An apparatus for resuscitation of newborn infants

AN

APPARATUS

FOR

RESUSCITATION INFANTS

OF NEWBORN

LEONARD H. BISKIND, M.D., AND EDUARD EICHNER, CLEVELAND, OHIO (Prom the Departments

of Obst&%cs

and Gynecology,

A

Mount

M.D.

S%nai Hospital)

UTHORITIESs 2 are now agreed that the treatment of asphyxia neonatorum should consist of proper posture, body warmth, removal of any substance obstructing the upper respiratory passages,and finally the administration of 100 per cent oxygen by a simple, effective and comparatively foolproof mechanism. Posture and warmth can be managed so readily in all hospital dclivery rooms that nothing additional need be added in that regard. Aspiration and resuscitation methods have been varied and manifold. It is not in the province of this paper to review these methods other than to say that with the replacement of manual methods by mechanical devises, simplification has been sought in order to obviate mechanical failure, and to improve efficiency. The one phase of the subject with which this paper deals is the presentation of a simple mechanical device for t,he purpose of administering 100 per cent oxygen to a newborn infant after first having thoroughly cleansed the air passages of obstructive material by means of an aspirator attached to the device. It is true that asphyxia neonatorum is best treated by preventing it’.” With prophylaxis in its present state, and with analgesia in widespread use, any consecutive series of births will indicate that approximately 15 per cent, of the newborn infants show some degree of asphyxia ranging from a mild pallor to cyanosis. The primary requisite of the ideal resuscitator is that it should be able to simulate natural respiration in volume and in rhythm. The flow should begin and end’gently as it does in normal breathing. The device should be adaptable for use on a human being of any age, size, or physical condition. It should be automatic and thus, once adjusted, not susceptible to the whims of the operator. The controls should be few, simple, and easily learned. The resuscitator should be safe, efficient and reliable and should be widely adaptable for use with any gas or gas mixture necessary for resuscitation. The authors were appointed a committee by the departments of obstetrics and gynecology at Mount Sinai Hospital in 1939 for the purpose of investigating and recommending a resuscitator for use in the delivery suite. Four resuscitators were investigated and subsequently obtained for trial use for from thirty to ninety days. The relative merits of these machines need not be discussed here. Our investigation, together with the unanimous opinion of the staff indicated that the Dann resuscitator was best fitted for our requirements. It is now close to two years during which time this resuscitator has been in constant use. In view of the fact that this machine has never heen described, it is being presented herewith and shown in Fig. 1. 147

148

.4MERICAK

JOURNAL

OF

OB+YlV:TRIC!S

.ZSD

(:I’SECOLOG\

Basirally, its main working part is a reciprocating, which slides gentl>- to and fro past openings through (or other gas) flows to and from the lnngs. This valve gas 1~10tol~OpCritlCcl 1)y thcl same sollI’(‘(’ of caomprcssctl yas

Fig.

tapered ~alvt: which oxygen is moved 1)~ it or gas mix1 nrc

1.

that flows to th e patient. The rate of puls@ion and the volume of each iration are controlled independently. The operator need not, be rap cone ierned aboi ut pressure--this adjusts itself automatically to the volu me of inflo NW,which is adjusted in each instance to the cap acity of

BISKIND

AND

EICHNER

:

