Face Masks Defended

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PEDIATRICS

Vol. 58 No. 4 October

1976

621 COMMENTARIES

(CONTINUED)

Face

Masks

Defended

Pediatricians caring for the newborn are

partic-ularly aware of unexpected deleterious outcomes

of well-intentioned therapy. Oxygen,

chloram-phenicol, sulfadiazine, and continuous positive

airway pressure are examples. Elsewhere in this

issue Pape et ‘ suggest that intermittent

posi-tive-pressure ventilation provided by a

tight-fitting face mask in low-birthweight infants is yet

another example. They observed a 30% incidence

of significant intracerebellar hemorrhages in

infants so treated (groups A and D). Such

hemor-rhages were seen in 10% of babies who were

ventilated by an endotracheal tube rather than by

mask (groups B and C), and were not seen in their

13 nonventilated babies (group E). The authors

propose that the combination of severe

distor-tional forces produced by the tight-fitting mask

and the buffeting of the posterior occiput by the

bruising intermittency of the pressure impulse of

the artificial ventilator is causally related to these

intracerebellar hemorrhages. Mechanistically,

they envision direct contusion of the cerebellar

veins by the compressive band or by the

buffet-ing, ischemic stasis of the veins from the occlusion

of the sagittal sinus by the distortion of the head,

or such marked venous congestion that the

increased transluminal pressure of the small veins

of the cerebellum ruptures them. This form of

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FIG. 1.The occurrence of significant cerebellar hemorrhage in relation to degree of prematurity and length of survival. Crosses, data of Pape et al. (20 cases); circles, data of Grunnet (24 cases,

personal communication); triangles, i author’s data (9 cases).

at Viet Nam:AAP Sponsored on September 8, 2020 www.aappublications.org/news

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D:r

Survival

29 30 31 32.. 33 31- 35 3 37 38 3? ),‘40

Weeks of gestat-ion

co a o zi o 0 0 0 0 0 0 0

Fmc. 2. The incidence of significant cerebellar hemorrhages in 78 consecutive autopsies at Magee-Womnens Hospital, Pittsburgh . Circles, no significant cerebellar hemorrhage; crosses,

significant cerebellar hemorrhage.

622

FACE MASKS DEFENDED

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therapy has been discontinued at the Neonatal

Intensive Care Center in Toronto.

The statement that the causal factor is a

tight-fitting face mask is unproven and, it is likely,

incorrect. Groups B and C of Pape et a!. are

comparable in gestation, survival time, and mode

of exposure to ventilation. Groups A and D are

quite different from each other and should not

have been combined into a single group. A

consists of small (780 gm), young (27 weeks’

gestation), short-lived (5 days) infants exposed to

the ventilator via the face mask for a short

interval (three days). There is no demographically

comparable group. Group D infants were larger (1,000 gin), older (29 weeks’ gestation),

longer-lived (10 days), and were exposed to the ventilator

via the face mask for a longer period of time

(eight days). There is no group comparable to D,

for it is the longest lived of all four groups.

As reported by Helmrath et al.,2 this lesion was

absent in the autopsy material of 70 infants

weighing less than 1,500 gui at birth, most of

whom were ventilated by face mask in 1967 and

1968.#{176}The tight-fitting face mask was held in

place by two anesthesia straps rather than a single

band and a folded diaper was placed over the

occiput. Their length of survival was short, and

the survival rate was poor (8%).

Grunnet et al. : have also recently reported

cerebellar hemorrhages in markedly premature

infants (median, 27 weeks’ gestation). The

frequency of this lesion in their autopsy

popula-tion less than 32 weeks’ gestation was 14%, similar

#{176}Theneuropathologic muaterial from the autopsies of the population reported by Helmrath et al. was recently

reexam-med by the staff of the Department of Neuropathology at the

University of Washingtomi, through the courtesy of Drs.

Alvord and Hodson. No significant intracerebellar

hemor-rhages were found omi this reexamination.

(3)

COMMENTARIES 623

to the 19% of infants weighing less than 1,501 gm

reported by Pape et a!. These children were not

exposed to the face mask; all were intubated for

ventilation.

