A fastener for securing a medical or surgical line with respect to a patient, the fastener comprising: an elongate braided tubular sleeve for receiving the line therethrough, the sleeve having a variable length and being capable when lengthened of gripping the line, an attachment arrangement for attaching the sleeve to the patient, and a sensor mounted to the fastener, the sensor being arranged to sense at least one of a physiological parameter of the patient and a parameter in relation to the line.