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Background: Improvements in oxygenation and lung mechanics with prone position (PP) in patients with acute respiratory distress syndrome (ARDS) are inconstant. The objectives of the study were (i) to identify baseline variables, including the recruitment-to-inflation ratio (R/I), associated with a positive response to PP in terms of oxygenation (improvement of the ratio of arterial oxygen partial pressure over the inspired oxygen fraction (PaO2/FiO2) ≥ 20 mmHg) and lung mechanics; (ii) to evaluate whether the response to the previous PP session is associated with the response to the next session. Methods: In this prospective, observational, single-center study in patients who underwent PP for ARDS due to COVID-19, respiratory variables were assessed just before PP and at the end of the session. Respiratory variables included mechanical ventilation settings and respiratory mechanics variables, including R/I, an estimate of the potential for lung recruitment compared to lung overinflation. Results: In 50 patients, 201 PP sessions lasting 19 ± 3 h were evaluated. Neuromuscular blockades were used in 116 (58%) sessions. The PaO2/FiO2 ratio increased from 109 ± 31 mmHg to 165 ± 65 mmHg, with an increase ≥ 20 mmHg in 142 (71%) sessions. In a mixed effect logistic regression, only pre-PP PaO2/FiO2 (OR 1.12 (95% CI [1.01–1.24])/every decrease of 10 mmHg, p = 0.034) in a first model and improvement in oxygenation at the previous PP session (OR 3.69 (95% CI [1.27–10.72]), p = 0.017) in a second model were associated with an improvement in oxygenation with PP. The R/I ratio (n = 156 sessions) was 0.53 (0.30–0.76), separating lower- and higher-recruiters. Whereas PaO2/FiO2 improved to the same level in both subgroups, driving pressure and respiratory system compliance improved only in higher-recruiters (from 14 ± 4 to 12 ± 4 cmH2O, p = 0.027, and from 34 ± 11 to 38 ± 13 mL/cmH2O, respectively, p = 0.014). Conclusions: A lower PaO2/FiO2 at baseline and a positive O2-response at the previous PP session are associated with a PP-induced improvement in oxygenation. In higher-recruiters, lung mechanics improved along with oxygenation. Benefits of PP could thus be greater in these patients. [ABSTRACT FROM AUTHOR]

The aim of this study is to study cardio-respiratory effects of nasal high-frequency oscillatory ventilation (NHFOV) vs. NCPAP as an initial mode of ventilation in moderate-late-preterm infants. A randomized controlled trial was conducted in NICU of Alexandria University Maternity Hospital (AUMH). One-hundred late-moderate-preterm infants were randomly assigned to either NHFOV-group (n = 50) or NCPAP-group (n = 50). For both groups, functional echocardiography was performed in the first 24 h to detect hemodynamic changes and respiratory outcome was monitored throughout the hospital stay. The main outcomes were hemodynamic measurements and myocardial function using functional echocardiography of those infants along with the respiratory outcome and complications. Kaplan–Meier survival plot was used representing time course of NCPAP and NHFOV failure. Left ventricular output values were not significantly different in both groups with median 202 ml/kg /min and IQR (176–275) in NCPAP-group and 226 ml/kg/min with IQR (181–286) in NHFOV group. Nevertheless, ejection fraction and fractional shortening were significantly higher in NHFOV-group with P 0.001. The time to weaning, the time to reach 30%-FIO2, the need for invasive ventilation, oxygen support duration, and maximal-FIO2 were significantly more in NCAPAP group. Conclusion: NHFOV is an effective and promising tool of non-invasive-ventilation which can be used as a primary modality of respiratory support in preterm infants with variable forms of respiratory distress syndrome without causing detrimental effect on hemodynamics or significant respiratory complications. Trial registration: NCT05706428 (registered on January 21, 2023). What is Known: • NHFOV might be beneficial as a secondary mode of ventilation and might have an impact on hemodynamics. What is New: • NHFOV can be used as an initial mode of ventilation with CDP beyond the reported pressure limits of CPAP without causing neither CO2 retention nor adverse hemodynamic consequences. [ABSTRACT FROM AUTHOR]

Background: Patients with obesity are at increased risk of postoperative pulmonary complications. CPAP has been used successfully to prevent and treat acute respiratory failure, but in many clinical scenarios, high-flow nasal cannula (HFNC) therapy is emerging as a possible alternative. We aimed to compare HFNC and CPAP in a sequential study measuring their effects on gas exchange, lung volumes, and gas distribution within the lungs measured through electrical impedance tomography (EIT). Methods: We enrolled 15 subjects undergoing laparoscopic bariatric surgery. Postoperatively they underwent the following oxygen therapy protocol (10 min/step): baseline air-entrainment mask, HFNC at increasing (40, 60, 80, and 100 L/min) and decreasing flows (80, 60, and 40 L/min), washout air-entrainment mask and CPAP (10 cm H2O). Primary outcome was the change in end-expiratory lung impedance (ΔEELI) measured by EIT data processing. Secondary outcomes were changes of global inhomogeneity (GI) index and tidal impedance variation (TIV) measured by EIT, arterial oxygenation, carbon dioxide content, pH, respiratory frequency, and subject's comfort. Results: Thirteen subjects completed the study. Compared to baseline, ΔEELI was higher during 10 cm H2O CPAP (P = .001) and HFNC 100 L/min (P = .02), as well as during decreasing flows HFNC 80, 60, and 40 L/min (P = .008, .004, and .02, respectively). GI index was lower during HFNC 100 compared to HFNC 60increasing (P = .044), HFNC 60decreasing (P = .02) HFNC 40decreasing (P = .01), and during 10 cm H2O CPAP compared to washout period (P = .01) and HFNC 40decreasing (P = .03). TIV was higher during 10 cm H2O CPAP compared to baseline (P = .008). Compared to baseline, breathing frequency was lower at HFNC 60increasing, HFNC 100, and HFNC 80decreasing (P = .01, .02, and .03, respectively). No differences were detected regarding arterial oxygenation, carbon dioxide content, pH, and subject's comfort. Conclusions: HFNC at a flow of 100 L/min induced postoperative pulmonary recruitment in bariatric subjects, with no significant differences compared to 10 cm H2O CPAP in terms of lung recruitment and ventilation distribution. [ABSTRACT FROM AUTHOR]

Abstract Background Surfactant is a well-established therapy for preterm neonates affected by respiratory distress syndrome (RDS). The goals of different methods of surfactant administration are to reduce the duration of mechanical ventilation and the severity of bronchopulmonary dysplasia (BPD); however, the optimal administration method remains unknown. This study compares the effectiveness of the INtubate-RECruit-SURfactant-Extubate (IN-REC-SUR-E) technique with the less-invasive surfactant administration (LISA) technique, in increasing BPD-free survival of preterm infants. This is an international unblinded multicenter randomized controlled study in which preterm infants will be randomized into two groups to receive IN-REC-SUR-E or LISA surfactant administration. Methods In this study, 382 infants born at 24+0–27+6 weeks’ gestation, not intubated in the delivery room and failing nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure ventilation (NIPPV) during the first 24 h of life, will be randomized 1:1 to receive IN-REC-SUR-E or LISA surfactant administration. The primary outcome is a composite outcome of death or BPD at 36 weeks’ postmenstrual age. The secondary outcomes are BPD at 36 weeks’ postmenstrual age; death; pulse oximetry/fraction of inspired oxygen; severe intraventricular hemorrhage; pneumothorax; duration of respiratory support and oxygen therapy; pulmonary hemorrhage; patent ductus arteriosus undergoing treatment; percentage of infants receiving more doses of surfactant; periventricular leukomalacia, severe retinopathy of prematurity, necrotizing enterocolitis, sepsis; total in-hospital stay; systemic postnatal steroids; neurodevelopmental outcomes; and respiratory function testing at 24 months of age. Randomization will be centrally provided using both stratification and permuted blocks with random block sizes and block order. Stratification factors will include center and gestational age (24+0 to 25+6 weeks or 26+0 to 27+6 weeks). Analyses will be conducted in both intention-to-treat and per-protocol populations, utilizing a log-binomial regression model that corrects for stratification factors to estimate the adjusted relative risk (RR). Discussion This trial is designed to provide robust data on the best method of surfactant administration in spontaneously breathing preterm infants born at 24+0–27+6 weeks’ gestation affected by RDS and failing nCPAP or NIPPV during the first 24 h of life, comparing IN-REC-SUR-E to LISA technique, in increasing BPD-free survival at 36 weeks’ postmenstrual age of life. Trial registration ClinicalTrials.gov NCT05711966. Registered on February 3, 2023.

