Prognostic values of the Berlin definition criteria, blood lactate level, and fibroproliferative changes on high-resolution computed tomography in ARDS patients

Prognostic significance of lactate/albumin ratio in respiratory failure and sepsis

INTRODUCTION

Prognostic markers like SOFA and APACHE-II scores for sepsis and acute respiratory failure (ARF) are often complex for routine use. This study evaluated the lactate-albumin ratio (LAR) as a prognostic marker for in-hospital outcomes, mechanical ventilation, and inotrope requirement.

METHODS

A prospective cohort study was conducted among ICU and Internal Medicine Unit patients at Manipal Teaching Hospital, approved by the Institutional Review Committee (approval number IRC/MCOMS/584). Arterial samples for ABG values (lactate, PaO2, PaCO2, HCO3, and FiO2) and venous samples for albumin, bilirubin and creatinine were collected on admission. Arterial lactate, serum albumin, LAR and SOFA scores were recorded and compared with in-hospital outcomes. Statistical analyses were performed using SPSS version 25, with ROC-AUC for assessing prognostic markers (LAR, lactate alone) and Delong's test for comparison.

RESULT

Among 115 sepsis cases, ROC-AUC of LAR for in-hospital mortality (cut-off 1.78), mechanical ventilation (1.28), and inotropes (1.07) were 0.914, 0.881, and 0.819, respectively. Among 99 ARF cases, ROC-AUC for mortality (1.98), ventilation (1.10), and inotropes (1.18) were 0.878, 0.958, and 0.876. Among 43 sepsis + ARF cases, ROC-AUC for mortality (2.14), ventilation (1.20), and inotropes (1.20) were 0.853, 0.874, and 0.849.

CONCLUSION

The lactate-albumin ratio was a better prognostic marker than albumin alone and SOFA score for predicting in-hospital mortality, need for mechanical ventilation and inotropes in sepsis, ARF and combined Sepsis and ARF patients whereas it was statistically equivalent to lactate alone in predicting in hospital outcome. Lactate-albumin ratio also indicated disease progression, where an increase in cut-off value was seen with progressed or severe disease.

Impact of low dose inhaled nitric oxide treatment in spontaneously breathing and intubated COVID-19 patients: a retrospective propensity-matched study

BACKGROUND

The benefit of Inhaled nitric oxide (iNO) therapy in the setting of COVID-19-related ARDS is obscure. We performed a multicenter retrospective study to evaluate the impact of iNO on patients with COVID-19 who require respiratory support.

METHODS

This retrospective multicenter study included COVID-19 patients enrolled in the SCCM VIRUS COVID-19 registry who were admitted to different Mayo Clinic sites between March 2020 and June 2022 and required high-flow nasal cannula (HFNC), non-invasive ventilation (NIV), or invasive mechanical ventilation (IMV). Patients were included in the 'spontaneously breathing' group if they remained non-intubated or were initiated on an HFNC (± NIV) before intubation. Patients who got intubated without prior use of an HFNC (± NIV) were included in the 'intubated group.' They were further divided into categories based on their iNO usage. Propensity score matching (PSM) and inverse propensity of treatment weighting (IPTW) were performed to examine outcomes.

RESULTS

Among 2767 patients included in our analysis, 1879 belonged to spontaneously breathing (153 received iNO), and 888 belonged to the intubated group (193 received iNO). There was a consistent improvement in FiO2 requirement, P/F ratio, and respiratory rate within 48 h of iNO use among both spontaneously breathing and intubated groups. However, there was no significant difference in intubation risk with iNO use among spontaneously breathing patients (PSM OR 1.08, CI 0.71-1.65; IPTW OR 1.10, CI 0.90-1.33). In a time-to-event analysis using Cox proportional hazard model, spontaneously breathing patients initiated on iNO had a lower hazard ratio of in-hospital mortality (PSM HR 0.49, CI 0.32-0.75, IPTW HR 0.40, 95% CI 0.26-0.62) but intubated patients did not (PSM HR: 0.90; CI 0.66-1.24, IPTW HR 0.98, 95% CI 0.73-1.31). iNO use was associated with longer in-hospital stays, ICU stays, ventilation duration, and a higher incidence of creatinine rise.

CONCLUSIONS

This retrospective propensity-score matched study showed that spontaneously breathing COVID-19 patients on HFNC/ NIV support had a decreased in-hospital mortality risk with iNO use in a time-to-event analysis. Both intubated and spontaneously breathing patients had improvement in oxygenation parameters with iNO therapy but were associated with longer in-hospital stays, ICU stays, ventilation duration, and higher incidence of creatinine rise.

Serum β2-microglobulin as an independent risk factor for mortality in patients with acute respiratory distress syndrome caused by bacterial infection

Acute respiratory distress syndrome (ARDS) is a heterogeneous disease with extremely high mortality. We hypothesized that the serum β2-microglobulin (β2MG) level would be elevated and be an independent risk factor for 28-day mortality in patients with ARDS caused by bacterial infection. We retrospectively enrolled 257 patients with ARDS caused by bacterial infection from January 1, 2015 to February 28, 2021. Patients were followed for up to 28 days and were divided into a survival group and non-survival group according to their clinical outcomes. The serum β2MG levels and other clinical data were collected. The relationship between β2MG levels and 28-day mortality was explored by performing a Cox regression analysis adjusted for age, updated Charlson comorbidity index, disorders of consciousness, septic shock, albumin level, cardiac troponin I level, procalcitonin level, lactic acid level, prothrombin time, partial pressure of arterial oxygen/fraction of inspired oxygen ratio, estimated glomerular filtration rate and Sequential Organ Failure Assessment. In this cohort, 96 patients died in 28 days, yielding a 28-day mortality of 37.4%. The median level of serum β2MG for all enrolled patients was 4.7 (interquartile range [IQR]: 2.9-8.5) mg/L. Higher β2MG levels were significantly associated with 28-day mortality when the β2MG level was analysed as a continuous variable (hazard ratio [HR]: 1.053; 95% confidence interval [CI] 1.004-1.104; P = 0.032) and when it was categorized into tertiles (HR: 3.241; 95% CI 1.180-8.905; P = 0.023). The β2MG level exhibited a high diagnostic accuracy for predicting 28-day mortality (area under the curve [AUC] = 0.732; 95% CI 0.673-0.785; sensitivity: 74.0%; specificity: 64.0%; P < 0.001). The level of serum β2MG is elevated and is an independent risk factor of 28-day mortality in patients with ARDS caused by bacterial infection.

