RESPIRATORY
RATE,
TIDAL
VOLUME
AND
VENTILATION
OF
NEWBORN
INFANTS
IN THE
PRONE
AND
SUPINE
POSITIONS
W. T. Bruns, M.D., K. 0. Loken, B.A., and A A. Siebens, M.D.
Department of Pediatrics and the Respiratory and Rehabilitation Center, University of Wisconsin School of Medicine
Supported by a grant from the Wisconsin Alumni Research Foundation.
ADDRESS: (A.A.S.) Rehabilitation Center, University Hospitals, 1300 University Avenue, Madison 6,
Wisconsin. (W.T.B.) 8430 W. Capitol Drive, Milwaukee 22, Wisconsin.
PEDIATRICS, September 1961
388
T
HE POSITIONING of newborn infants iscommonly determined by the desire to
prevent aspiration of gastric contents and to facilitate bronchial drainage. The effect of body position on breathing in newborn
infants is unknown except for observations on respiratory rate.’ Studies in adults,
how-ever, have demonstrated a number of
changes in pulmonary function with
alter-ation of body position.2 The present
inves-tigation was undertaken to measure the
ef-fects of prone versus supine positions on
the respiratory rate, tidal volume and res-piratory pattern in infants.
METHODS AND SUBJECTS
The body plethysmograph used for the study differed only in minor modifications
from the one described by Cross.3 The in-fant’s body was enclosed in a fully trans-parent lucite chamber (volume, 27 lit)
through the lid of which the infant’s face protruded. A rubber gasket permitted air-tight closure of the lid; an oval pneumatic
cuff* placed in the lid opening provided an
airtight seal around the infant’s head by
encirculating the face from the mandibular
area to the crown.
Changes in intra-thoracic air volume dur-ing breathing produced fluctuations in in-tra-plethysmographic air pressure. Pressure was converted to volume after the
plethys-mograph had been calibrated by introduc-ing and withdrawing known volumes of air at a frequency comparable to the infant’s
respiratory rate. Pressure was recorded with a Statham Transducer (PM97TC) and
o j j Monaghan and Company, Denver, Colo-rado.
a multi-channel recorder (Gilson
minipoly-graph).
The study room was air conditioned; the temperature inside the plethysmograph varied from 25 to 29#{176}Cbut was kept con-stant during an experiment. The infants
breathed room air.
The following criteria were used in de-termining whether a study was to be in-eluded in this report.
1. The infant was asleep in the plethys-mograph for 10 minutes prior to recording and slept while the record was obtained. When single muscular twitchings occurred, the records were accepted as long as there
had been no change in the pattern of
respi-ration. Records were discontinued when-ever the infant cried, fussed or gasped.
2. A recording of at least 30 minutes was
obtained. This was divided into three
parts: 10 minutes with the infant supine, 10 minutes with the infant prone and 10 mm-utes with the infant again supine. Longer records and a different sequence of posi-tional changes were used in some infants.
The plethysmograph was not opened
dur-ing these sequences.
3. The plethysmograph remained
air-tight in each new position.
4. The infant’s upper air passage
re-mained unobstructed throughout the study
as recognized from a 20-second high speed recording at the end of each 10-minute
pe-riod.
Most newborn infants tolerated the
ap-plication of the pneumatic cuff without
fussing; some infants, however, required
ARTICLES 389
* All infants delivered spontaneously or by outlet forceps from cephalic presentation. t Nine-minute recording.
prone to supine or vice versa was achieved
by picking up the foot end of the plethys-mograph and moving it through an arc of 180 degrees. Supportive devices inside the
transparent chamber prevented major
po-sitional changes of the infant while it was turned. Impediments to motion of chest and abdomen in either supine or prone positions were no greater than those in a
crib.
No attempt was made to change the
rou-tine feeding schedule of the nursery to fa-cilitate these studies or to study the influ-ence of feeding upon respiration.
Experi-ments took place at varying times after reg-ular breast or bottle feeding.
The calculation of data was taken from the last 5 minutes of every 10-minute
re-cording. Ventilation was calculated by add-ing the tidal volume of each breath during
the 5-minute interval. All volumes recorded were converted to body temperature, am-bient pressure saturated (BTPS).
