Surgical Tourniquets and Cerebral Emboli

Surgical Tourniquets and Cerebral Emboli Pilot Study

BACKGROUND In 2012 76,497 primary total knee (TKR) replacements were performed in England, Wales and Northern Ireland . Traditionally TKR surgery is undertaken with the aid of a surgical tourniquet. A surgical tourniquet is an occlusive device applied around a patient's leg. The tourniquet squeezes the leg (including blood vessels within the leg) and can therefore reduce the amount of bleeding that occurs while it is inflated. An intraoperative tourniquet can therefore help to improve the surgical field of view. Although the majority of surgeons prefer to undertake TKR surgery using a tourniquet a small but increasing number are now not pursuing these devices.

There is robust evidence that the risk of deep vein thrombosis is increased if a tourniquet is used for TKR surgery. In addition embolic material in the venous system have been observed following TKR surgery and have been noted to be present in the right atrium with transoesophageal (TOE) echo intra-operatively. , Significant and potentially life threatening emboli have been documented to enter the cerebral circulation via pulmonary arterio-venous shunts and patent foramen ovale (PFO) (27% of patients at autopsy) , . The clinical manifestations of cerebral emboli post tourniquet deflation in TKR are not fully understood. Fat embolism syndrome and post-operative confusion in TKR patients may be the result of emboli formed during a TKR. ,

AIM

• Is there evidence of emboli entering the cerebral circulation following tourniquet deflation in TKR surgery?
• Is there evidence of MRI detectable brain lesions and or any clinical change in cognition compared in patients undergoing TKR surgery with a tourniquet compared to those that do not have a tourniquet?

Study Overview

• Status: Completed
• Conditions: Osteoarthritis; Trauma; RA

• Study Type: Observational
• Enrollment (Actual): 12

Contacts and Locations

Study Locations

• United Kingdom
  • Coventry, United Kingdom, CV2 2DX
    • University Hospital Warwickshire and Coventry

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Patients who are due to have a total knee replacement.

Description

Inclusion Criteria:

• i.Aged >18
• ii.Undergoing elective TKR
• iii.Able to give written informed consent
• iv.No contraindications to MR imaging

Exclusion Criteria:

• i. Ages <16
• ii. Not able to give written informed consent
• iv. Contraindications to MR imaging

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Total knee replacement patients; Patients who are due to have a total knee replacement will be studied to look for the presence of Emboli. Observational with imaging.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Emboli on Transcranial Doppler	2 independent technicians will verify the number of emboli detected. Non-invasive	Intra-operative
MRI brain scan - presence of Emboli	Reviewed by Professor of radiology - presence, number and volume of diffusion weighted lesions	Post-operatively, prior to discharge

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mini-mental state examination	Set of 30 questions which test cognitive function	Pre-operative vs Post-operative

Collaborators and Investigators

• Sponsor: University Hospitals Coventry and Warwickshire NHS Trust
• Investigators: Principal Investigator: Victoria Gibbs, BA, MBBS, UHCW

Publications and helpful links

General Publications

• Tai TW, Lin CJ, Jou IM, Chang CW, Lai KA, Yang CY. Tourniquet use in total knee arthroplasty: a meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2011 Jul;19(7):1121-30. doi: 10.1007/s00167-010-1342-7. Epub 2010 Dec 15.
• Parmet JL, Horrow JC, Pharo G, Collins L, Berman AT, Rosenberg H. The incidence of venous emboli during extramedullary guided total knee arthroplasty. Anesth Analg. 1995 Oct;81(4):757-62. doi: 10.1097/00000539-199510000-00017.
• Parmet JL, Berman AT, Horrow JC, Harding S, Rosenberg H. Thromboembolism coincident with tourniquet deflation during total knee arthroplasty. Lancet. 1993 Apr 24;341(8852):1057-8. doi: 10.1016/0140-6736(93)92414-o.
• Arroyo JS, Garvin KL, McGuire MH. Fatal marrow embolization following a porous-coated bipolar hip endoprosthesis. J Arthroplasty. 1994 Aug;9(4):449-52. doi: 10.1016/0883-5403(94)90057-4.
• Pugsley W, Klinger L, Paschalis C, Treasure T, Harrison M, Newman S. The impact of microemboli during cardiopulmonary bypass on neuropsychological functioning. Stroke. 1994 Jul;25(7):1393-9. doi: 10.1161/01.str.25.7.1393.
• Riding G, Daly K, Hutchinson S, Rao S, Lovell M, McCollum C. Paradoxical cerebral embolisation. An explanation for fat embolism syndrome. J Bone Joint Surg Br. 2004 Jan;86(1):95-8.
• Caillouette JT, Anzel SH. Fat embolism syndrome following the intramedullary alignment guide in total knee arthroplasty. Clin Orthop Relat Res. 1990 Feb;(251):198-9.

Study record dates

Study Major Dates

• Study Start: September 1, 2014
• Primary Completion (Actual): April 1, 2015
• Study Completion (Actual): April 1, 2015

Study Registration Dates

• First Submitted: September 15, 2014
• First Submitted That Met QC Criteria: September 15, 2014
• First Posted (Estimate): September 16, 2014

Study Record Updates

• Last Update Posted (Estimate): June 30, 2015
• Last Update Submitted That Met QC Criteria: June 28, 2015
• Last Verified: June 1, 2015

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Embolism and Thrombosis; Intracranial Embolism and Thrombosis; Thromboembolism; Intracranial Embolism
• Other Study ID Numbers: STCE2.0