Table 1.
Task scenario for usability testing
| Tasks | Participants (N = Nurse, D = Doctor) | Detailed sub-tasks | Equipment/keys/knobs/dials/screen, etc. |
|---|---|---|---|
| Ventilator set up and check prior to receiving patient | |||
| Assemble circuit | N1 + D1 | Check for integrity of valves/diaphragms, etc. | Ventilator; test equipment (e.g. test lung, flow sensor calibration equipment); power supply |
| Install circuit onto ventilator | Connect to test simulator (test lung) and perform self-test | ||
| Set up ventilator to patient-specific parameters | Choose mandatory mode, set inspiratory pressure or tidal volume (IBW based) according to mode. Respiratory rate, I:E ratio (if adjustable) FiO2 and PEEP | ||
| Check alarms (disconnect, high pressure, apnoea, volume alarms, O2 supply and battery level). Change alarm parameters | Disconnect, high pressure, apnoea, volume alarms, O2 supply and battery level. Change alarm parameters. | ||
| Perform leak test and test patency of circuit with all parts attached (incl. filters) | |||
| Check integrity and function of flow sensors Oxygen calibration | |||
| Initiation of mechanical ventilation and adjust to initial parameters | |||
| Intubation of patient, attach to ventilator, initiating and confirming safe ventilation. | N1 + D1 + D2 + runner | Complex process, separate evaluation, outside of scope of this evaluation | Airway trolley; ventilator; monitor; Sim Man/lung |
| Initiate ventilation and confirm safe delivery of set ventilator parameters | N1 or D1 | Assess tidal volume, peak/plateau airway pressure, PEEP, FiO2, respiratory rate as displayed by ventilator | |
| Adjust respiratory rate and I:E ratio (if adjustable) | N1 or D1 | ||
| Rapidly increase or decrease FiO2 | N1 | ||
| Optimise PEEP | N1 or D1 | Sequential adjustments to improve oxygenation and titrate to compliance | |
| React to sudden change in status and alarms | |||
| Respond to low supply pressure alarm | Evaluate integrity of supply pressure, look for disconnection | ||
| Respond to high airway pressure alarm | Systematic evaluation from patient to ventilator | Monitor; ventilator; Sim Man/lung | |
| Respond to low airway pressure alarm (circuit or patient disconnection) | Systematic evaluation from patient to ventilator looking for leaks or disconnections | ||
| Rapidly adjust FiO2 in response to desaturation or enable suction | Single button (O2 flush) or complex step involving adjustment of FiO2 | ||
| Respond to volume alarms | High Vt or low Vt or MV | ||
| Respond to apnoea alarm | Ensure backup mode initiates | ||
| Respond to low battery or power disconnection | Identify source of power | ||