Esophageal pressure as estimation of pleural pressure: a study in a model of eviscerated chest.

Background: Transpulmonary pressure is the effective pressure across the lung parenchyma and has been proposed as a guide for mechanical ventilation. The pleural pressure is challenging to directly measure in clinical setting and esophageal manometry using esophageal balloon catheters was suggested for estimation. However, the accuracy of using esophageal pressure to estimate pleural pressure is debated due to variability in the mechanical properties of respiratory system, esophagus and esophageal catheter.

A tidal volume of 7 mL/kg PBW or higher may be safe for COVID-19 patients.

Purpose: The novel coronavirus disease (COVID-19) has revived the debate on the optimal tidal volume during acute respiratory distress syndrome (ARDS). Some experts recommend 6 mL/kg of predicted body weight (PBW) for all patients, while others suggest 7-9 mL/kg PBW for those with compliance >50 mL/cmHO. We investigated whether a tidal volume ≥ 7 ml/kg PBW may be safe in COVID-19 patients, particularly those with compliance >50 mL/cmHO.

Signs of Hemolysis Predict Mortality and Ventilator Associated Pneumonia in Severe Acute Respiratory Distress Syndrome Patients Undergoing Veno-Venous Extracorporeal Membrane Oxygenation.

Cell-free hemoglobin (CFH) is used to detect hemolysis and was recently suggested to trigger acute lung injury. However, its role has not been elucidated in severe acute respiratory distress syndrome (ARDS) patients undergoing extracorporeal membrane oxygenation (ECMO). We investigated the association of carboxyhemoglobin (COHb) and haptoglobin-two indirect markers of hemolysis-with mortality in critically ill patients undergoing veno-venous ECMO (VV-ECMO) with adjusted and longitudinal models (primary aim).

Medical occurrence and safety of SARS-CoV-2 vaccination outside of the hospital setting.

During COVID-19 pandemic, vaccination has been strongly recommended and advocated to prevent COVID-19 infection and adverse outcomes, particularly among at-risk populations. The vaccination against SARS-CoV-2 (COVAC) occurred at off-site locations capable of accommodating large crowds, distinct from the hospital setting, where a team of intensivists, emergency physicians, and nurses, ensuring prompt medical attention (medical occurrences, MO) in cases of adverse event following immunization. Our aims were to estimate the incidence of MO, and to assess its association with demographics, and vaccine characteristics.

Impact of Positive End-Expiratory Pressure and FiO on Lung Mechanics and Intrapulmonary Shunt in Mechanically Ventilated Patients with ARDS Due to COVID-19 Pneumonia.

This study aimed to investigate the effects of inspired oxygen fraction (FiO) and positive end-expiratory pressure (PEEP) on gas exchange in mechanically ventilated patients with COVID-19. Two FiO (100%, 40%) were tested at 3 decreasing levels of PEEP (15, 10, and 5 cmHO). At each FiO and PEEP, gas exchange, respiratory mechanics, hemodynamics, and the distribution of ventilation and perfusion were assessed with electrical impedance tomography.

Association of COVID-19 Vaccinations With Intensive Care Unit Admissions and Outcome of Critically Ill Patients With COVID-19 Pneumonia in Lombardy, Italy.

Importance: Data on the association of COVID-19 vaccination with intensive care unit (ICU) admission and outcomes of patients with SARS-CoV-2-related pneumonia are scarce.

Objective: To evaluate whether COVID-19 vaccination is associated with preventing ICU admission for COVID-19 pneumonia and to compare baseline characteristics and outcomes of vaccinated and unvaccinated patients admitted to an ICU.

Design, Setting, And Participants: This retrospective cohort study on regional data sets reports: (1) daily number of administered vaccines and (2) data of all consecutive patients admitted to an ICU in Lombardy, Italy, from August 1 to December 15, 2021 (Delta variant predominant).

Time course of risk factors associated with mortality of 1260 critically ill patients with COVID-19 admitted to 24 Italian intensive care units.

Purpose: To evaluate the daily values and trends over time of relevant clinical, ventilatory and laboratory parameters during the intensive care unit (ICU) stay and their association with outcome in critically ill patients with coronavirus disease 19 (COVID-19).