Chest CT findings in severe acute respiratory distress syndrome requiring V-V ECMO: J-CARVE registry

BACKGROUND

Chest computed tomography findings are helpful for understanding the pathophysiology of severe acute respiratory distress syndrome (ARDS). However, there is no large, multicenter, chest computed tomography registry for patients requiring veno-venous extracorporeal membrane oxygenation (V-V ECMO). The aim of this study was to describe chest computed tomography findings at V-V ECMO initiation and to evaluate the association between the findings and outcomes in severe ARDS.

METHODS

This multicenter, retrospective cohort study enrolled patients with severe ARDS on V-V ECMO, who were admitted to the intensive care units of 24 hospitals in Japan between January 1, 2012, and December 31, 2022.

RESULTS

The primary outcome was 90-day in-hospital mortality. The secondary outcomes were the successful liberation from V-V ECMO and the values of static lung compliance. Among the 697 registry patients, of the 582 patients who underwent chest computed tomography at V-V ECMO initiation, 394 survived and 188 died. Multivariate Cox regression showed that traction bronchiectasis and subcutaneous emphysema increased the risk of 90-day in-hospital mortality (hazard ratio [95% confidence interval] 1.77 [1.19-2.63], p = 0.005 and 1.97 [1.02-3.79], p = 0.044, respectively). The presence of traction bronchiectasis was also associated with decreased successful liberation from V-V ECMO (odds ratio: 0.27 [0.14-0.52], p < 0.001). Lower static lung compliance was associated with some chest computed tomography findings related to changes outside of pulmonary opacity, but not with the findings related to pulmonary opacity.

CONCLUSIONS

Traction bronchiectasis and subcutaneous emphysema increased the risk of 90-day in-hospital mortality in patients with severe ARDS who required V-V ECMO.

Development and validation of a rabbit model of Pseudomonas aeruginosa non-ventilated pneumonia for preclinical drug development

Background

New drugs targeting antimicrobial resistant pathogens, including Pseudomonas aeruginosa, have been challenging to evaluate in clinical trials, particularly for the non-ventilated hospital-acquired pneumonia and ventilator-associated pneumonia indications. Development of new antibacterial drugs is facilitated by preclinical animal models that could predict clinical efficacy in patients with these infections.

Methods

We report here an FDA-funded study to develop a rabbit model of non-ventilated pneumonia with Pseudomonas aeruginosa by determining the extent to which the natural history of animal disease reproduced human pathophysiology and conducting validation studies to evaluate whether humanized dosing regimens of two antibiotics, meropenem and tobramycin, can halt or reverse disease progression.

Results

In a rabbit model of non-ventilated pneumonia, endobronchial challenge with live P. aeruginosa strain 6206, but not with UV-killed Pa6206, caused acute respiratory distress syndrome, as evidenced by acute lung inflammation, pulmonary edema, hemorrhage, severe hypoxemia, hyperlactatemia, neutropenia, thrombocytopenia, and hypoglycemia, which preceded respiratory failure and death. Pa6206 increased >100-fold in the lungs and then disseminated from there to infect distal organs, including spleen and kidneys. At 5 h post-infection, 67% of Pa6206-challenged rabbits had PaO2 <60 mmHg, corresponding to a clinical cut-off when oxygen therapy would be required. When administered at 5 h post-infection, humanized dosing regimens of tobramycin and meropenem reduced mortality to 17-33%, compared to 100% for saline-treated rabbits (P<0.001 by log-rank tests). For meropenem which exhibits time-dependent bactericidal activity, rabbits treated with a humanized meropenem dosing regimen of 80 mg/kg q2h for 24 h achieved 100% T>MIC, resulting in 75% microbiological clearance rate of Pa6206 from the lungs. For tobramycin which exhibits concentration-dependent killing, rabbits treated with a humanized tobramycin dosing regimen of 8 mg/kg q8h for 24 h achieved Cmax/MIC of 9.8 ± 1.4 at 60 min post-dose, resulting in 50% lung microbiological clearance rate. In contrast, rabbits treated with a single tobramycin dose of 2.5 mg/kg had Cmax/MIC of 7.8 ± 0.8 and 8% (1/12) microbiological clearance rate, indicating that this rabbit model can detect dose-response effects.

Conclusion

The rabbit model may be used to help predict clinical efficacy of new antibacterial drugs for the treatment of non-ventilated P. aeruginosa pneumonia.

Role of virtual reality distraction technique to improve chest burns with acute respiratory distress syndrome (ARDS) following smoke inhalation in middle-aged adults - A randomized controlled study

BACKGROUND

Burns of the chest region constitute a common burn and develops skin contractures around the thorax region. Inhalation of toxic gases and chemical irritants during the fire leads to Acute Respiratory Distress Syndrome (ARDS). Breathing exercises are painful but are needed to help counteract contractures and increase lung capacity. These patients are usually in pain and extremely anxious about chest physiotherapy. Virtual reality distraction is one such technique that is gaining immense popularity when compared to other pain distraction techniques. However, studies examining the efficacy of the virtual reality distraction technique in this population are lacking.

OBJECTIVES

To find and compare the effects of the virtual reality distraction technique as a pain alleviation tool for reducing pain during chest physiotherapy in chest burns patients with ARDS in middle-aged adults.

METHODS

A randomized controlled study was conducted at the physiotherapy department between 1st Sep 2020 and 30th Dec 2022. The eligible sixty subjects were randomized into two groups: The virtual reality distraction group (n = 30) received virtual reality distraction technique and the control group (n = 30) received progressive relaxation technique before chest physiotherapy as a pain distraction technique. All the participants received chest physiotherapy as a common treatment (treatment as usual). Primary (Visual Analogue Scale - VAS) and secondary (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, peak expiratory flow (PEF), residual volume (RV), functional residual capacity (FRC), total lung capacity (TLC), RV/TLC, and diffusing capacity for carbon monoxide of the lungs (DLCO) outcome measures were measured at baseline, after four weeks, eight weeks and at six months follow up. The effects between the two groups were analyzed using the independent t-test and chi-square test. The intra-group effect was analyzed with a repeated measure ANOVA test.

RESULTS

Baseline demographic characters and study variables show homogenous distribution between the groups (p > 0.05). Four weeks following two different training protocols virtual reality distraction group shows more significant changes in pain intensity, FVC, FEV1, FEV1/FVC, PEF, RV, FRC, TLC, RV/TLC, and DLCO (p = 0.001) but not in RV (p = 0.541). The similar improvements were noted in the 8 weeks and 6 months follow up.

