PEEP Levels Research Articles

ICU tracheotomies in patients with COVID-19: a lesson learned for future viral pandemic

IntroductionThe coronavirus SARS-CoV-2 pandemic has resulted in a large number of patients requiring intubation and prolonged mechanical ventilation. The current knowledge on the tracheotomies regarding the time form intubation, method and ventilatory parameters optimal for their performance in the mechanically ventilated patients with COVID ARDS are scarce; thus, the aim of this study is to present new data regarding their safety, adverse events and timing.Materials and methodsThis retrospective observational study is based on the data of 66 critically ill COVID patients including demographic data, timing and technique of tracheotomy, ventilatory parameters in the time of procedure, as well as complication and survival rate.ResultsA number of 66 patients with COVID-related pneumonia were included in the study, among whom 32 were tracheotomized—25 patients underwent an early tracheotomy and 7 patients had late tracheotomy. The median duration of mechanical ventilation before the tracheotomy in the early group was 8 days (IQR 6–10) compared to 11 days (IQR 11–12.5.) p < 0.001) in late group. Risk of death in tracheotomy patients was significantly growing with growing level of PEEP and FiO2 at the moment of decision on tracheotomy, OR = 1.91 CI95 (1.23;3.57); p = 0.014 and OR = 1.18 CI95(1.03;1.43); p = 0.048, respectively.ConclusionEarly percutaneous tracheotomy is safe (both in terms of risk of viral transmission and complication rate) and feasible in COVID-19 patients. Stability of gas exchange, and ventilatory parameters are the main prognostic factors of the outcome.

Ventilator management using esophageal balloon pressure measurements

Mechanical ventilation provides essential support for patients with acute respiratory failure and provides time for these patients to recover from the primary disorder. Ventilator strategies need to provide adequate oxygenation and avoid barotrauma. This trauma develops when some regions of the lungs are overinflated and develops when some regions are underinflated and have cyclical opening and closing during the respiratory cycle. The ARDS network trial demonstrated that a low tidal volume and low pressure strategy improved outcomes. Subsequent trials have tried to determine the optimal PEEP level in patients with moderate to severe ARDS. The use of esophageal balloons provides information about the transpulmonary pressure at the end of inspiration and the transpulmonary pressure at the end of expiration. However, available studies to date do not demonstrate a definite improvement in outcomes in patients with ventilator adjustments based on esophageal pressures. Beitler et al. randomized 200 patients with moderate to severe ARDS into one group in which PEEP titration was based on esophageal balloon pressure measurements, and a second group in which PEEP titration was based on a high FiO2/PEEP table studied in earlier trials. There were no differences in mortality between the two groups. Reanalysis of this information after the trial was completed suggested that transpulmonary pressures in the range of -2 to + 2 cm H2O at the end of expiration were associated with improved outcomes compared to pressures outside that range.

Performance Characteristics of a Novel 3D-Printed Bubble Intermittent Mandatory Ventilator (B-IMV) for Adult Pulmonary Support.

The COVID-19 pandemic has brought attention to the need for developing effective respiratory support that can be rapidly implemented during critical surge capacity scenarios in healthcare settings. Lung support with bubble continuous positive airway pressure (B-CPAP) is a well-established therapeutic approach for supporting neonatal patients. However, the effectiveness of B-CPAP in larger pediatric and adult patients has not been addressed. Using similar principles of B-CPAP pressure generation, application of intermittent positive pressure inflations above CPAP could support gas exchange and high work of breathing levels in larger patients experiencing more severe forms of respiratory failure. This report describes the design and performance characteristics of the BubbleVent, a novel 3D-printed valve system that combined with commonly found tubes, hoses, and connectors can provide intermittent mandatory ventilation (IMV) suitable for adult mechanical ventilation without direct electrification. Testing of the BubbleVent was performed on a passive adult test lung model and compared with a critical care ventilator commonly used in tertiary care centers. The BubbleVent was shown to deliver stable PIP and PEEP levels, as well as timing control of breath delivery that was comparable with a critical care ventilator.

