Epidemiology and outcome of acute lung injury in European intensive care units

Objectives To re-examine the epidemiology of acute lung injury (ALI) in European intensive care units (ICUs).Design and setting A 2-month inception cohort study in 78 ICUs of 10 European countries.Patients All patients admitted for more than 4 h were screened for ALI and followed up to 2 months.Measurements and main results Acute lung injury occurred in 463 (7.1%) of 6,522 admissions and 16.1% of all mechanically ventilated patients; 65.4% cases occurred on ICU admission. Among 136 patients initially presenting with mild ALI (200< PaO₂/FiO₂ 300), 74 (55%) evolved to acute respiratory distress syndrome (ARDS) within 3 days. Sixty-two patients (13.4%) remained with mild ALI and 401 had ARDS. The crude ICU and hospital mortalities were 22.6% and 32.7% (p<0.001), and 49.4% and 57.9% (p=0.0005), respectively, for mild ALI and ARDS. ARDS patients initially received a mean tidal volume of 8.3±1.9 ml/kg and a mean PEEP of 7.7±3.6 cmH₂O; air leaks occurred in 15.9%. After multivariate analysis, mortality was associated with age (odds ratio (OR) =1.2 per 10 years; 95% confidence interval (CI): 1.05–1.36), immuno-incompetence (OR: 2.88; Cl: 1.57–5.28), the severity scores SAPS II (OR: 1.16 per 10% expected mortality; Cl: 1.02–1.31) and logistic organ dysfunction (OR: 1.25 per point; Cl: 1.13–1.37), a pH less than 7.30 (OR: 1.88; Cl: 1.11–3.18) and early air leak (OR: 3.16; Cl: 1.59–6.28).Conclusions Acute lung injury was frequent in our sample of European ICUs (7.1%); one third of patients presented with mild ALI, but more than half rapidly evolved to ARDS. While the mortality of ARDS remains high, that of mild ALI is twice as low, confirming the grading of severity between the two forms of the syndrome.Electronic Supplementary Material Supplementary material is available in the online version of this article at     

Late steroid therapy in primary acute lung injury

Objective: To investigate the effect of steroid treatment in the late phase of primary acute lung injury (ALI) with special emphasis on pneumococcal pneumonia. Design: Retrospective study. Setting: Multidisciplinary intensive care unit (ICU) in a university hospital. Patients: Of 31 patients with primary ALI requiring mechanical ventilation for more than 10 days, 16 were treated with methylprednisolone and 15 served as controls. Measurements and results: Steroid and control groups were comparable regarding demographic data, APACHE II score, Multiple Organ Dysfunction Score (MODS), and PaO₂/FiO₂-ratio on admission to ICU. The mean start of steroid therapy was 9.7 days after establishment of respiratory failure, and values for control patients were registered on day 10. The PaO₂/FiO₂ ratio improved significantly within 3 days after the start of steroid therapy, and MODS and C-reactive protein decreased concurrently. No differences in mortality, in length of ICU stay, or in length of mechanical ventilation were detectable. In a subgroup analysis, for patients with Streptococcus pneumoniae pneumonia, beneficial change in physiological variables was evident. Conclusions: In patients with primary ALI, steroid therapy, started 10 days after the start of mechanical ventilation, improves gas exchange and is associated with a decrease in multiorgan dysfunction. Received: 21 July 1999 Final revision received: 1 November 1999 Accepted: 15 December 1999     

Cytokeratin 19 fragments in patients with acute lung injury: a preliminary observation

Objective Cytokeratin 19 (CK19) is a specific cytoskeletal structure for alveolar epithelium. We hypothesized that the levels of CK19 fragments in bronchoalveolar lavage (BAL) fluid could serve as an index of epithelial injury and as a prognosis marker in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). The aims of our study were, in patients with ALI/ARDS: (1) to measure CK19 fragments concentrations in BAL fluid, (2) to assess its prognostic value, and (3) to identify the cellular source of CK19 in the alveolar space.Design Prospective preliminary study.Setting University hospital surgical ICU.Patients Twenty-two mechanically ventilated patients with ALI/ARDS and 10 non-ventilated control patients. Plasma samples were obtained for 11 ALI/ARDS patients.Measurements and results The concentration of BAL CK19 fragments was higher in patients (median 4916 pg/ml, 25th–75th percentile 2717–10533) than in controls (2208 pg/ml. 767–3923; p = 0.05), and higher in 10 non-survivors (7051 pg/ml, 4372–13371) than in 12 survivors (2888 pg/ml, 1315–5639; p = 0.03 among ALI/ARDS patients). BAL CK19 fragment concentration did not correlate with simplified acute physiologic score, lung injury score or PaO₂/FIO₂ ratio, but correlated positively with BAL albumin concentration (p = 0.002) and with number of BAL macrophages (p = 0.0001). Plasma CK19 fragment concentrations were 10 times lower than those in BAL. Immunohistochemical staining for CK19 showed a strong labelling of injured detached epithelial cells and hyperplastic epithelium in ALI/ARDS lung samples.Conclusion CK19 fragment concentrations were found to be elevated in BAL fluid in ALI/ARDS patients compared with control subjects. High BAL CK19 fragment levels were associated with a poor prognosis.Electronic supplementary material The electronic reference of this article is . The online full-text version of this article includes electronic supplementary material. This material is available to authorised users and can be accessed by means of the ESM button beneath the abstract or in the structured full-text article. To cite or link to this article you can use the above reference.     

