Nebulized heparin and salbutamol versus salbutamol alone in acute exacerbations of chronic obstructive pulmonary disease requiring mechanical ventilation: a double-blind randomized controlled trial

Prognostic Significance of Thrombocytopenia and Mean Platelet Volume in COPD Patients with Acute Exacerbations in ICU Settings

BACKGROUND Platelets have important modulatory effects on inflammatory and immune-mediated pathways. Thrombocytopenia is a critical condition that is frequently encountered in the intensive care unit (ICU) and increases mortality. This retrospective study of 472 patients admitted to the ICU with acute exacerbation of chronic obstructive pulmonary disease (COPD) aimed to evaluate thrombocytopenia and mean platelet volume (MPV) with prognosis and patient mortality. MATERIAL AND METHODS A total of 472 patients diagnosed with COPD according to GOLD criteria and hospitalized in the tertiary ICU between 1 April 2018 and 11 May 2021 were included in the study. Platelets were calculated by the impetance method and MPV was simultaneously calculated based on the platelet histogram. Patients with platelet count ≤100×10⁹/L and >100×10⁹/L and patients with MPV values <7 fl, 7-11 fl, and >11fl were compared in terms of mortality and prognosis. RESULTS The mortality rate in COPD patients with thrombocytopenia was high, at 61.5%. Thrombocytopenia (P=.002), high MPV (P=.006) Acute Physiology and Chronic Health Evaluation-2 (APACHE-II) score (P=.025), length of stay (LOS) in the ICU (P=.009), mechanical ventilation duration (P<.001), leukocytosis (P<.001), high Sequential Organ Failure Assessment (SOFA) score (P<.001), LOS in the hospital (P=.035), and hypoalbuminemia (P<.001) were significantly associated with mortality. CONCLUSIONS Thrombocytopenia, high MPV, high APACHE-II and SOFA scores, LOS in the ICU and hospital, duration of mechanical ventilation, leukocytosis, and hypoalbuminemia predict mortality in COPD patients. Since infection-sepsis, hypoalbuminemia, and hypoxia can worsen this situation, ensuring early infection control, providing albumin support, and preventing hypoxia contribute significantly to reducing thrombocytopenia and mortality.

The effect of nebulized heparin on clinical outcomes in mechanically ventilated patients: a meta-analysis and review of the literature

OBJECTIVE

To determine the relationship between use of nebulized heparin and clinical outcomes in mechanically ventilated patients.

METHODS

The Medline, Embase, Web of Science, Cochrane Library, and PubMed databases were searched for relevant randomized controlled trials (RCTs), published between database inception and May 2022. Primary outcomes were intensive care unit (ICU) length of stay and in-hospital mortality; secondary outcomes included duration of mechanical ventilation, ventilator-free days (VFDs) in 28 days, and length of hospitalization. The study protocol was registered on PROSPERO (registration No: CRD42022345533).

RESULTS

A total of eight RCTs (651 patients) were included. Nebulized heparin was associated with reduced ICU length of stay (six studies; mean difference [MD] -1.10, 95% confidence interval [CI] -1.87, -0.33, I2 = 76%), reduced duration of mechanical ventilation (two studies; MD -2.63, 95% CI -3.68, -1.58, I2 = 92%) and increased VFDs in 28 days (two studies; MD 4.22, 95% CI 1.10, 7.35, I2 = 18%), without increased incidence of adverse events, such as bleeding; but was not associated with a reduction in length of hospitalization (three studies; MD -1.00, 95% CI -2.90, -0.90, I2 = 0%) or in-hospital mortality (five studies; odds ratio 1.10, 95% CI 0.69, 1.77, I2 = 0%).

CONCLUSION

Nebulized heparin reduces ICU length of stay and duration of mechanical ventilation in mechanically ventilated patients, but has no effect on length of hospitalization or mortality.