Positive versus negative pressure during removal of endotracheal-tube on prevention of post-extubation atelectasis in ventilated neonates: A randomized controlled trial

BackgroundPost-extubation-atelectasis (PEA) is a common problem after the removal of an endotracheal tube in neonates which increases the rate of extubation failure. Different techniques have been introduced for the prevention of PEA. One technique is the removal of the endotracheal tube by negative or positive gradients of pressure. No RCT has yet been done to compare the use of these two methods in neonates. So this study aimed to compare the role of positive and negative pressure during extubation of neonates on the prevention of PEA. Materials and methodsWe enrolled 100 newborns in this RCT that required at least 24 h of mechanical ventilation. The endotracheal tube in one group was removed by a T-Piece resuscitator at a PEEP level of 5 CmH2o while in another group extubation was done applying suction pressure of 100 mmHg by random selection. Prevalence of PEA in CXRs after extubation was compared between the two groups. ResultsThe prevalence of PEA in the extubation of the positive pressure group (24%) was significantly lower than that of the negative pressure group (46%) (p = 0.024). Extubation failure was found to be lower in the positive pressure group (6% versus 20% P = 0.037). No significant difference was observed between the two groups in the prevalence of apnea, pneumothorax, and death at 3 days after extubation. ConclusionThe use of positive pressure during removal of the endotracheal tube in newborn infants reduced the rate of PEA compared with the negative pressure so extubation by a positive pressure is recommended in neonates.

Clinical characteristics, respiratory management, and determinants of oxygenation in COVID-19 ARDS: A prospective cohort study.

PurposeTo identify determinants of oxygenation over time in patients with COVID-19 acute respiratory distress syndrome (ARDS); and to analyze their characteristics according to Berlin definition categories.Materials and methodsProspective cohort study including consecutive mechanically ventilated patients admitted between 3/20/2020–10/31/2020 with ARDS. Epidemiological and clinical data on admission; outcomes; ventilation, respiratory mechanics and oxygenation variables were registered on days 1, 3 and 7 for the entire population and for ARDS categories.Results1525 patients aged 61 ± 13, 69% male, met ARDS criteria; most frequent comorbidities were obesity, hypertension, diabetes and respiratory disease. On admission, 331(21%), 849(56%) and 345(23%) patients had mild, moderate and severe ARDS; all received lung-protective ventilation (mean tidal volumes between 6.3 and 6.7 mL/kg PBW) and intermediate PEEP levels (10–11 cmH2O). PaO2/FiO2, plateau pressure, static compliance, driving pressure, ventilation ratio, pH and D-dimer >2 mg/L remained significantly different among the ARDS categories over time. In-hospital mortality was, respectively, 55%, 58% and 70% (p < 0.000). Independent predictors of changes of PaO2/FiO2 over time were BMI; preexistent respiratory disease; D-dimer >2 mg/L; day 1-PEEP, and day 1-ventilatory ratio.ConclusionHypoxemia in patients with COVID-19-related ARDS is associated with comorbidities, deadspace and activated coagulation markers, and disease severity—reflected by the PEEP level required.

Bedside Selection of Positive End Expiratory Pressure by Electrical Impedance Tomography in Patients Undergoing Veno-Venous Extracorporeal Membrane Oxygenation Support: A Comparison between COVID-19 ARDS and ARDS from Other Etiologies.

Background: The interest in protective ventilation strategies and individualized approaches for patients with severe illness on veno venous extracorporeal support has increased in recent years. Wide heterogeneity exists among patients with COVID-19 related acute respiratory distress syndrome (C-ARDS) and ARDS from other etiologies (NC-ARDS). EIT is a useful tool for the accurate analysis of regional lung volume distribution and allows for a tailored ventilatory setting. The aim of this work is to retrospectively describe the results of EIT assessments performed in patients C-ARDS and NC-ARDS undergoing V-V ECMO support. Methods: A clinical EIT-guided decremental PEEP trail was conducted for all patients included in the study and mechanically ventilated. Results: 12 patients with C-ARDS and 12 patients with NC-ARDS were included in the study for a total of 13 and 18 EIT evaluations, respectively. No significant differences in arterial blood gas, respiratory parameters, and regional ventilation before and after the EIT exam were recorded. The subset of patients with NC-ARDS whose EIT exam led to PEEP modification was characterized by a lower baseline compliance compared with the C-ARDS group: 18 (16–28) vs. 27 (24–30) (p = 0.04). Overdistension significantly increased at higher steps only for the NC-ARDS group. A higher percentage of overdistension was described in patients with NC-ARDS when compared with patients with C-ARDS. Conclusions: EIT is feasible in patients with COVID-19-associated ARDS on veno-venous extracorporeal support and may help in tailoring the PEEP setting. Overall, severe COVID-19-related ARDS presents respiratory characteristics similar to severe “classical” NC-ARDS. However, C-ARDS is associated with a lower risk of overdistension at a higher PEEP level compared with NC-ARDS.

