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Carbon Monoxide Poisoning The Silent Killer. Otto F. Sabando DO FACOEP Program Director Dept. Of Emergency Medicine St. Joseph’s Regional Medical Center Paterson NJ. Case Presentation.
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Carbon Monoxide PoisoningThe Silent Killer Otto F. Sabando DO FACOEP Program Director Dept. Of Emergency Medicine St. Joseph’s Regional Medical Center Paterson NJ
Case Presentation • A 18 y.o. male presents to the ED via ambulance for “wondering around the highway. He is acutely confused and not focusing on questions. It is winter and there was a traffic jam. • His PMH, SH, Medications, PSH and FH are unknown.
Case Presentation • What other questions can be asked from the paramedic? • Physical Exam • His vital signs are T: 99 F oral, P110, • RR: 20 BP: 120/80 SaO2: 98% RA • Physical exam: neuro: disoriented to time and place, not following commands.
What is the differential? Meningitis Toxicology DKA Head injury CVA Uremia Seizure Brain tumor Medication side effect Severe anemia Hypotension Malingerer Normal and lost in the Bronx Overdose Post-ictal state Case Presentation
Case Presentation • Plan of care • Cardiac monitor • Finger stick • OXYGEN • Restraints • Labs • CBC, CMP, ABG, U/A, Urine tox., blood c/s x2, ETOH, ASA, Tylenol • Other ancillary studies
Case Presentation • CXR • CT brain • EKG
Case Presentation • What test will yield the best information in what’s going on? • ABG • EKG
Raccoon causes carbon monoxide fatality in East Sandwich By Ira Kantor Tuesday, December 23, 2008 - Updated 37d 4h ago E-mail Printable (7) Comments Text size Share (5) Rate A 62-year-old East Sandwich man was found dead of carbon monoxide poisoning in his home Sunday morning after a raccoon crawled into his chimney flue and blocked it, police and fire officials said. “He was of such a size that it was a complete blockage of the products of combustion from the gas appliance,” said Sandwich Deputy Fire Chief Tom Corriveau. “So there was nowhere for them to go but back into the residence.” Death by Raccoon!
Background • Epidemiology • Leading cause of poisoning M&M in US • 20,000 cases reported to PCCs annually • 500-5000 deaths in US • Half are suicides • 1/3 from fires
Coal and wood Engine exhaust Propane powered vehicles Methylene chloride Paint, varnish removers Home heating Natural gas stoves Kerosene heaters Clothes dryers Fire places Sources
Pathophysiology • COHb leads to decrease oxygen content in blood, shifts the O2-Hb dissociation curve to the left. • CO bind to myoglobin leading to myocardial and skeletal muscle hypoxia
Pathophysiology • CO binds to cytochrome oxidase leads to impaired mitochondrial respiration • Lipid peroxidation in CNS leading to neurologic sequelae
Nervous system HA Dizziness Nausea Blurred vision AMS Ataxia Seizures Coma Cardiovascular system Exert ional dyspnea Weakness Angina Palpitations Hypotension MI Dysrhythmias Clinical Presentation
Respiratory system ARDS Pulmonary edema Renal system ARF secondary to ATN or rhabdomyolysis Dermal system Bullae, cherry-red color Musculoskeletal Atraumatic rhabdomyolysis Clinical Presentation
Normal: 1-2% COHb Level(%) 10-20 30 40-50 60-70 80 Smokers: 5-10% Symptoms “flu-like” symptoms Severe HA, impaired judgment Confusion, LOC, minimal level for lethality as per M.E. Cardiovascular collapse, death Rapidly fatal COHb levels
Case Presentation • CO level is 30% • What do we do now? • Send the patient to hyperbaric chamber!
Indications for Hyperbaric Oxygen • Evidence of end organ damage • LOC, Coma, seizures, visual symptoms • MI, Dysrhythmias • Persistent symptoms after tx with 1 ATM O2 • COHb levels • COHb > 25% • COHb > 15% in pregnant patient
Case Presentation • While waiting for transfer to HBO, what is the half-life of CO if the pt. has been on 100% O2 at 1 ATM? • 90 min.
Room air (21%) 100% at 1 ATM 100% at 3 ATM 2-7 hrs mean is 5 hrs 36-137min mean is 60 min. 4-86 min mean is 40 min. Half life of COHb
Mechanism of HBO • Decreases half-life of COHb • Displaces CO from myoglobin and cytochrome oxidase in tissues • Increases O2 content of blood
Evidence Base Medicine for HBO • Choi HS: Delayed neurologic sequelae in CO intoxication.Arch Neurol 1983;40:433-435 • Without HBO • 12% persistent CNS signs or symptoms • 12% delayed neurologic sequelae • 2%death
Evidence Base Medicine for HBO • Delayed Neurologic sequelae • Resolution: • Mild: 100% within 2 months • Severe: 75% within 1 year (average 3-6 months) • Elderly most susceptible
Evidence Base Medicine for HBO • Goulon M, Barios M et al: CO intoxication and treatment with hyperbaric oxygen. Journal of Hyperbaric Medicine 1986;1:23 • HBO within 6hrs mortality decreased from 30% to 13.5% • Delayed neurologic sequalae (DNS): 30% to 5.5%
Evidence Base Medicine for HBO • Scheinkestel CD, Bailey M, Myles PS et al: Hyperbaric or normobaric oxygen for acute CO poisoning: a randomized controlled clinical trial. Med J Aust 1999; 170:203-210 • Found no benefit • 100% O2 for three days by facemask then HBO treatment • Most of the patients were suicidal • Follow up was only 46%
Evidence Base Medicine for HBO • Weaver LK, Hopkins RO, Chan KJ, et al. Hyperbaric oxygen for acute CO poisoning. N Engl J Med 2002;347:1057-67 • Reduced the risk of DNS 6 weeks and 1 year after acute CO poisoning
HBO Treatment • Patient’s must receive treatment within 6 hrs.
ED Management • Remove from exposure • 100% O2 by mask • COHb levels: venous or arterial • Pulse oximetry • Assess end organ damage.
Special Cases • Family that may walk in with “flu-like” symptoms that get better during the day and worse at night. • Ask about where they live and what kind of heating system they have. • Ask if any pets are sick at home with unknown etiology.
Methylene Chloride • Easily absorbed through the skin as well as inhalation • Metabolized in the liver to CO • Half life prolonged to 13 hrs.
Prevention and Education • Yearly inspections of boiler • Check cars exhaust systems • Check ventilation ducts of fire places • Clean snow from exhaust system
Prevention and Education • CO monitors • Standard in new houses in NJ • Cost $25-$50 • Fire detectors • Mandatory in houses • Cost $15!