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In luence o mou hwashes on ex ended exhaled
ni ic oxide (FENO) analysis
Paul Guen he Lassmann-Klee, Lau i Leh imäki, Tuula Lindholm, L. Pekka
Malmbe g, Anssi Raimo An e o So ijä i & Päi i Pii ilä
To ci e his a icle: Paul Guen he Lassmann-Klee, Lau i Leh imäki, Tuula Lindholm, L. Pekka
Malmbe g, Anssi Raimo An e o So ijä i & Päi i Pii ilä (2018) In luence o mou hwashes on
ex ended exhaled ni ic oxide (FENO) analysis, Scandina ian Jou nal o Clinical and Labo a o y
In es iga ion, 78:6, 450-455, DOI: 10.1080/00365513.2018.1497802
To link o his a icle: h ps://doi.o g/10.1080/00365513.2018.1497802
© 2018 Medisinsk Fysiologisk Fo enings
Fo lag (MFFF)
Published online: 22 Oc 2018.
Submi you a icle o his jou nal
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ORIGINAL ARTICLE
In luence o mou hwashes on ex ended exhaled ni ic oxide (F
ENO
) analysis
Paul Guen he Lassmann-Klee
a
, Lau i Leh im€
aki
b
, Tuula Lindholm
c
, L. Pekka Malmbe g
d
,
Anssi Raimo An e o So ij€
a i
a
and P€
ai i Pii il€
a
a
a
Uni o Clinical Physiology, Helsinki Uni e si y Cen al Hospi al and Uni e si y o Helsinki, Helsinki, Finland;
b
Alle gy Cen e, Tampe e
Uni e si y Hospi al and Facul y o Medicine and Li e Sciences, Uni e si y o Tampe e, Tampe e, Finland;
c
Labo a o y o Clinical Physiology,
Finnish Ins i u e o Occupa ional Heal h, Helsinki, Finland;
d
Labo a o y o Clinical Physiology, Skin and Alle gy Hospi al, Helsinki, Finland
ABSTRACT
F ac ional exhaled ni ic oxide (F
ENO
) is used o assess eosinophilic in lamma ion o he ai ways. F
ENO
alues
a e in luenced by he expi a o y low a e and o ally p oduced NO. We measu ed F
ENO
a ou di e en expi a-
o y low le els a e wo di e en mou hwashes: ap wa e and ca bona ed wa e . Fu he , we compa ed he
al eola NO concen a ion (C
ANO
), maximum ai way NO lux (J0
awNO
)andai wayNOdi usion(D
awNO
)a e
hese wo mou hwashes. F
ENO
was measu ed in 30 olun ee s (heal hy o as hma ic) wi h a chemilumines-
cence NO-analyse a low a es o 30, 50, 100 and 300 mL/s. A mou hwash was pe o med be o e he meas-
u emen a e e y low a e. The ca bona ed wa e mou hwash signi ican ly educed F
ENO
compa ed o he
ap wa e mou hwash a all expi a o y lows: 50 mL/s (p<.001), 30 mL/s (p=.001), 100 mL/s (p<.001) and
300 mL/s (p=.004). J0
awNO
was also signi ican ly educed (p=.017), howe e , he e we e no signi ican di e -
ences in C
ANO
and D
awNO
. In conclusion, a ca bona ed wa e mou hwash can signi ican ly educe o opha yn-
geal NO compa ed o a ap wa e mou hwash a expi a o y lows o 30–300 mL/s wi hou a ec ing he C
ANO
and D
awNO
. The e o e, mou hwashes need o be aken in o accoun when compa ing F
ENO
esul s.