Abstract Background The recruitment-to-inflation ratio (R/I) has been recently proposed to bedside assess response to PEEP. The impact of PEEP on ventilator-induced lung injury depends on the extent of dynamic strain reduction. We hypothesized that R/I may reflect the potential for lung recruitment (i.e. recruitability) and, consequently, estimate the impact of PEEP on dynamic lung strain, both assessed through computed tomography scan. Methods Fourteen lung-damaged pigs (lipopolysaccharide infusion) underwent ventilation at low (5 cmH2O) and high PEEP (i.e., PEEP generating a plateau pressure of 28–30 cmH2O). R/I was measured through a one-breath derecruitment maneuver from high to low PEEP. PEEP-induced changes in dynamic lung strain, difference in nonaerated lung tissue weight (tissue recruitment) and amount of gas entering previously nonaerated lung units (gas recruitment) were assessed through computed tomography scan. Tissue and gas recruitment were normalized to the weight and gas volume of previously ventilated lung areas at low PEEP (normalized-tissue recruitment and normalized-gas recruitment, respectively). Results Between high (median [interquartile range] 20 cmH2O [18–21]) and low PEEP, median R/I was 1.08 [0.88–1.82], indicating high lung recruitability. Compared to low PEEP, tissue and gas recruitment at high PEEP were 246 g [182–288] and 385 ml [318–668], respectively. R/I was linearly related to normalized-gas recruitment (r = 0.90; [95% CI 0.71 to 0.97) and normalized-tissue recruitment (r = 0.69; [95% CI 0.25 to 0.89]). Dynamic lung strain was 0.37 [0.29–0.44] at high PEEP and 0.59 [0.46–0.80] at low PEEP (p

Background: The recruitment-to-inflation ratio (R/I) has been recently proposed to bedside assess response to PEEP. The impact of PEEP on ventilator-induced lung injury depends on the extent of dynamic strain reduction. We hypothesized that R/I may reflect the potential for lung recruitment (i.e. recruitability) and, consequently, estimate the impact of PEEP on dynamic lung strain, both assessed through computed tomography scan. Methods: Fourteen lung-damaged pigs (lipopolysaccharide infusion) underwent ventilation at low (5 cmH2O) and high PEEP (i.e., PEEP generating a plateau pressure of 28–30 cmH2O). R/I was measured through a one-breath derecruitment maneuver from high to low PEEP. PEEP-induced changes in dynamic lung strain, difference in nonaerated lung tissue weight (tissue recruitment) and amount of gas entering previously nonaerated lung units (gas recruitment) were assessed through computed tomography scan. Tissue and gas recruitment were normalized to the weight and gas volume of previously ventilated lung areas at low PEEP (normalized-tissue recruitment and normalized-gas recruitment, respectively). Results: Between high (median [interquartile range] 20 cmH2O [18–21]) and low PEEP, median R/I was 1.08 [0.88–1.82], indicating high lung recruitability. Compared to low PEEP, tissue and gas recruitment at high PEEP were 246 g [182–288] and 385 ml [318–668], respectively. R/I was linearly related to normalized-gas recruitment (r = 0.90; [95% CI 0.71 to 0.97) and normalized-tissue recruitment (r = 0.69; [95% CI 0.25 to 0.89]). Dynamic lung strain was 0.37 [0.29–0.44] at high PEEP and 0.59 [0.46–0.80] at low PEEP (p < 0.001). R/I was significantly related to PEEP-induced reduction in dynamic (r = − 0.93; [95% CI − 0.78 to − 0.98]) and global lung strain (r = − 0.57; [95% CI − 0.05 to − 0.84]). No correlation was found between R/I and and PEEP-induced changes in static lung strain (r = 0.34; [95% CI − 0.23 to 0.74]). Conclusions: In a highly recruitable ARDS model, R/I reflects the potential for lung recruitment and well estimates the extent of PEEP-induced reduction in dynamic lung strain. [ABSTRACT FROM AUTHOR]

The article presents a study which examined whether there is a stabilization of the dependent dorsal lung aeration day after day in supine position (SP) after prone position (PP) between first PP and last PP sessions using electrical impedance tomography (EIT). Topics include dependent-lung recruitment with PP, dependent dorsal-lung de-recruitment after PP, and finding on the correlation between daily percentage of dorsal lung-dependent area collapse in SP and oxygenation response during PP.

ABSTRACTBackground The concept of lung protective ventilation (LPV) during general anesthesia (GA) aims at minimizing lung injury and postoperative pulmonary complications (POPCs). Recruitment maneuver (RM) as a part of LPV may improve lung mechanics and oxygenation, but despite extensive research, definitive guidelines for the applications of intraoperative RMs have not been established yet.Methods This study was a prospective, single-blinded, randomized clinical trial. Sixty-six subjects undergoing non-laparoscopic upper abdominal surgeries under GA were randomly assigned into two equal groups. Control group (C) received tidal volume of 8 ml/kg predicted body weight (PBW) and positive end expiratory pressure (PEEP) of 5 cmH2O without RM. Recruitment group (R) received tidal volume of 8 ml/kg PBW with stepwise RMs and individualized PEEP titration after each RM. Compliance, plateau pressure, driving pressure, SpO2 and hemodynamics were monitored at each step of RM. POPCs, length of hospital stay and mortality were recorded postoperatively.Results There was a significant reduction in POPCs in (R) group than in (C) group (P = 0.03). Also, there was a significant increase in compliance before extubation in (R) group (P = 0.001). However, no significant difference was noted between both groups as regards mortality rate and length of hospital stay.Conclusion Individualized stepwise lung RM significantly decreases the incidence of POPCs when added to LPV in patients undergoing non-laparoscopic upper abdominal surgeries under GA.

Background: The concept of lung protective ventilation (LPV) during general anesthesia (GA) aims at minimizing lung injury and postoperative pulmonary complications (POPCs). Recruitment maneuver (RM) as a part of LPV may improve lung mechanics and oxygenation, but despite extensive research, definitive guidelines for the applications of intraoperative RMs have not been established yet. Methods: This study was a prospective, single-blinded, randomized clinical trial. Sixty-six subjects undergoing non-laparoscopic upper abdominal surgeries under GA were randomly assigned into two equal groups. Control group (C) received tidal volume of 8 ml/kg predicted body weight (PBW) and positive end expiratory pressure (PEEP) of 5 cmH2O without RM. Recruitment group (R) received tidal volume of 8 ml/kg PBW with stepwise RMs and individualized PEEP titration after each RM. Compliance, plateau pressure, driving pressure, SpO2 and hemodynamics were monitored at each step of RM. POPCs, length of hospital stay and mortality were recorded postoperatively. Results: There was a significant reduction in POPCs in (R) group than in (C) group (P = 0.03). Also, there was a significant increase in compliance before extubation in (R) group (P = 0.001). However, no significant difference was noted between both groups as regards mortality rate and length of hospital stay. Conclusion: Individualized stepwise lung RM significantly decreases the incidence of POPCs when added to LPV in patients undergoing non-laparoscopic upper abdominal surgeries under GA. [ABSTRACT FROM AUTHOR]

