Economic evaluation of a vision-based patient monitoring and management system in addition to standard care for adults admitted to psychiatric intensive care units in England

Figures & data

Table 1. Clinical inputs used to scale populations.

Parameter	Clinical study specific input	Average sized ward input	NHS input	Source/comment
Average length of stay per patient (days)	48	48	48	Average length of stay for adult mental illness^6.
Number of wards	1	1	N/A	Clinical study specific input^4. Additional information provided by Oxehealth. Average sized ward and NHS input^7
Average beds per ward	11	12	12
Average occupancy	91%	90%	90%
Total occupied bed days per year	3,648	3,945	302,427	Assumed 365.25 days in a year to calculate this figure. 5% of NHS England mental health hospital beds are assumed to be in PICUs.

Figure 1. Model structure.

Table 2. Clinical inputs used in the model.

Parameter	Reported value (95% confidence interval)	Source/comment
Night-time observation hours
Number of night-time observations per occupied bed day	28.8	Unpublished NHS observational study^4. Additional  information provided by Oxehealth.
Night-time observation time per patient (seconds)	23
Reduction in observation time from VBPMM	41% (25–53%)
One to one observation hours
Number of one to one observation hours per occupied bed day	7.39	Unpublished NHS observational study^4. Additional  information provided by Oxehealth.
Reduction in one to one observation hours from VBPMM	7% (–41%)
Proportion of one to one observation hours that is cash releasing	78%
Assaults
Average number of assaults per occupied bed day	0.0125	Unpublished NHS observational study^4. Additional  information provided by Oxehealth.
Reduction in assaults from VBPMM	26% (–18%)
Staff hours per incident	7.3	See Supplementary Appendix 2 for more details.
Proportion visiting A&E	2%	Unpublished NHS observational study^4. Additional information provided by Oxehealth.
Rapid tranquillization events
Average number of rapid tranquillization events per occupied bed day	0.0253	Unpublished NHS observational study^4. Additional  information provided by Oxehealth.
Reduction in rapid tranquillization events from VBPMM	40% (10%)
Staff hours per incident	10.1	See Supplementary Appendix 2 for more details.
Complication risk from using tranquillizers	3%	Proxy taken based on proportion of people that suffer cardiovascular complications^14.

The analysis on the data was conducted at two separate timepoints, meaning most confidence intervals were estimated using one-tailed t-tests, rather than a two-tailed test. Table 4 provides a more detailed explanation of why this is the case.

Table 3. Costs associated with PICU events and VBPMM.

Parameter	Value	Source/comment
Night-time observation hours
Weighted staff cost for observation time per hour	£30	Hospital based nurses. Assumed 70% band 3 nurse (HCA), 30% band 5 nurse. HCA inflated from 2017 as unavailable in more recent PSSRU^11^,^12
One to one observation hours
Weighted staff cost for observation time per hour	£30	Hospital based nurses. Assumed 70% band 3 nurse (HCA), 30% band 5 nurse. HCA inflated from 2017 as unavailable in more recent PSSRU^11^,^12
Assaults
Weighted staff cost per hour	£45	Hospital based staff. Psychiatric consultant, band 7 nurse, band 5 nurse. Band 3 nurse (HCA)^11^,^12. See Supplementary Appendix 2 for more details.
Cost of A&E (non-surgery)	£2,134	Weighted average of fractures codes (HE71B-HE11H) without interventions.^15
Rapid tranquillization event
Weighted staff cost per hour	£43	Hospital based staff. Psychiatric consultant, band 7 nurse, band 5 nurse. Band 3 nurse (HCA)^11^,^12. See Supplementary Appendix 2 for more details.
Cost of tranquillizers	£5	Haloperidol (5 ml) intramuscular injection (Alliance Healthcare Distribution) 1 unit^16. Promethazine hydrochloride, intramuscular injection (Phenergan) 2 units^17^,^18.
Cost of tranquillizer complication	£716	Weighted average of angina codes (EB13A-EB13D)^15.
VBPMM
Cost of VBPMM (average sized ward)	£26,190	Annual license fees, installation cost and cabling costs were provided by Oxehealth. Staff training costs were calculated by combining staff costs from PSSRU with estimated staff numbers requiring training per ward provided by Oxehealth^9^,^10.

Table 4. Confidence intervals.

Parameter	Base case	Lower bound	Upper bound
Reduction in night-time observation time from VBPMM	41%	25%	53%
Reduction in one to one observation hours from VBPMM	7%	–41%	–
Reduction in assaults from VBPMM	26%	–18%	–
Reduction in rapid tranquillization events from VBPMM	40%	10%	–

The analysis on the data was conducted at two separate timepoints. Initially, the analysis used a linear approach to significance testing given there was no previously reported standard. Analysis on night-time observation was conducted at a later date and used a log approach to align with standards recommended by Cochrane’s updated guidance on significance testing [19].

