Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause severe pneumonia requiring invasive mechanical ventilation [1], in the context of atypical acute respiratory distress syndrome (ARDS) [2]. The magnitude of the epidemic places an unprecedented pressure on intensive care units (ICUs), making avoidance of intubation a critical issue. Supplemental oxygen is the first-line treatment of ARDS. When escalation is needed, pre-intubation approaches carry the risk of delaying intubation and increasing mortality [3]. Noninvasive ventilation (NIV) is not recommended [4] but high-flow nasal oxygen (HFNO) may decrease the need for intubation without impacting mortality [4, 5]. Mostly because of an early negative report [6], continuous positive airway pressure (CPAP) remains largely undocumented in ARDS. In SARS-CoV-2 pneumonia, evidence-based guidelines are lacking [7] but CPAP could prove useful [8]. In this context, on 20 March, 2020, the French learned society for respiratory medicine circulated a clinical management algorithm derived from the Italian experience and suggesting the use of CPAP in SARS-CoV-2 patients requiring oxygen escalation [8]. This algorithm was implemented in our department on 24 March, 2020, in a context of limited HFNO availability and environmental contamination concerns. We designed this retrospective study to evaluate the impact of the CPAP strategy on intubation rate. We compared the period immediately before the algorithm implementation (11-23 March, 2020) with the period immediately after (24 March to 8 April), testing the hypothesis that CPAP can avoid intubation in patients with severe forms of SARS-CoV-2 pneumonia over the first week of their management. This observational study with short-term historical controls was conducted in the 25-bed pulmonology unit of a 1600-bed university hospital (Pitié-Salpêtrière, Paris, France). It was approved by the institutional review board of the French learned society for respiratory medicine (CEPRO2020-024). Patients were informed of the use of their anonymised data and given the opportunity to refuse it.

Objective The coronavirus disease pandemic (COVID-19) increased the risk of shortage in intensive care devices, including fittings with intentional leaks. 3D-printing has been used worldwide to produce missing devices. Here we provide key elements towards better quality control of 3D-printed ventilation fittings in a context of sanitary crisis. Material and methods Five 3D-printed designs were assessed for non-intentional (junctional and parietal) and intentional leaks: 4 fittings 3D-printed in-house using FDeposition Modelling (FDM), 1 FDM 3D-printed fitting provided by an independent maker, and 2 fittings 3D-printed in-house using Polyjet technology. Five industrial models were included as controls. Two values of wall thickness and the use of coating were tested for in-house FDM-printed devices. Results Industrial and Polyjet-printed fittings had no parietal and junctional leaks, and satisfactory intentional leaks. In-house FDM-printed fittings had constant parietal leaks without coating, but this post-treatment method was efficient in controlling parietal sealing, even in devices with thinner walls (0.7 mm vs 2.3 mm). Nevertheless, the use of coating systematically induced absent or insufficient intentional leaks. Junctional leaks were constant with FDM-printed fittings but could be controlled using rubber junctions rather than usual rigid junctions. The properties of Polyjet-printed and FDM-printed fittings were stable over a period of 18 months. Conclusions 3D-printing is a valid technology to produce ventilation devices but requires care in the choice of printing methods, raw materials, and post-treatment procedures. Even in a context of sanitary crisis, devices produced outside hospitals should be used only after professional quality control, with precise data available on printing protocols. The mechanical properties of ventilation devices are crucial for efficient ventilation, avoiding rebreathing of CO2, and preventing the dispersion of viral particles that can contaminate health professionals. Specific norms are still required to formalise quality control procedures for ventilation fittings, with the rise of 3D-printing initiatives and the perspective of new pandemics.

Non-invasive ventilation (NIV) is commonly used at home for patient with nocturnal hypoventilation caused by a chronic respiratory failure. Monitoring NIV is required to optimize the ventilator settings when the lung condition changes over time, and to detect common problems such as unintentional leaks, upper airway obstructions, and patient–ventilator asynchronies. This review describes the accuracy and limitations of the data recorded by the ventilator. To efficiently interpret this huge amount of data, clinician assess the daily use and regularity of NIV utilization, the unintentional leaks and their repartition along the NIV session, the apnea–hypopnea index and the flow waveform, and the patient–ventilator synchrony. Nocturnal recordings of gas exchanges are also required to detect nocturnal alveolar hypoventilation. This review describes the indication, validity criteria, and interpretation of nocturnal oximetry and transcutaneous capnography. Polygraphy and polysomnography are indicated in specific cases to characterize upper airway obstruction. Telemonitoring of the ventilator is a useful tool that should be integrated in the monitoring strategy. The technical solution, information, and limitations are discussed. In conclusion, a basic monitoring package is recommended for all patients complemented by advanced monitoring for specific cases.