Single-Site Cannulation Venovenous Extracorporeal CO2 Removal as Bridge to Lung Volume Reduction Surgery in End-Stage Lung Emphysema

The use of extracorporeal CO2 removal in acute respiratory failure

Background

Chronic obstructive pulmonary disease (COPD) exacerbation and protective mechanical ventilation of acute respiratory distress syndrome (ARDS) patients induce hypercapnic respiratory acidosis.

Main text

Extracorporeal carbon dioxide removal (ECCO₂R) aims to eliminate blood CO₂ to fight against the adverse effects of hypercapnia and related acidosis. Hypercapnia has deleterious extrapulmonary consequences, particularly for the brain. In addition, in the lung, hypercapnia leads to: lower pH, pulmonary vasoconstriction, increases in right ventricular afterload, acute cor pulmonale. Moreover, hypercapnic acidosis may further damage the lungs by increasing both nitric oxide production and inflammation and altering alveolar epithelial cells. During an exacerbation of COPD, relieving the native lungs of at least a portion of the CO₂ could potentially reduce the patient's respiratory work, Instead of mechanically increasing alveolar ventilation with MV in an already hyperinflated lung to increase CO₂ removal, the use of ECCO₂R may allow a decrease in respiratory volume and respiratory rate, resulting in improvement of lung mechanic. Thus, the use of ECCO₂R may prevent noninvasive ventilation failure and allow intubated patients to be weaned off mechanical ventilation. In ARDS patients, ECCO₂R may be used to promote an ultraprotective ventilation in allowing to lower tidal volume, plateau (Pplat) and driving pressures, parameters that have identified as a major risk factors for mortality. However, although ECCO₂R appears to be effective in improving gas exchange and possibly in reducing the rate of endotracheal intubation and allowing more protective ventilation, its use may have pulmonary and hemodynamic consequences and may be associated with complications.

Conclusion

In selected patients, ECCO₂R may be a promising adjunctive therapeutic strategy for the management of patients with severe COPD exacerbation and for the establishment of protective or ultraprotective ventilation in patients with ARDS without prognosis-threatening hypoxemia.

Veno-Venous Extracorporeal Lung Support as a Bridge to or Through Lung Volume Reduction Surgery in Patients with Severe Hypercapnia

Extracorporeal lung support (ECLS) represents an essential support tool especially for critically ill patients undergoing thoracic surgical procedures. Lung volume reduction surgery (LVRS) is an important treatment option for end-stage lung emphysema in carefully selected patients. Here, we report the efficacy of veno-venous ECLS (VV ECLS) as a bridge to or through LVRS in patients with end-stage lung emphysema and severe hypercapnia. Between January 2016 and May 2017, 125 patients with end-stage lung emphysema undergoing LVRS were prospectively enrolled into this study. Patients with severe hypercapnia caused by chronic respiratory failure were bridged to or through LVRS with low-flow VV ECLS (65 patients, group 1). Patients with preoperative normocapnia served as a control group (60 patients, group 2). In group 1, VV ECLS was implemented preoperatively in five patients and in 60 patients intraoperatively. Extracorporeal lung support was continued postoperatively in all 65 patients. Mean length of postoperative VV ECLS support was 3 ± 1 day. The 90 day mortality rate was 7.8% in group 1 compared with 5% in group 2 (p = 0.5). Postoperatively, a significant improvement was observed in quality of life, exercise capacity, and dyspnea symptoms in both groups. VV ECLS in patients with severe hypercapnia undergoing LVRS is an effective and well-tolerated treatment option. In particular, it increases the intraoperative safety, supports de-escalation of ventilatory strategies, and reduces the rate of postoperative complications in a cohort of patients considered "high risk" for LVRS in the current literature.

[Extracorporeal Lung Support in Thoracic Surgery: Basics and Pathophysiology]

Extracorporeal lung support (ECLS) is of increasing importance in general thoracic surgery. Different modes of ECLS may be applied in several situations throughout the perioperative phase and are adapted to the individual patient's needs and the planned surgical procedures. ECLS is not a static procedure and should be always evaluated according to the present condition of the patient. Therefore, it is essential to understand the pathophysiology of the disease and the different ECLS modes, as well as the different cannulation options, in order to be able to use the different escalation and de-escalation techniques in accordance with the clinical situation.