ARTICLE HISTORY
Recei ed 9 Ma ch 2018
Re ised 12 June 2018
Accep ed 17 June 2018
KEYWORDS
Ni ic oxide (NO); al eola
NO concen a ion (C
ANO
);
as hma; ac ional exhaled
ni ic oxide (F
ENO
);
maximum ai way NO lux
(J0
awNO
); mou hwashes;
ca bona ed wa e ;
in lamma ion; espi a o y
sys em; exhala ion; ai way
obs uc ion; o opha ynx
In oduc ion
Eosinophilic in lamma ion o he b onchial epi helium is a
ch onic p ocess o en leading o b onchial hype eac i i y and
ai way obs uc ion. Du ing in lamma ion, ac ional exhaled
ni ic oxide (F
ENO
) is mainly p oduced in he ai way epi he-
lium, ca alysed by inducible NO syn hase (NOS2) [1]. In clin-
ical p ac ice, assessing F
ENO
acili a es as hma diagnosis [2].
F
ENO
is a combina ion o ni ic oxide (NO) o igina ing
in he lung pe iphe y, he b onchioli, he b onchi and he
cen al la ge ai ways, and F
ENO
depends highly on he
expi a o y low a es. NO dynamics in he lung pe iphe y
de e mine o a la ge ex en F
ENO
measu ed a highe low
a es, while mainly b onchial NO dynamics de e mine F
ENO
measu ed a slowe low a es [3,4]. F
ENO
measu emen has
been p e iously ecommended a he expi a o y low a e o
50 mL/s [5,6]. The e is e idence ha F
ENO
alues o e
50 ppb (>35 ppb in child en) measu ed a his low indica e
eosinophilic ai way in lamma ion and he cu -o can be
applied o de ec as hma in symp oma ic indi iduals [7,8].
F
ENO
measu emen a mul iple lows a e used o es ima e
he ana omical o igin o NO in exhaled ai [9–12]. A simple
wo compa men model o he ai ways has been adop ed
[6] o de ine he al eola NO concen a ion (C
ANO
), max-
imum ai way NO lux (J0
awNO
) and ai way NO di usion
(D
awNO
)[13]. These es ima es ha e p o ided ex ended in o -
ma ion in subjec s wi h as hma [12–15].
In heal hy subjec s, a ac ion o F
ENO
seems o o igina e
in he uppe ai ways and o opha ynx, pa ly due o bac e ial
p oduc ion o NO and die a y in ake o ni a e [16–21].
Rinsing he o al ca i y wi h ca bona ed wa e lowe s
F
ENO
le els signi ican ly in heal hy and as hma ic subjec s
[22,23]. Al hough he ATS/ERS guidelines sugges ha a
mou hwash be o e F
ENO
measu emen s may educe o al
F
ENO
, i is no pa o he s anda dized clinical p ocedu e
[5], bu only ecommended in physiological esea ch [6].
Howe e , insing o he mou h wi h ca bona ed wa e has
been ou inely adop ed in ou labo a o y a he Helsinki
Uni e si y Hospi al p io o F
ENO
measu emen s since 1995.
The aim o his s udy was o compa e he e ec s o a ca bo-
na ed wa e mou hwash and a ap wa e mou hwash on F
ENO
a
di e en low a es, as well o analyse he e ec s o he mou h-
washes on C
ANO
,J0
awNO
and D
awNO
.Fu he mo e,weaimed o
in es iga e he epea abili y o he F
ENO
measu emen s.
Me hods
We ec ui ed 30 olun ee s aged 16–68 yea s, ei he heal h-
ca e wo ke s (n¼21) o pa ien s (n¼9). The pa ien s
CONTACT Paul Guen he Lassmann-Klee [email p o ec ed] Uni o Clinical Physiology, Helsinki Uni e si y Cen al Hospi al, PO Box 340, 00029 HUS/
Helsinki, Finland
ß2018 The Au ho (s). Published by In o ma UK Limi ed, ading as Taylo & F ancis G oup
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SCANDINAVIAN JOURNAL OF CLINICAL AND LABORATORY INVESTIGATION
2018, VOL. 78, NO. 6, 450–455
h ps://doi.o g/10.1080/00365513.2018.1497802
en olled ha e had as hma ic symp oms and we e p e iously
e e ed o F
ENO
es ing, ei he o he Labo a o y o
Clinical Physiology a he Uni e si y Hospi al in Helsinki o
he Skin and Alle gy Hospi al in Helsinki. Heal hca e wo k-
e s who olun ee ed we e included wi hou u he selec ion.
