Neurally adjusted ventilatory assist: a new exploration for difficult weaning

ZusammenfassungDie logistischen und infektiologischen Besonderheiten und Erfordernisse in der Pandemie stellen die intensivmedizinischen Behandlungsteams vor außerordentliche Herausforderungen, die eine erfolgreiche Liberation von Patienten im prolongierten Weaning erschweren können. Gerade in der Pandemie gilt es daher, alle Potenziale zur Beatmungsentwöhnung und Dekanülierung von Patienten im prolongierten Weaning oder in der Langzeitbeatmung auszuschöpfen.Weaning-Zentren stellen Einheiten der intensivmedizinischen Betreuung mit besonderer Spezialisierung auf prolongiertes Weaning dar und sind integraler Bestandteil eines kontinuierlichen Versorgungskonzeptes dieser Patienten. Ein systematisches Weaning-Konzept in der Pandemie setzt strukturelle, personelle, apparative, infektiologische und hygienische Aspekte voraus.Im Mittelpunkt dieses Positionspapiers stehen als Ergänzung zur S2k-Leitlinie „Prolongiertes Weaning“ eine neue Klassifikation im prolongierten Weaning und zukünftig erforderliche Organisationsstrukturen für die Pandemie-Situation.Patienten der Kategorie A mit hohem Weaning-Potenzial bedürfen der strukturierten Respiratorentwöhnung in spezialisierten Weaning-Einheiten, um so die größtmögliche Chance auf erfolgreiches Weaning zu realisieren. Patienten der Kategorie B mit geringem oder aktuell nicht vorhandenem Weaning-Potenzial sollten verzögert nach einer Zwischenphase der weiteren Stabilsierung in einer außerklinischen Beatmungseinrichtung einen Weaning-Versuch erhalten. Patienten der Kategorie C ohne Weaning-Potenzial benötigen eine dauerhafte außerklinische Versorgung, alternativ eine palliativmedizinisch begleitete Beendigung der Beatmung. Die sich aus den 3 Kategorien ergebenden Aufgaben für die Weaning-Zentren werden im Positionspapier vertieft.Schließlich werden unter perspektivischer Betrachtung im Positionspapier folgende zukünftig denkbare Netzwerke und Register benannt: 1. lokal organisierte regionale Netzwerke von zertifizierten Weaning-Zentren, 2. ein zentrales, bundesweites Register der Weaning-Kapazitäten entsprechend dem DIVI-Register und 3. eine Registrierung der Patienten im schwierigen oder prolongierten Weaning.

DEVELOPMENT AND VALIDATION OF A CLINICAL DECISION-SUPPORT TOOL FOR PREDICTION OF WEANING OUTCOME ON ADMISSION TO THE ICU

Gender differences in patients starting long-term home mechanical ventilation due to obesity hypoventilation syndrome

Актуальність. Пацієнти з комбінованими формами дихальної недостатності часто мають довготривале чи навіть невдале відлучення від штучної вентиляції легень (ШВЛ). Мета дослідження: порівняти тривалість проведення ШВЛ, а також показники функціонування діафрагми при використанні технологій P-SIMV та BIPAP у пацієнтів на етапі відлучення від ШВЛ. Матеріали та методи. Проведено проспективне обсерваційне нерандомізоване когортне дослідження серед 27 пацієнтів з гострою дихальною недостатністю. До І (режим P-SIMV) та ІІ груп пацієнтів (режим BIPAP ) увійшло по 10 пацієнтів. Первинними точками оцінювання результатів лікування були тривалість проведення інвазивної ШВЛ; вторинними точками — амплітуда рухів обох куполів діафрагми, фракція стоншення діафрагми, виникнення декомпенсованого респіраторного чи змішаного ацидозу. Результати. Середня тривалість проведення ШВЛ у пацієнтів першої групи становила 14,14 ± 1,83 доби, у пацієнтів другої групи — 13,2 ± 2,56 доби (p = 0,32). Амплітуда рухів куполів діафрагми в першу добу дослідження становила в І групі пацієнтів 7,2 ± 1,8 мм, у ІІ групі — 6,8 ± 1,5 (p = 0,42); на 5-ту добу лікування цей показник вірогідно не відрізнявся між групами та в І групі зростав до 8,1 ± 2,1 мм, у ІІ — до 8,4 ± 1,9 мм (p = 0,12 та p = 0,89). Вже на 9-ту добу лікування амплітуда рухів правого купола діафрагми вірогідно (р = 0,04) відрізнялася у І групі пацієнтів щодо ІІ групи (9,0 ± 2,1 мм та 10,0 ± 1,3 мм відповідно) та щодо попереднього етапу обстеження (p = 0,05 та p = 0,04). Амплітуда рухів правого купола діафрагми залишалася на рівні понад 10 мм у ІІ групі пацієнтів і на 13-ту та 17-ту добу спостереження за пацієнтами. Висновки. Тривалість проведення ШВЛ у дітей з поєднанням обструктивного та рестриктивного типів дихальної недостатності в І та ІІ групах вірогідно не відрізнялася. Спонтанні дихальні зусилля були вірогідно вищими у пацієнтів ІІ групи починаючи з 9-ї доби порівняно з пацієнтами І групи.