Patient-Ventilator Synchrony in Neurally-Adjusted Ventilatory Assist and Variable Pressure Support Ventilation.

Neurally-adjusted ventilatory assist (NAVA) improves patient-ventilator synchrony and reduces the risk of respiratory over-assistance. Variable pressure support ventilation (PSV) is a recently introduced mode of assisted ventilation that has also shown reduction in patient-ventilator asynchronies. We hypothesized that NAVA would reduce patient-ventilator asynchronies and inspiratory effort compared to variable PSV because breathing variability was intrinsically determined by the patient and not by the ventilator. This study aimed to evaluate patient-ventilator asynchronies and inspiratory effort pressure-time product (PTP) between NAVA and variable PSV in subjects with mild ARDS. After 24 h of controlled mechanical ventilation, subjects (PaO2 /FIO2 200-300 and PEEP level < 10 cm H2O) were randomized in sequence 1:1 by using a web-based encrypted platform and assigned to NAVA or variable PSV groups. Both modes of ventilation were consecutively kept for 24 h unless there were clinical changes. The primary aim of this study was to evaluate differences in asynchrony index (AI) between variable PSV and NAVA. Our secondary aims were to evaluate the coefficient of variation (CV) of breathing patterns and inspiratory effort between the groups. Thirteen subjects were randomized in the NAVA group and 13 subjects in the variable PSV group. AI over time and minute PTP (PTPmin) were not different between NAVA and variable PSV groups (AI t0P = .52, AI t12P = .27, AI t24P = .12; and PTPmin-t0P = .60, PTPmin-t12P = .57, PTPmin-t24P = .85, respectively). CV for tidal volume (VT) and pressure support (PS) was lower in variable PSV group over time compared with NAVA group (P < .05). In this randomized controlled trial including subjects with mild ARDS, NAVA and variable PSV had comparable effects on patient-ventilator synchronies and PTP. However, variable PSV reduced the variability of VT and PS when compared with NAVA.

A retrospective comparison of COVID-19 and seasonal influenza mortality and outcomes in the ICUs of a French university hospital.

SARS-Cov-2 (COVID-19) has become a major worldwide health concern since its appearance in China at the end of 2019. To evaluate the intrinsic mortality and burden of COVID-19 and seasonal influenza pneumonia in ICUs in the city of Lyon, France. A retrospective study. Six ICUs in a single institution in Lyon, France. Consecutive patients admitted to an ICU with SARS-CoV-2 pneumonia from 27 February to 4 April 2020 (COVID-19 group) and seasonal influenza pneumonia from 1 November 2015 to 30 April 2019 (influenza group). A total of 350 patients were included in the COVID-19 group (18 refused to consent) and 325 in the influenza group (one refused to consent). Diagnosis was confirmed by RT-PCR. Follow-up was completed on 1 April 2021. Differences in 90-day adjusted-mortality between the COVID-19 and influenza groups were evaluated using a multivariable Cox proportional hazards model. COVID-19 patients were younger, mostly men and had a higher median BMI, and comorbidities, including immunosuppressive condition or respiratory history were less frequent. In univariate analysis, no significant differences were observed between the two groups regarding in-ICU mortality, 30, 60 and 90-day mortality. After Cox modelling adjusted on age, sex, BMI, cancer, sepsis-related organ failure assessment (SOFA) score, simplified acute physiology score SAPS II score, chronic obstructive pulmonary disease and myocardial infarction, the probability of death associated with COVID-19 was significantly higher in comparison to seasonal influenza [hazard ratio 1.57, 95% CI (1.14 to 2.17); P = 0.006]. The clinical course and morbidity profile of both groups was markedly different; COVID-19 patients had less severe illness at admission (SAPS II score, 37 [28 to 48] vs. 48 [39 to 61], P < 0.001 and SOFA score, 4 [2 to 8] vs. 8 [5 to 11], P < 0.001), but the disease was more severe considering ICU length of stay, duration of mechanical ventilation, PEEP level and prone positioning requirement. After ICU admission, COVID-19 was associated with an increased risk of death compared with seasonal influenza. Patient characteristics, clinical course and morbidity profile of these diseases is markedly different.