Patients with acute respiratory distress syndrome (ARDS) have few treatment options other than supportive mechanical ventilation. The mortality associated with ARDS remains unacceptably high, and mechanical ventilation itself has the potential to increase mortality further by unintended ventilator-induced lung injury (VILI). Thus, there is motivation to improve management of ventilation in patients with ARDS. The immediate goal of mechanical ventilation in ARDS should be to prevent atelectrauma resulting from repetitive alveolar collapse and reopening. However, a long-term goal should be to re-open collapsed and edematous regions of the lung and reduce regions of high mechanical stress that lead to regional volutrauma. In this paper, we consider the proposed strategy used by the full-term newborn to open the fluid-filled lung during the initial breaths of life, by ratcheting tissues opened over a series of initial breaths with brief expirations. The newborn's cry after birth shares key similarities with the Airway Pressure Release Ventilation (APRV) modality, in which the expiratory duration is sufficiently short to minimize end-expiratory derecruitment. Using a simple computational model of the injured lung, we demonstrate that APRV can slowly open even the most recalcitrant alveoli with extended periods of high inspiratory pressure, while reducing alveolar re-collapse with brief expirations. These processes together comprise a ratchet mechanism by which the lung is progressively recruited, similar to the manner in which the newborn lung is aerated during a series of cries, albeit over longer time scales. [ABSTRACT FROM AUTHOR]

Background Lung recruitment maneuvers (LRMs) are a strategy to gradually increase mean positive airway pressure (MAP) to expand the alveoli, leading to decreased pulmonary vascular resistance and increased cardiac output (CO). However, the hemodynamic impact of LRM using assist control volume guarantee (AC-VG) ventilator mode done in preterm infants born at 24 to 32 weeks’ gestation, especially in the first 72 hours of life, remains unknown. Objective To determine the effect of LRM on right- and left cardiac ventricular output (RVO and LVO), ductus arteriosus (DA) diameter and its pulmonary hypertension (PH) flow pattern, as well as superior mesenteric artery (SMA) flow. Method This randomized, controlled, single-blinded clinical trial was performed in 24-32-week preterm neonates with birth weights of >600 grams. Subjects were allocated by block randomization to the LRM and control groups, each containing 55 subjects. We measured RVO, LVO, DA diameter, PH flow pattern, and SMA resistive index (RI) at 1 and 72 hours after mechanical ventilation was applied. We analyzed for hemodynamic differences between the two groups. Results During the initial 72 hours of mechanical ventilation, there were no significant differences between the control vs. LRM groups in mean changes of LVO [41.40 (SD 91.21) vs. 15.65 (SD 82.39) mL/kg/min, respectively; (P=0.138)] or mean changes of RVO [65.56 (SD 151.20) vs. 70.59 (SD 133.95) mL/kg/min, respectively; (P=0.859)]. Median DA diameter reduction was -0.08 [interquartile range (IQR) -0.55; 0.14] mm in the control group and -0.10 (IQR -0.17 to -0.01) mm in the LRM group (P=0.481). Median SMA resistive index was 0.02 (IQR -0.16 to 0.24) vs. 0.01(IQR -0.20 to 0.10) in the control vs. LRM group, respectively. There was no difference in proportion of pulmonary hypertension flow pattern at 72 hours (25.4% vs. 20% in the control vs. LRM group, respectively) (P=0.495). Conclusion When preterm infants of 24-32 weeks gestational age are placed on mechanical ventilation, LRM gives neither additional hemodynamic benefit nor harm compared to standard ventilator settings.

Patients with acute respiratory distress syndrome (ARDS) have few treatment options other than supportive mechanical ventilation. The mortality associated with ARDS remains unacceptably high, and mechanical ventilation itself has the potential to increase mortality further by unintended ventilator-induced lung injury (VILI). Thus, there is motivation to improve management of ventilation in patients with ARDS. The immediate goal of mechanical ventilation in ARDS should be to prevent atelectrauma resulting from repetitive alveolar collapse and reopening. However, a long-term goal should be to re-open collapsed and edematous regions of the lung and reduce regions of high mechanical stress that lead to regional volutrauma. In this paper, we consider the proposed strategy used by the full-term newborn to open the fluid-filled lung during the initial breaths of life, by ratcheting tissues opened over a series of initial breaths with brief expirations. The newborn’s cry after birth shares key similarities with the Airway Pressure Release Ventilation (APRV) modality, in which the expiratory duration is sufficiently short to minimize end-expiratory derecruitment. Using a simple computational model of the injured lung, we demonstrate that APRV can slowly open even the most recalcitrant alveoli with extended periods of high inspiratory pressure, while reducing alveolar re-collapse with brief expirations. These processes together comprise a ratchet mechanism by which the lung is progressively recruited, similar to the manner in which the newborn lung is aerated during a series of cries, albeit over longer time scales.

Mechanical ventilation has long been recognized as the most vital therapy for patients with ARDS. Compared with lung-protective ventilation, debates that involve the open lung strategy, which consists primarily of the lung recruitment maneuver and higher PEEP, have never been resolved. In terms of the beneficial and detrimental effects of this aggressive maneuver, appraisal of lung recruitment is essential for intensivists to make clinical decisions. This review aimed to clarify how to assess the potential for lung recruitment based on respiratory mechanics when using the pressure-volume curve or loop method and end-expiratory lung volume--static compliance of the respiratory system method. However, their limitations related to excessive generalization, accuracy, and identification of cutoff values cannot be omitted. Finally, future studies are warranted to combine these classic methods with newly invented techniques to achieve safer and more effective lung recruitment. [ABSTRACT FROM AUTHOR]

Abstract Prone positioning is an evidence-based treatment for patients with moderate-to-severe acute respiratory distress syndrome. Lung recruitment has been proposed as one of the mechanisms by which prone positioning reduces mortality in this group of patients. Recruitment-to-inflation ratio (R/I) is a method to measure potential for lung recruitment induced by a change in positive end-expiratory pressure (PEEP) on the ventilator. The association between R/I and potential for lung recruitment in supine and prone position has not been studied with computed tomography (CT) scan imaging. In this secondary analysis, we sought to investigate the correlation between R/I measured in supine and prone position with CT and the potential for lung recruitment as measured by CT scan. Among 23 patients, the median R/I did not significantly change from supine (1.9 IQR 1.6–2.6) to prone position (1.7 IQR 1.3–2.8) (paired t test p = 0.051) but the individual changes correlated with the different response to PEEP. In supine and in prone position, R/I significantly correlated with the proportion of lung tissue recruitment induced by the change of PEEP. Lung tissue recruitment induced by a change of PEEP from 5 to 15 cmH2O was 16% (IQR 11–24%) in supine and 14.3% (IQR 8.4–22.6%) in prone position, as measured by CT scan analysis (paired t test p = 0.56). In this analysis, PEEP-induced recruitability as measured by R/I correlated with PEEP-induced lung recruitment as measured by CT scan, and could help to readjust PEEP in prone position.

Lung recruitment maneuvers following one-lung ventilation (OLV) increase the risk for the development of acute lung injury. The application of continuous negative extrathoracic pressure (CNEP) is gaining interest both in intubated and non-intubated patients. However, there is still a lack of knowledge on the ability of CNEP support to recruit whole lung atelectasis following OLV. We investigated the effects of CNEP following OLV on lung expansion, gas exchange, and hemodynamics. Ten pigs were anesthetized and mechanically ventilated with pressure-regulated volume control mode (PRVC; FiO2: 0.5, Fr: 30–35/min, VT: 7 mL/kg, PEEP: 5 cmH2O) for 1 hour, then baseline (BL) data for gas exchange (arterial partial pressure of oxygen, PaO2; and carbon dioxide, PaCO2), ventilation and hemodynamical parameters and lung aeration by electrical impedance tomography were recorded. Subsequently, an endobronchial blocker was inserted, and OLV was applied with a reduced VT of 5 mL/kg. Following a new set of measurements after 1 h of OLV, two-lung ventilation was re-established, combining PRVC (VT: 7 mL/kg) and CNEP (−15 cmH2O) without any hyperinflation maneuver and data collection was then repeated at 5 min and 1 h. Compared to OLV, significant increases in PaO2 (154.1 ± 13.3 vs. 173.8 ± 22.1) and decreases in PaCO2 (52.6 ± 11.7 vs. 40.3 ± 4.5 mmHg, p < 0.05 for both) were observed 5 minutes following initiation of CNEP, and these benefits in gas exchange remained after an hour of CNEP. Gradual improvements in lung aeration in the non-collapsed lung were also detected by electrical impedance tomography (p < 0.05) after 5 and 60 min of CNEP. Hemodynamics and ventilation parameters remained stable under CNEP. Application of CNEP in the presence of whole lung atelectasis proved to be efficient in improving gas exchange via recruiting the lung without excessive airway pressures. These benefits of combined CNEP and positive pressure ventilation may have particular value in relieving atelectasis in the postoperative period of surgical procedures requiring OLV. [ABSTRACT FROM AUTHOR]

