Nasal Oxygen Therapy After Cardiac Surgery (NOTACS)

Effect of High-Flow Nasal Therapy on Patient-Centered Outcomes in Patients at High Risk of Postoperative Pulmonary Complications After Cardiac Surgery: A Multicentre Randomised Trial

NOTACS aims to determine if prophylactic use of high-flow nasal therapy (for a minimum of 16 hours after tracheal extubation, inclusive of up to one hour off randomised therapy for transfers around the hospital and/or physio mobilisation) 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.

Study Overview

• Status: Completed
• Conditions: Coronary Artery Disease; Respiratory Failure; Cardiac Valve Disease
• Intervention / Treatment: Device: High Flow Nasal Therapy

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 1280
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Cambridgeshire
    • Cambridge, Cambridgeshire, United Kingdom, CB20AY
      • Royal Papworth Hospital NHS Foundation Trust

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Aged 18 years or over.
• Undergoing any elective or urgent first-time or redo cardiac surgery performed on cardiopulmonary bypass
• Have one or more clinical risk factors for postoperative pulmonary complications (COPD, asthma, lower respiratory tract infection in last 4 weeks as defined by use of antibiotics, body mass index ≥35 kg/m2 , current (within the last 6 weeks) heavy smoker (> 10 pack years)) (47, 48).

Asthma is a disease characterized by recurrent attacks of breathlessness and wheezing, and patients will have been prescribed medication by inhalers or nebulisers (either bronchodilators or steroids).

Chronic Obstructive Pulmonary Disease (COPD) is an umbrella term used to describe chronic lung diseases that cause limitations in lung airflow. The more familiar terms 'chronic bronchitis' and 'emphysema' are no longer used but are now included within the COPD 13 diagnosis. The most common symptoms of COPD are breathlessness, or a 'need for air', excessive sputum production, and a chronic cough. Patients suitable for the NOTACS study will have been prescribed medication by inhalers or nebulisers (either bronchodilators or steroids).

Exclusion Criteria:

