Impact of prolonged assisted ventilation on diaphragmatic efficiency: NAVA versus PSV

Use of a Nutritional Risk Assessment Tool to Guide Early Enteral Nutrition among Mechanically Ventilated Trauma Patients

Background

The Modified Nutritional Risk in Critically Ill (mNUTRIC) score has been proposed as a tool to identify hospitalized patients at risk for malnutrition who may benefit from early enteral nutrition (EN) therapy.

Objective

Our goal was to determine if mNUTRIC scores could predict, at time of intensive care unit admission, which mechanically ventilated trauma patients were at risk for malnutrition and might benefit from early EN, as indicated by reduced mortality.

Methods

We conducted a retrospective chart review of all adult trauma patients requiring mechanical ventilation for at least 48 hours between 01/21/2012 and 12/31/2016, reviewing inpatient medical records, demographic data, disease markers, injury severity, and comorbidities. Bivariate statistics and multivariate regression analyses were used to investigate the correlation between time of EN initiation and mortality rates, as well as the relationship of mNUTRIC scores with EN commencement with early EN initiation being ≤48 hours and malnutrition risk mNUTRIC ≥5.

Results

Among 931 patients reviewed, bivariate analysis showed higher mNUTRIC scores correlated with older, sicker patients and higher mortality. However, multivariate analysis revealed no significant association between higher mNUTRIC scores and increased mortality (OR 1.2, 95% CI 0.7-2.1, p=0.52). Although most patients received EN within 48 hours, there was no association between mNUTRIC score and timing of EN initiation after adjusting for demographic variables and illness severity.

Conclusions

Our findings indicate that while the mNUTRIC score can effectively identify malnutrition risk, it does not meaningfully inform early EN initiation timing nor predict mortality in mechanically ventilated trauma patients.

Weakness acquired in the cardiac intensive care unit: still the elephant in the room?

Over the past two decades, the cardiac critical care population has shifted to increasingly comorbid and elderly patients often presenting with nonprimary cardiac conditions that exacerbate underlying advanced cardiac disease. Consequently, the modern cardiac intensive care unit (CICU) patient has poor outcome regardless of left ventricular ejection fraction. Importantly, delayed liberation from organ support, independent from premorbid health status and admission severity of illness, has been associated with increased morbidity and mortality up to years post-general critical care. Although a constellation of several acquired morbidities is at play, the most prominent enactor of poor long-term outcome in this population appears to be intensive care unit acquired weakness. Although the specific burden of ICU-acquired morbidities in CICU patients is yet to be clearly defined, it seems unfathomable that patients will not accrue some sort of ICU-related morbidity. There is hence an urgent need to better establish the exact benefit and cost of resource-intensive strategies in both short- and long-term survival of the CICU patient. Consequent and standardized documentation of admission comorbidities, severity of illness indicators, relevant ICU-related complications including weakness, and long-term post-ICU morbidity outcomes can help our understanding of the disease continuum and how to better care for the CICU survivor and their families and caregivers. Given increasing budgetary pressure on healthcare systems worldwide, interventions targeting CICU patients should focus on improving patient-centred long-term outcomes in a cost-effective manner. It will require a holistic and transmural continuity of care model to meet the challenges associated with treating critically ill cardiac patients in the future.

Proportional modes to hasten weaning

PURPOSE OF REVIEW

The purpose of this review is to examine the current state of the evidence, including several recent systematic reviews and meta-analyses, to determine if proportional modes of ventilation have the potential to hasten weaning from mechanical ventilation for adult critically ill patients, compared to pressure support ventilation (PSV), the current standard of care during the recovery and weaning phases of mechanical ventilation.

RECENT FINDINGS

Proportional assist ventilation (PAV) and neurally adjusted ventilatory assist (NAVA) are two commercially available proportional modes that have been studied in randomized controlled trials (RCTs). Although several feasibility studies were not powered to detect differences in clinical outcomes, emerging evidence suggests that both PAV and NAVA may reduce duration of mechanical ventilation, intensive care unit (ICU) length of stay, and hospital mortality compared to PSV, as shown in some small, primarily single-centre studies. Recent meta-analyses suggest that PAV shortens duration of mechanical ventilation and improves weaning success rate, and NAVA may reduce ICU and hospital mortality.

SUMMARY

The current state of the evidence suggests that proportional modes may hasten weaning from mechanical ventilation, but larger, multicentre RCTS are needed to confirm these preliminary findings.

Assessment of photobiomodulation in response to the microcirculation in arteriovenous fistula for hemodialysis patient

Background

Management of blood flow in arteriovenous fistula (AVF) is a critical clinical issue for hemodialysis (HD) patients.

Objectives

To determine the effect of microcirculation of AVF in HD patients with photobiomodulation (PBM).

Methods

Twenty HD patients were enrolled in this study. PBM was used to radiate the palm of HD patients at a total dose of 126 J, and the microcirculatory analysis in AVF was investigated.

Results

Among the patients <65 years old, there is an increase of 2.31% and 1.37% in the average velocity and flux in AVF, respectively. This increase is higher than those observed in patients aged >65 years old. Additionally, the cumulative effect of the 830 nm laser was observed for at least 10 min, resulting in continuous increases of 3.16% in velocity and 1.59% in flux for HD patients <65 years old. On the contrary, the average velocity and flux in AVF increased in patients who had undergone HD for <6 years.

Conclusions

In this study, the age and the duration of HD treatment are the two factors that influence microcirculation in HD patients with PBM. The results suggest that PBM could be used to improve the average velocity and flux in AVF, particularly for younger patients with shorter HD treatment durations.

A Bench Model of Asynchrony in 6 Ventilators Equipped With Waveform-Guided Options

Background: Pressure support ventilation is frequently associated with patient-ventilator asynchrony. Algorithms based on ventilator waveforms have been developed to automatically detect patient respiratory activity and to guide triggering and cycling. The aim of this study was to assess the performance in terms of synchronization of 6 mechanical ventilators, all provided with a waveform-guided software. Methods: This was a bench study to compare standard and new-generation systems simulating different respiratory mechanics, levels of assistance, and respiratory efforts. Six mechanical ventilators were tested: Hamilton G5 (G5) and C6 (C6), IMT bellavista1000 (B1000), Mindray SV300, and Philips RespironicsV200 (V200) and V60 (V60). Apart from V60, the other ventilators were tested twice: with default settings for standard triggering and cycling and with the waveform-guided automation. Results: With the automated settings, breaths with trigger delay ≤ 300 ms increased with B1000, G5, and C6. Ineffective efforts decreased with B1000, G5, C6, and V200. Improvement of triggering was mainly driven by findings obtained in the obstructive profile. With the automated settings, breaths with cycling delay > 300 ms decreased with B1000, G5, C6, and V200 while early cycled breaths increased with B1000. Improvement of cycling was mainly driven by findings obtained in the obstructive profile, whereas worsening of cycling was observed in the restrictive profile with 2 ventilators (B100 and V200). With the automated settings, the asynchrony index (AI) was reduced with G5 and C6 when all the profiles were grouped. In the obstructive profile, the AI decreased with B1000, G5, C6, and V200; in the restrictive profile, the AI increased with B1000. Conclusions: Waveforms-based algorithms have the potential to improve patient-ventilator synchronization. Automation had the most favorable impact when obstructive patients were simulated, while caution should be paid with restrictive ones.

Effectiveness of Anti-Inflammatory Agents to Prevent Atrial Fibrillation After Cardiac Surgery: A Systematic Review and Network Meta-Analysis

Background

Preventing postoperative atrial fibrillation (POAF) as one of the most significant complications of cardiovascular surgeries remains a major clinical challenge. We conducted a systematic review with network meta-analysis of randomized controlled trials, to identify the most effective and safe anti-inflammatory drugs to prevent new-onset POAF.

Methods

MEDLINE, Embase, Web of Science, and Cochrane Library were searched without language or publication-date restriction on August 8, 2022 (updated on August 8, 2023). We assessed the risk of bias of included trials using the Cochrane risk-of-bias 2.0 tool. We conducted a frequentist random-effects network meta-analysis in R, and we assessed the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach.

Results

A total of 85 trials reported the incidence of new-onset POAF, including 18,981 patients. Use of nonsteroidal anti-inflammatory drugs (relative risk [RR] 0.37 [95% confidence interval [CI] 0.23-0.59]) and statins (RR 0.56 [95% CI 0.45-0.7]) potentially reduced the risk of POAF compared with placebo (both with a moderate certainty level). Use of fish oil in combination with vitamins C and E (RR 0.30 [95% CI 0.13-0.68]) may reduce the risk of POAF, compared with placebo (low level of certainty). Use of colchicine (RR 0.62 [95% CI 0.45- 0.85]), corticosteroids (RR 0.70 [95% CI 0.59-0.82]), and N-acetylcysteine (RR 0.69 [95% CI 0.49- 0.98]) may reduce the risk of POAF (all with a low level of certainty). None of the interventions had a significant effect on mortality rate or risk of serious adverse effects.

Conclusions

Use of nonsteroidal anti-inflammatory drugs and statins probably are effective in preventing new-onset POAF, with a moderate level of certainty, compared to placebo.