Background In the case of critically sick patients, acute respiratory distress syndrome (ARDS) may be life-threatening and necessitates the need for ICU admission. Continuous monitoring is required for mechanical ventilation and recruitment movements as necessary. In this research, the goal is to investigate the use of ultrasonography in the evaluation of positive end exhalatory pressure-induced lung recruitment in ARDS patients. Patients and methods A total of 25 ARDS patients were included in this research, which was done in the hospital’s respiratory care unit. All of the patients were seen by a doctor, had a chest radiograph, and had laboratory tests. Mechanical ventilation was used in the care of all patients. Using positive end-expiratory pressure (PEEP) values of 5 and 15, we measured pressure–volume (PV) and lung ultrasound tracings. The PV curve approach was used to assess PEEP-induced lung recruitment. Between PEEP 5 and PEEP 15, there was an extremely strong positive connection between reaeration score and the change in lung volume (r=0.737, P=0.001). Results Between PEEP 5 and PEEP 15, there was a substantial (r=0.577, P=0.003) positive association between the reaeration score and the decrease in PaO2. There was a substantial negative association between reaeration score and mortality (rpb=-0.842, P=0.001), in which mortality reduces as the score increases. Conclusion For quantitative evaluation of PEEP-induced lung recruitment, bedside lung ultrasound is equal to the PV curve approach. In patients with ARDS, PEEP-induced lung recruitment may be assessed using ultrasonography.

Background One lung ventilation for lung resection surgery may affect oxygenation, impair lung mechanics and increase the incidence of acute lung injury. Lung recruitment maneuver may improve these conditions. Settings and Design This study was a prospective randomized controlled single blinded clinical trial. Methods Forty patients scheduled for elective lung resection surgeries using one lung ventilation under general anaesthesia were randomly allocated into two groups. Control (C) group was subjected to conventional mechanical ventilation of tidal volume of 8 ml/kg and 5 ml/kg for total lung ventilation (TLV) and one lung ventilation (OLV), respectively, and PEEP of 5 cmH2O and (LR) group which was subjected to stepwise lung recruitment twice: The first lung recruitment (LR1) was performed after (OLV) to the dependent lung, while the second lung recruitment (LR2) was performed after resuming (TLV). Arterial blood gases, lung mechanics and serum tumor necrosis factor alpha were recorded at multiple time points during the study. The proposal and raw data were registered on PACTR as PACTR202001518687696. Results There was a significant decrease in PaO2/FIO2 during OLV baseline in comparison to TLV baseline (P = < 0.001*) in both groups. While, in LR group, there was a significant increase in PaO2/FIO2 and dynamic compliance during OLV-20 min after recruitment (P =

Prone positioning is an evidence-based treatment for patients with moderate-to-severe acute respiratory distress syndrome. Lung recruitment has been proposed as one of the mechanisms by which prone positioning reduces mortality in this group of patients. Recruitment-to-inflation ratio (R/I) is a method to measure potential for lung recruitment induced by a change in positive end-expiratory pressure (PEEP) on the ventilator. The association between R/I and potential for lung recruitment in supine and prone position has not been studied with computed tomography (CT) scan imaging. In this secondary analysis, we sought to investigate the correlation between R/I measured in supine and prone position with CT and the potential for lung recruitment as measured by CT scan. Among 23 patients, the median R/I did not significantly change from supine (1.9 IQR 1.6–2.6) to prone position (1.7 IQR 1.3–2.8) (paired t test p = 0.051) but the individual changes correlated with the different response to PEEP. In supine and in prone position, R/I significantly correlated with the proportion of lung tissue recruitment induced by the change of PEEP. Lung tissue recruitment induced by a change of PEEP from 5 to 15 cmH2O was 16% (IQR 11–24%) in supine and 14.3% (IQR 8.4–22.6%) in prone position, as measured by CT scan analysis (paired t test p = 0.56). In this analysis, PEEP-induced recruitability as measured by R/I correlated with PEEP-induced lung recruitment as measured by CT scan, and could help to readjust PEEP in prone position. [ABSTRACT FROM AUTHOR]

Lung recruitment maneuvers following one-lung ventilation (OLV) increase the risk for the development of acute lung injury. The application of continuous negative extrathoracic pressure (CNEP) is gaining interest both in intubated and non-intubated patients. However, there is still a lack of knowledge on the ability of CNEP support to recruit whole lung atelectasis following OLV. We investigated the effects of CNEP following OLV on lung expansion, gas exchange, and hemodynamics. Ten pigs were anesthetized and mechanically ventilated with pressure-regulated volume control mode (PRVC; FiO2: 0.5, Fr: 30–35/min, VT: 7 mL/kg, PEEP: 5 cmH2O) for 1 hour, then baseline (BL) data for gas exchange (arterial partial pressure of oxygen, PaO2; and carbon dioxide, PaCO2), ventilation and hemodynamical parameters and lung aeration by electrical impedance tomography were recorded. Subsequently, an endobronchial blocker was inserted, and OLV was applied with a reduced VT of 5 mL/kg. Following a new set of measurements after 1 h of OLV, two-lung ventilation was re-established, combining PRVC (VT: 7 mL/kg) and CNEP (−15 cmH2O) without any hyperinflation maneuver and data collection was then repeated at 5 min and 1 h. Compared to OLV, significant increases in PaO2 (154.1 ± 13.3 vs. 173.8 ± 22.1) and decreases in PaCO2 (52.6 ± 11.7 vs. 40.3 ± 4.5 mmHg, p < 0.05 for both) were observed 5 minutes following initiation of CNEP, and these benefits in gas exchange remained after an hour of CNEP. Gradual improvements in lung aeration in the non-collapsed lung were also detected by electrical impedance tomography (p < 0.05) after 5 and 60 min of CNEP. Hemodynamics and ventilation parameters remained stable under CNEP. Application of CNEP in the presence of whole lung atelectasis proved to be efficient in improving gas exchange via recruiting the lung without excessive airway pressures. These benefits of combined CNEP and positive pressure ventilation may have particular value in relieving atelectasis in the postoperative period of surgical procedures requiring OLV.

Objectives: A retrospective study was performed to investigate the effects of incentive spirometry (IS)respiratory trainer device on lung recruitment in non-intubated moderate ARDS patients. Method: Moderate ARDS patients who non-intubated from January 2019 to October 2022 were enrolled to the lung recruitment group and the control group. Compared the PaO2/FiO2 (P/F)ratio, lung ultrasound (LUS) score, APACHE-II score, Maximum inspiratory volume during three days (baseline, Day1, Day2, Day3) and the rate of intubation, mean hospital stay, the 28-day in-hospital mortality and the 90-days in-hospital mortality between the two groups. Results: The lung recruitment group 118 patients (73 males, 47.6 ± 16.5y) and the control group 103 patients (62 males, 50.2 ± 14.8y) were included. The P/F ratios, APACHE-II scores, LUS scores, and the maximum inspiratory volume (ml) were significantly different between the two groups (P = 0.000, P = 0.014, P = 0.013 and P = 0.001, respectively).The P/F ratios were higher (252.6 ± 55.6 v.s, 166.96.9re, p = 0.035, day2), (269.8 ± 75.7 v.s 183.9 ± 68.6, p = 0.027, day3), the APACHE-II scores were lower (10.0 ± 2.4 v.s 15.3 1e l p = 0.025, day2), (8.0 ± 1.4 v.s 14.1 ± 2.7, p = 0.000, day3), the LUS scores were higher (16.2res wv.s 21.61.6w, p = 0.043, day2), (11.4 ± 5.9 v.s 20.3 ± 6.9, p = 0.004, day3), the maximum inspiratory volumes were higher (1722.3 ± 432.2 v.s 1310.70.732., p = 0.044, day2), (1913.5467.2 v.s 1299.79452.5, p = 0.018, day3) in Lung Recruitment group than that in Control group. These data at day1, day2, and day3 were significantly improvement than baseline in Lung Recruitment group. Only 36 patients (30.5%) in Lung Recruitment group needed to intubation, while 48 patients (46.6%) in Control group (p = 0.014). The mean hospital stay in lung recruitment group was lower (12.6 ± 4.6 v.s, 18.4 ± 5.3, P = 0.018). The 28-days and the 90-days in-hospital mortality were no statistical significance between the two groups (P = 0.414 and P = 0.418, respectively). Conclusions: Using IS to perform lung recruitment in moderate ARDS patients can improve maximum inspiratory volume, PaO2/FiO2 ratio, LUS scores, and APACHE-II score and reduce the rate of intubation and the mean hospital stay, but the 28 days and the 90-days in-hospital mortality were not improved.