Efficacy and safety of inhaled heparin in asthmatic and chronic obstructive pulmonary disease patients: a systematic review and a meta-analysis

Asthma and chronic obstructive pulmonary disease (COPD) are prevalent chronic respiratory disorders that cause significant morbidity and mortality. Some studies evaluated the use of inhaled unfractionated heparin (UFH) in the treatment of asthma and COPD. We aimed to synthesize the available evidence for the efficacy and safety of inhaled heparin in improving lung functions among asthmatic and COPD patients. A comprehensive search was performed using Pubmed, Embase, EBSCO, Scopus, Web of Science, Cochrane CENTRAL, WHO Clinical trials, clinicaltrials.gov, Iranian Clinical trials, Google Scholar, Research Gate, ProQuest Thesis, OVID, and medRxiv databases. Two independent reviewers included all pertinent articles according to PRISMA guidelines, and extract data independently. The two reviewers checked the quality of studies using the ROB2 tool. To determine the pooled effect estimate of the efficacy and safety of inhaled heparin, a meta-analysis was carried out using the R programming language. Publication bias was evaluated using Egger's regression test. The heterogeneity was explained using a meta-regression, and the quality of evidence was assessed by the GRADE approach. Twenty-six studies with a total of 581 patients were included in the qualitative analysis and 16 in the meta-analysis. The primary outcome was treatment success (improvement of lung function) that was measured by standardized mean differences (SMD) of the forced expiratory volume per second (FEV1) either per ml or percentage. Heparin has a large effect on both FEV1% and FEV1 ml when compared to the control group (SMD 2.7, 95% CI 1.00; 4.39; GRADE high, SMD 2.12, 95% CI - 1.49; 5.72: GRADE moderate, respectively). Secondary outcomes are other lung functions improving parameters such as PC20 (SMD 0.91, 95% CI - 0.15; 1.96). Meta-regression and subgroup analysis show that heparin type, dose, year of publication, study design, and quality of studies had a substantial effect. Regarding safety, inhaled heparin showed a good coagulation profile and mild tolerable side effects. Inhaled heparin showed improvement in lung functions either alone or when added to standard care. More large parallel RCTs are needed including COPD patients, children, and other types, and stages of asthmatic patients.

Heparin, Low Molecular Weight Heparin, and Non-Anticoagulant Derivatives for the Treatment of Inflammatory Lung Disease

Unfractionated heparin has multiple pharmacological activities beyond anticoagulation. These anti-inflammatory, anti-microbial, and mucoactive activities are shared in part by low molecular weight and non-anticoagulant heparin derivatives. Anti-inflammatory activities include inhibition of chemokine activity and cytokine synthesis, inhibitory effects on the mechanisms of adhesion and diapedesis involved in neutrophil recruitment, inhibition of heparanase activity, inhibition of the proteases of the coagulation and complement cascades, inhibition of neutrophil elastase activity, neutralisation of toxic basic histones, and inhibition of HMGB1 activity. This review considers the potential for heparin and its derivatives to treat inflammatory lung disease, including COVID-19, ALI, ARDS, cystic fibrosis, asthma, and COPD via the inhaled route.

Pharmacology of Heparin and Related Drugs: An Update

Heparin has been used extensively as an antithrombotic and anticoagulant for close to 100 years. This anticoagulant activity is attributed mainly to the pentasaccharide sequence, which potentiates the inhibitory action of antithrombin, a major inhibitor of the coagulation cascade. More recently it has been elucidated that heparin exhibits anti-inflammatory effect via interference of the formation of neutrophil extracellular traps and this may also contribute to heparin's antithrombotic activity. This illustrates that heparin interacts with a broad range of biomolecules, exerting both anticoagulant and nonanticoagulant actions. Since our previous review, there has been an increased interest in these nonanticoagulant effects of heparin, with the beneficial role in patients infected with SARS2-coronavirus a highly topical example. This article provides an update on our previous review with more recent developments and observations made for these novel uses of heparin and an overview of the development status of heparin-based drugs. SIGNIFICANCE STATEMENT: This state-of-the-art review covers recent developments in the use of heparin and heparin-like materials as anticoagulant, now including immunothrombosis observations, and as nonanticoagulant including a role in the treatment of SARS-coronavirus and inflammatory conditions.

