High carboxyhemoglobin level without acute or chronic findings

Does age affect presenting symptoms in children with carbon monoxide poisoning?

OBJECTIVE

Previous studies have reported on a link between carboxyhemoglobin (COHb) levels and the severity of presenting findings. However, studies on pediatric populations evaluating the effect of age on presenting symptoms are severely lacking. The aim of this study was to investigate the presence of any link between age and presenting symptoms in children with carbon monoxide (CO) poisoning.

METHODS

This retrospective study was undertaken in Ankara Children's Hematology and Oncology Hospital, a tertiary care center, between January 2007 and March 2010. The medical records of patients aged between 0 and 16 years with a confirmed diagnosis of CO poisoning, defined as the presence of a COHb level of more than 5%, were evaluated. Relevant information such as age, sex, source of CO, coaffected family members, month of presentation, time of presentation and presenting symptoms, duration of oxygen treatment in the emergency department, need for admission to an inpatient ward or intensive care unit, Glasgow Coma Scale scores, and administered treatments during follow-up was recorded for each patient on preprepared forms. For the purpose of comparison, patients were divided into 2 groups based on COHb levels (group 1, 5%-25%; group 2, >25%). Comparisons were also made after dividing patients into 3 age groups: infants (0-3 years), preschool and early-school children (4-8 years), and adolescents (9-16 years).

RESULTS

The records of 261 patients were deemed sufficient for inclusion in the final analysis, 149 (57.1%) of which were female, and 112 (42.9%) were male, with a median age of 7.0 years (range, 1 month to 16 years) and a mean COHb level 16.9% (SD, 7.8%). Two hundred eighteen patients (83.5%) had a COHb between 5% and 25% on presentation, whereas the remaining 43 patients (16.5%) had a presenting COHb of greater than 25%. Neurologic symptoms such as headache, syncope, seizures, and confusion were encountered more frequently in the COHb greater than 25% group compared with the group with 5% to 25% COHb levels, with adolescents having more severe symptoms than do younger patients.

CONCLUSIONS

In this study, we managed to demonstrate the presence of more severe symptoms in patients with a COHb level of 25% or greater. Further analysis revealed that severe symptoms were more pronounced in adolescents and that the severity of symptoms increased with age.

Toxicity Associated with Carbon Monoxide

Carbon monoxide is an insidious poison that accounts for thousands of deaths each year in North America. Clinical effects maybe diverse and include headache, dizziness, nausea, vomiting,syn-cope, seizures, coma, dysrhythmias, and cardiac ischemia. Children, pregnant women, and patients who have underlying cardiovascular disease are particularly at risk for adverse out-comes. Treatment consists of oxygen therapy, supportive care, and, in selected cases, hyperbaric oxygen therapy.

Carbon monoxide poisoning

CO is an ubiquitous poison with many sources of exposure. CO poisoning produces diverse signs and symptoms that are often subtle and may be easily misdiagnosed. Failure to diagnose CO poisoning may result insignificant morbidity and mortality and permit continued exposure to a dangerous environment. Treatment of CO poisoning begins with inhalation of supplemental oxygen and aggressive supportive care. HBOT accelerates dissociation of CO from hemoglobin and may also prevent DNS. Absolute indications forHBOT for CO poisoning remain controversial, although most authors would agree that HBOT is indicated in patients who are comatose or neurologically abnormal, have a history of LOC with their exposure, or have cardiac dysfunction. Pregnancy with an elevated CO-Hgb level(>15%-20%) is also widely, considered an indication for treatment.HBOT may be considered in patients who have persistent symptoms despite NBO, metabolic acidosis, abnormalities on neuropsychometric testing, or significantly elevated levels. The ideal regimen of oxygen therapy has yet to be determined, and significant controversy exists regarding HBOTtreatment protocols. Often the local medical toxicologist, poison control center, or hyperbaric unit may assist the treating physician with decisions regarding therapy.

Carbon monoxide poisoning

CO is an insidious poison with many sources of exposure. CO poisoning produces diverse signs and symptoms, which often are subtle and can be misdiagnosed easily. Failure to diagnose CO poisoning may result insignificant morbidity and mortality and allow continued exposure to a dangerous environment. In the ED, a high index of suspicion must be maintained for occult CO exposure. Headache, particularly when associated with certain environments, and flulike illness in the wintertime with symptomatic cohabitants should raise the index of suspicion in the ED significantly for occult CO poisoning. Emergency treatment of CO poisoning begins with inhalation of supplemental oxygen and aggressive supportive care. HBOT accelerates dissociation of CO from hemoglobin and may prevent DNS. Absolute indications for HBOT for CO poisoning remain controversial, although most would agree that HBOT is indicated in patients who are comatose, are neurologically abnormal, have a history of loss of consciousness with their exposure, or have cardiac dysfunction. Pregnancy with an elevated CO-Hgb level (>15-20%) also is widely considered an indication for treatment. HBOT may be considered in patients who have persistent symptoms despite NBO, metabolic acidosis, abnormalities on neuropsychometric testing, or significantly elevated levels. The ideal regimen of oxygen therapy has yet to be determined, and significant controversy exists regarding HBOT protocols. The emergency physician may be confronted with the difficult decision regarding disposition and even transfer to a hyperbaric facility. Often the local medical toxicologist, poison control center, or hyperbaric unit can assist the emergency physician with the decision-making process.

[Measurement of carbon monoxide in expired breath in prehospital management of carbon monoxide intoxication]

INTRODUCTION

Carbon monoxide detectors are currently used by the French prehospital medical teams. These detectors can also be used to measure expired breath carbon monoxide concentration. The interest of this measurement has never been studied.

OBJECTIVE

To evaluate interest of expired breath carbon monoxide concentration measurement in the management of prehospital carbon monoxide intoxication.

STUDY DESIGN

Patients with carbon monoxide poisoning were included during 1998.

PATIENTS AND METHODS

Four levels of clinical severity: no symptom, minor, medium or severe intoxication were defined. Carbon monoxide concentration were measured in the expired breath (COHbe) at the place of the intoxication and in blood samples collected at the place of the intoxication (COHbs) and at the hospital (COHbh).

RESULTS

209 patients were included, 144 had no symptom (55%), the value of COHbe was 11.6 +/- 7.5% (mean +/- DS) and the value of COHbh was 4.9 +/- 3.3%. 91 patients had minor intoxication (35%), the value of COHbe was 16.4 +/- 7.9% and the value of COHbh was 7.1 +/- 4.5%, 21 patients had sever or medium intoxication (8%) the value of COHbe was 26.4 +/- 17.7% and the the value of COHbh was 12.8 +/- 9.3%. Results for COHbh were obtained for only three patients. Relationship between symptoms and expired breath carbon monoxide and relationship between symptoms and carbon monoxide blood concentration on arrival at the hospital were significant (p < 0.05).

CONCLUSION

Measurement of expired carbon monoxide concentration, easy and quick to perform is correlated with clinical severity in carbon monoxide poisoning.

Carboxyhemoglobinemia caused by inhalation of methylene chloride

Spray-paint inhalation, once a common and inexpensive source of drug abuse, is now rare. Newer organic solvents, such as methylene chloride, were thought to decrease the toxicity of aerosol solvents, but they carry unique toxicities of their own. Methylene chloride toxicity is difficult to diagnose, as early symptoms are similar to those associated with many intoxicants; however, a rising carboxyhemoglobin level, despite removal of the patient from the source of exposure, is pathognomonic. In dealing with industrial exposures or organic aerosol abuse, a carboxyhemoglobin level should be part of the initial diagnostic workup, and treatment with oxygen is mandatory until toxicity resolves.