None listed
Conditions
Brief summary
Support of the circulation during heart surgery using the heart-lung bypass machine is inevitably associated with organ damage and associated reduced function. This is due to reduced blood flow (ischaemia), the effects of restoration of flow (reperfusion injury) and the subsequent inflammation that is caused. The body has its own way of protecting itself against reduced blood flow and oxygen by a mechanism known as preconditioning. In essence, brief periods of mild ischaemia are protective against a subsequent more severe episode of ischaemia. These periods of mild ischaemia can be of the organ itself or of another organ in the body. For example ischaemia of the leg can protect the heart against ischaemia, so called “remote preconditioning”. We have shown in animal and human models that remote preconditioning using a tourniquet placed around the leg for brief periods (similar in duration to when taking blood samples from children) reduces the amount of injury to heart muscle by 50% and also leads to improved heart and lung function. We have shown that remote preconditioning in a similar way protects the organs of a heterogeneous group of children undergoing cardiac surgery, resulting in better function of the heart and lungs and also a reduction of the inflammatory response to the heart-lung machine. This could potentially reduce the problems in looking after children after surgery and also reduce the amount of time spent on the intensive care unit. We intend to study a more uniform group of patients undergoing cardiac surgery in the neonatal period. All interventions will be performed during the period of routine general anaesthesia at the time of surgical repair. We will study the degree of organ injury induced by heart-lung bypass using standard intensive care parameters and equipment for measuring lung function. In addition, the degree heart muscle death and inflammation will be assessed by blood tests. Samples will be taken from indwelling catheters routinely placed at the time of surgery and not require additional venepuncture. Measurements will be made prior to surgery and also at set time intervals in the first 24 hours postoperatively to determine the evolution of effects.
Interventions
Preconditioning as a method of myocardial protection at the time of repair of congenital heart disease. Patients will be randomised to control or remote ischaemic preconditioning. The remote ischaemic preconditioning protocol will be by 4 cycles of 5 minutes of lower limb ischaemia induced by inflating a blood pressure cuff to 15 mmHg greater than systolic blood pressure placed around the thigh, followed by 5 minutes of reperfusion.
Sponsors
Study design
Eligibility
Inclusion criteria
Neonates undergoing open heart surgery for repair of congenital defects will be recruited. Specifically, children undergoing the arterial switch procedure and the Norwood procedure will be studied.
Exclusion criteria
Patients with chromosomal defects, associated congenital lung malformations, and haematological disorders and those older than 28 days will be excluded.