Background: Morbid obesity may cause a restrictive condition, general anesthesia (GA) and supine posture both result in a decrease in lung capacity and Functional residual capacity (FRC), encouraging the development of atelectasis, altering the ventilation/perfusion ratio and raising the pulmonary shunt. This study evaluated the impact of recruitment maneuver (RM) and Transversus Abdominis Plane (TAP) block performed during laparoscopic bariatric surgery on spirometry, oxygenation, hemodynamic variables, opioid requirements and pain score assessed after surgery. Methods: This pilot prospective randomized controlled study included 80 patients scheduled for elective laparoscopic bariatric surgeries (e.g., laparoscopic sleeve gastrectomy, and laparoscopic gastric bypass) under GA. Patients were divided into four equal groups. All patients had received standardized postoperative analgesia regimen, group I (control group), group II received TAP block after intubation and before surgical incision, group III received RM after intubation and after pneumoperitoneal exsuf-flation, and group IV received RM after intubation and after pneumoperitoneal exsufflation and TAP block after intubation and before surgical incision. Results: Forced Vital Capacity "FVC", Forced Expiratory Volume "FEV1" were found to be significantly higher after operation in group IV compared to other groups. FEV1/FVC was insignificantly different among the four groups before and after operation. Intraoperative PaO2, PaO2/FiO2 were significantly higher in group III and IV compared to other groups. Numerical rating scale (NRS) at 1, 2, 4, 6 and 12hr had significantly decreased in group II and IV compared to other groups. Heart rate (HR) and mean arterial blood pressure (MAP) were insignificantly different among the four groups. Morphine consumption was significantly lower in group II and IV compared to other groups. Conclusions: TAP block combined with RM group exhibited better postoperative pulmonary function tests (PFTs). Intraoperative oxygenation was higher in RM groups. NRS and opioid consumption were lower in TAP groups in postoperative period. [ABSTRACT FROM AUTHOR]

Bilateral COVID-19 pneumonia is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and usually leads to life-threatening acute respiratory distress syndrome (ARDS). Treatment of patients with ARDS is difficult and usually involves protective mechanical ventilation and various types of recruitment maneuvers. A segmental lung recruitment maneuver by independent lung ventilation has been described as a successful recruitment maneuver in patients with lobar pneumonia, and may, therefore, be useful for the treatment of patients with bilateral COVID-19 pneumonia complicated by ARDS in the critical phase of the disease when all other therapeutic options have been exhausted. The aim of this case series was to present a case report of four mechanically ventilated patients with severe bilateral COVID-19 pneumonia complicated by ARDS using the segmental lung recruitment maneuver. The effect of the segmental lung recruitment maneuver was assessed by the increase in PaO2/FiO2 ratio and the lung ultrasound (LUS) scoring system (0 points—presence of sliding lungs with A-lines or one or two isolated B-lines; 1 point-moderate loss of lung ventilation with three to five B lines; 2 points-severe loss of lung ventilation with more than five B lines (B pattern); and 3 points-lung consolidation) determined 12, 24, and 48 h after segmental lung recruitment. In three of four patients with bilateral COVID-19 pneumonia complicated by ARDS, an increase in the PaO2/FiO2 ratio and an improvement in the LUS scoring system were observed 48 h after segmental lung recruitment. In conclusion, the segmental lung recruitment maneuver in patients with bilateral COVID-19 complicated by ARDS is an effective method of lung recruitment and may be a useful treatment method. [ABSTRACT FROM AUTHOR]

Background: Lung recruitment maneuvers (LRMs) improve lung volume at initiation of high-frequency oscillatory ventilation (HFOV), but it is unclear when to repeat LRMs. We evaluated the efficiency of scheduled LRMs. Methods: In a randomized controlled trial, extremely preterm infants on HFOV received either LRMs at 12-hour intervals and when clinically indicated (intervention) or only when clinically indicated (control). The primary outcome was the cumulative oxygen saturation index (OSI) over HFOV time, limited to 7 days. Additionally, LRMs were analyzed with respect to OSI improvement. Results: Fifteen infants were included in each group. The mean (SD) postmenstrual age and weight at HFOV start were 23 + 6 (0 + 5) weeks and 650 (115) g in the intervention group and 24 + 4 (0 + 6) weeks (p = 0.03) and 615 (95) g (p = 0.38) in the control group. The mean (SD) cumulative OSI amounted to 4.95 (1.72) in the intervention versus 5.30 (2.08) in the control group (p = 0.61). The mean (SD) number of LRMs in 12 h was 1.3 (0.2) in the intervention versus 1.1 (0.5) in the control group (p = 0.13). Performing LRM when FiO2 > 0.6 resulted in a mean OSI reduction of 3.6. Conclusion: Regular versus clinically indicated LRMs were performed with equal frequency in preterm infants during HFOV, and consequently, no difference in lung volume was observed. LRMs seem to be most efficient at high FiO2. Trial registration: ClinicalTrials.gov ID: NCT04289324 (28/02/2020). [ABSTRACT FROM AUTHOR]

One lung ventilation for lung resection surgery may affect oxygenation, impair lung mechanics and increase the incidence of acute lung injury. Lung recruitment maneuver may improve these conditions. This study was a prospective randomized controlled single blinded clinical trial. Forty patients scheduled for elective lung resection surgeries using one lung ventilation under general anaesthesia were randomly allocated into two groups. Control (C) group was subjected to conventional mechanical ventilation of tidal volume of 8 ml/kg and 5 ml/kg for total lung ventilation (TLV) and one lung ventilation (OLV), respectively, and PEEP of 5 cmH2O and (LR) group which was subjected to stepwise lung recruitment twice: The first lung recruitment (LR1) was performed after (OLV) to the dependent lung, while the second lung recruitment (LR2) was performed after resuming (TLV). Arterial blood gases, lung mechanics and serum tumor necrosis factor alpha were recorded at multiple time points during the study. The proposal and raw data were registered on PACTR as PACTR202001518687696. There was a significant decrease in PaO2/FIO2 during OLV baseline in comparison to TLV baseline (P = < 0.001*) in both groups. While, in LR group, there was a significant increase in PaO2/FIO2 and dynamic compliance during OLV-20 min after recruitment (P = <0.001*), during TLV-20 min after recruitment (P = < 0.001*) and during TLV-end (P = <0.001*). TNF-⍺ level was significantly higher in control group 1 h after surgery and 24 h postoperative. Stepwise lung recruitment maneuver improved oxygenation parameters and lung mechanics during lung resection surgery and decreased the expression of lung injury biomarkers. Abbreviations: OLV: one lung ventilation; TLV: total lung ventilation; RM: recruitment maneuver; LR: lung recruitment; TNF-⍺: tumor necrosis factor alpha; VCV: volume controlled ventilation; PCV: pressure controlled ventilation; VT: tidal volume; FIO2: fraction of inspired oxygen; ALI: acute lung injury; ppoFEV1%: predicted postoperative forced expiratory volume in 1 s; BAL: Bronchoalveolar lavage. [ABSTRACT FROM AUTHOR]

