Table 1 Clinical vignettes to prompt discussion in interviews

Vignette 1: Child with a severe neurodisability being seen in an outpatient clinic

Part 1: You are seeing a 7-year-old boy with GMFCS V cerebral palsy of unknown cause, and associated epilepsy who requires gastrostomy feeding. This outpatient clinic review is approximately four weeks after a recent prolonged inpatient admission where he had a serious illness requiring non-invasive ventilatory support (no previous requirement for respiratory support at home)

Part 2: His parents have seen on multiple parent blogs about the role of extracorporeal membrane oxygenation (ECMO) in critical illnesses and would like to document their preference for ECMO if he has another serious illness

Vignette 2: Child with a severe neurodisability admitted in the intensive care unit

Part 1: You are taking over responsibility for a 7-year-old boy with GMFCS V cerebral palsy of unknown cause, and associated epilepsy who requires gastrostomy feeding. This boy was admitted to PICU one week ago with a serious illness requiring non-invasive ventilatory support that has not been able to be weaned (no previous requirement for respiratory support at home)

Part 2: His parents have seen on multiple parent blogs about the role of extracorporeal membrane oxygenation (ECMO) in critical illnesses and would like to document their preference for ECMO during this illness

Vignette 3: Child with a solid tumour

Part 1: You are seeing a 5-year-old girl with relapsed, widely metastatic neuroblastoma who is currently well and not on treatment

Part 2: Her parents have seen on multiple parent blogs about the role of extracorporeal membrane oxygenation (ECMO) in critical illnesses and would like to document their preference for ECMO if she has another serious illness

Vignette 4: Child with a haematological malignancy

Part 1: You are seeing an 8-year-old boy with multiply relapsed AML, who has been diagnosed with a subsequent relapse four months following second HSCT. He is clinically well and not currently on treatment

Part 2: His parents have seen on multiple parent blogs about the role of extracorporeal membrane oxygenation (ECMO) in critical illnesses and would like to document their preference for ECMO if he deteriorates

Vignette 5: Child with complex congenital heart disease

Part 1: You are due to meet the parents of a 3-month-old baby girl currently on ECMO. Her background includes:

 Antenatal diagnosis of hypoplastic left heart syndrome

 IVF conception after 7 years of attempts

 Underwent Norwood stage 1 procedure at 2 days of age. On return to PICU, she had a rising lactate and escalating inotropes, prompting cannulation for ECMO at 8 h post-operatively

 Required 5 days of ECMO support before decannulation

 Two-month admission in PICU before being transferred to the cardiology ward

 Most recent echocardiogram demonstrated moderately reduced ventricular function with moderate tricuspid valve regurgitation. Two days ago, she had progressive desaturation with a cardiac arrest, and was cannulated onto ECMO after 25 min of CPR

 Part 2: Her parents have seen on multiple parent blogs about the role of long-term ventricular assist device (VAD) support and transplantation and would like to document their preference for these interventions