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Patients with uncontrolled hypertension are at increased risk of complications during general anaesthesia but the number of patients whose surgery is delayed or cancelled due to hypertension remains unknown. Prospective, regional multicentre service evaluations were performed on consecutive patients undergoing elective surgery before and after the publication of new guidelines from the Association of Anaesthetists and the British Hypertensive Society. The aim was to quantify the number of operations cancelled due to hypertension alone and to assess impact of the guidelines on cancellation rates. In October 2013 (before the publication of the guidelines), 1.37% (95%CI 0.69–2.11%) of patients listed for elective surgery were cancelled solely due to raised blood pressure. This reduced significantly to 0.54% (95%CI 0.20–0.92%, p < 0.001) in 2018. There was a significant reduction in inappropriate cancellations for stage 1 or 2 hypertension from 2013 to 2018 (72 vs. 14, respectively, p < 0.001) in keeping with the recommendations in the guidelines. Furthermore, the number of patients being referred back to primary care for the management of hypertension reduced from 2013 to 2018 (85 vs. 30, respectively, p < 0.001). Our data suggest achievement of three major outcomes: reduced surgical cancellations due to hypertension alone; improved detection of significant hypertension before elective surgery; and reduced referral back to primary care from hospital for hypertension management. To the best of our knowledge, this is the first time the successful implementation of guidelines from the Association of Anaesthetists has been assessed on such a broad scale. Our data indicate that these guidelines have been effectively implemented in both primary and secondary care, which is likely to have made a positive psychosocial, physical and economic impact on patients and the NHS.

A number of studies have highlighted physiological data from the first surge in critically unwell Covid-19 patients but there is a paucity of data describing emerging variants of SARS-CoV-2, such as B.1.1.7. We compared ventilatory parameters, biochemical and physiological data and mortality between the first and second COVID-19 surges in the United Kingdom, where distinct variants of SARS-CoV-2 were the dominant stain. We performed a retrospective cohort study investigating critically unwell patients admitted with COVID-19 across three tertiary regional ICUs in London, UK. Of 1782 adult ICU patients screened, 330 intubated and ventilated patients diagnosed with COVID-19 were included. In the second wave where B.1.1.7 variant was the dominant strain, patients were had increased severity of ARDS whilst compliance was greater (p

Cellular stress or injury induces release of endogenous danger signals such as ATP, which plays a central role in activating immune cells. ATP is essential for the release of nonclassically secreted cytokines such as IL-1β but, paradoxically, has been reported to inhibit the release of classically secreted cytokines such as TNF. Here, we reveal that ATP does switch off soluble TNF (17 kDa) release from LPS-treated macrophages, but rather than inhibiting the entire TNF secretion, ATP packages membrane TNF (26 kDa) within microvesicles (MVs). Secretion of membrane TNF within MVs bypasses the conventional endoplasmic reticulum- and Golgi transport-dependent pathway and is mediated by acid sphingomyelinase. These membrane TNF-carrying MVs are biologically more potent than soluble TNF in vivo, producing significant lung inflammation in mice. Thus, ATP critically alters TNF trafficking and secretion from macrophages, inducing novel unconventional membrane TNF signaling via MVs without direct cell-to-cell contact. These data have crucial implications for this key cytokine, particularly when therapeutically targeting TNF in acute inflammatory diseases.-Soni, S., O'Dea, K. P., Tan, Y. Y., Cho, K., Abe, E., Romano, R., Cui, J., Ma, D., Sarathchandra, P., Wilson, M. R., Takata, M. ATP redirects cytokine trafficking and promotes novel membrane TNF signaling via microvesicles.