CONCLUSION

The reports of the study concluded that virtual reality distraction is an effective and useful technique in reducing pain and increasing lung capacity in chest burn patient with ARDS following smoke inhalation in community-dwelling middle-aged adults. In the virtual reality distraction group, the patients reported significantly less pain and clinically meaningful changes in pulmonary functions as compared to the control group (physiotherapy + relaxation).

Early transthoracic echocardiography and long-term mortality in moderate- to-severe acute respiratory distress syndrome: An analysis of the Medical Information Mart for Intensive Care database

BACKGROUND

The clinical use of transthoracic echocardiography (TTE) in patients with acute respiratory distress syndrome (ARDS) in the intensive care unit (ICU) has dramatically increased, its impact on long-term prognosis in these patients has not been studied. This study aimed to explore the effect of early-TTE on long-term mortality in patients with moderate-to-severe ARDS in ICU.

METHODS

A total of 2833 patients with moderate-to-severe ARDS who had or had not received early-TTE were obtained from the Medical Information Mart for Intensive Care (MIMIC-III) database after imputing missing values by a random forest model, patients were divided into early-TTE group and non-early-TTE group according to whether they received TTE examination in ICU. A variety of statistical methods were used to balance 41 covariates and increase the reliability of this study, including propensity score matching, inverse probability of treatment weight, covariate balancing propensity score, multivariable regression, and doubly robust estimation. Chi-Square test and t-tests were used to examine the differences between groups for categorical and continuous data, respectively.

RESULTS

There was a significant improvement in 90-day mortality in the early-TTE group compared to non-early-TTE group (odds ratio  =  0.79, 95% CI: 0.64-0.98, p-value  =  0.036), revealing a beneficial effect of early-TTE. Net-input was significantly decreased in the early-TTE group on the third day of ICU admission and throughout the ICU stay, compared with non-early-TTE group (838.57 vs. 1181.89 mL, p-value  =  0.014; 4542.54 vs. 8025.25 mL, p-value  =  0.05). There was a significant difference in the reduction of serum lactate between the two groups, revealing the beneficial effect of early-TTE (0.59 vs. 0.83, p-value  =  0.009). Furthermore, the reduction in the proportion of acute kidney injury demonstrated a correlation between early-TTE and kidney protection (33% vs. 40%, p-value < 0.001).

CONCLUSIONS

Early application of TTE is beneficial to improve the long-term mortality of patients with moderate-to-severe ARDS.

Stability and structure-activity relationship of the SPA4 peptide under ambient and stressed conditions of lung injury

Lung inflammation and injuries are major health problems. The SPA4 peptide (amino acid sequence GDFRYSDGTPVNYTNWYRGE) binds to Toll-like receptor-4 and exerts anti-inflammatory activity. In this study, we have determined the stability of the structure and structure-activity relationship of the SPA4 peptide under ambient and stressed conditions of lung injury. The SPA4 peptide was maintained at different pH and temperatures, in solutions of different ionic strengths, and simulated lung fluids. The primary and secondary structure of the SPA4 peptide was determined by ultraviolet-visible (UV-VIS) and circular dichroism (CD) spectroscopy. The activity of the SPA4 peptide was determined by measurement of secreted levels of chemokine C-X-C motif ligand 1/keratinocyte-derived chemokine (CXCL1/KC) and lactate by primary mouse lung epithelial cells against lipopolysaccharide (LPS) stimuli. Our results demonstrate the stability of the structure of the SPA4 peptide at room temperature and 4 °C over 10 days. The original UV-VIS spectra of the SPA4 peptide followed a typical pattern when incubated in solutions of pH 5.7, 7.0, and 8.0 at different temperatures, simulated lung fluids, and most of the chemical components. Slight shifts in the absorbance peaks, derivative values, and vibrational fine structures were noted in the fourth-derivative spectra of the SPA4 peptide under some conditions. An increased level of lactate is the hallmark of lung injury. The SPA4 peptide on its own and in the presence of lactate exerts anti-inflammatory activity. The primary and secondary structure and the activity of the SPA4 peptide remain intact when pre-incubated in 2 mM sodium lactate solution. The results provide important insights about the stability and structure-activity relationship of the SPA4 peptide.

Collaborative strategies for deploying artificial intelligence to complement physician diagnoses of acute respiratory distress syndrome

There is a growing gap between studies describing the capabilities of artificial intelligence (AI) diagnostic systems using deep learning versus efforts to investigate how or when to integrate AI systems into a real-world clinical practice to support physicians and improve diagnosis. To address this gap, we investigate four potential strategies for AI model deployment and physician collaboration to determine their potential impact on diagnostic accuracy. As a case study, we examine an AI model trained to identify findings of the acute respiratory distress syndrome (ARDS) on chest X-ray images. While this model outperforms physicians at identifying findings of ARDS, there are several reasons why fully automated ARDS detection may not be optimal nor feasible in practice. Among several collaboration strategies tested, we find that if the AI model first reviews the chest X-ray and defers to a physician if it is uncertain, this strategy achieves a higher diagnostic accuracy (0.869, 95% CI 0.835-0.903) compared to a strategy where a physician reviews a chest X-ray first and defers to an AI model if uncertain (0.824, 95% CI 0.781-0.862), or strategies where the physician reviews the chest X-ray alone (0.808, 95% CI 0.767-0.85) or the AI model reviews the chest X-ray alone (0.847, 95% CI 0.806-0.887). If the AI model reviews a chest X-ray first, this allows the AI system to make decisions for up to 79% of cases, letting physicians focus on the most challenging subsets of chest X-rays.

Respiratory Subsets in Patients with Moderate to Severe Acute Respiratory Distress Syndrome for Early Prediction of Death

