Guideline sources The following summarized guidelines for the evaluation and management of carbon monoxide poisoning are prepared by our editorial team based on guidelines from the Association of the Scientific Medical Societies in Germany (AWMF 2021), the American Heart Association (AHA 2020), the American College of Emergency Physicians (ACEP 2017), and the British Thoracic Society (BTS 2017). 1 2 3 4 Guidelines 1. Screening and diagnosis Diagnosis: diagnose CO poisoning based on clinical symptoms and proven or probable exposure to CO. B Show 2 more https://web.pathway.md/diseases/recJJi8FM08RuYYAa 1/6 6/29/23, 3:25 AM Carbon monoxide poisoning Pathway Differential diagnosis: suspect differential diagnoses corresponding to the symptoms of patients with suspected CO poisoning. B Show 3 more 2. Classification and risk stratification Settings of exposure: Recognize that CO can occur in numerous situations and ambient conditions, including: fire smoke loss of consciousness without apparent cause in enclosed spaces with fireplaces (such as heaters, stoves, fireplaces, barbecues) attempted suicide - often with corresponding indicators (suicide note, taped-off rooms) in silos with large quantities of wood pellets engine exhaust (without catalytic converter) hookah use. B Classification: recognize that it is usually not possible to distinguish between acute and chronic forms in the diagnosis and treatment of CO poisoning. B 3. Diagnostic investigations History and physical examination: Determine the source of CO exposure, especially in patients with CO poisoning not being brought in by emergency medical services, in order to identify other poisoned persons and, if necessary, prevent further CO poisoning from as yet unknown sources. B Perform a neurological examination, including the mini-mental state examination, in patients with clinical symptoms. B Obtain further specific evaluation if there is sufficient suspicion of a relevant differential diagnosis. B CO pulse oximetry: As per AWMF 2021 guidelines, consider obtaining CO pulse oximetry in the prehospital setting to support a suspected diagnosis. Do not use a negative reading, especially in symptomatic patients, to exclude CO poisoning. C As per ACEP 2017 guidelines, do not use noninvasive COHb measurement (CO pulse oximetry) for the diagnosis of CO poisoning in patients with suspected acute CO poisoning. D Blood gas analysis: Obtain blood gas analysis for COHb measurement via venous, arterial, or capillary blood sampling to support diagnosis in the prehospital setting. B Obtain blood gas analysis to detect elevated COHb levels and determine pH and lactate in all patients with suspected CO poisoning. B Evaluation for cardiac injury: https://web.pathway.md/diseases/recJJi8FM08RuYYAa 2/6 6/29/23, 3:25 AM Carbon monoxide poisoning Pathway As per AWMF 2021 guidelines, obtain CK, CK-MB, troponin, as well as a 12-lead ECG for the evaluation of cardiac injury in all patients with suspected CO poisoning, especially in the presence of cardiac symptoms and history. Obtain further organ-specific evaluation if there is sufficient suspicion of relevant differential diagnoses. B As per ACEP 2017 guidelines, obtain an ECG and cardiac biomarker levels to identify acute myocardial injury, which can predict poor outcomes, in patients with moderate-to-severe CO poisoning in emergency department settings. B Toxicological screening: obtain toxicological screening (including blood ethanol level, drug screening in blood or urine) if there is evidence of concomitant poisoning or suicidal CO poisoning. B 4. Respiratory support Supplemental oxygen and ventilation: As per AWMF 2021 guidelines: Initiate immediate administration of 100% oxygen or ventilation in patients with suspected CO poisoning. Initiate oxygen administration in the prehospital phase of care. B Administer oxygen immediately at the highest possible concentration with any of the following techniques, regardless of the oxygen saturation: mask CPAP demand valve constant dosing (high-flow) via tight-fitting mask with reservoir bag invasively using appropriate airway protection if protective reflexes are inadequate. B As per BTS 2017 guidelines, aim at an oxygen saturation of 100% and use a reservoir mask at 15 L/min irrespective of the oximetry reading and PaO because an apparently 'normal' oximetry reading may be produced by COHb. B Hyperbaric oxygen therapy: As per AWMF 2021 guidelines, administer hyperbaric oxygen therapy in adult patients with signs of severe CO poisoning (including continued impaired consciousness, metabolic acidosis, respiratory failure, and/or cardiac ischemia), as well as during