Rationale: Mechanical ventilation is a mainstay of intensive care but contributes to the mortality of patients through ventilator induced lung injury. Extracellular Cyclophilin A is an emerging inflammatory mediator and metalloproteinase inducer, and the gene responsible for its expression has recently been linked to COVID-19 infection. Objectives: Here we explore the involvement of extracellular Cyclophilin A in the pathophysiology of ventilator-induced lung injury. Methods: Mice were ventilated with low or high tidal volume for up to 3 hours, with or without blockade of extracellular Cyclophilin A signalling, and lung injury and inflammation were evaluated. Human primary alveolar epithelial cells were exposed to in vitro stretch to explore the cellular source of extracellular Cyclophilin A, and Cyclophilin A levels were measured in bronchoalveolar lavage fluid from acute respiratory distress syndrome patients, to evaluate clinical relevance. Measurements and Main Results: High tidal volume ventilation in mice provoked a rapid increase in soluble Cyclophilin A levels in the alveolar space, but not plasma. In vivo ventilation and in vitro stretch experiments indicated alveolar epithelium as the likely major source. In vivo blockade of extracellular Cyclophilin A signalling substantially attenuated physiological dysfunction, macrophage activation and matrix metalloproteinases. Finally, we found that patients with acute respiratory distress syndrome showed markedly elevated levels of extracellular Cyclophilin A within bronchoalveolar lavage. Conclusions: Cyclophilin A is upregulated within the lungs of injuriously ventilated mice (and critically ill patients), where it plays a significant role in lung injury. Extracellular Cyclophilin A represents an exciting novel target for pharmacological intervention.

Emerging data suggest that patients with certain comorbidities requiring intensive care unit (ICU) admission for COVID-19 have a poor prognosis. This report describes a case of a patient with multiple comorbidities who contracted COVID-19 pneumonitis but was successfully weaned off invasive mechanical ventilation after 118 days, despite his admission being complicated by recurrent septic episodes and requirement for advanced cardiovascular support and renal replacement therapy. Of note, our patient received three courses of steroids in total during his ICU stay,and current literature strongly supports the use of steroids in critically unwell patients with COVID-19. To the best of our knowledge, this is the longest reported ventilated time and intensive care/hospital stay for a surviving patient with COVID-19 and highlights the importance of allowing sufficient time for clinical interventions to take effect, even when the prognosis appears bleak.

A high incidence of pancreatitis in COVID-19 has been reported. Although a high proportion of critically unwell patients with COVID-19 have raised serum amylase levels, this does not necessarily reflect acute pancreatitis or a clinically important pancreatic injury.

Despite advances in the pathophysiology of chronic obstructive pulmonary disease (COPD), there is a distinct lack of biochemical markers to aid clinical management. Microvesicles (MVs) have been implicated in the pathophysiology of inflammatory diseases including COPD, but their association to COPD disease severity remains unknown. We analyzed different MV populations in plasma and bronchoalveolar lavage fluid (BALF) taken from 62 patients with mild to very severe COPD (51% male; mean age: 65.9 yr). These patients underwent comprehensive clinical evaluation (symptom scores, lung function, and exercise testing), and the capacity of MVs to be clinical markers of disease severity was assessed. We successfully identified various MV subtype populations within BALF [leukocyte, polymorphonuclear leukocyte (PMN; i.e., neutrophil), monocyte, epithelial, and platelet MVs] and plasma (leukocyte, PMN, monocyte, and endothelial MVs) and compared each MV population to disease severity. BALF neutrophil MVs were the only population to significantly correlate with the clinical evaluation scores including forced expiratory volume in 1 s, modified Medical Research Council dyspnea score, 6-min walk test, hyperinflation, and gas transfer. BALF neutrophil MVs, but not neutrophil cell numbers, also strongly correlated with BODE index. We have undertaken, for the first time, a comprehensive evaluation of MV profiles within BALF/plasma of COPD patients. We demonstrate that BALF levels of neutrophil-derived MVs are unique in correlating with a number of key functional and clinically relevant disease severity indexes. Our results show the potential of BALF neutrophil MVs for a COPD biomarker that tightly links a key pathophysiological mechanism of COPD (intra-alveolar neutrophil activation) with clinical severity/outcome.