Current definitions of acute lung injury and the acute respiratory distress syndrome do not reflect their true severity and outcome

Background: Despite intensive research, there are no universally accepted clinical definitions for acute lung injury (ALI) or the acute respiratory distress syndrome (ARDS). A recent joint American-European Consensus Conference on ARDS formally defined the difference between ALI and ARDS based on the degree of oxygenation impairment. However, this definition may not reflect the true prevalence, severity and prognosis of these syndromes. Methods: During a 22-month period, 56 consecutive mechanically ventilated patients who met the American-European Consensus definition for ARDS [arterial oxygen tension/fractional inspired oxygen (PaO₂/FIO₂≤ 200 mmHg regardless of the level of positive end-expiratory pressure (PEEP), bilateral pulmonary infiltrates, and no evidence of left heart failure] were admitted into the intensive care units (ICU) of the Hospital del Pino, Las Palmas, Spain, and prospectively studied. The diagnosis of ALI and ARDS was made by a PEEP-FIO₂ trial, 24 h after patients met the Consensus inclusion criteria. Patients were classified as having ALI_{–24 h} if the PaO₂/FIO₂ was > 150 mmHg with PEEP = 5 cmH₂O, and ARDS_{–24 h} if the PaO₂ /FIO₂ was ≤ 150 mmHg with PEEP ≥ 5 cmH₂O. Results: Overall mortality was 43 % (24 of 56). However, 24 h after inclusion, PaO₂ response to PEEP 5 cmH₂O allowed the separation of our patients into two different groups: 31 patients met our ALI_{–24 h} criteria (PaO₂/FIO₂ > 150 mmHg) and their mortality was 22.6 %; 25 patients met our ARDS_{–24 h} criteria (PaO₂/FIO₂≤ 150 mmHg) and their mortality was 68 % (p = 0.0016). The differences in the respiratory severity index during the first 24 h of inclusion, PaO₂/FIO₂ ratio at baseline and at 24 h, maximum plateau airway pressure, maximum level of PEEP, and number of organ system failures during the ICU stay were statistically significant. Conclusions: Since the use of PEEP in the American-European Consensus criteria for ARDS is not mandatory, that definition does not reflect the true severity of lung damage and outcome. Our data support the need for guidelines based on a specific method of evaluating oxygenation status before the American-European Consensus definition is adopted. Received: 18 April 1999 Final revision received: 30 June 1999 Accepted: 9 July 1999     

Transpulmonary pressure measurements and lung mechanics in patients with early ARDS and SARS-CoV-2

PurposeAcute Respiratory Distress Syndrome (ARDS) secondary to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has demonstrated variable oxygenation and respiratory-system mechanics without investigation of transpulmonary and chest-wall mechanics. This study describes lung, chest wall and respiratory-system mechanics in patients with SARS-CoV-2 and ARDS.MethodsData was collected from forty patients with confirmed SARS-CoV-2 and ARDS at Beth Israel Deaconess Medical Center in Boston, Massachusetts. Esophageal balloons were placed to estimate pleural and transpulmonary pressures. Clinical characteristics, respiratory-system, transpulmonary, and chest-wall mechanics were measured over the first week.ResultsPatients had moderate-severe ARDS (PaO₂/FiO₂ 123[98–149]) and were critically ill (APACHE IV 108 [94–128] and SOFA 12 [11–13]). PaO₂/FiO₂ improved over the first week (150 mmHg [122.9–182] to 185 mmHg [138–228] (p = 0.035)). Respiratory system (30–35 ml/cm H₂O), lung (40–50 ml/cm H₂O) and chest wall (120–150 ml/cm H₂O) compliance remained similar over the first week. Elevated basal pleural pressures correlated with BMI. Patients required prolonged mechanical ventilation (14.5 days [9.5–19.0]), with a mortality of 32.5%.ConclusionsPatients displayed normal chest-wall mechanics, with increased basal pleural pressure. Respiratory system and lung mechanics were similar to known existing ARDS cohorts. The wide range of respiratory system mechanics illustrates the inherent heterogeneity that is consistent with typical ARDS.     