Introduction: In patients with acute respiratory distress syndrome (ARDS), the PaO2/FiO2 ratio at the time of ARDS diagnosis is weakly associated with mortality. We hypothesized that setting a PaO2/FiO2 threshold in 150 mm Hg at 24 h from moderate/severe ARDS diagnosis would improve predictions of death in the intensive care unit (ICU). Methods: We conducted an ancillary study in 1303 patients with moderate to severe ARDS managed with lung-protective ventilation enrolled consecutively in four prospective multicenter cohorts in a network of ICUs. The first three cohorts were pooled (n = 1000) as a testing cohort; the fourth cohort (n = 303) served as a confirmatory cohort. Based on the thresholds for PaO2/FiO2 (150 mm Hg) and positive end-expiratory pressure (PEEP) (10 cm H2O), the patients were classified into four possible subsets at baseline and at 24 h using a standardized PEEP-FiO2 approach: (I) PaO2/FiO2 ≥ 150 at PEEP < 10, (II) PaO2/FiO2 ≥ 150 at PEEP ≥ 10, (III) PaO2/FiO2 < 150 at PEEP < 10, and (IV) PaO2/FiO2 < 150 at PEEP ≥ 10. Primary outcome was death in the ICU. Results: ICU mortalities were similar in the testing and confirmatory cohorts (375/1000, 37.5% vs. 112/303, 37.0%, respectively). At baseline, most patients from the testing cohort (n = 792/1000, 79.2%) had a PaO2/FiO2 < 150, with similar mortality among the four subsets (p = 0.23). When assessed at 24 h, ICU mortality increased with an advance in the subset: 17.9%, 22.8%, 40.0%, and 49.3% (p < 0.0001). The findings were replicated in the confirmatory cohort (p < 0.0001). However, independent of the PEEP levels, patients with PaO2/FiO2 < 150 at 24 h followed a distinct 30-day ICU survival compared with patients with PaO2/FiO2 ≥ 150 (hazard ratio 2.8, 95% CI 2.2−3.5, p < 0.0001). Conclusions: Subsets based on PaO2/FiO2 thresholds of 150 mm Hg assessed after 24 h of moderate/severe ARDS diagnosis are clinically relevant for establishing prognosis, and are helpful for selecting adjunctive therapies for hypoxemia and for enrolling patients into therapeutic trials.

ARDS Clinical Practice Guideline 2021

BACKGROUND

The joint committee of the Japanese Society of Intensive Care Medicine/Japanese Respiratory Society/Japanese Society of Respiratory Care Medicine on ARDS Clinical Practice Guideline has created and released the ARDS Clinical Practice Guideline 2021.

METHODS

The 2016 edition of the Clinical Practice Guideline covered clinical questions (CQs) that targeted only adults, but the present guideline includes 15 CQs for children in addition to 46 CQs for adults. As with the previous edition, we used a systematic review method with the Grading of Recommendations Assessment Development and Evaluation (GRADE) system as well as a degree of recommendation determination method. We also conducted systematic reviews that used meta-analyses of diagnostic accuracy and network meta-analyses as a new method.

RESULTS

Recommendations for adult patients with ARDS are described: we suggest against using serum C-reactive protein and procalcitonin levels to identify bacterial pneumonia as the underlying disease (GRADE 2D); we recommend limiting tidal volume to 4-8 mL/kg for mechanical ventilation (GRADE 1D); we recommend against managements targeting an excessively low SpO2 (PaO2) (GRADE 2D); we suggest against using transpulmonary pressure as a routine basis in positive end-expiratory pressure settings (GRADE 2B); we suggest implementing extracorporeal membrane oxygenation for those with severe ARDS (GRADE 2B); we suggest against using high-dose steroids (GRADE 2C); and we recommend using low-dose steroids (GRADE 1B). The recommendations for pediatric patients with ARDS are as follows: we suggest against using non-invasive respiratory support (non-invasive positive pressure ventilation/high-flow nasal cannula oxygen therapy) (GRADE 2D), we suggest placing pediatric patients with moderate ARDS in the prone position (GRADE 2D), we suggest against routinely implementing NO inhalation therapy (GRADE 2C), and we suggest against implementing daily sedation interruption for pediatric patients with respiratory failure (GRADE 2D).

CONCLUSIONS

This article is a translated summary of the full version of the ARDS Clinical Practice Guideline 2021 published in Japanese (URL: https://www.jsicm.org/publication/guideline.html ). The original text, which was written for Japanese healthcare professionals, may include different perspectives from healthcare professionals of other countries.

ARDS clinical practice guideline 2021

BACKGROUND

The joint committee of the Japanese Society of Intensive Care Medicine/Japanese Respiratory Society/Japanese Society of Respiratory Care Medicine on ARDS Clinical Practice Guideline has created and released the ARDS Clinical Practice Guideline 2021.

METHODS

The 2016 edition of the Clinical Practice Guideline covered clinical questions (CQs) that targeted only adults, but the present guideline includes 15 CQs for children in addition to 46 CQs for adults. As with the previous edition, we used a systematic review method with the Grading of Recommendations Assessment Development and Evaluation (GRADE) system as well as a degree of recommendation determination method. We also conducted systematic reviews that used meta-analyses of diagnostic accuracy and network meta-analyses as a new method.

RESULTS

Recommendations for adult patients with ARDS are described: we suggest against using serum C-reactive protein and procalcitonin levels to identify bacterial pneumonia as the underlying disease (GRADE 2D); we recommend limiting tidal volume to 4-8 mL/kg for mechanical ventilation (GRADE 1D); we recommend against managements targeting an excessively low SpO₂ (PaO₂) (GRADE 2D); we suggest against using transpulmonary pressure as a routine basis in positive end-expiratory pressure settings (GRADE 2B); we suggest implementing extracorporeal membrane oxygenation for those with severe ARDS (GRADE 2B); we suggest against using high-dose steroids (GRADE 2C); and we recommend using low-dose steroids (GRADE 1B). The recommendations for pediatric patients with ARDS are as follows: we suggest against using non-invasive respiratory support (non-invasive positive pressure ventilation/high-flow nasal cannula oxygen therapy) (GRADE 2D); we suggest placing pediatric patients with moderate ARDS in the prone position (GRADE 2D); we suggest against routinely implementing NO inhalation therapy (GRADE 2C); and we suggest against implementing daily sedation interruption for pediatric patients with respiratory failure (GRADE 2D).

CONCLUSIONS

This article is a translated summary of the full version of the ARDS Clinical Practice Guideline 2021 published in Japanese (URL: https://www.jrs.or.jp/publication/jrs_guidelines/). The original text, which was written for Japanese healthcare professionals, may include different perspectives from healthcare professionals of other countries.

Predictive value of computed tomography for short-term mortality in patients with acute respiratory distress syndrome: a systematic review

The best available evidence and the predictive value of computed tomography (CT) findings for prognosis in patients with acute respiratory distress syndrome (ARDS) are unknown. We systematically searched three electronic databases (MEDLINE, CENTRAL, and ClinicalTrials.gov). A total of 410 patients from six observational studies were included in this systematic review. Of these, 143 patients (34.9%) died due to ARDS in short-term. As for CT grade, the CTs used ranged from 4- to 320-row. The index test included diffuse attenuations in one study, affected lung in one study, well-aerated lung region/predicted total lung capacity in one study, CT score in one study and high-resolution CT score in two studies. Considering the CT findings, pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 62% (95% confidence interval [CI] 30–88%), 76% (95% CI 57–89%), 2.58 (95% CI 2.05–2.73), 0.50 (95% CI 0.21–0.79), and 5.16 (95% CI 2.59–3.46), respectively. This systematic review revealed that there were major differences in the definitions of CT findings, and that the integration of CT findings might not be adequate for predicting short-term mortality in ARDS. Standardisation of CT findings and accumulation of further studies by CT with unified standards are warranted.