Background: Microvesicles (MV) play important roles in mediating intra-alveolar inflammation during acute lung injury. We investigated the MV profiles within bronchoalveolar lavage fluid (BALF) in patients undergoing lung transplantation and assessed relationship to the development of primary graft dysfunction (PGD). Methods: Lung transplant patients underwent bronchoscopy after completion of surgery and BALF samples (n=31) were analysed by flow cytometry for MVs derived from leucocytes (CD45+), neutrophils (CD66b+/CD11b+), monocytes (CD45+/CD14+), alveolar macrophages (CD206+/CD71+), platelets (CD31+/42b+) and epithelial (EpCAM+/T1α+) cells. MV numbers were correlated to clinical outcomes including hypoxia and development of PGD. Results: Various MV subpopulations were identified in BALF. Neutrophil-derived MVs were the largest population (10,548 (3,925-51,529)) compared to leucocyte MVs (9797 (4763-53444)), monocyte MVs (438 (196-25,627)), alveolar macrophage MVs (755 (343-6054) and platelets MVs (564 (286-953)) (MVs/µL, median (IQR)). Patients with PaO2/FiO2 (P/F) ratio ≤ 200mmHg at 72 hours had significantly higher levels of BALF neutrophil MVs than those with P/F ratio > 200mmHg (p=0.001). Patients who developed PGD also had significantly higher BALF neutrophil MVs than those who did not (p=0.03). Conclusions: We have undertaken a comprehensive evaluation of MVs within BALF of lung transplant recipients and demonstrated an association of BALF neutrophil MV numbers and PGD. Our data may suggest BALF neutrophil MVs as a potential, clinically relevant biomarker for PGD. Moreover, these MV may also have a pathogenic/inflammatory role in development of PGD

Microvesicles (MVs), a plasma membrane-derived subclass of extracellular vesicles, are produced and released into the circulation during systemic inflammation, yet little is known of cell/tissue-specific uptake of MVs under these conditions. We hypothesized that monocytes contribute to uptake of circulating MVs and that their increased margination to the pulmonary circulation and functional priming during systemic inflammation produces substantive changes to the systemic MV homing profile. Cellular uptake of i.v.-injected, fluorescently labelled MVs (J774.1 macrophage-derived) in vivo was quantified by flow cytometry in vascular cell populations of the lungs, liver and spleen of C57BL6 mice. Under normal conditions, both Ly6Chigh and Ly6Clow monocytes contributed to MV uptake but liver Kupffer cells were the dominant target cell population. Following induction of sub-clinical endotoxemia with low-dose i.v. LPS, MV uptake by lung-marginated Ly6Chigh monocytes increased markedly, both at the individual cell level (~2.5-fold) and through substantive expansion of their numbers (~8-fold), whereas uptake by splenic macrophages was unchanged and uptake by Kupffer cells actually decreased (~50%). Further analysis of MV uptake within the pulmonary vasculature using a combined model approach of in vivo macrophage depletion, ex vivo isolated perfused lungs and in vitro lung perfusate cell-based assays, indicated that Ly6Chigh monocytes possess a high MV uptake capacity (equivalent to Kupffer cells), that is enhanced directly by endotoxemia and ablated in the presence of phosphatidylserine (PS)-enriched liposomes and β3 integrin receptor blocking peptide. Accordingly, i.v.-injected PS-enriched liposomes underwent a redistribution of cellular uptake during endotoxemia similar to MVs, with enhanced uptake by Ly6Chigh monocytes and reduced uptake by Kupffer cells. These findings indicate that monocytes, particularly lung-marginated Ly6Chigh subset monocytes, become a dominant target cell population for MVs during systemic inflammation, with significant implications for the function and targeting of endogenous and therapeutically administered MVs, lending novel insights into the pathophysiology of pulmonary vascular inflammation.

