Nonlinear Imputation of Pao2/Fio2 From Spo2/Fio2 Among Patients With Acute Respiratory Distress Syndrome

Predictors of hypoxemia in type-B acute aortic syndrome: a retrospective study

Acute aortic syndrome (AAS) can be life-threatening owing to a variety of complications, and it is managed in the intensive care unit (ICU). Although Stanford type-B AAS may involve hypoxemia, its predictors are not yet clearly understood. We studied clinical factors and imaging parameters for predicting hypoxemia after the onset of type-B AAS. We retrospectively analyzed patients diagnosed with type-B AAS in our hospital between January 2012 and April 2020. We defined hypoxemia as PaO₂/FiO₂ ≤ 200 within 7 days after AAS onset and used logistic regression analysis to evaluate prognostic factors for hypoxemia. We analyzed 224 consecutive patients (140 males, mean age 70 ± 14 years) from a total cohort of 267 patients. Among these, 53 (23.7%) had hypoxemia. The hypoxemia group had longer ICU and hospital stays compared with the non-hypoxemia group (median 20 vs. 16 days, respectively; p = 0.039 and median 7 vs. 5 days, respectively; p < 0.001). Male sex (odds ratio [OR] 2.87; 95% confidence interval [CI] 1.24–6.63; p = 0.014), obesity (OR 2.36; 95% CI 1.13–4.97; p = 0.023), patent false lumen (OR 2.33; 95% CI 1.09–4.99; p = 0.029), and high D-dimer level (OR 1.01; 95% CI 1.00–1.02; p = 0.047) were independently associated with hypoxemia by multivariate logistic analysis. This study showed a significant difference in duration of ICU and hospital stays between patients with and without hypoxemia. Furthermore, male sex, obesity, patent false lumen, and high D-dimer level may be significantly associated with hypoxemia in patients with type-B AAS.

Prognostication using SpO2/FiO2 in invasively ventilated ICU patients with ARDS due to COVID-19 - Insights from the PRoVENT-COVID study

Background

The SpO₂/FiO₂ is a useful oxygenation parameter with prognostic capacity in patients with ARDS. We investigated the prognostic capacity of SpO₂/FiO₂ for mortality in patients with ARDS due to COVID–19.

Methods

This was a post-hoc analysis of a national multicenter cohort study in invasively ventilated patients with ARDS due to COVID–19. The primary endpoint was 28–day mortality.

Results

In 869 invasively ventilated patients, 28–day mortality was 30.1%. The SpO₂/FiO₂ on day 1 had no prognostic value. The SpO₂/FiO₂ on day 2 and day 3 had prognostic capacity for death, with the best cut-offs being 179 and 199, respectively. Both SpO₂/FiO₂ on day 2 (OR, 0.66 [95%–CI 0.46–0.96]) and on day 3 (OR, 0.70 [95%–CI 0.51–0.96]) were associated with 28–day mortality in a model corrected for age, pH, lactate levels and kidney dysfunction (AUROC 0.78 [0.76–0.79]). The measured PaO₂/FiO₂ and the PaO₂/FiO₂ calculated from SpO₂/FiO₂ were strongly correlated (Spearman's r = 0.79).

Conclusions

In this cohort of patients with ARDS due to COVID–19, the SpO₂/FiO₂ on day 2 and day 3 are independently associated with and have prognostic capacity for 28–day mortality. The SpO₂/FiO₂ is a useful metric for risk stratification in invasively ventilated COVID–19 patients.

Clinical characteristics and in-hospital mortality of patients with COVID-19 in Chile: A prospective cohort study

AIMS OF THIS STUDY

To describe the Latin American population affected by COVID-19, and to determine relevant risk factors for in-hospital mortality.

METHODS

We prospectively registered relevant clinical, laboratory, and radiological data of adult patients with COVID-19, admitted within the first 100 days of the pandemic from a single teaching hospital in Santiago, Chile. The primary outcome was in-hospital mortality. Secondary outcomes included the need for respiratory support and pharmacological treatment, among others. We combined the chronic disease burden and the severity of illness at admission with predefined clinically relevant risk factors. Cox regression models were used to identify risk factors for in-hospital mortality.

RESULTS

We enrolled 395 adult patients, their median age was 61 years; 62.8% of patients were male and 40.1% had a Modified Charlson Comorbidity Index (MCCI) ≥5. Their median Sequential Organ Failure Assessment (SOFA) score was 3; 34.9% used a high-flow nasal cannula and 17.5% required invasive mechanical ventilation. The in-hospital mortality rate was 14.7%. In the multivariate analysis, were significant risk factors for in-hospital mortality: MCCI ≥5 (HR 4.39, P < .001), PaO₂ /FiO₂ ratio ≤200 (HR 1.92, P = .037), and advanced chronic respiratory disease (HR 3.24, P = .001); pre-specified combinations of these risk factors in four categories was associated with the outcome in a graded manner.

CONCLUSIONS AND CLINICAL IMPLICATIONS

The relationship between multiple prognostic factors has been scarcely reported in Latin American patients with COVID-19. By combining different clinically relevant risk factors, we can identify COVID-19 patients with high-, medium- and low-risk of in-hospital mortality.

Promises and challenges of personalized medicine to guide ARDS therapy

Identifying new effective treatments for the acute respiratory distress syndrome (ARDS), including COVID-19 ARDS, remains a challenge. The field of ARDS investigation is moving increasingly toward innovative approaches such as the personalization of therapy to biological and clinical sub-phenotypes. Additionally, there is growing recognition of the importance of the global context to identify effective ARDS treatments. This review highlights emerging opportunities and continued challenges for personalizing therapy for ARDS, from identifying treatable traits to innovative clinical trial design and recognition of patient-level factors as the field of critical care investigation moves forward into the twenty-first century.

Mortality Prediction Using SaO2/FiO2 Ratio Based on eICU Database Analysis

Purpose

PaO₂ to FiO₂ ratio (P/F) is used to assess the degree of hypoxemia adjusted for oxygen requirements. The Berlin definition of Acute Respiratory Distress Syndrome (ARDS) includes P/F as a diagnostic criterion. P/F is invasive and cost-prohibitive for resource-limited settings. SaO₂/FiO₂ (S/F) ratio has the advantages of being easy to calculate, noninvasive, continuous, cost-effective, and reliable, as well as lower infection exposure potential for staff, and avoids iatrogenic anemia. Previous work suggests that the SaO₂/FiO₂ ratio (S/F) correlates with P/F and can be used as a surrogate in ARDS. Quantitative correlation between S/F and P/F has been verified, but the data for the relative predictive ability for ICU mortality remains in question. We hypothesize that S/F is noninferior to P/F as a predictive feature for ICU mortality. Using a machine-learning approach, we hope to demonstrate the relative mortality predictive capacities of S/F and P/F.

Methods

We extracted data from the eICU Collaborative Research Database. The features age, gender, SaO₂, PaO₂, FIO₂, admission diagnosis, Apache IV, mechanical ventilation (MV), and ICU mortality were extracted. Mortality was the dependent variable for our prediction models. Exploratory data analysis was performed in Python. Missing data was imputed with Sklearn Iterative Imputer. Random assignment of all the encounters, 80% to the training (n = 26690) and 20% to testing (n = 6741), was stratified by positive and negative classes to ensure a balanced distribution. We scaled the data using the Sklearn Standard Scaler. Categorical values were encoded using Target Encoding. We used a gradient boosting decision tree algorithm variant called XGBoost as our model. Model hyperparameters were tuned using the Sklearn RandomizedSearchCV with tenfold cross-validation. We used AUC as our metric for model performance. Feature importance was assessed using SHAP, ELI5 (permutation importance), and a built-in XGBoost feature importance method. We constructed partial dependence plots to illustrate the relationship between mortality probability and S/F values.

Results

The XGBoost hyperparameter optimized model had an AUC score of .85 on the test set. The hyperparameters selected to train the final models were as follows: colsample_bytree of 0.8, gamma of 1, max_depth of 3, subsample of 1, min_child_weight of 10, and scale_pos_weight of 3. The SHAP, ELI5, and XGBoost feature importance analysis demonstrates that the S/F ratio ranks as the strongest predictor for mortality amongst the physiologic variables. The partial dependence plots illustrate that mortality rises significantly above S/F values of 200.

Conclusion

S/F was a stronger predictor of mortality than P/F based upon feature importance evaluation of our data. Our study is hypothesis-generating and a prospective evaluation is warranted. Take-Home Points. S/F ratio is a noninvasive continuous method of measuring hypoxemia as compared to P/F ratio. Our study shows that the S/F ratio is a better predictor of mortality than the more widely used P/F ratio to monitor and manage hypoxemia.

Impact of Air Transport on SpO2/FiO2 among Critical COVID-19 Patients during the First Pandemic Wave in France

During the first wave of the COVID-19 pandemic, some French regions were more affected than others. To relieve those areas most affected, the French government organized transfers of critical patients, notably by plane or helicopter. Our objective was to investigate the impact of such transfers on the pulse oximetric saturation (SpO₂)-to-inspired fraction of oxygen (FiO₂) ratio among transferred critical patients with COVID-19. We conducted a retrospective study on medical and paramedical records. The primary endpoint was the change in SpO₂/FiO₂ during transfers. Thirty-eight patients were transferred between 28 March and 5 April 2020, with a mean age of 62.4 years and a mean body mass index of 29.8 kg/m². The population was 69.7% male, and the leading medical history was hypertension (42.1%), diabetes (34.2%), and dyslipidemia (18.4%). Of 28 patients with full data, we found a decrease of 28.9 points in SpO₂/FiO₂ (95% confidence interval, 5.8 to 52.1, p = 0.01) between the starting and the arrival intensive care units (SpO₂/FiO₂, 187.3 ± 61.3 and 158.4 ± 62.8 mmHg, respectively). Air medical transfers organized to relieve intensive care unit teams under surging conditions during the first COVID wave were associated with significant decreases in arterial oxygenation.

Intravenous Methylene Blue as a Rescue Therapy in the Management of Refractory Hypoxia in COVID-19 ARDS Patients: A Case Series

Objectives: To describe the clinical outcomes of hypoxic coronavirus disease 2019 (COVID-19) patients treated with intravenous methylene blue (MB) in a tertiary care hospital.

