We report the case of a 31-year-old, right-hand dominant female, who presented with critical ischaemia of the dominant hand following iatrogenic injury to the ulna artery at the wrist, during attempted venepuncture to monitor renal function (after a recent kidney infection). Past medical history included a clinical history of COVID-19 infection 5 months previously and occasional chronic pyelonephritis over 8 years. The patient was taking the combined oral contraceptive pill and her body mass index (BMI) was 25.7.The patient then applied a heartrate/motion tracker band to the wrist and the hand subsequently became cool, swollen, mottled and excruciatingly painful. Removal of the fitness tracker band did not improve matters (Figure 1(a)). She presented to the Emergency Department and a duplex ultrasound scan confirmed occlusion of the ulna artery at the wrist, with no flow through the radial artery and no distal run-off to the digits. Almost 24 hours after the initial venepuncture injury, the patient was referred to the plastic surgery service and underwent emergency exploration of the ulna artery. At operation, the artery was found thrombosed at the site of venepuncture. Thrombus was removed, the damaged segment resected and the artery successfully primarily anastomosed (Figure 1(b)). Despite early improvement and continuing patency of the ulna artery, the hand continued to demonstrate poor perfusion, particularly affecting thumb, index and middle fingers distally -interpreted to be related to distal thrombosis.The next day, an upper limb arteriogram was performed, which revealed absent perfusion of a 4-5 cm distal segment of the radial artery and no distal runoff in the digital vessels (Figure 1(c)). Thrombolysis treatment was commenced with tissue plasminogen activator infusion, through an indwelling brachial artery catheter demonstrating improvement in