A novel infrasound and audible machine-learning approach to the diagnosis of COVID-19.

Background: The coronavirus disease 2019 (COVID-19) outbreak has rapidly spread around the world, causing a global public health and economic crisis. A critical limitation in detecting COVID-19-related pneumonia is that it is often manifested as a "silent pneumonia", i.e. pulmonary auscultation that sounds "normal" using a standard stethoscope. Chest computed tomography is the gold standard for detecting COVID-19 pneumonia; however, radiation exposure, availability and cost preclude its utilisation as a screening tool for COVID-19 pneumonia. In this study we hypothesised that COVID-19 pneumonia, "silent" to the human ear using a standard stethoscope, is detectable using a full-spectrum auscultation device that contains a machine-learning analysis. Methods: Lung sound signals were acquired, using a novel full-spectrum (3-2000 Hz) stethoscope, from 164 COVID-19 pneumonia patients, 61 non-COVID-19 pneumonia patients and 141 healthy subjects. A machine-learning classifier was constructed and the data were classified into three groups: 1) normal lung sounds, 2) COVID-19 pneumonia and 3) non-COVID-19 pneumonia. Results: Standard auscultation found that 72% of the non-COVID-19 pneumonia patients had abnormal lung sounds compared with only 25% of the COVID-19 pneumonia patients. The classifier's sensitivity and specificity for the detection of COVID-19 pneumonia were 97% and 93%, respectively, when analysing the sound and infrasound data, and they were reduced to 93% and 80%, respectively, without the infrasound data (p<0.01 difference in receiver operating characteristic curves with and without infrasound). Conclusions: This study reveals that useful clinical information exists in the infrasound spectrum of COVID-19-related pneumonia and machine-learning analysis applied to the full spectrum of lung sounds is useful in its detection.

["Concentrated KCL-free" hospital: stopping the use of potassium chloride concentrated ampoules in clinical departments and units--steps in implementing a new policy for increasing safety of drug therapy].

BACKGROUND: About one third of deaths of hospitalized patients associated with adverse drug reactions are due to hyperkalemia caused by administration of solutions that contain too high a concentration of potassium. Frequently, the reasons for these phenomena are mistakes that occur when the potassium obtained from the concentrated ampoule is diluted in the solution by department nurses. In the literature it is recommended to refrain from preparing such solutions in the departments, and to use premixed solutions which contain a known concentration of the potassium. The aim of the project was to achieve this goal in all clinical departments and units except general, pediatric, and neonatal intensive care units. METHODS: The project took place during the years 2004-2006. Included were all 26 clinical departments and units in which solutions containing potassium chloride had been used, except general, pediatric, and neonatal intensive care units. The project was carried out with the full cooperation of the medical and nursing directors in each site and included the following steps: 1. Removing all ampoules of concentrated potassium chloride from the clinical sites. 2. Increasing the availability of factory prepared potassium chloride containing premixed solutions and standardizing their use. 3. Preparing potassium chloride containing solutions, that are not available premixed, only in the pharmacy. 4. Increasing the use of oral potassium chloride when possible. RESULTS: As of January 2007: 1. In 26 (100%) of the clinical departments and units involved, no ampoules of concentrated potassium chloride are present as compared to only 2 (8%) departments that were free of the concentrate at the beginning of the project. 2. In these departments, nurses do not dilute potassium chloride. 3. The number of solutions containing potassium chloride available in the hospital has decreased from 20 to 10, all premixed. 4. No problems associated with potassium were observed in patients. CONCLUSIONS: By implementing the recommendations in the literature regarding the use of potassium chloride solutions, the possible hazards of hyperkalemia associated with intravenous use were eliminated, thus taking a proactive approach to medication safety at HaEmek Medical Center.