Estimating the incidence of spontaneous breathing effort of mechanically ventilated patients using a non-linear auto regressive (NARX) model

BACKGROUND AND OBJECTIVE

Mechanical ventilation (MV) provides breathing support for acute respiratory distress syndrome (ARDS) patients in the intensive care unit, but is difficult to optimize. Too much, or too little of pressure or volume support can cause further ventilator-induced lung injury, increasing length of MV, cost and mortality. Patient-specific respiratory mechanics can help optimize MV settings. However, model-based estimation of respiratory mechanics is less accurate when patient exhibit un-modeled spontaneous breathing (SB) efforts on top of ventilator support. This study aims to estimate and quantify SB efforts by reconstructing the unaltered passive mechanics airway pressure using NARX model.

METHODS

Non-linear autoregressive (NARX) model is used to reconstruct missing airway pressure due to the presence of spontaneous breathing effort in mv patients. Then, the incidence of SB patients is estimated. The study uses a total of 10,000 breathing cycles collected from 10 ARDS patients from IIUM Hospital in Kuantan, Malaysia. In this study, there are 2 different ratios of training and validating methods. Firstly, the initial ratio used is 60:40 which indicates 600 breath cycles for training and remaining 400 breath cycles used for testing. Then, the ratio is varied using 70:30 ratio for training and testing data.

RESULTS AND DISCUSSION

The mean residual error between original airway pressure and reconstructed airway pressure is denoted as the magnitude of effort. The median and interquartile range of mean residual error for both ratio are 0.0557 [0.0230 - 0.0874] and 0.0534 [0.0219 - 0.0870] respectively for all patients. The results also show that Patient 2 has the highest percentage of SB incidence and Patient 10 with the lowest percentage of SB incidence which proved that NARX model is able to perform for both higher incidence of SB effort or when there is a lack of SB effort.

CONCLUSION

This model is able to produce the SB incidence rate based on 10% threshold. Hence, the proposed NARX model is potentially useful to estimate and identify patient-specific SB effort, which has the potential to further assist clinical decisions and optimize MV settings.

Effects of High-Resolution CT Changes on Prognosis Predictability in Acute Respiratory Distress Syndrome with Diffuse Alveolar Damage

Diffuse alveolar damage (DAD) is the pathological hallmark of acute respiratory distress syndrome (ARDS). DAD is independently correlated with higher mortality compared with the absence of DAD. Traction bronchiectasis in areas of ground-glass opacity or consolidation is associated with the late fibroproliferative or fibrotic phase of DAD. This study examined whether the 60-day mortality related to DAD could be predicted using high-resolution computed tomography (HRCT) findings and HRCT scores. A total of 34 patients with DAD who received HRCT within 7 days of ARDS diagnosis were enrolled; they were divided into a 60-day survival group and a nonsurvival group, with 17 patients in each group. Univariate and multivariate binary regression analyses and the receiver operating characteristic curve revealed that only the total percentage of the area with traction bronchiectasis or bronchiolectasis was an independent predictor of 60-day mortality (odds ratio, 1.067; 95% confidence interval (CI), 1.011–1.126) and had favorable predictive performance (area under the curve (AUC): 0.784; 95% CI, 0.621–0.946; cutoff, 21.7). Physiological variables, including age, days from ARDS to HRCT, the sequential organ failure assessment (SOFA) score, the PaO₂/fraction of inspired oxygen (FiO₂) ratio, dynamic driving pressure, and dynamic mechanical power, were not discriminative between 60-day survival and nonsurvival. In conclusion, the extent of fibroproliferation on HRCT in early ARDS, presented as the total percentage of area with bronchiectasis or bronchiolectasis, is an independent positive predictor with a favorable predictive ability for the 60-day mortality of DAD.

Relationship between Mechanical Ventilation and Histological Fibrosis in Patients with Acute Respiratory Distress Syndrome Undergoing Open Lung Biopsy

Background: Mechanical ventilation brings the risk of ventilator-induced lung injury, which can lead to pulmonary fibrosis and prolonged mechanical ventilation. Methods: A retrospective analysis of patients with acute respiratory distress syndrome (ARDS) who received open lung biopsy between March 2006 and December 2019. Results: A total of 68 ARDS patients receiving open lung biopsy with diffuse alveolar damage (DAD; the hallmark pathology of ARDS) were analyzed and stratified into non-fibrosis (n = 56) and fibrosis groups (n = 12). The duration of ventilator usage and time spent in the intensive care unit and hospital stay were all significantly higher in the fibrosis group. Hospital mortality was higher in the fibrosis than in the non-fibrosis group (67% vs. 57%, p = 0.748). A multivariable logistic regression model demonstrated that mechanical power at ARDS diagnosis and ARDS duration before biopsy were independently associated with histological fibrosis at open lung biopsy (odds ratio 1.493 (95% CI 1.014–2.200), p = 0.042; odds ratio 1.160 (95% CI 1.052–1.278), p = 0.003, respectively). Conclusions: Our findings indicate that prompt action aimed at staving off injurious mechanical stretching of lung parenchyma and subsequent progression to fibrosis may have a positive effect on clinical outcomes.

Short-term protective effect of octreotide on the lungs of rats with experimentally induced sepsis

BACKGROUND

Acute respiratory distress syndrome is a devastating complication of severe sepsis. Preclinical models suggest that direct lung injury begins with attack to the lung epithelium, but indirect lung injury results from systemic endothelial damage due to inflammatory mediators. The aim of the present study was to explore the effect of octreotide on lungs in a surgically induced sepsis model in rats.

METHODS

We used 32 male Sprague Dawley rats and divided into four groups. Group 1: Normal (non-operative and orally fed control, n=8); Group 2: Sham operated (n=8); Group 3: Cecal ligation and puncture (CLP) (untreated group, n=8); and Group 4: CLP and 100 µg/kg octreotide i.p. (n=8). For sepsis, CLP procedure was performed on 16 rats to induce a sepsis model. All groups were analyzed, their blood was taken for arterial blood gas analysis. For histological examination, lung tissues were removed and sections were prepared.

RESULTS

In histological examination, if we compare CLP + Octreotide with only CLP group in CLP + Octreotide group decreased inflammatory cell infiltration in alveolar and interstitial area as well as edema, bleeding, when CLP group was compared with octreotide group, all histopathological parameters improved significantly and the severity index decreased from 3 to 1. For arterial blood gas, when CLP and octreotide groups were compared with CLP group, it was observed that there was a significant change in favor of healing and that they almost came up to controls and sham group.

