Pressure Support Research Articles

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

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 < 0.001), hs-Troponin T (β = 3.391, p < 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 < 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 < 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.

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.

Inter-lung asymmetrical airway closure cause insufflation delay between lungs in acute hypoxemic respiratory failure

BackgroundElectrical Impedance Tomography (EIT) can quantify ventilation in the two lungs and be used to measure the airway opening pressure (AOP) of each lung. Asymmetrical AOPs can cause inter-lung insufflation delay.ObjectivesTo assess the relation between AOP asymmetry and inter-lung insufflation delay at different PEEP levels.MethodsPatients with acute hypoxemic respiratory failure and airway closure were included. Low-flow pressure-volume curves and EIT signal were recorded during controlled ventilation and for some patients in pressure support ventilation.Results23 patients were studied, 22 patients had ARDS, 9 patients had asymmetrical airway closure with an AOP of 10 [6–13] cmH20 in the sicker lung (AOPsicker) vs. 5 [3–9, ] cmH20 in the healthier lung. During a low flow inflation, the inter-lung inflation delay was 0 [0-112]ms vs. 1450 [375–2400]ms in patients without or with asymmetrical AOPs, p < 0.0001. This delay was correlated to the difference of AOP between the 2 lungs, Spearman R2 = 0.800, p < 0.0001. During tidal ventilation, median delay was 0 [0–62] ms vs. 150 [50–355] ms in patients without vs. with asymmetry, p = 0.019. Setting PEEP at the crossing point of a decremental EIT-based PEEP trial decreased the inter-lung insufflation delay. During pressure support insufflation delay could still be measured and was reduced by increasing PEEP from 5 to 10 cmH2O in patient with asymmetrical lung injury.ConclusionIn asymmetrical airway closure, titrating PEEP can minimize inter-lung insufflation delay and can be monitored by EIT. Reducing the delay and reducing ventilation asymmetry is also feasible during pressure support ventilation when low flow inflation curves cannot be performed.

Stronger association of intact angiotensinogen with mortality than lactate or renin in critical illness: post-hoc analysis from the VICTAS trial

Sepsis and septic shock remain global healthcare problems associated with high mortality rates despite best therapy efforts. Circulating biomarkers may identify those patients at risk for poor outcomes, however, current biomarkers, most prominently lactate, are non-specific and have an inconsistent impact on prognosis and/or disease management. Activation of the renin-angiotensin- system (RAS) is an early event in sepsis patients and elevated levels of circulating renin are more predictive of worse outcomes than lactate. The precursor protein Angiotensinogen is another key component of the circulating RAS; it is the only known substrate for renin and the ultimate source of the vasopressor Angiotensin II (Ang II). We postulate that lower Angiotensinogen concentrations may reflect a dysfunctional RAS characterized by high renin concentrations but attenuated Ang II generation, which is disproportionate to the high renin response and may compromise adequate support of blood pressure and tissue perfusion in septic patients. The current study compared the association between serum Angiotensinogen with mortality to that of lactate and renin in the VICTAS cohort of sepsis patients at baseline (day 0) by receiver operating characteristic (ROC) and Kaplan–Meier curve analyses. Serum concentration of Angiotensinogen was more strongly associated with 30-day mortality than either the serum concentrations of renin or lactate in sepsis patients. Moreover, the clinical assessment of Angiotensinogen may have distinct advantages over the typical measures of renin. The assessment of intact Angiotensinogen may potentially facilitate more precise therapeutic approaches (including exogenous angiotensin II) to restore a dysfunctional RAS and improve patient outcomes. Additional prospective validation studies are clearly required for this biomarker in the future.

Predictive Value of Diaphragm and Lung Ultrasonography for Weaning Failure in Critically Ill Patients with Acute Respiratory Failure Due to COVID-19 Pneumonia.

