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Delivery Efficiency of Albuterol Pressurized Metered Dose Inhaler Through Small Size Laryngeal Mask Airways in an
Ariel Berlinski1, Jessica Fonzie2, L Denise Willis2
1Dr Berlinski is affiliated with Department of Pediatrics, University of Arkansas for Medical Sciences, College of Medicine, Little Rock, Arkansas; Pediatric Aerosol Research Laboratory, Arkansas Children's Research Institute, Little Rock, Arkansas; and Respiratory Care Services, Arkansas Children's Hospital, Little Rock, Arkansas.
Insights
Using a valved holding chamber (VHC) with a metered-dose inhaler (MDI) albuterol during exhalation and a small laryngeal mask airway (LMA) improves drug delivery efficiency in pediatric patients. An adapter device proved inefficient, leading to significant drug deposition in the breathing circuit.
Area of Science:
- Anesthesiology
- Pediatric Critical Care
- Respiratory Medicine
Background:
- Intraoperative bronchospasm in pediatric patients using laryngeal mask airways (LMAs) is often managed with albuterol from a pressurized metered-dose inhaler (pMDI).
- Optimizing albuterol delivery via LMAs is crucial for effective management of bronchospasm in pediatric anesthesia.
Purpose of the Study:
- To evaluate the efficiency of pMDI albuterol delivery through LMAs under various experimental conditions in a pediatric mechanical ventilation model.
- To compare different devices, actuation timings, tidal volumes, actuation modes, and LMA sizes for optimizing aerosolized drug delivery.
Main Methods:
- Albuterol delivery efficiency was assessed using a filter placed between the LMA and a test lung, measuring drug deposition in the circuit (elbow) and LMA.
- Key variables investigated included device type (valved holding chamber [VHC] vs. adapter), actuation timing (inspiration vs. expiration), tidal volumes (50 mL vs. 100 mL), actuation mode (single vs. multiple), and LMA sizes (1, 1.5, 2).
- Multiple regression analysis was employed to determine the contribution of each factor to drug delivery efficiency and circuit/LMA deposition.
Main Results:
- Drug delivery efficiency was significantly higher with a VHC (6.3%) compared to an adapter (0%).
- Circuit deposition was substantially lower with a VHC (2.9%) than with an adapter (25.8%).
- Device type, actuation timing during exhalation, and smaller LMA size were significant factors influencing delivery efficiency.
Conclusions:
- Utilizing a VHC, actuating the pMDI during exhalation, and employing a smaller LMA size enhance albuterol delivery efficiency.
- The adapter is an ineffective device for pMDI albuterol delivery through LMAs, resulting in considerable drug deposition within the breathing circuit.
Abstract:
Background: Intraoperative bronchospasm in pediatric patients supported through laryngeal mask airways (LMAs) is commonly treated with pressurized metered-dose inhaler (pMDI) albuterol. The aim of the study was to evaluate delivery of pMDI albuterol through LMAs under different conditions in a model of infant/child supported with a ventilator. Methods: We compared drug delivery efficiency of 4 actuations of albuterol pMDI (captured on a filter placed between the LMA and a test lung), drug deposition in the circuit (elbow) and in the LMA under different experimental conditions. Outcomes were expressed of percentage of nominal dose. We compared devices (valved holding chamber [VHC] and adapter), timing of administration (inspiration and expiration), tidal volumes (50 mL and 100 mL), mode of actuation (single and multiple), and LMA sizes (1, 1.5, and 2). Multiple regression analysis was used to evaluate the contribution of each to these components to the outcomes. P < .05 was considered statistically significant. Results: Results are expressed as median (interquartile range) of pooled data. Drug delivery efficiency was 0% (0-1.1) and 6.3% (3.2-14.7) for adapter and VHC, respectively. Elbow deposition was 25.8% (19.2-63.3) and 2.9% (1.4-6.4) for adapter and VHC, respectively. LMA deposition was 2.6% (1.3-4.6) and 4.6% (2.9-6.1) for adapter and VHC, respectively. Multiple regression analysis showed that device, timing of actuation, and LMA size explained 33%, 17%, and 8% of the observed variation in delivery efficiency (R2 0.63), respectively. Multiple regression analysis showed that device and timing of actuation explained 52% and 16% of the observed variation, respectively (R2 0.70). Multiple regression analysis poorly explained factors associated with LMA deposition (R2 0.22). Conclusions: Using a VHC, actuating the pMDI during exhalation, and using a small LMA size increased drug delivery efficiency. The adapter was an inefficient add-on device for aerosol delivery with a pMDI through an LMA that caused significant circuit deposition.
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