Efficacy of High-Dose Vitamin C Infusion on Outcomes in Sepsis Requiring Mechanical Ventilation: A Double-Blind Randomized Controlled Trial

Background. Critically ill patients have an increased requirement for vitamin C in sepsis and these patients have low levels of vitamin C. The researchers validated the efficacy of high-dose vitamin C intravenous infusion (IVI) in patients with sepsis requiring mechanical ventilation. Methods. Forty patients were randomly assigned to 2 groups (20 each) in a 1 : 1 ratio in accordance with the vitamin C treatment regimen: Group I (GI): patients received 1.5 g/6 h vitamin C in 50 ml of dextrose 5% in water (D5W) IVI over 30 minutes for 4 consecutive days; Group II (GII): patients received 100 mg vitamin C/day as a first single dose in 50 ml of D5W IVI over 30 minutes and the other three subsequent doses were 50 ml of plain D5W IVI over 30 minutes for 4 consecutive days. Primary outcomes were the change in sequential organ failure assessment (SOFA) score at day 7, the incidence of ventilator-associated pneumonia (VAP), and the plasma vitamin C level. The glutathione peroxidase (GPX) activity, C-reactive protein (CRP) level, duration of vasopressor therapy, and 28-day mortality were secondary outcomes. Results. The change in SOFA score at day 7 showed a significant difference between GI and GII ( $p<0.001$ ). The incidence of early VAP was significantly lower in GI ( $p=0.044$ ). Vitamin C levels showed a significant rise in GI at day 1 and day 4 ( $p<0.001$ and $p<0.001$ , respectively). GPX activity of day 4 and day 7 was significantly higher in GI ( $p=0.005$ and $p=0.014$ , respectively). CRP levels of day 4 and day 7 were significantly higher in GII ( $p<0.001$ and $p<0.001$ , respectively). There was a significant difference in 28-day mortality ( $p=0.038$ ) and duration of vasopressor therapy ( $p=0.033$ ) in GI compared to GII. Conclusion. The early use of high-dose vitamin C intravenous infusion in patients with sepsis requiring mechanical ventilation in combination with the standard treatment for sepsis lowered the incidence of VAP, increased the antioxidant status, and improved the illness severity. Trial Registration. This trial is registered with ClinicalTrials.gov Identifier (NCT04029675).

Anticoagulation as a therapeutic strategy for hospitalised patients with COVID-19

The COVID-19 pandemic has devastated the global community and continues to cause significant morbidity and mortality worldwide. The development of effective vaccines has represented a major step towards reducing transmission and illness severity but significant challenges remain, particularly in regions where vaccine access has been limited. COVID-19 is associated with hypercoagulability and increased risk of thrombosis, with greatest risk among the critically ill. Interestingly, early observational data suggested that anticoagulant therapy might improve clinical outcomes, aside from thrombotic events, in patients with COVID-19. In this review we summarise data generated from three published randomised clinical trials which have sought to determine the effect of therapeutic heparin anticoagulation on efficacy and safety outcomes in hospitalised patients with COVID-19: the multiplatform REMAP-CAP, ACTIV-4a and ATTACC randomised controlled trials and the RAPID trial. In the multiplatform REMAP-CAP, ACTIV-4a and ATTACC randomised controlled trials, therapeutic heparin was not associated with benefit in critically ill patients with COVID-19 compared with usual care (adjusted proportional odds ratio (OR) for increased organ-support free days up to day 21: 0.83; 95% credible interval, 0.67-1.03, posterior probability of futility 99.9%). Conversely, among hospitalised patients without critical illness, therapeutic heparin was associated with an increased probability of organ support-free days alive (adjusted OR, 1.27; 95% credible interval, 1.03-1.58). The RAPID trial also evaluated the effect of therapeutic heparin compared with prophylactic heparin in non-critically ill patients. In this study, therapeutic heparin did not significantly reduce the odds of the primary composite outcome (death, mechanical ventilation or intensive care unit admission) (OR 0.69; 95% confidence interval [CI], 0.43 to 1.10; p = 0.12) but was associated with a significant reduction in all-cause mortality [OR, 0.22 (95%-CI, 0.07 to 0.65)]. Collectively these studies suggest that therapeutic anticoagulation with heparin may reduce the severity of illness and potentially even confer a survival benefit in hospitalised, non-critically ill patients with COVID-19. No benefit for therapeutic anticoagulation with heparin was evident in critically ill patients with COVID-19. Therefore, while the results of additional studies in this evolving field are pending, it is important to approach decisions regarding therapeutic heparin in moderately ill hospitalised patients with COVID-19 in a measured and individualised manner.