None o he subjec s we e excluded. All pa icipan s we e
asked o ill a ques ionnai e including ques ions ega ding
smoking habi s, as hma, alle gic hini is and COPD.
Nine pa icipan s epo ed ha ing alle gic hini is, six
as hma and one COPD. Two pa icipan s smoked egula ly,
one less han i e ciga e es a day, he o he om 5 o 15 a
day. F om a ailable medical eco ds, we sea ched o
espi a o y o sys emic diseases ha could in luence F
ENO
alues, eason o e e al o F
ENO
es ing and cu en medi-
ca ion. Nine pa icipan s had a ch onic espi a o y disease
o espi a o y symp oms. Among hese we e ou pa ien s
wi h as hma, h ee wi h espi a o y symp oms due o build-
ing dampness bu low o nega i e b onchial hype eac i i y,
one wi h eosinophilic b onchi is and ano he wi h Sj€
og en’s
synd ome. The pa ien wi h Sj€
og en’s synd ome had no
in e s i ial lung disease, p e iously uled ou h ough a high
esolu ion compu ed omog aphy. Six pa icipan s had p e-
sc ip ions o sho ac ing be a
2
-agonis s, ou used inhaled
co icos e oids egula ly, wo used an ihis amines and one
used leuko iene ecep o an agonis s. Spi ome ic da a we e
a ailable in 25 subjec s. None o hese subjec s had cu en
b onchodila o e e sibili y (de ined as inc ease in FEV1 o
FVC o e 12% and 200 mL) [24]. Demog aphic, an h opo-
me ic and spi ome ic da a a e summa ised in Table 1.
The F
ENO
measu emen s we e made ei he a he Skin and
Alle gy Hospi al o a he Finnish Ins i u e o Occupa ional
Heal h, bo h in Helsinki. The NO analyse s used we e chemi-
luminescence CLD 88 sp and he de ices we e
EXHALIZER
V
R
’sDwi hSPIROWARE
V
R
so wa e om Eco
Medics AG (D€
u n en, Swi ze land) and calib a ed acco ding o
he manu ac u e ’s ins uc ions by using ce i ied span gas
(AGA Gas BV, Ams e dam, Ne he lands) and NO ee ai by
using a ze o-ai il e (DENOX 88 uni ). The inspi ed gas was
NO ee (<5 ppb, maximum eco ded ac ional inspi ed F
ino
was 3.1 ppb). Be o e he measu emen s, he ul asonic low
senso was calib a ed wi h a calib a ion sy inge (Hans
Rudolph Inc., Shawnee, KS). F
ENO
measu emen s o each sub-
jec we e pe o med du ing wo consecu i e days. The low-
cha in Figu e 1 isualizes he o de o he p ocedu es. The
measu emen s we e made a ou di e en expi a o y low
a es V0(30, 50, 100 and 300 mL/s). The sequence o he low
a es was kep he same, s a ing wi h a 50 mL/s low a e, ol-
lowed by 30, 100 and 300 mL/s. The mou hwash p ocedu e
was de ined as insing he o al ca i y o 30–60 seconds wi h
100 mL o ap wa e o ca bona ed wa e . On he i s day, he
subjec s pe o med a mou hwash wi h ap wa e be o e he
measu emen s a he i s low le el, and hen epea ed he
mou hwash wi h ap wa e be o e measu ing a e e y low
le el. A e eaching he highes low le el, i.e. 300 mL/s, he e
was a 15 min pause be o e s a ing a new a ay. A e his
ime in e al, all measu emen s we e epea ed, bu 100 mL o
ca bona ed wa e was used o pe o m he mou hwash.
Du ing he second consecu i e day, all es s we e epea ed in
he same ashion (i.e. wo mul iple- low measu emen s o
F
ENO
wi h di e en mou hwashes, o alling wo a ays o es -
ing on each day). The mou hwashes we e no andomized,
since he ca bona ed wa e mou hwash has a signi ican ly lon-
ge e ec on F
ENO
han he ap wa e mou hwash [22].