Materials and methods: We conducted a case series of 50 patients with hypoxic COVID-19 treated with intravenous MB admitted to our hospital between June 01 and September 10, 2020. Intravenous MB was administered as rescue therapy in dosage of 1 mg/kg body weight, with a maximum of five doses, to patients with high oxygen requirements (SpO₂/FiO₂ <200) apart from the standard of care after obtaining G6PD levels. Data were abstracted from multiple electronic data sources or patient charts to provide information on patient characteristics, clinical and laboratory variables and outcomes.

Results: The median age of the patients was 53.3 (range 25–74 years) and most patients (74%) were men. About 68% of patients had pre-existing comorbidity. Median SpO₂/FiO₂ ratio progressively improved from 132.5 (predose) to 284 before the terminal event (death or discharge), ventilator-free days, and decrease in the proinflammatory biochemical parameter was significantly higher after the second dose of MB. A total of six patients out of 50 required invasive mechanical ventilation (IMV). Thirty patients were discharged with a recovery rate of 60%, while 20 patients succumbed to the illness. There was no major side effect or adverse event reported in any of the patients.

Conclusion: MB due to its polypharmacological action against SARS‐CoV‐2, an inexpensive and widely available drug with minimal side effects, has a significant potential in the treatment of COVID-19.

How to cite this article: Mahale N, Godavarthy P, Marreddy S, Gokhale SD, Funde P, Rajhans PA, et al. Intravenous Methylene Blue as a Rescue Therapy in the Management of Refractory Hypoxia in COVID-19 ARDS Patients: A Case Series. Indian J Crit Care Med 2021;25(8):934–938.

Pneumonia Severity Index and CURB-65 Are Good Predictors of Mortality in Hospitalized Patients with SARS-CoV-2 Community-Acquired Pneumonia

Background

The Confusion, Urea > 7 mM, Respiratory Rate ≥ 30 breaths/min, BP < 90 mm Hg (Systolic) or < 60 mm Hg (Diastolic), Age ≥ 65 Years (CURB-65) score and the Pneumonia Severity Index (PSI) are well-established clinical prediction rules for predicting mortality in patients hospitalized with community-acquired pneumonia (CAP). SARS-CoV-2 has emerged as a new etiologic agent for CAP, but the role of CURB-65 score and PSI have not been established.

Research Question

How effective are CURB-65 score and PSI at predicting in-hospital mortality resulting from SARS-CoV-2 CAP compared with non-SARS-CoV-2 CAP? Can these clinical prediction rules be optimized to predict mortality in SARS-CoV-2 CAP by addition of procalcitonin and D-dimer?

Study Design and Methods

Secondary analysis of two prospective cohorts of patients with SARS-CoV-2 CAP or non-SARS-CoV-2 CAP from eight adult hospitals in Louisville, Kentucky.

Results

The in-hospital mortality rate was 19% for patients with SARS-CoV-2 CAP and 6.5% for patients with non-SARS-CoV-2 CAP. For the PSI score, receiver operating characteristic (ROC) curve analysis resulted in an area under the ROC curve (AUC) of 0.82 (95% CI, 0.78-0.86) and 0.79 (95% CI, 0.77-0.80) for patients with SARS-CoV-2 CAP and non-SARS-CoV-2 CAP, respectively. For the CURB-65 score, ROC analysis resulted in an AUC of 0.79 (95% CI, 0.75-0.84) and 0.75 (95% CI, 0.73-0.77) for patients with SARS-CoV-2 CAP and non-SARS-CoV-2 CAP, respectively. In SARS-CoV-2 CAP, the addition of D-dimer (optimal cutoff, 1,813 μg/mL) and procalcitonin (optimal cutoff, 0.19 ng/mL) to PSI and CURB-65 score provided negligible improvement in prognostic performance.

Interpretation

PSI and CURB-65 score can predict in-hospital mortality for patients with SARS-CoV-2 CAP and non-SARS-CoV-2 CAP comparatively. In patients with SARS-CoV-2 CAP, the inclusion of either D-dimer or procalcitonin to PSI or CURB-65 score did not improve the prognostic performance of either score. In patients with CAP, regardless of cause, PSI and CURB-65 score remain adequate for predicting mortality in clinical practice.

Pepsin A in Tracheal Secretions From Patients Receiving Mechanical Ventilation

BACKGROUND

In patients in the intensive care unit (ICU) receiving mechanical ventilation, aspiration of gastric contents may lead to ventilator-associated events and other adverse outcomes. Pepsin in pulmonary secretions is a biomarker of microaspiration of gastric contents.

OBJECTIVES

To evaluate the association between tracheal pepsin A and clinical outcomes related to ventilator use.

METHODS

A subset of 297 patients from a larger clinical trial on aspiration of oral secretions in adults receiving mechanical ventilation consented to have pepsin A measured in their tracheal aspirate samples. A concentration ≥6.25 ng/mL indicated a positive result. Abundant microaspiration was defined as pepsin A in ≥30% of samples. Statistical analyses included analysis of variance, analysis of covariance, and χ2 tests.

RESULTS

Most patients were White men, mean age 59.7 (SD, 18.8) years. Microaspiration was found in 43.8% of patients (n = 130), with abundant microaspiration detected in 17.5% (n = 52). After acuity was controlled for, patients with tracheal pepsin A had a longer mechanical ventilation duration (155 vs 104 hours, P < .001) and ICU stay (9.9 vs 8.2 days, P = .04), but not a longer hospital stay.

CONCLUSIONS

Microaspiration of gastric contents occurred in nearly half of patients and was associated with a longer duration of mechanical ventilation and a longer stay in the ICU. Additional preventative interventions beyond backrest elevation, oropharyngeal suctioning, and management of endotracheal tube cuff pressure may be needed. Also, the timing of pepsin measurements to capture all microaspiration events requires additional exploration.

Comparing Clinical Features and Outcomes in Mechanically Ventilated Patients with COVID-19 and Acute Respiratory Distress Syndrome

Rationale: Patients with severe coronavirus disease (COVID-19) meet clinical criteria for the acute respiratory distress syndrome (ARDS), yet early reports suggested they differ physiologically and clinically from patients with non-COVID-19 ARDS, prompting treatment recommendations that deviate from standard evidence-based practices for ARDS. Objectives: To compare respiratory physiology, clinical outcomes, and extrapulmonary clinical features of severe COVID-19 with non-COVID-19 ARDS. Methods: We performed a retrospective cohort study, comparing 130 consecutive mechanically ventilated patients with severe COVID-19 with 382 consecutive mechanically ventilated patients with non-COVID-19 ARDS. Initial respiratory physiology and 28-day outcomes were compared. Extrapulmonary manifestations (inflammation, extrapulmonary organ injury, and coagulation) were compared in an exploratory analysis. Results: Comparison of patients with COVID-19 and non-COVID-19 ARDS suggested small differences in respiratory compliance, ventilatory efficiency, and oxygenation. The 28-day mortality was 30% in patients with COVID-19 and 38% in patients with non-COVID-19 ARDS. In adjusted analysis, point estimates of differences in time to breathing unassisted at 28 days (adjusted subdistributional hazards ratio, 0.98 [95% confidence interval (CI), 0.77-1.26]) and 28-day mortality (risk ratio, 1.01 [95% CI, 0.72-1.42]) were small for COVID-19 versus non-COVID-19 ARDS, although the confidence intervals for these estimates include moderate differences. Patients with COVID-19 had lower neutrophil counts but did not differ in lymphocyte count or other measures of systemic inflammation. Conclusions: In this single-center cohort, we found no evidence for large differences between COVID-19 and non-COVID-19 ARDS. Many key clinical features of severe COVID-19 were similar to those of non-COVID-19 ARDS, including respiratory physiology and clinical outcomes, although our sample size precludes definitive conclusions. Further studies are needed to define COVID-19-specific pathophysiology before a deviation from evidence-based treatment practices can be recommended.

A Comparative Analysis of the Respiratory Subscore of the Sequential Organ Failure Assessment Scoring System

Rationale: The Sequential Organ Failure Assessment (SOFA) tool is a commonly used measure of illness severity. Calculation of the respiratory subscore of SOFA is frequently limited by missing arterial oxygen pressure (PaO2) data. Although missing PaO2 data are commonly replaced with normal values, the performance of different methods of substituting PaO2 for SOFA calculation is unclear. Objectives: The study objective was to compare the performance of different substitution strategies for missing PaO2 data for SOFA score calculation. Methods: This retrospective cohort study was performed using the Weill Cornell Critical Care Database for Advanced Research from a tertiary care hospital in the United States. All adult patients admitted to an intensive care unit (ICU) from 2011 to 2019 with an available respiratory SOFA score were included. We analyzed the availability of the PaO2/fraction of inspired oxygen (FiO2) ratio on the first day of ICU admission. In those without a PaO2/FiO2 ratio available, the ratio of oxygen saturation as measured by pulse oximetry to FiO2 was used to calculate a respiratory SOFA subscore according to four methods (linear substitution [Rice], nonlinear substitution [Severinghaus], modified respiratory SOFA, and multiple imputation by chained equations [MICE]) as well as the missing-as-normal technique. We then compared how well the different total SOFA scores discriminated in-hospital mortality. We performed several subgroup and sensitivity analyses. Results: We identified 35,260 unique visits, of which 9,172 included predominant respiratory failure. PaO2 data were available for 14,939 (47%). The area under the receiver operating characteristic curve for each substitution technique for discriminating in-hospital mortality was higher than that for the missing-as-normal technique (0.78 [0.77-0.79]) in all analyses (modified, 0.80 [0.79-0.81]; Rice, 0.80 [0.79-0.81]; Severinghaus, 0.80 [0.79-0.81]; and MICE, 0.80 [0.79-0.81]) (P < 0.01). Each substitution method had a higher accuracy for discriminating in-hospital mortality (MICE, 0.67; Rice, 0.67; modified, 0.66; and Severinghaus, 0.66) than the missing-as-normal technique. Model calibration for in-hospital mortality was less precise for the missing-as-normal technique than for the other substitution techniques at the lower range of SOFA and among the subgroups. Conclusions: Using physiologic and statistical substitution methods improved the total SOFA score's ability to discriminate mortality compared with the missing-as-normal technique. Treating missing data as normal may result in underreporting the severity of illness compared with using substitution. The simplicity of a direct oxygen saturation as measured by pulse oximetry/FiO2 ratio-modified SOFA technique makes it an attractive choice for electronic health record-based research. This knowledge can inform comparisons of severity of illness across studies that used different techniques.