Relationship between D-dimers and dead-space on disease severity and mortality in COVID-19 acute respiratory distress syndrome: A retrospective observational cohort study

BackgroundDespite its diagnostic and prognostic importance, physiologic dead space fraction is not included in the current ARDS definition or severity classification. ARDS caused by COVID-19 (C-ARDS) is characterized by increased physiologic dead space fraction and hypoxemia. Our aim was to investigate the relationship between dead space indices, markers of inflammation, immunothrombosis, severity and intensive care unit (ICU) mortality.ResultsRetrospective data including demographics, gas exchange, ventilatory parameters, and respiratory mechanics in the first 24 h of invasive ventilation. Plasma concentrations of D-dimers and ferritin were not significantly different across C-ARDS severity categories. Weak relationships were found between D-dimers and VR (r = 0.07, p = 0.13), P_ETCO₂/PaCO₂ (r = −0.1, p = 0.02), or estimated dead space fraction (r = 0.019, p = 0.68). Age, PaO₂/FiO₂, pH, P_ETCO₂/PaCO₂ and ferritin, were independently associated with ICU mortality. We found no association between D-dimers or ferritin and any dead-space indices adjusting for PaO₂/FiO₂, days of ventilation, tidal volume, and respiratory system compliance.ConclusionsWe report no association between dead space and inflammatory markers in mechanically ventilated patients with C-ARDS. Our results support theories suggesting that multiple mechanisms, in addition to immunothrombosis, play a role in the pathophysiology of respiratory failure and degree of dead space in C-ARDS.     

Non-invasive ventilation for acute hypoxemic respiratory failure: intubation rate and risk factors

Introduction

We assessed rates and predictive factors of non-invasive ventilation (NIV) failure in patients admitted to the intensive care unit (ICU) for non-hypercapnic acute hypoxemic respiratory failure (AHRF).

Methods

This is an observational cohort study using data prospectively collected over a three-year period in a medical ICU of a university hospital.

Results

Among 113 patients receiving NIV for AHRF, 82 had acute respiratory distress syndrome (ARDS) and 31 had non-ARDS. Intubation rates significantly differed between ARDS and non-ARDS patients (61% versus 35%, P = 0.015) and according to clinical severity of ARDS: 31% in mild, 62% in moderate, and 84% in severe ARDS (P = 0.0016). In-ICU mortality rates were 13% in non-ARDS, and, respectively, 19%, 32% and 32% in mild, moderate and severe ARDS (P = 0.22). Among patients with moderate ARDS, NIV failure was lower among those having a PaO₂/FiO₂ >150 mmHg (45% vs. 74%, p = 0.04). NIV failure was associated with active cancer, shock, moderate/severe ARDS, lower Glasgow coma score and lower positive end-expiratory pressure level at NIV initiation. Among intubated patients, ICU mortality rate was 46% overall and did not differ according to the time to intubation.

Conclusions

With intubation rates below 35% in non-ARDS and mild ARDS, NIV stands as the first-line approach; NIV may be attempted in ARDS patients with a PaO₂/FiO₂ > 150. By contrast, 84% of severe ARDS required intubation and NIV did not appear beneficial in this subset of patients. However, the time to intubation had no influence on mortality.     

A universal definition of ARDS: the PaO2/FiO2 ratio under a standard ventilatory setting—a prospective, multicenter validation study

Purpose

The PaO₂/FiO₂ is an integral part of the assessment of patients with acute respiratory distress syndrome (ARDS). The American-European Consensus Conference definition does not mandate any standardization procedure. We hypothesized that the use of PaO₂/FiO₂ calculated under a standard ventilatory setting within 24 h of ARDS diagnosis allows a more clinically relevant ARDS classification.

Methods

We studied 452 ARDS patients enrolled prospectively in two independent, multicenter cohorts treated with protective mechanical ventilation. At the time of ARDS diagnosis, patients had a PaO₂/FiO₂ ≤ 200. In the derivation cohort (n = 170), we measured PaO₂/FiO₂ with two levels of positive end-expiratory pressure (PEEP) (≥5 and ≥10 cmH₂O) and two levels of FiO₂ (≥0.5 and 1.0) at ARDS onset and 24 h later. Dependent upon PaO₂ response, patients were reclassified into three groups: mild (PaO₂/FiO₂ > 200), moderate (PaO₂/FiO₂ 101–200), and severe (PaO₂/FiO₂ ≤ 100) ARDS. The primary outcome measure was ICU mortality. The standard ventilatory setting that reached the highest significance difference in mortality among these categories was tested in a separate cohort (n = 282).

