G. Kim Prisk’s research while affiliated with University of California, San Diego and other places

INTRODUCTION AI deep learning algorithms trained on non-contrast CT scans effectively detect and quantify acute COVID-19 lung involvement. Our study explored whether radiological contrast affects the accuracy of AI-measured lung opacities, potentially impacting clinical decisions. We compared lung opacity measurements from AI software with visual assessments by radiologists using CTPA images of early-stage COVID-19 patients. MATERIAL AND METHODS This prospective single-center study included 18 COVID-19 patients who underwent CTPA due to suspected pulmonary embolism. Patient demographics, clinical data, and 30-day and 90-day mortality were recorded. AI tool (Pulmonary Density Plug-in, AI-Rad Companion Chest CT, SyngoVia, Siemens Healthineers) was used to estimate the quantity of opacities. Visual quantitative assessments were performed independently by two radiologists. RESULTS There was a positive correlation between radiologist estimations (r2 = 0.57) and between the AI data and the mean of the radiologists’ estimations (r2 = 0.70). Bland-Altman plot analysis showed a mean bias of + 3.06% between radiologists and -1.32% between the mean radiologist vs AI, with no outliers outside 2xSD for respective comparison. DISCUSSION The AI protocol facilitated a quantitative assessment of lung opacities and showed a strong correlation with data obtained from two independent radiologists, demonstrating its potential as a complementary tool in clinical practice. CONCLUSION In assessing COVID-19 lung opacities in CTPA images, AI tools trained on non-contrast images, provide comparable results to visual assessments by radiologists. ADVANCES IN KNOWLEDGE The Pulmonary Density Plug-in enables quantitative analysis of lung opacities in COVID-19 patients using contrast-enhanced CT images, potentially streamlining clinical workflows and supporting timely decision-making.

Vaping use has skyrocketed especially among young adults, however there is no consensus on how vaping impacts the lungs. We aimed to determine whether there were changes in lung function acutely after a standard vaping session or if there were differences in lung function metrics between a healthy never‐vaping cohort (N = 6; 27.3 ± 3.0 years) and a young asymptomatic vaping cohort (N = 14; 26.4 ± 8.0 years) indicating chronic changes. Pulmonary function measurements and impulse oscillometry were obtained on all participants. Oxygen‐enhanced and Arterial Spin Labelling MRI were used to measure specific ventilation and perfusion, respectively, before and after vaping, and in the control cohort at baseline. MRI metrics did not show any significant differences in specific ventilation or perfusion after vaping. Heart rate increased post‐vaping (68.1 ± 10.5 to 71.3 ± 8.7, p = 0.020); however, this and other metrics did not show a nicotine dose‐dependent effect. There was a significant negative correlation between BMI and change in mean perfusion post‐vaping (p = 0.003); those with normal/low BMI showing an increase in perfusion and vice versa for high BMI. This may be due to subjects lying supine during vaping inhalation. Pulmonary function metrics indicative of airways resistance showed significant differences between the vaping and control cohorts indicating early airway changes.

In some patients with acute respiratory distress syndrome (ARDS), a paradoxical improvement in respiratory system compliance (C RS ) has been observed when assuming a supine (head of bed [HOB] 0°) compared with semirecumbent (HOB 35–40°) posture. We sought to test the hypothesis that mechanically ventilated patients with ARDS would have improved C RS , due to changes in ventilation distribution, when moving from the semirecumbent to supine position. We conducted a prospective, observational ICU study including 14 mechanically ventilated patients with ARDS. For each patient, ventilation distribution (assessed by electrical impedance tomography) and pulmonary mechanics were compared in supine versus semirecumbent postures. Compared with semirecumbent, in the supine posture C RS increased (33 ± 21 vs. 26 ± 14 mL/cm H 2 O, p = 0.005), driving pressure was reduced (14 ± 6 vs. 17 ± 7 cm H 2 O, p < 0.001), and dorsal fraction of ventilation was decreased (48.5 ± 14.1% vs. 54.5 ± 12.0%, p = 0.003). Posture change from semirecumbent to supine resulted in a favorable physiologic response in terms of improved C RS and reduced driving pressure—with a corresponding increase in ventral ventilation, possibly related to reduced ventral overdistension.

