Lung Recruitment Maneuver Research Articles

Impact of Stepwise Recruitment Maneuvers on Cerebral Hemodynamics: Experimental Study in Neonatal Model.

Lung recruitment maneuvers (LRMs) have been demonstrated to be effective in avoiding atelectasis during general anesthesia in the pediatric population. Performing these maneuvers is safe at the systemic hemodynamic and respiratory levels. We aimed to evaluate the impact of a stepwise LRM and individualized positive end-expiratory pressure (PEEP) on cerebral hemodynamics in an experimental neonatal model. Eleven newborn pigs (less than 72 h old, 2.56 ± 0.18 kg in weight) were included in the study. The LRM was performed under pressure-controlled ventilation with a constant driving pressure (15 cmH2O) in a stepwise increasing PEEP model. The target peak inspiratory pressure (PIP) was 30 cmH2O and the PEEP was 15 cmH2O. The following hemodynamic variables were monitored using the PICCO® system: mean arterial pressure (MAP), central venous pressure (CVP), and cardiac output (CO). The cerebral hemodynamics variables monitored were intracranial pressure (ICP) (with an intraparenchymal Camino® catheter) and cerebral oxygen saturation (rSO2) (with the oximetry monitor INVOS 5100® system). The following respiratory parameters were monitored: oxygen saturation, fraction of inspired oxygen, partial pressure of oxygen, end-tidal carbon dioxide pressure, Pmean, PEEP, static compliance (Cstat), and dynamic compliance (Cdyn). All LRMs were safely performed as scheduled without any interruptions. Systemic hemodynamic stability was maintained during the lung recruitment maneuver. No changes in ICP occurred. We observed an improvement in rSO2 after the maneuver (+5.8%). Stepwise LRMs are a safe tool to avoid atelectasis. We did not observe an impairment in cerebral hemodynamics but an improvement in cerebral oxygenation.

Effect of individualized intraoperative lung recruitment maneuver on postoperative pulmonary complications in patients undergoing upper abdominal surgeries under general anesthesia

ABSTRACT 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.

Effects of lung recruitment maneuvers using mechanical ventilator on preterm hemodynamics

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.

Rebounds of sevoflurane concentration during simulated trigger-free pediatric and adult anesthesia

BackgroundIn trigger-free anesthesia a volatile anesthetic concentration of 5 parts per million (ppm) should not be exceeded. According to European Malignant Hyperthermia Group (EMHG) guideline, this may be achieved by removing the vapor, changing the anesthetic breathing circuit and renewing the soda lime canister followed by flushing with O2 or air for a workstation specific time. Reduction of the fresh gas flow (FGF) or stand-by modes are known to cause rebound effects. In this study, simulated trigger-free pediatric and adult ventilation was carried out on test lungs including ventilation maneuvers commonly used in clinical practice. The goal of this study was to evaluate whether rebounds of sevoflurane develop during trigger-free anesthesia.MethodsA Dräger® Primus® was contaminated with decreasing concentrations of sevoflurane for 120 min. Then, the machine was prepared for trigger-free anesthesia according to EMHG guideline by changing recommended parts and flushing the breathing circuits using 10 or 18 l⋅min− 1 FGF. The machine was neither switched off after preparation nor was FGF reduced. Simulated trigger-free ventilation was performed with volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) including various ventilation maneuvers like pressure support ventilation (PSV), apnea, decreased lung compliance (DLC), recruitment maneuvers, prolonged expiration and manual ventilation (MV). A high-resolution ion mobility spectrometer with gas chromatographic pre-separation was used to measure sevoflurane in the ventilation gas mixture in a 20 s interval.ResultsImmediately after start of simulated anesthesia, there was an initial peak of 11–18 ppm sevoflurane in all experiments. The concentration dropped below 5 ppm after 2–3 min during adult and 4–18 min during pediatric ventilation. Other rebounds of sevoflurane > 5 ppm occurred after apnea, DLC and PSV. MV resulted in a decrease of sevoflurane < 5 ppm within 1 min.ConclusionThis study shows that after guideline-compliant preparation for trigger-free ventilation anesthetic machines may develop rebounds of sevoflurane > 5 ppm during typical maneuvers used in clinical practice. The changes in rate and direction of internal gas flow during different ventilation modes and maneuvers are possible explanations. Therefore, manufacturers should provide machine-specific washout protocols or emphasize the use of active charcoal filters (ACF) for trigger-free anesthesia.

