Mode Of Ventilatory Support Research Articles

Impact of Pressure Targeted Modes of Ventilation on Diaphragmatic Function as Assessed Using Ultrasonography in Critically Ill Patients with Cerebral Insult

Abstract Background Mechanical ventilation (MV) causes diaphragmatic atrophy and reduces diaphragmatic efficiency. Patients with diaphragmatic dysfunction (DD) have longer MV durations and intensive care unit (ICU) stay. There is currently a scarcity of data on the effect of different modes of MV on diaphragmatic function and ultrasound-guided assessment of diaphragmatic efficiency. Methodology Sixty mechanically ventilated patients were randomly divided into four equal groups (15 each), patients were ventilated using either Assist Control Pressure Controlled mode (ACPC group)(Group A), Synchronized Intermittent Mandatory Ventilation Pressure Controlled mode (SIMV)(Group S), Bi-level Positive Airway Pressure mode (BiPAP)(Group B), or Pressure Support Ventilation mode (PSV)(Group P). The primary outcomes were diaphragmatic motion & structure in terms of Diaphragmatic Excursion (DE) & Diaphragmatic Thickness Fraction (DTF) respectively. The duration of the ICU stay was the secondary outcome. Results The PSV group had the highest DE indicating better diaphragmatic function. In addition, MV for longer durations led to diaphragmatic thinning and decreased DTF resulting in DD. Conclusion Among the various modes of ventilation employed in the study, PSV was found to be the mode with the lowest risk of DD. Trial Registry PACTR202112653971335.

Neurally Adjusted Ventilatory Assist Versus Pressure Support Ventilation: A Comprehensive Review.

Mechanical ventilation serves as crucial life support for critically ill patients. Although it is life-saving prolonged ventilation carries risks and complications like barotrauma, Ventilator-associated pneumonia, sepsis, and many others. Optimizing patient-ventilator interactions and facilitating early weaning is necessary for improved intensive care unit (ICU) outcomes. Traditionally Pressure support ventilation (PSV) mode is widely used for weaning patients who are intubated and mechanically ventilated. Neurally adjusted ventilatory assist (NAVA) mode of the ventilator is an emerging ventilator mode that delivers pressure depending on the patient's respiratory drive, which in turn prevents over-inflation and improves the patient's ventilator interactions. Our article revises and compares the effectiveness of NAVA compared to PSV ventilation under different contexts. Overall we conclude that NAVA level of ventilation can be safely administered in a patient with acute respiratory failure, provided diaphragmatic paralysis is not considered. NAVA improves asynchrony index, wean-off time, and sleep quality and is associated with increased ventilator-free days. These results are based on small-scale studies with low power, and further studies are warranted in large-scale cohorts with more diverse populations to confirm these results.

Effect of reverse Trendelenburg position and positive pressure ventilation on safe non-hypoxic apnea period in obese, a randomized-control trial

PurposeThere is an elevated incidence of hypoxemia during the airway management of the morbidly obese. We aimed to assess whether optimizing body position and ventilation during pre-oxygenation allow a longer safe non-hypoxic apnea period (SNHAP).MethodsFifty morbidly obese patients were recruited and randomized for this study. Patients were positioned and preoxygenated for three minutes in the ramp position associated with spontaneous breathing without additional CPAP or PEEP (RP/ZEEP group) or in the reverse Trendelenburg position associated with pressure support ventilation mode with pressure support of 8 cmH2O and an additional 10 cmH2O of PEEP while breathing spontaneously (RT/PPV group) according to randomization.ResultsThe SNHAP was significantly longer in the RT/PPV group (258.2 (55.1) vs. 216.7 (42.3) seconds, p = 0.005). The RT/PPV group was also associated to a shorter time to obtain a fractional end-tidal oxygen concentration (FEtO2) of 0.90 (85.1(47.8) vs 145.3(40.8) seconds, p < 0.0001), a higher proportion of patients that reached the satisfactory FEtO2 of 0.90 (21/24, 88% vs. 13/24, 54%, p = 0.024), a higher FEtO2 during preoxygenation (0.91(0.05) vs. 0.89(0.01), p = 0.003) and a faster return to 97% oxygen saturation after ventilation resumption (69.8 (24.2) vs. 91.4 (39.2) seconds, p = 0.038).ConclusionIn the morbidly obese population, RT/PPV, compared to RP/ZEEP, lengthens the SNHAP, decreases the time to obtain optimal preoxygenation conditions, and allows a faster resuming of secure oxygen saturation. The former combination allows a more significant margin of time for endotracheal intubation and minimizes the risk of hypoxemia in this highly vulnerable population.Trial registrationNCT02590406, 29/10/2015.

