Inspiratory Positive Pressure Research Articles

Prognostic value of the oxygenation index measured during mechanical ventilation and weaning. A retrospective cohort study.

The aim of this study was to investigate the predictive value of the ratio of oxygen saturation (ROX) index calculated during mechanical ventilation (MV) and the weaning period in evaluating readiness to weaning and the success of the spontaneous breathing trial (SBT), extubation, and mortality. We also compared the results of the ROX index calculated with partial arterial oxygen pressure (PaO2), arterial oxygen saturation (SaO2%), and probe oxygen saturation (SpO2%). In this retrospective cohort study, the ROX index was calculated by SpO2%, PaO2, and SaO2% separately using the ROX index formula (PaO2 or SaO2 or SpO2 /FiO2)/respiratory rate. ROX was calculated during the first three days of MV treatment and the weaning period daily (SBT). Positive end-expiratory pressure and peak inspiratory pressure values were also recorded during these measurements. These ROX values were used to analyze whether they predict weaning readiness, SBT, extubation failure (EF), and mortality. The study included 107 mechanically ventilated patients. Weaning could be tried in 64 (60%) of the 107 patients; 44 (69%) of the 64 patients succeeded, and extubation was performed. 19 (43%) of 44 patients had EF. ROX values calculated with PaO2 during MV and SBT predicted readiness to wean, EF, and mortality better than ROX values calculated with SaO2 and SpO2. ROX values calculated with PaO2 during the third day of MV had the highest sensitivity and specificity for EF (sensitivity: 81%, specificity: 70% for the ROX<11 value). The results of this study suggest that the calculation of ROX index, not only with SpO2% but also with arterial blood gas PaO2 and SaO2% values, may be helpful in predicting the weaning readiness evaluation, SBT, and extubation success and mortality. Further studies with more patients are necessary to verify and standardize these results.

Comparison of a Valveless Trocar System and Conventional Insufflation in Pediatric Urologic Surgery.

Background: Conventional operative insufflation uses a one-way trocar to handle instruments while maintaining pneumoperitoneum. In 2007, the AirSeal® valveless trocar insufflation system was introduced, which maintains stable pneumoperitoneum while continuously evacuating smoke. Although this device has been validated in adult patients, it has not been extensively validated in the pediatric population. Materials and Methods: A retrospective cohort study of pediatric urology patients aged 0 to 21 who underwent laparoscopic pyeloplasty between March 2016 and October 2021 was performed. Intraoperative physiologic parameters, procedure characteristics, postoperative outcomes, and demographics of each patient in whom either AirSeal insufflation system (AIS) or conventional insufflation system (CIS) was utilized were obtained from hospital records. Data were compared across the AIS and CIS cohorts. The primary outcomes were intraoperative anesthetic and physiologic parameters, including end tidal carbon dioxide, oxygen saturation, body temperature, positive inspiratory pressure, systolic blood pressure, and heart rate. Results: There were no significant differences in the anesthetic and physiologic parameters in the AIS and CIS groups. In addition, no differences in demographics, procedural characteristics, or complication rates were found between the cohorts. Conclusion: The AirSeal valveless trocar insufflation system demonstrates comparable intraoperative anesthetic and physiologic outcomes compared to conventional one-way valve insufflation in pediatric laparoscopic pyeloplasty. Certain surgeon-related qualitative metrics are underappreciated in this study, however, including improved visualization with vigorous suctioning and pressure maintenance with frequent instrument exchanges. Surgeon experience may mask the benefits of these characteristics as it pertains to quantitative surgical outcomes such as estimated blood loss, operative time, and perioperative complications.

Pediatric Ventilation Liberation: A Survey of International Practice Among 555 Pediatric Intensivists.