Objective To evaluate the predictive performance of diaphragm thickening fraction (DTF) assessed by ultrasound in the feasibility of weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease (COPD). Methods Forty-three patients with COPD were enrolled for prospective study.All patients were ventilated mechanically for more than 48 hours and were expected to be weaned when they met clinical criteria in the intensive care unit from February 2015 to August 2015.Patients received a spontaneous breathing trial under pressure support for 1 h. At the end of spontaneous breathing trial, the right hemi-diaphragm was visualized in the zone of apposition using a 6-13 MHz linear ultrasound probe. Diaphragm thickness was recorded at end-inspiration(DTei) and end-expiration(DTee), and the DTF was calculated as percentage from the following formula: (DTei - DTee) / DTee. Also the rapid shallow breathing index (RSBI) was calculated. Patients meeting weaning criteria were extubated. Weaning successfully was defined as spontaneous breathing for >48 h without any form of ventilation support. Results Twenty-five patients were weaned successfully and failure of weaning was found in 18 patients. A significant differences in DTF(39.66±13.22)%vs.(23.84±8.85)%, P<0.05 and RSBI(62.74±26.05)vs.(98.89±35.44), P<0.05 were observed between patients with successful weaning and patients with failure. The sensitivity and specificity of DTF≥30 % for successful weaning were 84% and 83.88 %, respectively. The area under the receiver operating characteristic curve was 0.872(95 % CI: 0.759-0.985)for DTF. By comparison, when RSBI was ≤105, there was a sensitivity of 92 %, and a specificity of 38.89 % for determining successful weaning. The area under the receiver operating characteristic curve was 0.804(95 % CI: 0.669-0.940)for RSBI. Conclusions This study shows that in a cohort of COPD patients, the assessment of DTF using diaphragm ultrasound may be useful to predict success weaning or failure during spontaneous breathing trial. Key words: Ultrasound; Diaphragm; Chronic obstructive pulmonary disease; Mechanical ventilation; Weaning; Bedside; Critical ill; Predictive value

Background: The Rapid Shallow Breathing Index (RSBI) is widely used in weaning assessment. The threshold value of the RSBI is dependent on the patient cohort and the method used to measure it. The aims of this study were to establish a protocol for measuring the RSBI through mechanical ventilator monitoring and to simplify weaning assessment. Patients and methods: The study was conducted prospectively at Taichung Veterans General Hospital. Patients intending to discontinue mechanical ventilator use were enrolled. The RSBI was measured using 2 methods for each patient: 1) a conventional hand-held calibrated spirometry (C-RSBI), and 2) the RSBI calculated through mechanical ventilator monitoring (V-RSBI) under CPAP 5 cmH2O and a flow trigger. In addition, the ability to cough was scored semi-quantitatively. The performance of these parameters in predicting weaning failure and re-intubation within 72 hours was evaluated. Results: One hundred and eight patients (age: 66±17 years; M/F: 75/33; intubation days: 8.8±9.8) were enrolled. The C-RSBI (70±42) and V-RSBI (69±35) showed significantly good correlation (r=0.759, p＜0.001). The values of the RSBI were higher in the medical patients than in the surgical patients, but were not related to weaning failure. A poor ability to cough was a significant predictor of weaning failure. The rate of weaning failure was up to 18.2% in the patients with an ability to cough ≤3 and V-RSBI ≥60. Conclusions: The V-RSBI was measured accurately through the readout of the mechanical ventilator and its value was nearly equal to that of the C-RSBI. In combination with a non-invasive assessment of the ability to cough, V-RSBI was a simple method to assess patients with the intent to wean from the ventilator.

