Abstract: Carbon monoxide (CO), a colorless and odorless gas, is one of the common causes of poisoning-related deaths worldwide. CO poisoning can result in hypoxic brain damage and death, but intensive care can improve the likely outcome for critically ill patients....
Carbon Monoxide Poisoning
Clinical Trial – Occult Carbon Monoxide Poisoning Detection by Pulsated Carboxymetry in an Emergency Department
In France, the carbon monoxide is one of the first causes of the accidental poisonings with
approximately 8000 cases a year, among which 500 deaths.
The severe forms are translated by neurological disorders even a coma or the death straight
away. The more insidious forms with a little carboxyhémoglobine level give rise to frustrate
clinical pictures, mimicking flu or intestinal syndromes. The syndrome post–intervallaire
corresponds to the appearance of remote neuropsychiatric disorders of the poisoning. Its
appearance and its gravity are not correlated in the gravity of the initial poisoning,
however the precocity of the treatment tends to decrease its frequency.
Carbon monoxide elimination is made under unchanged form in the expired air. In a spontaneous
way, the half-life in ambient air is of the order of 4 hours. In ventilation in isobaric pure
oxygen, the half-life is shortened at 80 minutes and in hyperbaric oxygen at 23 minutes.
This imposes a fast diagnosis for two reasons:
– For poisonings with low level, the more the investigators wait to measure the
carboxyhémoglobine (HBCO), the more they risk not to detect it.
– The oxygen therapy decreases the duration of the poisoning and thus the tissular
suffering.
Actually the risk is important to pass next to the diagnosis and to let leave a patient
without adapted care and without technical intervention to eliminate the source of the
poisoning.
Presently, to make the diagnosis, the investigators possess the analysis of the blood HbCO by
realization of gas of the venous blood, which are taken in emergencies, but very often a few
hours after the end of the exposure at the source of poisoning, what is translated by a
disappearance of the symptoms and an underestimate of the initial blood HbCO. Since 2005,
MASIMO laboratory commercialize a pulse carboxymètre, the RAD 57, which allows to estimate
the carboxyhémoglobinémie in a not invasive way.
Lot of studies showed the interest of its use in the early screening of carbon monoxide
poisonings, allowing a faster dosage of the blood HbCO, and thus an also faster adapted care.
Clinical Trial – Hyperbaric Oxygen Therapy for Comatose Patients With Acute Carbon Monoxide Poisoning
Carbon monoxide poisoning still places a burden on the healthcare system worldwide. While
oxygen therapy is the cornerstone treatment, the role and practical modalities of hyperbaric
oxygen therapy (HBO) remain controversial. This study aimed at comparing two sessions of HBO
at 2 absolute atmosphere and one session of HBO at 2 absolute atmosphere followed by 4 hours
of normobaric oxygen therapy in comatose adult victims of acute domestic carbon monoxide
poisoning.
Clinical Trial – Hyperbaric Oxygen Therapy for Acute Domestic Carbon Monoxide (CO) Poisoning
Carbon monoxide poisoning still places a burden on the healthcare system worldwide. While
oxygen therapy is the cornerstone treatment, the role and practical modalities of hyperbaric
oxygen therapy (HBO) remain controversial. This study aimed at comparing one session of HBO
at 2 absolute atmosphere followed by 4 hours of normobaric oxygen therapy to 6 hours of
normobaric oxygen therapy in adult victims of acute domestic carbon monoxide poisoning and
without coma.
Clinical Trial – Outcome Following Carbon Monoxide Poisoning in Children
Carbon monoxide poisoning is common. Many adults with CO poisoning have long-term, even
permanent brain injury following poisoning. However, very little is known about the long-term
outcome of children with carbon monoxide (CO) poisoning. In this study we plan to perform
cognitive (thinking) and vestibular (balance) testing in children (ages 6 to 16)at 6 weeks
and 6 months following CO poisoning.
At the 6-week visit, if the child and parents agree, we will ask each child to provide a DNA
sample by one of three methods: mouthwash, spit collection, or swabbing the inside of the
child’s cheek. Each child’s DNA will be analyzed for genes that are known to affect outcome
following brain injury.
Clinical Trial – Carbon Monoxide Monitoring and Emergency Treatment
Carbon monoxide (CO) has been called a "silent killer", and those patients who survive CO
poisoning are at risk of neurological damage, which may be permanent. CO is a leading cause
of unintentional poisoning deaths in the United States, and the odorless gas results in an
estimated average of 20,636 emergency department (ED) visits each year. Oxygen is the
antidote for CO poisoning, and it acts both by attenuating toxic effects and enhancing
elimination. A fractional inspired concentration of oxygen (FiO2) of 0.7 to 0.9 may be
achieved by administration of 100% oxygen delivered using a reservoir with a facemask that
prevents rebreathing. Hyperbaric oxygen therapy may provide added benefit for patients with
CO poisoning, but this therapy is unavailable in many parts of the United States including
Vermont. Use of a continuous positive airway pressure (CPAP) mask may achieve an FiO2 of 1.0,
but the effects of delivering an FiO2 of 1.0 compared to 0.7 in CO poisoning are unknown.
CPAP, by comparison, is inexpensive, portable, and available in most EDs. In this study, the
investigators are testing the hypothesis that oxygen delivered by CPAP will improve both CO
washout kinetics and functional outcomes, compared to the standard therapy of oxygen
delivered by non-rebreathing facemask. Specific Aim 1 will provide toxicokinetic data to
support a potential benefit in the use of CPAP for CO poisoning, by comparing CO elimination
kinetics in response to oxygen therapy delivered by non-rebreathing facemask versus CPAP. The
20 patients expected in our first year will provide adequate power to detect a 20% fall in
half-time of CO elimination. While CPAP may increase CO washout rates, as predicted in
Specific Aim 1, demonstration of real functional benefit will be tested in Specific Aim 2.
This Aim seeks to determine functional (neuropsychological) outcomes in patients with CO
poisoning treated with oxygen therapy delivered by non-rebreathing facemask versus CPAP. Data
showing a therapeutic benefit from CPAP in CO poisoning would have clinical implications.
Compared to hyperbaric oxygen therapy, CPAP therapy can begin earlier, including the
pre-hospital setting, for patients with known exposure. With the frequent nature of CO
poisoning and the widespread availability of CPAP, a potential benefit could lead to improved
outcomes for the 20,000+ patients who present to EDs annually.
Clinical Trial – One vs. Three Hyperbaric Oxygen Treatments for Acute Carbon Monoxide Poisoning
This randomized trial will investigate important clinical outcomes of patients with acute
carbon monoxide poisoning randomized to receive either one or three hyperbaric oxygen
treatments.