Lung recruitment by continuous negative extra-thoracic pressure support following one-lung ventilation: an experimental study.

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: 7mL/kg, PEEP: 5 cmH2O) for 1hour, 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 5mL/kg. Following a new set of measurements after 1h of OLV, two-lung ventilation was re-established, combining PRVC (VT: 7mL/kg) and CNEP (-15 cmH2O) without any hyperinflation maneuver and data collection was then repeated at 5min and 1h. 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 ± 4.5mmHg, p < 0.05 for both) were observed 5minutes 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 60min 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.

Respiratory Mechanics: Revisiting the Appraisement of Lung Recruitment.

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.

MODERN CONCEPTS OF ARTIFICIAL LUNG VENTILATION DURING GENERAL ANESTHESIA IN CANCER PATIENTS: А LITERATURE REVIEW

Relevance: Among patients who have undergone extensive surgical interventions under general anesthesia with artificial ventilation (ventilator), various postoperative respiratory complications of an obstructive or restrictive nature are often found&#x0D; The study aimed to generalizе current data from systematic reviews, meta-analyses, and scientific publications on the use of preventive and therapeutic strategies for lung ventilation to improve the quality of anesthetic care for cancer patients.&#x0D; Methods: The PubMed Electronic Database (NCBI) was searched to identify randomized controlled and prospective observational studies, systematic reviews, and meta-analyses, as well as scientific articles published in English between 2016 and 2023 that focused on the results of application and comparison of lung protective ventilation strategies with conventional mechanical ventilation in patients undergoing major and prolonged surgery.&#x0D; Results: As a result of a comparison of data from a review of large-scale scientific studies and articles, a relationship was established between the use of a protective lung ventilation strategy with a low tidal volume (6-8 ml/kg of ideal body weight), in combination with individualized PEEP, periodic lung recruitment maneuvers and significant improvement in clinical outcomes, respiratory complications, early mortality and length of hospital stay in patients undergoing surgery.&#x0D; Conclusion: Using protective lung ventilation during anesthesia during major surgical interventions reduces the incidence of postoperative pulmonary complications.

MODERN CONCEPTS OF ARTIFICIAL LUNG VENTILATION DURING GENERAL ANESTHESIA IN CANCER PATIENTS: А LITERATURE REVIEW

Relevance: Among patients who have undergone extensive surgical interventions under general anesthesia with artificial ventilation (ventilator), various postoperative respiratory complications of an obstructive or restrictive nature are often found&#x0D; The study aimed to generalizе current data from systematic reviews, meta-analyses, and scientific publications on the use of preventive and therapeutic strategies for lung ventilation to improve the quality of anesthetic care for cancer patients.&#x0D; Methods: The PubMed Electronic Database (NCBI) was searched to identify randomized controlled and prospective observational studies, systematic reviews, and meta-analyses, as well as scientific articles published in English between 2016 and 2023 that focused on the results of application and comparison of lung protective ventilation strategies with conventional mechanical ventilation in patients undergoing major and prolonged surgery.&#x0D; Results: As a result of a comparison of data from a review of large-scale scientific studies and articles, a relationship was established between the use of a protective lung ventilation strategy with a low tidal volume (6-8 ml/kg of ideal body weight), in combination with individualized PEEP, periodic lung recruitment maneuvers and significant improvement in clinical outcomes, respiratory complications, early mortality and length of hospital stay in patients undergoing surgery.&#x0D; Conclusion: Using protective lung ventilation during anesthesia during major surgical interventions reduces the incidence of postoperative pulmonary complications.