BackgroundAlthough the weaning classification based on the difficulty and duration of the weaning process has been evaluated in the different type of intensive care units (ICUs), little is known about clinical outcomes and validity among the three groups in medical ICU. The objectives of this study were to evaluate the clinical relevance of weaning classification and its association with hospital mortality in a medical ICU with a protocol-based weaning program.MethodsAll consecutive patients admitted to the medical ICU and requiring mechanical ventilation (MV) for more than 24 hours were prospectively registered and screened for weaning readiness by a standardized weaning program between July 2010 and June 2013. Baseline characteristics and outcomes were compared across weaning classifications.ResultsDuring the study period, a total of 680 patients were weaned according to the standardized weaning protocol. Of these, 457 (67%) were classified as simple weaning, 136 (20%) as difficult weaning, and 87 (13%) as prolonged weaning. Ventilator-free days within 28 days decreased significantly from simple to difficult to prolonged weaning groups (P < 0.001, test for trends). In addition, reintubation within 48 hours after extubation (P < 0.001) and need for tracheostomy during the weaning process (P < 0.001) increased significantly across weaning groups. Finally, ICU (P < 0.001), post-ICU (P = 0.001), and hospital (P < 0.001) mortalities significantly increased across weaning groups. In a multiple logistic regression model, prolonged weaning but not difficult weaning was still independently associated with ICU (adjusted OR 8.265, 95% CI 3.484–19.605, P < 0.001), and post-ICU (adjusted OR 3.180, 95% CI 1.349–7.497, P = 0.005), and hospital (adjusted OR 5.528, 95% CI 2.801–10.910, P < 0.001) mortalities.ConclusionsWeaning classification based on the difficulty and duration of the weaning process may provide prognostic information for mechanically ventilated patients who undergo the weaning process.

Patients with a tracheostomy and difficult weaning from invasive mechanical ventilation constitute a challenging problem in critical care. An increased duration of ventilation may lead to diaphragmatic dysfunction and a noninvasive assessment of the diaphragm, such as ultrasound, attracts interest in the clinical practice. We evaluated the relationship of ultrasound-derived indices with weaning outcome and with established indices of respiratory strength and load in subjects who are tracheostomized and undergoing weaning. This prospective study was conducted at an academic ICU in Greece. Twenty subjects with tracheostomy and difficult weaning, during a spontaneous breathing trial, underwent time synchronous diaphragmatic sonography and esophageal manometry, to assess diaphragmatic excursion and thickening fraction, esophageal and transdiaphragmatic pressures, pressure-time product of the esophageal pressure, and maximum inspiratory pressure. The primary outcome was liberation from mechanical ventilation at 48 h. The relationship of diaphragmatic ultrasound with esophageal pressure-derived indices was also evaluated. Weaning from invasive ventilation failed in 10 subjects. Diaphragmatic excursion exhibited a significant difference between weaning success and failure (1.34 ± 0.56 versus 0.79 ± 0.44; P = .044), a strong correlation with transdiaphragmatic pressure (r = 0.7, P = .02), and a moderate correlation with the pressure-time product of the esophageal pressure (r = 0.65, P = .02) and the maximum inspiratory pressure (r = 0.66, P = .02). Transdiaphragmatic pressure presented the highest area under the curve (0.97). However, when transdiaphragmatic pressure was compared with diaphragmatic excursion (area under the curve, 0.84) for predictive accuracy, no significant difference was found. Diaphragmatic excursion is a valuable tool for the assessment of diaphragmatic strength, respiratory load, and weaning prediction.