IMPORTANCE:Pediatric ventilation liberation has limited evidence, likely resulting in wide practice variation. To inform future work, practice patterns must first be described.OBJECTIVES:Describe international pediatric ventilation liberation practices and regional practice variation.DESIGN, SETTING, AND PARTICIPANTS:International cross-sectional electronic survey. Nontrainee pediatric medical and cardiac critical care physicians.MAIN OUTCOMES AND MEASURES:Practices focusing on spontaneous breathing trial (SBT) eligibility, SBT practice, non-SBT extubation readiness bundle elements, and post-extubation respiratory support.RESULTS:Five-hundred fifty-five responses representing 47 countries were analyzed. Most respondents reported weaning followed by an SBT (86.4%). The top SBT eligibility variables reported were positive end-expiratory pressure (95%), Fio2 (93.4%), and peak inspiratory pressure (73.9%). Most reported use of standardized pressure support regardless of endotracheal tube size (40.4%) with +10 cm H2O predominating (38.6%). SBT durations included less than or equal to 30 minutes (34.8%), 31 minutes to 1 hour (39.3%), and greater than 1 hours (26%). In assigning an SBT result, top variables were respiratory rate (94%), oxygen saturation (89.3%), and subjective work of breathing (79.8%). Most reported frequent consideration of endotracheal secretion burden (81.3%), standardized pain/sedation measurement (72.8%), fluid balance (83%), and the endotracheal air leak test as a part of extubation readiness bundles. Most reported using planned high flow nasal cannula in less than or equal to 50% of extubations (83.2%). Top subpopulations supported with planned HFNC were those with chronic lung disease (67.3%), exposed to invasive ventilation greater than 14 days (66.6%), and chronic critical illness (44.9%). Most reported using planned noninvasive ventilation (NIV) following less than or equal to 20% of extubations (79.9%). Top subpopulations supported with planned NIV were those with neuromuscular disease (72.8%), chronic lung disease (66.7%), and chronic NIV use for any reason (61.6%). Regional variation was high for most practices studied.CONCLUSION AND RELEVANCE:International pediatric ventilation liberation practices are heterogeneous. Future study is needed to address key evidence gaps. Many practice differences were associated with respondent region, which must be considered in international study design.

Evaluation of adequacy of ventilation and gastric insufflation at three levels of inspiratory pressure for facemask ventilation during induction of anaesthesia: A randomised controlled trial

BackgroundIn this study, we aimed to compare three inspiratory pressures during facemask ventilation in paralysed patients regarding the subsequent incidence of gastric insufflation and the adequacy of lung ventilation. MethodsIn this randomised controlled trial, we included adult patients undergoing elective surgery under general anaesthesia. The patients were randomly allocated to receive positive inspiratory pressure (PIP) of 10, 15, or 20 cmH2O during pressure-controlled mask ventilation. Antral cross-sectional area (CSA) was assessed by ultrasound at baseline before mask ventilation and after endotracheal intubation and gastric insufflation was defined as increased CSA after endotracheal intubation > 30% of the baseline measurement. The primary outcome was the incidence of gastric insufflation. Other outcomes included the tidal volume, and the incidence of adequate ventilation (tidal volume of 6–10 mL/kg predicted body weight). ResultsWe analysed data from 36 patients in each group. The number of patients with gastric insufflation was the lowest in the PIP 10 group (0/36 [0%]) in comparison with PIP 15 (2/36 [19%] and PIP 20 36/36 [100%] groups (P-values of 0.019 and < 0.001, respectively). The probability of adequate ventilation at any time point was the highest in PIP 10, followed by PIP 15, and was the lowest in the PIP 20 group. ConclusionAn inspiratory pressure of 10 cmH2O in paralysed patients provided the least risk of gastric insufflation with adequate ventilation during induction of general anaesthesia compared to inspiratory pressure of 15- and 20 cmH2O.

A case of refractory pneumothorax and contralateral atelectasis after thoracoscopic subtotal esophagectomy treated with independent lung ventilation

BackgroundIndependent lung ventilation (ILV) allows separate positive end-expiratory pressures (PEEP) and inspiratory pressures for each lung. However, only a few articles have reported ILV management for lungs affected by different pathologies.Case presentationA 56-year-old man underwent video-assisted thoracic surgery for esophageal cancer. The right lung was injured during surgery, causing a bronchopleural fistula and necessitating chest drainage. On the third day in the intensive care unit, the patient’s oxygenation worsened during pressure support with continuous positive airway pressure ventilation. ILV was initiated for right-sided severe pneumothorax and left-sided atelectasis and pneumonia. ILV was continued for 2 days, and the patient’s trachea was successfully extubated the following day.ConclusionApplying high-level PEEP to the one lung and minimizing the airway pressure on the other lung could be achieved using ILV, which might contribute to successful tracheal extubation.

Mechanical Power during General Anesthesia and Postoperative Respiratory Failure: A Multicenter Retrospective Cohort Study.

