Improved Lung Compliance Research Articles

Hemodynamic instability in the transitional period after birth

It is not uncommon for a patient to experience hemodynamic instability following birth. This is due to the fact that the transitional period requires dramatic cardiorespiratory changes. When it goes well, improved lung compliance and successful transition to the postnatal circulation is seen. However, it is highly beneficial that clinicians have a solid understanding of all of the required changes, the unique aspects of the neonatal myocardium, and the influence of cardiovascular disease on normal adaptive mechanisms. In this manuscript, we will review the physiology of the normal postnatal circulatory adaptation, the unique characteristics of the neonatal myocardium and how it behaves in states of altered loading conditions, and the impact of hemodynamic disease states on health and wellbeing during the immediate postnatal time-period.

A stepwise lung recruitment maneuver using I-gel can improve respiratory parameters: A prospective observational study.

I-gel has been used in various clinical situations. The study investigated alterations in respiratory parameters following a stepwise lung recruitment maneuver (LRM) using the i-gel. The research involved 60 patients classified as American Society of Anesthesiologists class I-II, aged 30 to 75 years, undergoing elective urologic surgery. Various respiratory parameters, including lung compliance, airway resistance, leak volume, airway pressure, and oxygen reserve index, were recorded at different time points: before LRM, immediately after LRM, and at 5, 15, and 30 minutes after LRM, as well as at the end of the surgery. The primary outcome was to assess an improvement in lung compliance. Dynamic lung compliance (mean ± SD) was significantly increased from 49.2 ± 1.8 to 70.15 ± 3.2 mL/cmH2O (P < .05) after LRM. Static lung compliance (mean ± SD) was increased considerably from 52.4 ± 1.7 to 65.0 ± 2.5 mL/cmH2O (P < .05) after the LRM. Both parameters maintained a statistically significant increased status for a certain period compared to baseline despite a decreased degree of increment. Airway resistance (mean ± SD) was significantly reduced after the LRM from 12.05 ± 0.56 to 10.41 ± 0.64 L/cmH2O/s (P < .05). Stepwise LRM using i-gel may improve lung compliance and airway resistance. Repeated procedures could lead to prolonged improvements in respiratory parameters.

Driving Pressure During Mechanical Ventilation of Acute Respiratory Distress Syndrome

Background: Driving pressure has been identified as a more accurate indicator of mortality risk than low tidal volume (VT) and pulmonary compliance (Ppl). It was also noted that when this pressure surpasses the 18 cm H2O mark, there is a significant elevation in the relative risk of death. This study aimed to evaluate the effect of driving pressure guided ventilation in acute respiratory distress syndrome (ARDS). Patients and Methods: The study included 64 subjects selected from the respiratory intensive care unit (RICU) of Al-Azhar University Hospital (Damietta). All participants received management through a protective lung strategy that was informed by driving Pressure. The study outcomes included 1). Determination of weaning categories; 2). Adverse events; 3). Length of ICU stay and duration of mechanical ventilation; 4). Mechanical Ventilation-free days, and 5). Organ/s dysfunction. Results: The commonest cause of admission was pneumonia (36%), and least percentage was septic shock (1.6%). The median ICU stay was 7 days (4 to 25 days) and weaning success rate was 76.6% with mortality rate of 23.4%. The severity was mainly severe (40.6%) and moderate (31.2%). Driving pressure at day 1 of ≤ 21 had sensitivity of 97.96%, specificity of 80.0% and area under curve (AUC) of 0.952. The driving pressure was significantly increased in cases with failure weaning than the success weaning (24.67 ± 1.05 vs 16.86 ± 1.24, respectively). In addition, it was significantly increased in died than alive patients. There was progressive significant increase of driving pressure from mild to moderate to severe cases. Pneumothorax was recorded among 9.4% and pleural effusion was recorded for 7.8% of patients. Conclusion: Use of driving pressure guided ventilation in patients with ARDS improves lung compliance, decreases the duration of mechanical ventilation and the length of ICU stay. Driving pressure &lt; 21 can predict mortality.

