Paul G. Harch, M.D., Jamie Deckoff-Jones, M.D., Richard A.
Neubauer, M.D., Hyperbaric Medicine Physicians See authors'
affiliations at end of article.
Pediatrics Online, 12 Feb 2001 [Response]
LOW PRESSURE HYPERBARIC OXYGEN THERAPY FOR PEDIATRIC BRAIN
INJURY, A MINIMAL RISK MEDICAL TREATMENT 12 February 2001
Paul G. Harch, M.D., Jamie Deckoff-Jones, M.D., Richard A.
Neubauer, M.D., Hyperbaric Medicine Physicians
LOW PRESSURE HYPERBARIC
OXYGEN THERAPY FOR PEDIATRIC BRAIN INJURY, A MINIMAL RISK MEDICAL
TREATMENT RESPONSE TO NUTHALL ARTICLE
read the recent contribution to your esteemed journal by Nuthall, et
al with extreme disappointment. Unfortunately, this article distorts
the true complication rate of low-pressure hyperbaric oxygen therapy
(LPHBOT) in the treatment of pediatric neurological conditions.
Noticeably missing from the paper is an estimate of the frequency
with which these complications occur. Without such perspective, this
article misleads the medical community and fuels the unfounded fear
that LPHBOT is dangerous for children with cerebral palsy, when in
fact it is both safe and an extremely useful adjunctive therapy.
The first case mentioned in the article, vomiting with
aspiration, is a complication that can occur in an adult or
pediatric patient with gastro esophageal reflux in many medical
settings, hyperbaric or normobaric. Unfortunately, the article does
not give enough information for a critical appraisal of the
patient's care. Air swallowing at anytime, but especially during and
HBO treatment, can lead to gastric distention, which can worsen, on
ascent. It is easily avoided by simple venting in patients with
feeding tubes. The "tight-fitting" oxygen hood implies neck
constriction, but the hood used in multiplace chambers throughout
the United States and Canada in fact utilizes a comfortably fitting
latex neck dam. A competent attendant can easily remove the hood if
needed and suction should be available in the chamber. Aspiration is
a rare complication of HBOT, but does occur in the ill adult
population. To put the matter in perspective in the pediatric
population, since the first HBOT for a CP child in North America in
1992 (2) authors PGH and RAN have logged over 35,000 treatments on
brain-injured children without a single case of primary aspiration
or air embolism. Approximately 7,000 of these treatments were
performed on an IRB-approved protocol. The point is that this case
report represents a very rare indeed, and most likely a completely
avoidable one in a setting of adequate care. We believe the slight
risk is acceptable given the positive responses in the vast majority
The second case is an unfortunate example of an acutely ill
child who should have been denied treatment by proper pre-treatment
evaluation the day of the accident. The authors attribute the
child's cerebral infarct to an oxygen embolism caused by primary
arterial bubbles during decompression or venous oxygen bubbles
breaching the pulmonary filter or a patent foramen ovale (PFO). In
our opinion, this diagnosis is exceedingly unlikely, the mechanisms
suggested by the authors nearly impossible to account for their
diagnosis, and their argument not supported by the references cited.
Primary arterial bubbles of any gas are only seen in explosive
decompressions (3). No such scenario is described in the article.
Primary venous bubbles occur in almost all decompressions,
but oxygen decompression sickness, and presumably bubbles, have only
been documented in animals at 3.53 atmospheres absolute (ATA) of
oxygen (4) which is over two times the oxygen exposure of this
patient. Furthermore, venous bubbles of any gas will form in
proportion to the gas load of the dive. This patient's dive, 1.5
ATA, is a very shallow exposure, which would produce minimal, or no
bubbles. Venous bubbles that do form during decompression have been
measured to be mostly 19 to 180 microns with some larger bubbles up
to 700 microns (5). While it is possible for the bubbles to breach
insulted lungs (Para influenza induced respiratory failure) or
proceed through a PFO to cause an infarct they would have to
selectively coalesce and be retained in the much larger MCA. This is
highly unlikely, given the argument above and the fact that oxygen
bubbles should be readily metabolized, and hence transient.
Lastly, the two references cited to justify two of the
proposed mechanisms don't apply this case; both are articles on
iatrogenic air embolism (6, 7) and/or pulmonary barotrauma (6). In
addition, the Muth article (6) contradicts the authors' mechanisms
by stating, "Cerebral arterial gas embolization typically involves
the migration of gas to small arteries (average diameter, 30 to 60
microns)." The MCA is much larger in a 10-month-old child. Muth
further states that all patients with clinical symptoms of arterial
gas embolism should receive recompression treatment with hyperbaric
oxygen. To attribute this child's cerebral infarct to an oxygen
embolism by any mechanism is nearly impossible. More likely, this
infarct was the result of a vasospastic event, fat embolism from
infected marrow, or some other etiology related to the child's
Patient safety is paramount and we believe that physician
attended HBOT is mandatory.
