10.5061/DRYAD.GF1VHHMKM
Dickinson, John
0000-0002-1824-7402
University of Kent
Jackson, Anna
English Institute of Sport
Hull, James
Royal Brompton Hospital
Hopker, James
University of Kent
Fletcher, Hannah
King's College Hospital NHS Foundation Trust
Gowers, William
University of Kent
Molphy, John
0000-0003-0803-2907
Liverpool John Moores University
The impact of a heat and moisture exchange mask on respiratory symptoms
and airway response to exercise in asthma
Dryad
dataset
2020
Respiratory symptoms
Asthma
heat and moisture exchanger (HME) face mask
Asthma UK
https://ror.org/03z7xev21
AUK-IG-2016-332
2021-04-16T00:00:00Z
2021-04-16T00:00:00Z
en
137448 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Respiratory symptoms, including cough are prevalent in asthmatic
individuals when exercising. This study investigates whether a heat and
moisture exchanger (HME) face mask is effective in modulating exercise
induced bronchoconstriction (EIB) and post exercise cough in a cold, dry
environment in asthmatic individuals. Twenty-six participants diagnosed
with asthma (20 males, 6 females) completed three cycling exercise
challenges (EX) at 8 oC and 24% relative humidity (RH) in a randomised
order. Participants wore either an HME mask (MASK), sham mask (SHAM), or
no mask (CON). Following a 3-min warm-up participants completed 6-min
cycling at 80% peak power output. Before and after EX, maximal flow volume
loops were recorded. Post EX cough was monitored with a Leicester Cough
Monitor (LCM) for 24-hours. Results were analysed using repeated measures
ANOVA and Friedman’s tests and data presented as the mean ± SD or median
(IQR). Eleven participants failed to demonstrate EIB (i.e.>10% fall
in FEV1 post EX) and were removed from analysis. The % fall in FEV1
following EX in CON was greater than MASK (MASK: -6.0 (7.0), SHAM: -11.0
(11.0), CON: -13.0 (9.0) %; p <0.01). No difference was found
between EX in cough count per hour over the 24-hour monitoring period or
the number of coughs in the first hour post EX. HME masks can attenuate
EIB when exercising in cold, dry environments. The SHAM mask may not have
been entirely inert demonstrating the challenges of running randomised
control trials utilising control and SHAM conditions.
This study is registered on ClinicalTrials.gov (Identifier: NCT04302610).
Following approval from the Faculty of Sciences Research Ethics Advisory
Group for Human Participants, University of Kent (0881516) thirty-four
recreationally active participants exercising > twice per week (6 ±
2 hours) provided written informed consent to participate. All
participants had a clinician-based diagnosis of asthma however
participants who didn’t have a fall in FEV1 of ≥10% at two consecutive
time points following at least one of the exercise challenges (see below)
were not included in subsequent analysis. i.e. no evidence of
exercise-induced bronchoconstriction. Participants were excluded if they
used of oral corticosteroid daily, were hospitalised due to asthma in the
six months prior to study commencement and/or resting FEV1 <80% of
predicted value (Quanjer et al., 1994). All participants were free from
illness in the two weeks prior to assessment. Participants were instructed
to maintain their usual diet for the duration of the study, to avoid
exercise and caffeine for 24 hrs and 4 hrs respectively before each visit
and arrive at the laboratory at least 2 hrs postprandial. Study design In
a randomised cross-over design participants attended the laboratory on
five occasions (figure 1): Visit 1: Peak oxygen uptake (V̇O2 peak) test on
a cycle ergometer. Visit 2): Familiarisation. Visits 3-5): Standardised
cycle exercise challenge (EX) in a cold, dry environment. During the EX,
participants wore either an HME mask (MASK) (ColdAvenger® expedition
balaclava, USA, www.coldavenger.com), a sham mask (SHAM) which was the
same HME mask with holes cut across the entire ventilator cup and the
ventilator removed (figure 2), or no mask (CONT) wearing only the
balaclava to which the mask is attached. The EXs were completed in a
randomised order but at the same time of day. The time between each visit
was dependant on the participant’s current medication; participants
previously prescribed inhaler medication for asthma / EIB withheld
medication prior to each assessment (inhaled corticosteroids (ICS): 72
hours; inhaled long-acting β2-agonists (LABA): 48 hrs; inhaled
short-acting β2-agonists (SABA): the day of the test (Anderson and
Kippelen, 2013). Following each trial, participants had the same amount of
time back on their medication before once again stopping treatment before
their next EX. Participants who were not taking any asthma medication, had
a minimum of 48 hrs between trials. Visit details Visit One
Cough-specific health status was assessed with the Leicester Cough
Questionnaire (LCQ), which is a self-administered 19-item tool (total
score range 3-21; higher scores indicating better health status; Birring
et al. 2003). Anthropometric measures were taken and performed a
standardised incremental ramp test to volitional exhaustion to establish
Peak Power on a cycle ergometer (Lode; Corival, Groningen, Netherlands)
with simultaneous gas analysis (Cortex Metalyser 3b, CORTEX Biophysik
GmbH, Germany). Heart rate was recorded throughout (Polar RS400; Polar
Electro Oy, Kempele, Finland) and Peak Power Output (PPO) was recorded.