Contribution of electrical impedance tomography to personalize positive end-expiratory pressure under ECCO2R

Extracorporeal Carbon Dioxide Removal (ECCO2R) is used in acute respiratory distress syndrome (ARDS) patients to facilitate lung-protective ventilatory strategies. Electrical Impedance Tomography (EIT) allows individual, non-invasive, real-time, bedside, radiation-free imaging of the lungs, providing global and regional dynamic lung analyses. To provide new insights for future ECCO2R research in ARDS, we propose a potential application of EIT to personalize End-Expiratory Pressure (PEEP) following each reduction in tidal volume (VT), as demonstrated in an illustrative case. A 72-year-old male with COVID-19 was admitted to the ICU for moderate ARDS. Monitoring with EIT was started to determine the optimal PEEP value (PEEPEIT), defined as the intersection of the collapse and overdistention curves, after each reduction in VT during ECCO2R. The identified PEEPEIT values were notably low (< 10 cmH2O). The decrease in VT associated with PEEPEIT levels resulted in improved lung compliance, reduced driving pressure and a more uniform ventilation pattern. Despite current Randomized Controlled Trials showing that ultra-protective ventilation with ECCO2R does not improve survival, the applicability of universal ultra-protective ventilation settings for all patients remains a subject of debate. Inappropriately set PEEP levels can lead to alveolar collapse or overdistension, potentially negating the benefits of VT reduction. EIT facilitates real-time monitoring of derecruitment associated with VT reduction, guiding physicians in determining the optimal PEEP value after each decrease in tidal volume. This original description of using EIT under ECCO2R to adjust PEEP at a level compromising between recruitability and overdistention could be a crucial element for future research on ECCO2R.

Pressure-controlled versus Volumecontrolled Ventilation during One Lung Ventilation for Empyema Thoracis: A Randomised Control Trial

Pressure-controlled versus Volumecontrolled Ventilation during One Lung Ventilation for Empyema Thoracis: A Randomised Control Trial

Effect of intravenous vs. inhaled penehyclidine on respiratory mechanics in patients during one-lung ventilation for thoracoscopic surgery: a prospective, double-blind, randomised controlled trial

BackgroundMinimising postoperative pulmonary complications (PPCs) after thoracic surgery is of utmost importance. A major factor contributing to PPCs is the driving pressure, which is determined by the ratio of tidal volume to lung compliance. Inhalation and intravenous administration of penehyclidine can improve lung compliance during intraoperative mechanical ventilation. Therefore, our study aimed to compare the efficacy of inhaled vs. intravenous penehyclidine during one-lung ventilation (OLV) in mitigating driving pressure and mechanical power among patients undergoing thoracic surgery.MethodsA double-blind, prospective, randomised study involving 176 patients scheduled for elective thoracic surgery was conducted. These patients were randomly divided into two groups, namely the penehyclidine inhalation group and the intravenous group before their surgery. Driving pressure was assessed at T1 (5 min after OLV), T2 (15 min after OLV), T3 (30 min after OLV), and T4 (45 min after OLV) in both groups. The primary outcome of this study was the composite measure of driving pressure during OLV. The area under the curve (AUC) of driving pressure from T1 to T4 was computed. Additionally, the secondary outcomes included mechanical power, lung compliance and the incidence of PPCs.ResultsAll 167 participants, 83 from the intravenous group and 84 from the inhalation group, completed the trial. The AUC of driving pressure for the intravenous group was 39.50 ± 9.42, while the inhalation group showed a value of 41.50 ± 8.03 (P = 0.138). The incidence of PPCs within 7 days after surgery was 27.7% in the intravenous group and 23.8% in the inhalation group (P = 0.564). No significant differences were observed in any of the other secondary outcomes between the two groups (all P > 0.05).ConclusionsOur study found that among patients undergoing thoracoscopic surgery, no significant differences were observed in the driving pressure and mechanical power during OLV between those who received an intravenous injection of penehyclidine and those who inhaled it. Moreover, no significant difference was observed in the incidence of PPCs between the two groups.

High-frequency chest wall oscillation multiple times daily can better reduce the loss of pulmonary surfactant and improve lung compliance in mechanically ventilated patients

