Barotrauma during Noninvasive Respiratory Support in COVID-19 Pneumonia Outside ICU: The Ancillary COVIMIX-2 Study.

BACKGROUND: Noninvasive respiratory support (NIRS) has been extensively used during the COVID-19 surge for patients with acute respiratory failure. However, little data are available about barotrauma during NIRS in patients treated outside the intensive care unit (ICU) setting. METHODS: COVIMIX-2 was an ancillary analysis of the previous COVIMIX study, a large multicenter observational work investigating the frequencies of barotrauma (i.e., pneumothorax and pneumomediastinum) in adult patients with COVID-19 interstitial pneumonia. Only patients treated with NIRS outside the ICU were considered. Baseline characteristics, clinical and radiological disease severity, type of ventilatory support used, blood tests and mortality were recorded. RESULTS: In all, 179 patients were included, 60 of them with barotrauma. They were older and had lower BMI than controls (p < 0.001 and p = 0.045, respectively). Cases had higher respiratory rates and lower PaO2/FiO2 (p = 0.009 and p < 0.001). The frequency of barotrauma was 0.3% [0.1-1.3%], with older age being a risk factor for barotrauma (OR 1.06, p = 0.015). Alveolar-arterial gradient (A-a) DO2 was protective against barotrauma (OR 0.92 [0.87-0.99], p = 0.026). Barotrauma required active treatment, with drainage, in only a minority of cases. The type of NIRS was not explicitly related to the development of barotrauma. Still, an escalation of respiratory support from conventional oxygen therapy, high flow nasal cannula to noninvasive respiratory mask was predictive for in-hospital death (OR 15.51, p = 0.001). CONCLUSIONS: COVIMIX-2 showed a low frequency for barotrauma, around 0.3%. The type of NIRS used seems not to increase this risk. Patients with barotrauma were older, with more severe systemic disease, and showed increased mortality.

Two-year multidisciplinary follow-up of COVID-19 patients requiring invasive and noninvasive respiratory support.

BACKGROUND: COVID-19 patients frequently develop respiratory failure requiring mechanical ventilation. Data on long-term survival of patients who had severe COVID-19 are insufficient. We assessed and compared two-year survival, CT imaging, quality of life, and functional recovery of COVID-19 ARDS patients requiring respiratory support with invasive (IMV) versus noninvasive ventilation (NIV). METHODS: Patients with COVID-19 pneumonia admitted up to May 28th, 2020, who required IMV or NIV, and survived to hospital discharge were enrolled. Patients were contacted two years after discharge to assess vital status, functional, psychological, and cognitive outcomes using validated scales. Patients with persistent respiratory symptoms or high burden of residual lung damage at previous CT scan received a two-year chest CT scan. RESULTS: Out of 61 IMV survivors, 98% were alive at two-year follow-up, and 52 completed the questionnaire. Out of 82 survivors receiving NIV only, 94% were alive at two years, and 47 completed the questionnaire. We found no major differences between invasively and noninvasively ventilated patients, with overall acceptable functional recovery. Among the 99 patients completing the questionnaire, 23 have more than moderate exertional dyspnea. Chest CT scans showed that 4 patients (all received IMV) had fibrotic-like changes. CONCLUSIONS: Patients who received mechanical ventilation due to COVID-19 and were discharged from hospital had a 96% survival rate at the two-year follow-up. There was no difference in overall recovery and quality of life between patients who did and did not require IMV, although respiratory morbidity remains high.

The Macklin effect closely correlates with pneumomediastinum in acutely ill intubated patients with COVID-19 infection.