APPARATUS

FOR

RESUSCITATION

149

the lungs. Exhalation is completely spontaneous ; the lungs empty themselves as they do in normal breathing, by the elasticity of the thoracic cage and of the lungs themselves. Oxygen is supplied to the resuscitator from a cylinder through a pressure reducing valve (A), set to the proper pressure at which the machine is designed to operate. A very small portion of the gas passes to the air motor (B). The rate control valve (C) controls the flow of this portion of the gas and thus increases or decreases the rhythm of the motor. By means of this valve, the rate is first adjusted to the needs of the patient (from 20 to 25 per minute for infants). Then applying the face mask (D) to the infant, the volume control valve (E) is slowly opened until proper chest expansion takes place. No further adjustment is necessary. This valve permits oxygen to flow from the pressurereducing device on the cylinder past a tapered reciprocating piston, through an expansion chamber to the patient. At the end of each inflow, the piston automatically cuts off the flow of oxygen and opens a port in the machine to the outside air which permits free exhalation, wit,hout suction of any kind. The piston then closes this port and gently opens another, through which oxygen again flows to the infant. The simple mechanism of this resuscitator has been so designed that even in newborn infants no delicate manometer has been found necessary to indicate the actual pressure of the oxygen mixture in the lungs. So long as the volume ,control valve is opened slowly and precisely to the point at which chest expansion occurs (a point easily observed), t,here is no danger of reaching excessive pressure in the lungs, even in The controls on the resuscitator permit the flow to premature infants. he adjusted exactly to the physiologic needs of the infant. Except for the indicators on the oxygen cylinder, gauges have purposely been omitted from this machine. Our experience with other resuscitators left us with the impression that such gauges provided a false sense of security-because the operator tends to watch the gauge or meter and not t,he infant. In addition, gauges and flow meters do not account for small leaks which may occur about the face mask. With this resuscitator, t,he operator gives undivided attention to the patient, adjusting the controls to the response of the subject. Some members of the staff felt that a manometer would be a helpful As a result, a sensitive water manometer addition to the resuscitator. (8’) was designed and attached to this machine. It indicates pressures up to 22 cm. of water (16 mm. of mercury) and does not permit the pressure to exceed this level. Through a small valve the manometer may be used or excluded as the operator desires. It is important to &member that it may be necessary for the initial pressure to exceed 22 cm. of water to inflate an atelectatic lung. Once the alveoli are opened insufflation of the same amount of air will usually give pressures belo; 15 cm. Attached to the resuscitator is a special aspirator (G). This also operates from the gas cylinder and provides rapid, rhythmic suction which may be varied by the operator from one to 160 cm. of water for preliminary removal of mucous or other material that may block the air passages and prevent ingress of the resuscitating gas. Together with a suitable collecting bottle, this aspirator is admirably adapted for use in the delivery room, in that it can be used as soon as the baby’s head is delivered. When so used, the entire resuscitator, which is mobile, is

150

AMERICAN

.JOURSAL

OF

OBSTETRICS

Ah-11

G1’ZXCOLOGY

moved alongside the mother. A sterile glass tube and rubber cat,hetcr is available for attachment to the aspirat.or tubing (FI) _ The obstetrician is t.hen handed the cathef cr already a.t.tached t.o the tubing by a nurse who, at the same time, sets the aspiralor in moi.ion. The obstetriciau then can a?spirat,e the nose, mouth, and pharynx heforc completing dclivery of the infant,. This aspirator has also been used successfully on several mothers, with the recovery of aspirated vomitus from the LI~IJC~I* respiratory tract,, and with the avoidance of severe complications. As will bc noted in lq’ig. 1, the rcsnscitator is al.lached to a mobile steel cart (I) which rolls noisrlessly. This cart holds a large oxygen cplinde~ and occupies a floor SJXKT of 20 lay 30 inchtw. lt has a. drawer sl>a<‘tf (J) for fact masks, intubator, and ot,hcar acccssoric~s (adult mask 1K ( 1. As previously mentioned, the increasing lose ot’ analgesia and anesthesia in parturicnt mothers has made f&al asphyxia a mow common occurrence. Various measures havcl 1~~1 em ~~lo,vcd to initiate respir;ltion in the newborn infant, hot,h mann;ll and mechanical, 11~1. nOIle havcl been so simple, rapid and effective as the gentlr pulsating flow of this A particular advantage of this r*(~spi~;~t:o~ is its aMit> resuscitator. to expend the atrlectatic Inn, - of thth rr~~h0r11 infant. Machines i 1t which the pressure only is eont,rollctl arty of’ten in~apal~lr to initial filling of t,he lungs bcca\lse this requires greats pressure (owing t,o the adhesion of’ the lmlg surfaces) t.han subsequent, inflations. In this resuscitator t.lre volume is adjusted to the needs of thtl infant ant1 this, once ;~tljustc~tl~ ran never exceed the capacity of the Illngs. At llir same lime the machine, when this is necessary, automatic+ally pc’rmits enol~gh prcssrlrt’ I I) IJC built up to overcomc the adhesion (11’1tit> lung tissncs. T~IIS, onc(’ 111~ I*aI( is ~1, the operator need only adjust, t.h(a maLchinc for IJIWIJCI* PS JJallsion of the I1mp. Spont,aneoiw rcspirat,ion in 1lrtl infant usunll~ocy:tlrS