BackgroundHigh-frequency chest wall oscillation (HFCWO) has been widely recognized for its airway secretion clearance effectiveness in critically ill ICU patients. ObjectivesThe purpose of this randomized controlled trial is to validate and compare the effects of different frequencies of HFCWO on oxygenation, lung compliance, and pulmonary surfactant proteins (SPs) in critically ill patients admitted to the intensive care unit (ICU). MethodsSixty patients with severe craniocerebral injury treated with a tracheostomy and mechanical ventilation were randomized into three groups (20 patients in each group): a single group (treated with 30 minutes of HFCWO once daily) and a double group (treated with 30 minutes of HFCWO twice daily), and a blank group (treated without HFCWO). Primary outcome measures included results on several specific proteins (SP-A, SP-B, SP-C, and SP-D) in serum and alveolar lavage fluid. Secondary outcome measures were lung static compliance test and oxygenation. ResultsPatients in both the single and double groups exhibited significant oxygenation and static compliance improvement. Similar results were observed in changes in SPs concentrations in the alveolar lavage fluid. However, a significant reduction of SPs levels was observed in the serum. In the group comparison analysis for the same variables between the single and double group, twice daily HFCWO treatments showed a significantly better result. ConclusionCompared with HFCWO once daily, HFCWO twice daily is advantageous in patients with tracheostomy and prolonged ventilation, which demonstrated significantly greater effectiveness in improving oxygenation and lung static compliance linked to the increase of and SPs contents in the airways as well as a reduction of SPs shift from airways to the blood.

The Effect of Prone Positioning After Lung Transplantation

BackgroundProne positioning has become a standard therapy in acute respiratory distress syndrome to improve oxygenation and decrease mortality. However, little is known about prone positioning in lung transplant recipients. This large, singe-center analysis investigated whether prone positioning improves gas exchange after lung transplantation. MethodsClinical data of 583 patients were analyzed. Prone position was considered in case of impaired gas exchange Pao2/fraction of oxygen in inhaled air (<250), signs of edema after lung transplantation, and/or evidence of reperfusion injury. Patients with hemodynamic instability or active bleeding were not proned. Impact of prone positioning (n = 165) on gas exchange, early outcome and survival were determined and compared with patients in supine positioning (n = 418). ResultsPatients in prone position were younger, more likely to have interstitial lung disease, and had a higher lung allocation score. Patients were proned for a median of 19 hours (interquartile range,15-26) hours). They had significantly lower Pao2/fraction of oxygen in inhaled air (227 ± 96 vs 303 ± 127 mm Hg, P = .004), and lower lung compliance (24.8 ± 9.1 mL/mbar vs 29.8 ± 9.7 mL/mbar, P < .001) immediately after lung transplantation. Both values significantly improved after prone positioning for 24 hours (Pao2/fraction of oxygen ratio: 331 ± 91 mm Hg; lung compliance: 31.7 ± 20.2 mL/mbar). Survival at 90 days was similar between the 2 groups (93% vs 96%, P = .105). ConclusionsProne positioning led to a significant improvement in lung compliance and oxygenation after lung transplantation. Prospective studies are needed to confirm the benefit of prone positioning in lung transplantation.

Multiple Dosing and Preactivation of Mesenchymal Stromal Cells Enhance Efficacy in Established Pneumonia Induced by Antimicrobial-Resistant Klebsiella pneumoniae in Rodents.

Antimicrobial-resistant (AMR) bacteria, such as Klebsiella species, are an increasingly common cause of hospital-acquired pneumonia, resulting in high mortality and morbidity. Harnessing the host immune response to AMR bacterial infection using mesenchymal stem cells (MSCs) is a promising approach to bypass bacterial AMR mechanisms. The administration of single doses of naïve MSCs to ARDS clinical trial patient cohorts has been shown to be safe, although efficacy is unclear. The study tested whether repeated MSC dosing and/or preactivation, would attenuate AMR Klebsiella pneumonia-induced established pneumonia. Rat models of established K. pneumoniae-induced pneumonia were randomised to receive intravenous naïve or cytomix-preactivated umbilical cord MSCs as a single dose at 24 h post pneumonia induction with or without a subsequent dose at 48 h. Physiological indices, bronchoalveolar lavage (BAL), and tissues were obtained at 72 h post pneumonia induction. A single dose of naïve MSCs was largely ineffective, whereas two doses of MSCs were effective in attenuating Klebsiella pneumosepsis, improving lung compliance and oxygenation, while reducing bacteria and injury in the lung. Cytomix-preactivated MSCs were superior to naïve MSCs. BAL neutrophil counts and activation were reduced, and apoptosis increased. MSC therapy reduced cytotoxic BAL T cells, and increased CD4+/CD8+ ratios. Systemically, granulocytes, classical monocytes, and the CD4+/CD8+ ratio were reduced, and nonclassical monocytes were increased. Repeated doses of MSCs-particularly preactivated MSCs-enhance their therapeutic potential in a clinically relevant model of established AMR K. pneumoniae-induced pneumosepsis.