Mechanical power during ventilation estimates the energy delivered to the respiratory system through integrating inspiratory pressures, tidal volume, and respiratory rate into a single value. It has been linked to lung injury and mortality in the acute respiratory distress syndrome, but little evidence exists regarding whether the concept relates to lung injury in patients with healthy lungs. This study hypothesized that higher mechanical power is associated with greater postoperative respiratory failure requiring reintubation in patients undergoing general anesthesia. In this multicenter, retrospective study, 230,767 elective, noncardiac adult surgical out- and inpatients undergoing general anesthesia between 2008 and 2018 at two academic hospital networks in Boston, Massachusetts, were included. The risk-adjusted association between the median intraoperative mechanical power, calculated from median values of tidal volume (Vt), respiratory rate (RR), positive end-expiratory pressure (PEEP), plateau pressure (Pplat), and peak inspiratory pressure (Ppeak), using the following formula: mechanical power (J/min) = 0.098 × RR × Vt × (PEEP + ½[Pplat - PEEP] + [Ppeak - Pplat]), and postoperative respiratory failure requiring reintubation within 7 days, was assessed. The median intraoperative mechanical power was 6.63 (interquartile range, 4.62 to 9.11) J/min. Postoperative respiratory failure occurred in 2,024 (0.9%) patients. The median (interquartile range) intraoperative mechanical power was higher in patients with postoperative respiratory failure than in patients without (7.67 [5.64 to 10.11] vs. 6.62 [4.62 to 9.10] J/min; P < 0.001). In adjusted analyses, a higher mechanical power was associated with greater odds of postoperative respiratory failure (adjusted odds ratio, 1.31 per 5 J/min increase; 95% CI, 1.21 to 1.42; P < 0.001). The association between mechanical power and postoperative respiratory failure was robust to additional adjustment for known drivers of ventilator-induced lung injury, including tidal volume, driving pressure, and respiratory rate, and driven by the dynamic elastic component (adjusted odds ratio, 1.35 per 5 J/min; 95% CI, 1.05 to 1.73; P = 0.02). Higher mechanical power during ventilation is statistically associated with a greater risk of postoperative respiratory failure requiring reintubation.

Неинвазивная вентиляция легких (лекция)

В лекции освещены вопросы step by step респираторной терапии у больных с острой дыхательной дисфункцией (ОДД). Первым шагом в лечении больных с ОДД (при отсутствии показаний к инвазивной механической вентиляции легких) является использование высокопоточной оксигенации (ВПО) и неинвазивной вентиляции легких (НИВЛ). По сравнению с инвазивной механической вентиляцией легких эти технологии имеют определенные преимущества. Они не приводят к вентилятор-ассоциированному повреждению легких, вентилятор-ассоциированной диафрагмальной дисфункции и не вызывают вентилятор-ассоциированной пневмонии. НИВЛ обеспечивает определенная концентрация кислорода на вдохе (FiO2) в сочетании с умеренным давлением в конце выдоха (РЕЕР)/постоянным положительным давлением в дыхательных путях (СРАР) и инспираторным давлением. В отличие от оксигенации через лицевую маску или носовые канюли она уменьшает возможность экспираторного закрытия мелких дыхательных путей, предупреждает коллапс альвеол и возможность возникновения ателектазов. Преимуществом НИВЛ в сравнении со стандартной оксигенотерапией через лицевую маску/носовые канюли можно считать то, что она обеспечивает умеренный уровень РЕЕР/СРАР, который уменьшает пред- и постнагрузку левого желудочка. Это имеет особенное значение у больных с острой левожелудочковой недостаточностью или отеком легких. Главным условием успешного проведения НИВЛ является наличие адекватного сознания у больного. В основе клинической эффективности ВПО лежит возможность создания большой скорости потока газа (до 60 л/мин). Такая скорость потока (которая равна или даже больше скорости потока при вдохе больного) минимизирует «примешивание» комнатного воздуха и разрешает поддерживать на вдохе высокую FiO2. Принципиально важно наличие возможности методом step by step регулировать скорость потока и температуры, точное измерение FiO2. Современные системы ВПО имеют специальные контуры из полупроницаемых материалов, которые не допускают образования конденсата и имеют оригинальные носовые или трахеостомические канюли.

Sleep increases leaks and asynchronies during home noninvasive ventilation: a polysomnographic study.

In patients treated with noninvasive ventilation, sleep-related breathing changes can modify patient-ventilator interactions, which could reduce its effectiveness. The aim of this prospective observational study was to determine the impact of sleep/wake state on leaks, upper airway obstructive events, and asynchronies in patients treated by long-term noninvasive ventilation. Stable patients adapted to noninvasive ventilation were considered for nocturnal polysomnography. Unintentional leaks, upper airway obstructive events, and asynchronies were compared between sleep and awake periods. Twenty-eight patients were enrolled. Underlying diagnoses were neuromuscular disease (n = 11), chest wall disease (n = 8), and obesity-hypoventilation (n = 9). Leaks were more frequent in sleep than in awake periods, with a median of 10% (interquartile range [IQR], 0%-75%) vs 1% (IQR, 0%-9%) of time (P < .001), respectively. During sleep, asynchronies with and without associated leak affected 27% of breaths (IQR, 16%-39%) compared with non-leak-related asynchronies that were recorded in 8% (IQR, 3%-25%) of breaths (P < .001). Asynchronies affecting more than 10% of total breaths were more frequent in sleep (25 patients, 89%) than in awake time (8 patients, 29%; P = .25). Eleven patients (39%) presented with 5 or more upper airway obstructive events without reduction in ventilatory drive per hour of sleep. In patients adapted to home noninvasive ventilation, leaks, asynchronies, and upper airway obstructive events are frequent during the night and are concentrated in sleep periods. Asynchronies are often associated with leaks. These findings may have clinical implications considering that in patients with low sleep efficiency respiratory events could be underestimated if sleep is not evaluated. Martí S, Ferré A, Sampol G, etal. Sleep increases leaks and asynchronies during home noninvasive ventilation: a polysomnographic study. J Clin Sleep Med. 2022;18(1):225-233.

