Patients undergoing cardiac surgery are at significant risk of postoperative pulmonary complications that may lead to prolonged ICU and hospital stay and increase mortality. The incidence of respiratory complications may be three to four times more common in patients with intrinsic respiratory disease and lower airway obstruction (including asthma or chronic obstructive pulmonary disease (COPD)), or obese patients or current heavy smokers (> 10 pack years).~High-flow nasal therapy (HFNT) is increasingly used as a non-invasive form of respiratory support. It delivers low level, flow-dependent positive airway pressure, and is much better tolerated by patients than alternatives such as continuous positive airway pressure (CPAP) or non-invasive ventilation. Patients can talk, eat, drink and walk whilst using HFNT. However, there is equipoise regarding its prophylactic use and effect on important patient-centred outcomes. Before the intervention is recommended for routine NHS use in cardiac surgery patients at high risk of pulmonary complications, whether it improves patient-related outcomes and is cost effective in a UK setting needs to be assessed.
NOTACS aims to determine if prophylactic use of high-flow nasal therapy (for a minimum of 16 hours after tracheal extubation) increases days at home in the first 90 days after surgery, for adult patients undergoing cardiac surgery who are at high risk of postoperative pulmonary complications. The study also incorporates a health economic analysis to estimate the incremental cost-effectiveness and cost-utility of HFNT versus standard oxygen therapy at 90 days, from the view-point of the public sector, NHS and patients.