Pressure Support Research Articles

Abstract 4135318: Comparison of Right Ventricular Function Changes Between Volume Control and Pressure Support Ventilation Modes: A Prospective Study Using S' Prime Values

Background: This study assesses changes in right ventricular function by measuring S' values during the transition from volume control-assist control (VC-AC) to pressure support ventilation (PSV). Transitioning from VC-AC to PSV reduces the mean airway pressure (P mean) which causes a decrease in right ventricular afterload and also potentially improves venous return and right ventricular preload. PSV allows spontaneous breathing efforts, possibly increasing cardiac output. Thus, we expect a consistent increase in S' value when changing ventilator modes. Methods: This prospective observational study included ICU patients on invasive mechanical ventilation for over 24 hours. The clinical team decided when to switch from VC-AC to PSV. An average of three S' measurements was taken during VC-AC and within 10 minutes of transitioning to PSV. Sedation, vasopressor use, and Richmond Agitation-Sedation Scale scores were consistent throughout the measurements. The study was approved by the Albert Einstein College of Medicine IRB (#2023-15068) Results: Seventeen patients were included in the study, with an average age of 61.29 years (SD 11.39). Of these, 6 (35.3%) were female. The mean S' during VC-AC was 12.79 ± 4.52, and upon transitioning to PSV, it was 14.56 ± 3.89 (p-value 0.47). The intra-observer variability for S' was 5.3%. Of the seventeen patients, 5/17 (29%) showed an S' change of less than 5.3% and were deemed to have no significant variation; 7/17 (41%) experienced a significant decrease in S' (15.41% ± 7.29% SD), while the remaining 5/17 (29%) showed a significant increase (19.31 ± 13.23%). Conclusion: Our study demonstrates that transitioning from VC-AC to PSV results in variable changes in right ventricular systolic function, as indicated by S' values. Contrary to our expectations of a consistent increase, the interplay between S' values and ventilator mode changes appears to be non-linear, suggesting other factors may influence cardiopulmonary interactions in spontaneously breathing ventilated patients. These findings highlight the complexity of these interactions, underscoring the need for individualized patient management and paving the way for further research with a larger cohort.

Personalized positive end-expiratory pressure in spontaneously breathing patients with acute respiratory distress syndrome by simultaneous electrical impedance tomography and transpulmonary pressure monitoring: a randomized crossover trial.

Personalized positive end-expiratory pressure (PEEP) might foster lung and diaphragm protection in patients with acute respiratory distress syndrome (ARDS) who are undergoing pressure support ventilation (PSV). We aimed to compare the physiologic effects of personalized PEEP set according to synchronized electrical impedance tomography (EIT) and driving transpulmonary pressure (∆PL) monitoring against a classical lower PEEP/FiO2 table in intubated ARDS patients undergoing PSV. A cross-over randomized multicenter study was conducted in 30 ARDS patients with simultaneous recording of the airway, esophageal and transpulmonary pressure, together with EIT during PSV. Following a decremental PEEP trial (18 cmH2O to 4 cmH2O), PEEPEIT-∆PL was identified as the level with the smallest difference between lung overdistension and collapse. A low PEEP/FiO2 table was used to select PEEPTABLE. Each PEEP strategy was applied for 20min, and physiologic data were collected at the end of each step. The PEEP trial was well tolerated. Median PEEPEIT-∆PL was higher than PEEPTABLE (10 [8-12] vs. 8 [5-10] cmH2O; P = 0.021) and, at the individual patient level, PEEPEIT-∆PL level differed from PEEPTABLE in all patients. Overall, PEEPEIT-∆PL was associated with lower dynamic ∆PL (P < 0.001) and pressure-time product (P < 0.001), but there was variability among patients. PEEPEIT-∆PL also decreased respiratory drive and effort (P < 0.001), improved regional lung mechanics (P < 0.05) and reversed lung collapse (P = 0.007) without increasing overdistension (P = 0.695). Personalized PEEP selected using synchronized EIT and transpulmonary pressure monitoring could be associated with reduced dynamic lung stress and metabolic work of breathing in ARDS patients undergoing PSV.

Evaluation of decision support to wean patients from mechanical ventilation in intensive care: a prospective study reporting clinical and physiological outcomes.

