Keywords
Endoscopy Upper GI Tract - Diagnosis and imaging (LCI, BLI, NBI) - Endoscopy Lower
GI Tract - Small bowel endoscopy
Introduction
The average global temperature rose above 1.45°C in 2023, reaching a new record high.
Climate change poses serious threats to human health and life [1]. Greenhouse gases (GHG) are major contributors to climate change.
In the medical field, GHG emissions account for 4.6% of the world’s total, and their
impact on global warming has been widely recognized. In hospital environments, the
main departments that emit GHG are operating theaters, intensive care units, and endoscopy
suites, which are also among the top three departments generating the most harmful
medical waste [2].
Endoscopy-related academic societies have emphasized the importance of initiatives
to reduce the environmental impact of endoscopy and have proposed specific measures
to achieve this goal [3]
[4]
[5].
In addition to waste associated with endoscopy, the power consumption involved is
also a crucial factor in reducing GHG emissions. Gayam [6] analyzed power consumption of endoscopy-related units and found that the endoscope
system accounted for a large proportion of the total power consumption, along with
that of the washing machines.
Fujifilm Corporation (Tokyo, Japan) developed a new endoscope system that uses a light-emitting
diode (LED) light source instead of a xenon (Xe) light source. An endoscope system
(ELUXEO) with four LEDs has been marketed in the West since 2017 and in Japan since
2020 [7]
[8]. This system has the advantage of consuming less power than a conventional endoscope
system with the Xe light source. Furthermore, LED light sources are considerably more
durable than Xe ones.
In this study, we estimated the reduction effect of GHG emissions using an LED-based
endoscope system compared with a conventional endoscope system using a Xe light source.
Methods
To calculate power consumption during endoscopic procedures, data were collected on
the operating time of endoscope systems conducted at Jichi Medical University Hospital.
The endoscopic procedures included in this study are esophagogastroduodenoscopy (EGD),
colonoscopy (CS), endoscopic retrograde cholangiopancreatography (ERCP), endoscopic
submucosal dissection (ESD), and double-balloon enteroscopy (DBE). EGD, CS, and ERCP
are routinely performed and a large number of the procedures are performed daily.
As a result, an endoscope system remains operational during patient transitions between
examinations. In practice, during a procedure, a processor, a light source, and an
air/water pump are turned on, whereas during patient transitions, the light source
and the air/water pump are turned off. Therefore, both the procedure and standby time
during patient transitions were collected. For ESD and DBE, the endoscope system is
operated only during each procedure; therefore, only the procedure time was collected.
Power consumption specific to endoscope systems was calculated using the design values
for the ELUXEO system with the LED light source and an endoscope system with the Xe
light source (Advancia, Fujifilm, Tokyo, Japan) under operating conditions during
both procedure and standby times. Power consumption used by the endoscope system was
calculated as the product of its power consumption rate and the corresponding operating
time. Therefore, power consumption per procedure for EGS, CS, and ERCP was calculated
as the sum of the power consumption during the procedure and standby times. For ESD
and DBE, power consumption per procedure was calculated based only on procedure time.
Annual power consumption was calculated by multiplying power consumption per procedure
by the annual number of procedures.
An outcome of this study was to compare power consumption of the endoscope system
using a Xe light source with that using an LED light source under actual clinical
conditions.
Power consumption data per procedure and annual power consumption data were analyzed
using the average and 95% confidence intervals (CIs). A comparison of power consumption
between the Xe endoscope system and the LED endoscope system was evaluated based on
these averages and 95% CIs. A sensitivity analysis also was included in the comparison.
Power consumption was converted to CO2 emissions, using a conversion factor of 0.47 (kg- CO2/kWh) based on the figure published by the Ministry of Economy, Trade and Industry
in 2024 [9].
The reduction effect on a national basis also was estimated. This estimation was performed
by multiplying average power consumption per procedure by the number of procedures,
which was taken from a Japanese procedure database [10].
This study was exempt from ethical approval according to the Japanese Ethical Guidelines
for Medical and Biological Research Involving Human Subjects [11].
Results
Operating time data for EGD, CS, and ERCP were prospectively collected between December
16, 2024 and December 24, 2024. Operating time data for ESD for early gastric cancer
were collected from procedures conducted in 2023, those of ESD for colorectal neoplasia
were collected in 2024, and those of DBE were collected in 2022, all of which were
stored in a clinical database at Jichi Medical University Hospital. Data for which
accurate examination times were registered were selected. The number of examinations
in each category during the 3 years were similar.
