The influence of differing inspired oxygen concentrations on platelet function in a model of lower limb ischaemic reperfusion injury

A trial of patients with a lower limb arterial tournique and whether an increase in inspired oxygen concentration at the time of reperfusion has any effect on platelet activation, as assessed by flow cytometry and thromboelastography

Status

Not yet recruiting

Phases

Unknown

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12610000139077

Acronym

SLIPPER

Enrollment

Registered

2010-02-10

Start date

2010-02-15

Completion date

Unknown

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

Evidence exists that surgery conducted with the use of a tourniquet results in blood being more prone to clotting. This phenomena starts whilst the tourniquet is inflated and increases when the tourniquet is deflated. Platelets are thought to be central to this process. Activation of the platelets may in part be due to products produced by the oxygen deprived tissue secondary to the use of the tourniquet. Some evidence exists that these products can be modified by altering the concentration of inspired oxygen at the time of reperfusion. However, whether altering the inspired concentration of oxygen influences platelet function remains unexplored. We plan to investigate whether changes in the inspired oxygen concentration alter platelet function in a model of ischaemic reperfusion injury. This is of clinical interest because ischaemic reperfusion injuries are encountered commonly in surgical practice. Examples include revascularisation of limbs in vascular surgery, organ transplantation, crush injuries etc. Maintenance of normal blood clotting is vital to clinical outcome.

Interventions

After randomization to a fractional inspired oxygen concentration of either 0.3, 0.5 or 0.8, the fractional inspired oxygen concentration is altered accordingly from 0.3 at the time of reperfusion. This is achieved by altering oxygen concentration on the ventilator. This is a one off treatment started 10 minutes before tourniquet release and continued until 24 hours after tourniquet release.

Study design

Allocation

Randomised controlled trial

Intervention model

Parallel

Primary purpose

Treatment

Masking

Blinded (masking used)

Eligibility

Sex/Gender

All

Age

18 Years to 80 Years

Healthy volunteers

Inclusion criteria

1. Adult patients undergoing lower limb surgery that requires the use of a tourniquet for more than 45 minutes 2. American Society of Anaesthesiology (ASA) grade 1 or 2

Exclusion criteria

1. Patients taking any antiplatelet medication 2. Confirmed coagulation disorder (pathological or drug induced) 3. Platelet count less then 80 x 109/l 4. Blood urea greater than 8.0 mmol/L 5. Systemic infection 6. Confirmed systemic Inflammatory diseases 7. Documented pregnancy 8. Documented malignancy 9. Trauma other than the ipsilateral lower limb 10. Multiple tourniquet episodes 11. Likely intraoperative O2 requirement > 30%

Outcome results