This study investigated the clinical and physiological response to use of the BEACON Caresystem, a bedside open-loop decision support system providing advice to guide clinicians when weaning patients from invasive mechanical ventilation. Multicenter prospective study conducted in five adult intensive care units in the UK. Following screening and assent, intubated patients mechanically ventilated for > 24 h were randomized to intervention or usual care. Intervention consisted of application of the BEACON Caresystem's advice on tidal volume/inspiratory pressure, inspired oxygen, respiratory rate and PEEP. Usual care was defined as local clinical practice. The primary outcome was duration of mechanical ventilation. Secondary outcomes quantified prolonged intubation and survival; adverse events; ventilator settings and physiological state; time spent in ventilator modes; links to other therapy; the frequency of advice utilization and time spent outside normal physiological limits. The study was terminated early with a total of 112 patients included. Fifty-four were randomised to the intervention arm and fifty-eight to usual care. The study was underpowered and no significant differences were seen in duration of mechanical ventilation (p = 0.773), prolonged intubation or survival. Intervention arm patients had lower rates of adverse events (p = 0.016), including fewer hypoxaemic events (p = 0.008) and lower values of PEEP (p = 0.030) and tidal volume (p = 0.042). Values of peak inspiratory pressure and pressure support were reduced but at the boarder of statistical significance (p = 0.104, p = 0.093, respectively). No differences were seen for time in ventilator mode or other therapy. Advice presented by the decision support system was applied at the beside an average of 88% of occasions, with a significantly increased number of changes only in inspired oxygen fraction. No significant differences were seen in time spent outside physiological limits. This study investigated the use of the BEACON Caresystem, an open loop clinical decision support system providing advice on ventilator settings. It was terminated early, with no significant difference shown in duration of mechanical ventilation, the primary outcome. Application of advice indicated potential for fewer adverse events and improved physiological status. (Trial registration ClinicalTrials.gov under NCT03249623. Registered 22nd June 2017).

A cluster randomized trial on inspiratory effort-targeted pressure support adjustment strategy in patients undergoing assisted mechanical ventilation: protocol for the IT-PSV study

BackgroundPressure support ventilation (PSV) is one of the most frequently used ventilator modes in the intensive care unit (ICU). The successful implementation of PSV depends on matching the patient’s inspiratory effort with the ventilator support. In clinical practice, the pressure support level is usually set and adjusted according to tidal volume and respiratory rate. However, these parameters may not fully represent the patient’s effort. Previous studies have shown that pressure muscle index (PMI), which is measured as the difference between the peak and plateau airway pressure during an end-inspiratory airway occlusion, could reliably determine the low and high inspiratory effort during PSV. Herein we present the study protocol for the Inspiratory effort-Targeted Pressure Support Ventilation (IT-PSV) trial to determine the effect of a PMI-targeted pressure support setting strategy on clinical outcomes in patients undergoing PSV.Methods and analysisThis is a cluster randomized controlled trial. Sixteen ICUs in academic hospitals will be included, eight of which will be randomly allocated to the PMI-targeted group and eight to the tidal volume/respiratory rate-targeted group. Before the initiation of the study, a four-week comprehensive training program, which includes courses of PSV initiation, pressure support adjustment, and weaning process, will be conducted for all staff in the participating ICUs. Adult patients with acute hypoxic respiratory failure and undergoing PSV within 24 h will be included. Pressure support setting and adjustment will follow the strategy according to the grouping. The primary outcome is the ventilator-free days at 28 days after enrollment. The patients will be followed up until successful weaning or separation of mechanical ventilation, death, hospital discharge, or until 28 days after randomization, whichever comes first.DiscussionThe IT-PSV trial will examine the effect of an inspiratory effort-targeted PSV setting strategy on the duration of mechanical ventilation. If positive, it will provide a new physiological-based PSV management that could potentially facilitate protective assisted ventilation.Clinical trial registrationClinicalTrials.gov, identifier NCT06526598.

Manifestations of toxic pulmonary edema during respiratory support in an experiment