PURPOSE: Patients with COVID-19 infection are frequently found to have pulmonary barotrauma. Recent work has identified the Macklin effect as a radiographic sign that often occurs in patients with COVID-19 and may correlate with barotrauma. METHODS: We evaluated chest CT scans in COVID-19 positive mechanically ventilated patients for the Macklin effect and any type of pulmonary barotrauma. Patient charts were reviewed to identify demographic and clinical characteristics. RESULTS: The Macklin effect on chest CT scan was identified in a total of 10/75 (13.3%) COVID-19 positive mechanically ventilated patients; 9 developed barotrauma. Patients with the Macklin effect on chest CT scan had a 90% rate of pneumomediastinum (p < 0.001) and a trend toward a higher rate of pneumothorax (60%, p = 0.09). Pneumothorax was most frequently omolateral to the site of the Macklin effect (83.3%). CONCLUSION: The Macklin effect may be a strong radiographic biomarker for pulmonary barotrauma, most strongly correlating with pneumomediastinum. Studies in ARDS patients without COVID-19 are needed to validate this sign in a broader population. If validated in a broad population, future critical care treatment algorithms may include the Macklin sign for clinical decision making and prognostication.

Clinical use of Macklin-like radiological sign (Macklin effect): A systematic review.

INTRODUCTION: Recent studies suggested that Macklin sign is a predictor of barotrauma in patients with acute respiratory distress syndrome (ARDS). We performed a systematic review to further characterize the clinical role of Macklin. METHODS: PubMed, Scopus, Cochrane Central Register and Embase were searched for studies reporting data on Macklin. Studies without data on chest CT, pediatric studies, non-human and cadaver studies, case reports and series including <5 patients were excluded. The primary objective was to assess the number of patients with Macklin sign and barotrauma. Secondary objectives were: occurrence of Macklin in different populations, clinical use of Macklin, prognostic impact of Macklin. RESULTS: Seven studies enrolling 979 patients were included. Macklin was present in 4-22% of COVID-19 patients. It was associated with barotrauma in 124/138 (89.8%) of cases. Macklin sign preceded barotrauma in 65/69 cases (94.2%) 3-8 days in advance. Four studies used Macklin as pathophysiological explanation for barotrauma, two studies as a predictor of barotrauma and one as a decision-making tool. Two studies suggested that Macklin is a strong predictor of barotrauma in ARDS patients and one study used Macklin sign to candidate high-risk ARDS patients to awake extracorporeal membrane oxygenation (ECMO). A possible correlation between Macklin and worse prognosis was suggested in two studies on COVID-19 and blunt chest trauma. CONCLUSIONS: Increasing evidence suggests that Macklin sign anticipate barotrauma in patients with ARDS and there are initial reports on use of Macklin as a decision-making tool. Further studies investigating the role of Macklin sign in ARDS are justified.

Prognosis of Spontaneous Pneumothorax/Pneumomediastinum in Coronavirus Disease 2019: The CoBiF Score.

Objectives: Pneumothorax and pneumomediastinum are associated with high mortality in invasively ventilated coronavirus disease 2019 (COVID-19) patients; however, the mortality rates among non-intubated patients remain unknown. We aimed to analyze the clinical features of COVID-19-associated pneumothorax/pneumomediastinum in non-intubated patients and identify risk factors for mortality. Methods: We searched PubMed Scopus and Embase from January 2020 to December 2021. We performed a pooled analysis of 151 patients with no invasive mechanical ventilation history from 17 case series and 87 case reports. Subsequently, we developed a novel scoring system to predict in-hospital mortality; the system was further validated in multinational cohorts from ten countries (n = 133). Results: Clinical scenarios included pneumothorax/pneumomediastinum at presentation (n = 68), pneumothorax/pneumomediastinum onset during hospitalization (n = 65), and pneumothorax/pneumomediastinum development after recent COVID-19 treatment (n = 18). Significant differences were not observed in clinical outcomes between patients with pneumomediastinum and pneumothorax (±pneumomediastinum). The overall mortality rate of pneumothorax/pneumomediastinum was 23.2%. Risk factor analysis revealed that comorbidities bilateral pneumothorax and fever at pneumothorax/pneumomediastinum presentation were predictors for mortality. In the new scoring system, i.e., the CoBiF system, the area under the curve which was used to assess the predictability of mortality was 0.887. External validation results were also promising (area under the curve: 0.709). Conclusions: The presence of comorbidity bilateral pneumothorax and fever on presentation are significantly associated with poor prognosis in COVID-19 patients with spontaneous pneumothorax/pneumomediastinum. The CoBiF score can predict mortality in clinical settings as well as simplify the identification and appropriate management of patients at high risk.

