Factors associated with mortality in acute respiratory failure patients without acute respiratory distress syndrome.

Background: Excess tidal volume and driving pressure were associated with increased mortality in patients with acute respiratory distress syndrome (ARDS). Still, the appropriate mechanical ventilation strategy for patients who do not have ARDS needs to be understood. This study aimed to identify risk factors for mortality in acute respiratory failure patients without ARDS. Methods: We included all mechanically ventilated patients who did not meet the criteria for ARDS and were admitted to the medical intensive care unit (ICU) from October 2017 to September 2018. Patients who had tracheostomy before admission, were intubated for more than 24 hours before transfer to ICU, or underwent extracorporeal membrane oxygenation within 24 hours of ICU admission were excluded. Clinical and physiologic data were recorded and compared between survived and non-survived patients. Results: Of 289 patients with acute respiratory failure, 134 patients without ARDS were included; 69 (51%) died within 28 days. Demographics, principal diagnosis, and lung injury score on the first day of admission were not significantly different between survived and non-survived patients. In multivariate analysis, higher peak inspiratory pressure (PIP) during the first 3 days of admission [odds ratio (OR) 1.11, 95% confidence interval (CI): 1.01-1.22, P=0.04], higher sequential organ failure assessment score (OR 1.15, 95% CI: 1.04-1.28, P=0.008) and underlying cerebrovascular diseases (OR 7.09, 95% CI: 1.78-28.28, P=0.006) were independently associated with mortality in these patients, whereas dynamic lung compliance (Cdyn) and respiratory rate were not associated with mortality in the multivariate model. Conclusions: Mortality was high in mechanically ventilated patients without ARDS. Higher PIP is a potentially modifiable risk factor for mortality in these patients, independent of the baseline Cdyn. Underlying cerebrovascular diseases and increased disease severity are also independent factors associated with 28-day mortality.

Assessment of phosphatemia at admission to the intensive care unit to predict mechanical ventilation among patients with acute exacerbation of chronic obstructive pulmonary disease: a retrospective cohort study.

Background: Hypophosphatemia has been reported to impair diaphragmatic function in patients with chronic obstructive pulmonary disease (COPD). However, little is known about the role of dysphosphatemia at admission [plasmatic phosphate concentration at intensive care unit (ICU) admission (T0-Ph)] to the ICU and respiratory outcomes among patients with severe acute COPD exacerbation. We aimed to assess the value of T0-Ph as a predictive factor of invasive mechanical ventilation (MV) during ICU stay. Methods: We retrospectively included consecutive patients admitted to the ICU for a severe acute exacerbation of COPD between May 2015 and December 2018. Logistic multivariate regression analysis was performed to identify association between T0-Ph and the need for invasive MV during the ICU stay. Results: We included 198 patients of whom 132 (67%) were male. The median age was 70 [interquartile range (IQR), 61-77] years. Nine (4.5%) patients died in the ICU. Median T0-Ph was significantly higher among patients requiring invasive MV as compared to non-intubated patients [1.23 (IQR, 1.07-1.41) and 1.09 (IQR, 0.91-1.27) mmol/L; P=0.005]. By multivariate analysis, pneumonia [odds ratio (OR) =6.42; 95% confidence interval (CI): 2.78-15.96; P<0.0001) and a history of intubation (OR =3.33; 95% CI: 0.97-11.19; P=0.05) were independently associated with the need for invasive MV, whereas T0-Ph was not (OR =1.75; 95% CI: 0.72-4.44; P=0.22). Conclusions: T0-Ph was significantly higher in patients requiring invasive MV. However, T0-Ph was not associated with the need for invasive MV in multivariate analysis.

Identification of key genes affecting ventilator-induced diaphragmatic dysfunction in diabetic mice.