Assessment of Regional Ventilation During Recruitment Maneuver by Electrical Impedance Tomography in Dogs.

BackgroundDuring protective mechanical ventilation, electrical impedance tomography (EIT) is used to monitor alveolar recruitment maneuvers as well as the distribution of regional ventilation. This technique can infer atelectasis and lung overdistention during mechanical ventilation in anesthetized patients or in the ICU. Changes in lung tissue stretching are evaluated by monitoring the electrical impedance of lung tissue with each respiratory cycle.ObjectiveThis study aimed to evaluate the distribution of regional ventilation during recruitment maneuvers based on the variables obtained in pulmonary electrical impedance tomography during protective mechanical ventilation, focusing on better lung recruitment associated with less or no overdistention.MethodsProspective clinical study using seven adult client–owned healthy dogs, weighing 25 ± 6 kg, undergoing elective ovariohysterectomy or orchiectomy. The animals were anesthetized and ventilated in volume-controlled mode (7 ml.kg−1) with stepwise PEEP increases from 0 to 20 cmH2O in steps of 5 cmH2O every 5 min and then a stepwise decrease. EIT, respiratory mechanics, oxygenation, and hemodynamic variables were recorded for each PEEP step.ResultsThe results show that the regional compliance of the dependent lung significantly increased in the PEEP 10 cmH2O decrease step when compared with baseline (p < 0.027), and for the nondependent lung, there was a decrease in compliance at PEEP 20 cmH2O (p = 0.039) compared with baseline. A higher level of PEEP was associated with a significant increase in silent space of the nondependent regions from the PEEP 10 cmH2O increase step (p = 0.048) until the PEEP 15 cmH2O (0.019) decrease step with the highest values at PEEP 20 cmH20 (p = 0.016), returning to baseline values thereafter. Silent space of the dependent regions did not show any significant changes. Drive pressure decreased significantly in the PEEP 10 and 5 cmH2O decrease steps (p = 0.032) accompanied by increased respiratory static compliance in the same PEEP step (p = 0.035 and 0.018, respectively).ConclusionsThe regional ventilation distribution assessed by EIT showed that the best PEEP value for recruitment maintenance, capable of decreasing areas of pulmonary atelectasis in dependent regions promoting less overinflation in nondependent areas, was from 10 to 5 cmH2O decreased steps.

Tidal volume significantly affects oxygenation in healthy pigs during high-frequency oscillatory ventilation compared to conventional ventilation

BackgroundThe role of high-frequency oscillatory ventilation (HFOV) has long been debated. Numerous studies documented its benefits, whereas several more recent studies did not prove superiority of HFOV over protective conventional mechanical ventilation (CV). One of the accepted explanations is that CV and HFOV act differently, including gas exchange.MethodsTo investigate a different level of coupling or decoupling between oxygenation and carbon dioxide elimination during CV and HFOV, we conducted a prospective crossover animal study in 11 healthy pigs. In each animal, we found a normocapnic tidal volume (VT) after the lung recruitment maneuver. Then, VT was repeatedly changed over a wide range while keeping constant the levels of PEEP during CV and mean airway pressure during HFOV. Arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were recorded. The same procedure was repeated for CV and HFOV in random order.ResultsChanges in PaCO2 intentionally induced by adjustment of VT affected oxygenation more significantly during HFOV than during CV. Increasing VT above its normocapnic value during HFOV caused a significant improvement in oxygenation, whereas improvement in oxygenation during CV hyperventilation was limited. Any decrease in VT during HFOV caused a rapid worsening of oxygenation compared to CV.ConclusionA change in PaCO2 induced by the manipulation of tidal volume inevitably brings with it a change in oxygenation, while this effect on oxygenation is significantly greater in HFOV compared to CV.