Efficacy of a Novel Medical Adhesive for Sealing Lung Parenchyma: An in vitro Study in Rabbit Lungs

Introduction: During thoracic resection procedures, complete hemostasis and aerostasis are priorities. A persistent alveolar air leak is associated with increased morbidity and mortality rates. This study aimed to evaluate whether the novel medical adhesive VIVO (Adhesys Medical GmbH Aachen, Germany) is a reliable alternative sealing technique to routine surgical procedures. Methods: We conducted an in vitro animal study by analyzing 21 lungs of New Zealand (n = 19) and Chinchilla Bastard (n = 2) rabbits (age, 11–18 weeks; weight, 2,400–3,600 g). Three groups, each comprising 7 animals, were evaluated. VIVO (VIVO-group) was compared with standard surgical lung parenchymal lesion closure with a polypropylene suture (Suture-group) and TachoSil® (TachoSil-group). We adopted a stable, pressure-controlled ventilation protocol. After explantation, a surgical incision 0.5-cm deep and 1.5-cm wide was made in the lungs using a customized template. Air leak was measured quantitatively (mL/min) using a respirator and visualized qualitatively by 2 observers who made independent judgments. Next, the leak was closed using VIVO, suture, or TachoSil® as specified by the manufacturer. Subsequently, positive end-expiratory pressure (PEEP) and inspiratory pressure were gradually increased until a maximum of 15 and 30 mbar were attained, respectively. Results: At PEEPs of 8, 10, and 15 mbar, VIVO achieved complete sealing of the profound parenchymal defect in all (n = 7) lungs. After closure of the incision, we observed an air leak variation of 127 ± 114 mL/min (Suture-group), 31 ± 49 mL/min (VIVO-group), and 114 ± 134 mL/min (TachoSil-group). VIVO showed a significantly lower air leak than surgical sutures (p = 0.031) and TachoSil® (p = 0.046). Conclusion: VIVO offers sufficient closure of the lung parenchymal lesions. The novel adhesive enabled significantly better sealing with lower persistent air leakage than TachoSil® or surgical sutures. Further investigation using in vivo models is strongly encouraged to confirm our findings.

Heart-Protective Mechanical Ventilation in Postoperative Cardiosurgical Patients.

Background This study compared the hemodynamic effects and gas exchange under several different ventilator settings—with regard to tidal volume, respiratory rate, and end-expiratory pressure—in patients after coronary artery bypass grafting (CABG). Methods Prospective interventional cohort study with a controlled group in a single cardiosurgical ICU involving 119 patients following on-pump CABG surgery. During the 1st postoperative hour, the intervention group patients were ventilated with Vt 10 ml × kg−1, RR 14/min, PEEP 5 cmH2O (“conventional ventilation”). During the 2nd hour, RR was reduced to 8/min (“reduced RR ventilation”). At 3 hrs, Vt was decreased to 6 ml × kg−1, RR returned to 14/min, and PEEP increased to 10 cmH2O (“low Vt-high PEEP ventilation”). Results Patients in the “low Vt-high PEEP” ventilation period showed significantly lower alveolar ventilation and thoraco-pulmonary compliance than during “reduced RR” ventilation. Mean airway pressure and Vds/Vt peaked during low Vt-high PEEP ventilation; however, driving pressure was lower. Vt decrease and PEEP increase did not lead to oxygenation improvement and worsened CO2 elimination. Hemodynamically, the study revealed significant cardiac output decrease during low Vt-high PEEP ventilation. In 23.2% of patients, catecholamine therapy was initiated. Conclusions In postoperative cardiosurgical patients, MV with Vt 6 ml × kg−1 and PEEP 10 cm H2O is characterized by worsened oxygenation and elimination of CO2 and a less favorable hemodynamic profile than ventilation with Vt 10 ml × kg−1 and PEEP 5 cmH2O. New and Noteworthy. (i) Patients after CABG may be especially sensitive to low tidal volume and increased PEEP as it negatively affects hemodynamic profile by means of the right heart preload decrease and afterload increase. (ii) Mechanical ventilation settings aiming to minimize mean airway pressure reduce the negative effects of positive inspiratory pressure and are favorable for hemodynamics.

