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Effect of protective ventilation throughout the intubation period on perioperative oxygenation in patients undergoing MIDCABG: a randomised controlled trial.

INTRODUCTION: Minimally invasive direct coronary artery bypass grafting (MIDCABG) requires prolonged one-lung ventilation (OLV), increasing postoperative pulmonary complications (PPCs) risk. We investigated whether protective lung ventilation (PLV) throughout intubation benefits MIDCABG patients. METHODS: In this single-center randomized study, MIDCABG patients received PLV (low tidal volume of 6-8&#x2009;mL&#xb7;kg-1, PEEP of 6&#x2009;cm H2O, alveolar recruitment maneuvers) or conventional mechanical ventilation (CMV, tidal volume of 8-10&#x2009;mL&#xb7;kg-1, without PEEP or maneuvers) from tracheal intubation to extubation. The primary outcome was perioperative oxygenation, assessed by the PaO2/FiO2 ratio. RESULTS: Sixty patients (n = 30 per group) were enrolled. Compared with CMV, PLV improved PaO2/FiO2 ratios (mean difference at OLV60: 34.56&#x2009;mmHg; 95% CI: 11.78-57.33; p&#x2009;<&#x2009;0.01), shortened median durations of postoperative mechanical ventilation (median difference: -4.5&#x2009;h, 95% CI: -8.5 to -0.5; p&#x2009;=&#x2009;0.013) and hospital stay (median difference: -3.0&#x2009;days, 95% CI: -5.0 to -1.0; p&#x2009;=&#x2009;0.019). PLV also reduced driving pressure, airway pressure and intrapulmonary shunt during OLV (all p&#x2009;<&#x2009;0.05). Desaturation occurred in 23.3% of CMV patients and 13.3% of PLV patients (p&#x2009;=&#x2009;0.506). Hemodynamic parameters were generally comparable between groups, except for lower MPAP and PVRI in the PLV group during OLV and after ICU admission (p&#x2009;<&#x2009;0.05). The incidence of PPCs did not differ between groups. CONCLUSIONS: In patients undergoing MIDCABG, PLV applied throughout intubation improved perioperative oxygenation and shortened the duration of postoperative mechanical ventilation and hospital stay, but did not reduce PPCs. CLINICAL TRIAL REGISTRATION: ChiCTR1900022005.

Humans

Impact of real-time respiratory function monitoring on neonatal mask ventilation training: a multicentre simulation-based crossover study.

OBJECTIVE: To evaluate whether visibility of respiratory function monitor (RFM) feedback improves mask ventilation performance and influences subsequent ventilation performance during neonatal resuscitation training. DESIGN: multicentre randomised crossover simulation study. PARTICIPANTS: Healthcare professionals involved in neonatal resuscitation training across participating centres. INTERVENTION: Participants performed positive pressure ventilation (PPV) on both term and premature manikins under two conditions: with visible RFM feedback and with the display masked. The order of feedback visibility was randomised. Each participant completed ventilation assessments in both conditions. MAIN OUTCOME MEASURES: Primary outcomes were expired tidal volume (Vte) and mask leak (%). The proportion of breaths within the target Vte range (4-8&#x2009;mL/kg) was calculated as a performance indicator. Secondary outcomes included variability in Vte and mask leak to assess ventilation stability between conditions. RESULTS: Visible RFM feedback was associated with lower mask leak and improved ventilation stability in the preterm manikin and with tidal volumes entering the target range in the term manikin. Participants initially ventilated with visible feedback maintained performance after feedback removal, suggesting a carry-over learning effect. CONCLUSION: In this multicentre crossover simulation study, visible RFM feedback was associated with changes in mask ventilation performance and evidence of a carry-over learning effect following feedback removal. Real-time visibility of respiratory parameters may strengthen neonatal resuscitation training.

Humans

Impact of neoprene wetsuits on lung volumes and work of breathing: implications for military diver safety and performance.

INTRODUCTION: Neoprene wetsuits may impose mechanical constraints on the chest wall, potentially altering respiratory function. This study investigated the impact of neoprene wetsuits on lung volumes, airway mechanics, and work of breathing (WOB) in healthy male divers. METHODS: A randomised crossover trial was conducted with 31 male divers at the Royal Netherlands Navy Diving Medical Centre. Participants underwent pulmonary function testing, including spirometry, body plethysmography, the forced oscillation technique (FOT), and diffusion capacity measurements, both with and without a hoodless standardised 5 mm neoprene full body wetsuit with a neoprene neck seal. Primary outcomes included changes in forced vital capacity (FVC), functional residual capacity (FRC), airway resistance (Raw), reactance (Xrs), and WOB. RESULTS: Wearing a neoprene wetsuit led to statistically significant reductions in FVC (2.8%, P < 0.05), forced expiration in one second (2.9%, P < 0.05), FRC (4.0%, P < 0.05), and expiratory reserve volume (10.9%, P < 0.05), alongside increases in inspiratory capacity and tidal volume. Raw increased significantly (P < 0.05), while the FOT revealed altered airway mechanics, evidenced by increased Xrs at multiple frequencies (P < 0.05). Diffusion capacity remained unchanged, suggesting preserved alveolar-capillary function. CONCLUSIONS: Neoprene wetsuits induce mechanically restrictive effects on the chest wall, reducing static and dynamic lung volumes and increasing WOB. While these changes may not be clinically relevant at rest, their impact needs to be determined during strenuous or prolonged dives, particularly when combined with other equipment that limits thorax excursions. Future research should explore the effects of the military 5 mm wetsuit under immersed conditions to better understand their operational impact on diver performance and safety.