Acute respiratory distress syndrome: a life threatening associated complication of SARS-CoV-2 infection inducing COVID-19

Acute Respiratory Distress Syndrome (ARDS) is a form of respiratory failure in human. The number of deaths caused by SARS-CoV-2 infection inducing this severe pneumonia (ARDS) is relatively high. In fact, COVID-19 might get worsen in ARDS and provoke respiratory failure. A better understood of ARDS key features and the pathophysiological injuries of the pulmonary parenchyma are linked to lessons learned from previous severe diseases associated previous coronaviruses outbreaks (especially SARS-CoV and MERS-CoV) and more the ongoing SARS-CoV-2. The ARDS mechanism includes a diffuse alveolar damage associated disruption of alveolar capillary membrane, pulmonary edema, damaged endothelium and increased permeability. A diffuse inflammation, with acute onset, on the lung tissue accompanied by release of biochemical signal and inflammatory mediators (TNFα, IL-1 and IL-6) leading to hypoxemia, low PaO2/FiO2 ratio and the chest radiological expression of bilateral infiltrates in ARDS. The ongoing outbreak could lead to a better understood of ARDS pathophysiology and prognostic. An overview is also highlighted about the seven coronaviruses proved to infect human especially those having ability to cause severe disease SARS-CoV, MERS-CoV and SARS-CoV-2. In this review, we focused on the major pathological mechanisms leading to the ARDS development as a result of viral infection, severe COVID-19 worsening. Communicated by Ramaswamy H. Sarma.

Role of SpO2/FiO2 Ratio and ROX Index in Predicting Early Invasive Mechanical Ventilation in COVID-19. A Pragmatic, Retrospective, Multi-Center Study

The ability of COVID-19 to compromise the respiratory system has generated a substantial proportion of critically ill patients in need of invasive mechanical ventilation (IMV). The objective of this paper was to analyze the prognostic ability of the pulse oximetry saturation/fraction of inspired oxygen ratio (SpO2/FiO2) and the ratio of SpO2/FiO2 to the respiratory rate-ROX index-as predictors of IMV in an emergency department in confirmed COVID-19 patients. A multicenter, retrospective cohort study was carried out in four provinces of Spain between March and November 2020. The discriminative power of the predictive variable was assessed through a prediction model trained using a derivation sub-cohort and evaluated by the area under the curve (AUC) of the receiver operating characteristic (ROC) on the validation sub-cohort. A total of 2040 patients were included in the study. The IMV rate was 10.1%, with an in-hospital mortality rate of 35.3%. The performance of the SpO2/FiO2 ratio was better than the ROX index-AUC = 0.801 (95% CI 0.746-0.855) and AUC = 0.725 (95% CI 0.652-0.798), respectively. In fact, a direct comparison between AUCs resulted in significant differences (p = 0.001). SpO2 to FiO2 ratio is a simple and promising non-invasive tool for predicting risk of IMV in patients infected with COVID-19, and it is realizable in emergency departments.

Prediction of Extubation Failure in COVID-19

BACKGROUND

[Formula: see text] may be a reliable noninvasive alternative to the [Formula: see text] index. Furthermore, the ROX index (ie, the ratio of [Formula: see text] to breathing frequency) has been validated to predict high-flow nasal cannula failure in subjects under spontaneous breathing. However, these indices have not been tested in subjects with COVID-19 receiving invasive mechanical ventilation. This study aims to verify the correlation between both the ROX index and [Formula: see text] with [Formula: see text] and the ratio of [Formula: see text] to breathing frequency, and to determine the accuracy of the indices that use [Formula: see text] for the prediction of extubation failure in subjects with COVID-19.

METHODS

A prospective cohort study was conducted from May 15, 2020, to June 15, 2020, with subjects with COVID-19 on invasive mechanical ventilation. Indices using [Formula: see text] in the formula were compared to those using [Formula: see text]. Additionally, the performance of the indices in predicting extubation failure was evaluated.

RESULTS

This study included 69 subjects age 64.8 ± 14.6 y. There were no differences between the median values of the indices, including between the ROX index and [Formula: see text] to breathing frequency (P = .40) or between [Formula: see text] and [Formula: see text] (P = .83). When comparing the ROX index with the [Formula: see text] index to breathing frequency, they were found to be strongly correlated (R² = 0.75 [95% CI 0.6763-0.8152], P < .001). The comparison of [Formula: see text] with [Formula: see text] revealed R² = 0.70 (95% CI 0.563-0.749, P < .001). The area under the receiver operating characteristic curve for the ROX index to determine extubation failure was 0.74 (P = .01), whereas for [Formula: see text] it was 0.78 (P < .001).

CONCLUSIONS

The indices presented a good correlation in subjects with COVID-19 on invasive mechanical ventilation, and both the ROX index and [Formula: see text] can discriminate extubation failure in this population.

Long-term outcomes of patients following hospitalization for coronavirus disease 2019: a prospective observational study

OBJECTIVES

Few data are available regarding follow up of patients with coronavirus disease 2019 (COVID-19) after their discharge. We aim to describe the long-term outcomes of survivors of hospitalization for COVID-19 followed up first at an outpatient facility and subsequently by telephone.

METHODS

Observational prospective study conducted at a tertiary general hospital. Clinical and radiological progression was assessed and data were recorded on a standardized reporting form. Patients were divided into three groups according to Pao2/Fio2 at hospitalization: Pao2/Fio2 >300, Pao2/Fio2 300-200 and Pao2/Fio2 <200. A logistic multivariate regression model was performed to identify factors associated with persistence of symptoms.

RESULTS

For facility follow up, 302 individuals were enrolled. Median follow up was 45 days after discharge; 78% (228/294) of patients had COVID-19-related symptoms (53% asthenia, 56% respiratory symptoms) and 40% (122/302) had residual pulmonary radiographic lesions. Pao2/Fio2 <200 was an independent predictor of persistent dyspnoea (OR 1.87, 95% CI 1.38-2.52, p < 0.0001). Pao2/Fio2 >300 was associated with resolution of chest radiographic lesions (OR 0.56, 95% CI 0.42-0.74, p < 0.0001). Fifty per cent of patients required specific medical follow up after the first consultation and were transferred to another physician. A total of 294 patients were contacted for telephone follow up after a median follow-up time of 7 months. Fifty per cent of patients (147/294) still presented symptoms and 49% (145/294) had psychological disorders. Asthenia was identified in 27% (78/294) and dyspnoea in 10% (28/294) of patients independently of Pao2/Fio2.

CONCLUSIONS

Patients with COVID-19 require long-term follow up because of the persistence of symptoms; patients with low Pao2/Fio2 during the acute illness require special attention.

Importance of Lung Ultrasound Follow-Up in Patients Who Had Recovered from Coronavirus Disease 2019: Results from a Prospective Study

There is growing evidence regarding the imaging findings of coronavirus disease 2019 (COVID-19) in lung ultrasounds, however, their role in predicting the prognosis has yet to be explored. Our objective was to assess the usefulness of lung ultrasound in the short-term follow-up (1 and 3 months) of patients with SARS-CoV-2 pneumonia, and to describe the progression of the most relevant lung ultrasound findings. We conducted a prospective, longitudinal and observational study performed in patients with confirmed COVID-19 who underwent a lung ultrasound examination during hospitalization and repeated it 1 and 3 months after hospital discharge. A total of 96 patients were enrolled. In the initial ultrasound, bilateral involvement was present in 100% of the patients with mild, moderate or severe ARDS. The most affected lung area was the posteroinferior (93.8%) followed by the lateral (88.7%). Subpleural consolidations were present in 68% of the patients and consolidations larger than 1 cm in 24%. One month after the initial study, only 20.8% had complete resolution on lung ultrasound. This percentage rose to 68.7% at 3 months. Residual lesions were observed in a significant percentage of patients who recovered from moderate or severe ARDS (32.4% and 61.5%, respectively). In conclusion, lung injury associated with COVID-19 might take time to resolve. The findings in this report support the use of lung ultrasound in the short-term follow-up of patients recovered from COVID-19, as a radiation-sparing, easy to use, novel care path worth exploring.

Comparison of three cisatracurium dosing strategies in acute respiratory distress syndrome: A focus on drug utilization and improvement in oxygenation

Purpose

Three continuous dosing strategies of cisatracurium (CIS) for acute respiratory distress syndrome (ARDS) have been described in the literature. After implementation of a ventilator synchrony protocol (VSP), we sought to determine which continuous CIS dosing strategy utilized the least amount of drug without compromising efficacy.

Methods

We retrospectively reviewed patients with ARDS receiving continuous CIS from January 1, 2013 to December 31, 2018. We categorized patients into one of three dosing strategies: fixed dose (FD), titration based solely on train-of-four (TOF), or the VSP. We documented drug consumption and determined efficacy by comparing the change in PaO₂/FiO₂ ratio (P/F) and oxygenation index (OI) from baseline up to 48 h.

Results

A total of 1047 patients were screened, and 189 met inclusion criteria (VSP = 69, TOF = 99, FD = 21). Drug consumption (mg) was significantly lower in the VSP arm: 415 [IQR 318–528] compared to both the TOF: 665 [IQR 472–927] and the FD arms: 1730 [IQR 1695–1800], p < 0.001 for each. The change in P/F and OI from baseline were statistically equivalent at all time points.

Conclusion

Without impacting efficacy of gas exchange, a protocol using ventilator synchrony for CIS titration required significantly less drug compared to TOF-based titration and a fixed dosing regimen.

Time for a prehospital-modified sequential organ failure assessment score: An ambulance-Based cohort study

BACKGROUND

To adapt the Sequential Organ Failure Assessment (SOFA) score to fit the prehospital care needs; to do that, the SOFA was modified by replacing platelets and bilirubin, by lactate, and tested this modified SOFA (mSOFA) score in its prognostic capacity to assess the mortality-risk at 2 days since the first Emergency Medical Service (EMS) contact.

METHODS

Prospective, multicentric, EMS-delivery, ambulance-based, pragmatic cohort study of adults with acute diseases, referred to two tertiary care hospitals (Spain), between January 1st and December 31st, 2020. The discriminative power of the predictive variable was assessed through a prediction model trained using the derivation cohort and evaluated by the area under the curve (AUC) of the receiver operating characteristic (ROC) on the validation cohort.