Transparency considerations for describing statistical analyses in research

Researchers who use the results of statistical analyses to draw conclusions about collected data must write a statistical analysis section in their manuscript. Describing statistical analyses in precise detail is as important as presenting the dosages of drugs and methodology of interventions. It is also essential for scientific accuracy and transparency in scientific research. We evaluated the quality of the statistical analysis sections of clinical research articles published in the Korean Journal of Anesthesiology between February 2020 and February 2021. Using a Likert scale where 1, 2, and 3 represented “not described at all,” “partially described,” and “fully described,” respectively, the following 6 items were assessed: 1) stating of the statistical analysis methods used, 2) rationale for and detailed description of the statistical analysis methods used, 3) parameters derived from the statistical analyses, 4) type and version of the statistical software package used, 5) significance level, and 6) sidedness of the test (one-sided vs. two-sided). The first 3 items evaluate issues directly related to the statistical analysis methods used and last 3 are indirectly related items. In all the included articles, the statistical analysis methods used were stated (score of 3). However, only 4 articles (12.9%) fully described the sidedness of the test (score of 3). Authors tend not to describe the sidedness of statistical analysis tests in the methodology section of clinical research articles. It is essential that the sidedness be described in research studies.

Effects of salbutamol on the kinetics of sevoflurane and the occurrence of early postoperative pulmonary complications in patients with mild-to-moderate chronic obstructive pulmonary disease: A randomized controlled study

Bronchodilators dilate the bronchi and increase lung volumes, thereby improving respiratory physiology in patients with chronic obstructive pulmonary disease (COPD). However, their effects on sevoflurane kinetics remain unknown. We aimed to determine whether inhaled salbutamol affected the wash-in and wash-out kinetics of sevoflurane and the occurrence of early postoperative pulmonary complications (PPCs) in patients with COPD undergoing elective surgery. This randomized, placebo-controlled study included 63 consecutive patients with COPD allocated to the salbutamol (n = 30) and control groups (n = 33). The salbutamol group received salbutamol aerosol (2 puffs of ~200 μg) 30 min before anesthesia induction and 30 min before surgery completion. The control group received a placebo. Sevoflurane kinetics were determined by collecting end-tidal samples from the first breaths at 1, 2, 3, 4, 5, 7, 10, and 15 min before the surgery (wash-in) and after closing the vaporizer (wash-out). PPCs were recorded for 7 days. The salbutamol group had higher end-tidal to inhaled sevoflurane ratios (p<0.05, p<0.01) than the control group, from 3 to 10 min during the wash-in period, but no significant differences were observed during the wash-out period. The arterial partial pressure of oxygen to the fraction of inhaled oxygen was significantly higher in the salbutamol group at 30 (320.3±17.6 vs. 291.5±29.6 mmHg; p = 0.033) and 60 min (327.8±32.3 vs. 309.2±30.5 mmHg; p = 0.003). The dead space to tidal volume ratios at 30 (20.5±6.4% vs. 26.3±6.0%, p = 0.042) and 60 min (19.6±5.1% vs. 24.8±5.5%, p = 0.007) and the incidence of bronchospasm (odds ratio [OR] 0.45, 95% confidence interval [CI] 0.23–0.67, p = 0.023) and respiratory infiltration (OR 0.52, 95% CI, 0.40–0.65, p = 0.017) were lower in the salbutamol group. In patients with COPD, salbutamol accelerates the wash-in rate of sevoflurane and decreases the occurrence of postoperative bronchospasm and pulmonary infiltration within the first 7 days.

