[Weaning from prolonged mechanical ventilation on a specialised weaning unit: a retrospective comparison of patients with and without SARS-CoV-2 infection]. / Entwöhnung von der Langzeitbeatmung nach ARDS auf einer spezialisierten Weaning-Einheit ­ ein retrospektiver Vergleich von Patienten mit und ohne SARS-CoV-2 Infektion.

BACKGROUND: Available data on patients requiring prolonged mechanical ventilation due to severe COVID-19 are sparse. Here we compare patients with ARDS related or not related to SARS-CoV-2 infection treated in a specialised weaning unit. METHODS: A retrospective analysis of all patients with prolonged mechanical ventilation associated with an ARDS admitted from the 21st November 2013 to the 23rd July 2021 to the weaning unit of the University Hospital RWTH Aachen was performed. ARDS patients with COVID-19 (cARDS) were compared to patients with ARDS not related to COVID-19 (ncARDS). RESULTS: In total, n=129 patients in prolonged need for mechanical ventilation after ARDS were treated in the weaning unit, of whom n=38 had been suffering from ARDS related to COVID-19. Both patients groups were similar in terms of demographic parameters, underlying chronic illnesses, severity of ARDS and the duration of mechanical ventilation before being admitted to the weaning unit. During ICU stay, prone positioning and therapy with systemic corticosteroids was used more frequently in cARDS patients. Furthermore, therapy with vasoconstrictors was needed more often (cARDS: 42.1% vs. ncARDS 12.1%; p=0.0003) and urinary output was lower (cARDS: 1980 ml vs. ncARDS: 2600 ml; p=0.0037) in this patient group. The clinical course of the weaning process was similar in patients with cARDS and ncARDS, there were no significant differences in the occurrence of complications and the duration of mechanical ventilation. There were n=5 deaths (13.2%) in the cARDS and n=15 deaths (16.5%) in the ncARDS group. After hospital discharge, n=4 patients required non-invasive ventilation whereas out-of-hospital invasive ventilation was only necessary in one patient (all in the ncARDS group). CONCLUSION: After having survived the acute phase, the disease prognosis of patients with severe COVID-19 is favourable and most patients can be successfully weaned from mechanical ventilation. In addition, there were only minor differences compared to patients with ARDS unrelated to COVID-19.

Inhalation therapies in COPD - adverse drug reactions impact on emergency department presentations.

PURPOSE: Inhaled drugs have been cornerstones in the treatment of chronic obstructive pulmonary disease (COPD) for decades and show a high prescription volume. Due to the local application, drug safety issues of these therapies are often underestimated by professionals and patients. Data about adverse drug reactions (ADRs) caused by inhaled therapy in patients with COPD and polypharmacy are rare. We aimed to analyze the use and relevance of inhaled therapies in those patients in relation to ADR complaints, which were severe enough to warrant presentation to the emergency department. METHODS: Emergency department cases due to suspected ADRs of the ADRED database (n = 2939, "Adverse Drug Reactions in Emergency Departments"; DRKS-ID: DRKS00008979, registration date 01/11/2017) were analyzed for inhaled drugs in patients with COPD. ADRs in cases with overdosed inhaled drugs were compared to non-overdosed cases. ADRs, potentially caused by inhaled drugs, were evaluated, clustered into complexes, and assessed for association with inhaled drug classes. RESULTS: Of the 269 included COPD cases, 67% (n = 180) received inhaled therapy. In 16% (n = 28), these therapies were overdosed. Overdosed cases presented the complexes of malaise and local symptoms more frequently. Related to the use of inhaled anticholinergics, local (dysphagia-like) and related to inhaled beta-2 agonists, local (dysphagia-like) and sympathomimetic-like ADRs presented more frequently. CONCLUSION: Overdosed inhaled therapies in patients with COPD lead to relevant ADRs and impact on emergency room presentations. These are rarely associated to inhaled therapy by healthcare professionals or patients. Due to the high volume of inhaled drug prescriptions, pharmacovigilance and patient education should be more focused in patients with COPD. German Clinical Trial Register: DRKS-ID: DRKS00008979.

Emergency Department Visits Due to Dyspnea: Association with Inhalation Therapy in COPD and Cases with Adverse Drug Reactions.