RESULTS

A total of 1114 participants comprised two separated cohorts recruited from 15 ambulance stations. The 2-day mortality rate (from any cause) was 5.9% (66 cases). The predictive validity of the mSOFA score was assessed by the calculation of the AUC of ROC in the validation cohort, resulting in an AUC of 0.946 (95% CI, 0.913-0.978, p < .001), with a positive likelihood ratio was 23.3 (95% CI, 0.32-46.2).

CONCLUSIONS

Scoring systems are now a reality in prehospital care, and the mSOFA score assesses multiorgan dysfunction in a simple and agile manner either bedside or en route. Patients with acute disease and an mSOFA score greater than 6 points transferred with high priority by EMS represent a high early mortality group.

TRIAL REGISTRATION

ISRCTN48326533, Registered Octuber 312,019, Prospectively registered (doi:https://doi.org/10.1186/ISRCTN48326533).

Correlation and validity of imputed PaO2/FiO2 and SpO2/FiO2 in patients with invasive mechanical ventilation at 2600m above sea level

OBJECTIVE

To establish the correlation and validity between PaO2/FiO2 obtained on arterial gases versus noninvasive methods (linear, nonlinear, logarithmic imputation of PaO2/FiO2 and SpO2/FiO2) in patients under mechanical ventilation living at high altitude.

DESIGN

Ambispective descriptive multicenter cohort study.

SETTING

Two intensive care units (ICU) from Colombia at 2600m a.s.l.

PATIENTS OR PARTICIPANTS

Consecutive critically ill patients older than 18 years with at least 24h of mechanical ventilation were included from June 2016 to June 2019.

INTERVENTIONS

None.

VARIABLES

Variables analyzed were demographic, physiological messures, laboratory findings, oxygenation index and clinical condition. Nonlinear, linear and logarithmic imputation formulas were used to calculate PaO2 from SpO2, and at the same time the SpO2/FiO2 by severe hypoxemia diagnosis. The intraclass correlation coefficient, area under the ROC curve, sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratio were calculated.

RESULTS

The correlation between PaO2/FiO2 obtained from arterial gases, PaO2/FiO2 derived from one of the proposed methods (linear, non-linear, and logarithmic formula), and SpO2/FiO2 measured by the intraclass correlation coefficient was high (greater than 0.77, p<0.001). The different imputation methods and SpO2/FiO2 have a similar diagnostic performance in patients with severe hypoxemia (PaO2/FiO2 <150). PaO2/FiO2 linear imputation AUC ROC 0,84 (IC 0.81-0.87, p<0.001), PaO2/FiO2 logarithmic imputation AUC ROC 0.84 (IC 0.80-0.87, p<0.001), PaO2/FiO2 non-linear imputation AUC ROC 0.82 (IC 0.79-0.85, p<0.001), SpO2/FiO2 oximetry AUC ROC 0.84 (IC 0.81-0.87, p<0.001).

CONCLUSIONS

At high altitude, the SaO2/FiO2 ratio and the imputed PaO2/FiO2 ratio have similar diagnostic performance in patients with severe hypoxemia ventilated by various pathological conditions.

What about tocilizumab? A retrospective study from a NYC Hospital during the COVID-19 outbreak

BACKGROUND

Tocilizumab, an interleukin-6 receptor blocker, has been used in the inflammatory phase of COVID-19, but its impact independent of corticosteroids remains unclear in patients with severe disease.

METHODS

In this retrospective analysis of patients with COVID-19 admitted between March 2 and April 14, 2020 to a large academic medical center in New York City, we describe outcomes associated with tocilizumab 400 mg (without methylprednisolone) compared to a propensity-matched control. The primary endpoints were change in a 7-point ordinal scale of oxygenation and ventilator free survival, both at days 14 and 28. Secondary endpoints include incidence of bacterial superinfections and gastrointestinal perforation. Primary outcomes were evaluated using t-test.

RESULTS

We identified 33 patients who received tocilizumab and matched 74 controls based on demographics and health measures upon admission. After adjusting for illness severity and baseline ordinal scale, we failed to find evidence of an improvement in hypoxemia based on an ordinal scale at hospital day 14 in the tocilizumab group (OR 2.2; 95% CI, 0.7-6.5; p = 0.157) or day 28 (OR 1.1; 95% CI, 0.4-3.6; p = 0.82). There also was no evidence of an improvement in ventilator-free survival at day 14 (OR 0.8; 95% CI, 0.18-3.5; p = 0.75) or day 28 (OR 1.1; 95% CI, 0.1-1.8; p = 0.23). There was no increase in secondary bacterial infection rates in the tocilizumab group compared to controls (OR 0.37; 95% CI, 0.09-1.53; p = 0.168).

CONCLUSIONS

There was no evidence to support an improvement in hypoxemia or ventilator-free survival with use of tocilizumab 400 mg in the absence of corticosteroids. No increase in secondary bacterial infections was observed in the group receiving tocilizumab.

Association of Prehospital Oxygen Saturation to Inspired Oxygen Ratio With 1-, 2-, and 7-Day Mortality

IMPORTANCE

The early identification of patients at high risk of clinical deterioration represents one of the greatest challenges for emergency medical services (EMS).

OBJECTIVE

To assess whether use of the ratio of prehospital oxygen saturation measured by pulse oximetry (Spo2) to fraction of inspired oxygen (Fio2) measured during initial contact by EMS with the patient (ie, the first Spo2 to Fio2 ratio) and 5 minutes before the patient's arrival at the hospital (ie, the second Spo2 to Fio2 ratio) can predict the risk of early in-hospital deterioration.

DESIGN, SETTING, AND PARTICIPANTS

A prospective, derivation-validation prognostic cohort study of 3606 adults with acute diseases referred to 5 tertiary care hospitals in Spain was conducted between October 26, 2018, and June 30, 2020. Eligible patients were recruited from among all telephone requests for EMS assistance for adults who were later evacuated with priority in advanced life support units to the referral hospitals during the study period.

MAIN OUTCOMES AND MEASURES

The primary outcome was hospital mortality from any cause within the first, second, third, or seventh day after EMS transport to the hospital. The main measure was the Spo2 to Fio2 ratio.

RESULTS

A total of 3606 participants comprised 2 separate cohorts: the derivation cohort (3081 patients) and the validation cohort (525 patients). The median age was 69 years (interquartile range, 54-81 years), and 2122 patients (58.8%) were men. The overall mortality rate of the patients in the study cohort ranged from 3.6% for 1-day mortality (131 patients) to 7.1% for 7-day mortality (256 patients). The best model performance was for 2-day mortality with the second Spo2 to Fio2 ratio with an area under the curve of 0.890 (95% CI, 0.829-0.950; P < .001), although the other outcomes also presented good results. In addition, a risk-stratification model was generated. The optimal cutoff resulted in the following ranges of Spo2 to Fio2 ratios: 50 to 100 for high risk of mortality, 101 to 426 for intermediate risk, and 427 to 476 for low risk.

CONCLUSIONS AND RELEVANCE

This study suggests that use of the prehospital Spo2 to Fio2 ratio was associated with improved management of patients with acute disease because it accurately predicts short-term mortality.

Corticosteroid Pulses for Hospitalized Patients with COVID-19: Effects on Mortality

OBJECTIVES

To assess the influence of corticosteroid pulses on 60-day mortality in hospitalized patients with severe COVID-19.

METHODS

We designed a multicenter retrospective cohort study in three teaching hospitals of Castilla y León, Spain (865,096 people). We selected patients with confirmed COVID-19 and lung involvement with a pO2/FiO2<300, excluding those exposed to immunosuppressors before or during hospitalization, patients terminally ill at admission, or those who died in the first 24 hours. We performed a propensity score matching (PSM) adjusting covariates that modify the probability of being treated. Then, we used a Cox regression model in the PSM group to consider factors affecting mortality.

RESULTS

From 2933 patients, 257 fulfilled the inclusion and exclusion criteria. 124 patients were on corticosteroid pulses (250 mg of methylprednisolone for three days), and 133 were not. 30.3% (37/122) of patients died in the corticosteroid pulse group and 42.9% (57/133) in the nonexposed cohort. These differences (12.6%, 95% CI [8·54-16.65]) were statically significant (log-rank 4.72, p = 0, 03). We performed PSM using the exact method. Mortality differences remained in the PSM group (log-rank 5.31, p = 0.021) and were still significant after a Cox regression model (HR for corticosteroid pulses 0.561; p = 0.039).

CONCLUSIONS

This study provides evidence about treatment with corticosteroid pulses in severe COVID-19 that might significantly reduce mortality. Strict inclusion and exclusion criteria with that selection process set a reliable frame to compare mortality in both the exposed and nonexposed groups.

Assessment of the SpO2/FiO2 ratio as a tool for hypoxemia screening in the emergency department

Objective

We assessed the performance of the ratio of peripheral arterial oxygen saturation to the inspired fraction of oxygen (SpO₂/FiO₂) to predict the ratio of partial pressure arterial oxygen to the fraction of inspired oxygen (PaO₂/FiO₂) among patients admitted to our emergency department (ED) during the SARS-CoV-2 outbreak.

Methods

We retrospectively studied patients admitted to an academic-level ED in France who were undergoing a joint measurement of SpO₂ and arterial blood gas. We compared SpO₂ with SaO₂ and evaluated performance of the SpO₂/FiO₂ ratio for the prediction of 300 and 400 mmHg PaO₂/FiO₂ cut-off values in COVID-19 positive and negative subgroups using receiver-operating characteristic (ROC) curves.

Results

During the study period from February to April 2020, a total of 430 arterial samples were analyzed and collected from 395 patients. The area under the ROC curves of the SpO₂/FiO₂ ratio was 0.918 (CI 95% 0.885–0.950) and 0.901 (CI 95% 0.872–0.930) for PaO₂/FiO₂ thresholds of 300 and 400 mmHg, respectively. The positive predictive value (PPV) of an SpO₂/FiO₂ threshold of 350 for PaO₂/FiO₂ inferior to 300 mmHg was 0.88 (CI95% 0.84–0.91), whereas the negative predictive value (NPV) of the SpO₂/FiO₂ threshold of 470 for PaO₂/FiO₂ inferior to 400 mmHg was 0.89 (CI95% 0.75–0.96). No significant differences were found between the subgroups.