This study analyzed weaning characteristics and assessed the association of clinical and ultrasonographic indices-maximum inspiratory pressure (MIP), rapid shallow breathing index (RSBI), peak flow expiratory (PFE), diaphragm-thickening fraction (DTF), diaphragm thickness (DT), diaphragm excursion (DE), diaphragm-RSBI (D-RSBI), and lung ultrasound (LUS) patterns-with weaning failure. This retrospective cohort study included critically ill COVID-19 patients aged 18 and older who had been on invasive mechanical ventilation for at least 48 h and undergoing weaning. Exclusion criteria included absence of ultrasound assessments, neuromuscular diseases, and chronic cardio-respiratory dysfunction. Among 61 patients, 44.3% experienced weaning failure, 27.9% failed the spontaneous breathing trial (SBT), 16.4% were re-intubated within 48 h, and 28% required tracheostomy. Weaning failure was associated with prolonged ventilation (29 vs. 7 days, p < 0.001), extended oxygen therapy, longer ICU stays, and higher ICU mortality. These patients had higher pressure support, lower oxygenation levels, a higher RSBI, and a lower MIP. While PEF, DTF, DE, and D-RSBI showed no significant differences, both right and left diaphragm thicknesses and the inspiratory thickness of the left diaphragm were reduced in failure cases. LUS scores were significantly higher before and after SBT in the failure group. Bivariate analysis identified RSBI [OR = 1.04 (95% CI = 1.01-1.07), p = 0.010], MIP [OR = 0.92 (95% CI = 0.86-0.99), p = 0.018], and LUS [OR = 1.15 (95% CI = 0.98-1.35), p = 0.025] as predictors of weaning failure; however, these associations were not confirmed in multivariate analysis. Ultrasound provides supplementary information during weaning, but no definitive association between ultrasound indices and weaning failure was confirmed in this study.

Frequency of Screening and Spontaneous Breathing Trial Techniques

The optimal screening frequency and spontaneous breathing trial (SBT) technique to liberate adults from ventilators are unknown. To compare the effects of screening frequency (once-daily screening vs more frequent screening) and SBT technique (pressure-supported SBT with a pressure support level that was >0-≤8 cm H2O and a positive end-expiratory pressure [PEEP] level that was >0-≤5 cm H2O vs T-piece SBT) on the time to successful extubation. Randomized clinical trial with a 2 × 2 factorial design including critically ill adults who were receiving invasive mechanical ventilation for at least 24 hours, who were capable of initiating spontaneous breaths or triggering ventilators, and who were receiving a fractional concentration of inspired oxygen that was 70% or less and a PEEP level of 12 cm H2O or less. Recruitment was between January 2018 and February 2022 at 23 intensive care units in North America; last follow-up occurred October 18, 2022. Participants were enrolled early to enable protocolized screening (more frequent vs once daily) to identify the earliest that patients met criteria to undergo pressure-supported or T-piece SBT lasting 30 to 120 minutes. Time to successful extubation (time when unsupported, spontaneous breathing began and was sustained for ≥48 hours after extubation). Of 797 patients (198 in the once-daily screening and pressure-supported SBT group, 204 in once-daily screening and T-piece SBT, 195 in more frequent screening and pressure-supported SBT, and 200 in more frequent screening and T-piece SBT), the mean age was 62.4 (SD, 18.4) years and 472 (59.2%) were men. There were no statistically significant differences by screening frequency (hazard ratio [HR], 0.88 [95% CI, 0.76-1.03]; P = .12) or by SBT technique (HR, 1.06 [95% CI, 0.91-1.23]; P = .45). The median time to successful extubation was 2.0 days (95% CI, 1.7-2.7) for once-daily screening and pressure-supported SBT, 3.1 days (95% CI, 2.7-4.8) for once-daily screening and T-piece SBT, 3.9 days (95% CI, 2.9-4.7) for more frequent screening and pressure-supported SBT, and 2.9 days (95% CI, 2.0-3.1) for more frequent screening and T-piece SBT. An unexpected interaction between screening frequency and SBT technique required pairwise contrasts that revealed more frequent screening (vs once-daily screening) and pressure-supported SBT increased the time to successful extubation (HR, 0.70 [95% CI, 0.50-0.96]; P = .02). Once-daily screening and pressure-supported SBT (vs T-piece SBT) did not reduce the time to successful extubation (HR, 1.30 [95% CI, 0.98-1.70]; P = .08). Among critically ill adults who received invasive mechanical ventilation for more than 24 hours, screening frequency (once-daily vs more frequent screening) and SBT technique (pressure-supported vs T-piece SBT) did not change the time to successful extubation. However, an unexpected and statistically significant interaction was identified; protocolized more frequent screening combined with pressure-supported SBTs increased the time to first successful extubation. ClinicalTrials.gov Identifiers: NCT02399267 and NCT02969226.