Ex Vivo Perfusion With Methylprednisolone Attenuates Brain Death-induced Lung Injury in Rats

Background.The onset of brain death (BD) leads to the deterioration of potential donor lungs. Methylprednisolone is considered to increase lung oxygenation capacity and enhance the procurement yield of donor lungs, when applied in situ, during donor management. However, whether BD-induced lung damage is ameliorated upon treatment with methylprednisolone during acellular ex vivo lung perfusion (EVLP), remains unknown. We aimed to investigate whether the quality of lungs from brain-dead donors improves upon methylprednisolone treatment during EVLP.Methods.Rat lungs were randomly assigned to 1 of 3 experimental groups (n = 8/group): (1) healthy, directly procured lungs subjected to EVLP; (2) lungs from brain-dead rats subjected to cold storage and EVLP; and (3) lungs from brain-dead rats subjected to cold storage and EVLP with 40 mg methylprednisolone added to the perfusate. Ventilation and perfusion parameters, histology, edema formation, metabolic profile, and inflammatory status of lungs were investigated.Results.Methylprednisolone treated lungs from brain-dead donors improved positive inspiratory pressures needed to maintain tidal volumes of 7 mL/kg of body weight, which was 25.6 ± 5.8 cm H2O in untreated lungs and 18.0 ± 3.0 cm H2O in methylprednisolone treated lungs, after 6 h EVLP. Furthermore, dynamic lung compliance increased upon methylprednisolone treatment, with values of 0.11 ± 0.05 mL/cm H2O versus 0.18 ± 0.04 mL/cm H2O after 6 h of EVLP. Methylprednisolone treatment ameliorated the amount of lung edema, as corroborated by a reduction of 0.7 in the wet/dry ratio. Although glucose consumption levels were comparable, the BD-induced cumulative lactate production decreased from 0.44 ± 0.26 to 0.11 ± 0.16 mmol/L upon methylprednisolone treatment. Finally, BD-induced inflammatory status was reduced upon methylprednisolone treatment compared to untreated lungs from brain-dead donors, as reflected by lower proinflammatory gene expression levels of IL-1β, IL-6 and MCP-1, and IL-6 perfusate levels.Conclusions.We showed that methylprednisolone treatment during EVLP attenuates BD-induced lung injury.

Airway Resistance and Respiratory Compliance in Children with Acute Viral Bronchiolitis Requiring Mechanical Ventilation Support.

BackgroundAcute viral bronchiolitis (AVB) is a very frequent disease that affects the lower airways of young children increasing the inspiratory and expiratory resistance in variable degree as well as reducing the pulmonary compliance. It would be desirable to know whether these variables are associated with the outcome.ObjectivesTo evaluate the respiratory mechanics in infants with AVB requiring mechanical ventilation (MV) support and to evaluate if respiratory mechanics predict outcomes in children with AVB supported on MV. To evaluate the respiratory mechanics in infants with AVB submitted to MV.Materials and methodsA prospective observational study was conducted in two pediatric intensive care units (PICUs) between February 2016 and March 2017. Included were infants (1 month to 1 year old) admitted with AVB and requiring MV for >48 hours. Auto-PEEP, dynamic compliance (Cdyn), static compliance (Cstat), expiratory resistance (ExRes), and inspiratory resistance (InRes) were evaluated once daily on the second and third day of MV.ResultsA total of 64 infants (median age of 2.8 months and a mean weight of 4.8 ± 1.7 kg) were evaluated. A mean positive inspiratory pressure (PIP) of 31.5 ± 5.2 cmH2O, positive end-expiratory pressure (PEEP) of 5.5 ± 1.4 cmH2O, resulting in a mean airway pressure (MAP) of 12.5 ± 2.2 cmH2O and delta pressure of 22.5 ± 4.4 cmH2O without difference between the two hospitals. Measurements of respiratory mechanics showed high values of InRes and ExRes (median 142 [IQ25–75 106–180] cmH2O/L/s and 158 [IQ25–75 130–195.3] cmH2O/L/s, respectively), accompanied by decreased Cdyn and Cstat (0.46 ± 0.19 and 0.81 ± 0.25 mL/kg/cmH2O, respectively). None of the variables was associated with mortality, length of MV, or length of PICU stay.ConclusionInfants with AVB requiring MV support present very high InRes and ExRes values. These findings might be the reason for the aggressive ventilatory parameters, especially PIP, required to ventilate this group of children with lower airway obstruction.Clinical significanceMonitoring respiratory mechanics could represent a useful tool to guide the ventilatory strategy to be adopted in patients with AVB.How to cite this articleAndreolio C, Piva JP, Bruno F, da Rocha TS, Garcia PCR. Airway Resistance and Respiratory Compliance in Children with Acute Viral Bronchiolitis Requiring Mechanical Ventilation Support. Indian J Crit Care Med 2021;25(1):88–93.