Male

Interventions with a significant mortality difference in acute respiratory distress syndrome: A systematic review and comparison with Guidelines.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) has a high mortality rate. European Society of Intensive Care Medicine (ESICM) and American Thoracic Society (ATS) Guidelines are the worldwide reference for clinicians in management of ARDS. Mortality represents one of the most important outcomes in intensive care practice and randomized controlled trials (RCTs) the highest level of evidence. We compared Guidelines recommendations with RCT results to highlight differences and find potential new therapeutic opportunities. METHODS: We performed a systematic review of all RCTs reporting a statistically significant mortality difference in ARDS and a subsequent comparison with ESICM and ATS Guidelines recommendations. RESULTS: We identified 33 RCTs and 23 interventions with mortality difference in ARDS patients. Seven interventions relate to invasive ventilation strategies, two to noninvasive ventilation strategies, one to extracorporeal membrane oxygenation (ECMO), 12 to drugs and one to nutritional support. In 25/33 (76%) RCTs the intervention was associated with mortality reduction and in 8/33 with mortality increase (24%). Multicenter studies were 24/33 (73%) while blinding was adopted in 19/33 (58%) studies. Guidelines recommendations supported by RCTs with mortality impact include: the use of low tidal volume ventilation, prone positioning, venovenous ECMO, steroids and the avoidance of high frequency oscillatory ventilation. Eight of the interventions identified were not mentioned by Guidelines but demonstrated reduced mortality, and five further interventions demonstrated increased mortality. CONCLUSIONS: This systematic review highlights potential gaps between RCTs results and Guidelines that could be used to plan future research or highlight topics to be discussed in future Guidelines.

Humans

Comparison of VCV and PCV-VG modes on diaphragmatic function in diabetic patients undergoing laparoscopic colorectal surgery: a prospective randomized controlled study.

BACKGROUND: Diabetic patients are prone to induce diaphragmatic weakness, which can lead to postoperative pulmonary complications (PPCs). The optimal mechanical ventilation mode may potentially improve postoperative diaphragmatic function. This study evaluates the effects of two ventilation modes under driving pressure-guided ventilation strategy on diaphragmatic function, as assessed by diaphragm thickening fraction (DTF) and diaphragm excursion (DE), in diabetic patients following laparoscopic colorectal surgery. METHODS: Eighty patients diagnosed with Type II diabetes scheduled for elective laparoscopic colorectal surgery, were randomly allocated to either the pressure-controlled volume-guaranteed ventilation (PCV-VG) group (Group P) or the volume-controlled ventilation (VCV) group (Group V) during surgery. The primary outcome was diaphragmatic function assessed during both tidal breathing and maximal inspiratory effort after surgery. Secondary outcomes included intraoperative mechanical power, PPCs, and other complications. RESULTS: A total of eighty patients were included in the final analysis. The averaged area under the curve (AUC) for mechanical power during ventilation was significantly lower in Group P than in Group V (p&#x2009;=&#x2009;0.002). PCV-VG significantly improved both DE and DTF within the first two days post-surgery (AUCDEtidal: p&#x2009;=&#x2009;0.088, AUCDTFtidal: p&#x2009;=&#x2009;0.004, AUCDEmax: p&#x2009;=&#x2009;0.029, AUCDTFmax: p&#x2009;=&#x2009;0.017). Postoperative diaphragmatic weakness was less frequent in Group P than in Group V (p&#x2009;=&#x2009;0.019). However, there was no difference in the incidence of PPCs between the two groups (p&#x2009;=&#x2009;0.155). CONCLUSION: PCV-VG mode can reduce intraoperative mechanical power, better preserve postoperative diaphragmatic function. However, these improvements did not translate into clinical benefits, as evidenced by the lack of reduction in the incidence of PPCs.

Humans

Single-slice Functional Lung MRI During Metronome-Paced Tachypnea Detects Changes in Regional Ventilation Dynamics After a Single Dose of Dual Bronchodilator Treatment in COPD.

Dual long-acting bronchodilators are a standard treatment in chronic obstructive pulmonary disease (COPD), aimed at alleviating dyspnea, improving exercise tolerance, and preventing exacerbations. Metronome-paced tachypnea (MPT) offers a feasible alternative to exercise testing for the evaluation of dynamic hyperinflation (DH) in COPD. Because MPT can be performed during MRI, its combination with single-slice phase-resolved functional lung (PREFUL) MRI provides a promising approach to investigate changes in regional ventilation dynamics induced by DH. This approach was evaluated in a randomized, investigator-blinded, placebo-controlled, single-dose (SD) crossover trial with a two-week extension of once daily dual bronchodilator medication, in which patients with stable COPD underwent PREFUL MRI during resting tidal breathing (RTB) and during MPT. During RTB, no significant improvements in MRI-derived parameters were observed after SD treatment compared with placebo. During MPT, however, regional ventilation, flow-volume loop correlation, its defect percentage, and end-expiratory lung area improved significantly after SD treatment compared to the placebo scan (all p&#x2009;<&#x2009;0.02). After multi-dose treatment, five out of six measured parameters improved during MPT, when compared to the baseline scan without bronchodilator treatment (all p&#x2009;<&#x2009;0.03). In contrast to RTB, PREFUL MRI during MPT was able to detect changes in COPD patients already after SD treatment. The combination of MPT and PREFUL MRI represents a promising method to evaluate the effects of dual bronchodilators on regional ventilation dynamics and hyperinflation.

Humans