lungs.

Method: An in vitro lung model consisted of the upper airway of an adult teaching manikin with a collecting filter at the level of the bronchi attached to a passive test lung. NIPPV was administered via full face mask for the first experiment (AF531 oro-nasal) with an IPAP/EPAP of 20/5 cm H₂O and a respiratory rate of 15 Breath per minute (BPM). Aerosol generators were placed between the leak in the circuit and the mask. Albuterol sulfate (2.5 mg/ 3 ml) was nebulized with the JN (Micromist) and the VMN (Aeroneb Solo). Four puffs (108 µg/puff) were administered with the pMDI (ProAir HFA) with a spacer (Aerovent) that first was placed in the recommended normal position (pMDI-N) with aerosol plume directed towards patient, and then in the reversed position (pMDI-R), with aerosol directed away from patient (n=3). In the second experiment, three masks were used 1) the Performax mask, 2) the AF531 oro-nasal mask, and 3) the Performa track mask. Performa track mask was tested with only Aeroneb solo while other masks were tested with both Aeroneb solo and NIVO VMNs. In both experiments, filters were eluted with 0.1 HCl and analyzed by a spectrophotometer at 276 nm. Residual volumes were determined gravimetrically.

Result: Descriptive statistics, one-way analysis of variance (ANOVA), and independent t tests were used. Statistical significance was set at p<0.05. During NIPPV, inhaled mass (IM) and inhaled mass percent (IM %) varied significantly (p=0.042 and p=0.028, respectively). Aerosol delivery with the JN was the lowest during NIPPV. The VMN has a significantly lower residual volume than the JN (p=0.0001). No statistical difference in efficiency was found between the two pMDI orientations (p=0.253). In the second experiment, oro nasal mask with Aeroneb Solo VMN results in the highest IM which was significant when compared with all other masks(p=0.0001). No statistical difference can be found between other masks.

Conclusion: The JN was less efficient than the VMN and the pMDI in either orientation. The type of aerosol device used during NIPPV influenced aerosol delivery in this simulated adult lung model. Oro nasal mask with Aeroneb Solo VMN provided the highest IM.