Differential Effects of Cytokine Versus Hypoxic Preconditioning of Human Mesenchymal Stromal Cells in Pulmonary Sepsis Induced by Antimicrobial-Resistant Klebsiella pneumoniae.

Background: Pulmonary sepsis is a leading cause of hospital mortality, and sepses arising from antimicrobial-resistant (AMR) bacterial strains are particularly difficult to treat. Here we investigated the potential of mesenchymal stromal cells (MSCs) to combat established Klebsiella pneumoniae pneumosepsis and further evaluated MSC preconditioning and pre-activation methods. Methods: The potential for naïve and preconditioned MSCs to enhance wound healing, reduce inflammation, preserve metabolic activity, and enhance bacterial killing was assessed in vitro. Rats were subjected to intratracheal K. pneumoniae followed by the intravenous administration of MSCs. Physiological indices, blood, bronchoalveolar lavage (BAL), and tissues were obtained 72 h later. Results: In vitro assays confirmed that preconditioning enhances MSC function, accelerating pulmonary epithelial wound closure, reducing inflammation, attenuating cell death, and increasing bacterial killing. Cytomix-pre-activated MSCs are superior to naïve and hypoxia-exposed MSCs in attenuating Klebsiella pneumosepsis, improving lung compliance and oxygenation, reducing bacteria, and attenuating histologic injuries in lungs. BAL inflammatory cytokines were reduced, correlating with decreases in polymorphonuclear (PMN) cells. MSCs increased PMN apoptosis and the CD4:CD8 ratio in BAL. Systemically, granulocytes, classical monocytes, and the CD4:CD8 ratio were reduced, and nonclassical monocytes were increased. Conclusions: Preconditioning with cytokines, but not hypoxia, enhances the therapeutic potential of MSCs in clinically relevant models of K. pneumoniae-induced pneumosepsis.

Effects of airway pressure release ventilation on multi-organ injuries in severe acute respiratory distress syndrome pig models

BackgroundExtra-pulmonary multi-organ failure in patients with severe acute respiratory distress syndrome (ARDS) is a major cause of high mortality. Our purpose is to assess whether airway pressure release ventilation (APRV) causes more multi-organ damage than low tidal volume ventilation (LTV).MethodsTwenty one pigs were randomized into control group (n = 3), ARDS group (n = 3), LTV group (n = 8) and APRV group (n = 7). Severe ARDS model was induced by repeated bronchial saline lavages. Pigs were ventilated and monitored continuously for 48 h. Respiratory data, hemodynamic data, serum inflammatory cytokines were collected throughout the study. Histological injury and apoptosis were assessed by two pathologists.ResultsAfter severe ARDS modeling, pigs in ARDS, LTV and APRV groups experienced significant hypoxemia and reduced lung static compliance (Cstat). Oxygenation recovered progressively after 16 h mechanical ventilation (MV) in LTV and APRV group. The results of the repeated measures ANOVA showed no statistical difference in the PaO2/FiO2 ratio between the APRV and LTV groups (p = 0.54). The Cstat showed a considerable improvement in APRV group with statistical significance (p < 0.01), which was significantly higher than in the LTV group since 16 h (p = 0.04). Histological injury scores showed a significantly lower injury score in the middle and lower lobes of the right lung in the APRV group compared to LTV (pmiddle = 0.04, plower = 0.01), and no significant increase in injury scores for extra-pulmonary organs, including kidney (p = 0.10), small intestine (p = 1.0), liver (p = 0.14, p = 0.13) and heart (p = 0.20). There were no significant differences in serum inflammatory cytokines between the two groups.ConclusionIn conclusion, in the experimental pig models of severe ARDS induced by repetitive saline lavage, APRV improved lung compliance with reduced lung injury of middle and lower lobes, and did not demonstrate more extra-pulmonary organ injuries as compared with LTV.

Optimized ventilation strategy for surgery on patients with obesity from the perspective of lung protection: A network meta-analysis.

