Carbon Monoxide Poisoning In Children .pdf


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Symptom severity is dependent on the acuity of the
exposure and host factors and is more pronounced
with exercise or other exertional activities because
of an increased demand for oxygen.19 CO poisoning
should be suspected in all fire victims and considered in children with known sources of exposure.

The most common symptoms of mild to moderate CO poisoning in adults and children are headache and nausea/vomiting.35,49,51 Other common
symptoms are dizziness, lightheadedness, confusion, fatigue, chest pain, and shortness of breath.71
Generally, it has been described that mild CO
intoxication (< 20% COHb) produces headache, mild
dyspnea, myalgias, visual changes, and confusion.
Moderate poisoning (20%-40% COHb) is associated
with drowsiness, lightheadedness, vomiting, dulled
sensation, dizziness, shortness of breath, and chest
pain. Severe poisoning (> 40% COHb) manifests as
weakness, lethargy, incoordination, and short-term
amnesia. There may be vital sign instability, and
cardiovascular and neurologic collapse is imminent. Above 60% COHb, patients may be comatose,
suffer convulsions, and die.35,36,72 Nonetheless, a
2012 review of 1323 patients referred for HBO in
the Undersea and Hyperbaric Medical Society/
CDC CO Poisoning Surveillance System found that
symptoms alone cannot be accurately correlated to a
given COHb level and that there is a large spectrum
of possible presenting symptoms.71 (See Table 1,
page 8.) Given the lack of specificity of symptoms,
both presentation and COHb level should be taken
into account when determining the severity of CO
poisoning.

Young children may lack the ability to explain
symptoms they are experiencing. While older children manifest symptoms similar to adults, symptoms in infants might be as vague as irritability and
poor feeding. In a case series of 30 children with
severe CO poisoning, disturbance of consciousness
was found to be the most common symptom in
young children and infants.66

Exposure History
Potential sources for CO exposure should be assessed in all children with nonspecific symptoms,
especially in the absence of fever. It is important to
ask about where and when symptoms began and
whether there is a pattern to the symptoms. For
example, did symptoms begin while in a motor vehicle? Are the symptoms present at home but not at
school? Or are the symptoms worse in the morning?
Practitioners might inquire whether a residence recently began using a combustible-fuel heating source
(ie, kerosene heater, wood stove, fireplace, natural
gas appliance, Sterno® unit, or central heating system). Close contacts who have symptoms or known
CO poisoning should cause a clinician to suspect a
common exposure. The sudden death or illness of
September 2016 • www.ebmedicine.net

household pets may be a harbinger for human CO
poisoning and provide a clue of gas exposure.73-75

Most exposures occur at home rather than at
work or school.3 In a prospective study of 483 patients, the most common time period for CO poisoning presenting as headache was between midnight
and 10:00 AM.76

Some helpful questions that might reveal a potential CO exposure include:
• Are there any pets at home? Are they acting
normally?
• Are other close contacts having similar or seemingly unrelated symptoms?
• Is there a daily pattern to the symptoms?
• Has the child had a fever? (Not usually present
with CO poisoning)
• Where was the child when the symptoms began?
• Have household heating equipment, generators,
or other appliances been recently turned on?
• Do you have a CO detector at home? When was
it last tested? (Ideally, once per month)
• When was the last time the household heating
system was inspected? (Ideally, annually)
• Was noninvasive CO-oximetry performed by
EMS in the field?

Physical Examination
A thorough and complete physical examination/
secondary survey is warranted in suspected CO poisoning and should focus on assessing for comorbid
conditions and signs of organ dysfunction. Special
attention should be given to the cardiopulmonary
and neurologic examination, which may help a
clinician decide on acute interventions and whether
transfer to an HBO center is warranted.

Although there is a trend for more-severe poisoning to be associated with vital sign abnormalities,
there are no abnormal vital sign patterns specific to
CO poisoning.77 A retrospective case series of 476 patients aged > 16 years with CO poisoning found that
68% of patients with COHb levels > 20% had normal
vital signs.77

A complete cardiopulmonary assessment should
be performed as described in the primary survey
and repeated with the secondary survey. CO can
have direct toxic effects on the heart, leading to dysrythmias78,79 and myocardial dysfunction.80,81 Serial
cardiovascular examinations should be performed
to assure adequate perfusion to peripheral tissues. A
careful respiratory examination in combination with
radiographic imaging helps find contributing factors
to respiratory insufficiency. Victims of smoke inhalation are at risk for pneumonitis or acute respiratory
distress syndrome. Trauma victims may have rib
fractures, pulmonary contusions, hemothoraces, or
pneumothoraces. Obtunded patients may have aspirated. Patients with asthma may have contributing
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