Noninvasive ventilatory support in morbid obesity

BackgroundIn the conventional management of the morbidly obese that normalizes the apnea-hypopnea index (AHI), CO2 levels often remain elevated. MethodsA retrospective review of morbidly obese patients using volume preset settings up to 1800ml to positive inspiratory pressures (PIPs) of 25–55cm H2O, or pressure control at 25–50cm H2O pressure via noninvasive interfaces up to continuously (CNVS). ResultsTwenty-six patients, mean 55.6±14.8 years of age, weight 108–229kg, mean BMI 56.1 (35.5–77)kg/m2, mean AHI 69.0±24.9, depended on up to CNVS for 3 weeks to up to 66 years. There were eleven extubations and seven decannulations to CNVS despite failure to pass spontaneous breathing trials. Thirteen were CNVS dependent for 92.2 patient-years with little to no ventilator free breathing ability (VFBA). Six used NVS from 10 to 23h a day, and others only for sleep. Fifteen patients with cough peak flows (CPF) less than 270L/m had access to mechanical insufflation-exsufflation (MIE) in the peri-extubation/decannulation period and long-term. The daytime end-tidal (Et)CO2 of 14 who were placed on sleep NVS without extubation or decannulation to it decreased from mean EtCO2 61.0±9.3–38.5±3.6mm Hg and AHI normalized to 2.2. Blood gas levels were normal while using NVS/CNVS. Pre-intubation PaCO2 levels, when measured, were as high as 183mm Hg before extubation to CNVS. ConclusionsVentilator unweanable morbidly obese patients can be safely extubated/decannulated and maintained indefinitely using up to CNVS rather than resort to tracheotomies.

DESIGN AND DEVELOPMENT OF MOBILE OPERATED PORTABLE VENTILATOR.

This paper describes the concept of full function portable ventilator, which have low cost, minimum weight, compact, small-sized. It can easily operate by mobile application and that application able to measure PEEP pressure, tidal volume and flow rate. The essential components used are stepper motor, rack and pinion, motor driver, Nod MCU, Acrylic sheet, Battery etc. There are some open sources Hardware ventilator (OSM-MVs) have been used during COVID-19 Pandemic. The ventilator device breaths by compressing a convention bag-valve mask (BVM) with a help of Rack and Pinion, that eliminate the need of human operator for the BVM. Initially the prototype is built out by Acrylic Sheets, it is work as thermal insulator and it's approximately 20% better than glass. The measurement of portable ventilator is 9.8*4.7*7 inches (250*120*180) mm and weighting 2.20lbs (1.5kg). It is driven by the motor driver powered by a VDC battery. The sensors are used to operate it by a mobile operation for measurement of tidal volume, PEEP pressure etc. The design is made up of CAD software and also makes Ansys for this device. The experimental results taking after testing on artificial lung that where the Positive Inspiratory Pressure (PIP), respiratory rate (RR), tidal volume, Positive end- expiratory pressure (PEEP) and its accuracy exceeding human capabilities in BVM.

Novel modes of non-invasive ventilation in chronic respiratory failure: a narrative review.

Home non-invasive ventilation (NIV) is central in the management of chronic hypercapnic respiratory failure and is associated with improvements in clinically relevant outcomes. Home NIV typically involves delivery of fixed positive inspiratory and expiratory airway pressures. These pressures do not reflect physiological changes to respiratory mechanics and airway calibre during sleep, which may impact on physiological efficacy, subsequent clinical outcomes, and therapy adherence. Novel ventilator modes have been designed in an attempt to address these issues. Volume-assured pressure support modes aim to automatically adjust inspiratory pressure to achieve a pre-set target tidal volume. The addition of auto-titrating expiratory pressure to maintain upper airway calibre is designed for patients at risk of upper airway collapse, such as obese patients and those with obstructive sleep apnoea complicating their hypercapnic failure. Heterogeneity in setup protocols, patient selection and trial design limit firm conclusions to be drawn on the clinical efficacy of these modes. However, there are data to suggest that compared to fixed-pressure NIV, volume-assured modes may improve nocturnal carbon dioxide, sleep quality and ventilator adherence in select patients. The use of the forced oscillation technique to identify expiratory flow limitation and adjust expiratory pressure to eliminate it is the most recent addition to these advanced modes and is yet to be assessed in formal clinical trials.

Early signs of right ventricular systolic and diastolic dysfunction in acute severe respiratory failure: the importance of diastolic restrictive pattern.

