Simple infrared thermometry in fever detection: consideration in mass fever screening.

OBJECTIVE: The need to rapidly screen patients during outbreaks has prompted Cutaneous Infrared Thermometry (CIT) use. Little is known of CIT performance in this context. What are the performance characteristics of simple CIT in detecting fever? DESIGN: Prospective cohort, sequential convenience sample. PARTICIPANTS: All patients presenting to the study Emergency Department for care. INTERVENTION: CIT and oral temperature measurements. MAIN OUTCOMES: Fever defined as oral temperature≥38°C. CIT is measured simultaneously with oral temperatures. Comparisons of temperatures are expressed as means and 95% confidence intervals. Means are compared using Student's t test. Limits of agreement are measured using Bland-Altman. Receiver operating characteristics are determined. RESULTS: There are 548 cases comprising 224 males, 324 females, with mean age 26 years. The mean temperature difference is 12.95°C, (13.18-9.08°C) p≤0.0001. Bland-Altman demonstrates bias at 8.680 (-9.084 to -8.275) p≤0.0001 with upper and lower level bias values of 18.124 (18.819-17.435) and 0.768 (0.076-1.459), respectively. Based on Receiver Operator Characteristics analysis, detection of hyperpyrexia at a CIT of 35.3°C provided sensitivity of 0.236 (0.143-0.359), specificity 0.977 (0.959-0.989), positive predictive value 0.589 (0.325-0.810), negative predictive value 0.904 (0.891-0.919), and accuracy of 0.888 (0.861-0.913). CONCLUSIONS: The use of a readily available CIT measurement device predicted hyperpyrexia about 59 percent of the time and the absence of hyperpyrexia about 90 percent of the time. This is consistent with previous reports of more complex infrared measurement devices. Although commonly used in mass fever screening, the current performance characteristics of CIT are limited and may add little to detection of target diseases in a mass screening context.

Nuclear terrorism.

Recent events have heightened awareness of the potential for terrorist attacks employing nonconventional weaponry such as biological agents and radiation. Historically, the philosophy of nuclear risk has focused on global or strategic nuclear exchanges and the resulting damage from large-scale releases. Currently, nuclear accidents or terrorist attacks involving low-level or regional release of radiation are considered the most likely events. Thus far, there have been several regional radiation incidents exposing hundreds of thousands of people to radiation, but there have been only a limited number of significant contaminations resulting in death. There are several different types of radioactive particles that differ in mass, extent of radiation emitted, and the degree to which tissue penetration occurs. Radiation affects its toxicity on biological systems by ionization, which creates tissue damage by the generation of free radicals, disruption of chemical bonds, and directly damaging cellular DNA and enzymes. The extent of damage depends on the type of radioisotope and the radiation dose. Radiation doses exceeding 2 to 10 Gy are considered lethal. Optimal management of radiation casualties requires knowledge of the type and dose of radiation received, a recognition of the manifestations of radiation sickness, and the use of standard medical care, decontamination, and decorporation techniques.