Higher PEEP versus lower PEEP strategies for patients in ICU without acute respiratory distress syndrome: A systematic review and meta-analysis

To evaluate the effects of high and low levels of PEEP on ICU patients without ARDS. We searched public databases (including PubMed, EMBASE, Cochrane Library and Clinicaltrial.gov). The Cochrane Risk of Bias Assessment tool was used to evaluate the quality of the included studies. We included 2307 patients from 24 trials. Although no significant difference was found between high and low PEEP applications in in-hospital mortality (risk ratio[RR] 0.98, 95% confidence interval[CI] [0.81, 1.19], P=0.87), high PEEP indeed decreased the incidence of ARDS, hypoxemia, and increased the level of PaO2/FIO2. In addition, although the overall results did not reveal any advantages of high PEEP in terms of secondary outcomes regarding 28-day mortality, the duration of ventilation, atelectasis, pulmonary barotrauma, hypotension, and so forth, the subgroup analysis concerning the level of low PEEP (ZEEP or not) and patient type (postoperative or medical ones) yielded different results. The TSA results suggested that more RCTs are needed. Although ventilation with high PEEP in ICU patients without ARDS may not reduce in-hospital mortality, the decreased incidences of ARDS and hypoxemia and the improvement in PaO2/FIO2 were found in the high PEEP arm.

Could nebulized heparin be the magic treatment for COVID-19 Pneumonia and ARDS?

Background: The global spread of the novel strain of coronavirus referred to as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the continuous rise in the hospitalization of people suffering from COVID-19 in various parts of the world. The predominant symptoms experienced by patients diagnosed with SARS-CoV-2 infection include pneumonia and acute respiratory distress syndrome (ARDS). These symptoms have contributed to the high mortality rate of COVID-19 patients across the globe. Recent studies have indicated that nebulized unfractionated heparin (UFH) can be employed in the treatment of pneumonia and acute respiratory distress syndrome (ARDS) in hospitalized patients who have been diagnosed with SARS-CoV-2 infection. Case description: The case study for this investigation was a 37-year-old Saudi woman who had muscular dystrophy, bronchial asthma, and diabetes mellitus. This hospitalized patient who was a wheelchair bound was admitted to the intensive care unit (ICU) due to the onset of severe COVID-19 related pneumonia and ARDS. The patient was intubated and placed on high mechanical ventilation support with protective lung strategy (low tidal volume and high PEEP level), prone positioning, administering inhaled nitric oxide therapy, and the intravenous infusion methylprednisolone together with antiviral agents and empiric antibiotics for seven days. Despite the administration of this maximal therapy, she continued to have refractory hypoxemia and severe ARDS. As a result, a high dose of UFH was administered to the patient through nebulization. After administering nine different doses of nebulized UFH, the patient’s oxygenation and inflammatory markers have remarkably improved, then she had a very smooth course and successfully weaned off mechanical ventilation. Conclusion: This treatment strategy resulted in a significant improvement in the P/F ratio, a remarkable reduction in the bilateral lung infiltrates and inflammatory markers and eventually weaning of mechanical ventilation in the COVID-19 patient. This case suggests that nebulized UFH has a strong scientific and biological basis to test its use as a therapy for COVID-19 pneumonia and ARDS as it may offer huge clinical benefit across the time course of the disease as well may prevent progression of infection If administered early at the onset of symptoms, and may finally prevent the needs for mechanical ventilation. Learning points: Randomized controlled trials should be carried out to investigate the clinical impacts of nebulized UFH in both prevention and treatment of COVID-19 pneumonia/AERDS.

Biomarkers of Cholestasis and Liver Injury in the Early Phase of Acute Respiratory Distress Syndrome and Their Pathophysiological Value.

Background: Impaired liver function and cholestasis are frequent findings in critically ill patients and are associated with poor outcomes. We tested the hypothesis that hypoxic liver injury and hypoxic cholangiocyte injury are detectable very early in patients with ARDS, may depend on the severity of hypoxemia, and may be aggravated by the use of rescue therapies (high PEEP level and prone positioning) but could be attenuated by extracorporeal membrane oxygenation (ECMO). Methods: In 70 patients with ARDS, aspartate-aminotransferase (AST), alanin-aminotransferase (ALT) and gamma glutamyltransferase (GGT) were measured on the day of the diagnosis of ARDS and three more consecutive days (day 3, day 5, day 10), total bile acids were measured on day 0, 3, and 5. Results: AST levels increased on day 0 and remained constant until day 5, then dropped to normal on day 10 (day 0: 66.5 U/l; day 3: 60.5 U/l; day 5: 63.5 U/l, day 10: 32.1 U/l), ALT levels showed the exact opposite kinetic. GGT was already elevated on day 0 (91.5 U/l) and increased further throughout (day 3: 163.5 U/l, day 5: 213 U/l, day 10: 307 U/l), total bile acids levels increased significantly from day 0 to day 3 (p = 0.019) and day 0 to day 5 (p < 0.001), but not between day 3 and day 5 (p = 0.217). Total bile acids levels were significantly correlated to GGT on day 0 (p < 0.001), day 3 (p = 0.02), and in a trend on day 5 (p = 0.055). PEEP levels were significantly correlated with plasma levels of AST (day 3), ALT (day 5) and GGT (day 10). Biomarker levels were not associated with the use of ECMO, prone position, the cause of ARDS, and paO2. Conclusions: We found no evidence of hypoxic liver injury or hypoxic damage to cholangiocytes being caused by the severity of hypoxemia in ARDS patients during the very early phase of the disease. Additionally, mean PEEP level, prone positioning, and ECMO treatment did not have an impact in this regard. Nevertheless, GGT levels were elevated from day zero and rising, this increase was not related to paO2, prone position, ECMO treatment, or mean PEEP, but correlated to total bile acid levels.