Impact of pressure-targeted modes of ventilation on diaphragmatic function as assessed using ultrasonography in critically ill patients with cerebral insult: a randomized clinical trial

BackgroundMechanical ventilation causes diaphragmatic atrophy and reduces diaphragmatic efficiency. Patients with diaphragmatic dysfunction have longer mechanical ventilation durations and intensive care unit stay. There is currently a scarcity of data on the effect of different modes of mechanical ventilation on diaphragmatic function and ultrasound-guided assessment of diaphragmatic efficiency.ResultsSixty mechanically ventilated patients were randomly divided into four equal groups (15 each): patients were ventilated using either assist control pressure-controlled mode (group A), synchronized intermittent mandatory ventilation pressure-controlled mode (group S), bi-level-positive airway pressure mode (group B) or pressure support ventilation mode (group P). The primary outcome was to assess the diaphragmatic excursion, while the secondary outcomes were to assess the diaphragmatic thickness fraction and the duration of the ICU stay. Patients in the P group had the highest diaphragmatic excursion indicating better diaphragmatic function.ConclusionsWhen compared to other pressure-targeted ventilation modes, the pressure support ventilation mode may have the least risk of diaphragmatic dysfunction as preserves diaphragmatic structure and strength.Trial registrationThe clinical trial was retrospectively registered at http://www.pactr.org PACTR202112653971335.

Utilizing Spontaneous Ventilation Modes in Patients Underwent Corrective Surgery for Right Ventricular Outflow Tract Obstructive Congenital Heart Disease: A Crossover Study.

This study aimed to determine whether the hemodynamics of patients with right ventricle outflow tract obstructive congenital heart disease (RVOTO-CHD) improve after corrective surgery by changing the ventilation mode. Patients with RVOTO-CHD who underwent corrective surgery were enrolled in this study. Echocardiography and advanced hemodynamic monitoring were performed using the pulse indicator continuous cardiac output (PiCCO) technology in the pressure-regulated volume control (PRVC) mode, followed with switching to the pressure support ventilation (PSV) mode and neurally adjusted ventilatory assist (NAVA) mode in random order. Overall, 31 patients were enrolled in this study from April 2021 to October 2021. Notably, changing the ventilation mode from PRVC to a spontaneous mode (PSV or NAVA) led to better cardiac function outcomes, including right ventricular cardiac index (PRVC: 3.19 1.07 L/min/ vs. PSV: 3.45 1.32 L/min/ vs. NAVA: 3.82 1.03 L/min/ , p 0.05) and right ventricle contractility (tricuspid annular peak systolic velocity) (PRVC: 6.58 1.40 cm/s vs. PSV: 7.03 1.33 cm/s vs. NAVA: 7.94 1.50 cm/s, p 0.05), as detected via echocardiography. Moreover, in the NAVA mode, PiCCO-derived cardiac index (PRVC: 2.92 0.54 L/min/ vs. PSV: 3.04 0.56 L/min/ vs. NAVA: 3.20 0.62 L/min/ , p 0.05), stroke volume index (PRVC: 20.38 3.97 mL/ vs. PSV: 21.23 4.33 mL/ vs. NAVA: 22.00 4.33 mL/ , p 0.05), and global end diastolic index (PRVC: 295.74 78.39 mL/ vs. PSV: 307.26 91.18 mL/ vs. NAVA: 323.74 102.87 mL/ , p 0.05) improved, whereas extravascular lung water index significantly reduced (PRVC: 16.42 7.90 mL/kg vs. PSV: 15.42 5.50 mL/kg vs. NAVA: 14.4 4.19 mL/kg, p 0.05). Furthermore, peak inspiratory pressure, mean airway pressure, driving pressure, and compliance of the respiratory system improved in the NAVA mode. No deaths were reported in this study. We found that utilizing spontaneous ventilator modes, especially the NAVA mode, after corrective surgery in patients with RVOTO-CHD may improve their right heart hemodynamics and respiratory mechanics. However, further randomized controlled trials are required to verify the advantages of spontaneous ventilation modes in such patients. NCT04825054.