Background: Mechanical ventilation (MV) is often required in critically ill patients. However, prolonged mechanical ventilation can lead to Ventilator-induced diaphragmatic dysfunction (VIDD), resulting in difficulty in extubation after tracheal intubation, prolonged ICU stay, and increased mortality. At present, the incidence of diabetes is high in the world, and the prognosis of diabetic patients with mechanical ventilation is generally poor. Therefore, the role of diabetes in the development of VIDD needs to be discovered. Methods: MV modeling was performed on C57 mice and DB mice, and the control group was set up in each group. After 12 h of mechanical ventilation, the muscle strength of the diaphragm was measured, and the muscle fiber immunofluorescence staining was used to verify the successful establishment of the MV model. RNA sequencing (RNA-seq) method was used to detect mRNA expression levels of the diaphragms of each group, and then differential expressed gene analysis, Heatmap analysis, WGCNA analysis, Venn analysis, GO and KEGG enrichment analysis were performed. qRT-PCR was used to verify the expression of the selected mRNAs. Results: Our results showed that, compared with C57 control mice, the muscle strength and muscle fiber cross-sectional area of mice after mechanical ventilation decreased, and DB mice showed more obvious in this respect. RNA-seq showed that these differential expressed (DE) mRNAs were mainly related to genes such as extracellular matrix, collagen, elastic fiber and Fbxo32. GO and KEGG enrichment analysis showed that the signaling pathways associated with diabetes were mainly as follows: extracellular matrix (ECM), protein digestion and absorption, PI3K-Akt signaling pathway, calcium signaling pathway, MAPK signaling pathway and AGE-RAGE signaling pathway in diabetic complications, etc. ECM has the closest relationship with VIDD in diabetic mice. The key genes determined by WGCNA and Venn analysis were validated by quantitative real-time polymerase chain reaction (qRT-PCR), which exhibited trends similar to those observed by RNA-seq. Conclusion: VIDD can be aggravated in diabetic environment. This study provides new evidence for mRNA changes after mechanical ventilation in diabetic mice, suggesting that ECM and collagen may play an important role in the pathophysiological mechanism and progression of VIDD in diabetic mice, and provides some clues for the research, diagnosis, and treatment of VIDD in diabetic context.

Unifying Endotracheal Intracuff-Pressure Monitoring in the Intensive Care Unit: Bridging the Gap Between Standardization and Neglect.

Endotracheal cuff-pressure monitoring is a critical component of patient care in the intensive care unit, ensuring the safety and efficacy of mechanical ventilation. Despite its importance, there remains a lack of standardized protocols regarding optimal pressure targets and documentation practices. This editorial examines the significance of endotracheal intracuff-pressure monitoring in enhancing patient outcomes, highlighting the challenges and potential solutions in clinical practice.

Prognostic value of initial routine laboratory blood tests in patients with aneurysmal subarachnoid hemorrhage requiring mechanical ventilation: a retrospective cohort study.

Background: Aneurysmal subarachnoid hemorrhage (aSAH) necessitating mechanical ventilation (MV) presents a serious challenge for intensivists. Laboratory blood tests reflect individual physiological and biochemical states, and provide a useful tool for identifying patients with critical condition and stratifying risk levels of death. This study aimed to determine the prognostic role of initial routine laboratory blood tests in these patients. Methods: This retrospective cohort study included 190 aSAH patients requiring MV in the neurosurgical intensive care unit from December 2019 to March 2022. Follow-up evaluation was performed in May 2022 via routine outpatient appointment or telephone interview. The primary outcomes were death occurring within 7 days after discharge (short-term mortality) or reported at time of follow-up (long-term mortality). Clinico-demographic and radiological characteristics, initial routine laboratory blood tests (e.g., metabolic panels and arterial blood gas analysis), and treatment were analyzed and compared in relation to mortality. Multivariable logistic and Cox regression analyses, with adjustment of other clinical predictors, were performed to determine independent laboratory test predictors for short- and long-term mortality, respectively. Results: The patients had a median age of 62 years, with a median World Federation of Neurosurgical Societies grade (WFNS) score of 5 and a median modified Fisher grade (mFisher) score of 4. The short- and long-term mortality of this cohort were 60.5% and 65.3%, respectively. Compared with survivors, non-survivors had more severe disease upon admission based on neurological status and imaging features and a shorter disease course, and were more likely to receive conservative treatment. Initial ionized calcium was found to be independently associate with both short-term [adjusted odds ratio (OR): 0.92; 95% confidence interval (CI): 0.86 to 0.99; P=0.020] and long-term mortality [adjusted hazard ratio (HR): 0.95; 95% CI: 0.92 to 0.99; P=0.010], after adjusting for potential confounders. Moreover, the admission glucose level was found to be associated only with short-term mortality (adjusted OR: 1.19; 95% CI: 1.06 to 1.34; P=0.004). Conclusions: Laboratory screening may provide a useful tool for the management of aSAH patients requiring MV in stratifying risk levels for mortality and for better clinical decision-making. Further study is needed to validate the effects of calcium supplementation and glucose-lowering therapy on the outcomes in this disease.

The accuracy of simplified calculation of mechanical power: a simulation study.