Perioperative assessment of diaphragmatic dysfunction in cardiac surgery patients and its effect on outcome; a prospective observational study

Objectives: While the assessment of the diaphragm in different clinical scenarios is quite frequent, there remains a scarcity of studies focused on assessing diaphragm dysfunction using ultrasound in cardiac surgery patients. We investigated the impact of cardiopulmonary bypass (CPB) surgery on diaphragm function and evaluated its effects on mechanical ventilation. Methodology: A prospective cohort study, on 100 consecutive adult cardiac surgery patients, was conducted at National Heart Institute. Diaphragmatic displacement (DD) or excursion and diaphragmatic thickening fraction (DTF) were measured using motion-mode ultrasound during quite normal breathing pre-operatively (the day before surgery) and post-operatively on mechanical ventilation, while the patient was fully conscious and spontaneously breathing on continuous positive airway pressure (CPAP) mode + pressure support 10 cmH2O. Then, the results were correlated to CBP time and important patient outcomes. Results: Post-operative DD was significantly less as compared to the pre-operative reading; (1.39 ± 0.42 cm vs. 2.3 ± 0.52 cm; P &lt; 0.001), as was DTF (23% ± 10% vs. 40% ± 13%; P &lt; 0.001). The incidence of diaphragmatic dysfunction post-cardiac surgery was 17% by the definition of DD &lt; 1 cm, and 49% by the definition of DTF ≤ 20%. DD was positively correlated with CBP time, as well as total ventilation time and ICU stay, indicating a negative impact on overall patient outcomes. Conclusion: The results suggest that diaphragmatic dysfunction is positively correlated with CPB time, total ventilation time and ICU stay, underscoring the importance of monitoring diaphragmatic function in post-operative patients, who are difficult to wean from mechanical ventilation with apparently normal chest X-ray, particularly those with prolonged CPB time. Keywords: cardiac surgery; cardiopulmonary bypass; diaphragm dysfunction; diaphragmatic displacement; diaphragm ultrasound; mechanical ventilation. Citation: Omara ISM, Nagi HK, Mohamed KAA, Abd El Haq HH, Awdallah FF. Perioperative assessment of diaphragmatic dysfunction in cardiac surgery patients and its effect on outcome; a prospective observational study. Anaesth. pain intensive care 2024;28(5):816−823; DOI: 10.35975/apic.v28i5.2555 Received: June 28, 2024; Reviewed: September 04, 2024; Accepted: September 06, 2024

Use of prototype bi-nasal prongs for noninvasive ventilation in foals.