Respiratory Rate as a Factor in Lung Injury-Not Just What You Set, but How You Set.

Respiratory Rate as a Factor in Lung Injury-Not Just What You Set, but How You Set.

Technique for xenogeneic cross-circulation to support human donor lungs ex vivo.

Xenogeneic cross-circulation (XC) is an experimental method for ex vivo organ support and recovery that could expand the pool of donor lungs suitable for transplantation. The objective of this study was to establish and validate a standardized, reproducible, and broadly applicable technique for performing xenogeneic XC to support and recover injured human donor lungs ex vivo. Human donor lungs (n=9) declined for transplantation were procured, cannulated, and subjected to 24 hours of xenogeneic XC with anesthetized xeno-support swine (Yorkshire/Landrace) treated with standard immunosuppression (methylprednisolone, mycophenolate mofetil, tacrolimus) and complement-depleting cobra venom factor. Standard lung-protective perfusion and ventilation strategies, including periodic lung recruitment maneuvers, were used throughout xenogeneic XC. Every 6 hours, ex vivo donor lung function (gas exchange, compliance, airway pressures, pulmonary vascular dynamics, lung weight) was evaluated. At the experimental endpoint, comprehensive assessments of the lungs were performed by bronchoscopy, histology, and electron microscopy. Student's t-test and 1-way analysis of variance with Dunnett's post-hoc test was performed, and p < 0.05 was considered significant. After 24 hours of xenogeneic XC, gas exchange (PaO2/FiO2) increased by 158% (endpoint: 364 ± 142 mm Hg; p=0.06), and dynamic compliance increased by 127% (endpoint: 46 ± 20 ml/cmH2O; p=0.04). Airway pressures, pulmonary vascular pressures, and lung weight remained stable (p > 0.05) and within normal ranges. Over 24 hours of xenogeneic XC, gross and microscopic lung architecture were preserved: airway bronchoscopy and parenchymal histomorphology appeared normal, with intact blood-gas barrier. Xenogeneic cross-circulation is a robust method for ex vivo support, evaluation, and improvement of injured human donor lungs declined for transplantation.

Effect of ultrasound-guided lung recruitment manoeuvre on perioperative atelectasis during laparoscopy in young infants: A randomised controlled trial

BackgroundPneumoperitoneum is a risk factor for perioperative atelectasis in infants. This research aimed to investigate whether lung recruitment manoeuvres guided by ultrasound are more effective for young infants (<3 months) during laparoscopy under general anaesthesia. MethodsYoung infants (<3 months) undergoing general anaesthesia during laparoscopic surgery (>2 h) were randomised to either conventional lung recruitment (control group) or ultrasound-guided lung recruitment (ultrasound group) once per hour. Mechanical ventilation was started with a tidal volume of 8 mL·kg−1, positive end-expiratory pressure of 6 cm H2O and 40% inspired oxygen fraction. Lung ultrasound (LUS) was performed four times (T1 was performed 5 min after intubation and before pneumoperitoneum set, T2 was performed after pneumoperitoneum, T3 was performed 1 min after surgery, and T4 was performed before being discharged from post-anaesthesia care unit [PACU]) in each infant. The primary outcome was the incidence of significant atelectasis at T3 and T4 (defined by LUS consolidation score ≥ 2 in any region). Results62 babies were enrolled in the experiment and 60 infants were included in the analysis. Before the recruitment, atelectasis was similar between infants randomised to the control or ultrasound group at T1 (83.3% vs 80.0%; P = 0.500) and T2 (83,3% vs 76.7%; P = 0.519). The incidence of atelectasis at T3 and T4 were lower in the ultrasound group (26.7% and 33.3%), compared with infants randomised to conventional lung recruitment (66.7% and 70%) (P = 0.002; P = 0.004; respectively). ConclusionsUltrasound-guided alveolar recruitment reduced the perioperative incidence of atelectasis in infants <3 months during laparoscopy under general anaesthesia.

The importance of lung recruitability: A novel ultrasound pattern to guide lung recruitment in neonates.