Abstract Background Lung recruitment is a maneuver used to decrease the length of intubation in preterm neonates. This study aimed to compare the therapeutic efficacy of lung recruitment plus intubation-surfactant-extubation (INSURE) procedure and INSURE alone for the preterm neonates with respiratory distress syndrome. Methods From 2017 to 2019, 184 preterm neonates (gestational age 24–32 weeks) with respiratory distress syndrome were enrolled and randomized into the lung recruitment group receiving lung recruitment (25 cm H2O, 15 s) plus INSURE and the control group receiving INSURE only. The primary outcome was the need for mechanical ventilation (MV) within 72 h after extubation. The secondary outcomes included duration of MV, noninvasive ventilation, total oxygen therapy, hospitalization time, and complications. Results Compared to the control group, the lung recruitment group had a significantly lower proportion of preterm neonates requiring MV within 72 h after extubation (23% vs. 38%, P = 0.025) and pulmonary surfactant administration, as well as a shorter MV duration. There was no significant difference in the incidences of complications (all P > 0.05) and in-hospital mortality (2% vs. 4%, P = 0.4) between the lung recruitment group and control group. Multivariate logistic regression analysis demonstrated that the control group had a 2.17-time higher risk of requiring MV than the lung recruitment group (AOR: 2.17, 95% CI: 1.13–4.18; P = 0.021). Compared with infants with a normotensive mother, infants with a hypertensive mother have a 2.41-time higher risk of requiring MV (AOR: 2.41, 95% CI: 1.15–5.05; P = 0.020). Conclusion Lung recruitment plus INSURE can reduce the need for MV within 72 h after extubation and did not increase the incidence of complications and mortality. Trial registration Chinese Clinical Trial Registry ChiCTR1800020125 , retrospectively registered on December 15, 2018.

To determine whether end-expiratory lung volume measured with volumetric capnography (EELVCO2) can individualize positive end-expiratory pressure (PEEP) setting during laparoscopic surgery. We studied patients undergoing laparoscopic surgery subjected to Fowler (F-group; n = 20) or Trendelenburg (T-group; n = 20) positions. EELVCO2 was measured at 0° supine (baseline), during capnoperitoneum (CP) at 0° supine, during CP with Fowler (head up + 20°) or Trendelenburg (head down - 30°) positions and after CP back to 0° supine. PEEP was adjusted to preserve baseline EELVCO2 during and after CP. Baseline EELVCO2 was statistically similar to predicted FRC in both groups. At supine and CP, EELVCO2 decreased from baseline values in F-group [median and IQR 2079 (768) to 1545 (725) mL; p = 0.0001] and in T-group [2164 (789) to 1870 (940) mL; p = 0.0001]. Change in body position maintained EELVCO2 unchanged in both groups. PEEP adjustments from 5.6 (1.1) to 10.0 (2.5) cmH2O in the F-group (p = 0.0001) and from 5.6 (0.9) to 10.0 (2.6) cmH2O in T-group (p = 0.0001) were necessary to reach baseline EELVCO2 values. EELVCO2 increased close to baseline with PEEP in the F-group [1984 (600) mL; p = 0.073] and in the T-group [2175 (703) mL; p = 0.167]. After capnoperitoneum and back to 0° supine, PEEP needed to maintain EELVCO2 was similar to baseline PEEP in F-group [5.9 (1.8) cmH2O; p = 0.179] but slightly higher in the T-group [6.5 (2.2) cmH2O; p = 0.006]. Those new PEEP values gave EELVCO2 similar to baseline in the F-group [2039 (980) mL; p = 0.370] and in the T-group [2150 (715) mL; p = 0.881]. Breath-by-breath noninvasive EELVCO2 detected changes in lung volume induced by capnoperitoneum and body position and was useful to individualize the level of PEEP during laparoscopy.Trial registry: Clinicaltrials.gov NCT03693352. Protocol started 1st October 2018. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pediatric patients with ARDS will on occasion need venovenous extracorporeal membrane oxygenation (VV-ECMO) for organ support. As these patients recover, they may benefit from lung recruitment maneuvers including flexible bronchoscopy (FB). The objective of this study was to assess the clinical course of patients who underwent FB while on VV-ECMO for ARDS. METHODS: This was a secondary analysis of a retrospective multi-center cohort at 10 United States pediatric academic quaternary care centers. Data were collected on 204 subjects age 14 d-18 y on VV-ECMO. RESULTS: 271 FBs were performed on 129 (63%) subjects. Pre-FB tidal volume was 1.8 mL/kg compared to 2.22 mL/kg following FB (P = .007). Dynamic compliance also improved from pre-FB to post-FB (2.23 vs 3.04 mL/cm H2O, P = .005). There was a low incidence of complications following FB (3.1%). Subjects in the FB group had fewer ECMO-free days (EFDs) (17.9 vs 22.1 d, P < .001), fewer ventilator-free days (VFDs) (40.0 vs 46.5 d, P = .001), and longer ICU length of stay (LOS) (18 vs 32 d, P < .001). Subjects in the early versus late FB group had more EFDs (19.4 vs 15.2 d, P = .003), more VFDs (43.0 vs 34.0 d, P = .004), and shorter ICU LOS (27.5 vs 35.5 d, P = .045). Mortality in the subjects who had at least one FB was 27.1% compared to 40% in the subjects who did not have a FB while on VV-ECMO (P = .057). CONCLUSIONS: FB can be performed on patients while anticoagulated on VV-ECMO with a low incidence of complications. FB may be beneficial especially when performed early in the course of VV-ECMO. [ABSTRACT FROM AUTHOR]

Bedside lung ultrasound may be an effective method for the assessment of lung recruitment in newborns with extracorporeal membrane oxygenation (ECMO). We report a case of a neonate who had severe hypoxemia with persistent pulmonary hypertension and massive pneumothorax due to meconium aspiration syndrome and was treated with ECMO. Positive pressure mechanical ventilation resulted in persistent massive air leakage from the disrupted pulmonary tissue. When ECMO was initiated, a "total lung rest" ventilation strategy was used to facilitate healing of the lung rupture and absorption of the pneumothorax. After complete absorption of the pneumothorax, lung recruitment was performed by progressively increasing the positive end-expiratory pressure under the guidance of lung ultrasound. Bedside lung ultrasound was successfully used to assess pneumothorax absorption and improvement of pulmonary inflammation and successfully guided the recruitment of collapsed alveoli and the withdrawal of ECMO. [ABSTRACT FROM AUTHOR]

Lung ultrasound (LUS) can be used to diagnose various neonatal lung diseases. It more sensitively diagnoses pulmonary edema, pneumothorax, pulmonary consolidation, and atelectasis than traditional X-ray and quickly determines the cause of dyspnea. As a component of severe ultrasound, LUS enables rapid bedside visualization of lung diseases and plays a major role in guiding the differential diagnosis of disease, ventilator treatment, and lung recruitment. This study introduced the application of LUS in the diagnosis and treatment of critically ill neonates with lung diseases.

