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Chapter 24 Coordinating Care for Patients With Infectious Respiratory Disorders
if no fever (without the use of antipyretic medications) for 24 hours and symptoms are improving or resolved. Nonhospitalized individuals with moderate illness should quarantine for a full 10 days and follow practices for con- tainment and spread reduction. Hospitalized patients with moderate to severe COVID-19 illness are isolated for at least 10 days and up to 20 days after symptoms began or from the date of a positive COVID-19 test. Isolation may be discontinued after the 10-to-20–day period if no fever (without the use of antipyretic medications) and respira- tory symptoms have resolved. Diagnosis The gold standard for COVID-19 diagnosis is the reverse transcriptase polymerase chain reaction test (RT-PCR) that recognizes different regions of the SARS-CoV-2 RNA. Samples are obtained by nasopharyngeal swabs with results in 3 to 5 days (outpatient testing) or a few hours (inpa- tient testing) (Fig. 24.3). Studies performed by the Amer- ican Society for Microbiology demonstrate saliva testing as showing promise in providing faster and reliable detec- tion of the virus. In-home rapid antigen test (RAT) kits are available in the United States and are used primarily for school- and employer-mandated testing. False-negative resulting has been found among different testing supplies and in the presence of low viral loads; therefore, a single negative test should not be considered definitive for the absence of infection. The CDC recommends at-home testing to consist of two tests performed 24 to 36 hours apart for increased confidence in results. Additional diagnostic testing including chest imaging (chest radiography, ultrasound, and computed tomog- raphy) are useful adjuvant studies in the confirmation of COVID-19 pneumonia and should be carefully interpreted in the absence of a positive virology test. Serum laboratory testing should consist of the following: l Complete blood count l Chemistries l ABGs (as indicated to detect hypercarbia or acidosis) l Lactate
l Coagulation screen (including D-dimer) l Inflammatory markers (serum procalcitonin and C-reactive protein) l Ferritin
l Lactate dehydrogenase (LDH) l Creatine kinase (CK), CK-MB l Troponin l Blood and sputum cultures
Evidence-Based Practice Pulse Oximetry Bias in Patients of Racial and Ethnic Minority Groups Oxygen saturation monitoring using pulse oximetry in patients with respiratory illness is a frequently used tool for triaging, monitoring progress or deterioration, and titration of oxygen delivery. This technology utilizes a light source that shines through the skin at two wave- lengths. Analyzing the light absorbance allows for esti- mating the percentage of oxygen in red blood cells. In two large cohort studies during the COVID-19 pan- demic, patients of color were found to have three times the frequency of occult hypoxemia not detected by pulse oximetry but demonstrated on arterial blood gas sampling. Managing patients with unreliable pulse oximetry measurements is hazardous for several reasons: (1) dan- gerously low oxygen saturations are missed; (2) exag- gerated low or high saturations lead to the delivery of inappropriate concentrations of oxygen; and (3) identi- fying patients who become eligible for treatments based on saturation values may be delayed or omitted. Indications for Practice Ensure proper placement of the pulse oximetry probe with considerations for the patient’s skin tone, temper- ature, and perfusion status. Utilize appropriate alternate site placement for improved accuracy: l Earlobe l Forehead l Nasal bridge Collect ABG samples in the setting of worsening respi- ratory parameters (increased respiratory rate, work of breathing, anxiety/restlessness, and oxygen require- ments) regardless of pulse oximetry readings. Tobin, M. J., & Jubran, A. (2022). Pulse oximetry, racial bias and statistical bias. Annals of Intensive Care, 12 (1), 2. https://doi.org/10.1186/s13613- 021-00974-7 Valbuena, V. S., Merchant, R. M., & Hough, C. L. (2022). Racial and ethnic bias in pulse oximetry and clinical outcomes. JAMA Internal Medicine, 182 (7), 699–700. doi:10.1001/jamainternmed.2022.1903
FIGURE 24.3 Obtaining a nasopharyngeal swab for COVID-19 testing.
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