Lung Ultrasound (LUS)-guided Lung Recruitment Maneuver (LRM) has been shown to possibly reduce ventilator-induced lung injury in preterm infants. However, to avoid potential hemodynamic and pulmonary side effects, the indication to perform the maneuver needs to be supported by early signs of lung recruitability. Recently, a new LUS pattern (S-pattern), obtained during the reopening of collapsed parenchyma, has been described. This study aims to evaluate if this novel LUS pattern is associated with a higher clinical impact of the LUS-guided LRMs. All the LUS-guided rescue LRMs performed on infants with oxygen saturation/fraction of inspired oxygen (S/F) ratio below 200, were included in this cohort study. The primary outcome was to determine if the presence of the S-pattern is associated with the success of LUS-guided recruitment, in terms of the difference between the final and initial S/F ratio (Delta S/F). We reported twenty-two LUS-guided recruitments, performed in nine patients with a median gestational age of 34 weeks, interquartile range (IQR) 28-35 weeks. The S-pattern could be obtained in 14 recruitments (64%) and appeared early during the procedure, after a median of 2 cmH2O (IQR 1-3) pressure increase. The presence of the S-pattern was significantly associated with the effectiveness of the maneuver as opposed to the cases in which the S-pattern could not be obtained (Delta S/F 110 +/- 47 vs 44 +/- 39, p = 0.01). Our results suggest that the presence of the S-pattern may be an early sign of lung recruitability, predicting LUS-guided recruitment appropriateness and efficacy.

Regular lung recruitment maneuvers during high-frequency oscillatory ventilation in extremely preterm infants: a randomized controlled trial

BackgroundLung 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.MethodsIn 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.ResultsFifteen 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.ConclusionRegular 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 registrationClinicalTrials.gov ID: NCT04289324 (28/02/2020).

Efficacy of recruitment manoeuvre with or without antiderecruitment strategy in ARDS patients: A prospective study

Introduction: Lung recruitment manoeuvre (RM) opens up collapsed segments of the ARDS lung but the collapse may reappear once the RM is complete and pre-RM positive end-expiratory pressure (PEEP) is applied. Aim: Evaluation of the outcome of setting PEEP using decrement PEEP titration (antiderecruitment manoeuvre - ADRM) after an alveolar recruitment manoeuvre (RM) in ARDS patients. Methods: Twenty four mechanically ventilated adult patients with ARDS were enrolled. This was a randomised, prospective study. After recording baseline parameters, on pressure control ventilation and stabilisation, RM was performed. The responders were randomly assigned to one of two groups: ‘Antiderecruitment RM’ (ADRM) group and ‘Only RM’ (RM) group. ADRM group received RM using volume control ventilation and optimal PEEP was set after RM using decremental PEEP titration method. The RM group patients were returned to baseline ventilator settings after manoeuvre. Results: Of the 24 patients, 13 were males and 11 female. The mean (± SD) age was 43 (± 13.43) years. Twelve patients responded to the initial recruitment manoeuvre of which six were assigned to RM group and six to ADRM group. There was no difference in survival rate between the groups. The ICU and hospital stay were shorter in patients in ADRM group as compared to only RM group. Conclusion: Only half of the patients with ARDS respond to recruitment manoeuvres with an improvement in oxygenation. In most responders, the improvement is sustained irrespective of whether RM only or ADRM was used. Mortality is high if the baseline P/F ratio is below 90.

Year in Review 2015: Recruitment manoeuvres in ARDS

Refractory hypoxaemia is a problem in patients with acute respiratory distress syndrome (ARDS). Although mechanical ventilation is the mainstay of management of ARDS, this therapy itself can cause damage to the lungs due to high tidal volume and high airway pressures. Lung protective strategies are used to reduce damage to the lungs due to mechanical ventilation. Use of small tidal volumes can cause alveolar derecruitment and arterial hypoxaemia. Lung recruitment manoeuvre (RM) opens up collapsed segments of the ARDS lung but the collapse may reappear once the RM is complete. Although RM has been shown to improve oxygenation there is still no clear data showing improvement in clinical outcome. This review summarises the different techniques used for RM, physiological effects of RM on lung mechanics along with monitoring RM at the bedside.