Neurally Adjusted Ventilatory Assist to Monitor Diaphragmatic Activity in Infantile Botulism

Infantile botulism is a potentially life-threatening neuromuscular disorder. It presents with descending paralysis that can involve the diaphragm and cause respiratory failure. Neurally adjusted ventilatory assist (NAVA) provides synchronized bilevel positive pressure by using electrical diaphragmatic (Edi) signals. Diaphragmatic paresis is thought to be a contraindication for using NAVA. However, the use of a NAVA catheter allows continuous assessment of diaphragm activity in infantile botulism. We discuss a case of infantile botulism in an infant from central Pennsylvania who presented with poor oral feeding, hypothermia, and lethargy and progressed to develop apnea and acute respiratory failure. The infant was intubated and mechanically ventilated. A diagnosis of infantile botulism was confirmed through the detection of botulinum toxin in the infant's stool, and the infant was treated with botulism immune globulin neutralizing antibodies. During his recovery phase, a NAVA catheter was placed, which allowed monitoring of Edi signals to gauge the return of diaphragm activity and to assist with the assessment of extubation readiness. We describe the trends in this infant's Edi signals following administration of globulin neutralizing antibodies and the successful transition to invasive, and subsequently, noninvasive NAVA. Our report demonstrates the clinical utility of monitoring diaphragmatic activity using a NAVA catheter and that NAVA provided adequate respiratory support to an infant during the recovery phase of infantile botulism.

Respiratory Drive, Effort, and Lung-Distending Pressure during Transitioning from Controlled to Spontaneous Assisted Ventilation in Patients with ARDS: A Multicenter Prospective Cohort Study

Objectives: To investigate the impact of patient characteristics and treatment factors on excessive respiratory drive, effort, and lung-distending pressure during transitioning from controlled to spontaneous assisted ventilation in patients with acute respiratory distress syndrome (ARDS). Methods: Multicenter cohort observational study of patients with ARDS at four academic intensive care units. Respiratory drive (P0.1), diaphragm electrical activity (EAdi), inspiratory effort derived from EAdi (∆PmusEAdi) and from occlusion of airway pressure (∆Pocc) (PmusΔPocc), and dynamic transpulmonary driving pressure (ΔPL,dyn) were measured at the first transition to assisted spontaneous breathing. Results: A total of 4171 breaths were analyzed in 48 patients. P0.1 was >3.5 cmH2O in 10%, EAdiPEAK > 15 µV in 29%, ∆PmusEAdi > 15 cmH2O in 28%, and ΔPL,dyn > 15 cmH2O in 60% of the studied breaths. COVID-19 etiology of ARDS was the strongest independent risk factor for a higher proportion of breaths with excessive respiratory drive (RR 3.00 [2.43-3.71], p < 0.0001), inspiratory effort (RR 1.84 [1.58-2.15], p < 0.0001), and transpulmonary driving pressure (RR 1.48 [1.36-1.62], p < 0.0001). The P/F ratio at ICU admission, days of deep sedation, and dose of steroids were additional risk factors for vigorous inspiratory effort. Age and dose of steroids were risk factors for high transpulmonary driving pressure. Days of deep sedation (aHR 1.15 [1.07-1.24], p = 0.0002) and COVID-19 diagnosis (aHR 6.96 [1-48.5], p = 0.05) of ARDS were independently associated with composite outcome of transitioning from light to deep sedation (RASS from 0/-3 to -4/-5) or return to controlled ventilation within 48 h of spontaneous assisted breathing. Conclusions: This study identified that specific patient characteristics, including age, COVID-19-related ARDS, and P/F ratio, along with treatment factors such as the duration of deep sedation and the dosage of steroids, are independently associated with an increased likelihood of assisted breaths reaching potentially harmful thresholds of drive, effort, and lung-distending pressure during the initial transition to spontaneous assisted breathing. It is noteworthy that patients who were subjected to prolonged deep sedation under controlled mechanical ventilation, as well as those with COVID-19, were more susceptible to failing the transition from controlled to assisted breathing.

Risks for prolonged mechanical ventilation and reintubation after cervical malignant tumor surgery: a nested case-control study

PURPOSE

Prolonged mechanical ventilation (PMV) and reintubation are among the most serious postoperative adverse events associated with malignant cervical tumors. In this study, we aimed to clarify the incidence, characteristics, and risk factors for PMV and reintubation in target patients.

METHODS

This retrospective nested case-control study was performed between January 2014 and January 2020 at a large spinal tumor center in China. Univariate analysis was used to identify the possible risk factors associated with PMV and reintubation. Logistic regression analysis was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) with covariates of a probability < 0.05 in univariate analysis.

RESULTS

From a cohort of 560 patients with primary malignant (n = 352) and metastatic (n = 208) cervical tumors, 27 patients required PMV and 20 patients underwent reintubation. The incidence rates of PMV and reintubation were 4.82% and 3.57%, respectively. Three variables (all p < 0.05) were independently associated with an increased risk of PMV: Karnofsky Performance Status < 50 compared to ≥ 80, operation duration ≥ 8 h compared to < 6 h, and C4 nerve root encased by the tumor. Longer operative duration and preoperative hypercapnia (all p < 0.05) were independent risk factors for postoperative reintubation, both of which led to longer length of stay (32.6 ± 30.8 vs. 10.7 ± 5.95 days, p < 0.001), with an in-hospital mortality of 17.0%.

CONCLUSION

Our results demonstrate the risk factors for PMV or reintubation after surgery for malignant cervical tumors. Adequate assessment, early detection, and prevention are necessary for this high-risk population.

An orally administered bacterial membrane protein nanodrug ameliorates doxorubicin cardiotoxicity through alleviating impaired intestinal barrier

The cardiotoxicity caused by Dox chemotherapy represents a significant limitation to its clinical application and is a major cause of late death in patients undergoing chemotherapy. Currently, there are no effective treatments available. Our analysis of 295 clinical samples from 132 chemotherapy patients and 163 individuals undergoing physical examination revealed a strong positive correlation between intestinal barrier injury and the development of cardiotoxicity in chemotherapy patients. We developed a novel orally available and intestinal targeting protein nanodrug by assembling membrane protein Amuc_1100 (obtained from intestinal bacteria Akkermansia muciniphila), fluorinated polyetherimide, and hyaluronic acid. The protein nanodrug demonstrated favorable stability against hydrolysis compared with free Amuc_1100. The in vivo results demonstrated that the protein nanodrug can alleviate Dox-induced cardiac toxicity by improving gut microbiota, increasing the proportion of short-chain fatty acid-producing bacteria from the Lachnospiraceae family, and further enhancing the levels of butyrate and pentanoic acids, ultimately regulating the homeostasis repair of lymphocytes in the spleen and heart. Therefore, we believe that the integrity of the intestinal barrier plays an important role in the development of chemotherapy-induced cardiotoxicity. Protective interventions targeting the intestinal barrier may hold promise as a general clinical treatment regimen for reducing Dox-induced cardiotoxicity.

Resveratrol-Ampicillin Dual-Drug Loaded Polyvinylpyrrolidone/Polyvinyl Alcohol Biomimic Electrospun Nanofiber Enriched with Collagen for Efficient Burn Wound Repair

Background

The healing of burn wounds is a complicated physiological process that involves several stages, including haemostasis, inflammation, proliferation, and remodelling to rebuild the skin and subcutaneous tissue integrity. Recent advancements in nanomaterials, especially nanofibers, have opened a new way for efficient healing of wounds due to burning or other injuries.

Methods

This study aims to develop and characterize collagen-decorated, bilayered electrospun nanofibrous mats composed of PVP and PVA loaded with Resveratrol (RSV) and Ampicillin (AMP) to accelerate burn wound healing and tissue repair.

Results

Nanofibers with smooth surfaces and web-like structures with diameters ranging from 200 to 400 nm were successfully produced by electrospinning. These fibres exhibited excellent in vitro properties, including the ability to absorb wound exudates and undergo biodegradation over a two-week period. Additionally, these nanofibers demonstrated sustained and controlled release of encapsulated Resveratrol (RSV) and Ampicillin (AMP) through in vitro release studies. The zone of inhibition (ZOI) of PVP-PVA-RSV-AMP nanofibers against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was found 31±0.09 mm and 12±0.03, respectively, which was significantly higher as compared to positive control. Similarly, the biofilm study confirmed the significant reduction in the formation of biofilms in nanofiber-treated group against both S. aureus and E. coli. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis proved the encapsulation of RSV and AMP successfully into nanofibers and their compatibility. Haemolysis assay (%) showed no significant haemolysis (less than 5%) in nanofiber-treated groups, confirmed their cytocompatibility with red blood cells (RBCs). Cell viability assay and cell adhesion on HaCaT cells showed increased cell proliferation, indicating its biocompatibility as well as non-toxic properties. Results of the in-vivo experiments on a burn wound model demonstrated potential burn wound healing in rats confirmed by H&E-stained images and also improved the collagen synthesis in nanofibers-treated groups evidenced by Masson-trichrome staining. The ELISA assay clearly indicated the efficient downregulation of TNF-alpha and IL-6 inflammatory biomarkers after treatment with nanofibers on day 10.