Coagulation dysfunction in patients with AECOPD and its relation to infection and hypercapnia

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) often have coagulation abnormalities. However, the factors that lead to coagulation dysfunction in acute exacerbation of COPD (AECOPD) remain insufficiently explored. This study aimed to investigate the factors affecting coagulation status in patients with COPD and their influence on thrombosis.

METHODS

Data of COPD patients, including 135 cases in acute exacerbation stage and 44 cases in stable stage from Nov 2016 to Nov 2019 in our hospital, were collected. Healthy people (n = 135) were enrolled as the controls. The coagulation parameters, blood gas indexes and blood routine examination results were collected and analyzed.

RESULTS

White blood count (WBC), neutrophil count, neutrophil percentage (N%), platelet (PLT), prothrombin time (PT), international normalized ratio (INR), fibrinogen (FIB), and activated partial thromboplastin time (APTT) increased, plasma thrombin time (TT) decreased in AECOPD group compared with the control group. In AECOPD group, PT, APTT, and FIB were positively correlated with neutrophils and C-reaction protein levels. PT was positively correlated with PCO2 and negatively with pH. Thrombosis was observed in five acute exacerbation and three stable stage COPD patients.

CONCLUSIONS

Patients with AECOPD presented abnormal coagulation status, which was correlated to infection and hypercapnia and might be potentially the risk factor of thrombosis.

Nebulised heparin for patients with or at risk of acute respiratory distress syndrome: a multicentre, randomised, double-blind, placebo-controlled phase 3 trial

Background

Mechanical ventilation in intensive care for 48 h or longer is associated with the acute respiratory distress syndrome (ARDS), which might be present at the time ventilatory support is instituted or develop afterwards, predominantly during the first 5 days. Survivors of prolonged mechanical ventilation and ARDS are at risk of considerably impaired physical function that can persist for years. An early pathogenic mechanism of lung injury in mechanically ventilated, critically ill patients is inflammation-induced pulmonary fibrin deposition, leading to thrombosis of the microvasculature and hyaline membrane formation in the air sacs. The main aim of this study was to determine if nebulised heparin, which targets fibrin deposition, would limit lung injury and thereby accelerate recovery of physical function in patients with or at risk of ARDS.

Methods

The Can Heparin Administration Reduce Lung Injury (CHARLI) study was an investigator-initiated, multicentre, double-blind, randomised phase 3 trial across nine hospitals in Australia. Adult intensive care patients on invasive ventilation, with impaired oxygenation defined by a PaO₂/FiO₂ ratio of less than 300, and with the expectation of invasive ventilation beyond the next calendar day were recruited. Key exclusion criteria were heparin allergy, pulmonary bleeding, and platelet count less than 50 X 10⁹/L. Patients were randomly assigned 1:1, with stratification by site and using blocks of variable size and random seed, via a web-based system, to either unfractionated heparin sodium 25 000 IU in 5 mL or identical placebo (sodium chloride 0·9% 5 mL), administered using a vibrating mesh membrane nebuliser every 6 h to day 10 while invasively ventilated. Patients, clinicians, and investigators were masked to treatment allocation. The primary outcome was the Short Form 36 Health Survey Physical Function Score (out of 100) of survivors at day 60. Prespecified secondary outcomes, which are exploratory, included development of ARDS to day 5 among at-risk patients, deterioration of the Murray Lung Injury Score (MLIS) to day 5, mortality at day 60, residence of survivors at day 60, and serious adverse events. Analyses followed the intention-to-treat principle. There was no imputation of missing data. The trial is registered with the Australian and New Zealand Clinical Trials Register, number ACTRN12612000418875 .