CONCLUSION

It could be hypothesized that it would be beneficial to administer octreotide for ameliorate lung injury state in sepsis patients.

Effect of Dihydropyridine Calcium Channel Blocker on Mortality of Hypertension Patients With Moderate-Severe Pulmonary Acute Respiratory Distress Syndrome: A Multicenter Retrospective Observational Cohort Study

The aim was to evaluate the effect of dihydropyridine calcium channel blocker on the prognosis for moderate-severe pulmonary acute respiratory distress syndrome in hypertension patients.

DESIGN

A retrospective, observational, multicenter cohort study.

SETTING

A total of 307 patients without propensity score matching and 186 adult inpatients with propensity score matching diagnosed with hypertension and moderate-severe pulmonary acute respiratory distress syndrome in five teaching hospitals in Jiangsu province, China, from December 2015 to December 2020 were enrolled.

PATIENTS

A total of 307 patients without propensity score matching and 186 patients with propensity score matching diagnosed with hypertension and moderate-severe pulmonary acute respiratory distress syndrome were included in the final analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic characteristics and clinical characteristics were recorded. The propensity score matching method was used to eliminate the difference between group with dihydropyridine calcium channel blocker and group without dihydropyridine calcium channel blocker. The primary outcome was in-hospital mortality. We used univariate and multivariate regression analyses for both patients with or without propensity score matching to assess the effect of these variables on mortality. In the subset of 186 patients with propensity score matching, in-hospital mortality was 53.2%. Inpatient mortality was significantly higher in patients treated with dihydropyridine calcium channel blocker than in those not treated with dihydropyridine calcium channel blocker of patients without propensity score matching (65.4% vs 40.4%; p < 0.01). Multivariate analysis for patients without propensity score matching showed that dihydropyridine calcium channel blocker (hazard ratio, 1.954; 95% CI, 1.415-2.699), lactate dehydrogenase greater than or equal to 600 U/L (hazard ratio, 3.809; 95% CI, 2.106-4.531), and lactate greater than or equal to 2 mmol/L (hazard ratio, 1.454; 95% CI, 1.041-2.029) were independently associated with in-hospital mortality. Based on univariate analysis for patients with propensity score matching, dihydropyridine calcium channel blocker (hazard ratio, 2.021; 95% CI, 1.333-3.064), lactate dehydrogenase greater than or equal to 600 U/L (hazard ratio, 4.379; 95% CI, 2.642-7.257), and lactate greater than or equal to 2 mmol/L (hazard ratio, 2.461; 95% CI, 1.534-3.951) were independently associated with in-hospital mortality. In contrast, patients not treated with dihydropyridine calcium channel blocker had a significant survival advantage over those treated with dihydropyridine calcium channel blocker in both patients without or with propensity score matching (p < 0.001; p = 0.001 by Kaplan-Meier analysis).

CONCLUSIONS

Dihydropyridine calcium channel blocker, lactate dehydrogenase greater than or equal to 600 U/L, and lactate greater than or equal to 2 mmol/L at admission were independent risk factors for patients with hypertension and moderate-severe pulmonary acute respiratory distress syndrome.

Effect of different levels of PEEP on mortality in ICU patients without acute respiratory distress syndrome: systematic review and meta-analysis with trial sequential analysis

OBJECTIVE

To determine whether higher positive end- expiratory pressure (PEEP) could provide a survival advantage for patients without acute respiratory distress syndrome (ARDS) compared with lower PEEP.

METHODS

Eligible studies were identified through searches of Embase, Cochrane Library, Web of Science, Medline, and Wanfang database from inception up to 1 June 2021. Trial sequential analysis (TSA) was used in this meta-analysis.

DATA SYNTHESIS

Twenty-seven randomized controlled trials (RCTs) were identified for further evaluation. Higher and lower PEEP arms included 1330 patients and 1650 patients, respectively. A mean level of 9.6±3.4 cmH₂O was applied in the higher PEEP groups and 1.9±2.6 cmH₂O was used in the lower PEEP groups. Higher PEEP, compared with lower PEEP, was not associated with reduction of all-cause mortality (RR 1.03; 95% CI 0.91-1.18; P =0.627), and 28-day mortality (RR 1.07 ; 95% CI 0.92-1.24; P =0.365). In terms of risk of ARDS (RR 0.43; 95% CI 0.24-0.78; P =0.005), duration of intensive care unit (MD -1.04; 95%CI-1.36 to -0.73; P < 0.00001), and oxygenation (MD 40.30; 95%CI 0.94 to 79.65; P = 0.045), higher PEEP was superior to lower PEEP. Besides, the pooled analysis showed no significant differences between groups both in the duration of mechanical ventilation (MD 0.00; 95%CI-0.13 to 0.13; P = 0.996) and hospital stay (MD -0.66; 95%CI-1.94 to 0.61; P = 0.309). More importantly, lower PEEP did not increase the risk of pneumonia, atelectasis, barotrauma, hypoxemia, or hypotension among patients compared with higher PEEP. The TSA analysis showed that the results of all-cause mortality and 28-day mortality might be false-negative results.

CONCLUSIONS

Our results suggest that a lower PEEP ventilation strategy was non-inferior to a higher PEEP ventilation strategy in ICU patients without ARDS, with no increased risk of all-cause mortality and 28-day mortality. Further high-quality RCTs should be performed to confirm these findings.

Cytokine Adsorption in Severe Acute Respiratory Failure Requiring Veno-Venous Extracorporeal Membrane Oxygenation

Veno-venous extracorporeal membrane oxygenation (V-V ECMO) is a last resort treatment option for patients with acute respiratory failure (acute respiratory distress syndrome [ARDS]). Cytokine adsorption has been incorporated in the management of some of these patients on an individual basis to control the imbalance of danger-associated molecular patterns and proinflammatory cytokines. However, little is known about the combination of V-V ECMO and cytokine adsorption as earlier reports contained mixed patient cohorts in terms of disease and mode of ECMO, veno-venous and veno-arterial. We here report single-center registry data of nine all-comers with severe ARDS treated with V-V ECMO and cytokine adsorption using the CytoSorb adsorber compared with a control group of nine propensity score matched patients undergoing V-V ECMO support without cytokine adsorption. Even though Respiratory ECMO Survival Prediction and PRedicting dEath for SEvere ARDS on V-V ECMO scores predicted a higher mortality in the cytokine adsorption group, mortality was numerically reduced in the patients undergoing V-V ECMO and cytokine removal compared with V-V ECMO alone. The need for fluid resuscitation and vasopressor support as well as lactate levels dropped significantly in the cytokine adsorption group within 72 hours, whereas vasopressor need and lactate levels did not decrease significantly in the control group. Therefore, our data suggest that cytokine adsorption might be beneficial in patients with severe ARDS requiring V-V ECMO support.