Purpose: Dyspnea is a leading symptom of COPD that causes presentations in emergency departments or negatively impacts on them. Guideline-based inhalation therapies are intended to reduce dyspnea in COPD patients. This study analyzed how common guideline recommended inhalation therapy regimens are occurring in clinical practice among COPD patients presenting to emergency departments due to adverse drug reactions in polytherapy using data of the German ADRED database. Patients and Methods: In total, 269 COPD cases were identified. In a further analysis, all cases were analyzed for documented GOLD stage and guideline-recommended inhalation therapy for COPD. Dyspnea and other symptoms identified during ED presentation were analyzed and compared between patients who did and did not receive the guideline's recommended inhalation therapy. Results: In this observation, 41% (n = 46) of all 112 cases with a documented COPD and GOLD stage received an underdosed therapy according to current guidelines. Dyspnea was the most common identified symptom (32%, n = 36) in this cohort and occurred more often in patients who received an underdosage of inhalation therapy (p < 0.01). Conclusion: Patients with COPD presenting to ED with ADRs show a high rate of non-guideline-recommended inhalation therapy and present more often with dyspnea compared to those COPD patients who received an adequate dosing of inhalation therapy.

Six Months Follow-Up of Patients with Invasive Mechanical Ventilation due to COVID-19 Related ARDS.

Although patients who recovered from acute coronavirus disease 2019 (COVID-19) may have prolonged disabilities, follow-up data of those who have survived COVID-19 related acute respiratory distress syndrome (ARDS) is still very scarce. Therefore, COVID-19-ARDS survivors requiring invasive mechanical ventilation (IMV) were followed six months after discharge. Pulmonary function tests (PFTs), 6-min walk test (6MWT) and echocardiography were performed. Quality of life (QoL), depression and anxiety were assessed using validated questionnaires. Patients were compared based on respiratory mechanics and CT-phenotype during intensive care unit (ICU) stay. Eighteen patients were included (61 ± 7 years; ICU-stay: 34 ± 16 days; IMV: 30 ± 15 days). At follow-up (197 ± 15 days after discharge), PFTs did not reveal significant limitations (VC: 92 ± 16%; FEV1: 92 ± 20%; DLco/VA: 81 ± 16%). Cardiac systolic function was normal in all patients, but 50% of them had diastolic dysfunction. 6MWT was under the lower limit of normal in only two patients. Eight patients (44%) reported tiredness, six (33%) suffered from fatigue and one patient (6%) had depression and anxiety. Surprisingly, patients with worse respiratory mechanics during IMV reported fewer symptoms and less exertional dyspnea at follow-up. In conclusion, patients with COVID-19-ARDS have the possibility to fully recover regarding pulmonary function and exercise capacity, which seems to be independent of disease severity during ICU stay.

Broncho-alveolar lavage in patients with acute respiratory distress syndrome due to COVID-19.

As data about microbiological testing and the cellular composition of the broncho-alveolar lavage (BAL) fluid in patients ventilated due to coronavirus disease 2019 (COVID-19) are lacking, this was investigated in a retrospective analysis (n = 58). Co-infection with pathogens was detected in 31 patients, whereas the analysis of BAL cellularity showed an increased total cell count and an alveolitis dominated by neutrophils. None of the physicians performing bronchoscopies in COVID-19 patients had serological evidence of severe acute respiratory syndrome coronavirus 2 infection.

Follow up of patients with severe coronavirus disease 2019 (COVID-19): Pulmonary and extrapulmonary disease sequelae.

BACKGROUND: Since December 2019 the novel coronavirus disease 2019 (COVID-19) has been burdening all health systems worldwide. However, pulmonary and extrapulmonary sequelae of COVID-19 after recovery from the acute disease are unknown. MATERIAL AND METHODS: Hospitalized COVID-19 patients not requiring mechanical ventilation were included and followed 6 weeks after discharge. Body plethysmography, lung diffusion capacity (DLco), blood gas analysis (ABG), 6-min walk test (6MWT), echocardiography, and laboratory tests were performed. Quality of life (QoL), depression, and anxiety were assessed using validated questionnaires. RESULTS: 33 patients with severe disease were included. Patients were discharged without prophylactic anticoagulation. At follow-up there were no thromboembolic complications in any patient. 11 patients (33%) had dyspnea, 11 (33%) had cough, and 15 (45%) suffered from symptoms of fatigue. Pulmonary function tests including ABG did not reveal any limitations (TLC: median=94% of predicted {IQR:85-105}; VC: 93% {78-101}; FEV1: 95% {72-103}; FEV1/FVC 79% {76-85}; PaO2: 72 mmHg {67-79}; PaCO2: 38 mmHg {35-38}), except for slightly reduced DLco (77% {69-95}). There were no echocardiographic impairments. 6MWT distance was reduced in most patients without oxygen desaturation. According to standardized questionnaires, patients suffered from reduced QoL, mainly due to decreased mobility (SGRQ activity score: 54 {19-78}). There were no indicators for depression or anxiety (PHQ-9: 7 {4-11}, GAD-7: 4 {1-9}, respectively). CONCLUSIONS: Hospitalized patients with severe COVID-19, who did not require mechanical ventilation, are unlikely to develop pulmonary long-term impairments, thromboembolic complications or cardiac impairments after discharge but frequently suffer from symptoms of fatigue.

