Risk Factors and Computed Tomography Findings in COVID-19.
Risk Factors and Computed Tomography Findings in COVID-19.
In the SARS-CoV2 pandemic, imaging studies proved its diagnostic utility to determine the
 severity of lung involvement. Computed tomography (CT) is a state-of-the-art study proven to
 be a highly sensitive diagnostic test complemented by RT-PCR testing to determine the disease
 and the degree of severity.

 In March 2020, the Dutch Society of Radiology developed a standardized assessment scheme for
 COVID-19 lung disease, called CO-RADS. This system proposes a level of suspicion of pulmonary
 involvement of COVID-19, based on the simple chest tomography findings. The level of
 suspicion ranges from very low (CO-RADS 1) to very high (CO-RADS 5), with two additional
 categories involving a technically deficient study (CO-RADS 0) and a positive RT-PCR test for
 SARS -CoV-2 known before tomography (CO-RADS 6).

 For its part, acute respiratory damage secondary to SARS-COV2 pneumonia causes acute
 respiratory distress syndrome, which warrants immediate medical attention. During the
 evaluation and triage of patients with suspected or confirmed SARS-COV2 infection, it is a
 challenge for health personnel given that the severity and clinical presentation is highly
 variable. The patient's risk stratification is carried out using previously established and
 validated risk scales and is a fundamental tool for making clinical decisions. Some of the
 risk indices and scales have been developed and used in the pandemic epicenters, such as
 China and Europe. Useful for the clinician is the national early warning scale (NEWS 2),
 severe disease risk assessment score (COVID-GRAM), the rapid severity index for COVID-19
 (qCSI), evaluation score of Modified sequential organ failure (mSOFA), the sepsis-induced
 coagulopathy score (SIC), the ROX index as a predictor of success to the high-flow nasal
 cannula. The evaluation of the risk of thrombotic complications such as the Padua risk, of
 cardiac complications such as QT segment prolongation, through the Tisdale risk score.

 Risk stratification is essential in the current COVID-19 pandemic situation; upon admission,
 the clinician will discern if the patient requires in-hospital medical treatment, the risk of
 severe disease, and progression to assisted mechanical ventilation.

 This work aims to establish whether the severity of the findings identified by cardiac
 tomography upon admission and the risk established by the different established prognostic
 indices.
Introduction

 In the SARS-CoV2 pandemic, imaging studies proved its diagnostic utility to determine the
 severity of lung involvement. Computed tomography (CT) is a state-of-the-art study proven to
 be a highly sensitive diagnostic test complemented by RT-PCR testing to determine the disease
 and the degree of severity.

 In March 2020, the Dutch Society of Radiology developed a standardized assessment scheme for
 COVID-19 lung disease, called CO-RADS. This system proposes a level of suspicion of pulmonary
 involvement of COVID-19, based on the simple chest tomography findings. The level of
 suspicion ranges from very low (CO-RADS 1) to very high (CO-RADS 5), with two additional
 categories involving a technically deficient study (CO-RADS 0) and a positive RT-PCR test for
 SARS -CoV-2 known before tomography (CO-RADS 6).

 Acute respiratory damage secondary to SARS-COV2 pneumonia causes acute respiratory distress
 syndrome, which must meet the Berlin criteria. The evaluation and triage of patients with
 suspected or confirmed SARS-COV2 infection is a challenge for emerging healthcare systems.
 The risk stratification of the patient is carried out with previously established and
 validated risk scales.

 However, scales such as the national early warning scale (NEWS 2) are an option for health
 personnel, NEWS 2 determines the degree of illness of a patient and promotes intensive care
 intervention. It includes assessing oxygen saturation, hypercapnic respiratory failure
 (usually chronic obstructive pulmonary disease), confusion, disorientation, delirium, or any
 reduction in the Glasgow coma scale as potential findings of clinical deterioration. With a
 score of 0-4, it grants a low risk. It recommends the evaluation carried out by a competent
 registered nurse or equivalent to decide the change in the frequency of clinical follow-up or
 the intensification of care, on the contrary with a score of more than 7, grants high risk
 and recommends Emergency Assessment by a clinical or intensive care team and is usually
 transferred to a higher level of care.

 Predicting the development of severe pneumonia and the need for ventilatory support is vital
 for the clinician, as is the scale of COVID-GRAM; which assesses abnormalities in
 radiography, age of the patient, hemoptysis, dyspnea, state of consciousness, number of
 comorbidities, neutrophil/lymphocyte index, lactic dehydrogenase and direct bilirubin. It
 establishes three risk groups: the mild one with a risk of critical illness of less than 1.7%
 and the high risk of more than 40.4%.