Despite advances in the pathophysiology of Chronic Obstructive Pulmonary Disease (COPD), there is a distinct lack of biochemical markers to aid clinical management. Microvesicles (MVs) have been implicated in the pathophysiology of inflammatory diseases including COPD but their association to COPD disease severity remains unknown. We analysed different MV populations in plasma and bronchoalveolar lavage fluid (BALF) taken from sixty-two patients with mild to very severe COPD (51% male; mean age: 65.9 years). These patients underwent comprehensive clinical evaluation (symptom scores, lung function, exercise testing) and the capacity of MVs to be clinical markers of disease severity was assessed. We successfully identified various MV subtype populations within BALF (leukocyte, PMN (polymorphonuclear leukocyte i.e. neutrophil), monocyte, epithelial and platelet MVs) and plasma (leukocyte, PMN, monocyte and endothelial MVs), and compared each MV population to disease severity. BALF neutrophil MVs were the only population to significantly correlate with the clinical evaluation scores including FEV1, mMRC dyspnoea score, 6-minute walk test, hyperinflation and gas transfer. BALF neutrophil MVs, but not neutrophil cell numbers, also strongly correlated with BODE index. We have undertaken, for the first time, a comprehensive evaluation of MV profiles within BALF/plasma of COPD patients. We demonstrate that BALF levels of neutrophil-derived MVs are unique in correlating with a number of key functional and clinically-relevant disease severity indices. Our results show the exciting potential of BALF neutrophil MVs for a COPD biomarker that tightly links, for the first time, a key pathophysiological mechanism of COPD (intra-alveolar neutrophil activation) with clinical severity/outcome.

Introduction: Acute respiratory distress syndrome (ARDS) is a heterogeneous and multifactorial disease; it is a common and devastating condition that has a high mortality. Treatment is limited to supportive measures hence novel pharmacological approaches are necessary. We propose a new direction in ARDS research; this means moving away from thinking about individual inflammatory mediators and instead investigating how packaged information is transmitted between cells. Microvesicles (MVs) represent a novel vehicle for inter-cellular communication with an emerging role in ARDS pathophysiology.Areas covered: This review examines current approaches to ARDS and emerging MV research. We describe advances in our understanding of microvesicles and focus on their pro-inflammatory roles in airway and endothelial signaling. We also offer reasons for why MVs are attractive therapeutic targets.Expert opinion: MVs have a key role in ARDS pathophysiology. Preclinical studies must move away from simple models toward more realistic scenarios while clinical studies must embrace patient heterogeneity. Microvesicles have the potential to aid identification of patients who may benefit from particular treatments and act as biomarkers of cellular status and disease progression. Understanding microvesicle cargoes and their cellular interactions will undoubtedly uncover new targets for ARDS.

BackgroundDespite advances in understanding the pathophysiology of acute respiratory distress syndrome, effective pharmacological interventions have proven elusive. We believe this is a consequence of existing preclinical models being designed primarily to explore biological pathways, rather than predict treatment effects. Here, we describe a mouse model in which both therapeutic intervention and ventilation were superimposed onto existing injury and explored the impact of β-agonist treatment, which is effective in simple models but not clinically.MethodsMice had lung injury induced by intranasal lipopolysaccharide (LPS), which peaked at 48 hours post-LPS based on clinically relevant parameters including hypoxaemia and impaired mechanics. At this peak of injury, mice were treated intratracheally with either terbutaline or tumour necrosis factor (TNF) receptor 1-targeting domain antibody, and ventilated with moderate tidal volume (20 mL/kg) to induce secondary ventilator-induced lung injury (VILI).ResultsVentilation of LPS-injured mice at 20 mL/kg exacerbated injury compared with low tidal volume (8 mL/kg). While terbutaline attenuated VILI within non-LPS-treated animals, it was ineffective to reduce VILI in pre-injured mice, mimicking its lack of clinical efficacy. In contrast, anti-TNF receptor 1 antibody attenuated secondary VILI within pre-injured lungs, indicating that the model was treatable.ConclusionsWe propose adoption of a practical framework like that described here to reduce the number of ultimately ineffective drugs reaching clinical trials. Novel targets should be evaluated alongside interventions which have been previously tested clinically, using models that recapitulate the (lack of) clinical efficacy. Within such a framework, outperforming a failed pharmacologic should be a prerequisite for drugs entering trials.