Influence of weaning methods on the diaphragm after mechanical ventilation in a rat model.

BACKGROUND: Mechanical ventilation (MV) is associated with diaphragm weakness, a phenomenon termed ventilator-induced diaphragmatic dysfunction. Weaning should balance diaphragmatic loading as well as prevention of overload after MV. The weaning methods pressure support ventilation (PSV) and spontaneous breathing trials (SBT) lead to gradual or intermittent reloading of a weak diaphragm, respectively. This study investigated which weaning method allows more efficient restoration of diaphragm homeostasis. METHODS: Rats (n = 8 per group) received 12 h of MV followed by either 12 h of pressure support ventilation (PSV) or intermittent spontaneous breathing trials (SBT) and were compared to rats euthanized after 12 h MV (CMV) and to acutely euthanized rats (CON). Force generation, activity of calpain-1 and caspase-3, oxidative stress, and markers of protein synthesis (phosphorylated AKT to total AKT) were measured in the diaphragm. RESULTS: Reduction of diaphragmatic force caused by CMV compared to CON was worsened with PSV and SBT (both p < 0.05 vs. CON and CMV). Both PSV and SBT reversed oxidative stress and calpain-1 activation caused by CMV. Reduced pAKT/AKT was observed after CMV and both weaning procedures. CONCLUSIONS: MV resulted in a loss of diaphragmatic contractility, which was aggravated in SBT and PSV despite reversal of oxidative stress and proteolysis.

Sevoflurane exposure prevents diaphragmatic oxidative stress during mechanical ventilation but reduces force and affects protein metabolism even during spontaneous breathing in a rat model.

BACKGROUND: Ventilator-induced diaphragmatic dysfunction is associated with the generation of oxidative stress, enhanced proteolysis, autophagy and reduced protein synthesis in the diaphragm. Sevoflurane is a common operating room anesthetic and can be used in the intensive care medicine as well. Besides its anesthetic properties, its use in cardiac ischemia-reperfusion models can maintain protein synthesis and inhibit generation of reactive oxygen species, if used at the beginning of heart surgery. This study has been performed on the hypothesis that sevoflurane might protect against ventilator-induced diaphragmatic dysfunction by preventing the production of oxidative stress. METHODS: Four-month-old, male Sprague-Dawley rats sedated with sevoflurane (minimal alveolar concentration = 1) were either mechanically ventilated (MV) for 12 hours (n = 8) or allowed to breathe spontaneously (SB) for 12 hours (n = 8). An acutely anesthetized group was used as a control (Con) group (n = 8). After euthanization, diaphragmatic contractile properties, fiber cross-sectional areas, proteolysis (calpain-1 and caspase-3), and oxidative stress (lipid peroxidation, protein oxidation) were examined. After testing for normality, 1-way or 2-way analysis of variance with the Dunnett post hoc test was used to test for significance. RESULTS: The diaphragm contractile force was similarly reduced at all stimulation frequencies in the SB and MV groups compared with controls. Markers of oxidative stress and fiber cross-sectional areas were unaltered between Con and SB/MV, respectively. The calcium-dependent proteases (calpain-1 and caspase-3) were enhanced in the MV group. The p-AKT/AKT ratio and p-FoxO1/FoxO1 ratio were significantly and similarly reduced after sevoflurane exposure in the SB and MV group compared with Con group. CONCLUSIONS: Exposure to sevoflurane did not induce oxidative stress. It led to reduction in diaphragmatic force. In the MV group, sevoflurane led to the activation of atrophy signaling pathways. These findings are of particular importance for clinical utilization in intensive care units and question its use, especially during the phases of SB.

Recovery of diaphragm function following mechanical ventilation in a rodent model.