High Risk of Secondary Infections Following Thrombotic Complications in Patients With COVID-19.

Background: This study's primary aim was to evaluate the impact of thrombotic complications on the development of secondary infections. The secondary aim was to compare the etiology of secondary infections in patients with and without thrombotic complications. Methods: This was a cohort study (NCT04318366) of coronavirus disease 2019 (COVID-19) patients hospitalized at IRCCS San Raffaele Hospital between February 25 and June 30, 2020. Incidence rates (IRs) were calculated by univariable Poisson regression as the number of cases per 1000 person-days of follow-up (PDFU) with 95% confidence intervals. The cumulative incidence functions of secondary infections according to thrombotic complications were compared with Gray's method accounting for competing risk of death. A multivariable Fine-Gray model was applied to assess factors associated with risk of secondary infections. Results: Overall, 109/904 patients had 176 secondary infections (IR, 10.0; 95% CI, 8.8-11.5; per 1000-PDFU). The IRs of secondary infections among patients with or without thrombotic complications were 15.0 (95% CI, 10.7-21.0) and 9.3 (95% CI, 7.9-11.0) per 1000-PDFU, respectively (P = .017). At multivariable analysis, thrombotic complications were associated with the development of secondary infections (subdistribution hazard ratio, 1.788; 95% CI, 1.018-3.140; P = .043). The etiology of secondary infections was similar in patients with and without thrombotic complications. Conclusions: In patients with COVID-19, thrombotic complications were associated with a high risk of secondary infections.

Atlas-based lung segmentation combined with automatic densitometry characterization in COVID-19 patients: Training, validation and first application in a longitudinal study.

PURPOSE: To develop and validate an automated segmentation tool for COVID-19 lung CTs. To combine it with densitometry information in identifying Aerated, Intermediate and Consolidated Volumes in admission (CT1) and follow up CT (CT3). MATERIALS AND METHODS: An Atlas was trained on manually segmented CT1 of 250 patients and validated on 10 CT1 of the training group, 10 new CT1 and 10 CT3, by comparing DICE index between automatic (AUTO), automatic-corrected (AUTOMAN) and manual (MAN) contours. A previously developed automatic method was applied on HU lung density histograms to quantify Aerated, Intermediate and Consolidated Volumes. Volumes of subregions in validation CT1 and CT3 were quantified for each method. RESULTS: In validation CT1/CT3, manual correction of automatic contours was not necessary in 40% of cases. Mean DICE values for both lungs were 0.94 for AUTOVsMAN and 0.96 for AUTOMANVsMAN. Differences between Aerated and Intermediate Volumes quantified with AUTOVsMAN contours were always < 6%. Consolidated Volumes showed larger differences (mean: -95 ± 72 cc). If considering AUTOMANVsMAN volumes, differences got further smaller for Aerated and Intermediate, and were drastically reduced for consolidated Volumes (mean: -36 ± 25 cc). The average time for manual correction of automatic lungs contours on CT1 was 5 ± 2 min. CONCLUSIONS: An Atlas for automatic segmentation of lungs in COVID-19 patients was developed and validated. Combined with a previously developed method for lung densitometry characterization, it provides a fast, operator-independent way to extract relevant quantitative parameters with minimal manual intervention.

Venovenous Extracorporeal Membrane Oxygenation in Awake Non-Intubated Patients With COVID-19 ARDS at High Risk for Barotrauma.