Novel criteria to classify ARDS severity using a machine learning approach

Background

Usually, arterial oxygenation in patients with the acute respiratory distress syndrome (ARDS) improves substantially by increasing the level of positive end-expiratory pressure (PEEP). Herein, we are proposing a novel variable [PaO₂/(FiO₂xPEEP) or P/FP_E] for PEEP ≥ 5 to address Berlin’s definition gap for ARDS severity by using machine learning (ML) approaches.

Methods

We examined P/FP_E values delimiting the boundaries of mild, moderate, and severe ARDS. We applied ML to predict ARDS severity after onset over time by comparing current Berlin PaO₂/FiO₂ criteria with P/FP_E under three different scenarios. We extracted clinical data from the first 3 ICU days after ARDS onset (N = 2738, 1519, and 1341 patients, respectively) from MIMIC-III database according to Berlin criteria for severity. Then, we used the multicenter database eICU (2014–2015) and extracted data from the first 3 ICU days after ARDS onset (N = 5153, 2981, and 2326 patients, respectively). Disease progression in each database was tracked along those 3 ICU days to assess ARDS severity. Three robust ML classification techniques were implemented using Python 3.7 (LightGBM, RF, and XGBoost) for predicting ARDS severity over time.

Results

P/FP_E ratio outperformed PaO₂/FiO₂ ratio in all ML models for predicting ARDS severity after onset over time (MIMIC-III: AUC 0.711–0.788 and CORR 0.376–0.566; eICU: AUC 0.734–0.873 and CORR 0.511–0.745).

Conclusions

The novel P/FP_E ratio to assess ARDS severity after onset over time is markedly better than current PaO₂/FiO₂ criteria. The use of P/FP_E could help to manage ARDS patients with a more precise therapeutic regimen for each ARDS category of severity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03566-w.

A Simple-to-Use Web-Based Calculator for Survival Prediction in Acute Respiratory Distress Syndrome

Background: The aim of this study was to construct and validate a simple-to-use model to predict the survival of patients with acute respiratory distress syndrome.

Methods: A total of 197 patients with acute respiratory distress syndrome were selected from the Dryad Digital Repository. All eligible individuals were randomly stratified into the training set (n=133) and the validation set (n=64) as 2: 1 ratio. LASSO regression analysis was used to select the optimal predictors, and receiver operating characteristic and calibration curves were used to evaluate accuracy and discrimination of the model. Clinical usefulness of the model was also assessed using decision curve analysis and Kaplan-Meier analysis.

Results: Age, albumin, platelet count, PaO₂/FiO₂, lactate dehydrogenase, high-resolution computed tomography score, and etiology were identified as independent prognostic factors based on LASSO regression analysis; these factors were integrated for the construction of the nomogram. Results of calibration plots, decision curve analysis, and receiver operating characteristic analysis showed that this model has good predictive ability of patient survival in acute respiratory distress syndrome. Moreover, a significant difference in the 28-day survival was shown between the patients stratified into different risk groups (P < 0.001). For convenient application, we also established a web-based calculator (https://huangl.shinyapps.io/ARDSprognosis/).

Conclusions: We satisfactorily constructed a simple-to-use model based on seven relevant factors to predict survival and prognosis of patients with acute respiratory distress syndrome. This model can aid personalized treatment and clinical decision-making.

Utility of SpO2/FiO2 ratio for acute hypoxemic respiratory failure with bilateral opacities in the ICU

Acute hypoxemic respiratory failure (AHRF) with bilateral opacities causes fatalities in the intensive care unit (ICU). It is often difficult to identify the causes of AHRF at the time of admission. The SpO2 to FiO2 (S/F) ratio has been recently used as a non-invasive and alternative marker of the PaO2/FiO2 (P/F) ratio in acute respiratory failure. This retrospective cohort study was conducted from October 2010 to March 2019 at the Showa University Hospital, Tokyo, Japan. We enrolled 94 AHRF patients who had bilateral opacities and received mechanical ventilation in ICU to investigate their prognostic markers including S/F ratio. Significant differences were observed for APACHE II, S/F ratio, PaO2/FiO2 (P/F) ratio, and ventilator-free-days at day 28 for ICU mortality, and for age, S/F ratio, P/F ratio, duration of mechanical ventilation, and ventilator-free days at day 28 for hospital mortality. Multivariate logistic regression analysis showed that the S/F ratio was significantly and independently associated with the risk of death during in ICU (p = 0.003) and hospitalization (p = 0.002). The area under the receiver operating characteristic curves (AUC) based on the S/F ratio were significantly greater than those based on simplified acute physiology score (SAPS) II and sequential organ failure assessment (SOFA) for ICU mortality (0.785 in S/F ratio vs. 0.575 in SAPS II, p = 0.012; 0.785 in S/F ratio vs 0.594 in SOFA, p = 0.021) and for hospital mortality (0.701 in S/F ratio vs. 0.502 in SAPS II, p = 0.012; 0.701 in S/F ratio vs. 0.503 in SOFA, p = 0.005). In the subanalysis for bacterial pneumonia and interstitial lung disease groups, the AUC based on the S/F ratio was the greatest among all prognostic markers, including APACHE II, SAPS II, and SOFA. The S/F ratio may be a useful and noninvasive predictive prognostic marker for acute hypoxemic respiratory failure with bilateral opacities in the ICU.

