Objective To explore the correlation of the indoor carbon monoxide concentration and chronic diseases by monitoring the indoor carbon monoxide concentration timely.Methods Collected the data of non-traumatic patients(n=80)from July 201 1 to January 2014,and assigned them into the experiment group with carbon monoxide concentration measured and the control group without measured.All the subjects were further divided into one group with complaint of carbon monoxide poisoning and the other one without.For patients exposed to high concentration of carbon monoxide,carboxyhemoglobin was also measured and APACHEⅡ was scaled,and the relationship between them was analyzed.The confirmation and misdiagnosis rate of carbon monoxide poison-ing were calculated.For the patients with acute exacerbation of chronic diseases like chronic cardiac failure,chronic obstructive pul-monary disease,cerebral infarction induced by carbon monoxide poisoning,BNP,CAT and NIHSS were documented on admission and during follow-up with removal of carbon monoxide exposure and compared respectively.Results The relationship between blood carboxyhemoglobin,APACHEⅡ scores on admission and indoor carbon monoxide concentration was linear,and obviously positive.Between the experiment group(n=40)and the control group(n=40),there was significant difference(P <0.05)in confirma-tion rate and misdiagnosis rate with 80.00% vs.55.00% and 6.25% vs.81.80% respectively.For the 54 patients with carbon monoxide poisoning diagnosed,the changes between before and after removal of carbon monoxide exposure of the CAT scores of chronic obstructive pulmonary disease and NIHSS score of CI disease and myoglobin,troponin I,creatine kinase isoenzyme,BNP for chronic cardiac failure were significantly different(P <0.01).Conclusion The indoor carbon monoxide concentration may indicate the severity of carbon monoxide poi-soning,which could increase the confirmation rate of carbon monoxide poisoning,and reduce the misdiagnosis rate.It is helpful to identify carbon monoxide exposure,the common inducing factor,so as to improve the patients′clinical symptoms.