BACKGROUND: Mechanical ventilation (MV) induces diaphragmatic muscle fiber atrophy and contractile dysfunction (ventilator induced diaphragmatic dysfunction, VIDD). It is unknown how rapidly diaphragm muscle recovers from VIDD once spontaneous breathing is restored. We hypothesized that following extubation, the return to voluntary breathing would restore diaphragm muscle fiber size and contractile function using an established rodent model. METHODS: Following 12 hours of MV, animals were either euthanized or, after full wake up, extubated and returned to voluntary breathing for 12 hours or 24 hours. Acutely euthanized animals served as controls (each n = 8/group). Diaphragmatic contractility, fiber size, protease activation, and biomarkers of oxidative damage in the diaphragm were assessed. RESULTS: 12 hours of MV induced VIDD. Compared to controls diaphragm contractility remained significantly depressed at 12 h after extubation but rebounded at 24 h to near control levels. Diaphragmatic levels of oxidized proteins were significantly elevated after MV (p = 0.002) and normalized at 24 hours after extubation. CONCLUSIONS: These findings indicate that diaphragm recovery from VIDD, as indexed by fiber size and contractile properties, returns to near control levels within 24 hours after returning to spontaneous breathing. Besides the down-regulation of proteolytic pathways and oxidative stress at 24 hours after extubation further repairing mechanisms have to be determined.

Sedation using propofol induces similar diaphragm dysfunction and atrophy during spontaneous breathing and mechanical ventilation in rats.

BACKGROUND: Mechanical ventilation is crucial for patients with respiratory failure. The mechanical takeover of diaphragm function leads to diaphragm dysfunction and atrophy (ventilator-induced diaphragmatic dysfunction), with an increase in oxidative stress as a major contributor. In most patients, a sedative regimen has to be initiated to allow tube tolerance and ventilator synchrony. Clinical data imply a correlation between cumulative propofol dosage and diaphragm dysfunction, whereas laboratory investigations have revealed that propofol has some antioxidant properties. The authors hypothesized that propofol reduces markers of oxidative stress, atrophy, and contractile dysfunction in the diaphragm. METHODS: Male Wistar rats (n = 8 per group) were subjected to either 24 h of mechanical ventilation or were undergone breathing spontaneously for 24 h under propofol sedation to test for drug effects. Another acutely sacrificed group served as controls. After sacrifice, diaphragm tissue was removed, and contractile properties, cross-sectional areas, oxidative stress, and proteolysis were examined. The gastrocnemius served as internal control. RESULTS: Propofol did not protect against diaphragm atrophy, oxidative stress, and protease activation. The decrease in tetanic force compared with controls was similar in the spontaneous breathing group (31%) and in the ventilated group (34%), and both groups showed the same amount of muscle atrophy. The gastrocnemius muscle fibers did not show atrophy. CONCLUSIONS: Propofol does not protect against ventilator-induced diaphragmatic dysfunction or oxidative injury. Notably, spontaneous breathing under propofol sedation resulted in the same amount of diaphragm atrophy and dysfunction although diaphragm activation per se protects against ventilator-induced diaphragmatic dysfunction. This makes a drug effect of propofol likely.

Prolonged mechanical ventilation alters the expression pattern of angio-neogenetic factors in a pre-clinical rat model.

OBJECTIVE: Mechanical ventilation (MV) is a life saving intervention for patients with respiratory failure. Even after 6 hours of MV, diaphragm atrophy and dysfunction (collectively referred to as ventilator-induced diaphragmatic dysfunction, VIDD) occurs in concert with a blunted blood flow and oxygen delivery. The regulation of hypoxia sensitive factors (i.e. hypoxia inducible factor 1α, 2α (HIF-1α,-2α), vascular endothelial growth factor (VEGF)) and angio-neogenetic factors (angiopoietin 1-3, Ang) might contribute to reactive and compensatory alterations in diaphragm muscle. METHODS: Male Wistar rats (n = 8) were ventilated for 24 hours or directly sacrificed (n = 8), diaphragm and mixed gastrocnemius muscle tissue was removed. Quantitative real time PCR and western blot analyses were performed to detect changes in angio-neogenetic factors and inflammatory markers. Tissues were stained using Isolectin (IB 4) to determine capillarity and calculate the capillary/fiber ratio. RESULTS: MV resulted in up-regulation of Ang 2 and HIF-1α mRNA in both diaphragm and gastrocnemius, while VEGF mRNA was down-regulated in both tissues. HIF-2α mRNA was reduced in both tissues, while GLUT 4 mRNA was increased in gastrocnemius and reduced in diaphragm samples. Protein levels of VEGF, HIF-1α, -2α and 4 did not change significantly. Additionally, inflammatory cytokine mRNA (Interleukin (IL)-6, IL-1ß and TNF α) were elevated in diaphragm tissue. CONCLUSION: The results demonstrate that 24 hrs of MV and the associated limb disuse induce an up-regulation of angio-neogenetic factors that are connected to HIF-1α. Changes in HIF-1α expression may be due to several interactions occurring during MV.