• Requiring home oxygen therapy.
• Deep hypothermic circulatory arrest planned
• Contraindication to HFNT, e.g. nasal septal defect.
• Requirement for home ventilatory support (including: HFNT, CPAP, BiPAP)
• Requiring emergency cardiac surgery defined as surgery required within 24 hours of the decision to operate.
• Patients not fluent in English.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Standard Oxygen Therapy; Standard oxygen therapy arm patients will be given 30-40% inspired O2 and flow 2-6 l/min via nasal prongs or non-rebreathing mask (not humidified and not heated) post extubation. Monitoring of saturations, respiratory rate and arterial gases will happen 15 minutes post extubation and then as per local policy thereafter. If saturations < 93% then FiO2 will be increased as per respiratory escalation protocol. Standard oxygen therapy will be given for a minimum of 16 hours post extubation.
Other: High-Flow Nasal Therapy; High-flow nasal therapy arm patients will be given AIVRO 2 high flow oxygen therapy machines post extubation, start at 30-40% inspired O2 and flow 30 l/min then up to 50 l/min over 5-10 min. Monitoring of saturations, respiratory rate and arterial gases will happen after 15 minutes post extubation and then as per local policy thereafter. If saturations < 93% then increase FiO2 as per respiratory escalation protocol. High flow nasal therapy will be given for a minimum of 16 hours post extubation.	Device: High Flow Nasal Therapy; High Flow Nasal Oxygen (Airvo2 Device)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incremental cost-effectiveness and cost-utility of High flow nasal therapy versus Standard therapy for patients undergoing cardiac surgery who are at high risk of postoperative pulmonary complications at 90 days	Health Economic analysis to estimate the incremental cost-effectiveness and cost-utility of High flow nasal therapy versus Standard therapy at 90 days from the view point of the public sector, NHS and patient, measured by using Patient and Family Resource Use patient facing Questionnaires at 90 days.	90 days
Days alive and at home without additional support in the first 90 days after surgery, for adults at high risk of postoperative pulmonary complications undergoing cardiac surgery who either receive High Flow Nasal Oxygen Therapy or Standard Oxygen Therapy	Number of days at home without additional support in the first 90 days after surgery (relative to baseline location and support), measured by the patient facing Patient Location and Medication Diary at 90 days	90 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Estimates of the incremental cost-effectiveness and cost-utility of High flow nasal therapy versus standard oxygen therapy for adult patients undergoing cardiac surgery who are at high risk of postoperative pulmonary complications at 30 days.	Health Economic analysis to estimate the incremental cost-effectiveness and cost-utility of High flow nasal therapy versus Standard therapy at 90 days from the view point of the public sector, NHS and patient, measured by using Patient and Family Resource Use patient facing Questionnaires at 30 days.	30 days
Incidence of mortality, pulmonary complications, intensive care re-admission rate, length of hospital and intensive care stay .	Mortality measured by the incidence of death reported from patient follow-up and medical records at 30 and 90 days. Incidence of postoperative pulmonary complications measured using medical notes during primary admission to hospital. ICU re-admission rate measured using the in-patient diary eCRF at any time during primary hospital admission Length of ICU stay (days) measured using the in-patient diary eCRF during primary hospital admission Length of hospital stay (days) measured using the in-patient diary eCRF during primary hospital admission	Discharge on average 7 days post operation, 30 and 90 days
Incidence of major complications including sepsis, renal failure, myocardial infarction and stroke.	Incidence of stroke measured from patient follow-up and medical records at 30 and 90 days Incidence of sepsis measured from patient follow-up and medical records at 30 and 90 days Incidence of myocardial infarction measured from patient follow-up and medical records at 30 and 90 days	30 and 90 days
Incidence of readmission to hospital rate.	Incidence of readmission to hospital rate, measured using the in-patient diary eCRF during primary hospital admission and patient location and medication diary for patient completion up to 90 days	90 days
Statistical analysis of oxygenation as measured by the ROX Index (as defined as Sp02/Fi02 to respiratory rate ratio).	Oxygenation measured by ROX Index (defined as Sp0₂/Fi0₂ to respiratory rate ratio) at 2, 6, 12, 24 and 48 hours post-extubation	2,6,12,24,and 48 hours post extubation
Statistical analysis of patient-centered outcomes as measured using the EQ-5D-5L Quality of Survival	Quality of Survival will be as measured using ED-5D-5L Quality adjusted life years (QALYs).	Discharge on average 7 days post operation, 30 and 90 days
Statistical Analysis to determine if prophylactic use of high- flow nasal oxygen reduces health service and resource use.	Health service and resource use measured using Patient and Family Resource Use Questionnaires at baseline, discharge, 30 and 90 days	Discharge on average 7 days post operation, 30 and 90 days
Statistical analysis of patient level of assistance needed with activities of daily living post surgery as measured using BARTHEL questionnaire.	Patient level of assistance needed with activities of daily living, measured using the BARTHEL questionnaire at baseline, discharge, 30 and 90 day	Discharge on average 7 days post operation, 30 and 90 days
Statistical analysis of patient-centered outcomes as measured using the EQ-5D-5L	Patient-reported outcomes measured using the EQ-5D-5L questionnaire at baseline, discharge, 30 and 90 days 12. Quality of Survival will be as measured using ED-5D-5L Quality adjusted life years (QALYs).	Discharge on average 7 days post operation, 30 and 90 days

Collaborators and Investigators

• Sponsor: Papworth Hospital NHS Foundation Trust
• Collaborators: King's College London; University Hospitals, Leicester
• Investigators: Principal Investigator: Andrew Klein, Royal Papworth Hospital NHS Foundation Trust

Study record dates

Study Major Dates

• Study Start (Actual): September 8, 2020
• Primary Completion (Actual): December 6, 2024
• Study Completion (Actual): December 6, 2024

Study Registration Dates

• First Submitted: May 8, 2021
• First Submitted That Met QC Criteria: March 24, 2022
• First Posted (Actual): April 4, 2022

Study Record Updates

• Last Update Posted (Actual): May 29, 2025
• Last Update Submitted That Met QC Criteria: May 22, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: Cardiac Surgery; Pulmonary Complications; High-Flow Nasal Therapy; High-Flow Nasal Oxygen
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Heart Diseases; Respiratory Tract Diseases; Respiration Disorders; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Myocardial Ischemia; Respiratory Insufficiency; Coronary Artery Disease; Heart Valve Diseases
• Other Study ID Numbers: P02590

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No