Fluid overload: clinical outcomes in pediatric intensive care unit

ObjectiveThe aim of this study was to analyze the effects of fluid overload related to mechanical ventilation, renal replacement therapy, and evolution to discharge or death in critically ill children. MethodsA retrospective study in a Pediatric Intensive Care Unit for two years. Patients who required invasive ventilatory support and vasopressor and/or inotropic medications were considered critically ill. Results70 patients were included. The mean age was 6.8 ± 6 years. There was a tolerable increase in fluid overload during hospitalization, with a median of 2.45% on the first day, 5.10% on the third day, and 8.39% on the tenth day. The median fluid overload on the third day among those patients in pressure support ventilation mode was 4.80% while the median of those who remained on controlled ventilation was 8.45% (p = 0.039). Statistical significance was observed in the correlations between fluid overload measurements on the first, third, and tenth days of hospitalization and the beginning of renal replacement therapy (p = 0.049) and between renal replacement therapy and death (p = 0.01). The median fluid overload was 7.50% in patients who died versus 4.90% in those who did not die on the third day of hospitalization (p = 0.064). There was no statistically significant association between death and the variables sex or age. ConclusionsThe fluid overload on the third day of hospitalization proved to be a determinant for the clinical outcomes of weaning from mechanical ventilation, initiation of renal replacement therapy, discharge from the intensive care unit, or death among these children.

Perioperative hemodynamic protective assessment of adaptive support ventilation usage in pediatric surgical patients.

The aim of this study was to evaluate the hemodynamic protective effects of perioperative ventilation in pressure-controlled ventilation (PCV) and adaptive support ventilation (ASV) modes based on non-invasive hemodynamic monitoring indicators. The study included 32 patients who were scheduled for planned open abdominal surgery. Depending on the chosen ventilation strategy, patients were included in two groups of PCV mode ventilation (n=14) and ASV mode ventilation (n=18). The hemodynamic effects of the ventilation strategies were assessed by estimated continuous cardiac output (esCCO) and cardiac index (esCCI). Preoperative cardiac output (CO) was 6.1±1.3 L/min in group 1 patients and 6.3±0.8 L/min in group 2 patients, and preoperative cardiac index (CI) was 3.9±0.4 L/min/m2 in group 1 patients and 3.8±0.8 L/min/m2 in group 2 patients. The ejection fraction (EF) in group 1 subjects was 55.4%±0.3%; this rate was 56.5%±0.5% in group 2 subjects. Group 1 patients experienced a 14.7% CO decrease to 5.2±0.7 L/min, a 17.9% CI decrease to 3.2±0.6 L/min/m2 , and a 12.8% mean arterial pressure decrease to 82.3±9.4 mm Hg 30 minutes after the start of surgery. One hour after the start of surgery, the CO mean values of group 2 patients were lower than baseline by 7.9% and differed from the dynamics of patients in group 1, in whom CO was lower than baseline by 13.1%. At the end of the operation, the CO values were lower than baseline by 11.5% and 6.3% in patients of groups 1 and 2, respectively. Our data showed that the changes in EF during and after surgery correlated with CO indicators determined by the esCCO. In our study, perioperative ventilation in ASV mode was more protective than PCV mode and was characterized by lower tidal volume (16.2%) and driving pressure (12.1%). Hemodynamically-controlled mechanical ventilation reduces the negative impact of cardiopulmonary interactions.