Shortened Automatic Lung Recruitment Maneuvers in an In Vivo Model of Neonatal ARDS.

The aim of this study was to assess the safety and efficacy of 2 protocols for automatic lung recruitment maneuvers (LRMs) using stepwise increases in PEEP in a neonatal ARDS model. These protocols were designed with lower maximum opening pressures than traditional methods and differ each one in the duration of the opening phases (short vs prolonged). We described hemodynamic changes through invasive monitoring, and we analyzed if the behavior of the variables depends on the duration of the opening phase of the LRM. We designed a prospective, experimental study with 10 Landrace x Large White pigs < 48 h old. Under general anesthesia, tracheal intubation, invasive hemodynamic monitoring with a pediatric arterial thermodilution catheter was performed. An ARDS model was developed with bronchoalveolar lavages. Two types of LRMs were performed in each piglet, with a maximum peak inspiratory pressure (PIP) of 30 cm H2O and a PEEP 15 cm H2O applied during 8.5 s in the short LRM and 17 s in the prolonged LRM. A comparative analysis by virtue of the Wilcoxon signed-rank test and a regression analysis using generalized estimation equation were performed. We found that both LRMs were effective regarding oxygenation and respiratory mechanics. Shortening the duration of the opening phase and lowering the maximum opening pressures to PIP 30 and PEEP 15 cm H2O were above the critical opening pressure to reverse alveolar collapse in our neonatal ARDS model. Although we observed hemodynamic variations during both types of LRMs, these were well tolerated. Our LRM protocols exceeded critical opening pressures to reverse alveolar collapse in our neonatal ARDS model. This range of pressures might involve less hemodynamic disturbance. Duration of the maximum opening pressure step is a determining factor for hemodynamic alterations.

Prone positioning may increase lung overdistension in COVID-19-induced ARDS

Real-time effects of changing body position and positive end-expiratory pressure (PEEP) on regional lung overdistension and collapse in individual patients remain largely unknown and not timely monitored. The aim of this study was to individualize PEEP in supine and prone body positions seeking to reduce lung collapse and overdistension in mechanically ventilated patients with coronavirus disease (COVID-19)-induced acute respiratory distress syndrome (ARDS). We hypothesized that prone positioning with bedside titrated PEEP would provide attenuation of both overdistension and collapse. In this prospective observational study, patients with COVID-19-induced ARDS under mechanical ventilation were included. We used electrical impedance tomography (EIT) with decremental PEEP titration algorithm (PEEPEIT-titration), which provides information on regional lung overdistension and collapse, along with global respiratory system compliance, to individualize PEEP and body position. PEEPEIT-titration in supine position followed by PEEPEIT-titration in prone position were performed. Immediately before each PEEPEIT-titration, the same lung recruitment maneuver was performed: 2 min of PEEP 24 cmH2O and driving pressure of 15 cmH2O. Forty-two PEEPEIT-titration were performed in ten patients (21 pairs supine and prone positions). We have found larger % of overdistension along the PEEP titration in prone than supine position (P = 0.042). A larger % of collapse along the PEEP titration was found in supine than prone position (P = 0.037). A smaller respiratory system compliance was found in prone than supine position (P < 0.0005). In patients with COVID-19-induced ARDS, prone body position, when compared with supine body position, decreased lung collapse at low PEEP levels, but increased lung overdistension at PEEP levels greater than 10 cm H2O.Trial registration number: NCT04460859.