A minimum o wo measu emen s o F
ENO
a each low
we e pe o med o ob ain an accep able alue. The measu e-
men s a each s age we e accep ed i i s a ia ion was no
mo e han 2 ppb. I mo e han wo a emp s we e needed o
ge ing a alid measu emen , he o al insing was epea ed.
To u he analyse he da a, a mean alue was ob ained om
ou single de e mina ions ( wo ob ained each day) o e e y
subjec a each low and mou hwash se ing.
Table 1. Demog aphic, an h opome ic and spi ome ic da a o he s udy pa icipan s.
nMean (SD) Range Spi ome y nMean (SD) Range
Age (yea s) 30 43 (14) 16–68 FVC (l) 25 4.1 (1.1) 2.65–6.69
Heigh (cm) 30 171 (8) 157–186 FVC (%
a
) 25 93 (16) 50–120
Weigh (kg) 30 73 (15) 49–109 FEV1 (l) 25 3.3 (0.9) 2.06–5.36
Female/male 17/13 57%/43% FEV1 (%
a
) 25 93 (16) 50–117
As hma 6 21% FEV1/FVC a io 25 0.80 (0.1) 0.69–0.98
Alle gic hini is 9 31% FEV1/FVC (%
a
) 25 98 (7) 88–125
Smoking 2 7%
COPD 1 3%
Da a p esen ed as mean (SD) o pe cen age o o al case numbe .
a
Pe cen age o p edic ed alue (p edic ed acco ding o Viljanen e al. [25]).
Figu e 1. Flowcha illus a ing he p ocedu es, mou hwashes and epe i ions pe o med du ing one day. Tap: ap wa e mou hwash, ca bona ed: ca bona ed
wa e mou hwash.
SCANDINAVIAN JOURNAL OF CLINICAL AND LABORATORY INVESTIGATION 451
The bo led ca bona ed wa e used o he mou hwash
was comme cially a ailable (HARTWALL VICHY
ORIGINAL
V
R
, Oy Ha wall Ab, Helsinki, Finland) and had a
decla ed pH o 5.7–5.9; he ap wa e used had a pH o 8.3.
Mo e de ailed in o ma ion ega ding he solu ions can be
ound unde Lassmann-Klee e al. [22].
All ecommenda ions acco ding o ATS/ERS we e ol-
lowed, excep om he selec ion o a wide ange o expi a-
o y lows and using a mou hwash [5]. All subjec s e ained
om smoking ou hou s, om d inking co ee wo hou s
and om ea ing and d inking one hou be o e he s udy.
Also s enuous exe cising p io measu ing was discou aged.
E hical commi ee app o al was ecei ed (99/13/03/00/
15) and we ollowed he e hical p inciples s a ed in he
Decla a ion o Helsinki [26].
S a is ics
Analyses we e pe o med using IBM
V
R
SPSS
V
R
s a is ics so -
wa e e sion 22 (A monk, NY), RKWARD
V
R
e sion 0.6.5
on end and RSTUDIO
V
R
e sion 1.1.383 on end o he R
s a is ics language (THE R FOUNDATION
V
R
, Vienna,
Aus ia), and we pa ially used GRAPHPAD
V
R
PRISM
V
R
e -
sion 5.04 o ob ain he g aphs (La Jolla, CA). The compa i-
son o F
ENO
was made using a Wilcoxon es o pai ed
p obes. We accep ed a signi icance le el o a¼0.05 as sig-
ni ican . The mean (SD) was ob ained o each subjec om
ou F
ENO
measu emen s a e each mou hwash a lows 30,
50, 100 and 300 mL/s, espec i ely. The median and he
median absolu e de ia ion (MAD) was calcula ed oo [27].