Comparison of Effectiveness of Pressure Support and Mandatory Ventilation Modes at the End of General Combined Anesthesia

The objective: to compare effectiveness of pressure support and mandatory ventilation modes at the final stage of general anesthesia.Subjects and Methods. 58 patients were included in the study. All patients underwent laparoscopic or open surgery under combined general anesthesia with muscle relaxants and tracheal intubation. At the end of the operation, after suturing the muscle layer, patients were randomly divided into two groups, depending on the further mode of ventilation: the mandatory mode group with dual control until extubation (n = 29) and the spontaneous breathing mode group with pressure support (n = 29). The time of awakening, the severity of post-extubation cough, hemodynamic parameters and oxygenation immediately before and 5 minutes after extubation were assessed.Results. In the groups of patients, statistically significant differences were observed in the time of awakening (252 ± 67 sec and 426 ± 71 sec in PSV and PCV-VG Groups, respectively), extubation (287 ± 55 sec and 464 ± 67 sec in the PSV and PCV-VG groups, respectively), and transfer from the operating room (473 ± 60 sec and 687 ± 77 sec in the PSV and PCV-VG groups, respectively) (p &lt; 0.0001). Also, patients receiving PSV respiratory support had higher saturation levels 5 minutes after extubation (p &lt; 0.0001), and heart rate and mean arterial pressure immediately before extubation were lower than in the mandatory ventilation group (p = 0.013 and p &lt; 0.0001, respectively). In addition, in the mode of spontaneous breathing with pressure support, a lower severity of post-extubation cough was observed (p = 0.003).Conclusion. The use of a spontaneous breathing mode with pressure support at the end of general combined anesthesia has several advantages versus mandatory ventilation mode. These advantages include faster awakening, extubation and transfer of the patient to the ward, lower severity of post-extubation cough, as well as better gas exchange after extubation, lower intensity of hypertension and tachycardia before it.

Pathophysiologically Based Ventilatory Management of Severe Bronchopulmonary Dysplasia.

Both “new” and “old” bronchopulmonary dysplasia features overlap in preterm infants with severe bronchopulmonary dysplasia. The optimal ventilation strategy for infants with severe bronchopulmonary dysplasia has not been clarified yet. Principally, the lung is a multi-compartmental heterogeneous tissue with regionally varying compliance and resistance.Generally, 2 critical strategical errors are common while ventilating infants with established bronchopulmonary dysplasia: (i) ventilatory management as if they are still in the acute phase of respiratory distress syndrome and (ii) early extubation attempts with the aim of reducing ventilator-induced lung injury. Considering the heterogeneous character of bronchopulmonary dysplasia, although there is no unique formulation for optimal ventilation, the most physiologically appropriate ventilation mode may be the combined mode of volume-guaranteed synchronized intermittent mechanical ventilation and pressure support ventilation. With the volume-guaranteed synchronized intermittent mechanical ventilation mode, slow compartments of the lung with high resistance and low compliance can be adequately ventilated, while fast compartments having relatively normal resistance and compliance can be ventilated well with the pressure support ventilation mode. The following settings are advisable: frequency = 12-20 breaths per minute, tidal volume = 10-15 mL/min, positive end expiratory pressure = 7-12 cmH2O, and inspiratory to expiratory time ratio = 1 : 5. Higher oxygen saturations such as 92%-95% should be targeted to avoid subsequent pulmonary hypertension.In conclusion, there is no evidence-based ventilation recommendation for infants with severe bronchopulmonary dysplasia. However, given the changing pattern of the disease and the underlying pathophysiology, these infants should not be ventilated as if they were in the acute phase of respiratory distress syndrome.

Respiratory support in severe traumatic brain injury (literature review)

Patients with traumatic brain injury (TBI) are the largest group of victims at the emergency departments. Up to 20% of patients with severe TBI require endotracheal intubation and prolonged mechanical ventilation. The ventilation parameters choice should be focused on the normal arterial blood gas composition. Hypoxia causes secondary damage to the brain tissue, and hyperoxia carries risks of oxygen toxicity. Hypercapnia leads to cerebral vasodilatation, increased intracranial pressure (ICP) and the risk of cerebral edema. Hypocapnia promotes cerebral vasoconstriction, which reduces cerebral blood flow and ICP, but also leads to cerebral tissue ischemia, so prolonged hyperventilation in TBI is not currently recommended. Patients with TBI often require sedation to synchronize with the respirator. The drugs of choice are propofol and midazolam. Routine use of muscle relaxants is not recommended. The initial ventilation mode should provide a certain respiration rate to achieve normocapnia, while allowing the patient to make breathing attempts. Support ventilation modes are used while weaning from mechanical ventilation. Promising in predicting extubation success is the assessment of the VISAGE score, which includes visual pursuit, swallowing, age, and the Glasgow coma score. Modern principles of respiratory support in severe TBI include: tracheal intubation by Glasgow coma score ≤8 ; early mechanical ventilation; PaO2 80-120 mm Hg (SaO2 ≥95%); PaCO2 35-45 mm Hg; tidal volume ≤8 ml/kg; respiratory rate ≈20/min; PEEP ≥5 cm H2O; head elevation by 30°; sedation in poor synchronization with the respirator; weaning through support ventilation modes; extubation when reaching 3 points on the VISAGE scale; early (up to 4 days) tracheotomy in predicted extubation failure.

Mechanical ventilation in patients with severe traumatic brain injury: modern guidelines review

Traumatic brain injury is the most common group of injuries among victims admitted to the emergency departments. Up to 20 % of individuals with brain damage require endotracheal intubation and mechanical ventilation, the duration of which is significantly longer than in non-neurological patients. Such patients have a higher incidence of acute respiratory distress syndrome and ventilator-associated pneumonia, and weaning and extubation are associated with significant difficulties. However, patients with traumatic brain injury are often excluded from randomized trials, and international guidelines for the treatment of severe traumatic brain injury do not provide clear ventilation strategies. Analysis of the literature allowed us to identify modern principles of respiratory support in severe traumatic brain injury, which include: tracheal intubation in Glasgow coma scale score of ≤ 8 points; early mechanical ventilation; PaO2 in the range of 80–120 mm Hg (SaO2 ≥ 95 %), PaCO2 — 35–45 mm Hg; tidal volume ≤ 8 ml/kg; respiratory rate ≈ 20/min; PEEP ≥ 5 cm H2O; head elevation by 30°; sedation in poor synchronization with the respirator; weaning from the respirator through the use of support ventilation modes; extubation when reaching 3 points on the VISAGE scale; early (up to 4 days) tracheostomy in predicted extubation failure.

Паліативна та хоспісна допомога дітям

Актуальність. Паліативна та хоспісна допомога дітям є як філософією, так і методом організації надання індивідуалізованої допомоги дітям із життєво-загрозливими порушеннями. Її метою є підвищення якості життя для невиліковно хворих дітей та їх сімей, попередження та/або мінімізація страждань, оптимізація функціонування організму хворої дитини, надання можливостей для персонального й духовного зростання. Наприклад, у США приблизно 44 тисячі дітей помирають за рік, більшості з них ніколи б не була надана хоспісна допомога. Водночас серед дітей, які потребують такої допомоги, менше 10 % користуються нею наприкінці життя. Мета. Привернення уваги суспільства (та медичної спільноти, зокрема) до необхідності створення достатньої кількості сервісів (центрів) паліативної та хоспісної допомоги дітям, а також наведення прикладу роботи мобільного хоспісу для дітей у Західноукраїнському дитячому спеціалізованому медичному центрі. Результати. Вже шість років працівники Західноукраїнського спеціалізованого дитячого медичного центру на волонтерських засадах опікуються невиліковно хворими дітьми вдома, які були госпіталізовані у відділення анестезіології та інтенсивної терапії у критичному стані і за умови стабілізації стану виписані, а батьків навчають догляду за тяжкохворими дітьми в домашніх умовах. Це насамперед діти з тяжкими вродженими вадами, що не підлягають корекції, з тяжкими органічними ураженнями центральної нервової системи, прогресуючими неврологічними захворюваннями (міастеніями), онкологічними захворюваннями, що не піддаються специфічному лікуванню, генетичними захворюваннями (синдромом Вердніга — Гоффмана, синдромом Едвардса тощо). Основними критеріями нашої співпраці з родинами невиліковно хворих дітей є життя без болю та інших тяжких симптомів, допомога сім’ї, увага та повага, індивідуальний підхід. У січні 2017 року завдяки активності суспільства, партнерській співпраці нам в умовах обмежених ресурсів вдалося створити у Західноукраїнському дитячому спеціалізованому медичному центрі відділення «Мобільний хоспіс для дітей». Сьогодні пацієнтами хоспісу є 26 дітей, які мешкають у різних населених пунктах Львівщини. Чотирнадцять дітей дихають через трахеостому, семеро з них — завдяки портативним апаратам штучної вентиляції легень у режимі допоміжної вентиляції (SIMV + PSV). Вісім наших пацієнтів харчуються спеціальними сумішами через гастростому. Першими в Україні ми почали використовувати такий метод харчування дітей у паліативній терапії. Проте у Львівській області щорічно потребують паліативної допомоги 40–50 дітей. Створення відділення «Мобільний хоспіс для дітей» буде забезпечувати реалізацію мультидисциплінарного підходу до надання паліативної допомоги дітям у всіх його аспектах. Висновки. Паліативна та хоспісна допомога передбачає мультидисциплінарний підхід у лікуванні дитини з обмеженою тривалістю життя внаслідок невиліковного захворювання та спрямована на поліпшення якості життя дитини з тяжкими хронічними захворюваннями, а також на підтримку сім’ї.

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.

Expiratory Pause Maneuver to Assess Inspiratory Muscle Pressure During Assisted Mechanical Ventilation: A Bench Study.

The generation of excessive inspiratory muscle pressure (Pmus) during assisted mechanical ventilation in patients with respiratory failure may result in acute respiratory muscle injury and/or fatigue, and exacerbate ventilator-induced lung injury. A readily available noninvasive surrogate measure of Pmus may help in titrating both mechanical ventilation and sedation to minimize these risks. This bench study explored the feasibility and accuracy of using a ventilator's expiratory pause hold function to measure Pmus across multiple operators. A standardized technique for executing a brief (<1 s) expiratory pause maneuver was used to measure the airway occlusion pressure change (Δ Paw) by using 3 simulated Pmus (Δ Pmus: 5, 10, 15 cm H2O) under (1) pressure support ventilation (0, 10, 15 cm H2O), (2) volume and pressure-regulated volume ventilation, (3) flow and pressure-triggering, and (4) varying levels of PEEP and pressure-rise time. Individual and grouped measurements were made by 4-7 clinicians on 3 different ventilators. The concordance between occlusion Δ Paw and Δ Pmus was arbitrarily set at ≤ 2 cm H2O. Data were evaluated by using analysis of variance and the Tukey-Kramer posttest. Correlation was assessed by using the Pearson R test; bias and precision were assessed by using the Bland-Altman method. Alpha was set at 0.05. Grouped expiratory pause maneuver measurements of occlusion Δ Paw across simulated Δ Pmus, mode and level of ventilatory support showed reasonable concordance, regardless of the ventilator used. Occlusion Δ Paw accuracy frequently decreased by ∼3 cm H2O when both pressure support ventilation and Δ Pmus reached 15 cm H2O. Expiratory pause maneuver accuracy was not affected by trigger mechanism and/or sensitivity, PEEP, or the post-trigger pressurization rate. In general, only small differences in Δ Paw occurred among the individual operators. The expiratory pause maneuver generally provided reproducible, stable approximations of Δ Pmus across ventilators and ventilator settings, and a range of simulated effort. Technique standardization produced relatively consistent results across multiple operators. The expiratory pause maneuver seemed feasible for general use in monitoring inspiratory effort during assisted mechanical ventilation.

Second wave of COVID-19 pandemic and the surge of mucormycosis: Lessons learnt and future preparedness: Indian Society of Anaesthesiologists (ISA National) Advisory and Position Statement.

Second wave of COVID-19 pandemic and the surge of mucormycosis: Lessons learnt and future preparedness: Indian Society of Anaesthesiologists (ISA National) Advisory and Position Statement.

Comparison of different methods of obtaining the rapid shallow breathing index

ObjectiveTo compare the Rapid Shallow Breathing Index (RSBI) obtained by the ventilometer and from mechanical ventilation parameters. MethodsRandomized crossover trial, including 33 intubated patients, on mechanical ventilation for at least 24 hours, undergoing spontaneous breathing test. Patients were submitted to the measurement of RSBI by four methods: disconnected from the ventilator through the ventilometer; in Pressure Support Ventilation (PSV) mode at a pressure of 7.ßcm H2O; in Continuous Positive Airway Pressure (CPAP) mode at a pressure of 5.ßcmH2O with flow trigger; in CPAP mode at a pressure of 5.ßcmH2O with pressure trigger. ResultsNo significant difference was detected between the RSBI obtained by the ventilometer and in the CPAP mode with flow and pressure triggers, however, in the PSV mode, the values were lower than in the other measurements (p.ß<.ß0.001). By selecting patients from the sample with higher RSBI (... 80 cycles.min-1.L-1), the value of the index obtained by the ventilometer was higher than that obtained in the three options of ventilation methods. ConclusionThe RSBI obtained in the CPAP mode at a pressure of 5.ßcmH2O, in both triggers types, did not differ from that measured by the ventilometer; it is, therefore, an alternative when obtaining it from mechanical ventilation parameters is necessary. However, in the presence of borderline values, the RSBI measured by ventilometer is recommended, as in this method the values are significantly higher than in the three ventilation modalities investigated.

An interpretable 1D convolutional neural network for detecting patient-ventilator asynchrony in mechanical ventilation

Background and ObjectivePatient-ventilator asynchrony (PVA) is the result of a mismatch between the need of patients and the assistance provided by the ventilator during mechanical ventilation. Because the poor interaction between the patient and the ventilator is associated with inferior clinical outcomes, effort should be made to identify and correct their occurrence. Deep learning has shown promising ability in PVA detection; however, lack of network interpretability hampers its application in clinic. MethodsWe proposed an interpretable one-dimensional convolutional neural network (1DCNN) to detect four most manifestation types of PVA (double triggering, ineffective efforts during expiration, premature cycling and delayed cycling) under pressure control ventilation mode and pressure support ventilation mode. A global average pooling (GAP) layer was incorporated with the 1DCNN model to highlight the sections of the respiratory waveform the model focused on when making a classification. Dilation convolution and batch normalization were introduced to the 1DCNN model for compensating the reduction of performance caused by the GAP layer. ResultsThe proposed interpretable 1DCNN exhibited comparable performance with the state-of-the-art deep learning model in PVA detection. The F1 scores for the detection of four types of PVA under pressure control ventilation and pressure support ventilation modes were greater than 0.96. The critical sections of the waveform used to detect PVA were highlighted, and found to be well consistent with the understanding of the respective type of PVA by experts. ConclusionsThe findings suggest that the proposed 1DCNN can help detect PVA, and enhance the interpretability of the classification process to help clinicians better understand the results obtained from deep learning technology.

Prediction of extubation outcome in mechanically ventilated patients: Development and validation of the Extubation Predictive Score (ExPreS).

Despite the best efforts of intensive care units (ICUs) professionals, the extubation failure rates in mechanically ventilated patients remain in the range of 5%–30%. Extubation failure is associated with increased risk of death and longer ICU stay. This study aimed to identify respiratory and non-respiratory parameters predictive of extubation outcome, and to use these predictors to develop and validate an “Extubation Predictive Score (ExPreS)” that could be used to predict likelihood of extubation success in patients receiving invasive mechanical ventilation (IMV). Derivation cohort was composed by patients aged ≥18 years admitted to the ICU and receiving IMV through an endotracheal tube for >24 hours. The weaning process followed the established ICU protocol. Clinical signs and ventilator parameters of patients were recorded during IMV, in the end phase of weaning in pressure support ventilation (PSV) mode, with inspiratory pressure of 7 cm H2O over the PEEP (positive end expiratory pressure). Patients who tolerated this ventilation were submitted to spontaneous breathing trial (SBT) with T-tube for 30 minutes. Those who passed the SBT and a subsequent cuff-leak test were extubated. The primary outcome of this study was extubation success at 48 hours. Parameters that showed statistically significant association with extubation outcome were further investigated using the receiver operating characteristics (ROC) analysis to assess their predictive value. The area under the curve (AUC) values were used to select parameters for inclusion in the ExPreS. Univariable logistic regression analysis and ROC analysis were performed to evaluate the performance of ExPreS. Patients’ inclusion and statistical analyses for the prospective validation cohort followed the same criteria used for the derivation cohort and the decision to extubate was based on the ExPreS result. In the derivation cohort, a total of 110 patients were extubated: extubation succeeded in 101 (91.8%) patients and failed in 9 (8.2%) patients. Rapid shallow-breathing index (RSBI) in SBT, dynamic lung compliance, duration of IMV, muscle strength, estimated GCS, hematocrit, and serum creatinine were significantly associated with extubation outcome. These parameters, along with another parameter—presence of neurologic comorbidity—were used to create the ExPreS. The AUC value for the ExPreS was 0.875, which was higher than the AUCs of the individual parameters. The total ExPreS can range from 0 to 100. ExPreS ≥59 points indicated high probability of success (OR = 23.07), while ExPreS ≤44 points indicated low probability of success (OR = 0.82). In the prospective validation cohort, 83 patients were extubated: extubation succeeded in 81 (97.6%) patients and failed in 2 (2.4%) patients. The AUC value for the ExPreS in this cohort was 0.971. The multiparameter score that we propose, ExPreS, shows good accuracy to predict extubation outcome in patients receiving IMV in the ICU. In the prospective validation, the use of ExPreS decreased the extubation failure rate from 8.2% to 2.4%, even in a cohort of more severe patients.