wit.llin

This

il

wiuscitatoi*

stet.ric

and

nursing

i’cw

minllt.es, is

so

staff

Oftt311

ill

:I

ft*TV

S(‘fTIII~lS.

simple iI1 it s O~JC~YilliOlt 1ll;ll the enl.iry (illIJaw tJcen 1 rained iIr ii s llsc in il very shorl knowledge ncrdcd i o opc~ral e the apparatus is of’ tlic mcchanisru of twpirat~ioii. Wtr frrl

I inlc. The only cJssentia1 a practical understanding that any individual who understands the fIlndi~lncrlt,als of respiration and who has learncld how to adjust the> t WJ co~llx~~l knobs on the machine can

give

artifirial

respiration

to

tliv

IwwlJc~ra

in I’ant

with

complct

c

safety. SUkIMAR1

1. The I)ann resuscitator is a safe, eficient, positive pressure respirator. 2. It is simple and virtually foolprooli in design, having only two controls. 3. The rate and volume of respiration arc independently adjust cd to the physiologic needs of the infant. 4. Once adjusted the machine is entirely automatic. Its rhythmic, gentle insufflations simulate natural respiration. Exhalation oceut’s spontaneously. 5. The attached aspirator may be used before full delivery of the infant and should always be used before starting resuscit,ation. In use, it may be readily alternated with the resuscitator. 6. The simplicity of this machine ma.kes it easily operated by almost anyone.

REYNOLDS:

CORRELATING DATA FROM MENSTRUSL

We are indebted to Mr. Morris Dann (73.5 Thornhill Drive, sib=er and manufacturer of this resuscitator for his technical Dr. M. 8. Biskind of New York C&y for his editorial assistance of this manuscript.

CYCLES

151

Cleveland, O.), decooperation, and t,o in the preparation

REFERENCES 1. Eastman, N.: A&L J. OBST. & GYNEC. 40: 647, 1940. 2. Kreiselman, J.: A&f. J. OBST. & GYNEC. 39: 888, 1940. 3. Lund, C. J.: AX J. OBST. & GYNEC. 41: 934, 1941. 10465 CARNEGIE AVEXE 7016 EUPLID AVENUE

METHOD

FOR CORRELATING DATA FROM MENSTRUAII CYCLES OF DIFFERENT LENGTHS A SIMPLE NOMOGRAPHIC PROCEDURE

(F~rmn

the

SAnluEL R. M. RETKOLDS,

PH.D., BALTIMORE,

MD.

Department

Cwnwgie

of

of

Embryology,

Institution

?T’nskingtm)

I

N CLINICAL and laboratory investigations of the menstrual cycle, one is confronted with the problem of bringing together data from cycles, which though normal in every respect, differ greatly from each other in length. Thus, an observation made on the fifth day of a. cycle of twenty-four days in total length may not be compared, on the basis of

Fig. l.-Nomogram for determining the percentile value of any day of a menstrual cycle, counting back from the onset of the next menstrual period. To be used for cycles twenty to forty days in duration. See text for description and use of this device.

any known sequence of physiologic events, with observations made on the fifth day of a cycle thirty-four days in length. One is tempted to arbitrarily disregard cycles outside a given range of duration, or to try to discuss a group of miscellaneous data on the basis of a figurative twenty-eight-day cycle. The simple device proposed in this note is no less empirical than the foregoing methods, but it possesses the merit of