Results

The only standard ventilatory setting that identified the three PaO₂/FiO₂ risk categories in the derivation cohort was PEEP ≥ 10 cmH₂O and FiO₂ ≥ 0.5 at 24 h after ARDS onset (p = 0.0001). Using this ventilatory setting, patients in the validation cohort were reclassified as having mild ARDS (n = 47, mortality 17 %), moderate ARDS (n = 149, mortality 40.9 %), and severe ARDS (n = 86, mortality 58.1 %) (p = 0.00001).

Conclusions

Our method for assessing PaO₂/FiO₂ greatly improved risk stratification of ARDS and could be used for enrolling appropriate ARDS patients into therapeutic clinical trials.     

Prognostic value of PaO2/FiO2, SOFA and D-dimer in elderly patients with sepsis

ObjectiveTo investigate the prognostic value for predicting mortality of partial pressure of oxygen/fraction of inspired oxygen (PaO₂/FiO₂), the Sequential Organ Failure Assessment (SOFA) score and D-dimer in elderly patients with sepsis.MethodsThis retrospective cohort study enrolled elderly patients with sepsis admitted to the intensive care unit (ICU) between January 2019 and October 2020. Patients were divided into a survival group and a non-survival group. Biomarkers, SOFA, Acute Physiology and Chronic Health Evaluation II and Glasgow Coma Scale scores were recorded within 24 h after admission to the ICU.ResultsA total of 135 elderly patients with sepsis were enrolled in the study: 89 were in the survival group and 46 were in the non-survival group at 28 days. Univariate and multivariate regression analyses demonstrated that PaO₂/FiO₂, SOFA and D-dimer were independently associated with 28-day mortality. The predictive performance for mortality of the combination of PaO₂/FiO₂, SOFA score and D-dimer (area under the receiver operating characteristic curve of 0.926) was higher than the values for the individual factors (0.761, 0.745 and 0.878, respectively).ConclusionThe combination of PaO₂/FiO₂, SOFA score and D-dimer represents a promising tool and biomarker for predicting 28-day mortality of the elderly patients with sepsis.     

The clinical usefulness of extravascular lung water and pulmonary vascular permeability index to diagnose and characterize pulmonary edema: a prospective multicenter study on the quantitative differential diagnostic definition for acute lung injury/acute respiratory distress syndrome

Introduction

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is characterized by features other than increased pulmonary vascular permeability. Pulmonary vascular permeability combined with increased extravascular lung water content has been considered a quantitative diagnostic criterion of ALI/ARDS. This prospective, multi-institutional, observational study aimed to clarify the clinical pathophysiological features of ALI/ARDS and establish its quantitative diagnostic criteria.

Methods

The extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI) were measured using the transpulmonary thermodilution method in 266 patients with PaO₂/FiO₂ ratio ≤ 300 mmHg and bilateral infiltration on chest radiography, in 23 ICUs of academic tertiary referral hospitals. Pulmonary edema was defined as EVLWI ≥ 10 ml/kg. Three experts retrospectively determined the pathophysiological features of respiratory insufficiency by considering the patients'' history, clinical presentation, chest computed tomography and radiography, echocardiography, EVLWI and brain natriuretic peptide level, and the time course of all preceding findings under systemic and respiratory therapy.

Results

Patients were divided into the following three categories on the basis of the pathophysiological diagnostic differentiation of respiratory insufficiency: ALI/ARDS, cardiogenic edema, and pleural effusion with atelectasis, which were noted in 207 patients, 26 patients, and 33 patients, respectively. EVLWI was greater in ALI/ARDS and cardiogenic edema patients than in patients with pleural effusion with atelectasis (18.5 ± 6.8, 14.4 ± 4.0, and 8.3 ± 2.1, respectively; P < 0.01). PVPI was higher in ALI/ARDS patients than in cardiogenic edema or pleural effusion with atelectasis patients (3.2 ± 1.4, 2.0 ± 0.8, and 1.6 ± 0.5; P < 0.01). In ALI/ARDS patients, EVLWI increased with increasing pulmonary vascular permeability (r = 0.729, P < 0.01) and was weakly correlated with intrathoracic blood volume (r = 0.236, P < 0.01). EVLWI was weakly correlated with the PaO₂/FiO₂ ratio in the ALI/ARDS and cardiogenic edema patients. A PVPI value of 2.6 to 2.85 provided a definitive diagnosis of ALI/ARDS (specificity, 0.90 to 0.95), and a value < 1.7 ruled out an ALI/ARDS diagnosis (specificity, 0.95).