Methods: In this retrospective-prospective multicentric study, we enrolled COVID-19 patients admitted to Italian ICUs from February 22 to May 31, 2020. Clinical data were daily recorded.

Sharing Mechanical Ventilator: In Vitro Evaluation of Circuit Cross-Flows and Patient Interactions.

During the COVID-19 pandemic, a shortage of mechanical ventilators was reported and ventilator sharing between patients was proposed as an ultimate solution. Two lung simulators were ventilated by one anesthesia machine connected through two respiratory circuits and T-pieces. Five different combinations of compliances (30-50 mL × cmHO) and resistances (5-20 cmHO × L × s) were tested.

Alkaline Liquid Ventilation of the Membrane Lung for Extracorporeal Carbon Dioxide Removal (ECCOR): In Vitro Study.

Extracorporeal carbon dioxide removal (ECCOR) is a promising strategy to manage acute respiratory failure. We hypothesized that ECCOR could be enhanced by ventilating the membrane lung with a sodium hydroxide (NaOH) solution with high CO absorbing capacity. A computed mathematical model was implemented to assess NaOH-CO interactions.

Low noncarbonic buffer power amplifies acute respiratory acid-base disorders in patients with sepsis: an in vitro study.

Patients with sepsis have typically reduced concentrations of hemoglobin and albumin, the major components of noncarbonic buffer power (). This could expose patients to high pH variations during acid-base disorders. The objective of this study is to compare, in vitro, noncarbonic of patients with sepsis with that of healthy volunteers, and evaluate its distinct components.

Pulmonary volume-feedback and ventilatory pattern after bilateral lung transplantation using neurally adjusted ventilatory assist ventilation.

Background: Bilateral lung transplantation results in pulmonary vagal denervation, which potentially alters respiratory drive, volume-feedback, and ventilatory pattern. We hypothesised that Neurally Adjusted Ventilatory Assist (NAVA) ventilation, which is driven by diaphragm electrical activity (EAdi), would reveal whether vagally mediated pulmonary-volume feedback is preserved in the early phases after bilateral lung transplantation.

Methods: We prospectively studied bilateral lung transplant recipients within 48 h of surgery.

Prone position in intubated, mechanically ventilated patients with COVID-19: a multi-centric study of more than 1000 patients.

Background: Limited data are available on the use of prone position in intubated, invasively ventilated patients with Coronavirus disease-19 (COVID-19). Aim of this study is to investigate the use and effect of prone position in this population during the first 2020 pandemic wave.

Methods: Retrospective, multicentre, national cohort study conducted between February 24 and June 14, 2020, in 24 Italian Intensive Care Units (ICU) on adult patients needing invasive mechanical ventilation for respiratory failure caused by COVID-19.

Quantification of Recirculation During Veno-Venous Extracorporeal Membrane Oxygenation: In Vitro Evaluation of a Thermodilution Technique.

Veno-venous extracorporeal membrane oxygenation (vv-ECMO) represents one of the most advanced respiratory support for patients suffering from severe acute respiratory distress syndrome. During vv-ECMO a certain amount of extracorporeal oxygenated blood can flow back from the reinfusion into the drainage cannula without delivering oxygen to the patient. Detection and quantification of this dynamic phenomenon, defined recirculation, are critical to optimize the ECMO efficiency.

Key Role of Respiratory Quotient to Reduce the Occurrence of Hypoxemia During Extracorporeal Gas Exchange: A Theoretical Analysis.

Objectives: Extracorporeal respiratory support, including low blood flow systems providing mainly extracorporeal CO2 removal, are increasingly applied in clinical practice. Gas exchange physiology during extracorporeal respiratory support is complex and differs between full extracorporeal membrane oxygenation and extracorporeal CO2 removal. Aim of the present article is to review pathophysiological aspects which are relevant for the understanding of hypoxemia development during extracorporeal CO2 removal.

Risk Factors Associated With Mortality Among Patients With COVID-19 in Intensive Care Units in Lombardy, Italy.

Importance: Many patients with coronavirus disease 2019 (COVID-19) are critically ill and require care in the intensive care unit (ICU).

Objective: To evaluate the independent risk factors associated with mortality of patients with COVID-19 requiring treatment in ICUs in the Lombardy region of Italy.

