ABSTRACT
BackgroundThe course of the disease in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in mechanically ventilated patients is unknown. To unravel the clinical heterogeneity of the SARS-CoV-2 infection in these patients, we designed the prospective observational Maastricht Intensive Care COVID cohort; MaastrICCht. We incorporated serial measurements that harbour aetiological, diagnostic and predictive information. The study aims to investigate the heterogeneity of the natural course of critically ill patients with SARS-CoV-2 infection. Study populationMechanically ventilated patients admitted to the Intensive Care with SARS- CoV-2 infection. Main messageWe will collect clinical variables, vital parameters, laboratory variables, mechanical ventilator settings, chest electrical impedance tomography, electrocardiograms, echocardiography as well as other imaging modalities to assess heterogeneity of the natural course of SARS-CoV-2 infection in critically ill patients. The MaastrICCht cohort is, also designed to foster various other studies and registries and intends to create an open-source database for investigators. Therefore, a major part of the data collection is aligned with an existing national Intensive Care data registry and two international COVID-19 data collection initiatives. Additionally, we create a flexible design, so that additional measures can be added during the ongoing study based on new knowledge obtained from the rapidly growing body of evidence. ConclusionThe spread of the COVID-19 pandemic requires the swift implementation of observational research to unravel heterogeneity of the natural course of the disease of SARS- CoV-2 infection in mechanically ventilated patients. Our design is expected to enhance aetiological, diagnostic and prognostic understanding of the disease. This paper describes the design of the MaastrICCht cohort. Strengths and limitations of this studyO_LISerial measurements that characterize the disease course of SARS-CoV-2 infection in mechanically ventilated patients C_LIO_LIData collection and analysis according to a predefined protocol C_LIO_LIFlexible, evolving design enabling the study of multiple aspects of SARS-CoV-2 infection in mechanically ventilated patients C_LIO_LISingle centre, including only ICU patients C_LI
ABSTRACT
IntroductionEarly differentiation between emergency department (ED) patients with and without corona virus disease (COVID-19) is very important. Chest CT scan may be helpful in early diagnosing of COVID-19. We investigated the diagnostic accuracy of CT using RT-PCR for SARS-CoV-2 as reference standard and investigated reasons for discordant results between the two tests. MethodsIn this prospective single centre study in the Netherlands, all adult symptomatic ED patients had both a CT scan and a PCR upon arrival at the ED. CT results were compared with PCR test(s). Diagnostic accuracy was calculated. Discordant results were investigated using discharge diagnoses. ResultsBetween March 13th and March 24th 2020, 193 symptomatic ED patients were included. In total, 43.0% of patients had a positive PCR and 56.5% a positive CT, resulting in a sensitivity of 89.2%, specificity 68.2%, likelihoodratio (LR) + 2.81 and LR-0.16. Sensitivity was higher in patients with high risk pneumonia (CURB-65 score [≥]3; n=17, 100%) and with sepsis (SOFA score [≥]2; n=137, 95.5%). Of the 35 patients (31.8%) with a suspicious CT and a negative PCR, 9 had another respiratory viral pathogen, and in 7 patients, COVID-19 was considered likely. One of nine patients with a non-suspicious CT and a positive PCR had developed symptoms within 48 hours before scanning. DiscussionThe accuracy of chest CT in symptomatic ED patients is high, but used as a single diagnostic test, CT can not safely diagnose or exclude COVID-19. However, CT can be used as a quick first screening tool. O_TEXTBOXKey messages What is the key question? O_LIWe investigated the diagnostic accuracy of the chest CT scan using the PCR test for diagnosing COVID-19 as reference. C_LI What is the bottom line? O_LISensitivity of chest CT is high, especially in severely ill patients, but with moderate specificity, which could in part be explained by other respiratory viruses and false negative PCR tests. C_LI Why read on? Early differentation between patients with and without COVID-19 is extremely important, and CT scan should be considered a quick screening test, and may help to overcome suboptimal sensitivity of PCR tests. C_TEXTBOX
ABSTRACT
OBJECTIVE: To evaluate the radiation dose for pregnant women and fetuses undergoing commonly used computed tomography of the pulmonary arteries (CTPA) scan protocols and subsequently evaluate the simulated effect of an optimized scan length. MATERIALS AND METHODS: A total of 120 CTPA datasets were acquired using four distinctive scan protocols, with 30 patients per protocol. These datasets were mapped to Cristy phantoms in order to simulate pregnancy and to assess the effect of an effective radiation dose (in mSv) in the first, second, or third trimester of pregnancy, including a simulation of fetal dose in second and third trimesters. The investigated scan protocols involved a 64-slice helical scan at 120 kVp, a high-pitch dual source acquisition at 100 kVp, a dual-energy acquisition at 80/140 kVp, and an automated-kV-selection, high pitch helical scan at a reference kV of 100 kVref. The effective dose for women and fetuses was simulated before and after scan length adaptation. The original images were interpreted before and after scan length adaptations to evaluate potentially missed diagnoses. RESULTS: Large inter-scanner and inter-protocol variations were found; application of the latest technology decreased the dose for non-pregnant women by 69% (7.0–2.2 mSv). Individual scan length optimization proved safe and effective, decreasing the fetal dose by 76–83%. Nineteen (16%) cases of pulmonary embolism were diagnosed and, after scan length optimization, none were missed. CONCLUSION: Careful CTPA scan protocol selection and additional optimization of scan length may result in significant radiation dose reduction for a pregnant patient and her fetus, whilst maintaining diagnostic confidence.
