Determinants and Prediction of Transport Ventilators' Oxygen Consumption.

This study investigates the determinants of oxygen consumption in transport ventilators, a critical factor for patient safety, especially during long-distance transfers and in resource-limited settings. A bench study was conducted on 4 ventilators to measure oxygen consumption under various ventilation settings. The main factor influencing oxygen consumption was the bias flow, a specific flow not contributing to patient ventilation.

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.

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.

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.

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.

Continuous positive airway pressure for respiratory support during COVID-19 pandemic: a frugal approach from bench to bedside.

Background: We describe a frugal approach (focusing on needs, performance, and costs) to manage a massive influx of COVID-19 patients with acute hypoxemic respiratory failure (AHRF) using the Boussignac valve protected by a filter ("Filter Frugal CPAP", FF-CPAP) in and out the ICU.

Methods: (1) A bench study measured the impact of two filters with different mechanical properties on CPAP performances, and pressures were also measured in patients. (2) Non-ICU healthcare staff working in COVID-19 intermediate care units were trained with a video tutorial posted on a massive open online course.

Reliability and limits of transport-ventilators to safely ventilate severe patients in special surge situations.

Background: Intensive Care Units (ICU) have sometimes been overwhelmed by the surge of COVID-19 patients. Extending ICU capacity can be limited by the lack of air and oxygen pressure sources available. Transport ventilators requiring only one O source may be used in such places.

OCT and CMR for the Diagnosis of Patients Presenting With MINOCA and Suspected Epicardial Causes.

Objectives: Among all patients presenting with myocardial infarction with nonobstructive coronary arteries (MINOCA), epicardial causes may be suspected when there is a correlation between electrocardiogram (ECG) changes and regional wall motion abnormalities (WMAs). We evaluated the diagnostic yield of intravascular optical coherence tomography (OCT) and cardiac magnetic resonance (CMR) in this specific setting.

Background: OCT is able to identify different morphologic features of coronary plaques that are well known causes of MINOCA.

Gastric insufflation during cardiopulmonary resuscitation: A study in human cadavers.

Introduction: Bag-valve-mask ventilation is the first-line ventilation method during cardiopulmonary resuscitation (CPR). Risks include excessive volume delivery and gastric insufflation, the latter increasing the risk of pneumonia. The efficacy of ventilation can also be reduced by airway closure.