[High-flow nasal oxygen therapy and hypercapnic acute respiratory failure]. / Oxygénothérapie nasale à haut débit et insuffisance respiratoire aiguë hypercapnique.

Humidified high-flow nasal oxygen therapy (HFNO) has, in recent years, come to assume a key role in the management of hypoxemic acute respiratory failure (ARF). While non-invasive ventilation (NIV) currently represents the first-line ventilatory strategy in patients exhibiting hypercapnic ARF, the operating principles and physiological effects of HFNO could be interesting and useful in the initial management of hypercapnic ARF and/or after extubation, particularly in acute exacerbations of chronic obstructive pulmonary disease. Under these conditions, HFNO could be used either alone continuously or in combination with NIV during breaks in spontaneous breathing, depending on the severity and etiology of the underlying hypercapnic ARF.

[Operating principles, physiological effects and practical issues of high-flow nasal oxygen therapy]. / Principes de fonctionnement, effets physiologiques et aspects pratiques de l'oxygénothérapie à haut débit.

First-line symptomatic treatment of acute respiratory failure (ARF) usually requires standard oxygen therapy, of which the limits have nonetheless led to the development of heated and humidified high-flow nasal oxygen therapy (HFNO). HFNO enables the delivery, through simple nasal cannula, of up to 100% of well-heated and humidified fraction of inspired oxygen (FiO2), at a maximum flow rate of 50 to 70 L/min of gas according to the devices chosen (specific or ventilator). The technical characteristics and operating principles of HFNO (coverage of the patient's spontaneous inspiratory flow, improved conditioning of the inspired gases, comfortable nasal cannula) yield a number of interdependent physiological effects that improve not only oxygenation conditions but also ventilatory mechanics. While it could be indicated in many clinical situations, including first-line hypoxemic ARF, the simplicity of HFNO implementation and the respiratory comfort it procures should in no way minimize the clinical monitoring of patients for whom endotracheal intubation may be required, and should not be unduly delayed.

Covid-19 severe hypoxemic pneumonia: A clinical experience using high-flow nasal oxygen therapy as first-line management.

PURPOSE: To report a French experience in patients admitted to Intensive Care Unit (ICU) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requiring high fractional concentration of inspired oxygen supported by high flow nasal cannula (HFNC) as first-line therapy. METHODS: Retrospective cohort study conducted in two ICUs of a French university hospital. All consecutive patients admitted during 28-days after the first admission for SARS-CoV-2 pneumonia were screened. Demographic, clinical, respiratory support, specific therapeutics, ICU length-of-stay and survival data were collected. RESULTS: Data of 43 patients were analyzed: mainly men (72%), median age 61 (51-69) years, median body mass index of 28 (25-31) kg/m2, median simplified acute physiology score (SAPS II) of 29 (22-37) and median PaO2/fraction of inspired oxygen (FiO2) (P/F) ratio of 146 (100-189) mmHg. HFNC was initiated at ICU admission in 76% of patients. Median flow was 50 (45-50) L/min and median FiO2 was 0.6 (0.5-0.8). 79% of patients presented at least one comorbidity, mainly hypertension (58%). At day (D) 28, 32% of patients required invasive mechanical ventilation, 3 patients died in ICU. Risk factors for intubation were diabetes (10% vs. 43%, P=0.04) and extensive lesions on chest computed tomography (CT) (P=0.023). Patients with more than 25% of lesions on chest CT were more frequently intubated during ICU stay (P=0.012). At ICU admission (D1), patients with higher SAPS II and Sequential Organ Failure Assessment (SOFA) scores (respectively 39 (28-50) vs. 27 (22-31), P=0.0031 and 5 (2-8) vs. 2 (2-2.2), P=0.0019), and a lower P/F ratio (98 (63-109) vs. 178 (126-206), P=0.0005) were more frequently intubated. Among non-intubated patients, the median lowest P/F was 131 (85-180) mmHg. Four caregivers had to stop working following coronavirus 2 contamination, but did not require hospitalization. CONCLUSION: Our clinical experience supports the use of HFNC as first line-therapy in patients with SARS-COV-2 pneumonia for whom face mask oxygen does not provide adequate respiratory support.

Persistent swallowing disorders after extubation in mechanically ventilated patients in ICU: a two-center prospective study.