Background: Identification of lung parenchyma on computer tomographic (CT) scans in the research setting is done semi-automatically and requires cumbersome manual correction. This is especially true in pathological conditions, hindering the clinical application of aeration compartment (AC) analysis. Deep learning based algorithms have lately been shown to be reliable and time-efficient in segmenting pathologic lungs. In this contribution, we thus propose a novel 3D transfer learning based approach to quantify lung volumes, aeration compartments and lung recruitability. Methods: Two convolutional neural networks developed for biomedical image segmentation (uNet), with different resolutions and fields of view, were implemented using Matlab. Training and evaluation was done on 180 scans of 18 pigs in experimental ARDS (u 2 Net Pig ) and on a clinical data set of 150 scans from 58 ICU patients with lung conditions varying from healthy, to COPD, to ARDS and COVID-19 (u 2 Net Human ). One manual segmentations (MS) was available for each scan, being a consensus by two experts. Transfer learning was then applied to train u 2 Net Pig on the clinical data set generating u 2 Net Transfer . General segmentation quality was quantified using the Jaccard index (JI) and the Boundary Function score (BF). The slope between JI or BF and relative volume of non-aerated compartment (S JI and S BF , respectively) was calculated over data sets to assess robustness toward non-aerated lung regions. Additionally, the relative volume of ACs and lung volumes (LV) were compared between automatic and MS. Results: On the experimental data set, u 2 Net Pig resulted in JI = 0.892 [0.88 : 091] (median [inter-quartile range]), BF = 0.995 [0.98 : 1.0] and slopes S JI = −0.2 {95% conf. int. −0.23 : −0.16} and S BF = −0.1 {−0.5 : −0.06}. u 2 Net Human showed similar performance compared to u 2 Net Pig in JI , BF but with reduced robustness S JI = −0.29 {−0.36 : −0.22} and S BF = −0.43 {−0.54 : −0.31}. Transfer learning improved overall JI = 0.92 [0.88 : 0.94], P < 0.001, but reduced robustness S JI = −0.46 {−0.52 : −0.40}, and affected neither BF = 0.96 [0.91 : 0.98] nor S BF = −0.48 {−0.59 : −0.36}. u 2 Net Transfer improved JI compared to u 2 Net Human in segmenting healthy (P = 0.008), ARDS (P < 0.001) and COPD (P = 0.004) patients but not in COVID-19 patients (P = 0.298). ACs and LV determined using u 2 Net Transfer segmentations exhibited < 5% volume difference compared to MS. Conclusion: Compared to manual segmentations, automatic uNet based 3D lung segmentation provides acceptable quality for both clinical and scientific purposes in the quantification of lung volumes, aeration compartments, and recruitability. [ABSTRACT FROM AUTHOR]

ObjectiveTo evaluate the effect of volume guarantee (VG) combined with high-frequency oscillatory ventilation (HFOV) on respiratory and other physiological parameters immediately after lung recruitment and surfactant administration in HFOV elective ventilated extremely low gestational age newborns (ELGAN) with respiratory distress syndrome (RDS).DesignObservational study.SettingTertiary neonatal intensive care unit.PatientsTwenty-two ELGANs of 25.5 ± 1.1 weeks of gestational age requiring invasive mechanical ventilation and surfactant administration for RDS during the first 6 h of life.InterventionsAll infants intubated in delivery room, were managed with elective HFOV and received surfactant after a lung recruitment manoeuver. Eleven infants received HFOV + VG and were compared with a control group of 11 infants receiving HFOV alone. HFOV was delivered in both groups by Dräger Babylog VN500 ventilator (Dräger, Lubeck, Germany).Main Outcome MeasuresVariations and fluctuations of delivered high-frequency tidal volume (VThf), fluctuation of pressure amplitude (ΔP) and partial pressure of CO2 (pCO2) levels after recruitment manoeuver and immediately after surfactant administration, in HFOV + VG vs. HFOV ventilated infants.ResultsThere were no significant differences in the two groups at starting ventilation with or without VG. The mean applied VThf per kg was 1.7 ± 0.3 ml/kg in the HFOV group and 1.7 ± 0.1 ml/kg in the HFOV + VG group. Thirty minutes after surfactant administration, HFOV group had a significant higher VThf/Kg than HFOV + VG (2.1 ± 0.3 vs. 1.6 ± 0.1 ml/kg, p < 0.0001) with significantly lower pCO2 levels (43.1 ± 3.8 vs. 46.8 ± 1.5 mmHg, p = 0.01), 54.4% of patients having pCO2 below 45 mmHg. Measured post-surfactant ΔP values were higher in HFOV group (17 ± 3 cmH2O) than in HFOV + VG group (13 ± 3 cmH2O, p = 0.01).ConclusionHFOV + VG maintains pCO2 levels within target range and reduces VThf delivered variations more consistently than HFOV alone after surfactant administration.

Background: Stepwise lung recruitment maneuvers (LRMs) may be used in ventilated preterm infants. However, its use in high-frequency oscillation with volume guarantee (HFO-VG) is not well studied. Methods: Preterm infants treated with HFO-VG who had LRMs were identified. Patient and respiratory parameters were recorded. Results: Ten infants, median GA 25+6 (IQR 24+2–27+0) weeks, and 21 LRMs were identified. LRMs were performed at a median age of 26 days, with a starting MAP of 16 (14–17) cm H2O and the highest MAP of 23.5 (22.0–24.8) cm H2O. Most (76%) resulted in immediate improved SpO2/FiO2. There were no sustained differences in median oxygen saturation index (8.4 vs. 9, p = 0.09), SpO2/FiO2 (1.8 vs. 1.8, p = 0.8), ∆P (21 vs. 23, p = 0.64), or transcutaneous CO2 (58 vs. 60, p = 0.84) in 24 h before and after LRMs. Conclusions: In preterm infants with evolving bronchopulmonary dysplasia, LRMs on HFO-VG did not result in sustained improvement to oxygenation or ventilation. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed at investigating the mechanisms underlying the oxygenation response to proning and recruitment maneuvers in coronavirus disease 2019 (COVID-19) pneumonia. Methods: Twenty-five patients with COVID-19 pneumonia, at variable times since admission (from 1 to 3 weeks), underwent computed tomography (CT) lung scans, gas-exchange and lung-mechanics measurement in supine and prone positions at 5 cmH2O and during recruiting maneuver (supine, 35 cmH2O). Within the non-aerated tissue, we differentiated the atelectatic and consolidated tissue (recruitable and non-recruitable at 35 cmH2O of airway pressure). Positive/negative response to proning/recruitment was defined as increase/decrease of PaO2/FiO2. Apparent perfusion ratio was computed as venous admixture/non aerated tissue fraction. Results: The average values of venous admixture and PaO2/FiO2 ratio were similar in supine-5 and prone-5. However, the PaO2/FiO2 changes (increasing in 65% of the patients and decreasing in 35%, from supine to prone) correlated with the balance between resolution of dorsal atelectasis and formation of ventral atelectasis (p = 0.002). Dorsal consolidated tissue determined this balance, being inversely related with dorsal recruitment (p = 0.012). From supine-5 to supine-35, the apparent perfusion ratio increased from 1.38 ± 0.71 to 2.15 ± 1.15 (p = 0.004) while PaO2/FiO2 ratio increased in 52% and decreased in 48% of patients. Non-responders had consolidated tissue fraction of 0.27 ± 0.1 vs. 0.18 ± 0.1 in the responding cohort (p = 0.04). Consolidated tissue, PaCO2 and respiratory system elastance were higher in patients assessed late (all p < 0.05), suggesting, all together, "fibrotic-like" changes of the lung over time. Conclusion: The amount of consolidated tissue was higher in patients assessed during the third week and determined the oxygenation responses following pronation and recruitment maneuvers. [ABSTRACT FROM AUTHOR]

Background: Lung recruitment is a maneuver used to decrease the length of intubation in preterm neonates. This study aimed to compare the therapeutic efficacy of lung recruitment plus intubation-surfactant-extubation (INSURE) procedure and INSURE alone for the preterm neonates with respiratory distress syndrome.Methods: From 2017 to 2019, 184 preterm neonates (gestational age 24-32 weeks) with respiratory distress syndrome were enrolled and randomized into the lung recruitment group receiving lung recruitment (25 cm H2O, 15 s) plus INSURE and the control group receiving INSURE only. The primary outcome was the need for mechanical ventilation (MV) within 72 h after extubation. The secondary outcomes included duration of MV, noninvasive ventilation, total oxygen therapy, hospitalization time, and complications.Results: Compared to the control group, the lung recruitment group had a significantly lower proportion of preterm neonates requiring MV within 72 h after extubation (23% vs. 38%, P = 0.025) and pulmonary surfactant administration, as well as a shorter MV duration. There was no significant difference in the incidences of complications (all P > 0.05) and in-hospital mortality (2% vs. 4%, P = 0.4) between the lung recruitment group and control group. Multivariate logistic regression analysis demonstrated that the control group had a 2.17-time higher risk of requiring MV than the lung recruitment group (AOR: 2.17, 95% CI: 1.13-4.18; P = 0.021). Compared with infants with a normotensive mother, infants with a hypertensive mother have a 2.41-time higher risk of requiring MV (AOR: 2.41, 95% CI: 1.15-5.05; P = 0.020).Conclusion: Lung recruitment plus INSURE can reduce the need for MV within 72 h after extubation and did not increase the incidence of complications and mortality.Trial Registration: Chinese Clinical Trial Registry ChiCTR1800020125 , retrospectively registered on December 15, 2018. [ABSTRACT FROM AUTHOR]