BACKGROUND: Currently, respiratory support is successfully used to treat pulmonary edema of non-toxic origin. The manifestations of pulmonary edema of non-toxic origin and toxic pulmonary edema have similar features, so respiratory support can be effective in treating the latter. AIM: To describe the manifestations of toxic pulmonary edema in rabbits and demonstrate the effectiveness of artificial pulmonary ventilation with support of positive end-expiratory pressure (PEEP) in case of severe intoxication with thermal destruction products of fluoroplastic-4. MATERIALS AND METHODS: Three rabbits were used in the study: rabbit N 1 (control), rabbit N 2 (intoxication) and rabbit N 3 (treatment). Rabbits N 2 and 3 were subjected to severe intoxication with thermal destruction products of fluoroplastic-4 (1,5 HLC50, 15 min). For treatment, rabbit N 3 (treatment), an hour after exposure, underwent mechanical ventilation with PEEP (pressure-controlled mode; oxygen fraction — 0,3; starting PEEP — 5 cm H2O, tidal volume — 20–25 ml). At various times, chest radiography was performed, oxygenation index, hemoglobin saturation (SaO2), and partial pressure of carbon dioxide in exhaled air (PetCO2) were determined. Posthumously, pathological changes in lung tissue, pulmonary coefficient were determined, and histological examination was performed. RESULTS: Exposure of rabbit N 2 (intoxication) to the thermal destruction products of fluoroplastic-4 led to the sequential formation of the interstitial and alveolar phases of toxic pulmonary edema, which contributed to its death 13 hours after exposure. As SaO2 decreased and PetCO2 increased (3 and 5 hours after exposure), in rabbit N 3 (treatment), during respiratory support, PEEP was increased twice by 2 cm H2O (maintaining a given respiratory volume), which led to the normalization of the studied parameters. On the 7th day after exposure, the condition of rabbit N 3 (treatment) did not differ from the condition of rabbit N 1 (control); no pathological changes in the respiratory system were detected. CONCLUSION: Carrying out mechanical ventilation with PEEP, started an hour after exposure (with a stepwise increase in PEEP as the condition worsens), is effective for correcting toxic pulmonary edema in rabbits caused by severe intoxication with the thermal destruction products of fluoroplastic-4.

Feasibility of a custom-tailored, evidence-based, theory-informed, intervention to prevent burnout and reduce stress for healthcare professionals: protocol for a single-arm trial

BackgroundHealthcare professionals face high levels of occupational stress, time pressure, workload, and poor organizational support. This makes them particularly vulnerable to burnout. The COVID-19 pandemic has further exacerbated this situation. This single-arm, multicenter, mixed-methods feasibility study pilots the LAGOM program: A tailored, evidence-based intervention to prevent burnout and reduce stress among healthcare professionals.MethodsParticipants will include healthcare professionals (N = 30) working at Charité–Universitätsmedizin Berlin and Immanuel Hospital, Berlin. LAGOM focuses on support for individual behavior change and personal resources and also addresses the organizational level. The intervention´s feasibility will be evaluated through a non-randomized feasibility trial with a mixed methods process evaluation. The exploratory primary study aims are to assess the acceptability and feasibility of the (1) evaluation procedures and of the (2) intervention content and structure using study records, standardized questionnaires, protocol checklists, and diaries. Exploratory effectiveness analysis will take place as well. Further, semi-structured interviews (n = 3 to 6) and electrophysiological measurements (n = 20) will be conducted.DiscussionCustom-tailored, well-implemented multi-level interventions are needed to prevent burnout and reduce stress among healthcare professionals. Long-term strategies are warranted to sustainably implement effective programs. This feasibility study helps to refine trial procedures and content of the LAGOM program for a randomized controlled trial to evaluate the intervention’s effectiveness.Trial registrationGerman Clinical Trials Register: DRKS00032014, registered 17th October 2023.

Short (30 Minutes) versus long (120 Minutes) spontaneous breathing trial among patients with difficult weaning (SL-SBT Trial)

BackgroundThe optimal duration of spontaneous breath trial (SBT) for patients with difficult extubation from mechanical ventilation is unknown. ObjectiveThis study compared extubation success with two different durations of SBT in patients who failed their first SBT. MethodsThis single-center randomized controlled trial included adults on mechanical ventilation who had failed their first SBT. The participants were randomized to receive pressure support ventilation (PSV) for either 30 or 120 min. Our primary outcome was the rate of successful extubation (without reintubation within 48 h). Key secondary outcomes were the length of intensive care unit (ICU) and hospital stay and in-hospital and 90-day mortality. ResultsA total of 119 patients (62.2 % male) with a mean age of 53.9 years were randomized to undergo SBT for either 30 min (n = 60) or 120 min (n = 59). Among them, 82.4 % of patients had hypercapnic respiratory failure. The rates of successful extubation were similar with SBT of 30 min and 120 min (58.3 % vs. 59.3 %, respectively; p = 0.91). There were no significant differences between the two groups in terms of the durations of ICU and hospital stay or in-hospital and 90-day mortality. ConclusionsExtubation success and other clinically important outcomes were comparable between short (30 min) and long (120 min) SBT in difficult weaning. A 30-minute SBT may be acceptable in this setting.

