Incidence and risk factors for carbon monoxide poisoning in an emergency department in Nepal

Abstract Incidence of carbon monoxide (CO) poisoning in Nepal has not been studied. The objective of this study was to evaluate baseline carboxyhemoglobin (COHb) concentrations, population risk factors, and incidence of CO poisoning at a single hospital in Nepal. This was a prospective, observational study of patients presenting to Patan Hospital Emergency Department from April 2019 to March 2020. Demographics, risk factors for CO poisoning, symptoms, and clinical pretest probability of CO poisoning was documented. COHb concentration was obtained using a noninvasive co-oximeter. Significant CO exposure was defined as COHb concentration > 10%. CO poisoning was defined as COHb > 10% coupled with symptoms. Of 1,040 patients, 745 patients had a recordable COHb concentration. Median age was 40 years (IQR 33) with 407 (55%) females. Average COHb was 7.2%. Warm months were associated with higher COHb concentrations (8.1% vs 6.0%, p < 0.05). Firewood use had higher COHb concentrations compared to gas heating (8.6% vs 7.0%, p < 0.05). Overall, 228 (31%) patients had a COHb concentration > 10% indicating significant CO exposure. Sixteen patients had CO poisoning. We found a significant baseline incidence of COHb > 10% (31%) in patients presenting to a hospital in Nepal. Risk factors for higher baseline COHb concentrations included warm months and cooking with firewood.