The Nuthall article begs the greater question of why patients
are driven to non-physician attended facilities to obtain medical
treatment. The British Columbia College of Physicians and Surgeons
(8) and an ex-president of the Undersea and Hyperbaric Medical
Society (UHMS) purportedly speaking for the UHMS (9) have now
forbidden and threatened doctors, respectively, should they treat
non-UHMS approved pediatric neurological disease with HBOT. This is
a dangerous and intolerable precedent. Off-label use of any FDA
approved device or drug by a qualified ethical physician constitutes
the legal practice of medicine. It is to the medical professions
embarrassment that families are forced to seek care from facilities,
which may be ill equipped or staffed by personnel who lack medical
The call for a randomized controlled trial, while desired,
strikes a loud and clear double standard. There exists far more
evidence to support cerebral palsy as a UHMS HBOT "accepted
indication"(10) than existed for cerebral abscess, the last
indication added to the list in 1996. In addition, reviews of the
accepted indications list by author PGH in 1998 for a presentation
at the Advanced Topics Course in Hyperbaric Medicine (11), by
evaluators for the Calgary Regional Health Authority in 1999 (12),
and Blue Cross/Blue Shield in 2000 (13) found that as many as 6 -7
of the accepted thirteen diagnoses are not supported by either
controlled clinical trials and/or adequate research. The statement
by the Nuthall article that neither they nor the UHMS can recommend
HBOT for CP in the absence of randomized (Nuthall) controlled (UHMS
and Nuthall) clinical trials is inconsistent.
In conclusion, we
must correct the Nuthall article's frightening implication and
inform the medical community that low-pressure HBOT for pediatric
brain injury is a very low risk medical treatment, supported by our
combined experience of greater than 35,000 patient treatments.
Paul G. Harch, M.D.
Clinical Assistant Professor
Section of Emergency and Hyperbaric
LSU School of Medicine
Jamie Deckoff-Jones, M.D.
Great Barrington, Massachusetts.
Richard A. Neubauer. M.D.
- Nuthall G, et al. Electronic article: Hyperbaric Oxygen
Therapy for Cerebral Palsy; Two Complications of Treatment.
- Harch PG, et al. HMPAO SPECT Brain Imaging and Low Pressure
HBOT in the Diagnosis and Treatment of Chronic Traumatic,
Ischemic, Hypoxic, and Anoxic Encephalopathies. Undersea Hyper
- Hills BA. Decompression Sickness, Volume 1: The Biophysical
Basis of Prevention and Treatment. John Wiley and Sons, New York,
- Vann RD, Thalmann ED. Chapter 14, Decompression Physiology,
and Practice, p.396. The Physiology and Medicine of Diving, 4th
Edition. Editors Bennett and Elliott. W. B.Saunders Co, Ltd.,
- Hills BA, Butler BD. Size Distribution of Intravascular Air
Emboli Produced by Decompression. Undersea Biomed Res,
- Muth CM, Shank ES. Gas Embolism. New England Journal of
- Murphy BP, et al. Cerebral Air Embolism Resulting from
Invasive Medical Procedures. Ann Surg, 1985;201:242-245.
- Locklear KR. College of Physicians and Surgeons of British
Columbia Announce Standards for Non-Hospital Medical Hyperbaric
Oxygen Facilities. Hyper Med Today, 2000;1(2):20-21.
- Kindwall EW. Research in Hyperbaric Medicine. Hyper Med
- Harch PG. McGill University Pilot Study of HBOT in the
Treatment of Spastic Diplegia Cerebral Palsy. Hyper Med Today,
August-September, 2000;1(3):44-45, and 49.
- Harch PG. Hyperbaric Oxygen Therapy in Acute Neurological
Indications. 7th Annual Advanced Topics Course in Hyperbaric
Medicine, Richland Memorial Hospital, Columbia, South Carolina.
April, 1998. Available in text and on videotape from the
Department of Hyperbaric Medicine, Richland Memorial Hospital.
- Mitton C, Hailey D. Health Technology Assessment and Policy
Decisions on Hyperbaric Oxygen Treatment. Inter J Tech Assess in
Health Care, 1999;15(4):661-70
- Hyperbaric Oxygen Therapy for Wound Healing, Part I. TEC
Assessment Program, August, 1999;14(15):1-34. Available from Blue
Cross Blue Shield Association.