Positive end-expiratory pressure in COVID-19 acute respiratory distress syndrome: the heterogeneous effects

BackgroundWe hypothesized that as CARDS may present different pathophysiological features than classic ARDS, the application of high levels of end-expiratory pressure is questionable. Our first aim was to investigate the effects of 5–15 cmH2O of PEEP on partitioned respiratory mechanics, gas exchange and dead space; secondly, we investigated whether respiratory system compliance and severity of hypoxemia could affect the response to PEEP on partitioned respiratory mechanics, gas exchange and dead space, dividing the population according to the median value of respiratory system compliance and oxygenation. Thirdly, we explored the effects of an additional PEEP selected according to the Empirical PEEP-FiO2 table of the EPVent-2 study on partitioned respiratory mechanics and gas exchange in a subgroup of patients.MethodsSixty-one paralyzed mechanically ventilated patients with a confirmed diagnosis of SARS-CoV-2 were enrolled (age 60 [54–67] years, PaO2/FiO2 113 [79–158] mmHg and PEEP 10 [10–10] cmH2O). Keeping constant tidal volume, respiratory rate and oxygen fraction, two PEEP levels (5 and 15 cmH2O) were selected. In a subgroup of patients an additional PEEP level was applied according to an Empirical PEEP-FiO2 table (empirical PEEP). At each PEEP level gas exchange, partitioned lung mechanics and hemodynamic were collected.ResultsAt 15 cmH2O of PEEP the lung elastance, lung stress and mechanical power were higher compared to 5 cmH2O. The PaO2/FiO2, arterial carbon dioxide and ventilatory ratio increased at 15 cmH2O of PEEP. The arterial–venous oxygen difference and central venous saturation were higher at 15 cmH2O of PEEP. Both the mechanics and gas exchange variables significantly increased although with high heterogeneity. By increasing the PEEP from 5 to 15 cmH2O, the changes in partitioned respiratory mechanics and mechanical power were not related to hypoxemia or respiratory compliance. The empirical PEEP was 18 ± 1 cmH2O. The empirical PEEP significantly increased the PaO2/FiO2 but also driving pressure, lung elastance, lung stress and mechanical power compared to 15 cmH2O of PEEP.ConclusionsIn COVID-19 ARDS during the early phase the effects of raising PEEP are highly variable and cannot easily be predicted by respiratory system characteristics, because of the heterogeneity of the disease.

Is There an Optimal Positive End-expiratory Pressure to Measure the Internal Jugular Vein Collapsibility Index? A Pilot Study in Mechanically Ventilated Patients

Background: Hemodynamic monitoring its early stabilization is very important in critically ill patients. Evaluating the Internal jugular vein diameter during respiratory cycles by the means of Point-of care ultrasound provides an important, easily available and precise index for monitoring hemodynamic status; a new method which is called Internal Jugular Vein Collapsibility Index (IJV-CI). Any events that alters intrathoracic volumes and pressures may affect this index. In this study we investigate the effects of various levels of positive end-expiratory pressure on this index. Methods: Thirty mechanically ventilated patients were studied. We used three different PEEP levels (0, 5 and 10 cmH2o) and point-of-care ultrasound evaluation of IJV (Internal Jugular Vein) diameter to determine the IJV-CI. The analysis were performed using SPSS V.25.0. Results: Patients were included men (76.6%) and women (33.3%). The mean age of patients was 39.65±3.4 for men and 42.71± 9.34 for women. The IJV-CI were 20.71±11.77 and 24.25±11.46 in PEEP=0 and PEEP=10 cmH20 groups respectively. In 5cmH20-PEEP group median and interquartile range were 16.45(14.8). The IJV-CI in three different PEEP levels were not statistically significantly different. Conclusion: According to the finding of this study, we found no evidence of an optimal PEEP level to measure The IJV-CI.

