Table 1

Summary of key components of process evaluation highlighted by each study conducted by the authors

	Qualitative study of critical illness survivors 200912	Telephone CST 20129	Telephone mindfulness training RCT 20148	Telephone and web-based CST vs education control RCT 20187	Mobile mindfulness vs telephone mindfulness vs education control RCT 20185
Implementation
‘What’	N/A	CST	Mindfulness training	CST vs education control	Mindfulness training vs education control
‘How’		Telephone delivery: acceptable and feasible	Telephone delivery: acceptable and feasible	Telephone and web-based	Telephone vs mobile App
Dose		6 weekly sessions	6 weekly sessions	6 weekly sessions	4 weekly sessions
Interventionist		Critical care nurse	Clinical psychologist and MD	Clinical psychologist	Clinical psychologist
Fidelity Monitoring		Not described	Not described	Not described	Audio recording (telephone) and technology-based tracking (App)
Adherence/ Uptake:		7/10 enrolled patients completed all study procedures 7/7 starting intervention completed it	6/11 patients enrolled completed all study procedures	62/86 (72%) and 69/89 (78%) patients randomised to CST and education control, respectively, completed all study procedures	22/31 (71%), 28/31 (90%) & 16/18 (89%) randomised to mobile mindfulness, telephone mindfulness and education control completed all study procedures, respectively
		92% (77/84) possible sessions completed	Proportion of sessions completed not reported	54/86 (63%) and 58/89 (65%) of CST and education control patients, respectively, completed ≥1 session	93/96 (97%) possible weekly app sessions were completed
		92% (77/84) possible sessions completed	Proportion of sessions completed not reported	Most common reason for low adherence was ‘medical illness’. Loss to follow-up associated with low education and family support; greater financial stress & baseline psychological distress; discharge to inpatient rehabilitation or skilled nursing facility	Self-paced might have improved adherence to App
Other		Able to incorporate caregivers	Opportunity to improve access to intervention (perhaps using technology)		Patients requested more interactive features and enhanced visualisation of progress over time
Mechanisms of impact	N/A	Unclear if there is a differential response based on baseline symptoms and coping skills	Increases in mindfulness qualities were associated with improvements in psychological distress	Greater improvement in self-efficacy among those with higher baseline HADS scores	Increased frequency, duration and quality of App use associated with greater decrease in depression symptoms
Context	ICU survivors commonly experience psychological distress Few evidence-based interventions to improve psychological distress in ICU survivors	Ineffective coping is associated with increased psychological stress	Mindfulness training, a behavioural intervention, is beneficial in improving psychological distress in other populations	Web-based content might enhance the effects of telephone-delivered CST Patients with high baseline distress might be the most likely to benefit	There are potential barriers to delivering an intervention by phone. A mobile App might overcome such barriers

App, application; CST, coping skills training; HADS, Hospital Anxiety and Depression Scale; ICU, intensive care unit; MD, doctor of medicine; N/A, not applicable; RCT, randomised controlled trial.