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. This study aimed to comprehensively assess respiratory mechanics in obese and non-obese ICU patients with or without ARDS and evaluate the contribution of advanced respiratory mechanics assessments compared to basic assessments in these patients. METHODS: All intubated patients admitted in two ICUs for any cause were prospectively included. Gas exchange and respiratory mechanics including esophageal pressure and end-expiratory lung volume (EELV) measurements and low-flow insufflation to detect complete airway closure were assessed in standardized conditions (tidal volume of 6 mL kg-1 predicted body weight (PBW), positive end-expiratory pressure (PEEP) of 5 cmH2O) within 24 h after intubation. RESULTS: Among the 149 analyzed patients, 52 (34.9%) were obese and 90 (60.4%) had ARDS (65.4% and 57.8% of obese and non-obese patients, respectively, p = 0.385). A complete airway closure was found in 23.5% of the patients. It was more frequent in obese than in non-obese patients (40.4% vs 14.4%, p < 0.001) and in ARDS than in non-ARDS patients (30% vs. 13.6%, p = 0.029). Respiratory system and lung compliances and EELV/PBW were similarly decreased in obese patients without ARDS and obese or non-obese patients with ARDS. Chest wall compliance was not impacted by obesity or ARDS, but end-expiratory esophageal pressure was higher in obese than in non-obese patients. Chest wall contribution to respiratory system compliance differed widely between patients but was not predictable by their general characteristics. CONCLUSIONS: Most respiratory mechanics features are similar in obese non-ARDS and non-obese ARDS patients, but end-expiratory esophageal pressure is higher in obese patients. A complete airway closure can be found in around 25% of critically ill patients ventilated with a PEEP of 5 cmH2O. Advanced explorations may allow to better characterize individual respiratory mechanics and adjust ventilation strategies in some patients. Trial registration NCT03420417 ClinicalTrials.gov (February 5, 2018).

The Sequential Organ Failure Assessment (SOFA) Score: has the time come for an update?

The Sequential Organ Failure Assessment (SOFA) score was developed more than 25 years ago to provide a simple method of assessing and monitoring organ dysfunction in critically ill patients. Changes in clinical practice over the last few decades, with new interventions and a greater focus on non-invasive monitoring systems, mean it is time to update the SOFA score. As a first step in this process, we propose some possible new variables that could be included in a SOFA 2.0. By so doing, we hope to stimulate debate and discussion to move toward a new, properly validated score that will be fit for modern practice.

Frailty assessment for COVID-19 follow-up: a prospective cohort study.

BACKGROUND: The Clinical Frailty Scale (CFS) is increasingly used for clinical decision making in acute care but little is known about frailty after COVID-19. OBJECTIVES: To investigate frailty and the CFS for post-COVID-19 follow-up. METHODS: This prospective multicentre cohort study included COVID-19 survivors aged ≥50 years presenting for a follow-up visit ≥3 months after the acute illness. Nine centres retrospectively collected pre-COVID-19 CFS and prospectively CFS at follow-up. Three centres completed the Frailty Index (FI), the short physical performance battery (SPPB), 30 s sit-to-stand test and handgrip strength measurements. Mixed effect logistic regression models accounting for repeated measurements and potential confounders were used to investigate factors associated with post-COVID-19 CFS. Criterion and construct validity were determined by correlating the CFS to other concurrently assessed frailty measurements and measures of respiratory impairment, respectively. RESULTS: Of the 288 participants 65% were men, mean (SD) age was 65.1 (9) years. Median (IQR) CFS at follow-up was 3 (2-3), 21% were vulnerable or frail (CFS ≥4). The CFS was responsive to change, correlated with the FI (r=0.69, p<0.001), the SPPB score (r=-0.48, p<0.001) (criterion validity) and with the St George's Respiratory Questionnaire score (r=0.59, p<0.001), forced vital capacity %-predicted (r=-0.25, p<0.001), 6 min walk distance (r=-0.39, p<0.001) and modified Medical Research Council (mMRC) (r=0.59, p<0.001). Dyspnoea was significantly associated with a higher odds for vulnerability/frailty (per one mMRC adjusted OR 2.01 (95% CI 1.13 to 3.58), p=0.02). CONCLUSIONS: The CFS significantly increases with COVID-19, and dyspnoea is an important risk factor for post-COVID-19 frailty and should be addressed thoroughly.

