Diagnostic performance of the Elecsys SARS-CoV-2 antigen assay in the clinical routine of a tertiary care hospital: Preliminary results from a single-center evaluation.

BACKGROUND: This report describes a manufacturer-independent evaluation of the diagnostic accuracy of the Elecsys SARS-CoV-2 antigen assay from Roche Diagnostics in a tertiary care setting. METHODS: In this single-center study, we used nasopharyngeal swabs from 403 cases from the emergency department and intensive care unit of our hospital. The reference standard for detecting SARS-CoV-2 was the reverse-transcription polymerase chain reaction (RT-PCR) assay. Cycle threshold (Ct) values were recorded for positive RT-PCR assays. The index test was the Elecsys SARS-CoV-2 antigen assay. This electrochemiluminescence immunoassay produces results as cutoff index (COI) values, with values ≥1.00 being reported as positive. RESULTS: Of the 403 cases, 47 showed positive results in RT-PCR assays. Of the 47 RT-PCR-positive cases, 12 showed positive results in the antigen assay. Of the 356 RT-PCR-negative cases, all showed negative results in the antigen assay. Thus, the antigen assay showed a sensitivity of 26% (95% CI, 14%-40%) and specificity of 100% (95% CI, 99%-100%). Analysis of the relationship between Ct values and COI values in the 47 RT-PCR-positive cases showed a correlation coefficient of -0.704 (95% CI, -0.824 to -0.522). The true-positive rate of the antigen assay for Ct values of 15-24.9, 25-29.9, 30-34.9, and 35-39.9 was 100%, 44%, 8%, and 6%, respectively. CONCLUSIONS: The Elecsys SARS-CoV-2 antigen assay has a low sensitivity for detecting SARS-CoV-2 from nasopharyngeal swabs. Hence, we decided to not use this assay in the clinical routine of our hospital.

Prolonged critical avalanche burial for nearly 23 h with severe hypothermia and severe frostbite with good recovery: a case report.

BACKGROUND: Accidental hypothermia with severe frostbite is a rare combination of injuries with a high risk for long-term sequelae. There are widely accepted recommendations for the management of avalanche victims and for frostbite treatment, but no recommendation exists for the treatment of frostbite in severe hypothermic patients, specifically for the management of hypothermic avalanche victims presenting with frostbite. CASE PRESENTATION: We present a case of a previously healthy, 53-year-old male skier who was critically buried by an avalanche at 2300 m of altitude at an ambient temperature of - 8 °C for nearly 23 h. The victim was found with the right hand out of the snow and an air connection to outside. He was somnolent with Glasgow Coma Scale 11 (Eye 4, Verbal 2, Motor 5) and spontaneously breathing, in a severely hypothermic state with an initial core temperature of 23.1 °C and signs of cold injuries in all four extremities. After rescue and active external forced air rewarming in the intensive care unit, the clinical signs of first-degree frostbite on both feet and the left hand vanished, while third- to fourth-degree frostbite injuries became apparent on all fingers of the right hand. After reaching a core body temperature of approximately 36 °C, aggressive frostbite treatment was started with peripheral arterial catheter-directed thrombolysis with alteplase, intravenous iloprost, ibuprofen, dexamethasone and regional sympathicolysis with a right-sided continuous axillary block. After ten months, the patient had no tissue loss but needed neuropathic pain treatment with pregabalin. CONCLUSION: The combination of severe accidental hypothermia and severe frostbite is rare and challenging, as drug metabolism is unpredictable in a hypothermic patient and no recommendations for combined treatment exist. There is general agreement to give hypothermia treatment the priority and to begin frostbite treatment as early as possible after full rewarming of the patient. More evidence is needed to identify the optimal dosage and time point to initiate treatment of frostbite in severely hypothermic patients. This should be taken into consideration by future treatment recommendations.

Critically buried avalanche victims can develop severe hypothermia in less than 60 min.

BACKGROUND: A major challenge in the management of avalanche victims in cardiac arrest is differentiating hypothermic from non-hypothermic cardiac arrest, as management and prognosis differ. Duration of burial with a cutoff of 60 min is currently recommended by the resuscitation guidelines as a parameter to aid in this differentiation However, the fastest cooling rate under the snow reported so far is 9.4 °C per hour, suggesting that it would take 45 min to cool below 30 °C, which is the temperature threshold below which a hypothermic cardiac arrest can occur. CASE PRESENTATION: We describe a case with a cooling rate of 14 °C per hour, assessed on site with an oesophageal temperature probe. This is by far the most rapid cooling rate after critical avalanche burial reported in the literature and further challenges the recommended 60 min threshold for triage decisions. The patient was transported under continuous mechanical CPR to an ECLS facility and rewarmed with VA-ECMO, although his HOPE score was 3% only. After three days he developed brain death and became an organ donor. CONCLUSIONS: With this case we would like to underline three important aspects: first, whenever possible, core body temperature should be used instead of burial duration to make triage decisions. Second, the HOPE score, which is not well validated for avalanche victims, had a good discriminatory ability in our case. Third, although extracorporeal rewarming was futile for the patient, he donated his organs. Thus, even if the probability of survival of a hypothermic avalanche patient is low based on the HOPE score, ECLS should not be withheld by default and the possibility of organ donation should be considered.