Cellular stress or injury induces release of endogenous danger signals such as ATP, which plays a central role in activating immune cells. ATP is essential for the release of nonclassically secreted cytokines such as IL-1β but, paradoxically, has been reported to inhibit the release of classically secreted cytokines such as TNF. Here, we reveal that ATP does switch off soluble TNF (17 kDa) release from LPS-treated macrophages, but rather than inhibiting the entire TNF secretion, ATP packages membrane TNF (26 kDa) within microvesicles (MVs). Secretion of membrane TNF within MVs bypasses the conventional endoplasmic reticulum– and Golgi transport–dependent pathway and is mediated by acid sphingomyelinase. These membrane TNF–carrying MVs are biologically more potent than soluble TNF in vivo, producing significant lung inflammation in mice. Thus, ATP critically alters TNF trafficking and secretion from macrophages, inducing novel unconventional membrane TNF signaling via MVs without direct cell-to-cell contact. These data have crucial implications for this key cytokine, particularly when therapeutically targeting TNF in acute inflammatory diseases.—Soni, S., O’Dea, K. P., Tan, Y. Y., Cho, K., Abe, E., Romano, R., Cui, J., Ma, D., Sarathchandra, P., Wilson, M. R., Takata, M. ATP redirects cytokine trafficking and promotes novel membrane TNF signaling via microvesicles.

Background: Microvesicles (MV) play an important role in mediating intra-alveolar inflammation during acute lung injury (Soni et al. Thorax 2016). We investigated the profile of MVs present within bronchoalveolar lavage fluid (BALF) and plasma in patients with another inflammatory disease, COPD, and assessed relationship to disease severity. Methods: Moderate to severe COPD patients (n=30) underwent clinical evaluation (symptom scores, lung function, exercise testing) and bronchoscopy. Paired plasma/BALF samples were analysed by flow cytometry for MVs derived from leucocytes (CD45+), neutrophils (CD66b+/CD11b+), monocytes (CD45+/CD14+), alveolar macrophages (CD206+/CD71+), platelets (CD31+/42b+), epithelial (EpCAM+/T1α+) and endothelial cells (CD146+/CD62E+/CD144+). Results: We identified MV subpopulations within BALF (leukocyte, neutrophil, monocyte, alveolar macrophage, epithelial, platelet) and plasma (leukocyte, neutrophil, monocyte, endothelial) samples. Only BALF neutrophil MV numbers correlated with modified MRC dyspnoea scale (p Conclusions: We have undertaken for the first time a comprehensive evaluation of MVs within BALF/plasma of COPD patients, and demonstrated BALF neutrophil-derived MV numbers correlate with functional and clinically relevant disease severity indices. Our data strongly suggest BALF neutrophil MVs are a novel, clinically relevant biomarker for COPD disease severity, and may have a pathogenic role in COPD progression and be a potential target to modulate the inflammation in COPD.

Background: ATP triggers cells to release microvesicles (MVs), which play crucial roles in cellular communication by ferrying molecular cargo between cells. MVs may protect its contents from dilution, degradation or consumption, yet there is a paucity of literature examining TNF release within intra-alveolar MVs. Aims/Objectives: To investigate if ATP causes alveolar macrophages (AM) to preferentially release TNF within MVs. Methods: Primary mouse AMs were activated with 1µg/ml LPS, and then exposed to a 9second hit9 of ATP 6mM/ecto-ATPase inhibitor 1mM for 1 hour to produce MVs (identified on flow cytometry as CD11c+, Results: ATP treatment eradicated soluble TNF release from AMs (Control 107±13 pg vs ATP 4.8±6.1 pg, p Conclusion: These data show that a danger signal such as ATP, superimposed onto a pro-inflammatory stimulus, suppresses TNF release from AMs in the ordinary soluble form but preferentially packages TNF within MVs. This switch phenomenon indicates a novel mechanism of long-range TNF signalling in inflammatory lung diseases such as acute lung injury.