Conclusions

The SpO₂/FiO₂ ratio may be a reliable tool for hypoxemia screening among patients admitted to the ED, particularly during the SARS-CoV-2 outbreak.

Noninvasive SpO2/FiO2 ratio as surrogate for PaO2/FiO2 ratio during simulated prolonged field care and ground and high-altitude evacuation

BACKGROUND

Diagnosis of lung injury requires invasive blood draws to measure oxygen tension in blood. This capability is nonexistent in austere settings and during prolonged field care (PFC), that is, medical care characterized by inability to evacuate casualties from the point of injury for up to 72 hours. We analyzed pulse-oximeter-derived noninvasive SpO2 and assessed the SpO2/FiO2 ratio (SFR) as a surrogate for the PaO2/FiO2 ratio (PFR), an accepted marker of lung function. We hypothesized that SFR is a suitable surrogate for PFR in a data set from animal models of combat-relevant trauma, PFC, and aeromedical evacuation.

METHODS

Data from anesthetized swine (N = 30) subjected to combat relevant trauma, resuscitation, and critical care interventions were analyzed. Pairwise correlations and Bland-Altman and regression analyses were performed to compare PFR and SFR, based on averaged SpO2 values obtained from two monitoring devices.

RESULTS

We performed 683 pairwise correlations. SpO2/FiO2 ratio was numerically higher than PFR with a 313 cutoff values for acute respiratory distress syndrome (ARDS) (PFR ≥300). Sensitivity/specificity for detection of mild ARDS was 75%/73% with a 200 to 300 PFR range corresponding to 252 to 312 SFR range. For moderate ARDS, sensitivity/specificity was 61%/93% with a 100 to 200 PFR range corresponding to 191 to 251 SFR range. For severe ARDS, sensitivity/specificity was 49%/97% with a 0 to 100 PFR range corresponding to 0 to 190 SFR range. For all groups, areas under the receiver operating characteristic curves ranged from 0.76 to 0.98.

CONCLUSION

SpO2/FiO2 ratio is a useful surrogate for PFR when arterial blood gas testing is not available during dynamically changing physiologic conditions, for example, during austere conditions, PFC, or aeromedical evacuation, and may permit early detection of casualties in need of lung-specific life-saving interventions. Studies in critically ill humans are warranted.

[All Roads Lead to Rome: Results of Non-Invasive Respiratory Therapies Applied in a Tertiary-Care Hospital Without an Intermediate Care Unit During the COVID-19 Pandemic]

Introduction

Non-invasive respiratory therapies (NRT) were widely used in the first wave of the COVID-19 pandemic in different settings, depending on availability. The objective of our study was to present 90-day survival and associated factors in patients treated with NRT in a tertiary hospital without an Intermediate Respiratory Care Unit. The secondary objective was to compare the outcomes of the different therapies.

Methods

Observational study of patients treated with NRT outside of an intensive care or intermediate respiratory care unit setting, diagnosed with COVID-19 and acute respiratory distress syndrome by radiological criteria and SpO2/FiO2 ratio. A multivariate logistic regression model was developed to determine independently associated variables, and the outcomes of high flow nasal cannula and continuous positive airway pressure were compared.

Results

In total, 107 patients were treated and 85 (79.4%) survived at 90 days. Before starting NRT, the mean SpO2/FiO2 ratio was 119.8 ± 59.4. A higher SOFA score was significantly associated with mortality (OR 2,09; 95% CI 1.34-3.27), while self-pronation was a protective factor (OR 0.23; 95% CI 0.06-0.91). High flow nasal cannula was used in 63 subjects (58.9%), and continuous positive airway pressure in 41 (38.3%), with no differences between them.

Conclusion

Approximately 4 out of 5 patients treated with NRT survived to 90 days, and no significant differences were found between high flow nasal cannula and continuous positive airway pressure.

Risk factors for unplanned ICU admission after emergency department holding orders

STUDY HYPOTHESIS

Emergency department (ED) holding orders are used in an effort to streamline patient flow. Little research exists on the safety of this practice. Here, we report on prevalence and risk factors for upgrade of medical admissions to ICU for whom holding orders were written.

METHODS

Retrospective review of holding order admissions through our ED for years 2013-2018. Pregnancy, prisoner, pediatric, surgical, and ICU admissions were excluded, as were transfers from other hospitals. Risk factors of interest included vital signs, physiologic data, laboratory markers, sequential organ failure assessment (SOFA), Quick SOFA (qSOFA), modified early warning (MEWS) scores, and Charlson Comorbidity Index (CCI). Primary outcome was ICU transfer within 24 hours of admission. Analysis was completed using multivariable logistic regression.

RESULTS

Between 2013 and 2018, the ED had 203,374 visits. Approximately 20% (N = 54,915) were admitted, 23% of whom had holding orders (N = 12,680). A minority of those with a holding order were transferred to the ICU within 24 hours (N = 79; 0.62%). Those transferred to ICU had increased heart and respiratory rate, P/F ratio, and increased oxygen need. They also had higher MEWS, quick SOFA (qSOFA), and SOFA scores. Multivariable logistic regression demonstrated a significant association between ICU admission and FiO2 (odds ratio [OR] 1.47; 95% confidence interval [CI] 1.25-1.74), MEWS (OR 1.31; 95% CI 1.14-1.52), SOFA Score (OR 1.19; 95% CI 1.05-1.35), and gastrointestinal (OR 3.25; 95% CI: 1.50-7.03) or other combined diagnosis (OR 2.19; CI: 1.07-4.48) (P = 0.0017).

CONCLUSION

Holding orders are used for >20% of all admissions and <1% of those admissions required transfer to ICU within 24 hours.

Prone Position after Liberation from Prolonged Mechanical Ventilation in COVID-19 Respiratory Failure

DESIGN

This is a retrospective case series describing the feasibility and tolerability of postextubation prone positioning (PEPP) and its impact on physiologic parameters in a tertiary intensive care unit during the COVID-19 pandemic. Setting and Patients. This study was conducted on patients with COVID-19 respiratory failure hospitalized in a tertiary Intensive Care Unit at Surrey Memorial Hospital during the COVID-19 pandemic. Measurements and Results. We did not find prior reports of PEPP following prolonged intubation in the literature. Four patients underwent a total of 13 PEPP sessions following liberation from prolonged mechanical ventilation. Each patient underwent a median of 3 prone sessions (IQR: 2, 4.25) lasting a median of 1.5 hours (IQR: 1.2, 2.1). PEPP sessions were associated with a reduction in median oxygen requirements, patient respiratory rate, and reintubation rate. The sessions were well tolerated by patients, nursing, and the allied health team.

CONCLUSIONS

The novel practice of PEPP after liberation from prolonged mechanical ventilation in patients with COVID-19 respiratory failure is feasible and well tolerated, and may be associated with favourable clinical outcomes including improvement in oxygenation and respiratory rate and a low rate of reintubation. Larger prospective studies of PEPP are warranted.

Interleukin-6 receptor blocking with intravenous tocilizumab in COVID-19 severe acute respiratory distress syndrome: A retrospective case-control survival analysis of 128 patients

In cases of COVID-19 acute respiratory distress syndrome, an excessive host inflammatory response has been reported, with elevated serum interleukin-6 levels. In this multicenter retrospective cohort study we included adult patients with COVID-19, need of respiratory support, and elevated C-reactive protein who received intravenous tocilizumab in addition to standard of care. Control patients not receiving tocilizumab were matched for sex, age and respiratory support. We selected survival as the primary endpoint, along with need for invasive ventilation, thrombosis, hemorrhage, and infections as secondary endpoints at 30 days. We included 64 patients with COVID-19 in the tocilizumab group and 64 matched controls. At baseline the tocilizumab group had longer symptom duration (13 ± 5 vs. 9 ± 5 days) and received hydroxychloroquine more often than controls (100% vs. 81%). The mortality rate was similar between groups (27% with tocilizumab vs. 38%) and at multivariable analysis risk of death was not significantly influenced by tocilizumab (hazard ratio 0.61, 95% confidence interval 0.33-1.15), while being associated with the use at baseline of non invasive mechanical or invasive ventilation, and the presence of comorbidities. Among secondary outcomes, tocilizumab was associated with a lower probability of requiring invasive ventilation (hazard ratio 0.36, 95% confidence interval 0.16-0.83; P = 0.017) but not with the risk of thrombosis, bleeding, or infections. The use of intravenous tocilizumab was not associated with changes in 30-day mortality in patients with COVID-19 severe respiratory impairment. Among the secondary outcomes there was less use of invasive ventilation in the tocilizumab group.

Lung-Protective Ventilation and Associated Outcomes and Costs Among Patients Receiving Invasive Mechanical Ventilation in the ED

BACKGROUND

Invasive mechanical ventilation is often initiated in the ED, and mechanically ventilated patients may be kept in the ED for hours before ICU transfer. Although lung-protective ventilation is beneficial, particularly in ARDS, it remains uncertain how often lung-protective tidal volumes are used in the ED, and whether lung-protective ventilation in this setting impacts patient outcomes.

RESEARCH QUESTION

What is the association between the use of lung-protective ventilation in the ED and outcomes among invasively ventilated patients?

STUDY DESIGN AND METHODS

A retrospective analysis (2011-2017) of a prospective registry from eight EDs enrolling consecutive adult patients (≥ 18 years) who received invasive mechanical ventilation in the ED was performed. Lung-protective ventilation was defined by use of tidal volumes ≤ 8 mL/kg predicted body weight. The primary outcome was hospital mortality. Secondary outcomes included development of ARDS, hospital length of stay, and total hospital costs.

RESULTS

The study included 4,174 patients, of whom 2,437 (58.4%) received lung-protective ventilation in the ED. Use of lung-protective ventilation was associated with decreased odds of hospital death (adjusted OR [aOR], 0.91; 95% CI, 0.84-0.96) and development of ARDS (aOR, 0.87; 95% CI, 0.81-0.92). Patients who received lung-protective ventilation in the ED had shorter median duration of mechanical ventilation (4 vs 5 days; P < 0.01), shorter median hospital length of stay (11 vs 14 days; P < .001), and reduced total hospital costs (Can$44,348 vs Can$52,484 [US$34,153 vs US$40,418]; P = .03) compared with patients who received higher tidal volumes.