Conclusion

The RSV and AMP-loaded nanofiber mats, developed in this study, expedite burn wound healing through their multifaceted approach.

The effectiveness of probiotics as an adjunct therapy in patients under mechanical ventilation: an umbrella systematic review and meta-analysis

The literature regarding the role of probiotics in critically ill patients who have undergone mechanical ventilation (MV) is unclear; therefore, this umbrella systematic review and meta-analysis was carried out to clarify the effects of probiotics on the clinical outcomes of mechanically ventilated patients. The Scopus, PubMed/Medline, ISI Web of Science, and Google Scholar online databases were searched up to February 2023. All meta-analyses evaluating the impact of probiotics in patients under MV were considered eligible. The assessment of multiple systematic reviews (AMSTAR) questionnaire was used to evaluate the quality of the studies. Data were pooled using the random-effects approach. Thirty meta-analyses and nine clinical outcomes were re-analyzed. Probiotics significantly decreased ventilator-associated pneumonia (VAP) incidence, nosocomial infections, intensive care unit (ICU) length of stay, hospital length of stay, ICU mortality, hospital mortality, MV duration, duration of antibiotic use, and diarrhea. The obtained results of the current umbrella meta-analysis indicate that probiotic administration could be considered an adjunct therapy for critically ill patients; however, no specific probiotic treatment regimen can be recommended due to the diverse probiotics used in the included meta-analyses. The following microorganisms were used at various doses and combinations throughout the studies: Lacticaseibacillus casei, Lactiplantibacillus plantarum, L. acidophilus, L. delbrueckii, L. bulgaricus, Bifidobacterium longum, B. breve, B. salivarius, Pediococcus pentosaceus, Lactococcus raffinolactis, B. infantis, B. bifidum, Streptococcus thermophilus, Ligilactobacillus salivarius, L. lactis, B. lactis, Saccharomyces boulardii, L. rhamnosus GG, L. johnsonii, L. casei, S. faecalis, Clostridium butyricum, Bacillus mesentericus, L. sporogenes, S. boulardii, L. paracasei, B. subtilis, and Enterococcus faecium.

Advanced Respiratory Monitoring during Extracorporeal Membrane Oxygenation

Advanced respiratory monitoring encompasses a diverse range of mini- or noninvasive tools used to evaluate various aspects of respiratory function in patients experiencing acute respiratory failure, including those requiring extracorporeal membrane oxygenation (ECMO) support. Among these techniques, key modalities include esophageal pressure measurement (including derived pressures), lung and respiratory muscle ultrasounds, electrical impedance tomography, the monitoring of diaphragm electrical activity, and assessment of flow index. These tools play a critical role in assessing essential parameters such as lung recruitment and overdistention, lung aeration and morphology, ventilation/perfusion distribution, inspiratory effort, respiratory drive, respiratory muscle contraction, and patient-ventilator synchrony. In contrast to conventional methods, advanced respiratory monitoring offers a deeper understanding of pathological changes in lung aeration caused by underlying diseases. Moreover, it allows for meticulous tracking of responses to therapeutic interventions, aiding in the development of personalized respiratory support strategies aimed at preserving lung function and respiratory muscle integrity. The integration of advanced respiratory monitoring represents a significant advancement in the clinical management of acute respiratory failure. It serves as a cornerstone in scenarios where treatment strategies rely on tailored approaches, empowering clinicians to make informed decisions about intervention selection and adjustment. By enabling real-time assessment and modification of respiratory support, advanced monitoring not only optimizes care for patients with acute respiratory distress syndrome but also contributes to improved outcomes and enhanced patient safety.

Dyssynchronous diaphragm contractions impair diaphragm function in mechanically ventilated patients

BACKGROUND

Pre-clinical studies suggest that dyssynchronous diaphragm contractions during mechanical ventilation may cause acute diaphragm dysfunction. We aimed to describe the variability in diaphragm contractile loading conditions during mechanical ventilation and to establish whether dyssynchronous diaphragm contractions are associated with the development of impaired diaphragm dysfunction.

METHODS

In patients receiving invasive mechanical ventilation for pneumonia, septic shock, acute respiratory distress syndrome, or acute brain injury, airway flow and pressure and diaphragm electrical activity (Edi) were recorded hourly around the clock for up to 7 days. Dyssynchronous post-inspiratory diaphragm loading was defined based on the duration of neural inspiration after expiratory cycling of the ventilator. Diaphragm function was assessed on a daily basis by neuromuscular coupling (NMC, the ratio of transdiaphragmatic pressure to diaphragm electrical activity).

RESULTS

A total of 4508 hourly recordings were collected in 45 patients. Edi was low or absent (≤ 5 µV) in 51% of study hours (median 71 h per patient, interquartile range 39-101 h). Dyssynchronous post-inspiratory loading was present in 13% of study hours (median 7 h per patient, interquartile range 2-22 h). The probability of dyssynchronous post-inspiratory loading was increased with reverse triggering (odds ratio 15, 95% CI 8-35) and premature cycling (odds ratio 8, 95% CI 6-10). The duration and magnitude of dyssynchronous post-inspiratory loading were associated with a progressive decline in diaphragm NMC (p < 0.01 for interaction with time).

CONCLUSIONS

Dyssynchronous diaphragm contractions may impair diaphragm function during mechanical ventilation.

TRIAL REGISTRATION

MYOTRAUMA, ClinicalTrials.gov NCT03108118. Registered 04 April 2017 (retrospectively registered).

Rapid review of ventilator-induced diaphragm dysfunction

Ventilator-induced diaphragm dysfunction is gaining increased recognition. Evidence of diaphragm weakness can manifest within 12 h to a few days after the initiation of mechanical ventilation. Various noninvasive and invasive methods have been developed to assess diaphragm function. The implementation of diaphragm-protective ventilation strategies is crucial for preventing diaphragm injuries. Furthermore, diaphragm neurostimulation emerges as a promising and novel treatment option. In this rapid review, our objective is to discuss the current understanding of ventilator-induced diaphragm dysfunction, diagnostic approaches, and updates on strategies for prevention and management.

Trends in the Incidence of Bronchopulmonary Dysplasia after the Introduction of Neurally Adjusted Ventilatory Assist (NAVA)

OBJECTIVE

This study investigates the difference in the rates of bronchopulmonary dysplasia in very low birth weight infants before and after the introduction of neurally adjusted ventilatory assist (NAVA).

STUDY DESIGN

A retrospective cohort study comparing rates of Bronchopulmonary dysplasia (BPD) before and after implementation of NAVA. Eligibility criteria included all very low birth weight VLBW neonates needing ventilation. For analysis, each cohort was divided into three subgroups based on gestational age. Changes in the rate of BPD, length of stay, tracheostomy rates, invasive ventilator days, and home oxygen therapy were compared.

RESULTS

There were no differences in the incidence of BPD in neonates at 23-25 6/7 weeks' and 29-32 weeks' gestation between the two cohorts. A higher incidence of BPD was seen in the 26-28 5/7 weeks' gestation NAVA subgroup compared to controls (86% vs. 68%, p = 0.05). No significant difference was found for ventilator days, but infants in the 26-28 6/7 subgroup in the NAVA cohort had a longer length of stay (98 ± 34 days vs. 82 ± 24 days, p = 0.02), a higher percentage discharged on home oxygen therapy (45% vs. 18%, respectively, p = 0.006), and higher tracheostomy rates (3/36 vs. 0/60, p = 0.02), compared to the control group.

CONCLUSIONS

The NAVA mode was not associated with a reduction in BPD when compared to other modes of ventilation. Unexpected increases were seen in BPD rates, home oxygen therapy rates, tracheostomy rates, and the length of stay in the NAVA subgroup born at 26-28 6/7 weeks' gestation.

The value of right ventricular to pulmonary arterial coupling in the critically ill: a National Echocardiography Database of Australia (NEDA) substudy

BACKGROUND

Right ventricular (RV) function is tightly coupled to afterload, yet echocardiographic indices of RV function are frequently assessed in isolation. Normalizing RV function for afterload (RV-PA coupling) using a simplified ratio of tricuspid annular plane systolic excursion (TAPSE)/ tricuspid regurgitant velocity (TRV) could help to identify RV decompensation and improve risk stratification in critically ill patients. This is the first study to explore the distribution of TAPSE/TRV ratio and its prognostic relevance in a large general critical care cohort.

METHODS

We undertook retrospective analysis of echocardiographic, clinical, and mortality data of intensive care unit (ICU) patients between January 2012 and May 2017. A total of 1077 patients were included and stratified into tertile groups based on TAPSE/TRV ratio: low (< 5.9 mm.(m/s)-1), middle (≥ 5.9-8.02 mm.(m/s)-1), and high (≥ 8.03 mm.(m/s)-1). The distribution of the TAPSE/TRV ratio across ventricular function subtypes of normal, isolated left ventricular (LV), isolated RV, and biventricular dysfunction was explored. The overall prognostic relevance of the TAPSE/TRV ratio was tested, including distribution across septic, cardiovascular, respiratory, and neurological subgroups.