Conclusion

PVPI may be a useful quantitative diagnostic tool for ARDS in patients with hypoxemic respiratory failure and radiographic infiltrates.

Trial registration

UMIN-CTR ID UMIN000003627     

A 12-month clinical survey of incidence and outcome of acute respiratory distress syndrome in Shanghai intensive care units

Objective To investigate incidence, causes, and outcome of acute respiratory distress syndrome (ARDS) in adult patients admitted to intensive care units (ICU) in Shanghai.Design A prospective 12-month survey during 2001–2002 of the predispositions, clinical management strategies, complications, and 90-day survival rates of patients with ARDS.Patients and setting Fifteen ICU in 12 university hospitals in Shanghai. All ICU admissions 15 years of age in the 12-month period were assessed. Patients fulfilling diagnostic criteria of ARDS, as defined by the American–European Consensus Conference, and having a continuous treatment period 24 h, were recruited.Measurements and results Of 5320 adult patients admitted to ICUs, there were 108 (2%) with ARDS. At inclusion, ARDS patients had a mean PaO₂/FiO₂ value of 111.3±40.3 mmHg and a mean acute physiology and chronic health evaluation score (APACHE II) of 17.3±8.0; 33 patients had a lung injury score >2.5. Forty-one and 67 patients had ARDS associated with diseases of pulmonary and extrapulmonary origin, respectively. The most common predisposing factors for ARDS were pneumonia (34.3%) and nonpulmonary sepsis (30.6%). The overall ICU mortality was 10.3%. In-hospital and 90-day mortalities of ARDS patients were 68.5 and 70.4%, respectively, and accounted for 13.5% of the overall ICU mortality. For ARDS patients, multiple organ dysfunction syndrome was a major risk factor associated with death (59.5%).Conclusion The high morbidity and mortality of ARDS in the ICUs in Shanghai require reassessment of respiratory and intensive care management and implementation of effective therapeutic interventions.Electronic Supplementary Material Supplementary material is available in the online version of this article at     

Acute effects of continuous rotational therapy on ventilation-perfusion inequality in lung injury

Objective: To investigate ventilation-perfusion (V_A/Q) relationships, during continuous axial rotation and in the supine position, in patients with acute lung injury (ALI) using the multiple inert gas elimination technique. Design: Prospective investigation. Setting: Eighteen-bed intensive care unit in a university hospital. Patients and interventions: Ten patients with ALI (PaO₂/FIO₂ ratio < 300 mm Hg) were mechanically ventilated in a pressure controlled mode and placed on a kinetic treatment table. Measurements and results: Distributions of V_A/Q were determined 1) during rotation (after a period of 20 min) and 2) after a resting period of 20 min in the supine position. During axial rotation, intrapulmonary shunt (19.1 ± 15 % of cardiac output) was significantly reduced in comparison with when in the supine position (23 ± 14 %, p < 0.05), areas with “low” V_A/Q were not affected by the positioning maneuver. General V_A/Q mismatch (logarithmic distribution of pulmonary blood flow) was decreased during rotation (0.87 ± 0.37) in comparison with when the patient was in the supine position (0.93 ± 0.37, p < 0.05). Arterial oxygenation was significantly improved during continuous rotation (PaO₂/FIO₂ = 217 ± 137 mm Hg) as compared with in the supine position (PaO₂/FIO₂ = 174 ± 82 mm Hg, p < 0.05). The positive response of the continuous rotation on arterial oxygenation was only demonstrated in patients with a Murray Score of 2.5 or less, indicating a “mild to moderate” lung injury, while in patients presenting with progressive ARDS (Murray Score > 2.5), the acute positive response was limited. Conclusions: Continuous axial rotation might be a method for an acute reduction of V_A/Q mismatch in patients with mild to moderate ALI, but this technique is not effective in late or progressive ARDS. Further studies including a large data collection are needed. Received: 19 June 1997 Accepted: 6 November 1997     

Soluble intercellular adhesion molecule-1 and clinical outcomes in patients with acute lung injury