Background: Mechanical ventilation (MV) is an important life-saving method in the intensive care unit (ICU). A lower mechanical power (MP) is associated with a better MV strategy. However, traditional MP calculating methods are complicated, and algebraic formulas seem to be rather practical. The aim of the present study was to compare the accuracy and application of different algebraic formulas calculating MP. Methods: A lung simulator, TestChest, was used to simulate pulmonary compliance variations. Using the TestChest system software, the parameters, including compliance and airway resistance, were set to simulate various acute respiratory distress syndrome (ARDS) lungs. Ventilator was also set to volume- and pressure-controlled modes with various parameter values (respiratory rate, RR, time of inspiration, Tinsp, positive end-expiratory pressure, PEEP) to ventilate the simulated lung of ARDS (with various respiratory system compliance, Crs). For the lung simulator, resistance of airway (Raw) was fixed to 5 cmH2O/L/s. Crs below lower inflation point (LIP) or above upper inflation point (UIP) was set to 10 mL/cmH2O. The reference standard geometric method was calculated offline with a customized software. Three algebraic formulas for volume-controlled and three for pressure-controlled were used to calculate MP. Results: The performances of the formulas were different, although the derived MP were significantly correlated with that derived from the reference method (R2>0.80, P<0.001). Under volume-controlled ventilation, medians of MP calculated with one equation was significantly lower than that with the reference method (P<0.001). Under pressure-controlled ventilation, median of MP calculated with two equations were significantly higher (P<0.001). The maximum difference was over 70% of the MP value calculated with the reference method. Conclusions: The algebraic formulas may introduce considerably large bias under the presented lung conditions, especially in moderate to severe ARDS. Cautious is required when selecting adequate algebraic formulas to calculate MP based on the formula's premises, ventilation mode, and patients' status. In clinical practice, the trend rather than the value of MP calculated by formulas should require more attention.

A Comparative Study on Predication of Appropriate Mechanical Ventilation Mode through Machine Learning Approach.

Ventilation mode is one of the most crucial ventilator settings, selected and set by knowledgeable critical care therapists in a critical care unit. The application of a particular ventilation mode must be patient-specific and patient-interactive. The main aim of this study is to provide a detailed outline regarding ventilation mode settings and determine the best machine learning method to create a deployable model for the appropriate selection of ventilation mode on a per breath basis. Per-breath patient data is utilized, preprocessed and finally a data frame is created consisting of five feature columns (inspiratory and expiratory tidal volume, minimum pressure, positive end-expiratory pressure, and previous positive end-expiratory pressure) and one output column (output column consisted of modes to be predicted). The data frame has been split into training and testing datasets with a test size of 30%. Six machine learning algorithms were trained and compared for performance, based on the accuracy, F1 score, sensitivity, and precision. The output shows that the Random-Forest Algorithm was the most precise and accurate in predicting all ventilation modes correctly, out of the all the machine learning algorithms trained. Thus, the Random-Forest machine learning technique can be utilized for predicting optimal ventilation mode setting, if it is properly trained with the help of the most relevant data. Aside from ventilation mode, control parameter settings, alarm settings and other settings may also be adjusted for the mechanical ventilation process utilizing appropriate machine learning, particularly deep learning approaches.

The effects of external diaphragmatic pacing on diaphragm function and weaning outcomes of critically ill patients with mechanical ventilation: a prospective randomized study.

Background: Diaphragmatic pacing can improve diaphragm function, which is beneficial for the prognosis of patients treated with prolonged mechanical ventilation (MV). While most previous studies have focused on the role of implanted diaphragm pacing (IDP), our study is the first to examine the effects of external diaphragmatic pacing (EDP) in mechanically ventilated patients. Specifically, the effect of EDP on diaphragm function, the success rate of weaning, the duration of MV (DMV), and the intensive care unit (ICU) length of stay (ILOS) were assessed. Methods: From September 2019 to December 2020, a total of 51 mechanically ventilated patients in the ICU of the Sun Yat-sen Memorial Hospital, Sun Yat-sen University were enrolled and randomly divided into an EDP group of 27 patients and a control group of 24 patients. The control group received routine treatment, and the EDP group received EDP treatment in addition to routine treatment. The diaphragm excursion (DE), diaphragm thickening fraction (DTF), DMV, ILOS, and average survival time were recorded to evaluate efficacy. Results: Patients treated with EDP had increased DE [exp(B) =1.86, 95% CI: 1.39 to 2.50, P<0.001] and DTF [exp(B) =1.35, 95% CI: 1.05 to 1.76, P=0.022], shortened weaning time (P=0.026) and prolonged average survival time (P<0.001) compared to patients who did not receive EDP therapy. Especially in cases with difficult weaning, the improvement of DE and DTF in the EDP treatment group was more obvious than that in the control group (P=0.013 and P=0.032). Moreover, the DTF upon attempted spontaneous breathing trial (SBT) was negatively correlated with the fraction of inspired oxygen (FiO2) [r=-0.54; 95% confidence interval (CI): -0.77 to -0.19; P=0.004], the arterial partial pressure of oxygen (PaO2) (r=-0.58; 95% CI: -0.79 to -0.25; P=0.001), the PaO2/FiO2 ratio (r=-0.52; 95% CI: -0.75 to -0.16; P=0.006), and the serum lactate concentration (Lac) (r=-0.39; 95% CI: -0.68 to 0.003; P=0.046). Conclusions: EDP treatment can effectively reduce the DMV and prolong the average survival time of mechanically ventilated patients. Trial Registration: Chinese Clinical Trial Registry ChiCTR1900024096.