INTERPRETATION

Use of lung-protective ventilation in the ED was associated with important patient- and system-centered outcomes, including lower hospital mortality, decreased incidence of ARDS, lower hospital length of stay, and decreased total costs. Protocol development promoting the regular use of lung-protective ventilation in the ED may be of value.

Auxora versus standard of care for the treatment of severe or critical COVID-19 pneumonia: results from a randomized controlled trial

BACKGROUND

Calcium release-activated calcium (CRAC) channel inhibitors stabilize the pulmonary endothelium and block proinflammatory cytokine release, potentially mitigating respiratory complications observed in patients with COVID-19. This study aimed to investigate the safety and efficacy of Auxora, a novel, intravenously administered CRAC channel inhibitor, in adults with severe or critical COVID-19 pneumonia.

METHODS

A randomized, controlled, open-label study of Auxora was conducted in adults with severe or critical COVID-19 pneumonia. Patients were randomized 2:1 to receive three doses of once-daily Auxora versus standard of care (SOC) alone. The primary objective was to assess the safety and tolerability of Auxora. Following FDA guidance, study enrollment was halted early to allow for transition to a randomized, blinded, placebo-controlled study.

RESULTS

In total, 17 patients with severe and three with critical COVID-19 pneumonia were randomized to Auxora and nine with severe and one with critical COVID-19 pneumonia to SOC. Similar proportions of patients receiving Auxora and SOC experienced ≥ 1 adverse event (75% versus 80%, respectively). Fewer patients receiving Auxora experienced serious adverse events versus SOC (30% versus 50%, respectively). Two patients (10%) receiving Auxora and two (20%) receiving SOC died during the 30 days after randomization. Among patients with severe COVID-19 pneumonia, the median time to recovery with Auxora was 5 days versus 12 days with SOC; the recovery rate ratio was 1.87 (95% CI, 0.72, 4.89). Invasive mechanical ventilation was needed in 18% of patients with severe COVID-19 pneumonia receiving Auxora versus 50% receiving SOC (absolute risk reduction = 32%; 95% CI, - 0.07, 0.71). Outcomes measured by an 8-point ordinal scale were significantly improved for patients receiving Auxora, especially for patients with a baseline PaO2/FiO2 = 101-200.

CONCLUSIONS

Auxora demonstrated a favorable safety profile in patients with severe or critical COVID-19 pneumonia and improved outcomes in patients with severe COVID-19 pneumonia. These results, however, are limited by the open-label study design and small patient population resulting from the early cessation of enrollment in response to regulatory guidance. The impact of Auxora on respiratory complications in patients with severe COVID-19 pneumonia will be further assessed in a planned randomized, blinded, placebo-controlled study.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04345614 . Submitted on 7 April 2020.

Observational Study of Hydroxychloroquine in Hospitalized Patients with Covid-19

BACKGROUND

Hydroxychloroquine has been widely administered to patients with Covid-19 without robust evidence supporting its use.

METHODS

We examined the association between hydroxychloroquine use and intubation or death at a large medical center in New York City. Data were obtained regarding consecutive patients hospitalized with Covid-19, excluding those who were intubated, died, or discharged within 24 hours after presentation to the emergency department (study baseline). The primary end point was a composite of intubation or death in a time-to-event analysis. We compared outcomes in patients who received hydroxychloroquine with those in patients who did not, using a multivariable Cox model with inverse probability weighting according to the propensity score.

RESULTS

Of 1446 consecutive patients, 70 patients were intubated, died, or discharged within 24 hours after presentation and were excluded from the analysis. Of the remaining 1376 patients, during a median follow-up of 22.5 days, 811 (58.9%) received hydroxychloroquine (600 mg twice on day 1, then 400 mg daily for a median of 5 days); 45.8% of the patients were treated within 24 hours after presentation to the emergency department, and 85.9% within 48 hours. Hydroxychloroquine-treated patients were more severely ill at baseline than those who did not receive hydroxychloroquine (median ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen, 223 vs. 360). Overall, 346 patients (25.1%) had a primary end-point event (180 patients were intubated, of whom 66 subsequently died, and 166 died without intubation). In the main analysis, there was no significant association between hydroxychloroquine use and intubation or death (hazard ratio, 1.04, 95% confidence interval, 0.82 to 1.32). Results were similar in multiple sensitivity analyses.

CONCLUSIONS

In this observational study involving patients with Covid-19 who had been admitted to the hospital, hydroxychloroquine administration was not associated with either a greatly lowered or an increased risk of the composite end point of intubation or death. Randomized, controlled trials of hydroxychloroquine in patients with Covid-19 are needed. (Funded by the National Institutes of Health.).

The Effect of Imputation of PaO2/FIO2 From SpO2/FIO2 on the Performance of the Pediatric Index of Mortality 3

OBJECTIVES

To investigate if the performance of Pediatric Index of Mortality 3 is improved by including imputed values for the PaO2/FIO2 ratio where measurements of PaO2 or FIO2 are missing.

DESIGN

A prospective observational study.

SETTING

A bi-national pediatric intensive care registry.

PATIENTS

The records of 37,983 admissions of children less than 16 years old admitted to 19 ICUs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Seven published equations describing an association between PaO2/FIO2 and oxygen saturation measured by pulse oximetry (SpO2)/FIO2 were used to derive an alternative variable d100 × FIO2/PaO2 for the Pediatric Index of Mortality 3 variable 100 × FIO2/PaO2. Six equations exclude SpO2/FIO2 values if SpO2 is greater than 96-98%. 100 × FIO2/PaO2 was missing in 72% of patient records primarily due to missing PaO2, d100 × FIO2/PaO2 was missing in 71% of patient records if values of SpO2greater than 97% were excluded or in 17% of patient records if all measurements of SpO2 were included. Univariable analysis supported the inclusion of SpO2 values greater than 97%. Compared to the standard Pediatric Index of Mortality 3 model, two alternative models imputing 100 × FIO2/PaO2 from d100 × FIO2/PaO2 only if 100 × FIO2/PaO2 was missing, or using d100 × FIO2/PaO2 values exclusively, resulted in a small but statistically significant improvements in discrimination of Pediatric Index of Mortality 3 (area under the receiver operator curve 0.9068 [0. 8965-0. 9171]; 0.9083 [0.8981-0.9184]; 0.9087 [0.8987-0.9188], respectively).

CONCLUSIONS

Imputation of the PaO2/FIO2 ratio in cases where arterial sampling was not performed resulted in a large reduction in the rate of missing data if all values of SpO2 were included. The imputation technique improved the discrimination of Pediatric Index of Mortality 3; however, the magnitude of the increment in overall model performance was small. A possible benefit of the approach is reducing the potential for bias resulting from variation in practice for invasive monitoring of oxygenation.

A new method for identifying the acute respiratory distress syndrome disease based on noninvasive physiological parameters

Early diagnosis and prevention play a crucial role in the treatment of patients with ARDS. The definition of ARDS requires an arterial blood gas to define the ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO₂/FiO₂ ratio). However, many patients with ARDS do not have a blood gas measured, which may result in under-diagnosis of the condition. Using data from MIMIC-III Database, we propose an algorithm based on patient non-invasive physiological parameters to estimate P/F levels to aid in the diagnosis of ARDS disease. The machine learning algorithm was combined with the filter feature selection method to study the correlation of various noninvasive parameters from patients to identify the ARDS disease. Cross-validation techniques are used to verify the performance of algorithms for different feature subsets. XGBoost using the optimal feature subset had the best performance of ARDS identification with the sensitivity of 84.03%, the specificity of 87.75% and the AUC of 0.9128. For the four machine learning algorithms, reducing a certain number of features, AUC can still above 0.8. Compared to Rice Linear Model, this method has the advantages of high reliability and continually monitoring the development of patients with ARDS.

Association Between Peripheral Blood Oxygen Saturation (SpO2)/Fraction of Inspired Oxygen (FiO2) Ratio Time at Risk and Hospital Mortality in Mechanically Ventilated Patients

INTRODUCTION

Acute respiratory failure requiring mechanical ventilation is a leading cause of mortality in the intensive care unit. Although single peripheral blood oxygen saturation/fraction of inspired oxygen (SpO2/FiO2) ratios of hypoxemia have been evaluated to risk-stratify patients with acute respiratory distress syndrome, the utility of longitudinal SpO2/FiO2 ratios is unknown.

OBJECTIVE

To assess time-based SpO2/FiO2 ratios ≤ 150-SpO2/FiO2 time at risk (SF-TAR)-for predicting mortality in mechanically ventilated patients.

METHODS

Retrospective, observational cohort study of mechanically ventilated patients at 21 community and 2 academic hospitals. Association between the SF-TAR in the first 24 hours of ventilation and mortality was examined using multivariable logistic regression and compared with the worst recorded isolated partial pressure of arterial oxygen/fraction of inspired oxygen (P/F) ratio.

RESULTS

In 28,758 derivation cohort admissions, every 10% increase in SF-TAR was associated with a 24% increase in adjusted odds of hospital mortality (adjusted odds ratio = 1.24; 95% confidence interval [CI] = 1.23-1.26); a similar association was observed in validation cohorts. Discrimination for mortality modestly improved with SF-TAR (area under the receiver operating characteristic curve [AUROC] = 0.81; 95% CI = 0.81-0.82) vs the worst P/F ratio (AUROC = 0.78; 95% CI = 0.78-0.79) and worst SpO2/FiO2 ratio (AUROC = 0.79; 95% CI = 0.79-0.80). The SF-TAR in the first 6 hours offered comparable discrimination for hospital mortality (AUROC = 0.80; 95% CI = 0.79-0.80) to the 24-hour SF-TAR.

CONCLUSION

The SF-TAR can identify ventilated patients at increased risk of death, offering modest improvements compared with single SpO2/FiO2 and P/F ratios. This longitudinal, noninvasive, and broadly generalizable tool may have particular utility for early phenotyping and risk stratification using electronic health record data in ventilated patients.