Objective  To determine if levels of soluble intercellular adhesion molecule-1 (sICAM-1), a marker of alveolar epithelial and endothelial injury, differ in patients with hydrostatic pulmonary edema and acute lung injury (ALI) and are associated with clinical outcomes in patients with ALI. Design, setting, and participants  Measurement of sICAM-1 levels in (1) plasma and edema fluid from 67 patients with either hydrostatic pulmonary edema or ALI enrolled in an observational, prospective single center study, and (2) in plasma from 778 patients with ALI enrolled in a large multi-center randomized controlled trial of ventilator strategy. Results  In the single-center study, levels of sICAM-1 were significantly higher in both edema fluid and plasma (median 938 and 545 ng/ml, respectively) from ALI patients compared to hydrostatic edema patients (median 384 and 177 ng/ml, P < 0.03 for both comparisons). In the multi-center study, higher plasma sICAM-1 levels were associated with poor clinical outcomes in both unadjusted and multivariable models. Subjects with ALI whose plasma sICAM-1 levels increased over the first 3 days of the study had a higher risk of death, after adjusting for other important predictors of outcome (odds ratio 1.48; 95% CI 1.03–2.12, P = 0.03). Conclusions  Both plasma and edema fluid levels of sICAM-1 are higher in patients with ALI than in patients with hydrostatic pulmonary edema. Higher plasma sICAM-1 levels and increasing sICAM-1 levels over time are associated with poor clinical outcomes in ALI. Measurement of sICAM-1 levels may be useful for identifying patients at highest risk of poor outcomes from ALI. The members of the NHLBI ARDS Clinical Trials Network are listed in the Appendix.     

An attempt to validate the modification of the American-European consensus definition of acute lung injury/acute respiratory distress syndrome by the Berlin definition in a university hospital

Purpose

The Berlin definition for acute respiratory distress syndrome (ARDS) is a new proposal for changing the American-European consensus definition but has not been assessed prospectively as yet. In the present study, we aimed to determine (1) the prevalence and incidence of ARDS with both definitions, and (2) the initial characteristics of patients with ARDS and 28-day mortality with the Berlin definition.

Methods

We performed a 6-month prospective observational study in the ten adult ICUs affiliated to the Public University Hospital in Lyon, France, from March to September 2012. Patients under invasive or noninvasive mechanical ventilation, with PaO₂/FiO₂ <300 mmHg regardless of the positive end-expiratory pressure (PEEP) level, and acute onset of new or increased bilateral infiltrates or opacities on chest X-ray were screened from ICU admission up to discharge. Patients with cardiogenic pulmonary edema were excluded. Patients were further classified into specific categories by using the American-European Consensus Conference and the Berlin definition criteria. The complete data set was measured at the time of inclusion. Patient outcome was measured at day 28 after inclusion.

Results

During the study period 3,504 patients were admitted and 278 fulfilled the American-European Consensus Conference criteria. Among them, 18 (6.5 %) did not comply with the Berlin criterion PEEP ≥ 5 cmH₂O and 20 (7.2 %) had PaO₂/FiO₂ ratio ≤200 while on noninvasive ventilation. By using the Berlin definition in the remaining 240 patients (n = 42 mild, n = 123 moderate, n = 75 severe), the overall prevalence was 6.85 % and it was 1.20, 3.51, and 2.14 % for mild, moderate, and severe ARDS, respectively (P > 0.05 between the three groups). The incidence of ARDS amounted to 32 per 100,000 population per year, with values for mild, moderate, and severe ARDS of 5.6, 16.3, and 10 per 100,000 population per year, respectively (P < 0.05 between the three groups). The 28-day mortality was 35.0 %. It amounted to 30.9 % in mild, 27.9 % in moderate, and 49.3 % in severe categories (P < 0.01 between mild or moderate and severe, P = 0.70 between mild and moderate). In the Cox proportional hazard regression analysis ARDS stage was not significantly associated with patient death at day 28.

Conclusions

The present study did not validate the Berlin definition of ARDS. Neither the stratification by severity nor the PaO₂/FiO₂ at study entry was independently associated with mortality.     

Coronavirus Disease 2019 Phenotypes,Lung Ultrasound,Chest Computed Tomography and Clinical Features in Critically Ill Mechanically Ventilated Patients