Data used for analysis included 119, 53, and 14 consecutive cases of EGD, CS, and
ERCP, respectively. ESD for early gastric cancer and DBE datasets comprised 214 and
538 consecutive cases, respectively. For ESD of colorectal neoplasia, 24 cases were
analyzed, with one case extracted from every four consecutive procedures.
DBE, ESD, and ERCP were all performed under sedation. EGD and CS were mostly performed
without sedation.
[Table 1] presents power consumption values specific to both endoscope systems. The LED endoscope
system reduced power consumption during the procedure by 38% compared with the Xe
endoscope system.
Table 1 Power consumption of endoscope systems.
|
Endoscope system
|
Power consumption during procedure (W)
|
Power consumption during standby (W)
|
|
Advancia (Xe) the endoscope system with the xenon lamp; ELUXEO (LED), the endoscope
system with the light-emitting diode.
During the procedure, a processor, a light source, and an air/water pump are
turned on. During standby, associated with changing patients, a light source and the
air/water pump are turned off.
|
|
Advancia (Xe)
|
374.8
|
57.4
|
|
ELUXEO (LED)
|
141.4
|
80.6
|
[Table 2] shows operating time and power consumption per procedure. Operating time for EGD,
CS, and ERCP includes standby time associated with changing transitions. Standby times
for EGD, CS, and ERCP were fixed values corresponding to the average of the collected
data: 11.7, 15.4, and 27.4 minutes, respectively. Power consumption per procedure
was calculated as the product of procedure time and power consumption value of the
endoscope systems listed in [Table 1].
Table 2 Operating time and power consumption per procedure.
|
Procedure items
|
Average operating time (min)
|
Power consumption (Wh)
|
|
Mean
|
95% CI
|
Xe
|
LED
|
|
Mean
|
95% CI
|
Mean
|
95% CI
|
|
CI, confidence interval; CS, colonoscopy; DBE, double-balloon enteroscopy; EGD, esophagogastroduodenoscopy;
ERCP, endoscopic retrograde cholangiopancreatography; ESD, endoscopic submucosal dissection;
LED, light-emitting diode endoscope system; Xe, xenon endoscope system.
The formula for calculating power consumption is as follows:
*Power consumption per procedure (Wh) = {procedure time (min) x power consumption during
procedure (W) + standby time (min) x power consumption during standby (W)}/60.
†Power consumption per procedure (Wh) = {procedure time (min) x power consumption during
procedure (W)}/60.
|
|
EGD*
|
18.9
|
18.3–19.4
|
54.4
|
51.1–57.9
|
32.4
|
31.2–33.8
|
|
CS*
|
38.8
|
35.8–42.0
|
156.2
|
138.8–175.8
|
75.1
|
68.3–82.6
|
|
ERCP*
|
55.7
|
47.3–65.5
|
193.4
|
145.6–257.0
|
102.1
|
83.1–125.4
|
|
ESD for early gastric cancer†
|
79.8
|
74.0–86.0
|
498.3
|
462.1–537.4
|
188
|
174.3–201.7
|
|
ESD for colorectal neoplasia†
|
116.2
|
88.4–152.6
|
725.8
|
552.4–953.5
|
273.8
|
208.4–359.7
|
|
DBE†
|
57.8
|
55.4–60.3
|
360.8
|
345.9–376.4
|
136.1
|
130.5–142.0
|
Because data for operating time and power consumption for each procedure showed a
log-normal distribution trend, log-transformed data were used to calculate the mean
and 95% CIs. Results are presented as geometric means and corresponding 95% CIs.
For all procedure types, power consumption per procedure using the LED endoscope system
was significantly lower than that for the Xe endoscope system. The upper limit of
the 95% CIs for the LED endoscope system was lower than the lower limit of those for
the Xe endoscope system, indicating a statistically significant difference.
[Table 3] presents annual power consumption based on annual number of procedures at Jichi
Medical University Hospital. Power consumption was calculated by assuming that all
procedures were performed using either the Xe or LED endoscope systems. Average total
power consumption of the LED endoscope system was 49% of that of the Xe endoscope
system.