RESULTS

Higher proportions of ventricular dysfunctions were seen in low TAPSE/TRV tertiles. TAPSE/TRV ratio is impacted by LV systolic function but to a lesser extent than RV dysfunction or biventricular dysfunction. There was a strong inverse relationship between TAPSE/TRV ratio and survival. After multivariate analysis, higher TAPSE/TRV ratios (indicating better RV-PA coupling) were independently associated with lower risk of death in ICU (HR 0.927 [0.872-0.985], p < 0.05). Kaplan-Meier analysis demonstrated higher overall survival in middle and high tertiles compared to low tertiles (log rank p < 0.0001). The prognostic relevance of TAPSE/TRV ratio was strongest in respiratory and sepsis subgroups. Patients with TAPSE/TRV < 5.9 mm (m/s)-1 had a significantly worse prognosis than those with higher TAPSE/TRV ratios.

CONCLUSION

The TAPSE/TRV ratio has prognostic relevance in critically ill patients. The prognostic power may be stronger in respiratory and septic subgroups. Larger prospective studies are needed to investigate the role of TAPSE/TRV in pre-specified subgroups including its role in clinical decision-making.

The predictive value of neurally adjusted ventilatory assist indexes for the prognosis of patients with severe cerebral hemorrhage

OBJECTIVE

This study assessed the predictive value of electrical activity of the diaphragm (EAdi) and the EAdi-derived monitoring index in the prognosis of patients with severe cerebral hemorrhage.

METHODS

Ninety patients with severe cerebral hemorrhage were admitted to the Neurosurgery Intensive Care Unit of Yijishan Hospital from April 2019 to June 2021 and were divided into the good prognosis group (Glasgow Outcome Scale [GOS] ≥ 4) and poor prognosis group (GOS ≤ 3). The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate prediction accuracy.

RESULTS

EAdi, neuro-ventilatory efficiency (NVE), and neuro-muscular efficiency (NME) in patients with good prognosis were significantly higher than those in patients with poor prognosis (4.707 µV vs 2.80 µV, P < 0.001; 141.85 ml/µV vs 66.01 ml/µV, P = 0.000; 2.57 cm H2O/µV vs 1.37 cm H2O/µV, P = 0.000). The area under the ROC curve for the EAdi score was 0.719, with sensitivity of 69.70% and specificity of 68.42% when EAdi was 3.6 µV. The AUC for NVE score was 0.793, with sensitivity of 75.76% and specificity of 75.44% when the NVE value was 95.32 ml/µV. The AUC for NME score was 0.792, with sensitivity of 69.70% and specificity of 78.95% when the NME value was 2.06 H2O/µV. The 6-month survival time of patients with higher EAdi, NVE, and NME was significantly longer than that of patients with lower EAdi, NVE, and NME CONCLUSION: EAdi, NVE, and NME can be used as indices for predicting the prognosis of patients with severe cerebral hemorrhage.

TRIAL REGISTRATION NO

ChiCTR1900022861. Registered April 28, 2019, http://www.chictr.org.cn .

Pendelluft in hypoxemic patients resuming spontaneous breathing: proportional modes versus pressure support ventilation

BACKGROUND

Internal redistribution of gas, referred to as pendelluft, is a new potential mechanism of effort-dependent lung injury. Neurally-adjusted ventilatory assist (NAVA) and proportional assist ventilation (PAV +) follow the patient's respiratory effort and improve synchrony compared with pressure support ventilation (PSV). Whether these modes could prevent the development of pendelluft compared with PSV is unknown. We aimed to compare pendelluft magnitude during PAV + and NAVA versus PSV in patients with resolving acute respiratory distress syndrome (ARDS).

METHODS

Patients received either NAVA, PAV + , or PSV in a crossover trial for 20-min using comparable assistance levels after controlled ventilation (> 72 h). We assessed pendelluft (the percentage of lost volume from the non-dependent lung region displaced to the dependent region during inspiration), drive (as the delta esophageal swing of the first 100 ms [ΔPes 100 ms]) and inspiratory effort (as the esophageal pressure-time product per minute [PTPmin]). We performed repeated measures analysis with post-hoc tests and mixed-effects models.

RESULTS

Twenty patients mechanically ventilated for 9 [5-14] days were monitored. Despite matching for a similar tidal volume, respiratory drive and inspiratory effort were slightly higher with NAVA and PAV + compared with PSV (ΔPes 100 ms of -2.8 [-3.8--1.9] cm H2O, -3.6 [-3.9--2.4] cm H2O and -2.1 [-2.5--1.1] cm H2O, respectively, p < 0.001 for both comparisons; PTPmin of 155 [118-209] cm H2O s/min, 197 [145-269] cm H2O s/min, and 134 [93-169] cm H2O s/min, respectively, p < 0.001 for both comparisons). Pendelluft magnitude was higher in NAVA (12 ± 7%) and PAV + (13 ± 7%) compared with PSV (8 ± 6%), p < 0.001. Pendelluft magnitude was strongly associated with respiratory drive (β = -2.771, p-value < 0.001) and inspiratory effort (β = 0.026, p  < 0.001), independent of the ventilatory mode. A higher magnitude of pendelluft in proportional modes compared with PSV existed after adjusting for PTPmin (β = 2.606, p = 0.010 for NAVA, and β = 3.360, p = 0.004 for PAV +), and only for PAV + when adjusted for respiratory drive (β = 2.643, p = 0.009 for PAV +).

CONCLUSIONS

Pendelluft magnitude is associated with respiratory drive and inspiratory effort. Proportional modes do not prevent its occurrence in resolving ARDS compared with PSV.

Neurally Adjusted Ventilatory Assist Versus Pressure Support Ventilation: A Comprehensive Review

Mechanical ventilation serves as crucial life support for critically ill patients. Although it is life-saving prolonged ventilation carries risks and complications like barotrauma, Ventilator-associated pneumonia, sepsis, and many others. Optimizing patient-ventilator interactions and facilitating early weaning is necessary for improved intensive care unit (ICU) outcomes. Traditionally Pressure support ventilation (PSV) mode is widely used for weaning patients who are intubated and mechanically ventilated. Neurally adjusted ventilatory assist (NAVA) mode of the ventilator is an emerging ventilator mode that delivers pressure depending on the patient's respiratory drive, which in turn prevents over-inflation and improves the patient's ventilator interactions. Our article revises and compares the effectiveness of NAVA compared to PSV ventilation under different contexts. Overall we conclude that NAVA level of ventilation can be safely administered in a patient with acute respiratory failure, provided diaphragmatic paralysis is not considered. NAVA improves asynchrony index, wean-off time, and sleep quality and is associated with increased ventilator-free days. These results are based on small-scale studies with low power, and further studies are warranted in large-scale cohorts with more diverse populations to confirm these results.

Comparison of clinical outcomes in critical patients undergoing different mechanical ventilation modes: a systematic review and network meta-analysis

Purpose

To evaluate the effects of different mechanical ventilation modes on critical patients.

Methods

PubMed, Embase, Web of science, and Cochrane Library databases were searched from their inception to November 15, 2022 for randomized controlled trials on the application of different mechanical ventilation modes in critical patients. Two researchers independently screened the literature, extracted data, and assessed the risk of bias in the included studies. R4.2.1 was used for this network meta-analysis.

Results

Twenty-eight RCTs involving 3,189 patients were included. The interventions in these RCTs included NAVA (neurally adjusted ventilatory assist), PAV (proportional assist ventilation), ASV (adaptive support ventilation), Smartcare/PS (Smartcare/pressure support), PSV (pressure support ventilation), PSV_ATC (pressure support ventilation_automatic tube compensation), and SIMV (synchronized intermittent mandatory ventilation). The network meta-analysis showed that, compared with the PSV group, there was no significant difference in duration of mechanical ventilation, duration of ICU stay, and hospital stay between NAVA, SIMV, AVS, PAV, Smartcare/PS, and PSV_ATC groups. Compared with PSV, PAV improved the success rate of withdrawal of ventilator [OR = 3.07, 95%CI (1.21, 8.52)]. Compared with PSV and PAV, NAVA reduced mortality in the ICU [OR = 0.63, 95%CI (0.43, 0.93); OR = 0.45, 95%CI (0.21, 0.97)].

Conclusion

NAVA can reduce mortality in ICU, and PAV may increase the risk of withdrawal of the ventilator. There was no significant difference between PSV and other mechanical ventilation modes (NAVA, SIMV, AVS, PAV, Smartcare/PS, and PSV_ATC) in the duration of mechanical ventilation, duration of ICU stay, or hospital stay. Due to the limitations, more high-quality studies are needed to verify these findings.

Retained Metabolic Flexibility of the Failing Human Heart

BACKGROUND

The failing heart is traditionally described as metabolically inflexible and oxygen starved, causing energetic deficit and contractile dysfunction. Current metabolic modulator therapies aim to increase glucose oxidation to increase oxygen efficiency of adenosine triphosphate production, with mixed results.

METHODS

To investigate metabolic flexibility and oxygen delivery in the failing heart, 20 patients with nonischemic heart failure with reduced ejection fraction (left ventricular ejection fraction 34.9±9.1) underwent separate infusions of insulin+glucose infusion (I+G) or Intralipid infusion. We used cardiovascular magnetic resonance to assess cardiac function and measured energetics using phosphorus-31 magnetic resonance spectroscopy. To investigate the effects of these infusions on cardiac substrate use, function, and myocardial oxygen uptake (MVo2), invasive arteriovenous sampling and pressure-volume loops were performed (n=9).