BACKGROUND: Persistent swallowing disorders (SD) are non-pulmonary complications of mechanical ventilation (MV). However, there are few clinical studies on persistent SD in critically ill patients undergoing tracheal intubation for MV. The aim of the present study was to assess the incidence and characteristics of clinical manifestations associated with persistent SD. METHODS: We prospectively evaluated in patients requiring more than 7 days of invasive MV the incidence and characteristics of clinical manifestations related to persistent SD. For this purpose, quality of swallowing was assessed within 24 h after extubation by an experienced physical therapist not directly involved in patient management. Swallowing assessment consisted in a specific standardized test combining a swallowing test and a full clinical evaluation of the cranial nerves involved in swallowing. In patients with SD on the first test, a second test was done within 48 h in order to discriminate between transient and persistent SD. RESULTS: Among the 482 patients mechanically ventilated more than 7 days, 138 were enrolled in this study. The first test performed 24 h after extubation revealed SD in 35 patients (25%). According to the second test performed 48 h later, SD were considered transient in 21 (15%) and persistent in 14 (10%) cases. Patients with persistent SD were older (66 ± 16 vs 58 ± 15 years), had lower bodyweight at admission (76 ± 15 vs 87 ± 23 kg) and received less often neuromuscular blocking agents (36% vs 66%) compared to patients without or with only transient SD. Patients with persistent SD had longer duration of Intensive Care Unit (ICU) stay after first extubation and longer delay to oral feeding than patients without or with only transient SD, respectively, 11 ± 9 vs 7 ± 6 days and 23 ± 33 vs 5 ± 7 days. CONCLUSIONS: Based on a specific standardized clinical test, 25% of patients mechanically ventilated more than 7 days exhibited clinical manifestations of SD. However, SD were considered as persistent after extubation in only 10% of them. Persistent SD were associated with longer duration of ICU stay after extubation and longer time of enteral feeding. TRIAL REGISTRATION: The study is registered with Clinical Trials (NCT01360580).

Feasibility and safety of ultra-low tidal volume ventilation without extracorporeal circulation in moderately severe and severe ARDS patients.

PURPOSE: Mechanical ventilation with ultra-low tidal volume (VT) during ARDS may reduce alveolar strain, driving pressure and hence ventilator-induced lung injury, with the main drawback of worsening respiratory acidosis. We hypothesized that VT could be reduced down to 4 ml/kg, with clinically significant decrease in driving pressure, without the need for extracorporeal CO2 removal, while maintaining pH > 7.20. METHODS: We conducted a non-experimental before-and-after multicenter study on 35 ARDS patients with PaO2/FiO2 ≤ 150 mmHg, within 24 h of ARDS diagnosis. After inclusion, VT was reduced to 4 ml/kg and further adjusted to maintain pH ≥ 7.20, respiratory rate was increased up to 40 min-1 and PEEP was set using a PEEP-FiO2 table. The primary judgment criterion was driving pressure on day 2 of the study, as compared to inclusion. RESULTS: From inclusion to day 2, driving pressure decreased significantly from 12 [9-15]  to 8 [6-11] cmH2O, while VT decreased from 6.0 [5.9-6.1] to 4.1 [4.0-4.7] ml/kg. On day 2, VT was below 4.2 ml/kg in 65% [CI95% 48%-79%], and below 5.25 ml/kg in 88% [CI95% 74%-95%] of the patients. 2 patients (6%) developed acute cor pulmonale after inclusion. Eleven patients (32%) developed transient severe acidosis with pH < 7.15. Fourteen patients (41%) died before day 90. CONCLUSION: Ultra-low tidal volume ventilation may be applied in approximately 2/3 of moderately severe-to-severe ARDS patients, with a 4 cmH2O median reduction in driving pressure, at the price of transient episodes of severe acidosis in approximately 1/3 of the patients.

Effect of different seated positions on lung volume and oxygenation in acute respiratory distress syndrome.

RATIONALE: Lung volume available for ventilation is markedly decreased during acute respiratory distress syndrome. Body positioning may contribute to increase lung volume and partial verticalization is simple to perform. This study evaluated whether verticalization had parallel effects on oxygenation and end expiratory lung volume (EELV). METHODS: Prospective multicenter study in 40 mechanically ventilated patients with ALI/ARDS in five university hospital MICUs. We evaluated four 45-min successive trunk position epochs (supine slightly elevated at 15°; semi recumbent with trunk elevated at 45°; seated with trunk elevated at 60° and legs down at 45°; back to supine). Arterial blood gases, EELV measured using the nitrogen washin/washout, and static compliance were measured. Responders were defined by a PaO2/FiO2 increase >20 % between supine and seated position. Results are median [25th-75th percentiles]. RESULTS: With median PEEP = 10 cmH2O, verticalization increased lung volume but only responders (13 patients, 32 %) had a significant increase in EELV/PBW (predicted body weight) compared to baseline. This increase persisted at least partially when patients were positioned back to supine. Responders had a lower EELV/PBW supine [14 mL/kg (13-15) vs. 18 mL/kg (15-27) (p = 0.005)] and a lower compliance [30 mL/cmH2O (22-38) vs. 42 (30-46) (p = 0.01)] than non-responders. Strain decreased with verticalization for responders. EELV/PBW increase and PaO2/FiO2 increase were not correlated. DISCUSSION: Verticalization is easily achieved and improves oxygenation in approximately 32 % of the patients together with an increase in EELV. Nonetheless, effect of verticalization on EELV/PBW is not predictable by PaO2/FiO2 increase, its monitoring may be helpful for strain optimization.

