Chapter 127

2094 PART 6 ■ Specific Considerations
In addition to respiratory, medication, equipment, and cardiovascular
causes, cardiac arrests related to an occult underlying
disease have been reported. Unexpected cardiac arrests after
succinylcholine administration in infants and children with occult
myopathies are mainly related to hyperkaliemia. 30–33 Between 1990
and 1993, 25 unexpected cardiac arrests in apparently healthy
children scheduled for minor surgery were reported to the
Malignant Hyperthermia Association of the United States and the
North American Malignant Hyperthermia Registry. 30 Twelve
patients out of 25 had unrecognized myopathy (Duchenne dystrophy
in 8 and unspecified myopathy in 4). Restrictions on
succinylcholine use would have prevented 64% of arrests and 60%
of deaths. Surprisingly, no cardiac arrests resulting hyperkalemia
caused by rhabdomyolysis following the use of inhalation agents
and/or succinylcholine in children with undiagnosed myopathy
were reported in the two POCA registries. However, undiagnosed
myopathies remain a problem despite a reduced used of succinylcholine
after the Food and Drug Administration (FDA) warning
in 1994. Unexpected cardiac arrest related to rhabdomyolysis with
hyperkalemia have been reported after an uneventful anesthesia
without administration of succinylcholine in children with
unrecognized muscular dystrophy. 34–37 The dilemma of providing
anesthesia of the undiagnosed child was recently reviewed. 38,39
Basically there are two families of diseases that deserve consideration,
the muscular dystrophies and the mitochondrial
myopathies. As already discussed, it is commonly accepted to
avoid the use of succinylcholine and volatile agents in children
with known neuromuscular disorders, despite the risk of a patient
with neuromuscular disorder to have malignant hyperthermia
or rhabdomyolysis from exposure to a volatile anesthetic is
estimated to be less or equal to 1.09%. 40 Conversely, it is now
suggested that patients with known mitochondrial disease should
not receive propofol owing to the lipid carrier of propofol may
have adverse effect on fatty acid oxidation and mitochondrial
respiratory chain function, and therefore put patients with
mitochondrial disorders and closely related carnitine deficiency
syndromes at risk for a clinical scenario similar to propofol
infusion syndrome. 41–43
Cardiac arrests related to underlying undiagnosed cardiac
disease (viral myocarditis, long-QT syndrome, and abnormal
coronary artery) have also been reported in children. 44–46
To summarize old and recent data on incidence and etiologies
of pediatric cardiac arrests, one have to stress that the highest
incidence is still observed in infants of less than 1 year of age, in
emergency, in patients with cardiac diseases and other comorbidities.
There is a tendency for a relative reduction in respiratoryand
medication-related cardiac arrests together with a relative
increase in cardiovascular-related cardiac arrests. Finally equipment
is responsible for a stable proportion of such critical events.
The next challenge will be to reduce some avoidable causes of
cardiovascular cardiac arrests such as hyperkalemia following
massive transfusion and adequate compensation of acute hypovolemia,
and to anticipate carefully the management of children
with underlying known or unknown diseases.
ANESTHESIA-RELATED MORBIDITY
Incidence
Many studies have reported an increased morbidity in young
pediatric patients compared to older children and young adults.
TABLE 127-4. Risk Factors for Perioperative
Complications in Children 21
No.
Rate of Complications
Anesthesias (per 1000 Anesthesias) Significance
ASA Physical Status:
I 36,903 0.4 P < .001
II 1,461 3.4
III 518 11.6
IV, V 122 16.4
No. coexisting diseases:
0 36,544 0.5 P < .001
1 3,064 1.3
2 490 4.1
≥3 142 21.1
Previous anesthetic:
no 25,517 0.5 P < .05
yes 11,343 1.1
Duration of preoperative fasting, h:
8 34,067 0.6
Emergency:
no 33,391 0.5 P < .05
yes 5,918 1.5
Two large studies performed in the 1980s in France and Canada
reported a much higher incidence of severe complications in
infants compared to older children. 15,21 In the old French survey
performed in 1982, 21 the rate of perioperative complications
increased significantly with the young age, the ASA score, the
number of coexisting diseases, emergency, and reduced duration
of preoperative fasting (Table 127–4). In the Canadian survey 15
performed between 1982 and 1987, the incidence of major complications
was much higher in neonates (23.8%) than in infants
(5%) and older children (3%).
The most recent epidemiologic study on perioperative morbidity
was published by Murat, 19 and its results are summarized
in Table 127–5. Over a total of 24,165 general anesthesias performed
between January 2000 and June 2002, 724 incidents were
reported in the operating room (31/1000 anesthetics) and 1105 in
the postanesthetic intensive care (PACU) (48/1000 anesthetics).
In comparison with the study of Cohen published in 1990, 15 the
incidence of most complications has dramatically decreased. This
may at least partially be attributed to the availability of pulse
oximetry, capnography, the laryngeal mask airway, sevoflurane,
short-acting muscle relaxants and propofol, and by better training
and knowledge of pediatric anesthesiologists. For example, the
incidence of postoperative laryngospasm is nowadays lower by a
factor of more than 20.
However, the main messages remain the same:
The child less than 1 year of age is at increased risk
Respiratory problems are the cause of more than 50% of the
complications reported
There are more complications in the postanesthesia care unit
(PACU) but they are usually less severe than in the operating
room
The incidence of complications increases with the ASA score and
the number of coexisting problems