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Causes of Hypoxemia in COVID-19 Acute Respiratory Distress Syndrome: A Combined Multiple Inert Gas Elimination Technique and Dual-energy Computed Tomography Study.
Busana, Mattia; Rau, Anna; Lazzari, Stefano; Gattarello, Simone; Cressoni, Massimo; Biggemann, Lorenz; Harnisch, Lars-Olav; Giosa, Lorenzo; Vogt, Andreas; Saager, Leif; Lotz, Joachim; Meller, Birgit; Meissner, Konrad; Gattinoni, Luciano; Moerer, Onnen.
Affiliation
  • Busana M; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany.
  • Rau A; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany.
  • Lazzari S; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany; and Institute for Treatment and Research San Raffaele Scientific Institute, Department of Anesthesia and Intensive Care, Milan, Italy.
  • Gattarello S; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany; and Institute for Treatment and Research San Raffaele Scientific Institute, Department of Anesthesia and Intensive Care, Milan, Italy.
  • Cressoni M; Unit of Radiology, Institute for Treatment and Research Policlinico San Donato, Milan, Italy.
  • Biggemann L; Institute for Diagnostic and Interventional Radiology, University Medical Center of Göttingen, Göttingen, Germany.
  • Harnisch LO; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany.
  • Giosa L; Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom.
  • Vogt A; Department of Anaesthesiology and Pain Medicine, Bern University Hospital, University of Bern, Bern, Switzerland.
  • Saager L; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany; and Outcomes Research Consortium, Cleveland, Ohio.
  • Lotz J; Institute for Diagnostic and Interventional Radiology, University Medical Center of Göttingen, Göttingen, Germany.
  • Meller B; Clinic of Nuclear Medicine, University Medical Center of Göttingen, Göttingen, Germany.
  • Meissner K; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany.
  • Gattinoni L; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany.
  • Moerer O; Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany.
Anesthesiology ; 140(2): 251-260, 2024 Feb 01.
Article in En | MEDLINE | ID: mdl-37656772
BACKGROUND: Despite the fervent scientific effort, a state-of-the art assessment of the different causes of hypoxemia (shunt, ventilation-perfusion mismatch, and diffusion limitation) in COVID-19 acute respiratory distress syndrome (ARDS) is currently lacking. In this study, the authors hypothesized a multifactorial genesis of hypoxemia and aimed to measure the relative contribution of each of the different mechanism and their relationship with the distribution of tissue and blood within the lung. METHODS: In this cross-sectional study, the authors prospectively enrolled 10 patients with COVID-19 ARDS who had been intubated for less than 7 days. The multiple inert gas elimination technique (MIGET) and a dual-energy computed tomography (DECT) were performed and quantitatively analyzed for both tissue and blood volume. Variables related to the respiratory mechanics and invasive hemodynamics (PiCCO [Getinge, Sweden]) were also recorded. RESULTS: The sample (51 ± 15 yr; Pao2/Fio2, 172 ± 86 mmHg) had a mortality of 50%. The MIGET showed a shunt of 25 ± 16% and a dead space of 53 ± 11%. Ventilation and perfusion were mismatched (LogSD, Q, 0.86 ± 0.33). Unexpectedly, evidence of diffusion limitation or postpulmonary shunting was also found. In the well aerated regions, the blood volume was in excess compared to the tissue, while the opposite happened in the atelectasis. Shunt was proportional to the blood volume of the atelectasis (R2 = 0.70, P = 0.003). V˙A/Q˙T mismatch was correlated with the blood volume of the poorly aerated tissue (R2 = 0.54, P = 0.016). The overperfusion coefficient was related to Pao2/Fio2 (R2 = 0.66, P = 0.002), excess tissue mass (R2 = 0.84, P < 0.001), and Etco2/Paco2 (R2 = 0.63, P = 0.004). CONCLUSIONS: These data support the hypothesis of a highly multifactorial genesis of hypoxemia. Moreover, recent evidence from post-mortem studies (i.e., opening of intrapulmonary bronchopulmonary anastomosis) may explain the findings regarding the postpulmonary shunting. The hyperperfusion might be related to the disease severity.
Subject(s)

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Respiratory Distress Syndrome / Pulmonary Atelectasis / COVID-19 Type of study: Etiology_studies / Prognostic_studies Limits: Humans Language: En Journal: Anesthesiology Year: 2024 Document type: Article Affiliation country: Country of publication:

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Respiratory Distress Syndrome / Pulmonary Atelectasis / COVID-19 Type of study: Etiology_studies / Prognostic_studies Limits: Humans Language: En Journal: Anesthesiology Year: 2024 Document type: Article Affiliation country: Country of publication: