Physiological Consequences of Breathing Effort According to the Mode of Ventilation During Acute Hypoxemic Respiratory Failure.

Rationale: Excessive stress (distending pressure), strain (volume deformation), and drop in inspiratory alveolar pressure are proposed mechanisms for patient self-inflicted lung injury.

Objectives: To dissect the influence of inspiratory effort, respiratory mechanics, and ventilation mode on lung stress, strain, and drop in inspiratory alveolar pressure; and explore their impact on oxygenation and lung compliance.

Methods: International cohort study analyzing respiratory recordings (esophageal pressure) of patients with acute hypoxemic respiratory failure.

Erroneous calibration of esophageal pressure in case of airway closure.

Airway closure results in a lack of communication between proximal and distal airways unless the airway pressure (Paw) overcomes the airway opening pressure (AOP). This has been described in patients undergoing mechanical ventilation with acute respiratory distress syndrome, obesity, hydrostatic pulmonary edema and during cardiopulmonary resuscitation. In these categories of patients, esophageal pressure (Pes) can guide the personalization of mechanical ventilation and calibration of the esophageal balloon is necessary to obtain reliable Pes measurements.

Accuracy of Real-Time Data Provided by Mechanical Insufflation-Exsufflation Devices.

Mechanical insufflation-exsufflation (MI-E) is crucial to assist patients with impaired cough, especially those with neuromuscular diseases. Despite recent advancements that enable real-time display of peak expiratory flow (PEF) and inspiratory volume, accurately monitoring these parameters with MI-E devices during treatment can still present challenges. A bench study that used a mechanical lung connected to 3 MI-E devices (EOVE-70; E-70 and Comfort Cough II) was conducted to evaluate PEF and inspiratory volume monitoring accuracy.

Effect of high-flow nasal cannula oxygen versus standard oxygen on mortality in patients with acute hypoxaemic respiratory failure: protocol for a multicentre, randomised controlled trial (SOHO).

Introduction: First-line oxygenation strategy in patients with acute hypoxaemic respiratory failure consists in standard oxygen or high-flow nasal oxygen therapy. Clinical practice guidelines suggest the use of high-flow nasal oxygen rather than standard oxygen. However, findings remain contradictory with a low level of certainty.

Pressure control plus spontaneous ventilation versus volume assist-control ventilation in acute respiratory distress syndrome. A randomised clinical trial.

Purpose: The aim of this study was to compare the effect of a pressure-controlled strategy allowing non-synchronised unassisted spontaneous ventilation (PC-SV) to a conventional volume assist-control strategy (ACV) on the outcome of patients with acute respiratory distress syndrome (ARDS).

Methods: Open-label randomised clinical trial in 22 intensive care units (ICU) in France. Seven hundred adults with moderate or severe ARDS (PaO/FiO < 200 mmHg) were enrolled from February 2013 to October 2018.

Modes of administration of nitric oxide devices and ventilators flow-by impact the delivery of pre-determined concentrations.

Background: Nitric oxide (NO) is a strong vasodilator, selectively directed on pulmonary circulation through inhaled administration. In adult intensive care units (ICU), it is mainly used for refractory hypoxemia in mechanically ventilated patients. Several medical delivery devices have been developed to deliver inhaled nitric oxide (iNO).

A new physiological manikin to test and compare ventilation devices during cardiopulmonary resuscitation.

Background: There is a lack of bench systems permitting to evaluate ventilation devices in the specific context of cardiac arrest.

Objectives: The objective of the study is to assess if a new physiological manikin may permit to evaluate the performances of medical devices dedicated to ventilation during cardiopulmonary resuscitation (CPR).

Methods: Specific CPR-related features required to reproduce realistic ventilation were implemented into the SAM (Sarthe Anjou Mayenne) manikin.

Bedside personalized methods based on electrical impedance tomography or respiratory mechanics to set PEEP in ARDS and recruitment-to-inflation ratio: a physiologic study.

Background: Various Positive End-Expiratory Pressure (PEEP) titration strategies have been proposed to optimize ventilation in patients with acute respiratory distress syndrome (ARDS). We aimed to compare PEEP titration strategies based on electrical impedance tomography (EIT) to methods derived from respiratory system mechanics with or without esophageal pressure measurements, in terms of PEEP levels and association with recruitability.

Methods: Nineteen patients with ARDS were enrolled.

3-Methylmethcathinone Intoxication: Discrepancies Between Blood Concentrations and Clinical Outcomes-A Short Communication.

Background: The absence of a correlation between the blood concentration of 3-methylmethcathinone (3-MMC) and clinical outcomes in intoxication cases has been attributed to stability issues. Indeed, a loss of more than 50%, 70%, and even 95% of 3-MMC in whole blood after 2 weeks of storage at 20°C, 4°C, and room temperature, respectively, has been reported in the past. Here, the authors report the case of a 43-year-old man who was hospitalized with generalized convulsive status epilepticus related to 3-MMC use with a plasma concentration of 9600 ng/mL (delay between sampling and analysis <72 hours).

Advanced respiratory mechanics assessment in mechanically ventilated obese and non-obese patients with or without acute respiratory distress syndrome.

Background: Respiratory mechanics is a key element to monitor mechanically ventilated patients and guide ventilator settings. Besides the usual basic assessments, some more complex explorations may allow to better characterize patients' respiratory mechanics and individualize ventilation strategies. These advanced respiratory mechanics assessments including esophageal pressure measurements and complete airway closure detection may be particularly relevant in critically ill obese patients.

A novel method for assessment of airway opening pressure without the need for low-flow insufflation.

Background: Airway opening pressure (AOP) detection and measurement are essential for assessing respiratory mechanics and adapting ventilation. We propose a novel approach for AOP assessment during volume assist control ventilation at a usual constant-flow rate of 60 L/min.

Objectives: To validate the conductive pressure (P) method, which compare the P-defined on the airway pressure waveform as the difference between the airway pressure level at which an abrupt change in slope occurs at the beginning of insufflation and PEEP-to resistive pressure for AOP detection and measurement, and to compare its respiratory and hemodynamic tolerance to the standard low-flow insufflation method.

A new reservoir-based CPAP with low oxygen consumption: the Bag-CPAP.

Background: Several noninvasive ventilatory supports rely in their design on high oxygen consumption which may precipitate oxygen shortage, as experienced during the COVID-19 pandemic. In this bench-to-bedside study, we assessed the performance of a new continuous positive airway pressure (CPAP) device integrating a large reservoir ("Bag-CPAP") designed to minimize oxygen consumption, and compared it with other CPAP devices.

Methods: First, a bench study compared the performances of Bag-CPAP and four CPAP devices with an intensive care unit ventilator.

Is COVID-19 different from other causes of acute respiratory distress syndrome?

Coronavirus disease 2019 (COVID-19) pneumonia can lead to acute hypoxemic respiratory failure. When mechanical ventilation is needed, almost all patients with COVID-19 pneumonia meet the criteria for acute respiratory distress syndrome (ARDS). The question of the specificities of COVID-19-associated ARDS compared to other causes of ARDS is of utmost importance, as it may justify changes in ventilatory strategies.

A novel capnogram analysis to guide ventilation during cardiopulmonary resuscitation: clinical and experimental observations.

Background: Cardiopulmonary resuscitation (CPR) decreases lung volume below the functional residual capacity and can generate intrathoracic airway closure. Conversely, large insufflations can induce thoracic distension and jeopardize circulation. The capnogram (CO signal) obtained during continuous chest compressions can reflect intrathoracic airway closure, and we hypothesized here that it can also indicate thoracic distension.