Background:The incidence and pathophysiology of right ventricular failure in patients with severe respiratory insufficiency has been largely investigated. However, there is a lack of early signs suggesting right ventricular systolic and diastolic dysfunction prior to acute cor pulmonale development.Methods:We conducted a retrospective analytical cohort study of patients for acute respiratory distress syndrome undertaking an echocardiography during admission in the cardiothoracic intensive care unit. Patients were divided according to treatment: conventional protective ventilation (38 patients, 38%); interventional lung assist (23 patients, 23%); veno-venous extracorporeal membrane oxygenation (37 patients, 37%). Systolic and diastolic function was studied assessing, respectively: right ventricular systolic longitudinal function (tricuspid annular plane systolic excursion) and systolic contraction duration (tricuspid annular plane systolic excursion length); right ventricular diastolic filling time and right ventricular diastolic restrictive pattern (presence of pulmonary valve presystolic ejection wave). Correlation between the respiratory mechanics and systo-diastolic parameters were analysed.Results:In 98 patients studied, systolic dysfunction (tricuspid annular plane systolic excursion <16 mm) was present in 33.6% while diastolic restrictive pattern was present in 64%. A negative correlation was found between tricuspid annular plane systolic excursion and tricuspid annular plane systolic excursion length (P<0.0001; r −0.42). Tricuspid annular plane systolic excursion and tricuspid annular plane systolic excursion length correlated with right ventricular diastolic filling time (P<0.001; r −0.39). Pulmonary valve presystolic ejection wave was associated with tricuspid annular plane systolic excursion (P<0.0001), tricuspid annular plane systolic excursion length (P<0.0001), right ventricular diastolic filling time (P<0.0001), positive end-expiratory pressure (P<0.0001) and peak inspiratory pressure (P<0.0001).Conclusion:Diastolic restrictive pattern is present in a remarkable percentage of patients with respiratory distress syndrome. Bedside echocardiography allows a mechanistic evaluation of systolic and diastolic interaction of the right ventricle.

Cardiovascular surgery complication and the benefits of pulmonary rehabilitation in preventing COPD exacerbation

Introduction. Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide, and the burden of the disease is constantly increasing. Although COPD is primarily characterized by the presence of airflow obstruction, in many patients, it is associated with systemic manifestations that can result in impaired functional capacity, reduced quality of life, and increased mortality. Pulmonary rehabilitation (PR) consists of a multidisciplinary and comprehensive non-pharmacological intervention that is designed to improve health status in COPD patients, along with pharmacologic treatment. PR has also been shown to improve the diaphragmatic mobility in patients with different conditions that affect the diaphragm. The aim of the paper is to describe the clinical and functional features of a COPD patient with unilateral paralysis of the phrenic nerve and the role of PR as a major component of the case management. Material and method. This paper presents the case of a 66-year-old patient, diagnosed with COPD Gold stage III, which suffered a surgical intervention for an aorta aneurysm and later complicated with phrenic nerve injury and left diaphragmatic paralysis. This condition worsened the respiratory functional status and the patient needed a tailored treatment. Results and discussions. The treatment included besides inhaled dual long acting bronchodilator and corticoid therapy, pulmonary rehabilitation with complex methods, consisting in training of the respiratory musculature and techniques of bronchial drainage using devices with positive inspiratory and expiratory pressure, with good clinical and functional outcomes. A PR program should be included into a personalized management plan, along with pharmacological therapy. Conclusion. Although there is no standard treatment for COPD associated with unilateral paralysis of the phrenic nerve, it is important to diagnose these conditions promptly, and to recommend the adequate pharmacological treatment for controlling the symptoms along with a personalized complex respiratory rehabilitation program, in order to increase functional status and quality of life. Key words: respiratory rehabilitation, COPD, phrenic nerve paralysis

Quantitative rise in intraocular pressure in patients undergoing robotic surgery in steep Trendelenburg position: A prospective observational study.

Background and Aims:Raised intraocular pressure (IOP) is one of the known causes of anterior ischemic optic neuropathy. In the case of robotic urological-gynecological surgeries, patient is kept in steep Trendelenburg supine-lithotomy position. Aim of this study was to observe the quantitative rise in IOP in steep Trendelenburg position (>45°) in robotic-assisted prostatectomy and hysterectomy.Material and Methods:After institutional ethical clearance and written informed consent, 100 patients undergoing robotic surgeries in steep Trendelenburg position were recruited for the study. IOP was measured at different time intervals in steep Trendelenburg position using Schiotz tonometer: Post intubation (T1), post pneumoperitoneum (T2), post steep Trendelenburg (T3), and rest readings were taken 30 min apart. T9 was taken 10 min after patient is made supine and parallel to the ground. Mean arterial pressure (MAP), positive inspiratory pressure (PIP), and end-tidal carbon dioxide (EtCO2) values were recorded at different time points. Descriptive analysis, linear regression analysis, and Freidman's nonparametric tests were used to analyze the results.Results:Ninety-five patients were included for statistical analysis as five patients were excluded due to intraoperative interventions leading to alteration of results. Mean IOP at T1 was 19.181/18.462 mmHg in L/R eye. A gradual rise in IOP was observed with every time point while patient was in steep Trendelenburg position which reverts back to near normal values once the patient is changed to normal position 21.419/20.671: Left/right eye in mm of Hg. Uni and multiple regression analysis showed insignificant P value, thus no correlation between MAP, PIP, and EtCO2 with IOP.Conclusion:Steep Trendelenburg position for prolong duration leads to significant rise in intraocular pressure.