New ventilation modes have been proposed to support the perioperative treatment of patients with obesity, but there is a lack of consensus regarding the optimal strategy. Therefore, a network meta-analysis update of 13 ventilation strategies was conducted to determine the optimal mode of mechanical ventilation as a protective ventilation strategy decreases pulmonary atelectasis caused by inflammation. The following databases were searched: MEDLINE; Cochrane Library; Embase; CINAHL; Google Scholar; and Web of Science for randomized controlled trials of mechanical ventilation in patients with obesity published up to May 1, 2022. Volume-controlled ventilation with individualized positive end-expiratory pressure and a recruitment maneuver (VCV+PEEPind+RM) was found to be the most effective strategy for improving ratio of the arterial O2 partial pressure to the inspiratory O2 concentration (PaO2/FiO2), and superior to pressure-controlled ventilation (PCV), volume-controlled ventilation (VCV), volume-controlled ventilation with recruitment maneuver (VCV+RM), volume-controlled ventilation with low positive end-expiratory pressure (VCV+lowPEEP), volume-controlled ventilation with lower positive expiratory end pressure (PEEP) and recruitment maneuver (VCV+lowPEEP+RM), and the mean difference [MD], the 95% confidence intervals [CIs] and [quality of evidence] were: 162.19 [32.94, 291.45] [very low]; 180.74 [59.22, 302.27] [low]; 171.07 [40.60, 301.54] [very low]; 135.14 [36.10, 234.18] [low]; and 139.21 [27.08, 251.34] [very low]. Surface under the cumulative ranking curve (SUCRA) value showed VCV+PEEPind+RM was the best strategy for improving PaO2/FiO2 (SUCRA: 0.963). VCV with high positive PEEP and recruitment maneuver (VCV+highPEEP+RM) was more effective in decreasing postoperative pulmonary atelectasis than the VCV+lowPEEP+RM strategy. It was found that volume-controlled ventilation with high positive expiratory end pressure (VCV+highPEEP), risk ratio [RR] [95% CIs] and [quality of evidence], 0.56 [0.38, 0.81] [moderate], 0.56 [0.34, 0.92] [moderate]. SUCRA value ranked VCV+highPEEP+RM the best strategy for improving postoperative pulmonary atelectasis intervention (SUCRA: 0.933). It should be noted that the quality of evidence was in all cases very low or only moderate. This research suggests that VCV+PEEPind+RM is the optimal ventilation strategy for patients with obesity and is more effective in increasing PaO2/FiO2, improving lung compliance, and among the five ventilation strategies for postoperative atelectasis, VCV+highPEEP+RM had the greatest potential to reduce atelectasis caused by inflammation. https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021288941.

Roles of alpha-7 nicotinic acetylcholine receptors and spleen in the lung injury induced by a repeated saline lavage in rat

BackgroundThe study aimed to determine whether or notα7 nicotinic acetylcholine receptors (α7nAChR) induce anti-inflammatory effects directly in the lung or through the spleen pathway in a sterile model of lung injury by saline lavage.MethodsMale Sprague Dawley rats were divided into seven groups; Sham, splenectomy (SPX), saline lavage (LAV), LAV treated with α7nAChR agonist nicotine (LAV + NIC), and LAV treated with NIC and a selective α7nAChR antagonist MLA (LAV+MLA+NIC), LAV and splenectomy (LAV+SPX), and LAV+SPX treated with nicotine (LAV+SPX+NIC). Tracheostomy and catheterization of the femoral artery were performed under deep anesthesia. Animals were subjected to volume-controlled ventilation and lung injury by 10 repeated saline lavages. Splenectomy was achieved one week before the induction of lung injury. The recovery phase lasted for 3 h, and drugs were injected 1 h after the last lavage.ResultsMean arterial blood pressure (MBP), heart rate (HR), PaO2, PaO2/FiO2 ratio, and pH decreased, whereas, maximal inspiratory (MIP) and expiratory (MEP) pressures, and PaCO2 increased 1 h after the saline lavage. Nicotine corrected entirely all the above parameters in the LAV + NIC group. MLA or SPX prevented the effects of nicotine on the above parameters, except that MLA had no extra effect on MIP or MEP. In addition, nicotine improved lung compliance in the LAV + NIC and LAV + SPX + NIC groups, though it was inhibited by MLA in the LAV + MLA + NIC group. The increases of plasma and lung tissue malondialdehyde (MDA) in the LAV group were diminished by nicotine, whereas, MLA and SPX prevented these reductions. Besides, nicotine could reduce plasma MDA in the LAV + SPX + NIC group. Total BAL cell count, protein BAL/protein plasma ratio, and lung histological scores were attenuated by nicotine in the LAV + NIC group, whereas, MLA reversed the mentioned alterations in the LAV + MLA + NIC group. However, splenectomy could not stop the decreasing effect of nicotine on the total BAL cell in the LAV + SPX + NIC group.ConclusionsIn this study, we indicated that α7nAChR and spleen play roles in cholinergic anti-inflammatory pathways in saline lavage-induced lung injury. However, our results are in favor of at least some direct effects of α 7nAChR in the lung.