RESULTS

At rest, we found that the heart had considerable metabolic flexibility. During I+G, cardiac glucose uptake and oxidation were predominant (70±14% total energy substrate for adenosine triphosphate production versus 17±16% for Intralipid; P=0.002); however, no change in cardiac function was seen relative to basal conditions. In contrast, during Intralipid infusion, cardiac long-chain fatty acid (LCFA) delivery, uptake, LCFA acylcarnitine production, and fatty acid oxidation were all increased (LCFA 73±17% of total substrate versus 19±26% total during I+G; P=0.009). Myocardial energetics were better with Intralipid compared with I+G (phosphocreatine/adenosine triphosphate 1.86±0.25 versus 2.01±0.33; P=0.02), and systolic and diastolic function were improved (LVEF 34.9±9.1 baseline, 33.7±8.2 I+G, 39.9±9.3 Intralipid; P<0.001). During increased cardiac workload, LCFA uptake and oxidation were again increased during both infusions. There was no evidence of systolic dysfunction or lactate efflux at 65% maximal heart rate, suggesting that a metabolic switch to fat did not cause clinically meaningful ischemic metabolism.

CONCLUSIONS

Our findings show that even in nonischemic heart failure with reduced ejection fraction with severely impaired systolic function, significant cardiac metabolic flexibility is retained, including the ability to alter substrate use to match both arterial supply and changes in workload. Increasing LCFA uptake and oxidation is associated with improved myocardial energetics and contractility. Together, these findings challenge aspects of the rationale underlying existing metabolic therapies for heart failure and suggest that strategies promoting fatty acid oxidation may form the basis for future therapies.

Mechanical ventilation in patients with acute respiratory distress syndrome: current status and future perspectives

INTRODUCTION

Although there has been extensive research on mechanical ventilation for acute respiratory distress syndrome (ARDS), treatment remains mainly supportive. Recent studies and new ventilatory modes have been proposed to manage patients with ARDS; however, the clinical impact of these strategies remains uncertain and not clearly supported by guidelines. The aim of this narrative review is to provide an overview and update on ventilatory management for patients with ARDS.

AREAS COVERED

This article reviews the literature regarding mechanical ventilation in ARDS. A comprehensive overview of the principal settings for the ventilator parameters involved is provided as well as a report on the differences between controlled and assisted ventilation. Additionally, new modes of assisted ventilation are presented and discussed. The evidence concerning rescue strategies, including recruitment maneuvers and extracorporeal membrane oxygenation support, is analyzed. PubMed, EBSCO, and the Cochrane Library were searched up until June 2023, for relevant literature.

EXPERT OPINION

Available evidence for mechanical ventilation in cases of ARDS suggests the use of a personalized mechanical ventilation strategy. Although promising, new modes of assisted mechanical ventilation are still under investigation and guidelines do not recommend rescue strategies as the standard of care. Further research on this topic is required.

Advanced Point-of-care Bedside Monitoring for Acute Respiratory Failure

Advanced respiratory monitoring involves several mini- or noninvasive tools, applicable at bedside, focused on assessing lung aeration and morphology, lung recruitment and overdistention, ventilation-perfusion distribution, inspiratory effort, respiratory drive, respiratory muscle contraction, and patient-ventilator asynchrony, in dealing with acute respiratory failure. Compared to a conventional approach, advanced respiratory monitoring has the potential to provide more insights into the pathologic modifications of lung aeration induced by the underlying disease, follow the response to therapies, and support clinicians in setting up a respiratory support strategy aimed at protecting the lung and respiratory muscles. Thus, in the clinical management of the acute respiratory failure, advanced respiratory monitoring could play a key role when a therapeutic strategy, relying on individualization of the treatments, is adopted.

Closed-loop ventilation

PURPOSE OF REVIEW

The last 25 years have seen considerable development in modes of closed-loop ventilation and there are now several of them commercially available. They not only offer potential benefits for the individual patient, but may also improve the organization within the intensive care unit (ICU). Clinicians are showing both greater interest and willingness to address the issues of a caregiver shortage and overload of bedside work in the ICU. This article reviews the clinical benefits of using closed-loop ventilation modes, with a focus on control of oxygenation, lung protection, and weaning.

RECENT FINDINGS

Closed-loop ventilation modes are able to maintain important physiological variables, such as oxygen saturation measured by pulse oximetry, tidal volume (VT), driving pressure (ΔP), and mechanical power (MP), within target ranges aimed at ensuring continuous lung protection. In addition, these modes adapt the ventilator support to the patient's needs, promoting diaphragm activity and preventing over-assistance. Some studies have shown the potential of these modes to reduce the duration of both weaning and mechanical ventilation.

SUMMARY

Recent studies have primarily demonstrated the safety, efficacy, and feasibility of using closed-loop ventilation modes in the ICU and postsurgery patients. Large, multicenter randomized controlled trials are needed to assess their impact on important short- and long-term clinical outcomes, the organization of the ICU, and cost-effectiveness.

Patient-Ventilator Synchrony

Patient-ventilator asynchrony develops when the ventilator output does not match the efforts of the patient and contributes to excess work of breathing, lung injury, and mortality. Asynchronies are categorized as trigger (breath initiation), flow (delivery of the breath), and cycle (transition from inspiration to expiration). Clinicians should be skilled at ventilator waveform analysis to detect patient-ventilator asynchronies and make informed ventilator adjustments. Ventilator overdrive suppresses respiratory drive and reduces asynchrony, while other adjustments specific to the asynchrony are also useful.

Predictive Factors of Outcome in Cases of Out-of-hospital Cardiac Arrest Due to Traffic Accident Injuries in Thailand; a National Database Study

INTRODUCTION

Traffic accident injury is one of the global leading causes of death and an important public health problem. This study aimed to evaluate the predictive factors of return of spontaneous circulation (ROSC) at the scene in out-of-hospital cardiac arrest (OHCA) due to traffic accidents.

METHODS

This retrospective cross-sectional study was conducted on cases of OHCA due to traffic accident, who were resuscitated at the scene by emergency medical services (EMS) in Bankok, Thiland, from January 1, 2020, to December 31, 2020 (1 year). Patients were divided into two groups of with and without ROSC and independent predictive factors of outcome were evaluated.

RESULTS

2400 OHCA cases met the inclusion criteria, among them, 1728 (72.0%) achieved ROSC at the scene. Facial injury (adjusted OR = 2.17, 95%CI: 1.37-3.44, p = 0.001); prehospital airway management using bag valve mask (adjusted OR = 1.69, 95%CI: 1.21-2.34, p = 0.002), and endotracheal tube (adjusted OR = 3.88, 95%CI: 1.84-8.18, p <0.001); and prehospital fluid therapy using normal saline (adjusted OR = 4.24, 95%CI: 3.12-5.77, p <0.001), ringer lactate (adjusted OR = 5.13, 95%CI: 3.47-7.61, p <0.001), and other solutions (adjusted OR = 5.25, 95%CI: 2.16-12.8, p <0.001) were independent predictive factors of ROSC at the scene in OHCA due to traffic accidents.

CONCLUSION

Based on the findings, the rate of ROSC at the scene for cases with OHCA due to traffic accidents, serviced by EMS was high, i.e., 72%, and three independent predictive factors of ROSC at the scene were facial injury, prehospital airway management, and prehospital fluid management.

Liberation from Mechanical Ventilation: Established and New Insights

A substantial proportion of critically ill patients require ventilator support with the majority requiring invasive mechanical ventilation. Timely and safe liberation from invasive mechanical ventilation is a critical aspect of patient care in the intensive care unit (ICU) and is a top research priority for patients and clinicians. In this article, we discuss how to (1) identify candidates for liberation from mechanical ventilation, (2) conduct spontaneous breathing trials (SBTs), and (3) optimize patients for liberation from mechanical ventilation. We also discuss the roles for (4) extubation to noninvasive ventilation and (5) newer modes of mechanical ventilation during liberation from mechanical ventilation. We conclude that, though substantial progress has been made in identifying patients who are likely to be liberated (e.g., through the use of SBTs) and management strategies that speed liberation from the ventilator (e.g., protocolized SBTs, lighter sedation, and early mobilization), many important questions regarding liberation from mechanical ventilation in clinical practice remain unanswered.

Patient-Ventilator Synchrony in Neurally-Adjusted Ventilatory Assist and Variable Pressure Support Ventilation

BACKGROUND

Neurally-adjusted ventilatory assist (NAVA) improves patient-ventilator synchrony and reduces the risk of respiratory over-assistance. Variable pressure support ventilation (PSV) is a recently introduced mode of assisted ventilation that has also shown reduction in patient-ventilator asynchronies. We hypothesized that NAVA would reduce patient-ventilator asynchronies and inspiratory effort compared to variable PSV because breathing variability was intrinsically determined by the patient and not by the ventilator. This study aimed to evaluate patient-ventilator asynchronies and inspiratory effort pressure-time product (PTP) between NAVA and variable PSV in subjects with mild ARDS.

