To the Editor,
As a pediatric anesthesiologist, I read the Clinical Report in the
December 2005 issue of Pediatrics entitled “Cardiovascular Health
Supervision for Individuals Affected by Duchenne or Becker Muscular
Dystrophy” with great interest.1 Strong points in the article included
emphasizing the frequent absence of classical symptoms of cardiac failure
and the need for cardiac evaluation including echocardiography prior to
major surgery. Also, there should be immediate availability of a
cardioverter-defibrillator to treat life-threatening dysrhythmias in the
operating room.
I am concerned over the statement that inhaled anesthetics are
“known” to cause a “hypermetabolic state” and “should be avoided” in these
patients. Although there have been reports of clinical MH-like events and
positive in-vitro contraction tests in patients with dystrophinopathies,2
the incidence of this complication is unknown. Whether DMD or BMD
predispose to MH or MH-like episodes with the use of inhaled agents alone
is controversial and far from firmly established in the literature.
Specific warnings against the use of inhaled agents in dystrophinopathy
patients are not found in the package insert information for volatile
agents.
Careful examination of the paper by Breucking et al.3 (referred to in
the statement as supporting the avoidance of inhaled agents in patients
with muscular dystrophies) reveals that 12 of 14 patients having
complications (in which complete anesthetic data was available) received
succinylcholine along with an inhaled agent. Succinylcholine is a well-
established cause of rhabdomyolysis in patients with myopathies. Indeed,
major cardiac complications have been reported with the use of intravenous
anesthesia alone in DMD patients.4,5 Some authors believe that the
incidence of MH in patients with DMD is the same as that in the general
population and that inhaled agents should be used in these patients.6,7
The issue is further complicated by the fact that dystrophin deficient
patients have altered muscle cell calcium metabolism which potentially may
be a cause of false-positive in-vitro MH susceptibility testing.2
Goresky and Cox8 presented both sides of the controversy in a 1999
editorial. They concluded by urging anesthesiologists to consider being
more cautious in their use of inhaled agents in dystrophinopathy patients,
instead relying on the intravenous agents propofol, remifentanil, and
midazolam. Subsequent to that editorial, reports of the propofol infusion
syndrome in both ICU and operating room environments have been
accumulating.9,10 Unfortunately, we do not know the relative risk of this
complication with that of hypermetabolism and rhabdomyolysis in the
dystrophinopathy patient receiving inhaled agents.
Therefore, whether or not potent volatile anesthetics should be
routinely avoided in DMD and BMD patients is still open to debate. It is
my hope that the recommendation to avoid prolonged use of inhaled agents
in patients with DMD or BMD as published in Pediatrics by the Section on
Cardiology and Cardiac Surgery are not construed as standards of care for
anesthesiologists, particularly without their explicit involvement in the
preparation of this statement.
Sincerely,
Samuel Golden, M.D., FAAP
Comer Children’s Hospital
Department of Anesthesia and Critical Care
University of Chicago
Conflict of Interest:
None declared