Increased intrapulmonary shunt(Q S /Q t ) and alveolar dead space(V D /V T ) are present in early recovery from COVID-19. We hypothesized patients recovering from severe-critical acute illness(NIH category 3-5) would have greater and longer-lasting increased Q S /Q t and V D /V T than patients with mild-moderate acute illness(NIH 1-2). Methods: 59 unvaccinated patients (33 male, age 52[38-61] years, BMI 28.8[25.3-33.6] kg/m ² ; median[IQR], 44 previous mild-moderate COVID-19, and 15 severe-critical disease), were studied 15-403 days post-acute SARS-CoV-2 infection. Breathing ambient air, steady-state mean alveolar PCO 2 and PO 2 were recorded simultaneously with arterial PO 2 /PCO 2 yielding aAPCO 2 , AaPO 2 , and from these, Q S /Q t %, V D /V T %, and relative alveolar ventilation (40 mmHg/P A CO 2 , V A rel) calculated. Results: Median PaCO 2 was 39.4[35.6-41.1] mmHg, PaO 2 92.3[87.1-98.2mmHg; P A CO 2 32.8[28.6-35.3] mmHg, P A O 2 112.9[109.4-117.0] mmHg, AaPO 2 18.8[12.6-26.8] mmHg, aAPCO 2 5.9 [4.3-8.0] mmHg, Q S /Q t 4.3 [2.1-5.9] % and V D /V T 16.6 [12.6-24.4] %. Only 14% of patients had normal Q S /Q t and V D /V T ;1% increased Q S /Q t but normal V D /V T ; 49% normal Q S /Q t and elevated V D /V T ;36% both abnormal Q S /Q t and V D /V T . Previous severe-critical COVID-19 predicted increased Q S /Q t (2.69 [0.82-4.57]% per category severity [95% CI], p<0.01), but not V D /V T . Increasing age weakly predicted increased V D /V T (1.6 [0.1-3.2]% per decade, p<0.04). Time since infection, BMI and comorbidities were not predictors (all p > 0.11). V A rel was increased in most patients. Conclusions: In our population, recovery from COVID-19 was associated with increased Q S /Q t in 37% of patients, increased V D /V T in 86%, and increased alveolar ventilation up to ~13 months post infection. NIH severity predicted Q S /Q t but not elevated V D /V T . Increased V D /V T suggests pulmonary micro-vascular pathology persists post COVID-19 in most patients.

Background and objective: The COVID-19 pandemic magnified the importance of gas exchange abnormalities in early respiratory failure. Pulse oximetry (SpO2) has not been universally effective for clinical decision-making, possibly because of limitations. The alveolar gas monitor (AGM100) adds exhaled gas tensions to SpO2 to calculate the oxygen deficit (OD). The OD parallels the alveolar-to-arterial oxygen difference (AaDO2) in outpatients with cardiopulmonary disease. We hypothesized that the OD would discriminate between COVID-19 patients who require hospital admission and those who are discharged home, as well as predict need for supplemental oxygen during the index hospitalization. Methods: Patients presenting with dyspnea and COVID-19 were enrolled with informed consent and had OD measured using the AGM100. The OD was then compared between admitted and discharged patients and between patients who required supplemental oxygen and those who did not. The OD was also compared to SpO2 for each of these outcomes using receiver operating characteristic (ROC) curves. Results: Thirty patients were COVID-19 positive and had complete AGM100 data. The mean OD was significantly (p = 0.025) higher among those admitted 50.0 ± 20.6 (mean ± SD) vs. discharged 27.0 ± 14.3 (mean ± SD). The OD was also significantly (p < 0.0001) higher among those requiring supplemental oxygen 60.1 ± 12.9 (mean ± SD) vs. those remaining on room air 25.2 ± 11.9 (mean ± SD). ROC curves for the OD demonstrated very good and excellent sensitivity for predicting hospital admission and supplemental oxygen administration, respectively. The OD performed better than an SpO2 threshold of <94%. Conclusions: The AGM100 is a novel, noninvasive way of measuring impaired gas exchange for clinically important endpoints in COVID-19.