Coronary Artery Surgery and Extracorporeal Circulation: The Search for a New Standard

Induced blood oxidation in myocardial revascularization

Background: The use of artificial circulation in surgical myocardial revascularization is one of the key pathogenetic factors in the development of the oxidative stress and systemic inflammatory response in the postoperative period. Aims: the purpose of the study was to describe the dynamics of the induced blood oxidation parameters during coronary artery bypass surgery in the conditions of artificial circulation and on the working heart. Methods: The study included 64 patients who underwent coronary bypass surgery, with 31 (48.4%) on-pump patients and 33 (51.6%) off-pump patients. The oxidative stress simulations were conducted under the in vitro conditions. The blood oxidation-induced values were studied using a biological oxygen monitor. Results: In patients with coronary heart disease, regardless of the choice of the revascularization method (on-pump / off-pump), we observed statistically significantly (p 0.05) higher initial and maximum blood oxidation rates, the oxidative activity factor, and a shorter initiation period than those in healthy volunteers. No significant differences were found by the inter-group comparison analysis both 10 days and 6 months post-surgery. Conclusion: The indicators of induced blood oxidation do not depend on the method of revascularization during coronary bypass grafting (artificial circulation or a working heart). The changes in the parameters indicating activation of the oxidative and antioxidant blood systems may be transient by their nature and occur in the early postoperative period.

Extracorporeal Oxygenation Techniques in Adult Critical Airway Obstruction: A Review

Extracorporeal life support has been increasingly utilized in different clinical settings to manage either critical respiratory or heart failure. Complex airway surgery with significant or even total perioperative airway obstruction represents an indication for this technique to prevent/overcome a critical period of severe hypoxaemia, hypoventilation, and/or apnea. This review summarizes the current published scientific evidence on the utility of extracorporeal respiratory support in airway obstruction associated with hypoxaemia, describes the available methods, their clinical indications, and possible limitations. Extracorporeal membrane oxygenation using veno-arterial or veno-venous mode is most commonly employed in such scenarios caused by endoluminal, external, or combined obstruction of the trachea and main bronchi.

Extracorporeal support in airway surgery

Extracorporeal life support (ECLS) is increasingly used for major airway surgery. It facilitates complex reconstructions and maintains gas exchange during endoscopic procedures in patients with critical airway obstruction. ECLS offers the advantage of an uncluttered surgical field and eliminates the need for crossing ventilation tubes, thus, making precise surgical dissection easier. ECLS is currently used for hemodynamic and respiratory support in lung transplantation as well as extended tumor resections with an acceptable risk profile. This work reviews the published experience of ECLS in airway surgery both in adults and in pediatric patients. It highlights currently available devices and their indications.

A multidisciplinary perioperative strategy for attaining "more physiologic" cardiac surgery

BACKGROUND

Cardiac surgery is, by definition, a "non-physiologic" intervention associated with systemic adverse effects. Despite advances in surgical technique, cardiopulmonary bypass (CPB) technology as well as anaesthesia management and patient care, there is still significant morbidity and subsequent mortality.

AIM

We consider that the contemporary demand for further improving patient outcome mandates the upgrade from optimal perfusion during the procedure as the gold standard to the concept of a "more physiologic" cardiac surgery. Our policy is a multidisciplinary perioperative strategy based on goal-directed perfusion throughout surgery incorporating in-line monitoring. This translates to "prevent rather than correct" malperfusion through real-time adjustment rather than correction of derangement detected late by incremental evaluation.

METHOD

The strategy is based on continuous monitoring of cardiac index, SvO₂, DO₂i, DO₂i/VCO₂i and rSO₂. Data acquisition is followed by action when needed; this includes stepwise: transfusion, increase of cardiac output and initiation of inotropic/vasoactive support. Moreover, implementation of minimally invasive extracorporeal circulation (MiECC) is considered as a fundamental component of physiologic perfusion when on-CPB, providing improved circulatory support and end-organ protection.