OBJECTIVES: To assess the efficacy of an awake venovenous extracorporeal membrane oxygenation (VV-ECMO) management strategy in preventing clinically relevant barotrauma in patients with coronavirus disease 2019 (COVID-19) with severe acute respiratory distress syndrome (ARDS) at high risk for pneumothorax (PNX)/pneumomediastinum (PMD), defined as the detection of the Macklin-like effect on chest computed tomography (CT) scan. DESIGN: A case series. SETTING: At the intensive care unit of a tertiary-care institution. PARTICIPANTS: Seven patients with COVID-19-associated severe ARDS and Macklin-like radiologic sign on baseline chest CT. INTERVENTIONS: Primary VV-ECMO under spontaneous breathing instead of invasive mechanical ventilation (IMV). All patients received noninvasive ventilation or oxygen through a high-flow nasal cannula before and during ECMO support. The study authors collected data on cannulation strategy, clinical management, and outcome. Failure of awake VV-ECMO strategy was defined as the need for IMV due to worsening respiratory failure or delirium/agitation. The primary outcome was the development of PNX/PMD. MEASUREMENTS AND MAIN RESULTS: No patient developed PNX/PMD. The awake VV-ECMO strategy failed in 1 patient (14.3%). Severe complications were observed in 4 (57.1%) patients and were noted as the following: intracranial bleeding in 1 patient (14.3%), septic shock in 2 patients (28.6%), and secondary pulmonary infections in 3 patients (42.8%). Two patients died (28.6%), whereas 5 were successfully weaned off VV-ECMO and were discharged home. CONCLUSIONS: VV-ECMO in awake and spontaneously breathing patients with severe COVID-19 ARDS may be a feasible and safe strategy to prevent the development of PNX/PMD in patients at high risk for this complication.

Macklin effect on baseline chest CT scan accurately predicts barotrauma in COVID-19 patients.

PURPOSE: To validate the role of Macklin effect on chest CT imaging in predicting subsequent occurrence of pneumomediastinum/pneumothorax (PMD/PNX) in COVID-19 patients. MATERIALS AND METHODS: This is an observational, case-control study. Consecutive COVID-19 patients who underwent chest CT scan at hospital admission during the study time period (October 1st, 2020-April 31st, 2021) were identified. Macklin effect accuracy for prediction of spontaneous barotrauma was measured in terms of sensitivity, specificity, positive (PPV) and negative predictive values (NPV). RESULTS: Overall, 981 COVID-19 patients underwent chest CT scan at hospital arrival during the study time period; 698 patients had radiological signs of interstitial pneumonia and were considered for further evaluation. Among these, Macklin effect was found in 33 (4.7%), including all 32 patients who suffered from barotrauma lately during hospital stay (true positive rate: 96.9%); only 1/33 with Macklin effect did not develop barotrauma (false positive rate: 3.1%). No barotrauma event was recorded in patients without Macklin effect on baseline chest CT scan. Macklin effect yielded a sensitivity of 100% (95% CI: 89.1-100), a specificity of 99.85% (95% CI: 99.2-100), a PPV of 96.7% (95% CI: 80.8-99.5), a NPV of 100% and an accuracy of 99.8% (95% CI: 99.2-100) in predicting PMD/PNX, with a mean advance of 3.2 ± 2.5 days. Moreover, all Macklin-positive patients developed ARDS requiring ICU admission and, in 90.1% of cases, invasive mechanical ventilation. CONCLUSIONS: Macklin effect has high accuracy in predicting PMD/PNX in COVID-19 patients; it is also an excellent predictor of disease severity.

One-Year Multidisciplinary Follow-Up of Patients With COVID-19 Requiring Invasive Mechanical Ventilation.

OBJECTIVES: Patients with COVID-19 frequently develop acute respiratory distress syndrome (ARDS) requiring intensive care unit (ICU) admission. Data on long-term survival of these patients are lacking. The authors investigated 1-year survival, quality of life, and functional recovery of patients with COVID-19 ARDS requiring invasive mechanical ventilation. DESIGN: Prospective observational study. SETTING: Tertiary-care university hospital. PARTICIPANTS: All patients with COVID-19 ARDS receiving invasive mechanical ventilation and discharged alive from hospital. INTERVENTIONS: Patients were contacted by phone after 1 year. Functional, cognitive, and psychological outcomes were explored through a questionnaire and assessed using validated scales. Patients were offered the possibility to undergo a follow-up chest computed tomography (CT) scan. MEASUREMENTS AND MAIN RESULTS: The study included all adult (age ≥18 years) patients with COVID-19-related ARDS admitted to an ICU of the authors' institution between February 25, 2020, and April 27, 2020, who received at least 1 day of invasive mechanical ventilation (IMV). Of 116 patients who received IMV, 61 (52.6%) survived to hospital discharge. These survivors were assessed 1 year after discharge and 56 completed a battery of tests of cognition, activities of daily living, and interaction with family members. They had overall good functional recovery, with >80% reporting good recovery and no difficulties in usual activities. A total of 52 (93%) of patients had no dyspnea at rest. Severe anxiety/depression was reported by 5 (8.9%) patients. Comparing 2-month and 1-year data, the authors observed the most significant improvements in the areas of working status and exertional dyspnea. One-year chest CT scans were available for 36 patients; fibrotic-like changes were present in 4 patients. CONCLUSIONS: All patients who survived the acute phase of COVID-19 and were discharged from the hospital were alive at the 1-year follow up, and the vast majority of them had good overall recovery and quality of life.