Sixty-one normal newborn infants deliv-ered at the University Hospitals, Madison, Wisconsin, were selected at random for
study. An additional 11 infants admitted to
the infant ward of the Children’s Hospital, University Hospitals, were included with the following findings: cleft palate in 3;
congenital heart disease in 2; erythroblas-tosis in 1; prematurity in 5. The age ranged
TABLE I
DATA ON RESPIRATORY RATE, TIDAL \OLUME AND VENTILATION IN NEWBORN INFANTS
/flf(Iflj* Sex Race
Age ( aya) -Weight (gm) Time Fed &f Study (hr) Position Respirations per %finute Tidal Volume (ml) Ventila-lion (mI/mm)
A M IV 10 (hr) ,98O Not fed prone
supine prone 5 3 6 17.7 18.1 17.1 44 -115 445
B F Sp ATIl 14 (hr) 3,405 Not fed supine
prone supine prone 8 6 30 30 .O O .7
17.9 18.l 615 538 530 543
C :I \V 1 ,l55 f supine
prone supinet 47 48 48 11.4 11.6 10.9 543 554 54
I) M N ,Sl() supine
prone supine 37 48 37 14.1 11 . 13.7 5l6 536 503
E M W 3 3,490 f supine
prone supine 74 55 69 F1.0 13.3 1Q8 886 733 846
F F W 4 2,75() I prone
supine prone supine 38 39 3 37 15.5 15.1 17.1 16.2 590 588 564 599
G F W 14 ,835 prone
IrantD
tOsec.
‘In1nt
G
L
lOsec
Inlant
E
[ lOec.
390 RESPIRATION IN NEWBORN
0
i
ol
CII
E
0Fic. 1. Representative records of infants’ breathing, showing regular breathing
ARTICLES
FIG. 2. Record of periolic- breathing of Infant R in supine position.
from 2 hours to 6 weeks.
Resistance of the infants to change of
I)osition was the greatest single difficulty
encountered. This response of the infants
was assumed to be a normal reaction to
be-ing turned heels over head, a procedure
performed twice during each experiment.
Because the infants commonly did not
re-main sound asleep, it was necessary to
re-Peat these studies two to seven times in
each instance.
RESULTS
Only 7 of 181 exl)eriments were attended
by
circumstances that coniplied with the requirements stated above. The sevenin-fants (Table I) were normal mature
iww-borns with the exception of one twin
pre-mature infant who was born after :37 \Veeks
gestation and weighed 2,155 gui.
The results obtained for the SuI)ilie
poSi-tion compare with those reported
by
oth-ers.3’
Mean values and extremes for respira-tory rate were 42.6 (23 to 74) breaths per
minute in the supine position as compared
to 37.3 (25 to 55) breaths per minute in the
prone position. Corresponding figures for
tidal roltime were 15.2 (10.9 to 22) ml in the supine position, as compared to 16.3
(11.2 to 20.7) ml in the prone position. For
ventilation the values were 611 (415 to 768)
ml per minute in the supine position and
585 (442 to 780) ml per minute in the prone
position. The small differences between
means were of the same order of
magni-tilde as differences between duplicate
measurements in the same position. The’ were, therefore, ascribed to variability of the measurement rather than to the effect
of position.
Two infants slio-ed greater changes. In
Infant D, the respiratory rate increased
from 37 p#{128}minute in the supine to 48 per
minute in the irie 1)OSitiofl l)ut the
yen-tilation reniained unchanged. Infant E
demonstrated a decrease in both rate and
ventilation when placed in the prone
posi-hon. Breathing in this infant was periodic
and irregular, however, in contrast to the
i-egular rhythm of the other infants (Fig. 1).
Two infants with marked periodic
breathing (Fig. 2) had bouts of apnea and
cyanosis when they were placed in the
FIG. -3. Record of breathing of Infant R in P#{176}#{176}’and supine 1)OSitiOfl. This is one of four similar tracings obtained on different days. Five bouts of apnea and cyanosis (A) occurred, each lasting longer than 30 seconds. The return to supine position is followed by periodic breathing (rig/it s-ide of record). At arrow,
392 RESPIRATION IN NEWBORN
prone position. In one of these this effect was demonstrated in each of four studies
performed on different days. The apnea
lasted from 8 to 63 seconds (Fig. 3). This patient had pulmonic stenosis without signs of cardiac insufficiency. Simultaneous
elec-trocardiograms showed no gross changes prior to or during the apnea. Neither
re-breathing nor breathing ovygen produced apnea when this patient lay in the supine position. The other infant with periodic
breathing and bouts of apnea when prone was normal. Satisfactory records were not obtained; periods of apnea were clearly seen at the crib side, however, when the infant was placed in the prone position.
COMMENT
Kravitz et a!.’ reported that, by visual counting, no significant difference in respi-ratory rate was seen when mature newborn
infants were changed from the supine to the prone position. Our results obtained with the plethysmographic method confirm
these observations. We found, in addition, that the ventilation is not influenced by this change in position. Although the rigid criteria adopted for study (Table I) ex-eluded the majority of observations, data from infants with imperfect records con-firmed those tabulated.
Geubelle4 has shown that the respiratory
performance of infants is influenced by food intake. The effect of this as well as other variables was controlled in our study
by recording respirations continuously and by placing the infant in the original posi-tion at the end of the test period.
\Ve succeeded in obtaining acceptable
records in only one of the two infants who had shown periodic breathing. This infant with congenital heart disease consistently showed intervals of apnea when prone. It could not be ascertained whether this breathing pattern was related to the car-diac disease; this association has been
re-ported, however, in adults with chronic cardiac decompensation in the recumbent position.5
The supine position was preferable to
the prone position in these two infants.
