The Economic Implications of Introducing Single-Patient ECG Systems for Cardiac Surgery in Australia

Figures & data

Figure 1 Literature review screening flow-chart.

Abbreviations: CABG, Coronary Artery Bypass Graft; SSI, Surgical Site Infection.

Figure 2 Model overview.

Abbreviations: CABG, Coronary Artery Bypass Graft; ICU, Intensive Care Unit; MV, Mechanical Ventilation; GW, General Ward; SWI, Sternal Wound Infection.

Table 1 Base-Case Parameters

Input	Value	Variance	Source
Population Characteristics
Age, years (range)	68 (58–73)	2.30	[^Citation13,Citation23]
Gender, % female	24.8	0.30	[^Citation23]
Obese patients, %	32.7	0.33	[^Citation23]
Morbidly obese patients, %	3.27	0.12	Assumption that 1 in 10 obese patients is morbidly obese
Diabetes, %	29	0.32	[^Citation23]
Clinical Setting
Annual CABG procedures in Australia, N	8952		[^Citation9^–^Citation11]
Time on MV, days (range)	0.5 (0.5–30)		[^Citation29]
Time in ICU, days (range)	1.53 (0.5–30)		[^Citation30]
Hospital time, days (range)	8.4 (5.2–13.8)	1.79	[^Citation31]
LoS SSI, days	7.46	3.73	[^Citation30]
LoS DSWI, days	16	8.0	[^Citation27]
Prolonged MV patients, % (range)	5.3 (3.8–9.5)		[^Citation32]
ECG monitoring, days (range)	6 (5.2–13.8)	1.79	[^Citation31]
Discharge home, %	74.5	0.17	[^Citation33]
Facility stay, days (range)	27 (10.6–62.7)	11.91	[^Citation34]
30 days in-hospital mortality, % (range)	0.4 (0–1.6)	0.3	[^Citation23]
30 days SSIs (% of which DSWIs)	3.6 (36.1)		[^Citation13]
False alarms, N per 100 patient days	57	1.43	[^Citation15]
Leads-off alarms, N per 100 patient days	40.9	4.92	[^Citation15]
Relative Risk of Events
LoS ICU, morbidly obese, RR (range)	4 (1.6–22.4)	5.10	[^Citation25]
DSWI, morbidly obese, RR (range)	13.1 (2.4–51.7)		[^Citation24]
DSWI, diabetic, RR (range)	1.6 (0.2–3.1)	0.20	[^Citation26]
Prolonged MV, morbidly obese, RR (range)	1.73 (1.25–2.29)	0.10	[^Citation25]
Hospital mortality, morbidly obese, RR (range)	1.64 (0.99–2.51)	0.18	[^Citation25]
spECG SSI, OR (range)	0.74 (0.56–0.95)	0.09	[^Citation16,Citation22]
spECG false alarms, RR (range)	0.81 (0.55–1.14)	0.13	[^Citation15]
spECG leads-off alarm, RR (range)	0.71 (0.46–1.03)	0.15	[^Citation15]
Costs (AUD 2019)
rECG cost per patient use	9.4		Calculated value based on^Citation35 and assumptions^†
spECG cost per patient use	20		Data on file, Cardinal Health
CABG	14,665	1466	[^Citation36]
Mechanical ventilation	2433	248	[^Citation37]
ICU per day	4875	885	[^Citation38]
General ward per day	2104	210	[^Citation36]
Nurse time, per hour	55	5.58	[^Citation39]
Inpatient SSI	66	25	[^Citation30]
Outpatient care for SSI	924	47	[^Citation40]
Inpatient DSWI	66	25	[^Citation30]
Readmission for DSWI	19,943	2035	[^Citation41]
False alarm, care minutes per event	2		Estimate of acknowledged contributor, Prof. RZS^¥
Leads-off alarm, care minutes per event	1

Notes: ^†Lead and cable cost from MedShop³⁵ (Welch Allyn 10-lead replaceable lead set CP100/CP200 and digital ECG Patient cable, 10-lead with replaceable leads AHA CP). Accessed Jan 9, 2019. Assumed use: 1-year, average wear time 6 days, 1-day turn-around: 52 patient uses. ^¥Professor Ramon Z. Shaban, Chair of infection prevention and disease control at the University of Sydney and Western Sydney Local Health District.

Abbreviations: CABG, Coronary Artery Bypass Graft; DSWI, Deep Sternal Wound Infection; ECG, Electrocardiograph; ICU, Intensive Care Unit; LoS, Length of Stay; MV, Mechanical Ventilation; OR, Odds Ratio; RR, Relative Risk; rECG, reusable Electrocardiograph; spECG, single-patient Electrocardiograph; SSI, Surgical Site Infection.

Table 2 Base Case Results, ICU Days, GW Days and Readmissions, spECG versus rECG

	ICU days	GW days	Readmissions	Total Cost (AUD 2019)
spECG	14,921	77,047	138	334,094,155
rECG	15,024	77,611	186	336,548,332
Difference	−103	−565	−48	−2,454,177

Abbreviations: AUD, Australian Dollars; GW, General Ward; ICU, Intensive Care Unit; rECG, reusable Electrocardiograph; spECG, single-patient Electrocardiograph.

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