Pressure control and support technology for spacecraft space exploration

Abstract As a top-level requirement for ensuring the exploration work inside and outside the spacecraft, the cabin pressure control technology of the spacecraft ensures the safety of astronauts and is one of the core systems for maintaining astronaut space exploration. This article introduces the pressure control and support technology for space environment exploration and constructs a cabin pressure control model. Through simulation verification, the constructed model meets the requirements of spacecraft cabin pressure control, and can effectively save the extravehicular activity air source. This technology can provide a reference for pressure support systems for manned space stations, Mars, and lunar exploration spacecraft.

Comparing pressure support ventilation to spontaneous breathing trial during ventilator weaning after surgery: impact on postoperative atelectasis

Comparing pressure support ventilation to spontaneous breathing trial during ventilator weaning after surgery: impact on postoperative atelectasis

Forecasting Constraints from Surface Brightness Fluctuations in Galaxy Clusters

Studies of surface brightness (SB) fluctuations in the intracluster medium present an indirect estimate of turbulent pressure support and associated Mach numbers. While high-resolution X-ray spectroscopy can directly constrain line-of-sight gas motions, including those due to turbulence, such observations are relatively expensive and will be limited to nearby, bright clusters. In this respect, SB fluctuations are the most economical means to constrain turbulent motions at large cluster radii across a range of redshifts and masses. To forecast what current and future X-ray and Sunyaev–Zel’dovich facilities may achieve in SB fluctuation studies, I review and synthesize matters of accuracy and precision with respect to calculating power spectra of SB fluctuations, from which turbulent properties are derived. Balancing concerns of power spectrum accuracy and precision across a range of spatial scales, I propose the use of three annuli with [0, 0.4]R 500, [0.4, 1]R 500, and [1, 1.5]R 500. Adopting these three regions, I calculate the uncertainty in the hydrostatic mass bias, σbM , that can be achieved for various instruments in several scenarios. I find that Lynx and AtLAST are competitive in their constraints at R 500, while AtLAST should perform better when constraining σbM at R 200.

Successful management of complete heart block in checkpoint inhibitor induced myocarditis by left bundle branch area pacing: a case report

Abstract Background Optimal management of checkpoint inhibitor-induced complete heart block is unknown. Previous reports showed relatively high incidence of pacing failure due to the co-existing myocarditis. Case summary A 71-year-old male with a prior history of stage IV metastatic squamous cell lung cancer presents was admitted for dyspnoea and hypotension 10 days after checkpoint inhibitor treatment using pembrolizumab. He was found to have myocarditis, third-degree AV block, severe left ventricular systolic dysfunction with EF 35%, and required pressure support. A dual chamber pacemaker using left bundle branch area pacing (LBBAP) was urgently placed that immediately improved his haemodynamics. Both the cathode and anode were able to capture the ventricle at different pacing outputs. The patient was taken off all intravenous pressors and successfully transferred to a larger centre for further management of the myocarditis with no further arrhythmia or hypotension. Discussion In conclusion, because of the unique ability to capture a large amount of myocardium from both the tip and ring electrodes as well as the ability to deliver cardiac resynchronization therapy, LBBAP may be the preferred pacing strategy in patients who develop complete heart block due to checkpoint inhibitor-induced myocarditis.

Noninvasive Positive Pressure Ventilation versus High-Flow Nasal Cannula for Chronic Obstructive Pulmonary Disease: An Updated Narrative Review.

Chronic obstructive pulmonary disease (COPD) is one of the most common clinical respiratory illnesses, defined by permanent pathological deterioration that leads to respiratory failure. Regarding COPD treatment, oxygen therapy is very important. Non-invasive positive pressure ventilation (NPPV) is a technique for non-invasive mechanical ventilation that enables patients to get positive pressure support without the need of an artificial airway. Instead, it merely employs the mask by covering the mouth and nose, or simply the nose of patients. NPPV has been shown to be beneficial for COPD patients experiencing respiratory failure. High-flow nasal cannula (HFNC) oxygen therapy shows some advantages, including the reduction of anatomical dead space, the prompt correction of low oxygen levels as well as the improvement of patients' tolerance. Owing to its continuous progress, ventilation technology strongly improves COPD treatment. In this study, the authors analyze the application of NPPV and HFNC in COPD so as to provide recommendations for mechanical ventilation treatment.