Case Report: Nintedaninb May Accelerate Lung Recovery in Critical Coronavirus Disease 2019.

Severe Coronavirus disease 2019 (COVID-19) is characterized by acute respiratory distress syndrome (ARDS) which may lead to long-lasting pulmonary sequelae in the survivors. COVID-19 shares common molecular signatures with interstitial lung diseases (ILDs), including pro-angiogenic and tissue-remodeling mechanisms mediated by vascular endothelial growth factor receptor (VEGF-R), fibroblast growth factor receptor (FGF-R), and platelet-derived growth factor receptor (PDGF-R). Nintedanib mainly targets these factors and is approved for ILDs. Therefore, we administered nintedanib through compassionate use to three patients with COVID-19 pneumonia requiring extra-corporeal membrane-oxygenation (ECMO). Here, we describe our experience in an attempt to explore the role of nintedanib in lung recovery in COVID-19. Three obese patients aged between 42 and 52 years were started on nintedanib due to difficulty in obtaining lung function restoration and weaning from ECMO support following the removal of orotracheal intubation (OTI). Soon after the start of the treatment, systemic inflammation and respiratory function rapidly improved and ECMO support was withdrawn. Serial chest CT scans confirmed the progressive lung amelioration, also reflected by functional tests during follow-up. Nintedanib was well-tolerated by all the three patients at the dosage used for ILDs and continued for 2-3 months based on drug availability. Although caution in interpreting events is required; it is tempting to speculate that nintedanib may have contributed to modulate lung inflammation and remodeling and to sustain lung repair. Altogether, nintedanib appears as a promising agent in patients with severe COVID-19 and delayed respiratory function recovery, for whom molecularly targeted therapies are still lacking. Clinical trials are necessary to confirm our observations.

Residual lung damage following ARDS in COVID-19 ICU survivors.

BACKGROUND: Coronavirus disease 2019 acute respiratory distress syndrome (COVID-19 ARDS) is a disease that often requires invasive ventilation. Little is known about COVID-19 ARDS sequelae. We assessed the mid-term lung status of COVID-19 survivors and investigated factors associated with pulmonary sequelae. METHODS: All adult COVID-19 patients admitted to the intensive care unit from 25th February to 27th April 2020 were included. Lung function was evaluated through chest CT scan and pulmonary function tests (PFT). Logistic regression was used to identify predictors of persisting lung alterations. RESULTS: Forty-nine patients (75%) completed lung assessment. Chest CT scan was performed after a median (interquartile range) time of 97 (89-105) days, whilst PFT after 142 (133-160) days. The median age was 58 (52-65) years and most patients were male (90%). The median duration of mechanical ventilation was 11 (6-16) days. Median tidal volume/ideal body weight (TV/IBW) was 6.8 (5.71-7.67) ml/Kg. 59% and 63% of patients showed radiological and functional lung sequelae, respectively. The diffusion capacity of carbon monoxide (DLCO ) was reduced by 59%, with a median per cent of predicted DLCO of 72.1 (57.9-93.9) %. Mean TV/IBW during invasive ventilation emerged as an independent predictor of persistent CT scan abnormalities, whilst the duration of mechanical ventilation was an independent predictor of both CT and PFT abnormalities. The extension of lung involvement at hospital admission (evaluated through Radiographic Assessment of Lung Edema, RALE score) independently predicted the risk of persistent alterations in PFTs. CONCLUSIONS: Both the extent of lung parenchymal involvement and mechanical ventilation protocols predict morphological and functional lung abnormalities months after COVID-19.