METHODS

After 24 h of controlled mechanical ventilation, subjects (P_aO2 /F_IO2 200-300 and PEEP level < 10 cm H₂O) were randomized in sequence 1:1 by using a web-based encrypted platform and assigned to NAVA or variable PSV groups. Both modes of ventilation were consecutively kept for 24 h unless there were clinical changes. The primary aim of this study was to evaluate differences in asynchrony index (AI) between variable PSV and NAVA. Our secondary aims were to evaluate the coefficient of variation (CV) of breathing patterns and inspiratory effort between the groups.

RESULTS

Thirteen subjects were randomized in the NAVA group and 13 subjects in the variable PSV group. AI over time and minute PTP (PTP_min) were not different between NAVA and variable PSV groups (AI t₀P = .52, AI t₁₂P = .27, AI t₂₄P = .12; and PTP_min-t0P = .60, PTP_min-t12P = .57, PTP_min-t24P = .85, respectively). CV for tidal volume (V_T) and pressure support (PS) was lower in variable PSV group over time compared with NAVA group (P < .05).

CONCLUSIONS

In this randomized controlled trial including subjects with mild ARDS, NAVA and variable PSV had comparable effects on patient-ventilator synchronies and PTP. However, variable PSV reduced the variability of V_T and PS when compared with NAVA.

Lung and diaphragm protective ventilation: a synthesis of recent data

INTRODUCTION

: To adhere to the Hippocratic Oath, to "first, do no harm", we need to make every effort to minimize the adverse effects of mechanical ventilation. Our understanding of the mechanisms of ventilator-induced lung injury (VILI) and ventilator-induced diaphragm dysfunction (VIDD) has increased in recent years. Research focuses now on methods to monitor lung stress and inhomogeneity and targets we should aim for when setting the ventilator. In parallel, efforts to promote early assisted ventilation to prevent VIDD have revealed new challenges, such as titrating inspiratory effort and synchronizing the mechanical with the patients' spontaneous breaths, while at the same time adhering to lung-protective targets.

AREAS COVERED

This is a narrative review of the key mechanisms contributing to VILI and VIDD and the methods currently available to evaluate and mitigate the risk of lung and diaphragm injury.

EXPERT OPINION

Implementing lung and diaphragm protective ventilation requires individualizing the ventilator settings, and this can only be accomplished by exploiting in everyday clinical practice the tools available to monitor lung stress and inhomogeneity, inspiratory effort, and patient-ventilator interaction.

Neurally Adjusted Ventilatory Assist in Acute Respiratory Failure-A Narrative Review

Maintaining spontaneous breathing has both potentially beneficial and deleterious consequences in patients with acute respiratory failure, depending on the balance that can be obtained between the protecting and damaging effects on the lungs and the diaphragm. Neurally adjusted ventilatory assist (NAVA) is an assist mode, which supplies the respiratory system with a pressure proportional to the integral of the electrical activity of the diaphragm. This proportional mode of ventilation has the theoretical potential to deliver lung- and respiratory-muscle-protective ventilation by preserving the physiologic defense mechanisms against both lung overdistention and ventilator overassistance, as well as reducing the incidence of diaphragm disuse atrophy while maintaining patient–ventilator synchrony. This narrative review presents an overview of NAVA technology, its basic principles, the different methods to set the assist level and the findings of experimental and clinical studies which focused on lung and diaphragm protection, machine–patient interaction and preservation of breathing pattern variability. A summary of the findings of the available clinical trials which investigate the use of NAVA in acute respiratory failure will also be presented and discussed.

The physiological underpinnings of life-saving respiratory support

Treatment of respiratory failure has improved dramatically since the polio epidemic in the 1950s with the use of invasive techniques for respiratory support: mechanical ventilation and extracorporeal respiratory support. However, respiratory support is only a supportive therapy, designed to "buy time" while the disease causing respiratory failure abates. It ensures viable gas exchange and prevents cardiorespiratory collapse in the context of excessive loads. Because the use of invasive modalities of respiratory support is also associated with substantial harm, it remains the responsibility of the clinician to minimize such hazards. Direct iatrogenic consequences of mechanical ventilation include the risk to the lung (ventilator-induced lung injury) and the diaphragm (ventilator-induced diaphragm dysfunction and other forms of myotrauma). Adverse consequences on hemodynamics can also be significant. Indirect consequences (e.g., immobilization, sleep disruption) can have devastating long-term effects. Increasing awareness and understanding of these mechanisms of injury has led to a change in the philosophy of care with a shift from aiming to normalize gases toward minimizing harm. Lung (and more recently also diaphragm) protective ventilation strategies include the use of extracorporeal respiratory support when the risk of ventilation becomes excessive. This review provides an overview of the historical background of respiratory support, pathophysiology of respiratory failure and rationale for respiratory support, iatrogenic consequences from mechanical ventilation, specifics of the implementation of mechanical ventilation, and role of extracorporeal respiratory support. It highlights the need for appropriate monitoring to estimate risks and to individualize ventilation and sedation to provide safe respiratory support to each patient.

Circulating Skeletal Troponin During Weaning From Mechanical Ventilation and Their Association to Diaphragmatic Function: A Pilot Study

Background: Patients with acute respiratory failure (ARF) may need mechanical ventilation (MV), which can lead to diaphragmatic dysfunction and muscle wasting, thus making difficult the weaning from the ventilator. Currently, there are no biomarkers specific for respiratory muscle and their function can only be assessed trough ultrasound or other invasive methods. Previously, the fast and slow isoform of the skeletal troponin I (fsTnI and ssTnI, respectively) have shown to be specific markers of muscle damage in healthy volunteers. We aimed therefore at describing the trend of skeletal troponin in mixed population of ICU patients undergoing weaning from mechanical ventilation and compared the value of fsTnI and ssTnI with diaphragmatic ultrasound derived parameters.

Methods: In this prospective observational study we enrolled consecutive patients recovering from acute hypoxemic respiratory failure (AHRF) within 24 h from the start of weaning. Every day an arterial blood sample was collected to measure fsTnI, ssTnI, and global markers of muscle damage, such as ALT, AST, and CPK. Moreover, thickening fraction (TF) and diaphragmatic displacement (DE) were assessed by diaphragmatic ultrasound. The trend of fsTnI and ssTnI was evaluated during the first 3 days of weaning.

Results: We enrolled 62 consecutive patients in the study, with a mean age of 67 ± 13 years and 43 of them (69%) were male. We did not find significant variations in the ssTnI trend (p = 0.623), but fsTnI significantly decreased over time by 30% from Day 1 to Day 2 and by 20% from Day 2 to Day 3 (p < 0.05). There was a significant interaction effect between baseline ssTnI and DE [F₍₂₎ = 4.396, p = 0.015], with high basal levels of ssTnI being associated to a higher decrease in DE. On the contrary, the high basal levels of fsTnI at day 1 were characterized by significant higher DE at each time point.

Conclusions: Skeletal muscle proteins have a distinctive pattern of variation during weaning from mechanical ventilation. At day 1, a high basal value of ssTnI were associated to a higher decrease over time of diaphragmatic function while high values of fsTnI were associated to a higher displacement at each time point.

Comparison of advanced closed-loop ventilation modes with pressure support ventilation for weaning from mechanical ventilation in adults: A systematic review and meta-analysis

PURPOSE

To compare neurally adjusted ventilatory assist (NAVA), proportional assist ventilation (PAV), adaptive support ventilation (ASV) and Smartcare pressure support (Smartcare/PS) with standard pressure support ventilation (PSV) regarding their effectiveness for weaning critically ill adults from invasive mechanical ventilation (IMV).

METHODS

Electronic databases were searched to identify parallel-group randomized controlled trials (RCTs) comparing NAVA, PAV, ASV, or Smartcare/PS with PSV, in adult patients under IMV through July 28, 2021. Primary outcome was weaning success. Secondary outcomes included weaning time, total MV duration, reintubation or use of non-invasive MV (NIMV) within 48 h after extubation, in-hospital and intensive care unit (ICU) mortality, in-hospital and ICU length of stay (LOS) (PROSPERO registration No:CRD42021270299).

RESULTS

Twenty RCTs were finally included. Compared to PSV, NAVA was associated with significantly lower risk for in-hospital and ICU death and lower requirements for post-extubation NIMV. Moreover, PAV showed significant advantage over PSV in terms of weaning rates, MV duration and ICU LOS. No significant differences were found between ASV or Smart care/PS and PSV.

CONCLUSIONS

Moderate certainty evidence suggest that PAV increases weaning success rates, shortens MV duration and ICU LOS compared to PSV. It is also noteworthy that NAVA seems to improve in-hospital and ICU survival.