Design, Setting, And Participants: This retrospective, observational cohort study included 3988 consecutive critically ill patients with laboratory-confirmed COVID-19 referred for ICU admission to the coordinating center (Fondazione IRCCS [Istituto di Ricovero e Cura a Carattere Scientifico] Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy) of the COVID-19 Lombardy ICU Network from February 20 to April 22, 2020.

Extracorporeal support to achieve lung-protective and diaphragm-protective ventilation.

Purpose Of Review: Extracorporeal support allows ultraprotective controlled and assisted ventilation, which can prevent lung and diaphragm injury. We focused on most recent findings in the application of extracorporeal support to achieve lung protection and diaphragm- protection, as well as on relevant monitoring.

Recent Findings: A recent randomized trial comparing the efficacy of extracorporeal support as a rescue therapy to conventional protective mechanical ventilation was stopped for futility but post hoc analyses suggested that extracorporeal support is beneficial for patients with very severe acute respiratory distress syndrome.

Time-Course of Physiologic Variables During Extracorporeal Membrane Oxygenation and Outcome of Severe Acute Respiratory Distress Syndrome.

In patients undergoing extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS), it is unknown which clinical physiologic variables should be monitored to follow the evolution of lung injury and extrapulmonary organ dysfunction and to differentiate patients according to their course. We analyzed the time-course of prospectively collected clinical physiologic variables in 83 consecutive ARDS patients undergoing ECMO at a single referral center. Selected variables-including ventilator settings, respiratory system compliance, intrapulmonary shunt, arterial blood gases, central hemodynamics, and sequential organ failure assessment (SOFA) score-were compared according to outcome at time-points corresponding to 0%, 25%, 50%, 75%, and 100% of the entire ECMO duration and daily during the first 7 days.

Increasing support by nasal high flow acutely modifies the ROX index in hypoxemic patients: A physiologic study.

The ROX (Respiratory rate-OXygenation) index is an early predictor of failure of nasal high flow (NHF), with lower values indicating higher risk of intubation. We measured the ROX index at set flow rate of 30 and 60 l/min in 57 hypoxemic patients on NHF. Patients with increased ROX index values at higher flow (n = 40) showed worse baseline oxygenation, higher respiratory rate and lower ROX index in comparison to patients with unchanged or decreased ROX index values (n = 17).

An Artificial Cough Maneuver to Remove Secretions From Below the Endotracheal Tube Cuff.

Background: Endotracheal suctioning is mandatory to prevent complications caused by the retention of tracheal secretions. Endotracheal suctioning is often performed late, when patients show signs of respiratory and hemodynamic alterations. We conceived a prototype device that, when synchronized with the ventilator, automatically removes secretions collected below the endotracheal tube (ETT) cuff, thus avoiding endotracheal suctioning.

Impact of flow and temperature on patient comfort during respiratory support by high-flow nasal cannula.

Background: The high-flow nasal cannula (HFNC) delivers up to 60 l/min of humidified air/oxygen blend at a temperature close to that of the human body. In this study, we tested whether higher temperature and flow decrease patient comfort. In more severe patients, instead, we hypothesized that higher flow might be associated with improved comfort.

Ventilation during extracorporeal support : Why and how.

The main target of extracorporeal support is to achieve viable gas exchange, while minimizing the risk of ventilator-induced lung injury, achieved through a decreased mechanical ventilation load on the natural lung. However, during veno-venous extracorporeal membrane oxygenation (ECMO), mechanical ventilation is still necessary in order to prevent lung collapse and/or if extracorporeal blood flow is not sufficient to guarantee adequate gas exchange. In this review, we will summarize the physiology of extracorporeal support and the rationale for continuing mechanical ventilation in this context.

Optimum support by high-flow nasal cannula in acute hypoxemic respiratory failure: effects of increasing flow rates.

Purpose: Limited data exist on the correlation between higher flow rates of high-flow nasal cannula (HFNC) and its physiologic effects in patients with acute hypoxemic respiratory failure (AHRF). We assessed the effects of HFNC delivered at increasing flow rate on inspiratory effort, work of breathing, minute ventilation, lung volumes, dynamic compliance and oxygenation in AHRF patients.

Methods: A prospective randomized cross-over study was performed in non-intubated patients with patients AHRF and a PaO/FiO (arterial partial pressure of oxygen/fraction of inspired oxygen) ratio of ≤300 mmHg.