Evaluation of the influence of individualized protective ventilation on the lung mechanical properties

The work is devoted to the study of the influence of individualized protective ventilation support on pulmonary mecha-nics. The study included 47 patients who underwent open abdominal surgery under general anesthesia. All patients had a moderate to high risk of developing postoperative pulmonary complications by the ARISCAT scale. Intraoperatively, the impact of individualized protective ventilation on respiratory mechanics, namely Ppeak, Pplat, Pdrive, dynamic pulmonary compliance was assessed. Individualized protective respiratory support was ventilation with a tidal volume of 7 ml/kg of ideal body weight, with the selection of the optimal level of positive pressure at the end of exhalation (PEEP), focusing on dynamic pulmonary compliance and performing recruiting maneuver, and then in the case of a decrease in dynamic pulmonary compliance by more than 20 %, followed by re-selection of PEEP. The studied parameters were recorded before and after the recruiting maneuver, as well as on the 30th, 60th, 90th, 120th, 150th, 180th minutes after the recruiting maneuver, depending on the duration of the operation. The use of alveolar straightening techniques led to an improvement in pulmonary mechanics, namely, an increase in dynamic pulmonary compliance by 16 % and a decrease in Pdrive by 17 %. The intraoperative level of PEEP averaged 4 [4; 5] cm of water. No cases of hypoxemia or recurrence of recruiting maneuver were reported. The obtained results indicate that chosen technique of recruiting maneuver is effective and safe, and its use allows reducing the negative impact of mechanical ventilation. The study did not find a statistically significant correlation between the level of PEEP and the value of dynamic pulmonary compliance. Such data prove the need for individual selection of ventilation parameters according to the characteristics of the mechanical properties of each patient.

Особенности применения концепции открытых легких при респираторной терапии тяжелой внебольничной пневмонии

Важным этапом респираторной терапии является оценка рекрутабельности легких пациента и подбор оптимального уровня положительного давления конца выдоха (PEEP). Некорректные настройки параметров искусственной вентиляции легких (ИВЛ) могут существенно ухудшить результаты лечения. Нерекрутабельные легкие пациента требуют попыток привлечения более высокотехнологичных, адаптивно-интеллектуальных режимов ИВЛ. В данной статье нами был описан клинический случай респираторной терапии тяжелой внебольничной пневмонии. Терапия была осложнена нерекрутабельностью легких пациента и клиникой крайне тяжелой гипоксии. Высокие значения PEEP и использование альвеолярных рекрутментов негативно влияли на показатели оксигенации. В качестве альтернативы традиционным режимам нами был применен интеллектуальный режим вентиляции ASV, что улучшило показатели оксигенации. Положительный эффект наблюдался при проведении ИВЛ в prone-положении.

Comparing the Benefits of Titrated PEEP vs Low PEEP in Terms of Mortality in Patients Suffering from Acute Respiratory Distress Syndrome

Objective: To compare the benefits of titrated PEEP vs low PEEP in terms of mortality in patients suffering from acute respiratory distress syndrome&#x0D; Study Design: Randomized clinical trial&#x0D; Place and Duration of Study: Intensive care unit (ICU) of Nishtar Hospital Multan over a period of January 2017 to January 2018.&#x0D; Methodology: Patients were randomly divided into two groups LP group and TP group. TP group received fluids and neuromuscular blockers. Lung recruitment maneuver was done with incremental PEEP level and in the second time by a decremental PEEP maneuver. If levels of PaO2 and FIO2 were same or increasing during one day we stared to decrease the PEEP of 2cm Hg for every 8 hours. .&#x0D; Results: Of the outcome variables, numbers of death within 28 days were significantly higher in the low PEEP group (p-value 0.045 and 0.022, respectively). Development of pneumothorax requiring drainage and incidence of barotrauma within the first 7 days was significantly less in the titrated PEEP group. During the first 28 days, more number of patients in the titrated PEEP group had ventilator free days.&#x0D; Conclusion: In our study we find that the deaths within 28 days, development of pneumothorax requiring drainage and incidence of barotrauma within the first 7 days were significantly higher in the low PEEP group.

