Endotracheal Tube Obstruction Among Patients Mechanically Ventilated for ARDS Due to COVID-19: A Case Series

Impact of Humidification Modality on Incidence of Endotracheal Tube Occlusion in COVID-19 Patients

Background: Endotracheal tube (ETT) occlusion is reported at a higher frequency among coronavirus disease-2019 (COVID-19) patients. Prior to the COVID-19 pandemic, literature examining patient and ventilator characteristics, including humidification, as etiologies of ETT occlusion yielded mixed results. Our study examines the relationship of humidification modality with ETT occlusion in COVID-19 patients undergoing invasive mechanical ventilation (IMV). Methods: We conducted a retrospective chart review of COVID-19 patients requiring IMV at a tertiary care center in New York from April 2020 to April 2021. Teleflex Neptune heated wire heated humidification (HH) and hygroscopic Intersurgical FiltaTherm and Sunmed Ballard 1500 heat and moisture exchangers (HME) were used. Episodes of ETT occlusion were recorded. Univariate and multivariable logistic regression models were used to investigate the relationship between humidification modality and the occurrence of ETT occlusion. Findings: A total of 201 eligible patients were identified. Teleflex HH was utilized in 50.2% of the population and the others Intersurgical and Sunmed HME devices. Median age was 62 years and 78.6% of patients had at least one medical comorbidity. Precisely, 24% of patients experienced an ETT occlusion after a median of 12 days. The HME group was younger (58.5 vs 64 years), predominantly male (75% vs 59.4%), and experienced more total ventilator days than the HH group (24 vs 12). Those using the studied HME devices had significantly higher odds of ETT occlusion (OR 4.4, 95% CI 1.8-10.6, P = .0011). Three patients (6.1%) experienced cardiac arrest as a consequence of their occlusion. There were no deaths directly attributed to ETT occlusion. Conclusions: The studied HME devices were significantly associated with higher odds of ETT occlusion in COVID-19 patients requiring invasive mechanical ventilation. These events are not without significant clinical consequences. Prolonged use of under-performing HME devices remains suspect in the occurrence of ETT occlusions.

Effect of the duration of prone position in ARDS patients during the SARS-CoV-2 pandemic

OBJECTIVE

To describe the characteristics of patients with acute respiratory distress syndrome (ARDS) due to bilateral COVID-19 pneumonia on invasive mechanical ventilation (IMV), and to analyze the effect of prone position >24 h (prolonged) (PPP) compared to prone decubitus <24 h (PP).

DESIGN

A retrospective observational descriptive study was carried out, with uni- and bivariate analyses.

SETTING

Department of Intensive Care Medicine. Hospital General Universitario de Elche (Elche, Alicante, Spain).

PARTICIPANTS

Patients with SARS-CoV-2 pneumonia (2020-2021) on IMV due to moderate-severe ARDS, ventilated in prone position (PP).

INTERVENTIONS

IMV. PP maneuvers.

MAIN VARIABLES OF INTEREST

Sociodemographic characteristics, analgo-sedation, neuromuscular blockade (NMB), PD duration, ICU stay and mortality, days of IMV, non-infectious complications, healthcare associated infections.

RESULTS

Fifty-one patients required PP, and of these, 31 (69.78%) required PPP. No differences were observed in terms of patient characteristics (gender, age, comorbidities, initial severity, antiviral and antiinflammatory treatment received). Patients on PPP had poorer tolerance to supine ventilation (61.29% vs 89.47%, p = 0.031), longer hospital stay (41 vs 30 days, p = 0.023), more days of IMV (32 vs 20 days, p = 0.032), longer duration of NMB (10.5 vs 3 days, p = 0.0002), as well as a higher percentage of episodes of orotracheal tube obstruction (48.39% vs 15%, p = 0.014).

CONCLUSIONS

PPP was associated with greater resource use and complications in patients with moderate-severe ARDS due to COVID-19.

Chronic airway epithelial hypoxia exacerbates injury in muco-obstructive lung disease through mucus hyperconcentration

Unlike solid organs, human airway epithelia derive their oxygen from inspired air rather than the vasculature. Many pulmonary diseases are associated with intraluminal airway obstruction caused by aspirated foreign bodies, virus infection, tumors, or mucus plugs intrinsic to airway disease, including cystic fibrosis (CF). Consistent with requirements for luminal O2, airway epithelia surrounding mucus plugs in chronic obstructive pulmonary disease (COPD) lungs are hypoxic. Despite these observations, the effects of chronic hypoxia (CH) on airway epithelial host defense functions relevant to pulmonary disease have not been investigated. Molecular characterization of resected human lungs from individuals with a spectrum of muco-obstructive lung diseases (MOLDs) or COVID-19 identified molecular features of chronic hypoxia, including increased EGLN3 expression, in epithelia lining mucus-obstructed airways. In vitro experiments using cultured chronically hypoxic airway epithelia revealed conversion to a glycolytic metabolic state with maintenance of cellular architecture. Chronically hypoxic airway epithelia unexpectedly exhibited increased MUC5B mucin production and increased transepithelial Na+ and fluid absorption mediated by HIF1α/HIF2α-dependent up-regulation of β and γENaC (epithelial Na+ channel) subunit expression. The combination of increased Na+ absorption and MUC5B production generated hyperconcentrated mucus predicted to perpetuate obstruction. Single-cell and bulk RNA sequencing analyses of chronically hypoxic cultured airway epithelia revealed transcriptional changes involved in airway wall remodeling, destruction, and angiogenesis. These results were confirmed by RNA-in situ hybridization studies of lungs from individuals with MOLD. Our data suggest that chronic airway epithelial hypoxia may be central to the pathogenesis of persistent mucus accumulation in MOLDs and associated airway wall damage.

