Patients who had COHb measurements above these levels were asked to complete a second questionnaire where the patient was unable, the accompanying friend, family or staff completed this. However, because symptoms have been reported with COHb levels as low as 2.5% 32 and the investigators were anxious not to miss any possible cases, the COED group decided that a more appropriate definition of a raised COHb level in this study was ≥2.5% in non-smokers and ≥5% in smokers. Most previous studies have used a COHb level of 10% as positive. All sample times were recorded and a note was made of whether supplemental oxygen was administered between the different samples. Blood was taken if the clinical condition required this or if the pulse CO-oximeter reading was raised, as all of the departments used point-of-care blood analysers which routinely measured COHb-blood COHb levels were not measured purely for research purposes. 31 A brief questionnaire was completed by a triage nurse or researcher, which included information needed to interpret COHb levels, such as time the patient left home/work, time of arrival at the ED, whether supplemental oxygen was given en route to the ED and the patient's smoking status. Previous studies have shown that this monitor has an accuracy of ☒% below 15% 30 and 40%. Patients who were recruited to the study had their COHb level measured as soon as possible after first arrival at the department, using the Masimo RAD-57 pulse CO-oximeter (Masimo Corporation, Irvine, California, USA). Ethics approval was granted from Barking and Havering Research and Ethics Committee. The secondary objective was to identify risk factors for exposure to CO in the study population. One ED is located in a semirural setting while the others serve urban populations, two of which are in a geographical area considered to have a high incidence of CO exposure. The main objective of this study was to determine the proportion of raised carboxyhaemoglobin (COHb) levels in a targeted population of patients presenting to four EDs in England. 21–28 The Department of Health has recently estimated that 4000 people/year are diagnosed with CO poisoning by emergency departments (EDs) in England and Wales 29 but this figure does not include those whose diagnosis is missed. Studies have been conducted in the USA and Malta, which suggest that the level of CO poisoning is low in an undifferentiated healthcare population 17–20 but much higher in targeted groups (those showing clinical features that may be caused by CO, such as non-traumatic headache, cardiac chest pain, exacerbation of chronic lung disease, flu-like symptoms and seizures). However, the base of the pyramid includes chronic, low-dose exposure, which may produce symptoms that are misdiagnosed by clinicians. 13–16 CO exposure has been described as a pyramid of disease, 1 the tip of which is overtly poisoning which is more likely to be recognised by clinicians. 2–6 Evidence suggests that CO toxicity is frequently missed by healthcare professionals 7–12 and those who continue to be exposed to CO are likely to experience chronic neurocognitive dysfunction. 1 In addition, it may precipitate some chronic cardiorespiratory conditions. Both acute and chronic carbon monoxide (CO) exposure can produce a wide variety of non-specific clinical features, all of which mimic other pathologies.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |