Lung injury following cardiopulmonary bypass: a clinical update

ABSTRACT

Introduction

Cardiopulmonary bypass (CPB) is an integral component of cardiac surgery; however, one of its most critical complications is acute lung injury induced by multiple factors including systemic inflammatory response.

Areas covered

The objective of this review is to investigate the multiple factors that can lead to CPB-induced lung injury. These include contact of blood components with the artificial surface of the CPB circuit, local and systemic inflammatory response syndrome (SIRS), lung ischemia/re-perfusion injury, arrest of ventilation, and circulating endotoxins. We also focus on possible interventions to curtail the negative impact of CPB, such as off-pump surgery, impregnation of the circuit with less biologically active substances, leukocyte depletion filters and ultrafiltration, and pharmacological agents such as steroids and aprotinin.

Expert Opinion

Although many aspects of CPB are proposed to contribute to lung injury, its overall role is still not clear. Multiple interventions have been introduced to reduce the risk of pulmonary dysfunction, with many of these interventions having shown promising results, significantly attenuating inflammatory mediators and improving post-operative outcome. However, since lung injury is multifactorial and affected by inextricably linked components, multiple interventions tackling each of them is required.

KEYWORDS:

• Cardiopulmonary bypass (CPB)
• lung injury
• systemic inflammatory response syndrome (SIRS)

Article highlights

• Although cardiopulmonary bypass has been linked with lung injury, the precise mechanisms are uncertain.

• The artificial surfaces of the cardiopulmonary bypass circuit, local inflammation and systemic inflammatory response syndrome, lung ischemia/re-perfusion injury, arrest of ventilation, and circulating endotoxins have all been implicated in driving lung injury.

• Various interventions have been considered to ameliorate lung damage during cardiac surgery including off-pump surgery, impregnation of the circuit with less biologically active substances, leukocyte depletion filters and ultrafiltration, and pharmacological agents.

• Although certain interventions show promising results, lung injury is multifactorial and affected by inextricably linked components.

• To truly prevent lung injury, it may be necessary to institute multiple interventions so that each inflammatory pathway is attenuated.

Declaration of Interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.