Microvesicles (MVs) are important mediators of intercellular communication, packaging a variety of molecular cargo. They have been implicated in the pathophysiology of various inflammatory diseases; yet, their role in acute lung injury (ALI) remains unknown.We aimed to identify the biological activity and functional role of intra-alveolar MVs in ALI.Lipopolysaccharide (LPS) was instilled intratracheally into C57BL/6 mice, and MV populations in bronchoalveolar lavage fluid (BALF) were evaluated. BALF MVs were isolated 1 hour post LPS, assessed for cytokine content and incubated with murine lung epithelial (MLE-12) cells. In separate experiments, primary alveolar macrophage-derived MVs were incubated with MLE-12 cells or instilled intratracheally into mice.Alveolar macrophages and epithelial cells rapidly released MVs into the alveoli following LPS. At 1 hour, the dominant population was alveolar macrophage-derived, and these MVs carried substantive amounts of tumour necrosis factor (TNF) but minimal amounts of IL-1β/IL-6. Incubation of these mixed MVs with MLE-12 cells induced epithelial intercellular adhesion molecule-1 (ICAM-1) expression and keratinocyte-derived cytokine release compared with MVs from untreated mice (p0.001). MVs released in vitro from LPS-primed alveolar macrophages caused similar increases in MLE-12 ICAM-1 expression, which was mediated by TNF. When instilled intratracheally into mice, these MVs induced increases in BALF neutrophils, protein and epithelial cell ICAM-1 expression (p0.05).We demonstrate, for the first time, the sequential production of MVs from different intra-alveolar precursor cells during the early phase of ALI. Our findings suggest that alveolar macrophage-derived MVs, which carry biologically active TNF, may play an important role in initiating ALI.

Background: Microvesicles (MVs), extracellular particles Aims/Objectives: We hypothesised that alveolar macrophages (AMs) release MVs which contain TNF and can activate other intra-alveolar cells during ALI. Methods: AMs, harvested from C57BL/6 mice, were treated with lipopolysaccharide and then stimulated to produce MVs with ATP/calcium ionophore. Cell-free supernatant underwent high-speed centrifugation to produce a MV pellet and MV-free supernatant. MVs were identified ( + , detergent sensitive) and examined for TNF expression by flow cytometry/ELISA. MVs were incubated with murine lung epithelial (MLE) cells and ICAM-1 was measured on MLE by flow cytometry (n=5-6 for all protocols). Results: AMs released CD11c + MVs (4250±814/µL mean±SD) and >87% were TNF positive. TNF content of MVs was confirmed by ELISA following sonication of samples (14±12 pg/ml in MV pellet vs. 0 pg/ml in MV-free supernatant). Co-culture of MLE cells with MVs led to an increase in MLE ICAM-1 expression compared to culture with MV-free supernatant (12.4±2.6 MFI vs. 7.8±1.8 MFI, p Conclusions: We demonstrate, for the first time, that AMs, an active source of pro-inflammatory cytokines during ALI, can release TNF-laden MVs, which activate MLE cells. These results suggest that MV-mediated inflammatory activation within the alveolar space may play a previously unappreciated, important role in the pathophysiology of ALI.

Intussusception is an uncommon cause of abdominal pain in adults and poses diagnostic challenges for emergency physicians, due to its varied presenting symptoms and time course. Diagnosis is thus often delayed and results in surgical intervention due to the development of bowel ischaemia. We report on a young patient who presented with an ileo-ileal intussusception in whom there were no underlying lesions identified as a causal factor.