Assessment of a massive open online course (MOOC) incorporating interactive simulation videos on residents' knowledge retention regarding mechanical ventilation.

BACKGROUND: Understanding respiratory physiology and mechanical ventilation is a challenge for healthcare workers, particularly, medical residents. A team of French-speaking experts developed an innovative MOOC incorporating interactive simulation-based videos and serious games aiming at improving knowledge and skills in mechanical ventilation. Our objective was to evaluate the long-term knowledge retention regarding key concepts presented in this MOOC. METHODS: French residents registered for the MOOC 2020's winter session were invited to participate in a two-step study. The first step consisted in evaluating students' pre-course knowledge of respiratory physiology and mechanical ventilation fusing a 20 five-item multiple choice questions test with a total score ranging from 0 to 100. For the second step, the same students answered the same test (after shuffling the questions) six months after the completion of the course. We assessed the impact of this MOOC on the students' knowledge retention by comparing pre-course and post-course scores. RESULT: Of the 102 residents who agreed to participate in the study, 80 completed the course and their mean ± SD pre-course score was 76.0 ± 8.0. Fifty-one respondents also completed the second and their post-course score was significantly higher than the baseline one (83.1 ± 7.3 vs. 77.5 ± 7.6, p < 0.001). Scores of the first and second rounds did not differ upon comparing respondents' background specialty or number of years of residency. For the vast majority of individual questions (96%), the success rate was higher at the post-course than at the pre-course assessment. CONCLUSION: An innovative MOOC incorporating simulation-based videos was effective in teaching medical residents basic mechanical ventilation knowledge and skills, especially in the field of respiratory physiology and ventilatory modes. We observed effective long-term knowledge retention with a higher score at the post-course assessment six months after the completion of the course compared with the pre-course score.

Assessment of renal hemodynamic toxicity of fluid challenge with 0.9% NaCl compared to balanced crystalloid (PlasmaLyte®) in a rat model with severe sepsis.

BACKGROUND: According to international guidelines, volume expansion with crystalloids is the first-line treatment for hemodynamic management in patients with severe sepsis or septic shock. Compared to balanced crystalloids, 0.9% sodium chloride (0.9% NaCl) induces hyperchloremia and metabolic acidosis and may alter renal hemodynamics and function. We compared the effects of 0.9% NaCl to a less chloride-concentrated fluid, PlasmaLyte® (PL) in targeted fluid resuscitation in a randomized, double-blind controlled study in an experimental model of severe sepsis in rats. RESULTS: A sepsis with hypotension was induced by cecal ligature and puncture (CLP) in 40 male Wistar rats (20 for each crystalloid). Rats received fluid resuscitation over a period of 200 min for a targeted mean arterial pressure of 90 mm Hg. Animals received similar volumes of 0.9% NaCl or PL. Unlike PL-resuscitated rats, 0.9% NaCl-resuscitated rats experienced hyperchloremia and metabolic acidosis, whereas systemic hemodynamics, renal hemodynamics and renal function were not significantly different between both groups. CONCLUSION: In our model of rats with severe sepsis resuscitated with large amounts of crystalloids, 0.9% NaCl-induced hyperchloremic acidosis, but balanced crystalloid did not improve systemic and renal hemodynamics or renal function.

Geo-economic variations in epidemiology, patterns of care, and outcomes in patients with acute respiratory distress syndrome: insights from the LUNG SAFE prospective cohort study.