Early cardiac injury in acute respiratory distress syndrome: comparison of two experimental models

Acute respiratory distress syndrome (ARDS) is characterized by diffuse lung damage, inflammation, oedema formation, and surfactant dysfunction leading to hypoxemia. Severe ARDS can accelerate the injury of other organs, worsening the patient´s status. There is an evidence that the lung tissue injury affects the right heart function causing cor pulmonale. However, heart tissue changes associated with ARDS are still poorly known. Therefore, this study evaluated oxidative and inflammatory modifications of the heart tissue in two experimental models of ARDS induced in New Zealand rabbits by intratracheal instillation of neonatal meconium (100 mg/kg) or by repetitive lung lavages with saline (30 ml/kg). Since induction of the respiratory insufficiency, all animals were oxygen-ventilated for next 5 h. Total and differential counts of leukocytes were measured in the arterial blood, markers of myocardial injury [(troponin, creatine kinase - myocardial band (CK-MB), lactate dehydrogenase (LD)] in the plasma, and markers of inflammation [tumour necrosis factor (TNF)alpha, interleukin (IL)-6], cardiovascular risk [galectin-3 (Gal-3)], oxidative changes [thiobarbituric acid reactive substances (TBARS), 3-nitrotyrosine (3NT)], and vascular damage [receptor for advanced glycation end products (RAGE)] in the heart tissue. Apoptosis of heart cells was investigated immunohistochemically. In both ARDS models, counts of total leukocytes and neutrophils in the blood, markers of myocardial injury, inflammation, oxidative and vascular damage in the plasma and heart tissue, and heart cell apoptosis increased compared to controls. This study indicates that changes associated with ARDS may contribute to early heart damage what can potentially deteriorate the cardiac function and contribute to its failure.

Single cell RNA sequencing identifies an early monocyte gene signature in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) results from overwhelming pulmonary inflammation. Prior bulk RNA sequencing provided limited insights into ARDS pathogenesis. We used single cell RNA sequencing to probe ARDS at a higher resolution. PBMCs of patients with pneumonia and sepsis with early ARDS were compared with those of sepsis patients who did not develop ARDS. Monocyte clusters from ARDS patients revealed multiple distinguishing characteristics in comparison with monocytes from patients without ARDS, including downregulation of SOCS3 expression, accompanied by a proinflammatory signature with upregulation of multiple type I IFN-induced genes, especially in CD16+ cells. To generate an ARDS risk score, we identified upregulation of 29 genes in the monocytes of these patients, and 17 showed a similar profile in cells of patients in independent cohorts. Monocytes had increased expression of RAB11A, known to inhibit neutrophil efferocytosis; ATP2B1, a calcium pump that exports Ca2+ implicated in endothelial barrier disruption; and SPARC, associated with processing of procollagen to collagen. These data show that monocytes of ARDS patients upregulate expression of genes not just restricted to those associated with inflammation. Together, our findings identify molecules that are likely involved in ARDS pathogenesis that may inform biomarker and therapeutic development.

Prediction of outcome in patients with ARDS: A prospective cohort study comparing ARDS-definitions and other ARDS-associated parameters, ratios and scores at intubation and over time

Background

Early recognition of high-risk-patients with acute respiratory distress syndrome (ARDS) might improve their outcome by less protracted allocation to intensified therapy including extracorporeal membrane oxygenation (ECMO). Among numerous predictors and classifications, the American European Consensus Conferenece (AECC)- and Berlin-definitions as well as the oxygenation index (OI) and the Murray-/Lung Injury Score are the most common. Most studies compared the prediction of mortality by these parameters on the day of intubation and/or diagnosis of ARDS. However, only few studies investigated prediction over time, in particular for more than three days.

Objective

Therefore, our study aimed at characterization of the best predictor and the best day(s) to predict 28-days-mortality within four days after intubation of patients with ARDS.

Methods

In 100 consecutive patients with ARDS severity according to OI (mean airway pressure*F_iO₂/p_aO₂), modified Murray-score without radiological points (Murray_mod), AECC- and Berlin-definition, were daily documented for four days after intubation. In the subgroup of 49 patients with transpulmonary thermodilution (TPTD) monitoring (PiCCO), extravascular lung water index (EVLWI) was measured daily.

Primary endpoint

Prediction of 28-days-mortality (Area under the receiver-operating-characteristic curve (ROC-AUC)); IBM SPSS 26.

Results

In the totality of patients the best prediction of 28-days-mortality was found on day-1 and day-2 (mean ROC-AUCs for all predictors/scores: 0.632 and 0.620). OI was the best predictor among the ARDS-scores (AUC=0.689 on day-1; 4-day-mean AUC = 0.625). AECC and Murray_mod had 4-day-means AUCs below 0.6. Among the 49 patients with TPTD, EVLWI (4-day-mean AUC=0.696) and OI (4-day-mean AUC=0.695) were the best predictors. AUCs were 0.789 for OI on day-1, and 0.786 for EVLWI on day-2. In binary regression analysis of patients with TPTD, EVLWI (B=-0.105; Wald=7.294; p=0.007) and OI (B=0.124; Wald=7.435; p=0.006) were independently associated with 28-days-mortality. Combining of EVLWI and OI provided ROC-AUCs of 0.801 (day-1) and 0.824 (day-2). Among the totality of patients, the use of TPTD-monitoring „per se“ and a lower SOFA-score were independently associated with a lower 28-days-mortality.

Conclusions

Prognosis of ARDS-patients can be estblished within two days after intubation. The best predictors were EVLWI and OI and their combination. TPTD-monitoring „per se“ was independently associated with reduced mortality.

The effect of blood lactate and NT-proBNP predict the survival in patients with invasive mechanical ventilation

Background

Respiratory failure is one of the most common critical diseases. It has already been reported that invasive mechanical ventilation (IMV) should be used to treat respiratory failure. The present study aims to evaluate the prognostic value of blood lactate and NT-proBNP in patients with IMV.

Methods

We retrospectively included 353 patients who were hospitalized in the emergency department of Shanghai Sixth People’s Hospital from 2016 to 2019. All patients had IMV. R&D Human Premixed Multi-Analyte Kit detected the expression of various inflammatory factors in serum. Receiver operating characteristic (ROC) curve analysis, survival analysis, and multivariate cox proportional hazards analysis were implemented as statistical analysis methods.

Results

The mean duration of hospitalization was 25.5±20.6 days. Twenty-four men and 41 women died. Compared with the survivors, the nonsurvivors were older, had different types of diagnosis, longer ventilation time, and shorter survival time (P<0.05). Also, the expression levels of PCT, NT-proBNP, lactate in 12 h and lactate in 24 h in the nonsurvivors were significantly higher than those in the survivor group (P<0.05). There was a significant correlation between these parameters and ventilation times (P<0.001). The results showed that age, NT-proBNP, and lactate were independent predictors of survival rate. ROC analysis showed that the cut-off values of age, NT-proBNP and lactate were 61.5 years, 230.5 pg/mL and 3.7 mmol/L, respectively. Patients aged ≥61.5 years or NT-proBNP ≥230.5 pg/mL or lactate ≥3.7 mmol/L had a worse prognosis. Therefore, patients with three parameters higher than cut-off value had the lowest survival rate, while patients with three parameters lower than cut-off value had the best survival rate.

Conclusions

Blood lactate and NT-proBNP may be used as biomarkers to predict the prognosis of patients undergoing IMV.