Table 3 Annual power consumption at Jichi Medical University Hospital.
|
Procedure items
|
Number of annual procedures (FY2022)
|
Annual power consumption (kWh)*
|
|
Xe
|
LED
|
|
|
Mean
|
95% CI
|
Mean
|
95% CI
|
|
CS, colonoscopy; DBE, double-balloon enteroscopy; EGD, esophagogastroduodenoscopy;
ERCP, endoscopic retrograde cholangiopancreatography; ESD, endoscopic submucosal dissection;
FY, fiscal year; LED, light-emitting diode endoscope system; Xe, xenon endoscope system.
The formula for calculating annual power consumption is as follows:
*Annual power consumption (kWh) = {Power consumption per procedure (Wh) x Number of
annual procedures}/1000.
|
|
EGD
|
7,151
|
388.7
|
365.1–413.8
|
231.9
|
222.9–241.4
|
|
CS
|
4,437
|
693.1
|
615.9–779.9
|
333.3
|
303.1–366.5
|
|
ERCP
|
724
|
140.1
|
105.4–186.1
|
73.9
|
60.2–90.9
|
|
ESD for early gastric cancer
|
281
|
140
|
129.9–151.9
|
52.8
|
49.0–57.0
|
|
ESD for colorectal neoplasia
|
105
|
76.2
|
58.0–100.1
|
28.8
|
21.9–37.8
|
|
DBE
|
540
|
194.8
|
186.8–203.2
|
73.5
|
70.5–76.7
|
|
Total
|
13,238
|
1632.9
|
-
|
794.2
|
-
|
[Table 4] summarizes annual power consumption reduction between the Xe and LED endoscope systems.
The reduction is presented as a base-case scenario for the difference in average values,
as the best-case scenario for the difference in the upper limit of the 95% CIs, and
as the worst-case scenario for the difference in the lower limit of the 95% CIs. In
the base-case scenario, 838.7 kWh of power was saved, equivalent to 394.2 kg of CO2 emissions.
Table 4 Annual power reduction at Jichi Medical University Hospital.
|
Procedure items
|
Annual power reduction (kWh)
|
|
|
Base*
|
Best†
|
Worst‡
|
|
EGD, esophagogastroduodenoscopy; CS, colonoscopy; ERCP, endoscopic retrograde cholangiopancreatography;
ESD, endoscopic submucosal dissection; DBE, double-balloon enteroscopy.
The formula for calculating annual power reduction is as follows:
*Difference in average values between the Xe and LED endoscope systems.
†Difference in upper limits of the 95% confidence intervals between the Xe and LED
endoscope systems.
‡Difference in lower limits of the 95% confidence intervals between the Xe and LED
endoscope systems.
|
|
EGD
|
156.8
|
172.4
|
142.2
|
|
CS
|
359.8
|
413.4
|
312.8
|
|
ERCP
|
66.2
|
95.2
|
45.2
|
|
ESD for early gastric cancer
|
87.2
|
94.9
|
80.9
|
|
ESD for colorectal neoplasia
|
47.4
|
62.3
|
36.1
|
|
DBE
|
121.3
|
126.5
|
116.3
|
|
Total
|
838.7
|
964.7
|
733.5
|
The estimated reduction effect on a domestic basis was calculated using the average
power consumption per procedure at Jichi Medical University Hospital and the number
of domestic procedures reported in Japan’s National Database (NDB) for the fiscal
year 2022 [10], focusing on endoscopies with a high number of procedures, such as EGD, CS, and
ESD. Assuming all endoscopic procedures were performed using the LED endoscope system,
total power consumption would be reduced to 53% of that with the Xe endoscope system,
resulting in a power savings of 428,628.8 kWh ([Table 5]). That amount of power saved was equivalent to 201,455.5 kg of CO2 emissions, comparable to driving 513,018 miles using an average gasoline-powered
passenger vehicle [12]. Differences in power consumption reduction rates between Jichi Medical University
Hospital and the domestic basis are due to differences in procedure items evaluated.
Table 5 Annual power consumption and power reduction in Japan.
|
Procedure items
|
Number of annual procedures (FY2022)
|
Annual power consumption (kWh)*
|
Annual power reduction (kWh)†
|
|
Xe
|
LED
|
|
CS, colonoscopy; EGD, esophagogastroduodenoscopy; ESD, endoscopic submucosal dissection;
FY, fiscal year; LED, light-emitting diode endoscope system; Xe, xenon endoscope system.
The formula for calculating annual power consumption and reduction is as follows:
*Annual power consumption (kWh) = {Power consumption per procedure (Wh) x Number of
annual procedures}/1000.