Whether this is generally true of mature in-fants with periodic breathing is conjectural. Position is known to affect the breathing
of premature infants exhibiting periodic
breathing. In these, however, periodicity
is reduced rather than increased by the prone position;1 the advantages of being supine are correspondingly less obvious. Indeed, because respiratory rate is
com-monly increased, it has been suggested that
ventilation is also increased when these
in-fants are prone.6
Periodic breathing has been attributed
to depression or immaturity of the
respira-tory
center,
to
slowed cerebral blood flow and possibly to changes in pulmonary com-pliance.7 Although some of these factors have also been alleged to cause apnea, thepathogenesis of this state has not been firmly established by several studies on this
subject in newborn and premature
in-SUMMARY
The respiratory rate, tidal volume and
ventilation were measured in newborn
in-fants with a body plethysmograph. A
con-tinuous recording revealed that, with one exception, no significant change occurred
in
these parameters when seven mature in-fants were turned from supine to prone position or vice versa. Two mature in-fants with periodic breathing, one of whom had congenital heart disease, exhibited pe-nods of apnea when placed from the Sn-pine into the prone position.REFERENCES
1. Kravitz, H., et al.: The effect of position on the respiratory rate of premature and
ma-ture newborn infants. PEDIATRICS, 22:432,
1958.
2. Attinger, E. A., Monroe, R. C., and Segal,
M. S.: The mechanics of breathing in
different body positions. J. Clin. Invest.,
35:904, 1956.
3. Cross, K. \V.: The respiratory rate and ventila-tion in the newborn baby. J. Physiol.,
109:459, 1949.
ARTICLES 393
oxymetriques chez le nourrisson: II. Influence dIe 1’ ingestion du repas liquide. Acta
Paediat., 47:6, 1958.
5. Altschule, M. D., and Iglauer, A.: The effect
of position on periodic breathing in chronic cardiac deconipensation. New EngI. J. Med.,
259:1064, 1958.
6. Cross, K. XV.: quoted l)y Silverman, in Year-book of Pediatrics, Chicago, Yr. Bk. Pub., 1959-60, p. 11.
7. Lyons, H. A., Burno, F., and Stone, R. W.: Pulmonary compliance in patients with pe-riodic breathing. Circulation, 17:1056, 1958.
8. Blystad, W.: Blood gas determinations on
premature infants: III. Investigation of
pre-mature infants with recurrent attacks of apnea. Acta Paediat., 45:211, 1956.
9. Illingworth, R. S.: Cyanotic attacks in
new-born infants. Arch. Dis. Child., 32:328, 1957.
10. Miller, H. C., Behrle, F. C., and SmuIl, N. W.:
Severe apnea and irregular respiratory rhythms among premature infants.
PEDI-ATRICS, 23:676, 1959.
11. Cook, C. D., et al: Studies of respiratory
physiology in the newborn infant: I. Ob-servations on normal premature and
full-term infants. J. Clin. Invest. 34:975, 1955.
THE ELECTROENCEPHALOGRAM OF THE
NORMAL CHILD, Alberto Fois, M.D.
(Translated and edited by Niels L. Low, M.D., F.A.A.P.). Springfield, Illinois,
Thomas, 1961, 124 pp., $6.75.
The following is the Preface to this book by Dr. Frederic A. Gibbs, who is well qualified to appraise it:
“The Italian edition of
L’Elettroencefalo-gramma del Bambino Normale was so lucid,
well illustrated and useful that it demanded an
English translation. Dr. Fois, in collaboration
with Dr. Niels L. Low, has produced an
Eng-lish edition which improves on the original.
“Verbal description cannot convey the mass of detail that is needed for the diagnosis and precise interpretation of electroencephalograms.
The written word can only underline certain
aspects of the electroencephalogram and
in-dicate its meaning. Accurate reading of such
tracings requires experience with actual
ex-amples; this book helps to provide such
ex-perience.
“The reduction of electroencephalograms to
two-thirds their original size, which is used
for the illustrations in the present volume, does not result in a loss of significant detail. The
eye and brain are astonishingly competent at ‘enlarging’ these productions so that they
correspond in scale to unreduced recordings.
Full scale reproduction, of course, has
ad-vantages but compactness also has advantages.
Decreased cost and convenience of reference
are strongly in favor of miniaturization. In this
book a large series of tracings and many im-portant facts have been compressed as far as
visibility and readability would allow; it is
little because it contains no fat.
“Emphasis on the electroencephalograms of infants is advantageous. They differ from those of children and adults and they consti-tute a special problem; although electroen-cephalograms of adults and school children are abundant, teaching material on infants’ electroencephalograms is scarce. This book performs an important service; it organizes
and systematically presents examples of the characteristic electroencephalographic patterns encountered in infants, and it will add to general understanding and practical com-petence.”