Association of soluble ST2 with heart failure and other comorbidities in patients with severe coronary heart disease

Abstract Background Circulating levels of soluble suppression of tumorigenicity-2 (sST2) reflect vascular congestion, inflammation, and fibrosis. sST2 has been proposed as a useful biomarker to predict the mortality and hospitalization due to heart failure. However, there is limited evidence regarding the relationship between sST2 and heart failure, as well as other comorbidities, in severe coronary heart disease (CAD). Purpose This study aims to measure the circulating levels of soluble ST2 (sST2) in a large population of patients with severe CAD to determine its association with heart failure, cardiac function, inflammation, and other important comorbidities. Methods This subanalysis is part of the ongoing perspective observational study. Available serum samples from 520 patients undergoing elective coronary artery bypass grafting (CABG) were analysed for sST2 levels. The inclusion criteria were written informed consent and age between 18-85 years. Exclusion criteria for this analysis were severe valvular disease, severe chronic obstructive pulmonary disease, oxygen therapy, nocturnal positive airway pressure support or mechanical ventilation, and the need for catecholamines or circulatory assist devices. The circulating levels of human sST2 were measured from frozen serum (-80°C) using commercially available ELISA kits. The plasma was diluted 100 times to detect sST2 levels (assay range of 31.2 - 2,000 pg/mL). Two measurements were taken to account as means for intra-assay variabilities. Logarithmic transformation was used to convert non-normal distributed data. Student t' test and linear regression were applied to categorical or continuous variables as appropriate. Results sST2 levels (median 20.4 ng/ml, [IQR 15.5 – 28.8]) significantly predict worse left ventricular ejection fraction (β = -0.164, p = 0.006), and significantly correlate with levels of NT-proBNP (β = 3.263, p &amp;lt; 0.001), hs-Troponin T (β = 3.391, p &amp;lt; 0.001), high-sensitivity C-reactive protein (β = 2.472, p = 0.014) and heart failure (p= 0.002). Interestingly, common comorbidities such as chronic kidney disease (estimated glomerular filtration rate &amp;lt; 60 mL/min/1.73 m2, p = 0.004), diabetes mellitus (p = 0.001) and higher levels of glycated haemoglobin (HbA1c, β = 3.615, p &amp;lt; 0.001) showed also a significant association with sST2 levels. No significant association of sST2 was observed with arterial hypertension (p = 0.190), atrial fibrillation (p = 0.289), obesity (BMI ≥ 30 kg/m2, p = 0.302), sleep apnoea (apnoea-hypopnoea index ≥ 15/h, p = 0.068), peripheral artery disease (p = 0.823), or previous stroke (p = 0.861). Conclusion(s) Circulating levels of sST2 significantly correlate with heart failure, NT-proBNP, hs-TnT, and hs-CRP in patients with severe CAD. Additionally, sST2 levels were found to be elevated in patients with diabetes mellitus and chronic kidney disease.

THE RUSSIAN-UKRAINIAN WAR AND THE INTERNATIONAL COMMUNITY: MAIN DIRECTIONS, PROBLEMS AND SOME LESSONS OF WESTERN SUPPORT FOR UKRAINE

Despite the heroic resistance of Ukrainians, in particular the Armed Forces of Ukraine, during the current Russian-Ukrainian war, without effective assistance, especially military, from the Western democratic world, Ukraine would hardly have withstood the Russian aggressor's more than two-year-long large-scale armed invasion and would have been able to preserve national statehood and the Ukrainian nation from genocide and destruction in the event of a protracted war of attrition. For such a war, Ukraine will need at least $150 billion a year, which can only be provided by its Western partners. And the World Bank estimates that over the next 10 years, about $500 billion will be needed to rebuild Ukraine's war-torn infrastructure, which is more than Ukraine's GDP, so without investment and financial assistance from our partners, we will not be able to find these resources in the country either. The purpose of the article is to systematise the huge amount of information available in accessible/open sources about the central, fateful event of modern international relations - Russia's war against Ukraine and the international community's attitude to it, in particular, to highlight the main directions, problems and some preliminary lessons of Western support for Ukraine in its resistance to Russian aggression, which can already be outlined in the third year of the large-scale war. Russia's unprovoked and brutal large-scale armed attack on Ukraine in February 2022 left no choice but to recognise this aggression as an attack on European and Euro-Atlantic democratic values and the fundamental principles on which the United Nations is built. This was a manifestation of the next stage of Russia's global hybrid war against the West. Unprecedented international support for Ukraine and powerful pressure on the aggressor country - Russia - is manifested in active political, financial, military, and humanitarian assistance to Ukraine from EU and NATO member states and other countries. In total, more than 50 countries provide such assistance to Ukraine during the war. However, our Western partners do not yet have a common strategic plan for the Russian-Ukrainian war and its victorious conclusion, and in the third year of the war, they are increasingly talking about different options for peace talks with the aggressor, so Ukraine must develop its own grand strategy, which should be based on the fact that war and peace coexist and that Russia poses a long-term threat to it and the entire democratic world.

