None listed
Conditions
Brief summary
Apnoeic oxygenation is the delivery of oxygen to the lungs without causing the lungs to inflate. Whereas, low tidal volume ventilation is the delivery of oxygen to the lungs that causes the lungs to partially inflate and deflate. Both are established anaesthetic techniques that have been used for over fifty years and are used routinely in many surgical procedures to allow easier access to different structures in the chest. During cardiac artery bypass graft surgery (open heart surgery to bypass blocked arteries of the heart), the most common artery used to bypass blocked arteries is the left internal mammary artery (LIMA). This artery is has been proven to be the best option for short and long term survival after cardiac surgery. This artery is 15-26cm long and runs straight down the left side of the breastbone. The use of apnoeic oxygenation and low tidal volume ventilation are used as routine techniques to allow safe surgical access of the LIMA. Currently, there are no studies comparing apnoeic oxygenation to a low tidal volume strategy in a cardiac setting. It is unknown what the effects of these techniques are on levels of oxygenation and carbon dioxide on the vessels in the lungs, or on the function of the heart. In this study, we aim to compare the usefulness and safety of apnoeic oxygenation to a low tidal volume ventilation technique during dissection of the left internal mammary artery. There will be no additional requirements of the participant or deviation from standard surgical and anaesthesia care except for the additional sampling of 8mL (approximately two teaspoons) of blood from an artery in the wrist. This will allow for the additional measurements of oxygen and carbon dioxide. This study will help us determine if one technique (apnoeic oxygenation or low tidal volume ventilation) is better than the other. If so, that technique could be adopted as standard of care in this setting for all patients. A total of 24 subjects will be included at the Austin Hospital.
Interventions
In patients undergoing coronary artery bypass surgery who require harvesting of the left internal mammary artery; the intervention arm will be low tidal volume ventilation during the first 15 minutes of the surgical harvest of the left internal mammary artery. The low tidal volume ventilation will be at 2.5mL/kg of ideal body weight with 100% oxygen. There will be no additional requirements of the participant or deviation from standard surgical and anaesthesia care except for the additional samp
In patients undergoing coronary artery bypass surgery who require harvesting of the left internal mammary artery; the intervention arm will be low tidal volume ventilation during the first 15 minutes of the surgical harvest of the left internal mammary artery. The low tidal volume ventilation will be at 2.5mL/kg of ideal body weight with 100% oxygen. There will be no additional requirements of the participant or deviation from standard surgical and anaesthesia care except for the additional sampling of 8mL (approximately two teaspoons) of blood from an artery in the wrist. This will allow for the additional measurements of oxygen and carbon dioxide.
Sponsors
Departments of Intensive Care and Anaesthesia, Austin Hospital
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Patients will be eligible to participate in this study if: 1. The patient is aged 18 years or older 2. The patient is undergoing elective coronary artery bypass surgery requiring harvesting of the left internal mammary artery as part of standard of care 3. The patient will have an arterial line inserted for routine monitoring of blood pressure during the surgical procedure 4. The patient will have transoesophageal echocardiography as routine standard of care.
Exclusion criteria
Patients will be ineligible for participation if: 1. The patient is less than 18 years 2. The patient is undergoing emergency coronary artery bypass surgery 3. The patient is undergoing a non-coronary artery bypass surgery 4. The patient has chronic lung disease (KCO/TLCO/FEV1 <50% predicted) 5. The patient has moderate pulmonary hypertension (MPA >40mmHg) 6. The patient has super obesity (BMI>50kg/m2) 7. The patient is pregnant. 8. The patient has an ASA (American Society of Anesthesiologists) physical status V
Outcome results
None listed