Neurally-Adjusted Ventilatory Assist (NAVA) versus Pneumatically Synchronized Ventilation Modes in Children Admitted to PICU

Traditionally, invasively ventilated children in the paediatric intensive care unit (PICU) are weaned using pneumatically-triggered ventilation modes with a fixed level of assist. The best weaning mode is currently not known. Neurally adjusted ventilatory assist (NAVA), a newer weaning mode, uses the electrical activity of the diaphragm (Edi) to synchronise ventilator support proportionally to the patient’s respiratory drive. We aimed to perform a systematic literature review to assess the effect of NAVA on clinical outcomes in invasively ventilated children with non-neonatal lung disease. Three studies (n = 285) were included for analysis. One randomised controlled trial (RCT) of all comers showed a significant reduction in PICU length of stay and sedative use. A cohort study of acute respiratory distress syndrome (ARDS) patients (n = 30) showed a significantly shorter duration of ventilation and improved sedation with the use of NAVA. A cohort study of children recovering from cardiac surgery (n = 75) showed significantly higher extubation success, shorter duration of ventilation and PICU length of stay, and a reduction in sedative use. Our systematic review presents weak evidence that NAVA may shorten the duration of ventilation and PICU length of stay, and reduce the requirement of sedatives. However, further RCTs are required to more fully assess the effect of NAVA on clinical outcomes and treatment costs in ventilated children.

Evolution of inspiratory muscle function in children during mechanical ventilation

BACKGROUND

There is no universally accepted method to assess the pressure-generating capacity of inspiratory muscles in children on mechanical ventilation (MV), and no study describing its evolution over time in this population.

METHODS

In this prospective observational study, we have assessed the function of the inspiratory muscles in children on various modes of MV. During brief airway occlusion maneuvers, we simultaneously recorded airway pressure depression at the endotracheal tube (ΔPaw, force generation) and electrical activity of the diaphragm (EAdi, central respiratory drive) over five consecutive inspiratory efforts. The neuro-mechanical efficiency ratio (NME, ΔPaw/EAdimax) was also computed. The evolution over time of these indices in a group of children in the pediatric intensive care unit (PICU) was primarily described. As a secondary objective, we compared these values to those measured in a group of children in the operating room (OR).

RESULTS

In the PICU group, although median NMEoccl decreased over time during MV (regression coefficient - 0.016, p = 0.03), maximum ΔPawmax remained unchanged (regression coefficient 0.109, p = 0.50). Median NMEoccl at the first measurement in the PICU group (after 21 h of MV) was significantly lower than at the only measurement in the OR group (1.8 cmH2O/µV, Q1-Q3 1.3-2.4 vs. 3.7 cmH2O/µV, Q1-Q3 3.5-4.2; p = 0.015). Maximum ΔPawmax in the PICU group was, however, not significantly different from the OR group (35.1 cmH2O, Q1-Q3 21-58 vs. 31.3 cmH2O, Q1-Q3 28.5-35.5; p = 0.982).

CONCLUSIONS

The function of inspiratory muscles can be monitored at the bedside of children on MV using brief airway occlusions. Inspiratory muscle efficiency was significantly lower in critically ill children than in children undergoing elective surgery, and it decreased over time during MV in critically ill children. This suggests that both critical illness and MV may have an impact on inspiratory muscle efficiency.

Comparative effects of neurally adjusted ventilatory assist and variable pressure support on lung and diaphragmatic function in a model of acute respiratory distress syndrome: A randomised animal study

BACKGROUND

Variable assisted mechanical ventilation has been shown to improve lung function and reduce lung injury. However, differences between extrinsic and intrinsic variability are unknown.

OBJECTIVE

To investigate the effects of neurally adjusted ventilatory assist (NAVA, intrinsic variability), variable pressure support ventilation (Noisy PSV, extrinsic variability) and conventional pressure-controlled ventilation (PCV) on lung and diaphragmatic function and damage in experimental acute respiratory distress syndrome (ARDS).

DESIGN

Randomised controlled animal study.

SETTING

University Hospital Research Facility.

SUBJECTS

A total of 24 juvenile female pigs.

INTERVENTIONS

ARDS was induced by repetitive lung lavage and injurious ventilation. Animals were randomly assigned to 24 h of either: 1) NAVA, 2) Noisy PSV or 3) PCV (n=8 per group). Mechanical ventilation settings followed the ARDS Network recommendations.

MEASUREMENTS

The primary outcome was histological lung damage. Secondary outcomes were respiratory variables and patterns, subject-ventilator asynchrony (SVA), pulmonary and diaphragmatic biomarkers, as well as diaphragmatic muscle atrophy and myosin isotypes.

RESULTS

Global alveolar damage did not differ between groups, but NAVA resulted in less interstitial oedema in dorsal lung regions than Noisy PSV. Gas exchange and SVA incidence did not differ between groups. Compared with Noisy PSV, NAVA generated higher coefficients of variation of tidal volume and respiratory rate. During NAVA, only 40.4% of breaths were triggered by the electrical diaphragm signal. The IL-8 concentration in lung tissue was lower after NAVA compared with PCV and Noisy PSV, whereas Noisy PSV yielded lower type III procollagen mRNA expression than NAVA and PCV. Diaphragmatic muscle fibre diameters were smaller after PCV compared with assisted modes, whereas expression of myosin isotypes did not differ between groups.

CONCLUSION

Noisy PSV and NAVA did not reduce global lung injury compared with PCV but affected different biomarkers and attenuated diaphragmatic atrophy. NAVA increased the respiratory variability; however, NAVA yielded a similar SVA incidence as Noisy PSV.

TRIAL REGISTRATION

This trial was registered and approved by the Landesdirektion Dresden, Germany (AZ 24-9168.11-1/2012-2).

Ventilator Liberation in the Pediatric ICU

Despite the accepted importance of minimizing time on mechanical ventilation, only limited guidance on weaning and extubation is available from the pediatric literature. A significant proportion of patients being evaluated for weaning are actually ready for extubation, suggesting that weaning is often not considered early enough in the course of ventilation. Indications for extubation are often not clear, although a trial of spontaneous breathing on CPAP without pressure support seems an appropriate prerequisite in many cases. Several indexes have been developed to predict weaning and extubation success, but the available literature suggests they offer little or no improvement over clinical judgment. New techniques for assessing readiness for weaning and predicting extubation success are being developed but are far from general acceptance in pediatric practice. While there have been some excellent physiologic, observational, and even randomized controlled trials on aspects of pediatric ventilator liberation, robust research data are lacking. Given the lack of data in many areas, a determined approach that combines systematic review with consensus opinion of international experts could generate high-quality recommendations and terminology definitions to guide clinical practice and highlight important areas for future research in weaning, extubation readiness, and liberation from mechanical ventilation following pediatric respiratory failure.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

Factors affecting the use of neurally adjusted ventilatory assist in the adult critical care unit: a clinician survey

Background

Neurally adjusted ventilatory assist (NAVA) involves an intricate interaction between patient, clinician and technology. To improve our understanding of this complex intervention and to inform future trials, this survey aimed to examine clinician attitudes, beliefs and barriers to NAVA use in critically ill adults within an institution with significant NAVA experience.

Methods

A survey of nurses, doctors and physiotherapists in four Intensive Care Units (ICUs) of one UK university-affiliated hospital (75 NAVA equipped beds). The survey consisted of 39 mixed open and structured questions. The hospital had 8 years of NAVA experience prior to the survey.

Results

Of 466 distributed questionnaires, 301 (64.6%) were returned from 236 nurses (78.4%), 53 doctors (17.6%) and 12 physiotherapists (4.0%). Overall, 207/294 (70.4%) reported clinical experience. Most agreed that NAVA was safe (136/177, 76.8%) and clinically effective (99/176, 56.3%) and most perceived ‘improved synchrony’, ‘improved comfort’ and ‘monitoring the diaphragm’ to be key advantages of NAVA. ‘Technical issues’ (129/189, 68.3%) and ‘NAVA signal problems’ (94/180, 52.2%) were the most cited clinical disadvantage and cause of mode cross-over to Pressure Support Ventilation (PSV), respectively. Most perceived NAVA to be more difficult to use than PSV (105/174, 60.3%), although results were mixed when compared across different tasks. More participants preferred PSV to NAVA for initiating ventilator weaning (93/171 (54.4%) vs 29/171 (17.0%)). A key barrier to use and a consistent theme throughout was ‘low confidence’ in relation to NAVA use.

Conclusions

In addition to broad clinician support for NAVA, this survey describes technical concerns, low confidence and a perception of difficulty above that associated with PSV. In this context, high-quality training and usage algorithms are critically important to the design and of future trials, to clinician acceptance and to the clinical implementation and future success of NAVA.

Techniques to monitor respiratory drive and inspiratory effort

PURPOSE OF REVIEW

There is increased awareness that derangements of respiratory drive and inspiratory effort are frequent and can result in lung and diaphragm injury together with dyspnea and sleep disturbances. This review aims to describe available techniques to monitor drive and effort.

RECENT FINDINGS

Measuring drive and effort is necessary to quantify risk and implement strategies to minimize lung and the diaphragm injury by modifying sedation and ventilation. Evidence on the efficacy of such strategies is yet to be elucidated, but physiological and epidemiological data support the need to avoid injurious patterns of breathing effort.Some techniques have been used in research for decades (e.g., esophageal pressure or airway occlusion pressure), evidence on their practical utility is growing, and technical advances have eased implementation. More novel techniques (e.g., electrical activity of the diaphragm and ultrasound) are being investigated providing new insights on their use and interpretation.

SUMMARY

Available techniques provide reliable measures of the intensity and timing of drive and effort. Simple, noninvasive techniques might be implemented in most patients and the more invasive or time-consuming in more complex patients at higher risk. We encourage clinicians to become familiar with technical details and physiological rationale of each for optimal implementation.