Best Evidence Summary for the Prevention of Pressure Injuries in Orthopaedic Patients.

To systematically search, evaluate and synthesise the most robust evidence regarding pressure injury prevention in orthopaedic patients admitted to general wards. The present study provides an evidence-based summary of the most robust findings, adhering to the evidence guidelines established by the Center for Evidence-Based Nursing of Fudan University. According to the "6S" model, a systematic search was conducted for literature on pressure injury prevention among orthopaedic patients in general wards. The types of literature included guidelines, clinical decisions, expert Consensus, evidence summaries, etc. The search period covered the time from the beginning of the database up to December 2023. The following databases and resources were systematically searched: Up To Date, JBI, NICE, WOCN, NZWCS, etc. RESULTS: Fifteen literature sources were included, comprising one clinical decision, eight guidelines, one systematic review, and one expert Consensus. In these sources, a comprehensive collection of 34 pieces of best evidence was formed across six key topics: risk assessment, position management, skin care, device used for device-related pressure injury, nutritional assessment, and support, as well as health education and training. Among the evidence gathered, a strong recommendation was made for 18 pieces, while the remaining 16 received a weak recommendation. This study provides a comprehensive synthesis of the most robust evidence on pressure injury prevention in orthopaedic patients, encompassing 34 pieces of evidence that can serve as valuable references for clinical practice. Before implementing this evidence, it is crucial to evaluate the specific contextual factors within different countries and medical institutions, as well as the facilitators and barriers influencing its application by healthcare professionals and patient's preferences. Furthermore, targeted evidence selection should be conducted through careful screening and subsequent adjustments in implementation, thereby offering a more scientifically grounded basis for clinical nursing practice. Future research endeavours should prioritise investigating strategies for effective evidence utilisation. The prevention of pressure injuries poses a significant challenge for orthopaedic patients. This study presents a synthesis of 34 pieces of best evidence to provide guidance on preventive measures for pressure injuries in orthopaedic patients. Adhering to and implementing these 34 pieces of evidence can effectively aid in preventing pressure injuries in clinical practice. This evidence encompasses risk assessment, position management, skin care, device usage for device-related pressure injuries, nutritional support and evaluation, and health education and training, establishing a comprehensive and systematic implementation process. Assessing the risk of pressure injuries during interventions serves as an essential prerequisite for developing effective strategies to prevent such injuries among orthopaedic patients. Ultimately, this study will offer valuable guidance to healthcare professionals worldwide regarding preventing pressure injuries in orthopaedic patients. Upon admission to the hospital, it is essential to conduct a risk assessment and implement evidence-based, individualised prevention measures for pressure ulcers in patients to prevent their occurrence. This study will provide valuable insights into preventing pressure injuries in orthopaedic patients admitted to orthopaedic wards for healthcare workers worldwide. The PRIMA manifest is utilised during the text preparation process. ES20245365.

Hemodynamic monitoring during weaning from mechanical ventilation in critically ill pediatric patients: a prospective observational study

BackgroundCardiovascular dysfunction is a significant factor contributing to weaning failure in mechanically ventilated children. Understanding the cardiopulmonary pathophysiological changes that occur during weaning is a prerequisite for the early recognition of weaning failure of cardiovascular origin. This study aimed to assess the effect of weaning trials on central hemodynamics and to identify the indices predictive of cardiac-related weaning failure.MethodsThis prospective observational study was conducted in the Pediatric Intensive Care Unit (PICU) and included mechanically ventilated patients aged between 2 and 30 months who were on minimal ventilatory settings and ready for weaning. Patients who were hemodynamically unstable, diagnosed with neuromuscular diseases, or diagnosed with cardiac diseases were excluded. Hemodynamic parameters were evaluated during weaning from ventilation via echocardiography and noninvasive cardiometry during pressure support (PS) ventilation and at the end of the spontaneous breathing trial (SBT).ResultsThe study included 50 patients, comprising 30 males (60%) and 20 females (40%) with ages ranging from 2 to 30 months. Echocardiography revealed a significant increase in the cardiac index (CI), tricuspid annular plane systolic excursion (TAPSE), and the E/A ratio at the end of SBT. Moreover, right ventricular systolic pressure (RVSP) significantly decreased. Noninvasive cardiometry revealed a significant increase in the index of contractility (ICON) and CI at the end of SBT (p-value = 0.023 and < 0.001, respectively). Of the 12 (25%) patients who failed their first extubation trial, they exhibited a significantly lower CI and TAPSE (p values = 0.001 and 0.001, respectively).ConclusionThis study identified that weaning from mechanical ventilation in children is associated with hemodynamic changes, which can impact weaning success and reveal potential ventricular dysfunction. Bedside echocardiography was found to detect cardiac dysfunctions during weaning, and noninvasive cardiometry was considered a reliable tool that supports echocardiography for detecting changing trends in CI in PICUs. However, accurate values should be confirmed by echocardiography.