Effects of Bronchoscopic Lung Volume Reduction Coil Treatment on Arterial Blood Gases

BACKGROUND

Bronchoscopic lung volume reduction (BLVR) coil treatment is an increasingly used treatment modality for selected severe emphysema patients in recent years. Emphysema causes dynamic hyperinflation, loss of elastic recoil, air trapping, and decreased exercise capacity in advanced stages. This process progresses over time, leading to hypoxic and hypercapnic respiratory failure. The goal of this study is to elucidate the effects of BLVR coil treatment on arterial blood gas parameters in severe emphysema patients with respiratory failure.

METHODS

This is a retrospective study performed at a single pneumology center in Turkey. In total, this study included 39 patients diagnosed with severe emphysema who underwent bilateral BLVR coil treatment according to the general inclusion and exclusion criteria in the literature. The patients baseline and 12-month data were collected from medical records.

RESULTS

Twelve months after BLVR coil treatment, significant improvements were observed in patients' pulmonary function tests, an increase in partial pressure of oxygen in arterial blood (PaO2) from 58.05±9.36 to 73.82±13.3 (P<0.000) and decrease in partial pressure of carbon dioxide in arterial blood (PaCO2) of hypercapnic patients (from 51.60±4.1 to 46.55±6.6 mm Hg; P=0.001).

CONCLUSION

BLVR coil treatment is reliable and effective in emphysema patients who have hypoxic or mild hypercapnic respiratory failure. Besides improving lung function, BLVR coil treatment can significantly increase PaO2 and decrease PaCO2 in the medium term.

Principles and indications of extracorporeal life support in general thoracic surgery

The role of extracorporeal life support (ECLS) has expanded rapidly over the past 15 years to become an important tool in advanced general thoracic surgery practice. Intra-operative and in some cases continued post-operative ECLS is redefining the scope of complex surgical care. ECLS encompasses a spectrum of temporary mechanical support that may remove CO₂, oxygenate or provide hemodynamic support or a combination thereof. The most common modalities used in general thoracic surgery include extracorporeal membrane oxygenation (ECMO), interventional lung assist device (iLA^® Novalung^®, Heilbronn, Germany), and extracorporeal CO₂ removal (ECCO₂R). The ECMO and Novalung^® devices can be used in different modes for the short term or long-term support depending on the situation. In this review, the principles and current applications of ECLS in general thoracic surgery are presented.

Perioperative single-site veno-venous extracorporeal CO2 removal for minimally invasive giant bulla resection

Giant pulmonary bullae are rare and surgical management of patients with severe emphysema and advanced chronic obstructive lung disease (COPD) presenting with giant bullae can be very challenging. Previously, perioperative, two-site, high-flow, veno-venous extracorporeal membrane oxygenation (ECMO) was successfully utilized during giant bulla resection. Here we report the perioperative application of single-site, low-flow extracorporeal CO₂ removal (ECCO₂R) for minimally invasive thoracoscopic giant bulla resection. This approach of low-flow, veno-venous ECCO₂R, which is less invasive than conventional ECLS approaches, has enabled the safe performance of surgery and facilitated protective intraoperative single-lung ventilation while avoiding possible complications of aggressive mechanical ventilation.

Extracorporeal carbon dioxide removal (ECCO2R) in patients with acute respiratory failure

PURPOSE

To review the available knowledge related to the use of ECCO₂R as adjuvant strategy to mechanical ventilation (MV) in various clinical settings of acute respiratory failure (ARF).

METHODS

Expert opinion and review of the literature.

RESULTS

ECCO₂R may be a promising adjuvant therapeutic strategy for the management of patients with severe exacerbations of COPD and for the achievement of protective or ultra-protective ventilation in patients with ARDS without life-threatening hypoxemia. Given the observational nature of most of the available clinical data and differences in technical features and performances of current devices, the balance of risks and benefits for or against ECCO₂R in such patient populations remains unclear CONCLUSIONS: ECCO₂R is currently an experimental technique rather than an accepted therapeutic strategy in ARF-its safety and efficacy require confirmation in clinical trials.