Non-invasive ventilation during surgery under neuraxial anaesthesia: a pathophysiological perspective on application and benefits and a systematic literature review

Abstract

Unlike general anaesthesia, neuraxial anaesthesia (NA) reduces the burden and risk of respiratory adverse events in the post-operative period. However, both patients affected by chronic obstructive pulmonary disease (COPD) and chest wall disorders and/or neuromuscular diseases may experience the development or the worsening of respiratory failure, even during surgery performed under NA; this latter negatively affects the function of accessory respiratory muscles, resulting in a blunted central response to hypercapnia and possibly in an exacerbation of cardiac dysfunction (NA-induced relative hypovolemia). According to European Respiratory Society (ERS) and American Thoracic Society (ATS) guidelines, non-invasive ventilation (NIV) is effective in the post-operative period for the treatment of both impaired pulmonary gas exchange and ventilation, while the intra-operative use of NIV in association with NA is just anecdotally reported in the literature. Whilst NIV does not assure a protected patent airway and requires the patient's cooperation, it is a handy tool during surgery under NA: NIV is reported to be successful for treatment of acute respiratory failure; it may be delivered through the patient's home ventilator, may reverse hypoventilation induced by sedatives or inadvertent spread of anaesthetic up to cervical dermatomes, and allow the avoidance of intubation in patients affected by chronic respiratory failure, prolonging the time of non-invasiveness of respiratory support (i.e., neuromuscular patients needing surgery). All these advantages could make NIV preferable to oxygen in carefully selected patients.

Emergency Awake Abdominal Surgery Under Thoracic Epidural Anaesthesia in a High-Risk Patient Within a Resource-Limited Setting

“…While EA use may be regarded as controversial in COPD patients, a study by van Lier et al showed that the theoretical effect of EA on respiratory muscle function by blunting intercostal nerve conduction was not clinically relevant [6]. EA as compared to spinal anaesthesia causes much fewer changes in inspiratory capacity and expiratory reserve volume [7]. EA also does not affect airway resistance and respiratory gas tensions and it has been shown to improve left ventricular function in high-risk patients by preserving ventricular pulmonary coupling resulting in an improved myocardial oxygen balance [7][8][9].…”

“…EA as compared to spinal anaesthesia causes much fewer changes in inspiratory capacity and expiratory reserve volume [7]. EA also does not affect airway resistance and respiratory gas tensions and it has been shown to improve left ventricular function in high-risk patients by preserving ventricular pulmonary coupling resulting in an improved myocardial oxygen balance [7][8][9]. GA with tracheal intubation and altered respiratory mechanics may lead to a vulnerable state for right ventricular dynamics.…”

“…This may be further compounded by the direct cardiodepressant effects of anaesthetic agents on myocardial function [9]. Furthermore, GA affects functional residual capacity, worsens ventilation-perfusion (V:Q) mismatch, and impairs diaphragmatic function [7]. Hence, in high-risk patients such as those with COPD who are at heightened risk of right ventricular dysfunction and adverse ventilatory effects under GA, it is reasonable to advocate for locoregional techniques to be implemented.…”

“…A recent systematic review highlights the potential role of intraoperative NIV in patients with respiratory compromise undergoing surgery using neuraxial anaesthesia [7]. These benefits include the reversal of alveolar hypoventilation, prevention or treatment of respiratory failure in "at risk" patients, and improvement of V:Q mismatch [7].…”

“…A recent systematic review highlights the potential role of intraoperative NIV in patients with respiratory compromise undergoing surgery using neuraxial anaesthesia [7]. These benefits include the reversal of alveolar hypoventilation, prevention or treatment of respiratory failure in "at risk" patients, and improvement of V:Q mismatch [7]. However, caution is warranted when using NIV in certain instances: patients with altered levels of consciousness, severe respiratory compromise warranting immediate intubation, gastric distention, non-cooperative patients, and inability to clear respiratory secretions [7].…”