To identify the clinical and physiological factors associated with successful weaning from mechanical ventilation (MV) in patients with acute respiratory failure (ARF) treated in the Emergency department, and to evaluate their short-term prognosis. This retrospective study analyzed data from 248 ARF patients who underwent MV in the Emergency department from July 2021 to June 2024. Patients were categorized into weaning success and failure groups based on their ability to maintain spontaneous breathing for over 48 hours post-extubation. Collected variables included demographic characteristics, body mass index, MV duration, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, blood gas parameters, and diaphragm function metrics. Multivariate logistic regression was used to identify independent predictors of weaning success. Among the 248 patients, 165 (66.5%) were successfully weaned. Independent predictors of successful weaning included shorter MV duration, lower APACHE II scores, higher tidal volumes, and lower respiratory rates during spontaneous breathing trials. Diaphragmatic excursion was negatively associated with weaning failure, as was arterial oxygen partial pressure (PaO2). Patients in the failure group had longer hospital stays and higher rates of complications, invasive interventions, and readmissions (all P<0.05). Weaning success in ARF patients managed in the Emergency department is influenced by a combination of clinical severity, ventilatory parameters, and diaphragm function. Recognition of these factors may aid in optimizing weaning strategies and improving patient prognosis.

Rationale:Many factors contribute to a complicated postoperative course following difficult weaning off a ventilator after lung transplantation.Patient concerns:A female patient underwent a successful surgery but received a size-mismatched lung graft. The graft had been pruned before transplantation. She experienced delayed ventilator weaning 3 days after lung transplantation.Diagnoses:A postoperative X-ray revealed a normal mediastinal structure and diaphragm position. Diaphragmatic function was assessed by diaphragm electromyography (EMGdi) via esophageal and surface electrodes. EMGdi showed decreased left compound motor action potentials (CMAPs), prolonged left phrenic nerve conduction time (PNCT), failure to induce right CMAPs and PNCT under bilateral magnetic stimulation, and right phrenic nerve injury.Interventions:She was treated with neural nutritional support and prescribed rehabilitation measures such as strengthening limb activities on the bed.Outcomes:The patient finally achieved satisfactory outcomes after an early diagnosis and medical interventions.Lessons:Lung size mismatch before transplantation and phrenic nerve injury during surgery should be avoided wherever possible.

Objective To investigate the risk factors of weaning failure in patients with chronic heart failure and preserved ejection fraction. Methods A total of 126 patients with chronic heart failure and preserved ejection fraction hospitalized in our hospital were retrospectively analyzed. The patients received ventilator-assisted ventilation and drug treatment, and were divided into the successful weaning group (n= 96) and failed weaning group (n=30). The associated influencing factors the weaning failure was determined. Results The findings of univariate analysis showed that there were statistically significant differences in diabetes mellitus, hypertension, hypercapnia, TG, Sc, SUA, cTnI, NT-proBNP, VE, and VE/VA between the successful weaning group and failed weaning group (P<0.05). The unconditional logistic regression analysis showed that diabetes, hypertension, hypercapnia, TG, NT-proBNP, VE and VE/VA were the risk factors for weaning failure. Conclusion There are many risk factors for the weaning failure in patients with chronic heart failure with preserved ejection fraction. Before weaning, it is necessary to fully judge the weaning time, so as to improve the accuracy of weaning and prognosis. Key words: Heart failure; Preserved ejection fraction; Weaning; Logistic regression analysis

Background and objective Delirium is an important predictor of negative clinical outcomes in intensive care unit (ICU), including prolonged mechanical ventilation (MV). However, delirium has not yet proven to be directly linked to weaning difficulties. The objective of this cohort study was to evaluate the association between delirium, as observed on the day of the weaning trial, and subsequent weaning outcomes in medical patients. Methods This is a retrospective analysis with prospectively collected data on weaning from mechanical ventilation (MV) and delirium, as assessed by bedside ICU nurses using the Confusion Assessment Method for the ICU (CAM-ICU) between October 2011 and September 2013. Results During the study period, a total of 393 patients with MV support underwent a spontaneous breathing trial (SBT) according to the standardized protocol. Of these patients, 160 (40.7%) were diagnosed with delirium on the day of the first SBT. Patients without delirium were more successfully extubated than those with delirium (81.5% vs 69.4%, P = 0.005). Delirium was found to be associated with final weaning outcomes, including difficult (OR 1.962, 95% CI 1.201–3.205) and prolonged weaning (OR 2.318, 95% CI 1.272–4.226) when simple weaning was used as a reference category. After adjusting for potential confounding factors, delirium was still significantly associated with difficult weaning (adjusted OR 2.073, 95% CI 1.124–3.822), but not with prolonged weaning (adjusted OR 2.001, 95% CI 0.875–4.575). Conclusion Delirium, as assessed by the CAM-ICU at the time of first weaning trial, was significantly associated with weaning difficulties in medical patients.