Pulmonary Thrombosis or Embolism in a Large Cohort of Hospitalized Patients With Covid-19

Objective: We set out to analyze the incidence and predictive factors of pulmonary embolism (PE) in hospitalized patients with Covid-19. Methods: We prospectively collected data from all consecutive patients with laboratory-confirmed Covid-19 admitted to the Hospital de la Santa Creu i Sant Pau, a university hospital in Barcelona, between March 9 and April 15, 2020. Patients with suspected PE, according to standardized guidelines, underwent CT pulmonary angiography (CTPA). Results: A total of 1,275 patients with Covid-19 were admitted to hospital. CTPA was performed on 76 inpatients, and a diagnosis of PE was made in 32 (2.6% [95%CI 1.7-3.5%]). Patients with PE were older, and they exhibited lower PaO₂:FiO₂ ratios and higher levels of D-dimer and C-reactive protein (CRP). They more often required admission to ICU and mechanical ventilation, and they often had longer hospital stays, although in-hospital mortality was no greater than in patients without PE. High CRP and D-dimer levels at admission (≥150 mg/L and ≥1,000 ng/ml, respectively) and a peak D-dimer ≥6,000 ng/ml during hospital stay were independent factors associated with PE. Prophylactic low molecular weight heparin did not appear to prevent PE. Increased CRP levels correlated with increased D-dimer levels and both correlated with a lower PaO₂:FiO₂. Conclusions: The 2.6% incidence of PE in Covid-19 hospitalized patients is clearly high. Higher doses of thromboprophylaxis may be required to prevent PE, particularly in patients at increased risk, such as those with high levels of CRP and D-dimer at admission. These findings should be validated in future studies.

Imputation of partial pressures of arterial oxygen using oximetry and its impact on sepsis diagnosis

OBJECTIVE

The ratio of the partial pressure of arterial oxygen to fraction of inspired oxygen is a key component of the sequential organ failure assessment score that operationally defines sepsis. But, it is calculated infrequently due to the need for the acquisition of an arterial blood gas. So, we sought to find an optimal imputation strategy for the estimation of sepsis-defining hypoxemic respiratory failure using oximetry instead of an arterial blood gas.

APPROACH

We retrospectively studied a sample of non-intubated acute-care patients with oxygen saturation recorded  ⩽10 min before arterial blood sampling (N  =  492 from 2013-2017). We imputed ratios of the partial pressure of arterial oxygen to the fraction of inspired oxygen and sepsis criteria from existing imputation equations (Hill, Severinghaus-Ellis, Rice, and Pandharipande) and compared them with the ratios and sepsis criteria measured from arterial blood gases. We devised a modified model-based equation to eliminate the bias of the results.

MAIN RESULTS

Hypoxemia severity estimates from the Severinghaus-Ellis equation were more accurate than those from other existing equations, but showed significant proportional bias towards under-estimation of hypoxemia severity, especially at oxygen saturations  >96%. Our modified equation eliminated bias and surpassed others on all imputation quality metrics.

SIGNIFICANCE

Our modified imputation equation, [Formula: see text] is the first one that is free of bias at all oxygen saturations. It resulted in ratios of partial pressure of arterial oxygen to fraction of inspired oxygen and sepsis respiratory criteria closest to those obtained by arterial blood gas testing and is the optimal imputation strategy for non-intubated acute-care patients.

Evaluating Delivery of Low Tidal Volume Ventilation in Six ICUs Using Electronic Health Record Data

OBJECTIVES

Mechanical ventilation with low tidal volumes is recommended for all patients with acute respiratory distress syndrome and may be beneficial to other intubated patients, yet consistent implementation remains difficult to obtain. Using detailed electronic health record data, we examined patterns of tidal volume administration, the effect on clinical outcomes, and alternate metrics for evaluating low tidal volume compliance in clinical practice.

DESIGN

Observational cohort study.

SETTING

Six ICUs in a single hospital system.

PATIENTS

Adult patients who received invasive mechanical ventilation more than 12 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Tidal volumes were analyzed across 1,905 hospitalizations. Although mean tidal volume was 6.8 mL/kg predicted body weight, 40% of patients were exposed to tidal volumes greater than 8 mL/kg predicted body weight, with 11% for more than 24 hours. At a patient level, exposure to 24 total hours of tidal volumes greater than 8 mL/kg predicted body weight was associated with increased mortality (odds ratio, 1.82; 95% CI, 1.20-2.78), whereas mean tidal volume exposure was not (odds ratio, 0.87/1 mL/kg increase; 95% CI, 0.74-1.02). Initial tidal volume settings strongly predicted exposure to volumes greater than 8 mL/kg for 24 hours; the adjusted rate was 21.5% when initial volumes were greater than 8 mL/kg predicted body weight and 7.1% when initial volumes were less than 8 mL/kg predicted body weight. Across ICUs, correlation of mean tidal volume with alternative measures of low tidal volume delivery ranged from 0.38 to 0.66.

CONCLUSIONS

Despite low mean tidal volume in the cohort, a significant percentage of patients were exposed to a prolonged duration of high tidal volumes which was correlated with higher mortality. Detailed ventilator records in the electronic health record provide a unique window for evaluating low tidal volume delivery and targets for improvement.

Prospective Observational Study Comparing Sepsis-2 and Sepsis-3 Definitions in Predicting Mortality in Critically Ill Patients

Background

Sepsis definitions have evolved, but there is a lack of consensus over adoption of the most recent definition, Sepsis-3. We sought to compare Sepsis-2 and Sepsis-3 in the classification of patients with sepsis and mortality risk at 30 days.

Methods

We used the following definitions: Sepsis-2 (≥2 systemic inflammatory response syndrome criteria + infection), Sepsis-3 (prescreening by quick Sequential Organ Failure Assessment [qSOFA] of ≥2 of 3 criteria followed by the complete score change ≥2 + infection), and an amended Sepsis-3 definition, iqSOFA (qSOFA ≥2 + infection). We used χ ² or Wilcoxon rank-sum tests, receiver-operator characteristic curves, and survival analysis.

Results

We enrolled 176 patients (95% in an intensive care unit, 38.6% female, median age 61.4 years). Of 105 patients classified by Sepsis-2 as having sepsis, 80 had sepsis per Sepsis-3 or iqSOFA (kappa = 0.72; 95% confidence interval [CI], 0.62–0.82). Twenty-five (14.8%) died (20 of 100 with sepsis per Sepsis-2 [20%], and 20 of 77 [26.0%] with sepsis per Sepsis-3 or iqSOFA). Results for Sepsis-3 and iqSOFA were identical. The area under the curve of receiver-operator characteristic (ROC) curves for identifying those who died were 0.54 (95% CI, 0.41–0.68) for Sepsis-2, 0.84 (95% CI, 0.74–0.93) for Sepsis-3, and 0.69 (95% CI, 0.60–0.79) for iqSOFA (P < .01). Hazard ratios for death associated with sepsis were greatest for sepsis or septic shock per Sepsis-3.

Conclusions

Sepsis-3 and iqSOFA were better at predicting death than Sepsis-2. Using the SOFA score might add little advantage compared with the simpler iqSOFA score.

Acute Respiratory Distress in the Operating Room and Prone Ventilation: A Case Report

There have been many advances in the management of acute respiratory distress syndrome, a condition which Bellani et al, in the LUNG SAFE trial (Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure), found represents up to 10.4% of intensive care unit admissions and 23.4% of patients requiring mechanical ventilation, with an unadjusted intensive care unit and hospital mortality of 35.3% and 40%, respectively. Studies have shown that prone positioning can improve oxygenation in patients who are mechanically ventilated for acute respiratory distress syndrome. This case report describes an example in which intraoperative prone positioning improved oxygenation in a patient after aspiration of gastric contents on induction of general anesthesia.

Early Neuromuscular Blockade in the Acute Respiratory Distress Syndrome

BACKGROUND

The benefits of early continuous neuromuscular blockade in patients with acute respiratory distress syndrome (ARDS) who are receiving mechanical ventilation remain unclear.

METHODS

We randomly assigned patients with moderate-to-severe ARDS (defined by a ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen of <150 mm Hg with a positive end-expiratory pressure [PEEP] of ≥8 cm of water) to a 48-hour continuous infusion of cisatracurium with concomitant deep sedation (intervention group) or to a usual-care approach without routine neuromuscular blockade and with lighter sedation targets (control group). The same mechanical-ventilation strategies were used in both groups, including a strategy involving a high PEEP. The primary end point was in-hospital death from any cause at 90 days.

RESULTS

The trial was stopped at the second interim analysis for futility. We enrolled 1006 patients early after the onset of moderate-to-severe ARDS (median, 7.6 hours after onset). During the first 48 hours after randomization, 488 of the 501 patients (97.4%) in the intervention group started a continuous infusion of cisatracurium (median duration of infusion, 47.8 hours; median dose, 1807 mg), and 86 of the 505 patients (17.0%) in the control group received a neuromuscular blocking agent (median dose, 38 mg). At 90 days, 213 patients (42.5%) in the intervention group and 216 (42.8%) in the control group had died before hospital discharge (between-group difference, -0.3 percentage points; 95% confidence interval, -6.4 to 5.9; P = 0.93). While in the hospital, patients in the intervention group were less physically active and had more adverse cardiovascular events than patients in the control group. There were no consistent between-group differences in end points assessed at 3, 6, and 12 months.

CONCLUSIONS

Among patients with moderate-to-severe ARDS who were treated with a strategy involving a high PEEP, there was no significant difference in mortality at 90 days between patients who received an early and continuous cisatracurium infusion and those who were treated with a usual-care approach with lighter sedation targets. (Funded by the National Heart, Lung, and Blood Institute; ROSE ClinicalTrials.gov number, NCT02509078.).

A phase I trial of low-dose inhaled carbon monoxide in sepsis-induced ARDS

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a prevalent disease with significant mortality for which no effective pharmacologic therapy exists. Low-dose inhaled carbon monoxide (iCO) confers cytoprotection in preclinical models of sepsis and ARDS.

METHODS

We conducted a phase I dose escalation trial to assess feasibility and safety of low-dose iCO administration in patients with sepsis-induced ARDS. Twelve participants were randomized to iCO or placebo air 2:1 in two cohorts. Four subjects each were administered iCO (100 ppm in cohort 1 or 200 ppm in cohort 2) or placebo for 90 minutes for up to 5 consecutive days. Primary outcomes included the incidence of carboxyhemoglobin (COHb) level ≥10%, prespecified administration-associated adverse events (AEs), and severe adverse events (SAEs). Secondary endpoints included the accuracy of the Coburn-Forster-Kane (CFK) equation to predict COHb levels, biomarker levels, and clinical outcomes.