BACKGROUND: Little information is available about the geo-economic variations in demographics, management, and outcomes of patients with acute respiratory distress syndrome (ARDS). We aimed to characterise the effect of these geo-economic variations in patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE). METHODS: LUNG SAFE was done during 4 consecutive weeks in winter, 2014, in a convenience sample of 459 intensive-care units in 50 countries across six continents. Inclusion criteria were admission to a participating intensive-care unit (including transfers) within the enrolment window and receipt of invasive or non-invasive ventilation. One of the trial's secondary aims was to characterise variations in the demographics, management, and outcome of patients with ARDS. We used the 2016 World Bank countries classification to define three major geo-economic groupings, namely European high-income countries (Europe-High), high-income countries in the rest of the world (rWORLD-High), and middle-income countries (Middle). We compared patient outcomes across these three groupings. LUNG SAFE is registered with ClinicalTrials.gov, number NCT02010073. FINDINGS: Of the 2813 patients enrolled in LUNG SAFE who fulfilled ARDS criteria on day 1 or 2, 1521 (54%) were recruited from Europe-High, 746 (27%) from rWORLD-High, and 546 (19%) from Middle countries. We noted significant geographical variations in demographics, risk factors for ARDS, and comorbid diseases. The proportion of patients with severe ARDS or with ratios of the partial pressure of arterial oxygen (PaO2) to the fractional concentration of oxygen in inspired air (FiO2) less than 150 was significantly lower in rWORLD-High countries than in the two other regions. Use of prone positioning and neuromuscular blockade was significantly more common in Europe-High countries than in the other two regions. Adjusted duration of invasive mechanical ventilation and length of stay in the intensive-care unit were significantly shorter in patients in rWORLD-High countries than in Europe-High or Middle countries. High gross national income per person was associated with increased survival in ARDS; hospital survival was significantly lower in Middle countries than in Europe-High or rWORLD-High countries. INTERPRETATION: Important geo-economic differences exist in the severity, clinician recognition, and management of ARDS, and in patients' outcomes. Income per person and outcomes in ARDS are independently associated. FUNDING: European Society of Intensive Care Medicine, St Michael's Hospital, University of Milan-Bicocca.

Neonatal and adult ICU ventilators to provide ventilation in neonates, infants, and children: a bench model study.

BACKGROUND: Using a bench test model, we investigated the hypothesis that neonatal and/or adult ventilators equipped with neonatal/pediatric modes currently do not reliably administer pressure support (PS) in neonatal or pediatric patient groups in either the absence or presence of air leaks. METHODS: PS was evaluated in 4 neonatal and 6 adult ventilators using a bench model to evaluate triggering, pressurization, and cycling in both the absence and presence of leaks. Delivered tidal volumes were also assessed. Three patients were simulated: a preterm infant (resistance 100 cm H2O/L/s, compliance 2 mL/cm H2O, inspiratory time of the patient [TI] 400 ms, inspiratory effort 1 and 2 cm H2O), a full-term infant (resistance 50 cm H2O/L/s, compliance 5 mL/cm H2O, TI 500 ms, inspiratory effort 2 and 4 cm H2O), and a child (resistance 30 cm H2O/L/s, compliance 10 mL/cm H2O, TI 600 ms, inspiratory effort 5 and 10 cm H2O). Two PS levels were tested (10 and 15 cm H2O) with and without leaks and with and without the leak compensation algorithm activated. RESULTS: Without leaks, only 2 neonatal ventilators and one adult ventilator had trigger delays under a given predefined acceptable limit (1/8 TI). Pressurization showed high variability between ventilators. Most ventilators showed TI in excess high enough to seriously impair patient-ventilator synchronization (> 50% of the TI of the subject). In some ventilators, leaks led to autotriggering and impairment of ventilation performance, but the influence of leaks was generally lower in neonatal ventilators. When a noninvasive ventilation algorithm was available, this was partially corrected. In general, tidal volume was calculated too low by the ventilators in the presence of leaks; the noninvasive ventilation algorithm was able to correct this difference in only 2 adult ventilators. CONCLUSIONS: No ventilator performed equally well under all tested conditions for all explored parameters. However, neonatal ventilators tended to perform better in the presence of leaks. These findings emphasize the need to improve algorithms for assisted ventilation modes to better deal with situations of high airway resistance, low pulmonary compliance, and the presence of leaks.