To p o e he accu acy o he measu emen s, we used he
coe icien o a ia ion (c
), de ined as he quo ien o s and-
a d de ia ion (SD) and mean. We de ined a o al mean
alue o c
<10% as accep able. C
ANO
,J0
awNO
and D
awNO
we e calcula ed using a nonlinea loga i hmic ans o m-
a ion (we used s a ing es ima ed alues o he quad a ic T
ans o ma ion, a second o de app oxima ion) acco ding o
Eckel e al. [11] using ollowing equa ion:
log FENO ¼log J'awNO
DawNO
þCANOJ'awNO
DawNO

DawNO
_
V
!
þe(1)
C
ANO
,J0
awNO
o D
awNO
we e also calcula ed using he
H€
ogman and Me il€
ainen algo i hm (HMA), wi h mean F
ENO
and mean V0 alues o he low a es: 30 mL/s, 100 mL/s
and 300 mL/s [12]. Cases wi h nega i e alues o C
ANO
and
wi h ailu e o consis ency check we e no uled ou .
The compa ison o C
ANO
,J0
awNO
o D
awNO
be ween
mou hwashes was made using a Wilcoxon es o pai ed
p obes. All a ge a iables we e no no mally dis ibu ed
(Shapi o–Wilk’s es ). The di e ences be ween c
we e ana-
lysed wi h a Wilcoxon es when compa ing mou hwashes.
A compa ison o all calcula ed c
esul s was made wi h
F iedman’s wo-way ANOVA.
Resul s
The esul s o F
ENO
measu emen s a mul iple low le els
a e lis ed in Table 2 and isualised in Figu e 2. Indi idual
F
ENO
alues a e isualised in Figu e 3.F
ENO
anged be ween
4.4 and 221.6 ppb and he median was 14.94 (MAD: 6.76)
ppb a a low a e o 50 mL/s a e insing wi h ap wa e .
The mou hwash wi h ca bona ed wa e educed F
ENO
sig-
ni ican ly compa ed o he ap wa e mou hwash a e e y
low a e.
Table 2. Summa ized esul s o F
ENO
a e e y low a e and mou hwash ei he wi h ap wa e o ca bona ed wa e .
F
ENO
(ppb) Median MAD IQR p
a
Mean (SD) Di e ence
b
Mean c
c
Flow 30 mL/s, ap wa e 22.86 10.11 20.4 .001 39.21(57.04) –4.6% 8.6 (4.5)
Flow 30 mL/s, ca bona ed wa e 20.11 9.49 20.7 37.40(59.28) 7.3 (5.0)
Flow 50 mL/s, ap wa e 14.94 6.76 13.3 <.001 27.27(40.19) –6.4% 8.4 (6.2)
Flow 50 mL/s, ca bona ed wa e 14.91 7.24 14.4 25.51(38.01) 6.6 (3.9)
Flow 100 mL/s, ap wa e 9.03 3.91 8.8 <.001 15.41(21.58) –4.4% 7.0 (6.6)
Flow 100 mL/s, ca bona ed wa e 8.15 3.68 8.7 14.74(21.72) 6.1 (4.0)
Flow 300 mL/s, ap wa e 3.84 1.36 3.2 .004 6.03(7.29) –4.2% 6.9 (4.1)
Flow 300 mL/s, ca bona ed wa e 3.53 1.31 3.0 5.77(7.45) 8.0 (5.3)
Da a p esen ed as median, median absolu e de ia ion (MAD), in e quan ile ange (IQR), n¼30. Mean c
calcula ed om indi-
idual c
o F
ENO
(consis ing o a leas ou alid F
ENO
esul s o each low a e and mou hwash).
a
Wilcoxon’s signed anks es .
b
Rela i e dec ease o he mean.
c
P esen ed as mean (SD) in pe cen .
Figu e 2. F
ENO
measu ed a mul iple expi a o y low le els a e di e en
mou hwashes. Pai s compa ed wi h he Wilcoxon signed- ank es .
452 P. G. LASSMANN-KLEE ET AL.
The mean c
o F
ENO
s ayed unde 10% o all low le els.
