BackgroundThe 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.MethodsA prospective, randomized, cross-over study was performed on 40 acute hypoxemic respiratory failure (AHRF) patients (PaO2/FiO2 ≤ 300 + pulmonary infiltrates + exclusion of cardiogenic edema) supported by HFNC. The primary outcome was the assessment of patient comfort during HFNC delivery at increasing flow and temperature. Two flows (30 and 60 l/min), each combined with two temperatures (31 and 37 °C), were randomly applied for 20 min (four steps per patient), leaving clinical FiO2 unchanged. Toward the end of each step, the following were recorded: comfort by Visual Numerical Scale ranging between 1 (extreme discomfort) and 5 (very comfortable), together with respiratory parameters. A subgroup of more severe patients was defined by clinical FiO2 ≥ 45%.ResultsPatient comfort was reported as significantly higher during steps at the lower temperature (31 °C) in comparison to 37 °C, with the HFNC set at both 30 and 60 l/min (p < 0.0001). Higher flow, however, was not associated with poorer comfort.In the subgroup of patients with clinical FiO2 ≥ 45%, both lower temperature (31 °C) and higher HFNC flow (60 l/min) led to higher comfort (p < 0.01).ConclusionsHFNC temperature seems to significantly impact the comfort of AHRF patients: for equal flow, lower temperature could be more comfortable. Higher flow does not decrease patient comfort; at variance, it improves comfort in the more severely hypoxemic patient.

Objective To determine the prevalence of complications in patients with COVID-19 undergone prone positioning, focusing on the development of prone-related pressure ulcers. Methods Cross-sectional study conducted in the hub COVID-19 center in Milan (Italy), between March and June 2020. All patients with COVID-19 admitted to intensive care unit on invasive mechanical ventilation and treated with prone positioning were included. Association between prone-related pressure ulcers and selected variables was explored by the means of logistic regression. Results A total of 219 proning cycles were performed on 63 patients, aged 57.6 (10.8) and predominantly obese males (66.7%). The main complications recorded were: prone-related pressure ulcers (30.2%), bleeding (25.4%) and medical device displacement (12.7%), even if none unplanned extubation was recorded. Bleeding of upper airways represented the most common site (17.5%). Only 15 prone positioning cycles (6.8%) were interrupted, requiring staff to roll the patient back in the supine position. The likelihood of pressure ulcers development was independently associated with the duration of prone positioning, once adjusting for age, hypoxemic level, and nutritional status (OR 1.9, 95%CI 1.04 to 3.6). Conclusion The use of prone positioning in patients with COVID-19 was a safe and feasible treatment, also in obese patients, who might deserve more surveillance and active prevention by intensive care unit staff.

BackgroundPositive end-expiratory pressure (PEEP) is a key element of mechanical ventilation. It should optimize recruitment, without causing excessive overdistension, but controversy exists on the best method to set it. The purpose of the study was to test the feasibility of setting PEEP with electrical impedance tomography in order to prevent lung de-recruitment following a recruitment maneuver. We enrolled 16 patients undergoing mechanical ventilation with PaO2/FiO2 <300 mmHg. In all patients, under constant tidal volume (6–8 ml/kg) PEEP was set based on the PEEP/FiO2 table proposed by the ARDS network (PEEPARDSnet). We performed a recruitment maneuver and monitored the end-expiratory lung impedance (EELI) over 10 min. If the EELI signal decreased during this period, the recruitment maneuver was repeated and PEEP increased by 2 cmH2O. This procedure was repeated until the EELI maintained a stability over time (PEEPEIT).ResultsThe procedure was feasible in 87% patients. PEEPEIT was higher than PEEPARDSnet (13 ± 3 vs. 9 ± 2 cmH2O, p < 0.001). PaO2/FiO2 improved during PEEPEIT and driving pressure decreased. Recruited volume correlated with the decrease in driving pressure but not with oxygenation improvement. Finally, regional alveolar hyperdistention and collapse was reduced in dependent lung layers and increased in non-dependent lung layers.ConclusionsIn hypoxemic patients, a PEEP selection strategy aimed at stabilizing alveolar recruitment guided by EIT at the bedside was feasible and safe. This strategy led, in comparison with the ARDSnet table, to higher PEEP, improved oxygenation and reduced driving pressure, allowing to estimate the relative weight of overdistension and recruitment.Electronic supplementary materialThe online version of this article (doi:10.1186/s13613-017-0299-9) contains supplementary material, which is available to authorized users.

Background At the height of the coronavirus disease 2019 (COVID-19) pandemic, Italy had the highest number of deaths in Europe; most occurred in the Lombardy region. Up to 4% of patients with COVID-19 required admission to an intensive care unit because they developed a critical illness (eg, acute respiratory distress syndrome). Numerous patients with acute respiratory distress syndrome who had been admitted to the intensive care unit required rescue therapy like prone positioning. Objectives To describe the respiratory management of and the extensive use of prone positioning in patients with COVID-19 at the intensive care unit hub in Lombardy, Italy. Methods A total of 89 patients (67% male; median age, 59 years [range, 23-80 years]) with confirmed COVID-19 who were admitted between February 23 and March 31, 2020, were enrolled in this quality improvement project. Results Endotracheal intubation was required in 86 patients (97%). Prone positioning was used as rescue therapy in 43 (48%) patients. Significantly more younger patients (age ≤ 59 years) were discharged alive (43 of 48 [90%]) than were older patients (age ≥ 60 years; 26 of 41 [63%]; P &lt; .005). Among the 43 patients treated with prone ventilation, 15 (35% [95% CI, 21%-51%]) died in the intensive care unit, of which 10 (67%; P &lt; .001) were older patients. Conclusions Prone positioning is one strategy available for treating acute respiratory distress syndrome in patients with COVID-19. During this pandemic, prone positioning can be used extensively as rescue therapy, per a specific protocol, in intensive care units.

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