Average volume-assured pressure support versus fixed pressure support in chronic hypercapnic respiratory failure: a systematic review and meta-analysis

Rationale: Chronic hypercapnic respiratory failure occurs due to alveolar hypoventilation resulting in carbon dioxide retention. This is commonly managed with noninvasive ventilation (NIV) with modalities including fixed pressure support and average volume-assured pressure support (AVAPS). However, there is limited information comparing outcomes with these two modes of ventilator support in the management of chronic hypercapnic respiratory failure. Objective: This review and meta-analysis analyze the outcomes with fixed pressure NIV versus average volume-assured pressure support NIV in managing chronic obstructive pulmonary disease (COPD) with chronic hypercapnic respiratory failure, focusing on patients’ perception of symptom burden and gas exchange based on arterial blood gases. Search methods: PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched; the latest search date was December 1, 2023. Inclusion criteria: randomized control trials and crossover studies in English in adults over the age of 19 with the diagnosis of COPD and chronic hypercapnic respiratory failure. Exclusion criteria: patients less than 19 years old, patients with acute exacerbations, and patients with central respiratory failure or neuromuscular disease. Outcomes included blood gas analysis after use of NIV measured in mmHg and patient perception of mental health, symptom burden, and comfort. Results for each outcome were analyzed in RevMan using an inverse variance statistical method with a fixed effect analysis. The final analysis included 7 studies with 252 participants. Results: The patients were 64 ± 9 years old. Baseline pulmonary function testing showed a forced expiratory volume in the first second (FEV1) of 34.6 ± 14.2 % predicted, consistent with severe COPD per GOLD criteria, and a baseline PaCO2 of 55.2 ± 9.2 mmHg. Primary outcomes for ventilation showed no statistical difference between AVAPS and fixed pressure support groups in PaCO2 (Odds Ratio [OR] -1.51; 95% Confidence Interval [CI]: -3.18, 0.16; p=0.08). Patient perceived outcomes were evaluated using several questionnaires, including St. George Respiratory Questionnaire (SGRQ), Short Form 36 Health Survey Questionnaire (SF-36), and Visual Analogue Scale (VAS). Comparable results were not available for all studies, but no statistically significant differences were found when comparing study results. Conclusions: There was little or no clinically significant difference between fixed pressure support and AVAPS in gas exchange. There are inadequate data to draw conclusions about the effect of fixed pressure support compared to AVAPS on patient perceived outcomes, such as comfort and symptom burden. No studies evaluated mortality benefit, cost effectiveness, or hospitalizations. Key words: COPD, chronic hypercapnic respiratory failure, non-invasive ventilation, average volume-assured pressure support ventilation

Spontaneous breathing trials should be adapted for each patient according to the critical illness. A new individualised approach: the GLOBAL WEAN study.

Spontaneous breathing trials (SBT) evaluate the patient's capacity to maintain inspiratory effort after extubation. SBT practices are heterogeneous and not individualised. The objective of this study was to assess which SBT best reproduces inspiratory effort after extubation in five critical illnesses. In this multicentre randomized cross-over study, adult intensive care unit patients under invasive mechanical ventilation for at least 24-h and ready for extubation, underwent three 15-min SBTs in random order: pressure support ventilation level of 7-cmH2O with positive end-expiratory pressure (PEEP) level of 0-cmH2O (PSV7PEEP0), PSV 0-cmH2O with PEEP 0-cmH2O (PSV0PEEP0) and T-piece trial. Primary outcome was the variation of pressure-time-product per minute (PTPmin) between each SBT and 20-min after extubation. Five categories of critical illnesses were selected: abdominal surgery, brain injury, chest trauma, chronic obstructive pulmonary disease (COPD) and miscellaneous. Five hundred measures of effort from 100 patients were analysed. PTPmin (cmH2O s/min, median and interquartile range, IQR) was 256 (208-321) after extubation, 192 (127-281) at the end of PSV7PEEP0 (p < 0.001 in comparison to after extubation), 291 (235-347) at the end of PSV0PEEP0 and 262 (198-338) at the end of T-piece (both no different from after extubation). One method of SBT in patients with brain injury (PSV0PEEP0), two in abdominal surgery (PSV0PEEP0 and T-piece) and miscellaneous patients (PSV7PEEP0 and T-piece) and all three methods in chest trauma and COPD exacerbation patients replicated reasonably accurately the postextubation effort to breathe. Unassisted SBTs, namely PSV0PEEP0 and T-piece trial, are the most appropriate to replicate the postextubation effort to breathe.