Difficult weaning is fortunately a rare occurrence in mechanically ventilated patients in ICU. When faced with this problem, a vast number of factors must be carefully considered simultaneously: physiological adjustment, technical problems (tubing, circuit resistances, . . .) [13]. The most promising approach to difficult weaning to date centers on the respiratory muscle function which represents the most common factor allowing weaning success or failure.

Background Weaning from mechanical ventilation (MV( and timing of extubation are crucial components in the postoperative management of cardiac surgery as altered respiratory mechanics and positive pressure ventilation may have significant influence on hemodynamics. Aim: To evaluate risk factors for failure of weaning from mechanical ventilation after pediatric cardiac surgery and to assess the frequency of phrenic nerve injury. Methodology This Cohort study included medical records of 101 children admitted consecutively to Pediatric post-cardiac surgery ICU in Academy of Cardiovascular surgery in Ain Shams university Hospitals between April, 2020 and April, 2021, who had undergone heart surgery. The patients were divided into two groups : - successefully weaned group. - Difficult to wean group. Diaphragmatic ultrasound was done for every difficult weaning patient to assess diaphragmatic paralysis. Result: Age (P &amp;lt; 0.001), Weight (P &amp;lt; 0.001), volum intake (P &amp;lt; 0.001), systolic blood pressure (P = 0.017), Diastolic blood pressure (P = 0.004), were significantly lower in patients who showed difficult weaning compared to patients with successful weaning. Furthermore operation time (P &amp;lt; 0.001), use of noradrenaline (P = 0.019), use of adrenaline ( P = 0.017), use of Milirinon ( P = 0.003), respiratory rate ( P = 0.003), inotropic support (P = 0.001), positive fluid balance (P &amp;lt; 0.001), heart failure, renal failure, Pulmonary complications, need of pace maker, sepsis ( P &amp;lt; 0.001), diaphragmatic paralysis ( P &amp;lt; 0.001), transposition of great arteries operations ( P = 0.009), were significantly higher in patients who showed difficult weaning compared to patients with successful weaning. While use of dobutamine, discharge with open chest, reoperation, transfusion &amp;gt; 50 ml / kg, urine output, reoperation bleeding and any operation other than atrial septal defect, transposition of great arteries all did not affect weaning difficulty. Conclusion younger age, operation time, as well as sepsis were the best predictors for difficulty of weaning.

Muscle weakness, defined by the Medical Research Council scale, has been associated with delay in mechanical ventilation weaning. In this study, we evaluated handgrip strength as a prediction tool in weaning outcome. This was a 1-y prospective study in 2 ICUs in 2 university hospitals. Adult patients who were on mechanical ventilation for at least 48 h and eligible for mechanical ventilation weaning were screened for inclusion. Handgrip strength was evaluated using a handheld dynamometer before each spontaneous breathing trial (SBT). Attending physicians were unaware of handgrip strength and decided on extubation according to guidelines. Eighty-four subjects were included (median age 66 [53-79] y, with a median Simplified Acute Physiology Score II of 49 [37-63]). At the first evaluation, median handgrip strength was significantly associated with weaning outcome as defined by international guidelines: simple (20 [12-26] kg), difficult (12 [6-21] kg), or prolonged (6 [3-11] kg) weaning (P = .008). Time to liberation from mechanical ventilation and ICU stay were significantly longer for subjects classified as having muscle weakness according to the handgrip strength-derived definition (P = .02 and P = .03, respectively). In multivariate analysis, known history of COPD (odds ratio [OR] 5.48, 95% CI 1.44-20.86, P = .01), sex (OR 6.16, 95% CI 1.64-23.16, P = .007), and handgrip strength at the first SBT (OR 0.89, 95% CI 0.85-0.97, P = .004) were significantly associated with difficult or prolonged weaning. Extubation failure, as defined by re-intubation or unscheduled noninvasive ventilation within 48 h after extubation, occurred 14 times after 92 attempts, leading to an extubation failure rate of 15%. No association was found between handgrip strength and extubation outcome. Muscle weakness, assessed by handgrip strength, is associated with difficult or prolonged mechanical ventilation weaning and ICU stay, but not with extubation outcome.