Chest computed tomography (CT) may provide insights into the pathophysiology of coronavirus disease 2019 (COVID-19), although it is not suitable for a timely bedside dynamic assessment of patients admitted to intensive care unit (ICU); therefore, lung ultrasound (LUS) has been proposed as a complementary diagnostic tool. The aims of this study were to investigate different lungs phenotypes in patients with COVID-19 and to assess the differences in CT and LUS scores between ICU survivors and non-survivors. We also explored the association between CT and LUS, and oxygenation (arterial partial pressure of oxygen [PaO₂]/fraction of inspired oxygen [FiO_2]) and clinical parameters. The study included 39 patients with COVID-19. CT scans revealed types 1, 2 and 3 phenotypes in 62%, 28% and 10% of patients, respectively. Among survivors, pattern 1 was prevalent (p < 0.005). Chest CT and LUS scores differed between survivors and non-survivors both at ICU admission and 10 days after and were associated with ICU mortality. Chest CT score was positively correlated with LUS findings at ICU admission (r = 0.953, p < 0.0001) and was inversely correlated with PaO₂/FiO₂ (r = –0.375, p = 0.019) and C-reactive protein (r = 0.329, p = 0.041). LUS score was inversely correlated with PaO₂/FiO₂ (r = –0.345, p = 0.031). COVID-19 presents distinct phenotypes with differences between survivors and non-survivors. LUS is a valuable monitoring tool in an ICU setting because it may correlate with CT findings and mortality, although it cannot predict oxygenation changes.     

COVID-19 and non-COVID ARDS patients demonstrate a distinct response to low dose steroids- A retrospective observational study

Patients with COVID-19 ARDS have distinct physiological and immunological phenotypes compared to patients with non-COVID ARDS. Patients with COVID-19 ARDS (n = 32) had a significant improvement in PaO₂: FiO₂ ratio (p = 0.046) following low-dose steroid treatment, unlike patients with non-COVID ARDS (n = 16) (p = 0.529). Patients with COVID-19 ARDS had a greater fall in CRP compared to patients with non-COVID ARDS, albeit not statistically significant (p = 0.07). Our novel findings highlight differences in the underlying physiological and immunological phenotypes between COVID-19 and non-COVID ARDS, with implications for future ARDS studies.     

High survival rate in 122 ARDS patients managed according to a clinical algorithm including extracorporeal membrane oxygenation

Objective: We investigated whether a treatment according to a clinical algorithm could improve the low survival rates in acute respiratory distress syndrome (ARDS). Design: Uncontrolled prospective trial. Setting: One university hospital intensive care department. Patients and participants: 122 patients with ARDS, consecutively admitted to the ICU. Interventions: ARDS was treated according to a criteria-defined clinical algorithm. The algorithm distinguished two main treatment groups: The AT-sine-ECMO (advanced treatment without extracorporeal membrane oxygenation) group (n = 73) received a treatment consisting of a set of advanced non-invasive treatment options, the ECMO treatment group (n = 49) received additional extracorporeal membrane oxygenation (ECMO) using heparin-coated systems. Measurements and results: The groups differed in both APACHE II (16 ± 5 vs 18 ± 5 points, p = 0.01) and Murray scores (3.2 ± 0.3 vs 3.4 ± 0.3 points, p = 0.0001), the duration of mechanical ventilation prior to admission (10 ± 9 vs 13 ± 9 days, p = 0.0151), and length of ICU stay in Berlin (31 ± 17 vs 50 ± 36 days, p = 0.0016). Initial PaO₂/FIO₂ was 86 ± 27 mm Hg in AT-sine-ECMO patients that improved to 165 ± 107 mm Hg on ICU day 1, while ECMO patients showed an initial PaO₂/FIO₂ of 67 ± 28 mm Hg and improvement to 160 ± 102 mm Hg was not reached until ICU day 13. Q˙_S/Q˙_T was significantly higher in the ECMO-treated group and exceeded 50 % during the first 14 ICU days. The overall survival rate in our 122 ARDS patients was 75 %. Survival rates were 89 % in the AT-sine ECMO group and 55 % in the ECMO treatment group (p = 0.0000). Conclusions: We conclude that patients with ARDS can be successfully treated with the clinical algorithm and high survival rates can be achieved. Received: 9 April 1997 Accepted: 13 May 1997     

N-terminal pro-brain natriuretic peptide as a marker of right ventricular dysfunction after open-lung approach in patients with acute lung injury/acute respiratory distress syndrome

Purpose

The purpose of the study was to evaluate the utility of N-terminal pro-brain natriuretic peptide (NT-proBNP) as a marker of right ventricular (RV) dysfunction after open-lung approach (OLA) in patients with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS).

Materials and Methods

Twenty-seven patients with ALI/ARDS underwent OLA (2-minute steps of fixed pressure-controlled ventilation with progressive positive end-expiratory pressure levels up to 30 cm H₂O, followed by stepwise decrement of positive end-expiratory pressure level by 2 cm H₂O). Patients who showed a PaO₂/FiO₂ increase of more than 50% from baseline were defined as responders. Plasma NT-proBNP levels were taken immediately before OLA and 2 and 6 hours later. A minimum 30% increase in NT-proBNP level from baseline was considered significant.