PEEP-induced changes in lung volume in acute respiratory distress syndrome. Two methods to estimate alveolar recruitment.

PURPOSE: Lung volumes, especially functional residual capacity (FRC), are decreased in acute respiratory distress syndrome (ARDS). Positive end-expiratory pressure (PEEP) contributes to increased end-expiratory lung volume (EELV) and to improved oxygenation, but differentiating recruitment of previously nonaerated lung units from distension of previously open lung units remains difficult. This study evaluated simple methods derived from bedside EELV measurements to assess PEEP-induced lung recruitment while monitoring strain. METHODS: Prospective multicenter study in 30 mechanically ventilated patients with ARDS in five university hospital ICUs. Two PEEP levels were studied, each for 45 min, and EELV (nitrogen washout/washin technique) was measured at both levels, with the difference (Δ) reflecting PEEP-induced lung volume changes. Alveolar recruitment was measured using pressure-volume (PV) curves. High and low recruiters were separated based on median recruitment at high PEEP. Minimum predicted increase in lung volume computed as the product of ΔPEEP by static compliance was subtracted from ΔEELV as an independent estimate of recruitment. Estimated and measured recruitments were compared. Strain induced by PEEP was also calculated from the same measurements. RESULTS: FRC was 31 ± 11% of predicted. Median [25th-75th percentiles] PEEP-induced recruitment was 272 [187-355] mL. Estimated recruitment correlated with recruited volume measured on PV curves (ρ = 0.68), with a slope close to identity. The ΔEELV/FRC ratio differentiated high from low recruiters (110 [76-135] vs. 55 [23-70]%, p = 0.001). Strain increase due to PEEP was larger in high recruiters (p = 0.002). CONCLUSION: PEEP-induced recruitment and strain can be assessed at the bedside using EELV measurement. We describe two bedside methods for predicting low or high alveolar recruitment during ARDS.

[Quality of care assessment and nosocomial pneumonia in the intensive care unit]. / Evaluation des soins et pneumopathies nosocomiales en réanimation.

INTRODUCTION: Nosocomial pneumonia (NP) is a major cause of infection in the intensive care unit and is responsible for a significant increase in morbidity, mortality and healthcare costs. Ventilator-associated pneumonia is the most frequent and severe form of NP. STATE OF ART: Assessment of the quality of care and healthcare practices relating to the prevention and treatment of nosocomial pneumonia represents a potentially vast area but has been little studied in the literature. Difficulties include the lack of either a "gold standard" for diagnosis, or standardization of techniques for microbiological sampling and, therefore, the lack of reliable indicators of performance in the management of NP. Currently, published data mainly involve diagnostic strategies, preventive measures and antibiotic therapy. PERSPECTIVES AND CONCLUSIONS: In line with the latest published recommendations, clinicians should continue their efforts in this field to improve the management and reduce the impact of NP in the intensive care unit.

[Mediastinal teratoma with recurrent encysted pleural effusion]. / Tératome médiastinal avec épanchement pleural enkysté récidivant.

A 25 year old man with no previous history was admitted for a recurrent right sided encysted pleural effusion. Thoracocentesis revealed an exudative lipase-rich-fluid. Because of the persistence of abundant pleural fluid after several thoracocentesis a diagnostic mediastinotomy was performed. This revealed a necrotic cystic mediastinal tumor composed of well differentiated pancreatic tissue, nervous tissue, digestive and respiratory glands, and a dermoid mass with hair and sebacious glands. This led to a diagnosis of benign, mature mediastinal teratoma. We suggest that the chronic pleural effusion was maintained by a fistula from the tumour into the pleural cavity and the secretion of proteolytic enzymes by the well-differentiated pancreatic tissue.

[Endobronchial localization of Launois Bensaude syndrome]. / Localisation endobronchique d'un syndrome de Launois-Bensaude.

Launois Bensaude syndrome is a benign, asymetric lipomatosis involving the upper back, shoulders, neck and arms. The disorder is usually asymptomatic although mediastinal lipomas, extrinsic compression of trachea, obstructive sleep apnea syndrome have been described. We report for the first time to our knowledge a case of Launois Bensaude syndrome with bronchial submucosal adiposis infiltration presenting as flask, smooth, begnin tumor like formation involving several bronchi. Whether this submucosal adipose infiltration participate to the obstructive syndrome is discussed.

[Radiological evidence of lung involvement in metal fume fever]. / Atteinte pulmonaire radiologique au cours d'une fièvre des métaux.

We report the case of a 32-year-old welder who developed a flu-like syndrome a few hours after founding zinc. The patient experienced fever, headache, muscle pain and dyspnea that resolved spontaneously with a few hours. The diagnosis of metal fume fever was retained. The chest x-ray evidenced bilateral diffuse infiltrative pulmonary lesions, rarely described in this syndrome. Metal fume fever is a likely diagnosis in exposed patients who develop fever with diffuse lung involvement.