Prevalence and Mechanisms of Mucus Accumulation in COVID-19 Lung Disease

Rationale: The incidence and sites of mucus accumulation and molecular regulation of mucin gene expression in coronavirus (COVID-19) lung disease have not been reported. Objectives: To characterize the incidence of mucus accumulation and the mechanisms mediating mucin hypersecretion in COVID-19 lung disease. Methods: Airway mucus and mucins were evaluated in COVID-19 autopsy lungs by Alcian blue and periodic acid-Schiff staining, immunohistochemical staining, RNA in situ hybridization, and spatial transcriptional profiling. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected human bronchial epithelial (HBE) cultures were used to investigate mechanisms of SARS-CoV-2-induced mucin expression and synthesis and test candidate countermeasures. Measurements and Main Results: MUC5B and variably MUC5AC RNA concentrations were increased throughout all airway regions of COVID-19 autopsy lungs, notably in the subacute/chronic disease phase after SARS-CoV-2 clearance. In the distal lung, MUC5B-dominated mucus plugging was observed in 90% of subjects with COVID-19 in both morphologically identified bronchioles and microcysts, and MUC5B accumulated in damaged alveolar spaces. SARS-CoV-2-infected HBE cultures exhibited peak titers 3 days after inoculation, whereas induction of MUC5B/MUC5AC peaked 7-14 days after inoculation. SARS-CoV-2 infection of HBE cultures induced expression of epidermal growth factor receptor (EGFR) ligands and inflammatory cytokines (e.g., IL-1α/β) associated with mucin gene regulation. Inhibiting EGFR/IL-1R pathways or administration of dexamethasone reduced SARS-CoV-2-induced mucin expression. Conclusions: SARS-CoV-2 infection is associated with a high prevalence of distal airspace mucus accumulation and increased MUC5B expression in COVID-19 autopsy lungs. HBE culture studies identified roles for EGFR and IL-1R signaling in mucin gene regulation after SARS-CoV-2 infection. These data suggest that time-sensitive mucolytic agents, specific pathway inhibitors, or corticosteroid administration may be therapeutic for COVID-19 lung disease.

Congestion in the tube: air trapping in a ventilated patient with COVID-19 secondary to mucinous valves

A woman in her 50s was admitted to the intensive therapy unit with acute hypoxaemic respiratory failure secondary to COVID-19 pneumonitis. The patient was intubated on admission and worsening gas exchange necessitated multiple rounds of proning . She later improved, and her ventilation was switched to spontaneous mode. However, the patient started to develop air trapping with subsequent respiratory and cardiovascular compromise. Routine investigations showed no clear cause for her sudden deterioration and a suction catheter passed easily through the endotracheal tube. Bronchoscopy revealed mucinous/phlegmatic membranes had developed across the inner diameter of the endotracheal tube. This had created a one-way valve that allowed positive pressure ventilation through the tube into her lungs but only allowed a fraction of air to passively escape in expiration. This case report highlights a less commonly regarded complication associated with long-term intubation and lack of circuit humidification in the context of productive lung pathology.

Ex-vivo mucolytic and anti-inflammatory activity of BromAc in tracheal aspirates from COVID-19

COVID-19 is a lethal disease caused by the pandemic SARS-CoV-2, which continues to be a public health threat. COVID-19 is principally a respiratory disease and is often associated with sputum retention and cytokine storm, for which there are limited therapeutic options. In this regard, we evaluated the use of BromAc®, a combination of Bromelain and Acetylcysteine (NAC). Both drugs present mucolytic effect and have been studied to treat COVID-19. Therefore, we sought to examine the mucolytic and anti-inflammatory effect of BromAc® in tracheal aspirate samples from critically ill COVID-19 patients requiring mechanical ventilation.

Method

Tracheal aspirate samples from COVID-19 patients were collected following next of kin consent and mucolysis, rheometry and cytokine analysis using Luminex kit was performed.

Results

BromAc® displayed a robust mucolytic effect in a dose dependent manner on COVID-19 sputum ex vivo. BromAc® showed anti-inflammatory activity, reducing the action of cytokine storm, chemokines including MIP-1alpha, CXCL8, MIP-1b, MCP-1 and IP-10, and regulatory cytokines IL-5, IL-10, IL-13 IL-1Ra and total reduction for IL-9 compared to NAC alone and control. BromAc® acted on IL-6, demonstrating a reduction in G-CSF and VEGF-D at concentrations of 125 and 250 µg.

Conclusion

These results indicate robust mucolytic and anti-inflammatory effect of BromAc® ex vivo in tracheal aspirates from critically ill COVID-19 patients, indicating its potential to be further assessed as pharmacological treatment for COVID-19.

Recycling plastic: diagnosis and management of plastic bronchitis among adults

Plastic bronchitis is a rare, underdiagnosed and potentially fatal condition. It is characterised by the formation and expectoration of branching gelatinous plugs that assume the shape of the airways. These airway plugs differ from the allergic mucin that characterises allergic bronchopulmonary aspergillosis and mucoid impaction of the bronchi. Plastic bronchitis is most often encountered in the paediatric population following corrective cardiac surgery, such as the Fontan procedure. It also occurs in adults. Plastic bronchitis in adults is rare, heterogeneous in its aetiology, and can lead to respiratory distress or even life-threatening airway obstruction. Plastic bronchitis in adulthood should not be overlooked, particularly in patients with chronic inflammatory lung diseases. This review presents current understanding of the presentation, aetiology, pathogenesis, pathology and management of plastic bronchitis in adults.