Spontaneous breathing trials: how and for how long?

Guidelines recommend systematic performance of a spontaneous breathing trial (SBT) before extubation in ICUs, the objective being to reduce the risk of reintubation. In theory, a more challenging SBT performed with a T-piece may further reduce the risk of reintubation, whereas a less challenging SBT performed with pressure-support ventilation (PSV) may hasten extubation. Recent findings show that a more challenging SBT with a T-piece or for a prolonged duration do not help to reduce the risk of reintubation. In contrast, a less challenging SBT with PSV is easier to pass than a T-piece, and may hasten extubation without increased risk of reintubation. Although SBT with PSV and additional positive end-expiratory pressure is indeed a less challenging SBT, further studies are needed to generalize such an easy trial in daily practice. Earlier screening for a first SBT may also decrease time to extubation without increased risk of reintubation. Lastly, reconnection to the ventilator for a short period after successful SBT facilitates recovery from the SBT-induced alveolar derecruitment. Several recent clinical trials have improved assessment of the most adequate way to perform SBT before extubation.

75 Lung ultrasound severity scores and its utility in predicting success of weaning off respiratory support in neonates born preterm

Abstract Background Preterm infants often require respiratory support in the newborn intensive care unit. Complete trial off around 30-34 weeks post-menstrual age (PMA) is by trial and error based on clinical and physiological variables. Lung ultrasound (LUS) is a reliable adjunct in the diagnosis and management of most neonatal lung conditions. However, its utility in accessing readiness for successful weaning off respiratory pressure support in preterm neonates has not been explored. Objectives To determine the utility of LUS severity score (LUS-sc) in predicting successful weaning off of respiratory pressure support after 32weeks CGA in neonates born ≤32 weeks gestational age (GA). Design/Methods Prospective cohort study involving preterm neonates born ≤32 weeks needing any respiratory pressure support modes, admitted to a single tertiary care center in Canada between Sept 2022-Sept 2023. Eligible neonates were assessed by LUS at two time points- LUS1 at 30-30 + 6 weeks for those born &amp;lt;30weeks GA and between 48-72hours of life for those born at 30-32 + 6 weeks GA; LUS2 within 12hours prior to trial off respiratory pressure support to room air or low flow after 32weeks PMA. LUS were scored for disease severity by two independent reviewers using the LUS-sc by Brat et al. Receiver operator characteristics (ROC) curves analyzed the reliability of LUS-sc to predict the successful cessation of respiratory pressure support to room air or low flow post LUS2. Results Of 50 preterm neonates included in the study, 32 (64%) were successfully weaned from pressure support after LUS2 at a mean (SD) GA of 33.03 (0.29). The mean (SD) GA at birth was 28.78 (0.46) in the successful group and 27.78 (0.62) in the unsuccessful group (p=0.197). The mean (SD) LUS-sc for LUS2 at which cessation of support was possible was significantly lower from those who failed [6.95(0.33) vs 8.69(0.55), p=0.006] (Table 1). The ROC curve (Figure 1) showed AUC of 0.717 (95%CI=0.56-0.86), for a cut-off of LUS-sc of 7.75, with sensitivity of 0.75 (95%CI=0.60-0.90) and specificity of 0.61 (95%CI=0.38-0.84). Independent of GA at birth and at respiratory pressure support trial off, LUS-sc ≤8 was associated with an increased odd of cessation of support by 9.0 (95%CI=1.9-42.6), p=0.005, and each additional week of GA at first trial off increased the odds of cessation by 2.2 (95%CI=1.1-4.4), p=0.031. Conclusion LUS is a reliable tool to assess readiness for successful non-invasive respiratory pressure support trial off. A LUS-sc ≤8 was associated with higher successful weaning off of non-invasive pressure support after 32weeks GA.