Higher CPAP levels improve functional residual capacity at birth in preterm rabbits.

Preterm infants are commonly supported with 4-8 cm H2O continuous positive airway pressures (CPAP), although higher CPAP levels may improve functional residual capacity (FRC). Preterm rabbits delivered at 29/32 days (~26-28 weeks human) gestation received 0, 5, 8, 12, 15 cm H2O of CPAP or variable CPAP of 15 to 5 or 15 to 8 cm H2O (decreasing ~2 cm H2O/min) for up to 10 min after birth. FRC was lower in the 0 (6.8 (1.0-11.2) mL/kg) and 5 (10.1 (1.1-16.8) mL/kg) compared to the 15 (18.8 (10.9-22.4) mL/kg) cm H2O groups (p = 0.003). Fewer kittens achieved FRC > 15 mL/kg in the 0 (20%), compared to 8 (36%), 12 (60%) and 15 (73%) cm H2O groups (p = 0.008). While breathing rates were not different (p = 0.096), apnoea tended to occur more often with CPAP < 8 cm H2O (p = 0.185). CPAP belly and lung bulging rates were similar whereas pneumothoraces were rare. Lowering CPAP from 15 to 5, but not 15 to 8 cm H2O, decreased FRC and breathing rates. In all, 15 cm H2O of CPAP improved lung aeration and reduced apnoea, but did not increase the risk of lung over-expansion, pneumothorax or CPAP belly immediately after birth. FRC and breathing rates were maintained when CPAP was decreased to 8 cm H2O. Although preterm infants are commonly supported with 4-8 cm H2O CPAP at birth, preclinical studies have shown that higher PEEP levels improve lung aeration. In this study, CPAP levels of 15 cm H2O improved lung aeration and reduced apnoea in preterm rabbit kittens immediately after birth. In all, 15 cm H2O CPAP did not increase the risk of lung over-expansion (indicated by bulging between the ribs), pneumothorax, or CPAP belly. These results can be used when designing future studies on CPAP strategies for preterm infants in the delivery room.

Comparing the Intellivent-ASV® Mode with Conventional Ventilation Modes during Weaning after Uncomplicated Cardiac Surgery

The objective: to compare efficacy and safety of Intellivent-ASV® with conventional ventilation modes during weaning in the patients after cardiac surgery.Subjects and methods. In this randomized controlled trial, 40 adult patients were ventilated with conventional ventilation modes and 40 with Intellivent-ASV after uncomplicated cardiac surgery. Eight physicians were involved in the study.Care of both groups was standardized, except for the modes of postoperative ventilation.We compared:- The physician’s workload, through accounting number of manual ventilator settings and time they spent near the ventilator in every group,- Duration of tracheal intubation in ICU,- Evaluation of ventilation safety by considering driving pressure, mechanical power, positive end expiratory pressure, and tidal volume level,- The frequency of adverse events, postoperative complications, and lethality.Results. There were significant differences in the duration of respiratory support in ICU: 226 ± 31 min (Intellivent Group) vs 271 ± 78 min (Control Group) (p = 0.0013).In Intellivent Group, the number of manual ventilator settings and time spent by physicians near the ventilator before tracheal extubation were significantly lower: 0 vs 4 (2–6), and 35 (25–53) sec vs 164 ± 69 sec respectively (p &lt; 0.001 in both cases).Intellivent-ASV provided significantly more protective ventilation through reduction in the driving pressure, tidal volume, FiO2 and PEEP levels but no difference was noted between paO2/FiO2 ratio. ∆P and Vt were significantly lower in Intellivent Group – ∆P on mechanical ventilation was 6 (5–7) cm H2O vs 7.25 (6.5–9.5) cm H2O (p &lt; 0.001); Vt on mechanical ventilation was 6 (5.2–7) vs 7 (6–9.5) ml/kg/PBW (p = 0.000003). PEEP and FiO2 levels were also significantly lower in Intellivent Group, PEEP on mechanical ventilation was 5 (5–7.5) cm H2O vs 7 (5–11.5) cm H2O and FiO2 level was 26 (22–30) % vs 34 (30–40) %.There were no significant differences between the groups in frequency of adverse events and duration of ICU and hospital stay.Conclusion. Application of Intellivent-ASV mode after uncomplicated cardiac surgery provides more protective mechanical ventilation and reduces the physician’s workload without compromising the quality of respiratory support and safety of patients.