Mechanical Ventilation Guided by Electrical Impedance Tomography in Children With Acute Lung Injury.

To provide proof-of-concept for a protocol applying a strategy of personalized mechanical ventilation in children with acute respiratory distress syndrome. Positive end-expiratory pressure and inspiratory pressure settings were optimized using real-time electrical impedance tomography aiming to maximize lung recruitment while minimizing lung overdistension. Prospective interventional trial. Two PICUs. Eight children with early acute respiratory distress syndrome (< 72 hr). On 3 consecutive days, electrical impedance tomography-guided positive end-expiratory pressure titration was performed by using regional compliance analysis. The Acute Respiratory Distress Network high/low positive end-expiratory pressure tables were used as patient's safety guardrails. Driving pressure was maintained constant. Algorithm includes the following: 1) recruitment of atelectasis: increasing positive end-expiratory pressure in steps of 4 mbar; 2) reduction of overdistension: decreasing positive end-expiratory pressure in steps of 2 mbar until electrical impedance tomography shows collapse; and 3) maintaining current positive end-expiratory pressure and check regional compliance every hour. In case of derecruitment start at step 1. Lung areas classified by electrical impedance tomography as collapsed or overdistended were changed on average by -9.1% (95% CI, -13.7 to -4.4; p < 0.001) during titration. Collapse was changed by -9.9% (95% CI, -15.3 to -4.5; p < 0.001), while overdistension did not increase significantly (0.8%; 95% CI, -2.9 to 4.5; p = 0.650). A mean increase of the positive end-expiratory pressure level (1.4 mbar; 95% CI, 0.6-2.2; p = 0.008) occurred after titration. Global respiratory system compliance and gas exchange improved (global respiratory system compliance: 1.3 mL/mbar, 95% CI [-0.3 to 3.0], p = 0.026; Pao2: 17.6 mm Hg, 95% CI [7.8-27.5], p = 0.0039; and Pao2/Fio2 ratio: 55.2 mm Hg, 95% CI [27.3-83.2], p < 0.001, all values are change in pre vs post). Electrical impedance tomography-guided positive end-expiratory pressure titration reduced regional lung collapse without significant increase of overdistension, while improving global compliance and gas exchange in children with acute respiratory distress syndrome.

Efeitos da pressão positiva contínua e de dois níveis na via aérea em edema agudo de pulmão cardiogênico: uma revisão sistemática

INTRODUÇÃO: O edema agudo de pulmão cardiogênico (EAPC) representa uma importante causa de insuficiência respiratória aguda podendo ser atenuada com a instalação de ventilação mecânica não-invasiva (VNI). OBJETIVO: Comparar pressão positiva contínua (CPAP) e pressão positiva de dois níveis (BIPAP) na via aérea em pacientes adultos com EAPC, quanto à função pulmonar, ao tempo de permanência, suas complicações e a dispneia através de uma revisão sistemática. METODOLOGIA: Ensaios clínicos controlados e randomizados (ECR), revisados por dois revisores independentes, conforme recomendações PRISMA, nas bases de dados PubMed e Biblioteca Cochrane. Incluídos estudos originais que utilizaram a CPAP e a BIPAP em pacientes com EAPC publicados na língua inglesa. A Escala PEDro foi utilizada para analisar a qualidade metodológica dos estudos e a Cochrane Collaboration para análise de risco de viés. RESULTADOS: Foram incluídos 13 artigos, publicados entre os anos 1997 e 2014. Os níveis de CPAP variaram entre 5 e 20 cmH2O nos estudos, e BIPAP apresentou-se com pressão inspiratória positiva (IPAP) entre 8 e 20 cmH2O e pressão expiratória positiva (PEEP) entre 3 e 10 cmH2O. Os estudos apresentaram CPAP e BIPAP sem diferença estatisticamente significante para a melhora da função pulmonar (FR, PaO2 e PaCO2), tempo de internamento, taxas de mortalidade, entubação e infarto agudo do miocárdio (IAM); mostrando-se como modalidades igualmente eficazes. CONCLUSÃO: CPAP e a BIPAP garantem os mesmos efeitos para melhora da função pulmonar, não mantém relação com a permanência da internação e complicações, e melhoram o quadro de dispneia.