Compa ing he c
be ween ap wa e insing and ca bona ed
wa e insing, no signi ican di e ence was ound a any
low le el (a 30 mL/s p=.094; a 50 mL/s p=.125; a
100 mL/s p=.245; a 300 mL/s p= .688). Analysing c
o all
low le els and mou hwashes esul ed in no di e -
ence (p= .202).
When compa ing J0
awNO
be ween mou hwashes, he
median J0
awNO
o ca bona ed wa e was signi ican ly lowe
using bo h models. C
ANO
and D
awNO
did no di e signi i-
can ly be ween bo h mou hwashes. These esul s a e sum-
ma ized in Table 3.
The NO ac ion o inspi ed gas was a all imes below
20 ppb as ecommended, ha ing a mean alue o 0.35 ppb
(SD 0.34) [5].
Discussion
Mou hwashes
We ound a s a is ically signi ican di e ence in F
ENO
be ween mou hwashes a all expi a o y low le els. F
ENO
was
s a is ically signi ican ly lowe a e insing wi h ca bona ed
wa e compa ed o ap wa e a all expi a o y low le els.
This con i ms p e ious s udies in which ca bona ed wa e
was used o pe o m a mou hwash [22,23], and sugges s
endo semen o a ca bona ed wa e mou hwash p io mul-
iple- low es ing.
In he p esen s udy, he di e ence be ween mou h-
washes was ca. –5% a all low le els. This dec ease o
F
ENO
be ween mou hwashes equals ou p e iously
obse ed educ ion. We demons a ed ecen ly ha bo h
ca bona ed wa e and ap wa e mou hwashes lowe F
ENO
signi ican ly compa ed wi h he baseline and obse ed an
immedia e dec ease o F
ENO
a e a ca bona ed wa e
mou hwash o –18% and o –13% a e a ap wa e
mou hwash [22]. Addi ionally, Pii il€
a e al. [23] ound a
50 mL/s a dec ease om baseline (wi hou mou hwash) o
ca. –10% a e a ca bona ed wa e mou hwash in a heal hy
popula ion. In compa ison, p e ious mul iple low s udies
ha e ound a ela i e dec ease in F
ENO
o ca. –10% a e a
chlo hexidine mou hwash in child en and adolescen (bo h
as hma ic and heal hy) [28] and o ca. –15% in heal hy
adul s [29].
Fu he mo e, he ap wa e mou hwash’s e ec is sho -
las ing, only wo minu es. On he o he hand, he ca bo-
na ed wa e mou hwash’s e ec is longe , las ing 12 minu es,
and mo e e ec i e i compa ed wi h ap wa e [22]. Fo his
0
0204060
10
20
30
FENO (ppb)
Subjec s
Mou hwash
Ca bona ed
Tap
Figu e 3. Indi idual F
ENO
alues measu ed a mul iple expi a o y low le els a e di e en mou hwashes. O dina e ep esen s he indi iduals (n¼30), abscissa ep-
esen s F
ENO
(ppb) a mul iple expi a o y low le els a e : ca bona ed wa e mou hwash (black do s), and ap wa e mou hwash (g ey hombi). Abscissa unca ed
a 75 ppb. Subjec s 1 and 2 had highe F
ENO
(ppb) alues (no shown). The missing highe alues ( ap wa e /ca bona ed) o subjec 1 a e: 128/128, 85/79; and o
subjec 2 a e: 311/322, 222/208, 117/117.
Table 3. Resul s o J0
awNO
,C
ANO
and D
awNO
, a e ca bona ed wa e o ap wa e mou hwash.
J0
awNO
(pL/s) p
a
C
ANO
(ppb) p
a
D
awNO
(pLs
–1
ppb
–1
)p
a
Tap wa e 836.36 (457.58) .015 0.88 (0.48) .715 14.19 (7.52) .299
Ca bona ed wa e 829.97 (443.12) 0.92 (0.33) 18.60 (3.87)
Tap wa e
b
796.88 (449.86) <.001 1.00 (0.39) .598 15.63 (6.95) .871
Ca bona ed wa e
b
724.96 (392.60) 1.04 (0.30) 15.28 (3.67)
Da a p esen ed as median (median absolu e de ia ion), n¼30.
a
Wilcoxon’s signed anks es .
b
Calcula ed wi h H€
ogman and Me il€
ainen algo i hm.