Positive airway pressure longer than 24 h is associated with histopathological volutrauma in severe COVID-19 pneumonia-an ESGFOR based narrative case-control review.

Background and Objective: A thorough understanding of the pathogenic mechanisms elicited by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still requires further research. Until recently, only a restricted number of autopsies have been performed, therefore limiting the accurate knowledge of the lung injury associated with SARS-CoV-2. A multidisciplinary European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group of Forensic and Post-mortem Microbiology-ESGFOR team conducted a non-systematic narrative literature review among coronavirus 2019 disease (COVID-19) pneumonia cases assessing the histopathological (HP) effects of positive airways pressure. HP lung features were recorded and compared between mechanically ventilated (>24 hours) and control (ventilation <24 hours) patients. A logistic regression analysis was performed to identify associations between mechanical ventilation (MV) and HP findings. Methods: A PubMed and MEDLINE search was conducted in order to identify studies published between March 1st 2020 and June 30th 2021. Key Content and Findings: Seventy patients (median age: 69 years) from 24 studies were analysed, among whom 38 (54.2%) underwent MV longer than 24 hours. Overall, main HP features were: diffuse alveolar damage (DAD) in 53 (75.7%), fibrosis (interstitial/intra-alveolar) in 43 (61.4%), vascular damage-including thrombosis/emboli- in 41 (58.5%), and endotheliitis in only 8 (11.4%) patients. Association of DAD, fibrosis and vascular damage was detected in 30 (42.8%) patients. Multivariate analysis, adjusted by age and gender, identified MV >24 hours as an independent variable associated with DAD (OR =5.40, 95% CI: 1.48-19.62), fibrosis (OR =3.88, 95% CI: 1.25-12.08), vascular damage (OR =5.49, 95% CI: 1.78-16.95) and association of DAD plus fibrosis plus vascular damage (OR =6.99, 95% CI: 2.04-23.97). Conclusions: We identified that patients mechanically ventilated >24 hours had a significantly higher rate of pulmonary injury on histopathology independently of age and gender. Our findings emphasize the importance of maintaining a protective ventilator strategy when subjects with COVID-19 pneumonia undergo intubation.

Pneumonia is a common and early complication of the Severe Alcohol Withdrawal Syndrome (SAWS).

BACKGROUND: Pneumonia (PNA) may complicate the Severe Alcohol Withdrawal Syndrome (SAWS), with ICU admission, mechanical ventilation (MV), prolonged length of stay (LOS), and adverse events. OBJECTIVES: To examine the onset, features and courses of PNA in patients with SAWS to aid management. METHODS: A 33 month contiguous review of SAWS and PNA was conducted at an urban public hospital. RESULTS: There were 279 episodes of Alcohol Withdrawal Syndrome (AWS) among 255 patients. Males predominated (91%) with a mean age of 45.8 years (range 23-73), of whom 31% (87/279) developed SAWS with ICU management. Direct ICU admission occurred for 62 patients; 25 were transferred for delirium, seizures, escalating sedation, PNA or other complications. PNA was identified for 34 ICU direct admissions and 13 ward patients. Ten transfers to the ICU also developed PNA for an ICU total of 44/87 (51%), of whom 82% (36/44) required MV. Another 10 ICU patients without PNA received MV for high dose sedation or respiratory failure. Most ICU patients (72/87 (83%)), including all with MV, required IV infusion of sedation. MV prolonged LOS, but LOS for PNA with MV was similar to all MV. ICU transfers had longer LOS with greater use of MV than direct admits (p<0.05). PNA was identified before ICU admission or transfer for 73% (32/44 (p<0.05)), and usually before intubation. Most PNA was Community Acquired Pneumonia (CAP) with P. Pneumoniae frequently cultured. CONCLUSIONS: PNA with SAWS is predominately CAP and occurs early. Focused ICU admission with respiratory support are priorities of initial management.