 The even more simplified rapid severity index for COVID-19 (qCSI) predicts the risk of acute
 respiratory disease in 24 hours in patients admitted from the emergency department. Only the
 heart rate, oxygen saturation, and oxygen flow to the patient are quantified. A score less
 than or equal to 3 gives a low risk with a critical illness risk of 4%, while a score of
 10-12 gives a high risk and a critical illness probability of 57%.

 Regarding sepsis evaluation, the mSOFA scale implemented in 2010 and validated in 2019 can
 predict in-hospital mortality and 30 days, with a minimum score of 0-7 that translates
 mortality of 0% and a score greater than 11 translates mortality of 58%. The risk of
 coagulopathy induced by sepsis secondary to COVID-19 will be present, and the sepsis-induced
 coagulopathy score scale (SIC) refers to the diagnosis of coagulopathy when the score is more
 significant than four, or the INR is greater than or equal to 3.

 On the other hand, oxygen therapy is a cornerstone in the treatment of respiratory distress
 secondary to SARS-COV2 pneumonia; therapy with high flow nasal cannula (CNAF) in the
 treatment of acute respiratory failure (ARF), the ROX index (IROX) has been proposed as a
 predictor of the success of CNAF at 2, 6 and 12 h of a treatment since it is essential to
 have tools that allow us to detect failure early of the technique since a delay in intubation
 can lead to increased mortality. A ROX index less than 3.85 predicts a high risk of the need
 for intubation, and a value of 4.88 predicts a low risk of intubation.

 In the present pandemic, numerous reports of the coexistence of a hyper coagulant state
 secondary to COVID-19 infection have become evident, so evaluating the thrombotic risk and
 initiation of anticoagulation is essential and accepted in the standard treatment in patients
 with SARS infection -COV2. The Padua Risk is used; it is a simple risk assessment (MSER) that
 can help clinicians discriminate between the high and low risk of venous thrombus embolism
 (VTE). A score greater than or equal to four was not associated with VTE during or after
 hospitalization; however, a Padua score of ≥4 was associated with higher mortality.

 Regarding the therapeutics to be used, all drugs' adverse effect is known, which is why it is
 necessary to scrutinize some used in SARS-CoV2 infection, such as the use of certain
 antimalarials, antibiotics, and antivirals-leading to alterations in heart rhythm, the
 Tisdale risk score for the risk of QT segment prolongation more significant than 500 ms
 during hospitalization. A Tisdale score less than 6 translates to a low risk of QT
 prolongation, while a score of more than 11 translates to high risk, and it is recommended to
 consult with the pharmacist, adjust the risk factors as much as possible and use alternative
 medications if possible.

 Risk stratification is essential in the current COVID-19 pandemic situation; upon admission,
 the clinician will discern if the patient requires in-hospital medical treatment, the risk of
 severe disease, and progression to assisted mechanical ventilation. This work aims to
 establish whether the severity of the findings identified by cardiac tomography upon
 admission and the risk established by the different established prognostic indices.

 Problem Statement

 The severity of the disease is influenced by comorbidities resulting from complications or
 death in any disease. In SARS-CoV2, it is known that conditions such as diabetes mellitus,
 obesity, systemic arterial hypertension, neoplastic or autoimmune disease can increase the
 risks of fatal outcomes. However, timely decisions to offer optimal therapy are a priority in
 the present global health situation.

 In this COVID-19 pandemic, the risk indices and scales are of vital importance in the correct
 risk stratification of the patient with SARS-CoV2 infection, which leads to a better medical
 approach decision, which therefore leads to better outcomes.

 Research Question

 Will the prognostic indices and the specific staging allow us to identify with greater
 certainty a clinical state of severity in patients infected with SARS-CoV2?

 Justification

 Despite the significant advances in basic and clinical research during this year, severe
 SARS-CoV2 pneumonia and sepsis with multiple organ failure have been the leading cause of
 morbidity and mortality in intensive care units worldwide. The analysis of the
 pathophysiological mechanisms responsible for this pandemic has allowed us to recognize some
 critical points for its control and therapeutic management; however, it is necessary to
 search for new, mainly preventive treatments where the critical measures of timely
 recognition of patients who can evolve to a deleterious condition.

 The management and therapeutic decision granted to patients admitted for COVID-19 infection
 in a hospital should be uniformly known by the health personnel who treat them. However, for
 those specific points are required, easy to obtain at any healthcare center's disposition.

