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A method to assess adherence in inhaler use through analysis of acoustic recordings of inhaler events.

D'Arcy S, MacHale E, Seheult J, Holmes MS, Hughes C, Sulaiman I, Hyland D, O'Reilly C, Glynn S, Al-Zaabi T, McCourt J, Taylor T, Keane F, Killane I, Reilly RB, Costello RW - PLoS ONE (2014)

Bottom Line: The correlation between clinical outcomes and adherence, as determined by this device, was compared for temporal adherence alone and combined temporal and technique adherence.Repeated training reduced this to 7% of participants (p = 0.03).EudraCT 2011-004149-42.

View Article: PubMed Central - PubMed

Affiliation: Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland.

ABSTRACT

Rationale: Poor adherence to inhaler use can be due to poor temporal and/or technique adherence. Up until now there has been no way of reliably tracking both these factors in everyday inhaler use.

Objectives: This paper introduces a device developed to create time stamped acoustic recordings of an individual's inhaler use, in which empirical evidence of temporal and technique adherence in inhaler use can be monitored over time. The correlation between clinical outcomes and adherence, as determined by this device, was compared for temporal adherence alone and combined temporal and technique adherence.

Findings: The technology was validated by showing that the doses taken matched the number of audio recordings (r2 = 0.94, p<0.01). To demonstrate that audio analysis of inhaler use gives objective information, in vitro studies were performed. These showed that acoustic profiles of inhalations correlated with the peak inspiratory flow rate (r2 = 0.97, p<0.01), and that the acoustic energy of exhalations into the inhaler was related to the amount of drug removed. Despite training, 16% of participants exhaled into the mouthpiece after priming, in >20% of their inhaler events. Repeated training reduced this to 7% of participants (p = 0.03). When time of use was considered, there was no evidence of a relationship between adherence and changes in AQLQ (r2 = 0.2) or PEFR (r2 = 0.2). Combining time and technique the rate of adherence was related to changes in AQLQ (r2 = 0.53, p = 0.01) and PEFR (r2 = 0.29, p = 0.01).

Conclusions: This study presents a novel method to objectively assess how errors in both time and technique of inhaler use impact on clinical outcomes.

Trial registration: EudraCT 2011-004149-42.

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The amplitude and corresponding spectrogram of an individual with a weak inhalation is shown in (A).In (B) the amplitude and corresponding spectrogram of another individual with a strong inhalation is shown. In (C) the relationship of the amplitude of inhalation to peak inspiratory flow rate is shown, there is a strong relationship between these two variables, r2 = 0.97. In (D) the relationship of amplitude of inhalation to drug removal is shown.
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pone-0098701-g002: The amplitude and corresponding spectrogram of an individual with a weak inhalation is shown in (A).In (B) the amplitude and corresponding spectrogram of another individual with a strong inhalation is shown. In (C) the relationship of the amplitude of inhalation to peak inspiratory flow rate is shown, there is a strong relationship between these two variables, r2 = 0.97. In (D) the relationship of amplitude of inhalation to drug removal is shown.

Mentions: Studies showed that there was variability in the amplitude of acoustics when individuals inhaled, Figure 2A and B. We quantified the relationship of the acoustics of inhalation with peak inspiratory flow rates and with drug delivery. The technical details of these experiments are presented in “Objective measures of acoustic profile of inhalation and exhalation” in File S1. The amplitude of inhalation was closely related to the inspiratory flow rate, R2 = 0.97, p<0.01 Figure 2C. The amplitude of inhalation was also related to the weight of drug extracted from the inhaler, Figure 2D. This allowed us to objectively assess if there was a critical error in inhalation, if the median amplitude was <0.016AU (corresponding to a flow rate of 30 L/min) then such an event was classed as an inhalation error.


A method to assess adherence in inhaler use through analysis of acoustic recordings of inhaler events.

D'Arcy S, MacHale E, Seheult J, Holmes MS, Hughes C, Sulaiman I, Hyland D, O'Reilly C, Glynn S, Al-Zaabi T, McCourt J, Taylor T, Keane F, Killane I, Reilly RB, Costello RW - PLoS ONE (2014)

The amplitude and corresponding spectrogram of an individual with a weak inhalation is shown in (A).In (B) the amplitude and corresponding spectrogram of another individual with a strong inhalation is shown. In (C) the relationship of the amplitude of inhalation to peak inspiratory flow rate is shown, there is a strong relationship between these two variables, r2 = 0.97. In (D) the relationship of amplitude of inhalation to drug removal is shown.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048229&req=5

pone-0098701-g002: The amplitude and corresponding spectrogram of an individual with a weak inhalation is shown in (A).In (B) the amplitude and corresponding spectrogram of another individual with a strong inhalation is shown. In (C) the relationship of the amplitude of inhalation to peak inspiratory flow rate is shown, there is a strong relationship between these two variables, r2 = 0.97. In (D) the relationship of amplitude of inhalation to drug removal is shown.
Mentions: Studies showed that there was variability in the amplitude of acoustics when individuals inhaled, Figure 2A and B. We quantified the relationship of the acoustics of inhalation with peak inspiratory flow rates and with drug delivery. The technical details of these experiments are presented in “Objective measures of acoustic profile of inhalation and exhalation” in File S1. The amplitude of inhalation was closely related to the inspiratory flow rate, R2 = 0.97, p<0.01 Figure 2C. The amplitude of inhalation was also related to the weight of drug extracted from the inhaler, Figure 2D. This allowed us to objectively assess if there was a critical error in inhalation, if the median amplitude was <0.016AU (corresponding to a flow rate of 30 L/min) then such an event was classed as an inhalation error.

Bottom Line: The correlation between clinical outcomes and adherence, as determined by this device, was compared for temporal adherence alone and combined temporal and technique adherence.Repeated training reduced this to 7% of participants (p = 0.03).EudraCT 2011-004149-42.

View Article: PubMed Central - PubMed

Affiliation: Trinity Centre for Bioengineering, Trinity College Dublin, Dublin, Ireland.

ABSTRACT

Rationale: Poor adherence to inhaler use can be due to poor temporal and/or technique adherence. Up until now there has been no way of reliably tracking both these factors in everyday inhaler use.

Objectives: This paper introduces a device developed to create time stamped acoustic recordings of an individual's inhaler use, in which empirical evidence of temporal and technique adherence in inhaler use can be monitored over time. The correlation between clinical outcomes and adherence, as determined by this device, was compared for temporal adherence alone and combined temporal and technique adherence.

Findings: The technology was validated by showing that the doses taken matched the number of audio recordings (r2 = 0.94, p<0.01). To demonstrate that audio analysis of inhaler use gives objective information, in vitro studies were performed. These showed that acoustic profiles of inhalations correlated with the peak inspiratory flow rate (r2 = 0.97, p<0.01), and that the acoustic energy of exhalations into the inhaler was related to the amount of drug removed. Despite training, 16% of participants exhaled into the mouthpiece after priming, in >20% of their inhaler events. Repeated training reduced this to 7% of participants (p = 0.03). When time of use was considered, there was no evidence of a relationship between adherence and changes in AQLQ (r2 = 0.2) or PEFR (r2 = 0.2). Combining time and technique the rate of adherence was related to changes in AQLQ (r2 = 0.53, p = 0.01) and PEFR (r2 = 0.29, p = 0.01).

Conclusions: This study presents a novel method to objectively assess how errors in both time and technique of inhaler use impact on clinical outcomes.

Trial registration: EudraCT 2011-004149-42.

Show MeSH