Comparison of carboxyhemoglobin (COHB) level and imaging methods in carbon monoxide poisoning and efficiency in diagnosis

Objective: Carbon monoxide (CO) poisoning is the most common toxic gas poisoning among all presenting to the emergency department (ED). These patients can apply to ED with very different complaints and findings. Early diagnosis and treatment is very important in order to prevent morbidity that may occur due to poisoning. It was aimed to investigate the effectiveness of CO poisoning diagnosis and prognosis in patients by comparing laboratory findings and imaging findings. Material and Method: Our study is a retrospective and cross-sectional study. Demographic data, medical history, serum carboxyhemoglobin (COHb) levels, laboratory data, vital signs, imaging findings, ECG findings and neurological examinations of the patients aged 18 years and older who came to Çukurova University Medical Faculty Hospital ED with the diagnosis of carbon monoxide poisoning were evaluated. Results: Fifty-two patients were included in the study. 55.8% of the patients were male and the mean age was 47.4 years. The most common presenting complaints were headache (59.6%) and nausea/vomiting (55.8%), respectively. 28.8% of the patients had significant neuro-imaging findings. The most common pathological imaging finding was diffuse density loss in the periventricular white matter (17.3%). Although COHb levels were high in patients with imaging findings, there was no significant correlation between the COHb levels and imaging finding (p=0.116). When COHb levels exceed 22.5%, it was shown that neurological examination findings were detected with approximately 75% sensitivity and specificity (p=0.013). Serum lactate level was found to be the most effective parameter upon detection of imaging findings in the analyzes (p=0.009). If the lactate level rises above 1.68 mmol/L, imaging finding with 65% sensitivity and specificity; It was shown that if it exceeded 2.05 mmol/L, neurological signs were detected with approximately 80% sensitivity and specificity. Conclusion: Depending on many variable factors, the patient's COHb levels do not correlate with the clinical condition. In order to make a diagnosis, COHb levels must be requested from patients who are suspected of carbon monoxide poisoning, but we think that serum lactate level is one of the most valuable parameter that can be used in the follow-up of these patients. The diagnosis of CO poisoning should be considered in patients presenting to the ED with complaints of altered mental status, headache, dizziness, shortness of breath, and nausea/vomiting. Care should be taken as the clinical course may be more severe in patients with co-morbidities such as diabetes mellitus, hipertension or coronary artery disease; COHb and serum lactate levels should be examined in these patients and neuro-imaging (CT) should be applied especially in terms of neurological involvement. Key Words: Carbon Monoxide, Carboxyhemoglobin, Computed Tomography, Emergency Department, Poisoning