CARD17: Mitigation of the Inflammatory Response During Cardiopulmonary Bypass with Nitric Oxide Gas

Background: Cardiopulmonary bypass (CPB) is associated with an inflammatory response that increases morbidity and mortality. Previous studies demonstrate that the air-blood interface plays an important role in CPB induced inflammation. Nitric oxide (NO) is known to mitigate the inflammatory response. We sought to examine the effect of NO on the inflammatory response resulting from a large air-blood interface during CPB in a porcine model. Methods: Twenty-one healthy swine (40-50 kg) were placed on CPB for 2h using central cannulation through a right mini thoracotomy. Following placement of an aortic cross clamp, the myocardium was preserved with antegrade cold del Nido cardioplegia. Cardiac arrest was maintained for 45min. Group 1 (n=11), swine supported on CPB with a controlled 20% air blood shunt at 3-4:1 air:blood ratio. Group 2 (n=10), as group 1 with the addition of NO (500 ppm) mixed in the sweep gas of the oxygenator. Following weaning from CPB, animals were recovered and monitored for 2d. Survival, clinical outcomes, and blood assays for inflammatory markers were collected prior, during, and postCPB. Mann -Whitney U test and log rank test were performed to determine statistical significance in both groups. Results: There was no difference in our ability to wean from CPB between Groups. Two-day survival rate was superior in Group 2 (80% vs 54%, p=0.24). Immediately after CPB the time to extubation (95.3 ±32.6min vs 70.6 ±13.7min, p=0.07) and lung compliance (LC) (86.1% vs 75.3%, p=0.056) were better in Group 2. Troponin-I levels were higher in group 2 overall (21,7702+/-18,108 pg/ml vs 8491+/- 6,686 p=.055). Preliminary results (n=2 in each group) show elevated IL-6 (3.89 pg/ml vs 3.3pg/ml) in Group 1 and 2 respectively. At necropsy LC was 82.6% in group 1 vs 86.4% in group 2, p= 0.43. There were no differences in P-selectin or Cd11-b. Conclusions: Nitric oxide administration at high dose during CPB with a large air-blood interface attenuates components of the IL-6 pathway. NO was associated with decrease in overall mortality post bypass and improved lung compliance. Further studies are needed to characterize these findings and optimize NO dosing prior to clinical application.

ONE LUNG LUCY: PEDIATRIC ARDS IN A CHILD WITH LUNG AGENESIS

TYPE: Case Report TOPIC: Critical Care INTRODUCTION: Pediatric acute respiratory distress syndrome (PARDS) is a relatively common clinical problem in the PICU. However, ARDS in a pediatric patient with one lung is unique and not well defined. We present such a case and highlight challenges in management. CASE PRESENTATION: Our patient is a 14month old girl who presented to the ER in acute hypoxemic respiratory failure secondary to RSV bronchiolitis. Her past medical history is significant for left lung agenesis and supracardiac total anomalous pulmonary venous return (surgically repaired). She was admitted to the PICU and subsequently developed severe ARDS, with peak OI of 28. Single lung protective strategy was initially applied with the use of lower tidal volumes of 5-6 ml/kg and a PEEP of 6. Inhaled NO was employed and she was subsequently placed on tidal volumes of 8ml/kg and PEEP of 8 with subsequent improved lung compliance. She was successfully extubated after 2 weeks of MV. DISCUSSION: The Pediatric Acute Lung Injury Consensus Conference (PALICC) developed pediatric-specific definitions for ARDS and recommendations regarding treatment. Recommendations regarding management of patients with one lung who develop ARDS are lacking. One lung ventilation is a standard approach to facilitate surgical exposure for pulmonary and other thoracic surgeries, however it is not known whether ventilation strategies suggested by the anesthesia literature is applicable to PARDS. CONCLUSIONS: Our case presented challenges in providing adequate ventilation and oxygenation while minimizing further lung injury in a patient with one lung PARDS. Further study is needed to elucidate the optimum mechanical ventilation strategy. DISCLOSURE: Nothing to declare. KEYWORD: One Lung ARDS

