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Validation of morning dip of peak expiratory flow as an indicator of the severity of nocturnal asthma. V Bellia, A Visconti, G Insalaco, G Cuttitta, G Ferrara and G Bonsignore Chest 1988;94;108-110 DOI 10.1378/chest.94.1.108 The online version of this article, along with updated information and services can be found online on the World Wide Web at: http://chestjournal.chestpubs.org/content/94/1/108
Chest is the official journal of the American College of Chest Physicians. It has been published monthly since 1935. Copyright1988by the American College of Chest Physicians, 3300 Dundee Road, Northbrook, IL 60062. All rights reserved. No part of this article or PDF may be reproduced or distributed without the prior written permission of the copyright holder. (http://chestjournal.chestpubs.org/site/misc/reprints.xhtml) ISSN:0012-3692
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Validation
of Morning Dip of Peak Flow as an Indicator of the of Nocturnal Asthma*
Expiratory
Severity Vincenzo
Bellia,
M.D.;
Gluseppe
Insalaco,
Giuseppe
Ferrara,
Aifredo
M.D.;
Giuseppina
M.D.;
M.D.;
Visconti,
and
Cuttitta,
Giovanni
M.D.;
Bonsignore,
M.D.,
Overnight
falls in peak expiratory flow (PEF) (with the dip of the index) may be considered the hallmark of nocturnal asthma. To validate the morning dip a quantitative marker ofthe degree ofnocturnal bronchoconstriclion, the dip was measured in 11 subjects (six with a history
morning
consistent
with
asthma)
undergoing
all-night
of lower respiratory resistance by a doublemethod. In six subjects, marked and recurrent in resistance were recorded, along with morning
monitoring
catheter increases
N
nocturnal
exacerbations
octurnal
of asthma
are
very
com-
mon, occurring in the majority of asthmatic patients’ and resulting in the early morning dip in peak expiratory flow (PEF).2 Recognition and evalua-
of nocturnal
tion
unfavorable non,
prognostic in
both
implications
hospitalized
of the
with
relationship
attacks
and
between
the
the magnitude
severity
has of
of nocturnal
of morning
dips
has
been
reported. The present study is aimed at investigating whether the extent ofthe morning dip ofPEF may be a reliable
indicator
quantitative
of the
severity
asthma by evaluating the behavior submitted to all-night monitoring
of nocturnal
of PEF in subjects of lower airway
resistance. MATERIALS The
following
subjects
AND
METhODS for the study: (1) four healthy
volunteered
men aged 27 to 36 years (two smokers and two (2) seven asthmatic
Inpatients
aged
three women; two smokers and five
nonsmokers);
and
18 to 44 years (four men and nonsmokers).
Four had extrinsic
asthmawith sensitization toDerinatophagoidespteronyssimus; three had intrinsic asthma. All but one reported the frequent occurrence of nocturnal chest tightness and wheeze; one of them (case 1) had
the ISfitUtO di Pneumologla dell’Unlversit#{224}, Istituto di Flsiopatolngia Respiratoria del Consigilo Nazionale della Richerche, Palermo, Italy
*From
Manuscript
Reprint
received
requests:
cerche, Istituto 90146 Ihlermo, 108
September
Dr Bonaignore, di FISIOpatOIOgIa Italy
16; revIsion
Consiglio Respiratoria,
accepted
January
icant
breathlessness
for resistance,
5.
Nazionale delis RIVia Trabucco 180,
and
were
wheeze.