Abstract Background Lung recruitment at birth has been advocated as an effective method of improving the respiratory transition at birth. Sustained inflations (SI) and dynamic positive end-expiratory pressure (PEEP) were assessed in clinical and animal studies to define the optimal level. Our working hypothesis was that very low gestational age infants (VLGAI)

Abstract Purpose It has been suggested that, by recruiting lung regions and enlarging the distribution volume of the cold indicator, increasing the positive end-expiratory pressure (PEEP) may lead to an artefactual overestimation of extravascular lung water (EVLW) by transpulmonary thermodilution (TPTD). Methods In 60 ARDS patients, we measured EVLW (PiCCO2 device) at a PEEP level set to reach a plateau pressure of 30 cmH2O (HighPEEPstart) and 15 and 45 min after decreasing PEEP to 5 cmH2O (LowPEEP15′ and LowPEEP45′, respectively). Then, we increased PEEP back to the baseline level (HighPEEPend). Between HighPEEPstart and LowPEEP15′, we estimated the degree of lung derecruitment either by measuring changes in the compliance of the respiratory system (Crs) in the whole population, or by measuring the lung derecruited volume in 30 patients. We defined patients with a large derecruitment from the other ones as patients in whom the Crs changes and the measured derecruited volume were larger than the median of these variables observed in the whole population. Results Reducing PEEP from HighPEEPstart (14 ± 2 cmH2O) to LowPEEP15′ significantly decreased EVLW from 20 ± 4 to 18 ± 4 mL/kg, central venous pressure (CVP) from 15 ± 4 to 12 ± 4 mmHg, the arterial oxygen tension over inspired oxygen fraction (PaO2/FiO2) ratio from 184 ± 76 to 150 ± 69 mmHg and lung volume by 144 [68–420] mL. The EVLW decrease was similar in “large derecruiters” and the other patients. When PEEP was re-increased to HighPEEPend, CVP, PaO2/FiO2 and EVLW significantly re-increased. At linear mixed effect model, EVLW changes were significantly determined only by changes in PEEP and CVP (p

Abstract Background Postextubation high-flow nasal cannula (HFNC) is used as a support therapy in high-risk patients in ICU. This study aimed to determine the effects of HFNC therapy on lung recruitment and overdistension assessed by electrical impedance tomography (EIT). Methods Twenty-four patients who received HFNC within 24 h after extubation were prospectively enrolled in this study. EIT was used to monitor regional lung ventilation distributions at baseline (conventional oxygen therapy) and three flow rate levels of HFNC therapy (20, 40, and 60 L/min). Change of end-expiratory lung impedance (ΔEELI), regional recruitment (recruited-pixels) and overdistension (overdistended-pixels), and lung strain change were determined by EIT. EIT images were equally divided into four ventral-to-dorsal horizontal regions of interest (ROIs 1, 2, 3, and 4). “Overdistension-by HFNC” due to HFNC is defined as an increase of overdistened-pixels > 10 than baseline. Patients were divided into two groups: (1) high potential of recruitment (HPR), recruited-pixels > 10 pixels at 60 L/min than baseline, and (2) low potential of recruitment (LPR), recruited-pixels

Background: Recruitment maneuvers are a dynamic process of transient increases in transpulmonary pressure intended to open unstable airless alveoli. Due to concerns regarding the hemodynamic consequences of recruitment maneuvers in children with heart disease, these maneuvers have not been widely utilized in this population. The objective of this study was to demonstrate the safety and efficacy of lung recruitment maneuvers in post-operative pediatric cardiac patients. We hypothesized that multiple recruitment maneuvers are physiologically beneficial and hemodynamically tolerated in children with congenital cardiac disease. Methods: Retrospective chart review was conducted of post-operative cardiac surgical subjects who received recruitment maneuvers, as well as a matched control group who did not, at a Cardiac ICU in a quaternary care free-standing children’s hospital. Repetitive lung recruitment maneuvers using incremental positive end-expiratory pressure were performed. Hemodynamic and respiratory physiologic variables were recorded. Results: Sixty-one post-operative cardiac subjects had a total of 435 lung recruitment maneuvers. Assessment of hemodynamic tolerability demonstrated no change in MAP, HR, or CVP during or after the maneuvers. There was a 28% increase in dynamic compliance following recruitment maneuvers (p

Bilateral COVID-19 pneumonia is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and usually leads to life-threatening acute respiratory distress syndrome (ARDS). Treatment of patients with ARDS is difficult and usually involves protective mechanical ventilation and various types of recruitment maneuvers. A segmental lung recruitment maneuver by independent lung ventilation has been described as a successful recruitment maneuver in patients with lobar pneumonia, and may, therefore, be useful for the treatment of patients with bilateral COVID-19 pneumonia complicated by ARDS in the critical phase of the disease when all other therapeutic options have been exhausted. The aim of this case series was to present a case report of four mechanically ventilated patients with severe bilateral COVID-19 pneumonia complicated by ARDS using the segmental lung recruitment maneuver. The effect of the segmental lung recruitment maneuver was assessed by the increase in PaO2/FiO2 ratio and the lung ultrasound (LUS) scoring system (0 points—presence of sliding lungs with A-lines or one or two isolated B-lines; 1 point-moderate loss of lung ventilation with three to five B lines; 2 points-severe loss of lung ventilation with more than five B lines (B pattern); and 3 points-lung consolidation) determined 12, 24, and 48 h after segmental lung recruitment. In three of four patients with bilateral COVID-19 pneumonia complicated by ARDS, an increase in the PaO2/FiO2 ratio and an improvement in the LUS scoring system were observed 48 h after segmental lung recruitment. In conclusion, the segmental lung recruitment maneuver in patients with bilateral COVID-19 complicated by ARDS is an effective method of lung recruitment and may be a useful treatment method.

The article presents the discussion on lung recruitment (LR) being the use of an increased transient sustained transpulmonary pressure. Topics include LR showing both beneficial and negative effects, thereby making patient selection as well as timing of recruitment very important; and expected result showing an improvement in the patient's gaseous exchange and lung mechanics.

Introduction: The effect of positive end-expiratory pressure (PEEP) depends closely on the potential for lung recruitment. Bedside assessment of lung recruitability is crucial for personalized lung-protective mechanical ventilation in acute respiratory distress syndrome (ARDS) patients. Methods: We developed a transoesophageal lung ultrasound (TE-LUS) method in which a quantitative (computer-assisted) grayscale determination served as a guide to PEEP-induced lung recruitment. The method is based on the following hypothesis: when the PEEP increases, inflation of the recruited alveoli leads to significant changes in the air/water ratio. Normally ventilated areas are hypoechoic because the ultrasound waves are weakly reflected while poorly aerated areas or non-aerated areas are hyperechoic. We calculated the TE-LUS re-aeration score (RAS) as the ratio of the mean gray scale level at low PEEP to that value at high PEEP for the lower and upper lobes. A RAS > 1 indicated an increase in ventilated area. We used this new method to detect changes in ventilation in patients with a low (<0.5) vs. high (≥0.5) recruitment-to-inflation (R/I) ratio (i.e., the ratio between the recruited lung compliance and the respiratory system compliance at low PEEP). Results: We included 30 patients with moderate-to-severe ARDS. In patients with a high R/I ratio, the TE-LUS RAS was significantly higher in the lower lobes than in the upper lobes (1.20 [1.12–1.63] vs. 1.05 [0.89–1.38]; p = 0.05). Likewise, the TE-LUS RAS in the lower lobes was significantly higher in the high R/I group than in the low R/I group (1.20 [1.12–1.63] vs. 1.07 [1.00–1.20]; p = 0.04). Conclusion: The increase in PEEP induces a substantial gain in the ventilation detected by TE-LUS of poorly or non-aerated lower lobes (dependent lung regions), especially in patients with a high R/I ratio. [ABSTRACT FROM AUTHOR]