Does Neurally Adjusted Ventilatory Assist Compared to Pressure Support Ventilation Decrease Patient Ventilator Asynchrony?

BACKGROUND: Patient-mechanical ventilator (MV) asynchrony despite optimal adjustment of MV parameters is a common problem that is partly associated with difficult weaning of MV. Neurally adjusted ventilatory assist (NAVA) is a mode of proportional ventilation that count on diaphragmatic activity (measured by special esophageal probe and expressed as diaphragm electrical [Edi]) to provide proportional support to patient effort which differs from one breath to another according to Edi signal. AIM: The purpose of this trial is to determine the impact of NAVA compared to pressure support ventilation (PSV) mode in decreasing patient-MV asynchrony and hemodynamic effect in patients on MV with expected difficult weaning. MATERIALS AND METHODS: This prospective interventional trial was conducted on 30 critically ill on MV with expected difficult weaning. First, patients were put on PSV mode for 24 h. Then, patients were put on NAVA mode (for weaning) for the next 24 h. The incidence of different types of asynchrony in both modes was investigated. RESULTS: NAVA mode significantly reduced the asynchrony index when compared to PSV (1.1 ± 0.39% vs. 2.8 ± 1.1, respectively, p &lt; 0.001), P/F ratio was significantly higher during NAVA (250 in NAVA vs. 210 in PSV, p &lt; 0.001), heart rate, and mean arterial blood pressure were significantly reduced during NAVA (p &lt; 0.001 and 0.015, respectively). CONCLUSIONS: Compared to PSV, NAVA-reduced patient-MV asynchrony significantly and increased the P/F ratio significantly with better hemodynamics.

Mechanical ventilation strategy for pulmonary rehabilitation based on patient-ventilator interaction

Mechanical ventilation is an effective medical means in the treatment of patients with critically ill, COVID-19 and other pulmonary diseases. During the mechanical ventilation and the weaning process, the conduct of pulmonary rehabilitation is essential for the patients to improve the spontaneous breathing ability and to avoid the weakness of respiratory muscles and other pulmonary functional trauma. However, inappropriate mechanical ventilation strategies for pulmonary rehabilitation often result in weaning difficulties and other ventilator complications. In this article, the mechanical ventilation strategies for pulmonary rehabilitation are studied based on the analysis of patient-ventilator interaction. A pneumatic model of the mechanical ventilation system is established to determine the mathematical relationship among the pressure, the volumetric flow, and the tidal volume. Each ventilation cycle is divided into four phases according to the different respiratory characteristics of patients, namely, the triggering phase, the inhalation phase, the switching phase, and the exhalation phase. The control parameters of the ventilator are adjusted by analyzing the interaction between the patient and the ventilator at different phases. A novel fuzzy control method of the ventilator support pressure is proposed in the pressure support ventilation mode. According to the fuzzy rules in this research, the plateau pressure can be obtained by the trigger sensitivity and the patient’s inspiratory effort. An experiment prototype of the ventilator is established to verify the accuracy of the pneumatic model and the validity of the mechanical ventilation strategies proposed in this article. In addition, through the discussion of the patient-ventilator asynchrony, the strategies for mechanical ventilation can be adjusted accordingly. The results of this research are meaningful for the clinical operation of mechanical ventilation. Besides, these results provide a theoretical basis for the future research on the intelligent control of ventilator and the automation of weaning process.