Noninvasive ventilation (NIV) provides effective respiratory support in foals, but face masks are poorly tolerated and associated with hypercapnia. Bi-nasal prongs might be a more effective device interface in foals. To compare bi-nasal prongs and masks for NIV in foals with pharmacologically induced respiratory insufficiency. Six healthy foals. In a randomized cross-over study, sedated foals received NIV delivered by mask or bi-nasal prongs, with the treatment repeated using the alternative device interface after a 3-day rest period. After periods of spontaneous ventilation through the allocated interface, with and without supplementary O2 (T2-T3), foals were subject to 10-minute treatment periods of NIV at different pressure support (5 or 10 cmH2O) and end-expiratory pressure settings (5 or 10 cmH2O), with and without supplementary O2 (T4-T7). Vital signs, arterial blood gases, spirometry, and gas exchange data were measured in the final 2 minutes of each treatment window. Bi-nasal prongs were well tolerated and required less manual positioning or monitoring compared to the mask. Partial pressure of carbon dioxide did not increase during NIV with bi-nasal prongs and was lower than observed with masks (mean difference, 8.2 mmHg [95% confidence interval, 4.1-12.2 mmHg] at T6). Oxygenation and respiratory mechanics were improved in all foals and not different between device interfaces. Nasal prongs were well tolerated, had similar effects on respiratory function, and appeared to ameliorate hypercapnia observed previously during NIV in foals.

Heterogeneous impact of Sighs on mortality in patients with acute hypoxemic respiratory failure: insights from the PROTECTION study.

Sigh breaths may impact outcomes in acute hypoxemic respiratory failure (AHRF) during assisted mechanical ventilation. We investigated whether sigh breaths may impact mortality in predefined subgroups of patients enrolled in the PROTECTION multicenter clinical trial according to: 1.the physiological response in oxygenation to Sigh (responders versus non-responders) and 2.the set levels of positive end-expiratory pressure (PEEP) (High vs. Low-PEEP). If mortality differed between Sigh and No Sigh, we explored physiological daily differences at 7-days. Patients were randomized to pressure support ventilation (PSV) with Sigh (Sigh group) versus PSV with no sigh (No Sigh group). (1) Sighs were not associated with differences in 28-day mortality in responders to baseline sigh-test. Contrarily-in non-responders-56 patients were randomized to Sigh (55%) and 28-day mortality was lower with sighs (17%vs.36%, log-rank p = 0.031). (2) In patients with PEEP > 8cmH2O no difference in mortality was observed with sighs. With Low-PEEP, 54 patients were randomized to Sigh (48%). Mortality at 28-day was reduced in patients randomised to sighs (13%vs.31%, log-rank p = 0.021). These findings were robust to multivariable adjustments. Tidal volume, respiratory rate and ventilatory ratio decreased with Sigh as compared with No Sigh at 7-days. Ventilatory ratio was associated with mortality and successful extubation in both non-responders and Low-PEEP. Addition of Sigh to PSV could reduce mortality in AHRF non-responder to Sigh and exposed to Low-PEEP. Results in non-responders were not expected. Findings in the low PEEP group may indicate that insufficient PEEP was used or that Low PEEP may be used with Sigh. Sigh may reduce mortality by decreasing physiologic dead space and ventilation intensity and/or optimizing ventilation/perfusion mismatch. ClinicalTrials.gov; Identifier: NCT03201263.

Estimation of transpulmonary driving pressure using a lower assist maneuver (LAM) during synchronized ventilation in patients with acute respiratory failure: a physiological study

BackgroundWe previously showed in animals that transpulmonary driving pressure (PL) can be estimated during Neurally Adjusted Ventilatory Assist (NAVA) and Neural Pressure Support (NPS) using a single lower assist maneuver (LAM). The aim of this study was to test the LAM-based estimate of PL (PL_LAM) in patients with acute respiratory failure.MethodsThis was a prospective, physiological, and interventional study in intubated patients with acute respiratory failure. During both NAVA and simulated NPS (high and low levels of assist), a LAM was performed every 3 min by manually reducing the assist to zero for one single breath (by default, ventilator still provides 2 cmH2O). Following NAVA and NPSSIM periods, patients were sedated and passively ventilated in volume control and pressure control ventilation, to obtain PL during controlled mechanical ventilation (PL_CMV). PL using an esophageal balloon (PL_Pes) was also compared to PL_LAM and PL_CMV. We measured diaphragm electrical activity (Edi), ventilator pressure (PVent), esophageal pressure (Pes) and tidal volume. PL_LAM and PL_Pes were compared to themselves, and to PL_CMV for matching flows and volumes.ResultsTen patients were included in the study. For the group, PL_LAM was closely similar to PL_CMV, with a high correlation (R2 = 0.88). Bland–Altman analysis revealed a low Bias of 0.28 cmH2O, and 1.96SD of 5.26 cmH2O. PL_LAM vs PL_Pes were also tightly related (R2 = 0.77).ConclusionThis physiological study in patients confirms our previous pre-clinical data that PL_LAM is as good an estimate as PL_Pes to determine PL, in spontaneously breathing patients on assisted mechanical ventilation.Trial registration The study was registered at clinicaltrials.gov (ID NCT05378802) on November 6, 2021