†Annual power reduction (kWh) = (Annual power consumption of the Xe endoscope system)
- (Annual power consumption of the LED endoscope system).
|
|
EGD
|
7,877,146
|
428,516.7
|
255,219.5
|
173,297.2
|
|
CS
|
2,793,712
|
436,377.8
|
209,807.8
|
226,570.0
|
|
ESD for early gastric cancer
|
49,399
|
24,615.5
|
9,287.0
|
15,328.5
|
|
ESD for colorectal neoplasia
|
29,719
|
21,570.1
|
8,137.1
|
13,433.0
|
|
Total
|
10,749,976
|
911,080.1
|
482,451.4
|
428,628.8
|
Discussion
The effect of the LED endoscope system in reducing CO2 emissions has been demonstrated using data from real-world endoscopic procedures.
The results showed that the amount of power consumed by the LED endoscope system at
Jichi Medical University Hospital was almost half that of the Xe endoscope system,
indicating a significant reduction in CO2 emissions. This provides the first evidence supporting the superiority of LED systems,
as described in the position statement by the European Society of Gastrointestinal
Endoscopy and the European Society of Gastroenterology and Endoscopy Nurses and Associates
[3].
Several studies have reported on the environmental impact of endoscopic devices [6], washing machines [6], and histopathological diagnoses [13] related to endoscopic procedures. This study analyzed the effect of reducing CO2 emissions using an endoscope system with an improved light source.
Reports have also highlighted the impact of avoiding unnecessary procedures on the
environmental burden based on accurate diagnosis. Yusuf et al. estimated reductions
in GHG emissions by evaluating the number of medical procedures avoided during CS
screening [14]. Cho et al. estimated reduction in CO2 emissions and medical costs resulting from the high diagnostic performance of narrowband
imaging observation in diagnosing gastrointestinal epithelial hyperplasia [15]. Ueda et al. proposed a strategy for reducing GHG emissions and maintaining high-quality
patient care by reducing unnecessary surveillance endoscopy and biopsy through adoption
of accurate methods for endoscopic diagnosis, such as image-enhanced endoscopy (IEE)
and artificial intelligence [16].
The LED endoscope system was equipped with IEE functions for blue light imaging (BLI)
and linked color imaging (LCI). Reports have shown that BLI and LCI have significantly
higher detection and differentiation capabilities for upper gastrointestinal tumors
and colorectal neoplasms than white light imaging [15]
[16]
[17]
[18]
[19]. Similar findings were reported in other countries such as China and Brazil [20]
[21]. These capabilities facilitate targeted rather than random biopsies, thus contributing
to a reduction in the number of biopsy samples.
By adopting the LED endoscope system, we can expect to reduce power consumption, thereby
decreasing environmental burden owing to improvement in diagnostic performance.
In this study, we investigated power consumption of endoscope systems used in real
clinical settings at a hospital. The investigation did not include consideration of
the supply chain associated with product manufacturing. The two types of endoscope
systems examined in this study differ only in their light source units for illumination.
The environmental impact of the endoscope systems, excluding the light source units,
is considered equivalent throughout their entire lifecycle.
In clinical hospital environments, in addition to power consumption, replacement and
disposal of light source units due to their lifespan also pose challenges. Regarding
the lifespan of light source units, the LED light source is superior to the Xe light
source in terms of its lifecycle. The LED light source has a lifespan equivalent to
that of the endoscope system, whereas the Xe light source has a lifespan of 500 hours
[22]
[23]. However, the environmental impact associated with replacement and disposal of Xe
light sources due to their short life span accounts for only a small percentage of
annual power consumption under the usage conditions at Jichi Medical University Hospital.
Therefore, this study only considered power consumption as the measurement target.
This study has limitations. The reduction effect on a domestic basis was an approximate
prediction result extrapolated using the conditions of the endoscopy suites at a single
university hospital. Another limitation is that power consumption of Olympus endoscope
systems has not been evaluated.
Conclusions
In conclusion, the effect of reducing CO2 emissions using the LED endoscope system has been demonstrated. Wider adoption of
the LED endoscope system will contribute to usefulness of endoscopic diagnosis and
reduce the environmental impact.
Bibliographical Record
Katsuya Kikuchi, Tomonori Yano, Yoshikazu Hayashi, Yuji Ino, Takashi Ueno, Satoshi
Ozawa, Kentaro Sugano. Reduction of greenhouse gas emissions using the endoscope with
a light-emitting diode light source. Endosc Int Open 2025; 13: a27339780.
DOI: 10.1055/a-2733-9780