CONCLUSION

We consider that, with this strategy which establishes optimal perfusion perioperatively, we attain the goal of a "more physiologic" cardiac surgery.

Elective Use of Veno-venous Extracorporeal Membrane Oxygenation and High-flow Nasal Oxygen for Resection of Subtotal Malignant Distal Airway Obstruction

We describe the use of peripheral veno-venous extracorporeal membrane oxygenation (VV ECMO) and high-flow nasal oxygen as procedural support in a patient undergoing debulking of a malignant tumour of the lower airway. Due to the significant risk of complete airway obstruction upon induction of anaesthesia, ECMO was established while the patient was awake, and was maintained without systemic anticoagulation to minimise the risk of intraoperative bleeding. This case illustrates that ECMO support with high-flow nasal oxygen can be considered as part of the algorithm for airway management during surgery for subtotal lower airway obstruction, as it may be the only viable option for maintaining adequate gas exchange.

Miniaturized versus conventional cardiopulmonary bypass in high-risk patients undergoing coronary artery bypass surgery

Objective: To review our results with the use of miniaturized cardiopulmonary bypass (Mini-CPB) versus conventional cardiopulmonary bypass (C-CPB) in high-risk patients (additive EuroSCORE≥6) who have undergone coronary artery bypass graft surgery (CABG).

Patients and methods: This study includes a consecutive series of 236 patients with an additive EuroSCORE≥6 who underwent CABG, employing either C-CPB or Mini-CPB. Propensity score analysis was performed.

Results: The study groups had similar EuroSCOREs. Stroke rate was significantly higher among C-CPB patients (5.4% vs. 0%, p=0.026). In-hospital mortality (4.8% vs. 3.4%, p=0.75) and combined adverse end-point rate were higher in C-CPB patients (20.4% vs. 13.5%, p=0.18). Postoperative bleeding and need for transfusion were similar in the study groups, but re-sternotomy for bleeding was more frequent among C-CPB patients (4.8% vs. 1.1%, p=0.26). Seventy-four propensity matched pairs had similar immediate postoperative results: C-CPB patients had higher mortality (6.8% vs. 4.1%, p=0.72), stroke (5.4% vs. 0%, p=0.12) and combined adverse end-point rates (27.0% vs. 16.2%, p=0.11), but such differences failed to reach statistical significance.

Conclusions: Mini-CPB achieved somewhat better results than C-CPB in these high-risk patients undergoing isolated CABG. This study confirmed that cerebral protection could be the main benefit associated with the use of Mini-CPB.

Outcome after coronary artery bypass surgery with miniaturized versus conventional cardiopulmonary bypass

We have reviewed the results of our experience with the use of miniaturized (Mini-CPB) versus conventional (C-CPB) cardiopulmonary bypass in coronary artery bypass surgery (CABG). This study included 365 patients who underwent CABG with C-CPB and 101 patients with Mini-CPB. In-hospital mortality was lower in the C-CPB group (1.4% vs. 3.0%, P = 0.38). A better, but not statistically significant, immediate outcome was observed in the C-CPB group as indicated by a shorter length of stay in the intensive care unit as well as a lower incidence of combined adverse end-point. However, this was probably due to significantly higher operative risk in the Mini-CPB group (logistic EuroSCORE: 8.5 ± 10.0 vs. 4.6 ± 7.1, P < 0.0001). Seventy-seven propensity score-matched pairs had similar immediate postoperative results after Mini-CPB and C-CPB (30-day mortality: 1.3% vs. 1.3%; stroke: 0% vs. 0%; intensive care unit stay ≥5 days: 6.5% vs. 9.1%; combined adverse events: 14.3% vs. 11.7%). Mini-CPB achieves similar results to C-CPB in patients undergoing isolated CABG. The potential efficacy of Mini-CPB is expected to be more evident in high-risk patients or in complex cardiac surgery requiring much longer cardiopulmonary perfusion.