Review of 78 consecutive autopsies from the

Neonatal Intensive Care Unit of the

Magee-Womens Hospital of the University of Pittsburgh

School of Medicine between July 1, 1975, and

May 30, 1976, revealed nine patients with

signif-icant intracerebellar hemorrhage (19% of infants,

of 32 weeks’ gestation or less!). Face mask

venti-lation was not used in Pittsburgh; all of these

infants were ventilated by endotracheal tubes. All

but one of the infants with intracerebellar

hemorrhages also had cerebral subependymal

hemorrhages and idiopathic respiratory distress

syndrome. The one exception was a stillborn

infant of 25 weeks’ gestation.

The lesion seems most closely related to

gesta-tional age and length of survival (Fig. 1 and 2).

Significant intracerebellar hemorrhages are most

common below 30 weeks, rare between 30 and 32

weeks, and essentially disappear above 32 weeks.

Infants of less than 28 weeks’ gestation need not

survive long; infants of 29 to 32 weeks’ gestational

age must survive at least several days to develop

the lesion.

Small intracortical cerebellar hemorrhages are very common in premature infants (50% of suit-ably premature brains).4’5 The intracerebellar

hemorrhages reported by Pape et al. are of

significantly greater mass than previously noted. Logically, the insignificant intracerebellar

pete-chiae may serve as the nidus for the subsequent

development of the significant hemorrhages.

Very premature babies formerly survived very

short periods of time; such babies often now survive for periods of days rather than hours. Just as it takes some time to produce cerebral

sube-pendymal cell plate hemorrhages (6 to 12 hours

before the incidence markedly increases), so does

it take time to produce cerebellar hemorrhages.

J

ust as the poorly supportive cerebral subepen-dymal germinal matrix is implicated in subepen-dymal hemorrhage, so is the poorly supportive

cerebellar subpial germinal matrix implicated in

cerebellar hemorrhages. Almost all infants with

cerebellar hemorrhage have intracerebral

sube-pendymal hemorrhages and respiratory distress syndrome.

Prolonged survival of markedly premature

infants has increased the incidence of this

hereto-fore rare lesion in pediatric neuropathology. It is

now recognized in at least three centers, two of

which do not use mask ventilation (Salt Lake City

and Pittsburgh). We believe the mode of

ventila-tion is not etiologically important bitt the

dura-tion of survival and degree of prematurity are.

ROBERT

M.

SHUMAN,

M.D.

THOMAS

K.

OLIVER, JR.,

M.D.

Departments of Pathology and

Pediatrics,

University of Pittsburgh School

of Medicine, and

Children’s Hospital of Pittsburgh

Pittsburgh, Pennsylvania 15213

REFERENCES

1. Pape KE, Armstrong DL, Fitzhardinge PM: Central

nervous system pathology associated with mask

ventilation in the very low birthweight infant: A

new etiology for intracerebellar hemorrhages. Pediatrics 58:473, 1976.

2. Helmrath BA, Hodson WA, Oliver TK Jr: Positive

pressure ventilation in the newborn infant: The use

of a face mask. J Pediatr 76:202, 1970.

3. Grunnet MI, Shileds WD: Cerebellar hemorrhage in a

premature infant. J Pediatr 88:605, 1976.

4. Schwartz P, Fink L: Morphologie und Entstehung der

Geburtstraumatischen Blutungen im Gehirn und

Sch#{228}deldes Netmgeborenen. Z Kinderheilkd 40:427, 1927.

5. Friede RL: Developmental Neuropathology. New York,

New York, Springer-Verlag, 1975, p 30.

Theophylline

in asthma

In this issue of Pediatrics, Ellis et al.’ have a

study of the pharmocokinetics of theophylline, a study which is 40 years overdue and which was

technically feasible 25 years ago. They show that

children are not “little adults” in that the dosage

of theophylline and the dosing intervals in

chil-dren cannot be based on adult studies. Their work

shows that theophyllmne has a significantly shorter

biologic half-life in children, and that intersubject

variation is far greater, with a range of 1.4 to 7.8

hours. Thus, compared to adults, children tend to require relatively larger amounts of theophylline

per kilogram of body weight per day, and the

doses may have to be given at shorter intervals of

time. These findings place an obligation on the

(4)

1976;58;621

Pediatrics

Robert M. Shuman and Thomas K. Oliver, Jr.