Barotrauma in Coronavirus Disease 2019 Patients Undergoing Invasive Mechanical Ventilation: A Systematic Literature Review.

OBJECTIVE: There are concerns of a high barotrauma rate in coronavirus disease 2019 patients with acute respiratory distress syndrome receiving invasive mechanical ventilation. However, a few studies were published, and reported rates were highly variable. We performed a systematic literature review to identify rates of barotrauma, pneumothorax, and pneumomediastinum in coronavirus disease 2019 acute respiratory distress syndrome patients receiving invasive mechanical ventilation. DATA SOURCE: PubMed and Scopus were searched for studies reporting barotrauma event rate in adult coronavirus disease 2019 patients receiving invasive mechanical ventilation. STUDY SELECTION: We included all studies investigating adult patients with coronavirus disease 2019 acute respiratory distress syndrome requiring mechanical ventilation. Case reports, studies performed outside ICU setting, and pediatric studies were excluded. Two investigators independently screened and selected studies for inclusion. DATA EXTRACTION: Two investigators abstracted data on study characteristics, rate of pneumothorax, pneumomediastinum and overall barotrauma events, and mortality. When available, data from noncoronavirus disease 2019 acute respiratory distress syndrome patients were also collected. Pooled estimates for barotrauma, pneumothorax, and pneumomediastinum were calculated. DATA SYNTHESIS: A total of 13 studies with 1,814 invasively ventilated coronavirus disease 2019 patients and 493 noncoronavirus disease 2019 patients were included. A total of 266/1,814 patients (14.7%) had at least one barotrauma event (pooled estimates, 16.1% [95% CI, 11.8-20.4%]). Pneumothorax occurred in 132/1,435 patients (pooled estimates, 10.7%; 95% CI, 6.7-14.7%), whereas pneumomediastinum occurred in 162/1,432 patients (pooled estimates, 11.2%; 95% CI, 8.0-14.3%). Mortality in coronavirus disease 2019 patients who developed barotrauma was 111/198 patients (pooled estimates, 61.6%; 95% CI, 50.2-73.0%). In noncoronavirus disease 2019 acute respiratory distress syndrome patients, barotrauma occurred in 31/493 patients (6.3%; pooled estimates, 5.7%; 95% CI, -2.1% to 13.5%). CONCLUSIONS: Barotrauma occurs in one out of six coronavirus disease 2019 acute respiratory distress syndrome patients receiving invasive mechanical ventilation and is associated with a mortality rate of about 60%. Barotrauma rate may be higher than noncoronavirus disease 2019 controls.

A radiological predictor for pneumomediastinum/pneumothorax in COVID-19 ARDS patients.

PURPOSE: To determine whether Macklin effect (a linear collection of air contiguous to the bronchovascular sheath) on baseline CT imaging is an accurate predictor for subsequent pneumomediastinum (PMD)/pneumothorax (PNX) development in invasively ventilated patients with COVID-19-related acute respiratory distress syndrome (ARDS). MATERIALS AND METHODS: This is an observational, case-control study. From a prospectively acquired database, all consecutive invasively ventilated COVID-19 ARDS patients who underwent at least one baseline chest CT scan during the study time period (February 25th, 2020-December 31st, 2020) were identified; those who had tracheal lesion or already had PMD/PNX at the time of the first available chest imaging were excluded. RESULTS: 37/173 (21.4%) patients enrolled had PMD/PNX; specifically, 20 (11.5%) had PMD, 10 (5.8%) PNX, 7 (4%) both. 33/37 patients with subsequent PMD/PNX had Macklin effect on baseline CT (89.2%, true positives) 8.5 days [range, 1-18] before the first actual radiological evidence of PMD/PNX. Conversely, 6/136 patients without PMD/PNX (4.4%, false positives) demonstrated Macklin effect (p < 0.001). Macklin effect yielded a sensitivity of 89.2% (95% confidence interval [CI]: 74.6-96.9), a specificity of 95.6% (95% CI: 90.6-98.4), a positive predictive value (PV) of 84.5% (95% CI: 71.3-92.3), a negative PV of 97.1% (95% CI: 74.6-96.9) and an accuracy of 94.2% (95% CI: 89.6-97.2) in predicting PMD/PNX (AUC:0.924). CONCLUSIONS: Macklin effect accurately predicts, 8.5 days in advance, PMD/PNX development in COVID-19 ARDS patients.