Findings

Between Sept 4, 2012, and Aug 23, 2018, 256 patients were randomised. Final follow-up was on Feb 25, 2019. We excluded three patients who revoked consent and one ineligible participant who received no intervention. Of 252 patients included in data analysis, the mean age was 58 years (SD 15), 157 (62%) were men, and 118 (47%) had ARDS. 128 (51%) patients were assigned to the heparin group and 124 (49%) to the placebo group, all of whom received their assigned intervention. Survivors in the heparin group (n=97) had similar SF-36 Physical Function Scores at day 60 compared to the placebo group (n=94; mean 53·6 [SD 31·6] vs 48·7 [35·7]; difference 4·9 [95% CI −4·8 to 14·5]; p=0·32). Compared with the placebo group, the heparin group had fewer cases of ARDS develop to day 5 among the at-risk patients (nine [15%] of 62 patients vs 21 [30%] of 71 patients; hazard ratio 0·46 [95% CI 0·22 to 0·98]; p=0·0431), less deterioration of the MLIS to day 5 (difference −0·14 [–0·26 to −0·02]; p=0·0215), similar day 60 mortality (23 [18%] of 127 patients vs 18 [15%] of 123 patients; odds ratio [OR] 1·29 [95% CI 0·66 to 2·53]; p=0·46), and more day 60 survivors at home (86 [87%] of 99 patients vs 73 [73%] of 100 patients; OR 2·45 [1·18 to 5·08]; p=0·0165). A similar number of serious adverse events occurred in each group (seven [5%] of 128 patients in the heparin group vs three [2%] of 124 patients in the placebo group; OR 2·33 [0·59 to 9·24]; p=0·23), which were a transient increase in airway pressure during nebulisation (n=3 in the heparin group), major non-pulmonary bleeding (n=2 in each group), haemoptysis (n=1 in the heparin group), tracheotomy site bleeding (n=1 in the heparin group), and hypoxaemia during nebulisation (n=1 in the placebo group).

Interpretation

In patients with or at risk of ARDS, nebulised heparin did not improve self-reported performance of daily physical activities, but was well tolerated and exploratory outcomes suggest less progression of lung injury and earlier return home. Further research is justified to establish if nebulised heparin accelerates recovery in those who have or are at risk of ARDS.

Funding

Rowe Family Foundation, TR and RB Ditchfield Medical Research Endowment Fund, Patricia Madigan Charitable Trust, and The J and R McGauran Trust Fund.

Animal models of mechanisms of SARS-CoV-2 infection and COVID-19 pathology

The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 infections has led to a substantial unmet need for treatments, many of which will require testing in appropriate animal models of this disease. Vaccine trials are already underway, but there remains an urgent need to find other therapeutic approaches to either target SARS-CoV-2 or the complications arising from viral infection, particularly the dysregulated immune response and systemic complications which have been associated with progression to severe COVID-19. At the time of writing, in vivo studies of SARS-CoV-2 infection have been described using macaques, cats, ferrets, hamsters, and transgenic mice expressing human angiotensin I converting enzyme 2 (ACE2). These infection models have already been useful for studies of transmission and immunity, but to date only partly model the mechanisms involved in human severe COVID-19. There is therefore an urgent need for development of animal models for improved evaluation of efficacy of drugs identified as having potential in the treatment of severe COVID-19. These models need to reproduce the key mechanisms of COVID-19 severe acute respiratory distress syndrome and the immunopathology and systemic sequelae associated with this disease. Here, we review the current models of SARS-CoV-2 infection and COVID-19-related disease mechanisms and suggest ways in which animal models can be adapted to increase their usefulness in research into COVID-19 pathogenesis and for assessing potential treatments. LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.