 Although many indices allow follow-up to regulate medical behavior, many fatal outcomes were
 related to the non-standardization and interpretation of the clinical data that the patient
 had at the time of requesting medical attention. The use of imaging studies when suspected of
 COVID-19 was a universal decision that allowed to regulate therapeutic decisions and
 hospitalization of the patient. The ambiguity and variability of the clinical expression that
 patients infected with SARS-CoV2 presented at the time of the first evaluation in the
 emergency department are known.

 It is necessary to analyze the performance of the various indices and the data provided by
 tomography to determine if there are relevant parameters from the beginning that subsequently
 led them to be critically ill.

 This study intends to evaluate the correlation of the severity indices by computed tomography
 and the clinical risk indices. These clinical and laboratory variables are evaluated in the
 patient's first contact concerning their health status and clinical outcome.

 Goals

 Overall objective:

 • Determine the severity and prognosis of COVID-19 through computed tomography evaluation and
 the patient's various risk indices in their initial medical evaluation.

 Particular objectives:

 -  Describe the findings in lung computed tomography in COVID-19 (ground glass, pleural
 effusion, pneumothorax, areas of condensation, etc.).

 -  Calculate CO-RADS

 -  Calculate the score for pneumonia severity (CURB-65).

 -  Calculate the COVID-GRAM score.

 -  Calculate the neutrophil/lymphocyte ratio.

 -  Calculate the modified sequential organ failure assessment (mSOFA) score.

 -  Calculate the sepsis-induced coagulopathy (SIC) score

 -  Calculate the ROX ratio

 -  Calculate the rapid COVID-19 severity index (qCSI)

 -  Calculate the arterial alveolus gradient score.

 -  Calculate Tisdale score for risk of QT prolongation.

 -  Calculate the Berlin score for ARDS.

 Hypothesis

 Alternative hypothesis:

 The CO-RADS by computed tomography and the combined initial risk stratification indices
 establish severity and prognosis in patients with COVID-19 infection.

 Materials and methods

 Study design.

 It is a retrospective, observational, comparative, and cross-sectional study at the Ignacio
 Chávez National Institute of Cardiology. Patients will be evaluated in whom, through the
 initial triage, a computed tomography (CT) scan was requested due to suspected pneumonia due
 to COVID-19, between April 1 and August 28, 2020.

 Sample size calculation

 This is a study calculated to determine the severity using computed tomography and its
 correlation with the indices, with which 236 subjects have been calculated in the recruitment
 of patients with an objective sample. This method approaches the calculation of the different
 forecasts determined by correlation.

 Origin of the subjects.

 Patients admitted to the emergency department, coronary unit, or post-surgical therapy unit
 of the National Institute of Cardiology Ignacio Chávez.

 Analysis strategy

 Continuous variables will be expressed as mean with standard deviation; categorical variables
 are expressed as frequencies and percentages. The normality of the variables will be
 evaluated using the Shapiro-Wilk test. Those variables with normal distribution will be
 analyzed with parametric tests (Student's t-test). Various non-parametric tests
 (Mann-Whitney, Kruskal-Wallis test, or Wilcoxon signed-rank test depending on the particular
 case) will be used to contrast variables without Gaussian distribution. For the multivariate
 analysis, binary logistic regression analysis or a multivariate regression escalation will be
 performed depending on the findings.

 Ethical considerations

 This protocol will be sent for review by the Ethics and Research Committees of the Ignacio
 Chávez National Institute of Cardiology and will be based on the Declaration of Helsinki's
 recommendations. The anonymity of all patients will be preserved. It is an observational
 study without intervention, so that it will be initiated through the authorization of the
 Research Committee's decision.
Inclusion Criteria:

 -  Patients who go to the emergency department meet the criteria for a suspected,
 probable, or confirmed case of COVID-19 infection.

 -  Patients who have undergone a simple chest tomography during their stay in the INC
 Emergency Department.

 -  Patients whose information and data availability can be obtained through the triage's
 electronic clinical record carried out in the emergency department and coronary unit.

 -  Patients with clinical data, laboratory data, oxygen saturation, and inspired oxygen
 fraction are necessary to evaluate prognostic indices.

 -  Test for SARS-CoV2 infection by RT-PCR reported as positive, negative, or not
 performed, but with suspicion of COVID-19.

 -  Patients who have had an arterial blood gas.

 Exclusion Criteria:

 -  Patients with incomplete clinical, laboratory, blood gas parameters.

 -  Patients in whom saturation and initial FiO2 are not reported.

 -  Patients referred to another Hospital during their initial evaluation.