SCANDINAVIAN JOURNAL OF CLINICAL AND LABORATORY INVESTIGATION 453

eason, we did no andomize he subjec s in he p esen
s udy and pe o med he measu emen s wi h ap wa e i s .
Ou da a we e accu a ely collec ed, since he in a-indi-
idual c
o F
ENO
s ayed low and he mean c
below 10%.
We did no ind a di e ence in c
be ween mou hwashes.
The c
a 100 mL/s is simila o p e iously epo ed by
Ek oos e al. [30] o a heal hy male popula ion aking in o
accoun a ime pe iod o maximal 24 hou s.
Mul iple low F
ENO
and mou hwashes
As we expec ed, J0
awNO
was signi ican ly lowe a e he ca -
bona ed wa e mou hwash compa ed o he ap wa e
mou hwash. The e was no s a is ically signi ican di e ence
be ween mou hwashes when analysing C
ANO
and D
awNO
.
We e i ied his esul s wi h es ima ed alues o J0
awNO
,
C
ANO
and D
awNO
and wo di e en models. This u he
s eng hens ou esul , ha he ca bona ed wa e mou h-
wash a ec s he ai way ac ion (due o o al NO educ ion)
and no he pe iphe al al eola NO, nei he he NO di u-
sion. We could s a e he hypo hesis ha he ca bona ed
wa e insing p o ides mo e exac alues (wi hou o al con-
amina ion) in gene al. Heijkenskj€
old-Ren zhog e al. pub-
lished simila indings when analysing J0
awNO
and C
ANO
a e a chlo hexidine mou hwash [28]. This is in con as o
esul s by Malino schi e al. [29] who ound also a dec ease
in C
ANO
a e a chlo hexidine mou hwash. Bo h used a
umpe -shaped model wi h co ec ions o axial di usion
(TMAD). Ke ckx e al. [31] demons a ed ha , when using
a model co ec ing o axial di usion o es ima e C
ANO
in
as hma ic pa ien s (unobs uc ed and well-managed), C
ANO
is no mal, e en when J0
awNO
is ele a ed. This has been con-
i med also o pa ien s wi h se e e as hma and du ing
exace ba ion [32].
Fo ou pu poses, we employed a wo compa men
model o he lung [4], wi hou conside ing axial di usion
[9], and applied a obus ma hema ical model [11]. This
model was es ed p e iously exac ly a he same low le els
by Eckel e al. and did no impose low limi a ions unlike
o he models [11]. We ob ained also alues using he HMA
(wi hou axial di usion) and he esul s be ween mou h-
washes we e simila . Al hough esul s om models wi h and
wi hou axial di usion a e no di ec ly equi alen , an ana-
logy can be made be ween he main indings o di e -
en s udies.
The s eng h o ou s udy was using di e en pa ame e s
o examine he e ec o he ca bona ed wa e mou hwash
and o ha using wo di e en ma hema ical models. Ou
calcula ions wi h Equa ion (1) p o ided nega i e alues o
C
ANO
in i e cases o ap wa e mou hwash and ou cases
o ca bona ed wa e mou hwash, which we e no excluded.
A simila amoun o nega i e alues we e ob ained wi h he
HMA. This has been a egula p oblem wi h o he models
p o iding a g ea e p opo ion o nega i e concen a ion
alues. We dis ega ded he impo ance o hese da a, since
he compa ison o C
ANO
be ween mou hwashes showed no
di e ence (e en when eplacing hese alues o ze o). Ou
ex ended analysis o J0
awNO
,C
ANO
and D
awNO
ound hese
alues compa able o p e ious esul s in a heal hy popula-
ion [33]. All esul s o C
ANO
we e unde 2.3 ppb and none
o he subjec s had a medical condi ion associa ed wi h
in e s i ial lung disease, he e o e we assume ha he sub-
jec s wi h measu ed F
ENO
o e 25 ppb (n¼7) had an ele-
a ed ai way p oduc ion o NO.