Table 5. Summary results.

	Standard care	VBPMM + standard care	Difference
Cost of night-time observational hours	£268	£158	–£109
Cost of one to one observation hours	£10,749	£9,943	–£806
Cost of assaults	£227	£167	–£60
Cost of rapid tranquillization event	£562	£338	–£223
Cost of VBPMM	£0	£319	£319
Total cost per patient	£11,806	£10,926	–£880
Total cost per occupied bed day	£246	£228	–£18
Total cost per average sized ward per year	£970,193	£897,907	–£72,286
Total cost to the NHS per year	£74,381,491	£68,839,567	–£5,541,924

Figures are rounded to the nearest integer.

Table 6. Scenario with only significant events.

	Standard care	VBPMM + standard care	Difference
Total cost per occupied bed day	£246	£246	£0
Total cost per patient	£11,806	£11,792	–£14
Total cost per average sized ward per year	£970,193	£969,053	–£1,140
Total cost to the NHS per year	£74,381,491	£74,294,073	–£87,418

Figures are rounded to the nearest integer.

Figure 2. Tornado plot.

Hospital Episodes Statistics. Hospital admitted patient care activity 2019-20; 2020 [cited 2021 Feb 8]. Available from: https://digital.nhs.uk/data-and-information/publications/statistical/hospital-admitted-patient-care-activity/2019-20

 Google Scholar

Coventry and Warwickshire Partnership NHS Trust. How technology can change services; 2020 [cited 2021 Mar]. Available from: https://assets-global.website-files.com/5f567869171c90518f161723/5f7e0bad1a06a32e1da2a3ab_qnpicu–-webinar-presentation-flyer–17-july-2020.pdf

 Google Scholar

The Strategy Unit NHS. Exploring mental health inpatient capacity across sustainability and transformation partnerships in England; 2019 [cited 2021 Mar]. Available from: https://www.strategyunitwm.nhs.uk/sites/default/files/2019-11/Exploring%20Mental%20Health%20Inpatient%20Capacity%20accross%20Sustainability%20and%20Transformation%20Partnerships%20in%20England%20-%20191030_1.pdf

 Google Scholar

Pilowsky LS, Ring H, Shine PJ, et al. Rapid tranquillisation: a survey of emergency prescribing in a general psychiatric hospital. Br J Psychiatry. 1992;160(6):831-835.

 Google Scholar

Personal Social Services Research Unit (PSSRU). Unit Costs of Health & Social Care 2020. Canterbury: University of Kent; 2020 [cited 2021 Mar]. Available from: https://www.pssru.ac.uk/project-pages/unit-costs/unit-costs-2020/

 Google Scholar

Personal Social Services Research Unit (PSSRU). Unit Costs of Health & Social Care 2017. Canterbury: University of Kent; 2017 [cited 2021 Mar]. Available from: https://www.pssru.ac.uk/project-pages/unit-costs/unit-costs-2017/

 Google Scholar

NHS England. National Schedule of NHS costs 2018/19; 2020 [cited 2021 Mar]. Available from: https://www.england.nhs.uk/national-cost-collection/#ncc1819

 Google Scholar

British National Formulary. Haloperidol: BNF; 2021 [cited 2021 Mar]. Available from: https://bnf.nice.org.uk/medicinal-forms/haloperidol-decanoate.html

 Google Scholar

British National Formulary. Promethazine hydrochloride: BNF; 2021 [cited 2021 Mar]. Available from: https://bnf.nice.org.uk/medicinal-forms/promethazine-hydrochloride.html

 Google Scholar

NHS Sussex Partnership. The Rapid Tranquillisation Policy (including the use of oral PRN medication); 2019 [cited 2021 Mar]. Available from: https://www.sussexpartnership.nhs.uk/sites/default/files/documents/rt_-_rapid_tranquilization_-_jan_2019_ratified_final_circulated.pdf

 Google Scholar

Oxehealth. Patient experience with Oxevision; 2022 [cited 2022 Jun]. Available from: https://assets-global.website-files.com/5f567869171c90518f161723/624af4d6379d9a1d18fdbf85_PER_UK_D_8.1.pdf

 Google Scholar

National Institute of Health and Care Excellence. Guide to the methods of technology appraisal 2013: the reference case; 2013 [cited 2021 Mar]. Available from: https://www.nice.org.uk/process/pmg9/resources/guide-to-the-methods-of-technology-appraisal-2013-pdf-2007975843781

 Google Scholar

Higgins JP, Li T, Deeks JJ. Choosing effect measures and computing estimates of effect; 2021 [cited 2021]. Available from: https://training.cochrane.org/handbook/current/chapter-06

 Google Scholar

Data availability statement

To request the original data regarding Oxevision please contact [email protected]