Inhalation of Heliox as a Potential Treatment for the Acute Respiratory Distress Syndrome (ARDS) caused by Covid-19

Corona virus disease 2019 (COVID-19) is currently a global pandemic It presents as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) due to COVID-19 infection. Despite the widespread use of symptomatic, antiviral, and supportive treatment, the daily death toll from COVID-19 is still rising. The most common lethal complication is acute respiratory distress syndrome (ARDS). Mechanical ventilation is one of the necessary support methods of treating ARDS. Heliox (Heliumoxygen mixture) inhalation can reduce respiratory work of breathing, improve oxygenation, improve lung compliance, and effectively optimize the treatment of ARDS. Heliox also has potential anti-inflammatory, neuroprotective, and cardiac effects, and could reduce the inflammatory storm caused by SARS-CoV-2. This article reviews the properties of heliox, the therapeutic mechanism for ARDS, and the effects of heliox on inflammation, nerves, and the heart. Conclusion we suggests that heliox is a potential treatment for COVID-19.

External chest-wall compression in prolonged COVID-19 ARDS with low-compliance: a physiological study

BackgroundExternal chest-wall compression (ECC) is sometimes used in ARDS patients despite lack of evidence. It is currently unknown whether this practice has any clinical benefit in patients with COVID-19 ARDS (C-ARDS) characterized by a respiratory system compliance (Crs) < 35 mL/cmH2O.ObjectivesTo test if an ECC with a 5 L-bag in low-compliance C-ARDS can lead to a reduction in driving pressure (DP) and improve gas exchange, and to understand the underlying mechanisms.MethodsEleven patients with low-compliance C-ARDS were enrolled and underwent 4 steps: baseline, ECC for 60 min, ECC discontinuation and PEEP reduction. Respiratory mechanics, gas exchange, hemodynamics and electrical impedance tomography were recorded. Four pigs with acute ARDS were studied with ECC to understand the effect of ECC on pleural pressure gradient using pleural pressure transducers in both non-dependent and dependent lung regions.ResultsFive minutes of ECC reduced DP from baseline 14.2 ± 1.3 to 12.3 ± 1.3 cmH2O (P < 0.001), explained by an improved lung compliance. Changes in DP by ECC were strongly correlated with changes in DP obtained with PEEP reduction (R2 = 0.82, P < 0.001). The initial benefit of ECC decreased over time (DP = 13.3 ± 1.5 cmH2O at 60 min, P = 0.03 vs. baseline). Gas exchange and hemodynamics were unaffected by ECC. In four pigs with lung injury, ECC led to a decrease in the pleural pressure gradient at end-inspiration [2.2 (1.1–3) vs. 3.0 (2.2–4.1) cmH2O, P = 0.035].ConclusionsIn C-ARDS patients with Crs < 35 mL/cmH2O, ECC acutely reduces DP. ECC does not improve oxygenation but it can be used as a simple tool to detect hyperinflation as it improves Crs and reduces Ppl gradient. ECC benefits seem to partially fade over time. ECC produces similar changes compared to PEEP reduction.

Physiological effect of prone positioning in mechanically ventilated SARS-CoV-2- infected patients with severe ARDS: An observational study.

Background and Aims:Mechanical ventilation in prone position was associated with a reduction in mortality and increase in arterial oxygenation in acute respiratory distress syndrome (ARDS) patients. However, physiological effects of prone position in COVID ARDS patients are unknown.Material and Methods:In this prospective observational study, data of n = 47 consecutive real time RT- PCR confirmed SARS-CoV-2-infected patients with severe ARDS were included. Respiratory mechanics and oxygenation data of recruited patients were collected before and after prone position.Results:Median (Interquartile range, IQR) age of the recruited patients was 60 (50–67) years and median (IQR) PaO2/FiO2 ratio of 61.2 (54–80) mm Hg with application of median (IQR) positive end expiratory pressure (PEEP) of 12 (10–14) cm H2O before initiation of prone position. Out of those patients, 36 (77%) were prone responders at 16 hours after prone session, evident by increase of PaO2 by at least 20 mm Hg or by 20% as compared to baseline, and 73% patients were sustained responders (after returning to supine position). Plateau airway pressure (p < 0.0001), peak airway pressure (p < 0.0001), and driving pressure (p < 0.0001) were significantly reduced in prone position, and static compliance (p = 0.001), PaO2/FiO2 ratio (p < 0.0001), PaO2 (p = 0.0002), and SpO2 (p = 0.0004) were increased at 4 hours and 16 hours since prone position and also after returning to supine position.Conclusion:In SARS-CoV-2-infected patients, mechanical ventilation in prone position is associated with improvement in lung compliance and oxygenation in almost three-fourth of the patients and persisted in supine position in more than 70% of the patients.