Results

Right-over-left ventricular stroke work ratio and its percentage change did not differ between responders and nonresponders, whereas these values were higher in patients showing NT-proBNP increase (P < .05). The NT-proBNP percentage change correlated with right-over-left ventricular stroke work ratio percentage change (r = 0.83), pulmonary vascular resistance (r = 0.81), and RV ejection fraction (r = -0.79) and correlated with plateau pressure in nonresponders only (r = 0.82).

Conclusions

In patients with ALI/ARDS, intraindividual NT-proBNP changes correlated with RV afterload following OLA, thereby serving as a potential marker for RV dysfunction after OLA.     

Effects of early rehabilitation therapy on patients with mechanical ventilation

BACKGROUND:

For patients in intensive care unit (ICU), mechanical ventilation is an effective treatment to survive from acute illness and improve survival rates. However, long periods of bed rest and restricted physical activity can result in side effects. This study aimed to investigate the feasibility of early rehabilitation therapy in patients with mechanical ventilation.

METHODS:

A randomized controlled trial was carried out. Sixty patients, with tracheal intubation or tracheostomy more than 48 hours and less than 72 hours, were admitted to the ICU of the Affiliated Hospital of Medical College, Qingdao University, from May 2010 to May 2012. These patients were randomly divided into a rehabilitation group and a control group. In the rehabilitation group, rehabilitation therapy was performed twice daily, and the training time and intensity were adjusted according to the condition of the patients. Early rehabilitation therapy included heading up actively, transferring from the supine position to sitting position, sitting at the edge of the bed, sitting in chair, transferring from sitting to standing, and ambulating bedside. The patient''s body mass index, days to first out of bed, duration of mechanical ventilation, length of ICU stay, APACHE II score, highest FiO₂, lowest PaO₂/FiO₂ and hospital mortality of patients were all compared between the rehabilitation group and the control group. The differences between the two groups were compared using Student''s t test.

RESULTS:

There was no significant difference in body mass index, APACHE II score, highest FiO₂, lowest PaO₂/FiO₂ and hospital mortality between the rehabilitation group and the control group (P>0.05). Patients in the rehabilitation group had shorter days to first out of bed (3.8±1.2 d vs. 7.3±2.8 d; P=0.00), duration of mechanical ventilation (5.6±2.1 d vs. 12.7±4.1 d; P=0.005) and length of ICU stay (12.7±4.1 d vs. 15.2±4.5 d; P=0.01) compared with the control group.

CONCLUSION:

Early rehabilitation therapy was feasible and effective in improving the outcomes of patients with mechanical ventilation.KEYWORDS: Early rehabilitation therapy, Mechanical ventilation, Intensive care unit, Hospital mortality, APACHE II score     

Incidence and prognostic value of right ventricular failure in acute respiratory distress syndrome

Objective  To analyse the incidence and the impact on outcome of right ventricular failure (RVF) in patients with acute respiratory distress syndrome (ARDS). Patients and methods  A total of 145 ARDS patients included in the previously published French Pulmonary Artery Catheter (PAC) study were randomly assigned to receive a PAC. All patients were ventilated according to a strategy aimed at limiting plateau pressure. The RVF was defined by the concomitant presence of: (1) a mean pulmonary artery pressure (MPAP) > 25 mmHg, (2) a central venous pressure (CVP) higher than pulmonary artery occlusion pressure (PAOP) and (3) a stroke volume index < 30 mL m⁻². Results  Right ventricular failure was present in 9.6% of patients. Mortality was 68% at day-90 with no difference between patients with RVF (RVF+) and without RVF (71 vs. 67%, respectively). SAPS II, PaO₂/FiO₂ and PaCO₂ were similar in both groups. Tidal volume and I/E ratio were significantly higher in RVF+ (9.7 ± 2.8 vs. 8.6 ± 1.8 ml m⁻² and 0.7 ± 0.5 vs. 0.5 ± 0.2). Plateau pressure tended to be higher in RVF+ (28 ± 6 vs. 25 ± 6 cmH₂O, NS). In multivariate analysis, PaO₂/FiO₂, mean arterial pressure, arterial pH, SvO₂, MPAP and presence of CVP > PAOP, but not RVF, were independently associated with day-90 mortality. Conclusion  In this group of patients investigated early in the course of ARDS and ventilated according to a strategy aimed at limiting plateau pressure, the presence of RVF was about 10%. Unlike MPAP and the presence of CVP > PAOP, RVF at this early stage did not appear as an independent factor of mortality. This article is discussed in the editorial available at: doi:.