Limi a ions and implica ions
We acknowledge he limi a ion o no andomizing he
o de o he expi a o y lows le els. Howe e , he limi a ion
was imposed by he na u e o he low le els used, i.e. he
high low ep esen ing an expi a o y bu den o he pa ici-
pan s. P e ious s udies epo ed a dec ease in F
ENO
a e
o ced expi a ions [34–36]. We selec ed on pu pose an
inc emen al low o de o a oid he high low expi a ion
in luencing he slowe expi a ion manoeu es.
The ap wa e used o compa e he e ec o ca bona ed
wa e had a pH alue o e 8. The ap wa e in Eu opean
coun ies has a pH o 6.5–9.5 uni s (Council Di ec i e 98/
83/EC o 3 No embe 1998 on he quali y o wa e in ended
o human consump ion) and his ange also complies wi h
WHO guidelines. Many coun ies may ha e lowe ap
wa e ’s pH alues han 8. This may enhance he ap wa e ’s
e ec on o al F
ENO
and lowe he di e ences be ween ap
wa e and ca bona ed wa e . Ne e heless, u he s udies
a e needed o elucida e i he pH is he c ucial ac o o he
mou hwash solu ions.
Ca bona ed wa e poses an ideal candida e o pe o m-
ing a mou hwash be o e mul iple low measu ing. I elimi-
na es o al NO in e e ence mo e e ec i ely han ap wa e
and o a p olonged pe iod o ime. Ou ecen publica ion
[22] a gues o he clinical applica ion o a mou hwash
be o e F
ENO
measu emen . He e, we demons a e i in luen-
ces only he ai way ac ion o F
ENO
, and using ca bona ed
wa e as a mou hwash, in a mo e p onounced way.
P obably one mou hwash p ocedu e wi h ca bona ed wa e
may su ice when pe o ming a ou ine mul iple- low in es-
iga ion, bu epe i ions migh be use ul i exac alues a e
needed, e.g. in physiological esea ch.
Conclusions
We conclude ha a ca bona ed wa e mou hwash can sig-
ni ican ly educe o opha yngeal NO compa ed o a ap
wa e mou hwash a expi a o y lows o 30–300 mL/s wi h-
ou a ec ing he C
ANO
no he D
awNO
. We imply ha a ca -
bona ed wa e mou hwash is sui able o ou ine mul iple-
low F
ENO
-analysis and e iden ly use ul in clinical esea ch.
This s udy s eng hens he iew ha mou hwash p ocedu es
shall be aken in o accoun when compa ing F
ENO
alues.
Acknowledgemen s
We hank he s a membe s: Sa i Fische , Helena Punka i and Elina
Vou ilainen o pe o ming he F
ENO
measu ing and also Tommi
Pallasaho o da a collec ion.
454 P. G. LASSMANN-KLEE ET AL.
Disclosu e s a emen
No con lic s o in e es a e decla ed by he au ho (s).
P€
ai i Pii il€
a h ps://o cid.o g/0000-0002-2535-4409
Funding
This wo k was suppo ed by he Nummela Sana o ium Founda ion
(PP 2015, 2017) (AS 2016), Finnish S a e Funding o Uni e si y-Le el
Heal h Resea ch (TYH: 2013354), The Resea ch Founda ion o he
Pulmona y Diseases (PLK 2017, 2018), Tampe e Tube culosis
Founda ion: Ee o H€
am€
al€
ainen (PLK 2017, 2018), Ida Mon in
Founda ion (PLK 2017), V€
ain€
o and Laina Ki i Founda ion (PLK 2017,
2018) and he No dic Council o Minis e s: No dFo sk.
ORCID
Paul Guen he Lassmann-Klee h p://o cid.o g/0000-0002-
5592-4994
P€
ai i Pii il€
ah p://o cid.o g/0000-0002-2535-4409
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