A fastener for securing a medical or surgical line with respect to a patient, the fastener comprising an elongate braided tubular sleeve 610 for receiving the line therethrough, the sleeve 610 having a variable length and being capable when lengthened of gripping the line. An attachment arrangement 616,618 for attaching the sleeve 610 to the patient, and a sensor 620 mounted to the fastener, the sensor 620 being arranged to sense at least one of a physiological parameter of the patient and a parameter in relation to the line. The physiological parameter maybe blood pressure, heart rate, blood sugar level, blood pH level, blood oxygen level, skin translucence, skin conductance, or skin temperature. The parameter in relation to the line may comprises the fluid flow rate, fluid oxygenation level, fluid temperature, pH level, dissolved gas concentration, age of the line, time since last time the line was replaced, or bacteria level.