Visit Two Participants remained on prescribed asthma therapy and completed
the EX protocol as detailed below in a normal lab environment without a
mask, as means of laboratory testing familiarisation. Visits Three to
Five Participants completed a cough 0-100mm visual analogue scale (VAS)
(Spinou and Birring 2014). Airway inflammation was then assessed prior to
each challenge by determining fraction of exhaled nitric oxide (FeNO)
(NIOX VERO, NIOX, Aerocrine, Sweden) (Dweik et al. 2011). Resting lung
function was then measured by maximal flow volume spirometry (Spiro-USB
and MicroLab, CareFusion, Germany) in accordance with international
standards (Miller et al., 2005). Maximal flow-volume loops were
subsequently measured in duplicate at 3, 5, 7, 10- and 15-mins post
challenge, with the highest value at each time point used for analysis. If
there was a ≥10% fall in FEV1 post challenge at two consecutive time
points, 400 µg inhaled salbutamol was self-administered by the participant
and maximal flow loops were repeated 15 minutes post administration to
ensure FEV1 had returned to within 10% of baseline. The EXs were conducted
in an environmental chamber (TIS Services, Hampshire, UK) (8.6 ± 0.9 °C,
24.2 ± 4.2% RH) on a cycle ergometer (Lode; Corival, Groningen,
Netherlands). The EX protocol required participants to complete 3-minutes
of incremental cycling at a work rate of 60, 75 and 90% of their final
target power for one minute at each power output. They then cycled for 6
minutes at 80% of their peak power (Crapo et al., 1999; Ansley et al.,
2010). Heart rate was recorded throughout. Immediately after EX, cough
frequency was assessed objectively over 24 hours with the validated
Leicester Cough Monitor (LCM; Birring et al. 2006; Birring et al. 2008).
The LCM is an ambulatory system, which comprises a MP3 recorder
(ICD-PX333, Sony Corporation, Tokyo, Japan), a lapel free-field microphone
(LFH9173, Philips, Amsterdam, Netherlands) and a semi-automated cough
detection software. Coughs were detected as single events whether they
occurred in isolation or in bouts (Birring et al. 2008). Cough data was
analysed via a cough detection software based on the Hidden Markov model
as described by (Birring et al. 2008). Participants completed an
additional VAS 24 hours following the EX. Statistical analysis Data are
presented as mean ± SD unless otherwise stated. Shapiro-Wilk tests were
used to test for normal distribution. Differences between the three EX
conditions were examined using repeated measures ANOVA. Where data was not
normally distributed, Friedman’s test was used with post hoc pairwise
comparisons where appropriate. Spearman's rank correlation
coefficient was used to investigate the relationship between VAS score and
cough per hour, % fall in FEV1 and coughs per hour after EX or LCQ score
and cough count. All analysis was conducted using SPSS software, V.23
(SPSS, IBM, Armonk, NY, USA) with significance accepted at P <0.05.
Spearman's rank correlation coefficient was used to investigate the
relationship between VAS score and cough per hour, % fall in FEV1 and
coughs per hour after EX or LCQ score and cough count. All analysis was
conducted using SPSS software, V.23 (SPSS, IBM, Armonk, NY, USA) with
significance accepted at P <0.05.