pregnancy. B Show 2 more As per AHA 2020 guidelines, consider administering hyperbaric oxygen therapy for the treatment of acute CO poisoning in patients with severe toxicity. C As per ACEP 2017 guidelines, administer hyperbaric oxygen therapy or high-flow normobaric therapy in patients with acute CO poisoning. B 5. Medical management https://web.pathway.md/diseases/recJJi8FM08RuYYAa 3/6 6/29/23, 3:25 AM Carbon monoxide poisoning Pathway Prehospital care: instruct first responders by the emergency dispatch center to observe measures of self-protection if signs of a potential hazard involving CO are detected and relay the information to the emergency medical services team. B Show 4 more Indications for hospital admission: admit symptomatic patients with acute CO exposure to the hospital. B Show 3 more 6. Inpatient care Serial clinical assessment: Obtain clinical monitoring in accordance with the disease severity as long as patients are symptomatic. B Recognize that clinical symptoms do not correlate with COHb clearance from the blood. Do not obtain COHb monitoring alone for treatment management. B 7. Patient education Pre-discharge counseling: educate all patients with CO poisoning about the risk of delayed neurologic sequelae, symptoms, and time of onset. Instruct patients to present to a neurologist if delayed neurologic sequelae are suspected. B 8. Preventative measures CO detectors: Ensure the use of early-warning detectors (smoke and CO alarms) in every household. B Use a multi-stage approach depending on the concentration indicated when CO warning devices are used by emergency services. B Alerting fire department: Alert the fire department to check the scene of the accident in terms of hazard prevention and undertake the necessary safety measures. B Ensure the use of respiratory protection by fire department responders if CO is detected or suspected in the ambient environment. B 9. Follow-up and surveillance Indications for neurologist referral: refer patients with suspected delayed neurologic sequelae to a neurologist. B https://web.pathway.md/diseases/recJJi8FM08RuYYAa 4/6 6/29/23, 3:25 AM Carbon monoxide poisoning Pathway Indications for discharge: consider discharging patients home from the emergency department (or leaving on site as affected individuals in the prehospital setting) after a thorough clinical examination reveals no symptoms, as well as instrument-based diagnostics, considering the individual risk constellation, and evaluation of relevant possible differential diagnoses. C Cardiac surveillance: consider obtaining interval cardiac follow-up for signs of cardiac injury in patients after acute CO poisoning in order to detect long-term cardiac damage. C Clinical findings Symptoms Past medical history Abdominal pain AKI Agitation AUD Anxiety Burns Chest pain Depression Confusion Substance use disorder Cough Vital signs Diarrhea Dizziness Hypertension Emotional lability Hypotension Fainting Tachycardia Fatigue Ocular exam Fecal incontinence Fever Corneal abrasion Hallucinations Papilledema Headache Retinal hemorrhage Memory impairment Myalgia Lab findings Nausea ALF Palpitations Hyperglycemia Paresthesia Hypokalemia Poor judgement Lactic acidosis Red eyes Metabolic acidosis Seizure blood COHb Shortness of breath serum CK Sleeping disorder serum CK-MB Trouble concentrating serum lactate Urinary incontinence serum troponin I Vertigo urine myoglobin Visual disturbances Vomiting Imaging findings Social history Pulmonary edema https://web.pathway.md/diseases/recJJi8FM08RuYYAa 5/6 6/29/23, 3:25 AM Carbon monoxide poisoning Pathway Attempted suicide Neurological exam Agnosia Altered mental status Apraxia Ataxia Coma Homonymous hemianopsia Neuropathy Parkinsonism Integument exam Cherry-red discolouration Pallor Skin erythema ECG findings Ventricular arrhythmia References 1. Bj rn J ttner, Hans-J rg Busch, Andreas Callies et al. S2k guideline diagnosis and treatment of carbon monoxide poisoning. Ger Med Sci. 2021 Nov 4;19 Doc13. Open 2. American College of Emergency Physicians Clinical Policies Subcommittee Writing Committee) on Carbon Monoxide Poisoning:, Stephen J Wolf, Gerald E Maloney et al. Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Acute Carbon Monoxide Poisoning. Ann Emerg Med. 2017 Jan;69 1 98 107.e6. Open 3. Ashish R Panchal, Jason A Bartos, Jos G Caba as et al. Part 3 Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020 Oct 20;142 16_suppl_2 S366 S468. Open 4. O'Driscoll BR, Howard LS, Earis J et al. BTS guideline for oxygen use in adults in healthcare and emergency settings. Thorax. 2017 Jun;72 Suppl 1):ii1-ii90. 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