Effect of electrical impedance-guided PEEP in reducing pulmonary complications after craniotomy: study protocol for a randomized controlled trial

ObjectiveThe purpose of this study is to explore whether electrical impedance tomography (EIT)-guided individualized positive end-expiratory pressure (PEEP) can reduce the incidence of pulmonary complications within 1 week following a craniotomy compared with a single PEEP (PEEP = 6 cmH2O) from dura suturing to extubation.MethodsA randomized controlled trial will be conducted at the Second Affiliated Hospital of Soochou University. Five hundred forty patients undergoing a craniotomy in the supine position will be randomly allocated into the P6 (PEEP = 6 cmH2O) or Pi (individualized PEEP) group. Both groups of patients will receive a lung recruitment maneuver before suturing the dura. Then, the P6 group will receive 6 cmH2O PEEP, and the Pi group will receive EIT-guided individualized PEEP. The incidence and severity score of pulmonary complications within 1 week following surgery, the lung ultrasound score (LUS), regional cerebral oxygen saturation (rScO2), and PaO2/FiO2 before anesthesia (T0), 10 min after extubation (T1), 24 h after extubation (T2), and 72 h after extubation (T3) will be compared between the two groups. The duration of surgery and anesthesia, the level and duration of PEEP during surgery, the volume of liquid intake and output during surgery, and the postoperative ICU and hospital stays will be recorded. The main outcome of this study will be the incidence of pulmonary complications within 1 week after surgery.DiscussionThe purposes of this study are to determine whether EIT-guided individualized PEEP from the beginning of dura suturing to extubation reduces the incidence of pulmonary complications within 1 week after a craniotomy compared with a single constant PEEP and to evaluate the length of ICU and hospital stays. If our results are positive, this study will show that EIT-guided individualized PEEP is better than a single constant PEEP and can further improve the prognosis of neurosurgical patients and reduce hospitalization costs, which will promote the wide application of individualized PEEP in clinical anesthesia.Trial registrationChinese Clinical Trial Registry CHiCTR2100051200. Registered on 15 September 2021.

Role of Lung Recruitment Maneuvers in Elderly Post-operative Upper Abdominal Surgery

Role of Lung Recruitment Maneuvers in Elderly Post-operative Upper Abdominal Surgery

Observation of Curative Effect of Lung Recruitment in Patients with Acute Respiratory Distress Syndrome after Cardiopulmonary Bypass Surgery.

Recruitment maneuver (RM) has become a routine supplementary maneuver for clinical rescue of severe ARDS with low tidal volume/pressure-limited mechanical ventilation. Recruitment of patients with ARDS mechanical ventilation can improve the lung compliance, promote the opening of collapsed alveoli, improve the ratio of ventilation to blood flow, reduce dead space, reduce shunt flow, and improve oxygenation function. In this paper, the patients were divided into lung recruitment group and conventional treatment group by the random number permutation table method. When the patient's percutaneous oxygen saturation is less than or equal to 88%, the partial pressure of oxygen in the arterial blood gas is less than or equal to 55 mmHg, or the ventilator tube is disconnected during sputum suction or other accidents, a CPAP × 60 − second lung recruitment maneuver is required. Then adjust the ventilator parameters in the same way. In the process of lung recruitment, the changes in invasive continuous arterial blood pressure will also be observed. If the blood pressure dropped to ≤90/60 mmHg, one recruitment maneuver was terminated in advance. And both groups of patients used the Dräger- or PB840-imported multifunctional ventilator. The treatment of primary disease and predisposing factors, fluid management strategies, antibiotics and glucocorticoids, nutrition, and metabolic support in the two groups of patients in the study were the same. The PaO2/FiO2 value improved by 51% 10 minutes after recruitment, and the median increased from 111 (IQR, 73-265) before recruitment to 170 (IQR, 102-340) (P < 0.01), the improvement of PaO2/FiO2 at 4 hours after recruitment and 12 hours after recruitment was 78% (P < 0.05) and 39% (P < 0.01), respectively, and the median PaO2/FiO2 at 4 hours after recruitment was 198 (IQR, 116-256). The median PaO2/FiO2 became 155 (IQR, 127-235) 12 hours after recruitment. Recruitment can reduce the accumulation of neutrophils in lung tissue, reduce the release of inflammatory factors, reduce pulmonary edema, and reduce pathological damage.