Quantitative assessment of lung involvement on chest CT at admission: Impact on hypoxia and outcome in COVID-19 patients.

BACKGROUND: The aim of this study was to quantify COVID-19 pneumonia features using CT performed at time of admission to emergency department in order to predict patients' hypoxia during the hospitalization and outcome. METHODS: Consecutive chest CT performed in the emergency department between March 1st and April 7th 2020 for COVID-19 pneumonia were analyzed. The three features of pneumonia (GGO, semi-consolidation and consolidation) and the percentage of well-aerated lung were quantified using a HU threshold based software. ROC curves identified the optimal cut-off values of CT parameters to predict hypoxia worsening and hospital discharge. Multiple Cox proportional hazards regression was used to analyze the capability of CT quantitative features, demographic and clinical variables to predict the time to hospital discharge. RESULTS: Seventy-seven patients (median age 56-years-old, 51 men) with COVID-19 pneumonia at CT were enrolled. The quantitative features of COVID-19 pneumonia were not associated to age, sex and time-from-symptoms onset, whereas higher number of comorbidities was correlated to lower well-aerated parenchyma ratio (rho = -0.234, p = 0.04) and increased semi-consolidation ratio (rho = -0.303, p = 0.008). Well-aerated lung (≤57%), semi-consolidation (≥17%) and consolidation (≥9%) predicted worst hypoxemia during hospitalization, with moderate areas under curves (AUC 0.76, 0.75, 0.77, respectively). Multiple Cox regression identified younger age (p < 0.01), female sex (p < 0.001), longer time-from-symptoms onset (p = 0.049), semi-consolidation ≤17% (p < 0.01) and consolidation ≤13% (p = 0.03) as independent predictors of shorter time to hospital discharge. CONCLUSION: Quantification of pneumonia features on admitting chest CT predicted hypoxia worsening during hospitalization and time to hospital discharge in COVID-19 patients.

Robust prediction of mortality of COVID-19 patients based on quantitative, operator-independent, lung CT densitometry.

PURPOSE: To train and validate a predictive model of mortality for hospitalized COVID-19 patients based on lung densitometry. METHODS: Two-hundred-fifty-one patients with respiratory symptoms underwent CT few days after hospitalization. "Aerated" (AV), "consolidated" (CV) and "intermediate" (IV) lung sub-volumes were quantified by an operator-independent method based on individual HU maximum gradient recognition. AV, CV, IV, CV/AV, IV/AV, and HU of the first peak position were extracted. Relevant clinical parameters were prospectively collected. The population was composed by training (n = 166) and validation (n = 85) consecutive cohorts, and backward multi-variate logistic regression was applied on the training group to build a CT_model. Similarly, models including only clinical parameters (CLIN_model) and both CT/clinical parameters (COMB_model) were developed. Model's performances were assessed by goodness-of-fit (H&L-test), calibration and discrimination. Model's performances were tested in the validation group. RESULTS: Forty-three patients died (25/18 in training/validation). CT_model included AVmax (i.e. maximum AV between lungs), CV and CV/AE, while CLIN_model included random glycemia, C-reactive protein and biological drugs (protective). Goodness-of-fit and discrimination were similar (H&L:0.70 vs 0.80; AUC:0.80 vs 0.80). COMB_model including AVmax, CV, CV/AE, random glycemia, biological drugs and active cancer, outperformed both models (H&L:0.91; AUC:0.89, 95%CI:0.82-0.93). All models showed good calibration (R2:0.77-0.97). Despite several patient's characteristics were different between training and validation cohorts, performances in the validation cohort confirmed good calibration (R2:0-70-0.81) and discrimination for CT_model/COMB_model (AUC:0.72/0.76), while CLIN_model performed worse (AUC:0.64). CONCLUSIONS: Few automatically extracted densitometry parameters with clear functional meaning predicted mortality of COVID-19 patients. Combined with clinical features, the resulting predictive model showed higher discrimination/calibration.