Association of Antenatal Terbutaline and Respiratory Support Requirements in Preterm Neonates.

Before the advent of antenatal steroids, early non-invasive respiratory support (NIV), and intratracheal surfactant, antenatal terbutaline was also used to improve lung compliance and reduce the incidence of respiratory distress syndrome (RDS). The objective of this paper was to study the association between antenatal terbutaline and endotracheal intubation (ET) within the first 24 hours of life, RDS, bronchopulmonary dysplasia (BPD), and intraventricular hemorrhage (IVH) in infants with the gestational age (GA) of <32 weeks, and to study the association between antenatal terbutaline, and ET or NIV within the first 24 hours of life, and RDS in infants with the GA of 32 to 36 weeks. This was a retrospective medical record review of preterm infants delivered at a single tertiary care center from October 2016 to December 2020. Multivariable logistic regression was used to explore the association between antenatal terbutaline and neonatal respiratory support. 1,794 infants were included, 234 (13.0%) had the GA of <32 weeks and 1,560 (86.9%) had the GA of 32 to 36 weeks. Antenatal terbutaline, corticosteroid, or both agents were administered in 561 (31.3%), 1,461 (81.4%), and 555 (30.9%), respectively. Antenatal terbutaline was significantly associated with a reduction in ET (adjusted odds ratio [aOR] = 0.40, 95% confident interval [CI] 0.19-0.82, p = 0.012) in infants with the GA of <32 weeks, but not in infants with the GA of 32-36 weeks. Antenatal terbutaline was not associated with RDS or BPD but was significantly associated with a reduction in grade III-IV IVH (aOR 0.11, CI 0.01-0.98; p = 0.048), in infants with the GA of <32 weeks. In a state-of-the-art neonatal care setting, antenatal terbutaline was associated with a reduction in ET during the first 24 hours in infants with the GA of <32 weeks. The use of antenatal terbutaline to improve acute neonatal respiratory outcomes merits reconsideration. · The neonatal respiratory benefits of antenatal terbutaline in the era of antenatal corticosteroids were uncertain.. · Terbutaline is associated with a reduction in endotracheal intubation in a modern care setting.. · The role of terbutaline, and potentially other betamimetics, to improve neonatal respiratory outcomes merits reconsideration..

Hexarelin modulates lung mechanics, inflammation, and fibrosis in acute lung injury.

Introduction: Acute respiratory distress syndrome (ARDS) is an acute form of diffuse lung injury characterized by (i) an intense inflammatory response, (ii) increased pulmonary vascular permeability, and (iii) the loss of respiratory pulmonary tissue. In this article we explore the therapeutic potential of hexarelin, a synthetic hexapeptide growth hormone secretagogue (GHS), in an experimental model of ARDS. Hexarelin has anti-inflammatory properties and demonstrates cardiovascular-protective activities including the inhibition of cardiomyocyte apoptosis and cardiac fibrosis, both of which may involve the angiotensin-converting enzyme (ACE) system. Methods: In our experimental model, ARDS was induced by the instillation of 100 mM HCl into the right bronchus; these mice were treated with hexarelin (320 μg/kg, ip) before (Pre) or after (Post) HCl challenge, or with vehicle. Respiratory system compliance, blood gas analysis, and differential cell counts in a selective bronchoalveolar lavage (BAL) were determined 6 or 24 hours after HCl instillation. In an extended study, mice were observed for a subsequent 14 days in order to assess lung fibrosis. Results: Hexarelin induced a significant improvement in lung compliance and a reduction of the number of total immune cells in BAL 24 hours after HCl instillation, accompanied with a lower recruitment of neutrophils compared with the vehicle group. At day 14, hexarelin-treated mice presented with less pulmonary collagen deposition compared with vehicle-treated controls. Conclusions: Our data suggest that hexarelin can inhibit the early phase of the inflammatory response in a murine model of HCl-induced ARDS, thereby blunting lung remodeling processes and fibrotic development.