NAVA and PAV+ for lung and diaphragm protection

PURPOSE OF REVIEW

Complications of mechanical ventilation, such as ventilator-induced lung injury (VILI) and ventilator-induced diaphragmatic dysfunction (VIDD), adversely affect the outcome of critically ill patients. Although mostly studied during control ventilation, it is increasingly appreciated that VILI and VIDD also occur during assisted ventilation. Hence, current research focuses on identifying ways to monitor and deliver protective ventilation in assisted modes. This review describes the operating principles of proportional modes of assist, their implications for lung and diaphragm protective ventilation, and the supporting clinical data.

RECENT FINDINGS

Proportional modes of assist, proportional assist ventilation, PAV, and neurally adjusted ventilatory assist, NAVA, deliver a pressure assist that is proportional to the patient's effort, enabling ventilation to be better controlled by the patient's brain. This control underlies the potential of proportional modes to avoid over-assist and under-assist, improve patient--ventilator interaction, and provide protective ventilation. Indeed, in clinical studies, proportional modes have been associated with reduced asynchronies, enhanced diaphragmatic recovery, and limitation of excessive tidal volume. Additionally, proportional modes facilitate better monitoring of the delivery of protective assisted ventilation.

SUMMARY

Physiological rationale and clinical data suggest a potential role for proportional modes of assist in providing and monitoring lung and diaphragm protective ventilation.

Diaphragm protection: what should we target?

PURPOSE OF REVIEW

Diaphragm weakness can impact survival and increases comorbidities in ventilated patients. Mechanical ventilation is linked to diaphragm dysfunction through several mechanisms of injury, referred to as myotrauma. By monitoring diaphragm activity and titrating ventilator settings, the critical care clinician can have a direct impact on diaphragm injury.

RECENT FINDINGS

Both the absence of diaphragm activity and excessive inspiratory effort can result in diaphragm muscle weakness, and recent evidence demonstrates that a moderate level of diaphragm activity during mechanical ventilation improves ICU outcome. This supports the hypothesis that by avoiding ventilator overassistance and underassistance, the clinician can implement a diaphragm-protective ventilation strategy. Furthermore, eccentric diaphragm contractions and end-expiratory shortening could impact diaphragm strength as well. This review describes these potential targets for diaphragm protective ventilation.

SUMMARY

A ventilator strategy that results in appropriate levels of diaphragm activity has the potential to be diaphragm-protective and improve clinical outcome. Monitoring respiratory effort during mechanical ventilation is becoming increasingly important.

The role of computer-based clinical decision support systems to deliver protective mechanical ventilation

PURPOSE OF REVIEW

Mechanical ventilation of adults and children with acute respiratory failure necessitates balancing lung and diaphragm protective ventilation. Computerized decision support (CDS) offers advantages in circumstances where complex decisions need to be made to weigh potentially competing risks, depending on the physiologic state of the patient.

RECENT FINDINGS

Significant variability in how ventilator protocols are applied still exists and clinical data show that there continues to be wide variability in ventilator management. We have developed a CDS, which we are currently testing in a Phase II randomized controlled trial. The CDS is called Real-time Effort Driven ventilator management (REDvent). We will describe the rationale and methods for development of CDS for lung and diaphragm protective ventilation, using the REDvent CDS as an exemplar.

SUMMARY

Goals for achieving compliance and physiologic objectives can be met when CDS instructions are simple and explicit, provide the clinician with the underlying rule set, permit acceptable reasons for declining and allow for iterative adjustments.

Continuous assessment of neuro-ventilatory drive during 12 h of pressure support ventilation in critically ill patients

Introduction

Pressure support ventilation (PSV) should allow spontaneous breathing with a “normal” neuro-ventilatory drive. Low neuro-ventilatory drive puts the patient at risk of diaphragmatic atrophy while high neuro-ventilatory drive may causes dyspnea and patient self-inflicted lung injury. We continuously assessed for 12 h the electrical activity of the diaphragm (EAdi), a close surrogate of neuro-ventilatory drive, during PSV. Our aim was to document the EAdi trend and the occurrence of periods of “Low” and/or “High” neuro-ventilatory drive during clinical application of PSV.

Method

In 16 critically ill patients ventilated in the PSV mode for clinical reasons, inspiratory peak EAdi peak (EAdi_PEAK), pressure time product of the trans-diaphragmatic pressure per breath and per minute (PTP_DI/b and PTP_DI/min, respectively), breathing pattern and major asynchronies were continuously monitored for 12 h (from 8 a.m. to 8 p.m.). We identified breaths with “Normal” (EAdi_PEAK 5–15 μV), “Low” (EAdi_PEAK < 5 μV) and “High” (EAdi_PEAK > 15 μV) neuro-ventilatory drive.

Results

Within all the analyzed breaths (177.117), the neuro-ventilatory drive, as expressed by the EAdi_PEAK, was “Low” in 50.116 breath (28%), “Normal” in 88.419 breaths (50%) and “High” in 38.582 breaths (22%). The average times spent in “Low”, “Normal” and “High” class were 1.37, 3.67 and 0.55 h, respectively (p < 0.0001), with wide variations among patients. Eleven patients remained in the “Low” neuro-ventilatory drive class for more than 1 h, median 6.1 [3.9–8.5] h and 6 in the “High” neuro-ventilatory drive class, median 3.4 [2.2–7.8] h. The asynchrony index was significantly higher in the “Low” neuro-ventilatory class, mainly because of a higher number of missed efforts.

Conclusions

We observed wide variations in EAdi amplitude and unevenly distributed “Low” and “High” neuro ventilatory drive periods during 12 h of PSV in critically ill patients. Further studies are needed to assess the possible clinical implications of our physiological findings.

Lung- and Diaphragm-Protective Ventilation

Mechanical ventilation can cause acute diaphragm atrophy and injury, and this is associated with poor clinical outcomes. Although the importance and impact of lung-protective ventilation is widely appreciated and well established, the concept of diaphragm-protective ventilation has recently emerged as a potential complementary therapeutic strategy. This Perspective, developed from discussions at a meeting of international experts convened by PLUG (the Pleural Pressure Working Group) of the European Society of Intensive Care Medicine, outlines a conceptual framework for an integrated lung- and diaphragm-protective approach to mechanical ventilation on the basis of growing evidence about mechanisms of injury. We propose targets for diaphragm protection based on respiratory effort and patient-ventilator synchrony. The potential for conflict between diaphragm protection and lung protection under certain conditions is discussed; we emphasize that when conflicts arise, lung protection must be prioritized over diaphragm protection. Monitoring respiratory effort is essential to concomitantly protect both the diaphragm and the lung during mechanical ventilation. To implement lung- and diaphragm-protective ventilation, new approaches to monitoring, to setting the ventilator, and to titrating sedation will be required. Adjunctive interventions, including extracorporeal life support techniques, phrenic nerve stimulation, and clinical decision-support systems, may also play an important role in selected patients in the future. Evaluating the clinical impact of this new paradigm will be challenging, owing to the complexity of the intervention. The concept of lung- and diaphragm-protective ventilation presents a new opportunity to potentially improve clinical outcomes for critically ill patients.

Real-Time Effort Driven Ventilator Management: A Pilot Study

OBJECTIVES

Mechanical ventilation of patients with acute respiratory distress syndrome should balance lung and diaphragm protective principles, which may be difficult to achieve in routine clinical practice. Through a Phase I clinical trial, we sought to determine whether a computerized decision support-based protocol (real-time effort-driven ventilator management) is feasible to implement, results in improved acceptance for lung and diaphragm protective ventilation, and improves clinical outcomes over historical controls.

DESIGN

Interventional nonblinded pilot study.

SETTING

PICU.

PATIENTS

Mechanically ventilated children with acute respiratory distress syndrome.

INTERVENTIONS

A computerized decision support tool was tested which prioritized lung-protective management of peak inspiratory pressure-positive end-expiratory pressure, positive end-expiratory pressure/FIO2, and ventilatory rate. Esophageal manometry was used to maintain patient effort in a physiologic range. Protocol acceptance was reported, and enrolled patients were matched 4:1 with respect to age, initial oxygenation index, and percentage of immune compromise to historical control patients for outcome analysis.

MEASUREMENTS AND MAIN RESULTS

Thirty-two patients were included. Acceptance of protocol recommendations was over 75%. One-hundred twenty-eight matched historical controls were used for analysis. Compared with historical controls, patients treated with real-time effort-driven ventilator management received lower peak inspiratory pressure-positive end-expiratory pressure and tidal volume, and higher positive end-expiratory pressure when FIO2 was greater than 0.60. Real-time effort-driven ventilator management was associated with 6 more ventilator-free days, shorter duration until the first spontaneous breathing trial and 3 fewer days on mechanical ventilation among survivors (all p ≤ 0.05) in comparison with historical controls, while maintaining no difference in the rate of reintubation.

CONCLUSIONS

A computerized decision support-based protocol prioritizing lung-protective ventilation balanced with reduction of controlled ventilation to maintain physiologic levels of patient effort can be implemented and may be associated with shorter duration of ventilation.