Peak
as the duration
as well
increased,
was
closely
correlated
and average values for which resistance with the magnitude
of morning dips. Therefore, unlike the subjective report, PEF may be considered a reliable quantitative indicator of nocturnal
bronchoconstriction.
had a ventilatory arrest, three weeks
before
of the
All ophylline
room,
currently
taldng
sympathomimetics
beclomethasone,
or and the-
four of the
of stemicla
12 hours
in the emergency
was treated
bronchodilators,
preparations;
episode
which
study. were
inhaled
oral administration recent
the
patients
antimuscarinic
cited
unstable
emphasized,5
dips higher than 20 percent; however, on the following morning, only two of them reported having suffered signif-
was withheld
of the phenome-
patients
ofincreased instability ofthe airways so far no objective evaluation
as indicators the
because
and in outpatients with stable asthma.4 the importance of the larger swings in PEF
asthma3 Whereas
been
is important
asthma
F.C.C.P
before
ofarrest,
patients were also submitted to In all subjects but one, all therapy the study; in case 1, because of the
treatment
was kept
unchanged.
the two weeks preceding the study all of subjects were instructed to record PEF hourly from getting up in the morning to the time of going to bed in the evening; the measurement was performed in the standing position in triplicate, and the highest value was recorded on a diary chart The morning dip of PEF was calculated as the percentage ratio of the early morning to the maximum daily value ofthe day of study. Each subject slept for two consecutive nights in the sleep laboratory, the first night being aimed at acclimatizing the subject; only data from the second night were analyzed. In order to monitor patency ofthe lower airways and to rule out the occurrence of sleep-related upper afrway occlusive events, we measured upper afrway resistance, as well as lower respiratory resistance, using a partially modified version of the technique proposed by Hudgel et al.’ The following measurements were recorded both on paper for immediate control and on magnetic tape for further processing: (1) electroencephalogram, electro-oculogram, and submental electromyogram by conventional techniques to perform sleep staging; (2) inspiratory and expiratory flows by a pneumotachygraph (Fleisch No. 2) attached to an airtight face mask; (3) volumes by electronic integration of flow signal; (4) esophageal pressure by a balloontipped catheter placed in the lower third of the esophagus and connected to one port of a difirential transducer (Sanborn); (5) supraglottic pressure (Psg) by a second balloon-tipped catheter introduced through the nares and placed at a 15- to 17-cm distance at the supraglottic level; the catheter was connected to a port of a second pressure transducer (Sanborn); and (6) mouth pressure (PM) by a catheter placed in the face mask and connected to the second port of both the previously cited transducers to obtain differential pressures. Total lung resistance (R,J was measured by the isovolume During
Indicator of Severity of Nocturnal Asthma
Downloaded from chestjournal.chestpubs.org by guest on July 10, 2011 © 1988 American College of Chest Physicians
(BalSa
etal)
method,7
equal elastic
referring
pressure
transpulmonary
volumes;
this method
to different
flows at
one to keep the component constant and to refr any pressure change to the flow-resistive properties. Gas inertial phenomena were considered as negligible at low respiratory frequencies. Supraglottic resistance (l) was calculated as the ratio, (Psc- PM)N. Lower airway resispulmonary
tance (R,.) was calculated as the
allows
difference,
R-
R.
RESULTS
was performed
Monitoring
time
351
of
average,
77
±
sleep
minutes
time
(150±63
all rapid-
with
stages
non-REM
being
represented. In
the
six
recorded
average
with
dramatic
asthma,
nocturnal
were
patients
recurrent
throughout
maximum
increase
to the baseline
value
a positive the
night, percent
of409
in the
recorded
history
lbr in R
increases reaching
an
respect
with
supine
position
the onset of sleep. By contrast, in the seventh patient and in the healthy subjects, the increase in R, although noticeable, was far less marked (on the average, 227 percent). In only fbur out of the six patients with marked nocturnal exacerbations did one beibre
or more which,
of these in turn,
episodes result was accompanied
of breathlessness
awareness
subjects. subjects
On
the
reported
following
dips
and
experiencing
In the six patients
in an awakening, by the subjective wheeze
morning,
nocturnal
who underwent
in only
two
these
two
only nocturnal
attacks,
of PEF
and, respectively, the fbllowing (Fig R attained in the night (r = 0.90; average
R
measured
throughout
magnitude
highest
1): (1) the
p