RESULTS

No participants exceeded a COHb level of 10%, and there were no administration-associated AEs or study-related SAEs. CO-treated participants had a significant increase in COHb (3.48% ± 0.7% [cohort 1]; 4.9% ± 0.28% [cohort 2]) compared with placebo-treated subjects (1.97% ± 0.39%). The CFK equation was highly accurate at predicting COHb levels, particularly in cohort 2 (R2 = 0.9205; P < 0.0001). Circulating mitochondrial DNA levels were reduced in iCO-treated participants compared with placebo-treated subjects.

CONCLUSION

Precise administration of low-dose iCO is feasible, well-tolerated, and appears to be safe in patients with sepsis-induced ARDS. Excellent agreement between predicted and observed COHb should ensure that COHb levels remain in the target range during future efficacy trials.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02425579.

FUNDING

NIH grants P01HL108801, KL2TR002385, K08HL130557, and K08GM102695.

Respiratory failure requiring mechanical ventilation in critically ill adults in Ghana: A prospective observational study

INTRODUCTION

Respiratory failure is commonly seen in African emergency centres and intensive care units, but little is known about the need for intubation and mechanical ventilation.

METHODS

From April to October 2017, we recorded the number of patients intubated and ventilated in the emergency centre and intensive care unit at Komfo Anokye Teaching Hospital in Kumasi, Ghana on a daily basis. We assessed patients for presence of acute respiratory distress syndrome (ARDS) using the Kigali Modification of the Berlin ARDS criteria. ARDS patients were re-assessed daily.

RESULTS

During the study period, 102 patients were intubated, of which 82 were assessed by the study team. The remaining 20 patients died before they could be assessed. Two (2.4%) patients were identified as having ARDS, and both died. Neither was treated with prone positioning or chemical paralysis. It is possible that many of the patients who died before an assessment suffered from ARDS, considering its associated high mortality, and thus the true incidence of ARDS may have been higher.

CONCLUSION

Respiratory failure requiring intubation and mechanical ventilation is common in patients presenting to the emergency centre or intensive care unit at an academic tertiary care centre in Ghana. The true incidence of ARDS was likely underestimated by our study.

Rapidly Improving ARDS in Therapeutic Randomized Controlled Trials

BACKGROUND

Observational studies suggest that some patients meeting criteria for ARDS no longer fulfill the oxygenation criterion early in the course of their illness. This subphenotype of rapidly improving ARDS has not been well characterized. We attempted to assess the prevalence, characteristics, and outcomes of rapidly improving ARDS and to identify which variables are useful to predict it.

METHODS

A secondary analysis was performed of patient level data from six ARDS Network randomized controlled trials. We defined rapidly improving ARDS, contrasted with ARDS > 1 day, as extubation or a Pao₂ to Fio₂ ratio (Pao₂:Fio₂) > 300 on the first study day following enrollment.

RESULTS

The prevalence of rapidly improving ARDS was 10.5% (458 of 4,361 patients) and increased over time. Of the 1,909 patients enrolled in the three most recently published trials, 197 (10.3%) were extubated on the first study day, and 265 (13.9%) in total had rapidly improving ARDS. Patients with rapidly improving ARDS had lower baseline severity of illness and lower 60-day mortality (10.2% vs 26.3%; P < .0001) than ARDS > 1 day. Pao₂:Fio₂ at screening, change in Pao₂:Fio₂ from screening to enrollment, use of vasopressor agents, Fio₂ at enrollment, and serum bilirubin levels were useful predictive variables.

CONCLUSIONS

Rapidly improving ARDS, mostly defined by early extubation, is an increasingly prevalent and distinct subphenotype, associated with better outcomes than ARDS > 1 day. Enrollment of patients with rapidly improving ARDS may negatively affect the prognostic enrichment and contribute to the failure of therapeutic trials.

The Value of Oxygenation Saturation Index in Predicting the Outcomes of Patients with Acute Respiratory Distress Syndrome

This study aims to investigate the association between oxygenation saturation index (OSI) and the outcome of acute respiratory distress syndrome (ARDS) patients, and assess the predictive performance of OSI for ARDS patients’ mortality. This study was conducted at one regional hospital with 66 adult intensive care unit (ICU) beds. All patients with ARDS were identified between November 1 2016 and May 31 2018, and their clinical information was retrospectively collected. The lowest PaO₂/FiO₂ ratio and SpO₂/FiO₂ ratio and highest mean airway pressure (MAP) were recorded on the first day of ARDS; and oxygen index (OI) and OSI were calculated as (FiO₂ × MAP × 100)/PaO₂, and (FiO₂ × MAP × 100) /SpO₂ accordingly. During the study period, a total of 101 patients with ARDS were enrolled, and their mean age was 69.2 years. The overall in-ICU and in-hospital mortality rate was 57.4% and 61.4%, respectively. The patients with in-ICU mortality had higher APACHE II score than the survivors (31.6 ± 9.8 vs. 23.0 ± 9.1, p < 0.001). In addition, mortalities had lower SpO₂, and SpO₂/FiO₂ ratios than the survivors (both p < 0.05). In contrast, survivors had lower OI, and OSI than the mortalities (both p = 0.008). Both OSI (area under curve (AUC) = 0.656, p = 0.008) and OI (AUC = 0.654, p = 0.008) had good predictive performance of mortality among ARDS patients using receiver-operating characteristics (ROC) curves analysis. In addition, the AUC of SpO₂/FiO₂ (AUC = 0.616, p = 0.046) had better performance for mortality prediction than PaO₂/FiO₂ (AUC = 0.603, p = 0.08). The patients with OSI greater than 12 had a higher risk of mortality than OSI < 12 (adjusted OR, 5.22, 95% CI, 1.31–20.76, p = 0.019). In contrast, OI, PaO₂/FiO₂, and SpO₂/FiO₂ were not found to be significantly associated with increased mortality. OSI is significantly associated with the increased mortality of ARDS patients and can also be a good outcome predictor.

Late organ failures in patients with prolonged intensive care unit stays

PURPOSE

The purpose of this study was to characterize the organ failures that develop among patients with prolonged ICU stays, defined as those who spent a minimum of 14 days in an ICU.

METHODS

We retrospectively studied a cohort of consecutive patients from a university hospital who were in an ICU for a minimum of 14 days during 2014-2016. We calculated daily Sequential Organ Failure Assessment (SOFA) scores from admission to ICU day 14. The primary outcome was the number of new late organ failures, defined as occurring on ICU day 4 through 14.

RESULTS

In a retrospective cohort of 3777 consecutive patients in six ICUs, 50 patients had prolonged ICU stays. Of those 50, new cardiovascular failure occurred in 24 (62%) on day 4 or later; persistent mechanical ventilation was present in only 28 (56%).

CONCLUSIONS

Strategies aiming to reduce the development of new late organ failures may be a novel target for preventing persistent critical illness.

Duration of acute kidney injury in critically ill patients

Background

Duration of acute kidney injury (AKI) has been recognized a risk factor for adverse outcomes following AKI. We sought to examine the relationship of AKI duration and recurrent AKI with short-term outcomes in critically ill patients who were mechanically ventilated and met criteria for the acute respiratory distress syndrome.

Methods

Participants in the NHLBI ARDS Network SAILS multicenter trial who developed AKI were included in this analysis and divided into groups based on AKI duration. Differences in outcomes were evaluated using t test and Chi-square test. Competing risks regression and Cox regression were used to evaluate factors associated with resolving AKI and recurrent AKI.

Results

In total, 238 patients were included in the study. Seventy-seven patients had short duration AKI (1–2 days), 47 medium duration AKI (3–7 days), 87 persistent AKI (> 7 days) and 38 died during their AKI episode. Persistent AKI was associated with worse outcomes including increased ICU length of stay, time on the ventilator and days with cardiovascular failure. We found no clinical differences between patients with short and medium duration AKI, even when accounting for AKI severity and recurrent AKI. Patients with resolving AKI were less likely to have oliguria or moderate/severe ARDS on the day AKI criteria were met. Recurrent AKI was associated with poorer clinical outcomes. No baseline clinical factors were found to predict development of recurrent AKI.

Conclusions

In critically ill patients with sepsis-associated ARDS and AKI, the impact of short and medium duration AKI on clinical outcomes was modest. Persistent and recurrent AKI were both associated with worse clinical outcomes, emphasizing the importance of identifying these patients, who may benefit from novel interventions.

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0374-x) contains supplementary material, which is available to authorized users.

Utility of SOFA score, management and outcomes of sepsis in Southeast Asia: a multinational multicenter prospective observational study

BACKGROUND

Sepsis is a global threat but insufficiently studied in Southeast Asia. The objective was to evaluate management, outcomes, adherence to sepsis bundles, and mortality prediction of maximum Sequential Organ Failure Assessment (SOFA) scores in patients with community-acquired sepsis in Southeast Asia.

METHODS

We prospectively recruited hospitalized adults within 24 h of admission with community-acquired infection at nine public hospitals in Indonesia (n = 3), Thailand (n = 3), and Vietnam (n = 3). In patients with organ dysfunction (total SOFA score ≥ 2), we analyzed sepsis management and outcomes and evaluated mortality prediction of the SOFA scores. Organ failure was defined as the maximum SOFA score ≥ 3 for an individual organ system.

RESULTS

From December 2013 to December 2015, 454 adult patients presenting with community-acquired sepsis due to diverse etiologies were enrolled. Compliance with sepsis bundles within 24 h of admission was low: broad-spectrum antibiotics in 76% (344/454), ≥ 1500 mL fluid in 50% of patients with hypotension or lactate ≥ 4 mmol/L (115/231), and adrenergic agents in 71% of patients with hypotension (135/191). Three hundred and fifty-five patients (78%) were managed outside of ICUs. Ninety-nine patients (22%) died. Total SOFA score on admission of those who subsequently died was significantly higher than that of those who survived (6.7 vs. 4.6, p < 0.001). The number of organ failures showed a significant correlation with 28-day mortality, which ranged from 7% in patients without any organ failure to 47% in those with failure of at least four organs (p < 0.001). The area under the receiver operating characteristic curve of the total SOFA score for discrimination of mortality was 0.68 (95% CI 0.62-0.74).

CONCLUSIONS

Community-acquired sepsis in Southeast Asia due to a variety of pathogens is usually managed outside the ICU and with poor compliance to sepsis bundles. In this population, calculation of SOFA scores is feasible and SOFA scores are associated with mortality.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02157259. Registered 5 June 2014, retrospectively registered.