Real-world effectiveness and safety of handheld ultrasound in pleural procedures.

The use of ultrasound for pleural procedures is associated with a decreased risk of complications. Handheld ultrasounds allow for easier evaluation of the pleural space. Limited data exists for the use of such devices for pleural procedures. The primary objective of our study was to assess the effectiveness and safety of handheld ultrasound for pleural procedures. We performed a prospective observational study, including all consecutive patients who underwent pleural procedures using the handheld ultrasound between September 2021 and November 2023. A total of 332 pleural procedures were attempted with handheld ultrasound, of which 329 pleural procedures (99.1%) were successfully performed. The median volume of fluid drained was 500 (interquartile range: 300-800). Thoracentesis was performed in 127 patients (38.5%), tube thoracostomy in 179 patients (54.4%), and medical thoracoscopy in 23 patients (7.0%). Exudative pleural effusions were found in 264 patients (80.0%), of which 152 (46.2%) were determined to be due to infectious etiologies. A total of 4 (1.2%) patients had a complication due to the procedure. 2 patients (0.6%) had a pneumothorax, while 2 patients (0.6%) developed a hemothorax. A total of 101 patients had either low platelets (<50×109/L) or use of anti-platelet or anti-coagulant drugs. 128 patients (38.8%) were on positive pressure support during the pleural procedure. Our study shows that handheld ultrasounds are effective and safe for pleural procedures, including cases with septated pleural effusions and patients on anti-platelet or anti-coagulant drugs.

Changes in the intestinal microbiome of the preterm baby associated with stopping non-invasive pressure support: a prospective cohort study

BackgroundIntestinal dysbiosis is implicated in the pathogenesis of necrotising enterocolitis and late-onset sepsis in preterm babies. The provision of non-invasive positive pressure ventilation is a common clinical intervention in preterm...

Evaluation of Resource and Environmental Carrying Capacity at Provincial Level in China Using a Pressure–Support–Adjustment Ternary System

Resources and environment are essential elements of social and economic development. Whether the current resources and environment can sufficiently support economic and social development is an important scientific issue. Existing studies have not reached a consensus on the definition, assessment, and forewarning methods of resource and environmental carrying capacity (RECC). Therefore, this study puts forward a ternary theoretical system of RECC from the perspective of pressure, support, and adjustment, constructs a novel evaluation indices system of RECC, introduces a ternary evaluation model, and proposes a hierarchical forewarning method of RECC with a threshold of 1. Furthermore, an empirical demonstration of 31 provinces in China is presented. The results show that: (1) the average RECC index of 31 areas revealed a downward trend from 2012 to 2021, indicating the gradually improving RECC; (2) the RECC indices of central areas were always high, which manifests the poor RECC; (3) the number of provinces with RECC at Alert Level III decreased from 18 to 7, and the number of provinces at Non-Alert Level increased from 6 to 8.

Ventilator performances for non-invasive ventilation: a bench study

IntroductionA wide range of recent ventilators, dedicated or not, is available for non-invasive ventilation (NIV) in respiratory or intensive care units (ICU). We conducted a bench study to compare their...