Table 1.

Definitions of activities related to vital signs as reported in (Dall'Ora et al., 2020b).

Vital sign	One or more of the six physiological parameters that form the basis of the National Early Warning Score 2 scoring system (Royal College of Physicians, 2017): respiration rate, oxygen saturation, systolic blood pressure, pulse rate, temperature and level of consciousness or new confusion.
Vital signs equipment	Sphygmomanometer, manual blood pressure cuff, stethoscope, oxygen pulse oximeter, thermometer, electronic recording system for vital signs, tablets.
Vital signs documentation	Observing previous vital signs trends electronically or on paper, patient notes, track and trigger charts, other vital signs charts.
Vital signs set	The combined act of taking and recording the measurements of vital signs and sourcing vital signs equipment per patient. These can be complete (i.e. there is no reason for the observer to suppose that the six physiological parameters of vital signs as outlined in National Early Warning Score 2 have not all been completed) or incomplete (i.e. it is obvious to the observer that not all six physiological vital signs have been completed).
Vital signs round	One or more sets of individual vital signs taken sequentially by a single nurse are clustered in a vital signs round. Captures all parts of taking vital signs monitoring including using ‘Vital signs documentation’ and ‘Vital signs equipment’ as well as carrying out ‘Vital signs sets’.
Interruption	An act outside the process of ‘Vital signs’, and ‘Vital signs documentation’ – see “Vital signs related interruption” and “Non-vital-signs related interruption” for more information.
Vital signs related interruption	Interruptions that would not have occurred unless vital signs were being taken (e.g. cleaning vital signs monitoring equipment, sourcing alternative equipment when equipment was faulty, escalation to other staff members if vital signs were abnormal).
Non-vital-signs related interruption	Interruptions that are outside of the process of ‘Vital signs round’, for example the provision of personal care; the nurse leaving the patient to speak to someone else or to attend to other patients.