Study

Study characteristics

Patient characteristics

Measurement instrument (I)

Measurement instrument (C; golden standard; reference method)

Follow-up/Interpretability

Measurement properties

Comments

Eley, 2021

Instrument assessed:

Continuous  non-invasive blood pressure via finger cuff

Setting and Country:

The royal Brisbane and Women’s Hospital, Brisbane, Australia

Funding and conflicts of interest:

Funding: ANZCA Research Foundation, Australian and New Zealand Colelge of Anaesthetists, Melbourne, Australia; Robert and Janelle Bird Post-Doctoral Fellowship awared by the Royal Brisbane and Women\s Hospital Foundation, Brisbane, Australia;
Conflicts of interests:
Edwarts Lifesciences Corp, Irvane, CA provided loadn equipment for the study, but was not involved in the protocol design, data collection or writing the manuscript.

Inclusion criteria:

• ≥ 18 years old
• BMI ≥ 45 kg/m²
• Scheduled for elective laparoscopic bariatric surgery

Exclusion criteria:

• Cardiac arrhythmia
• American Society of Anesthesiologists physical status ≥ 4
• Raynoud’s phenomenon
• Other contraindications to radial arterial catherisation

Sample size:

N=67
(30 included in the final protocol)

Age in years (mean (SD; range)):

45 (11.7; 24 to 65)

Gender (% female):
male: 4(13%)
female: 26 (87%)

BMI in kg/m² (medan (IQR; range)):

50.2 (48.3 to 55.3; 45.1 to 69.2)

Disease:

NA

Disease duration (mean (SD) in years:

NA

Disease severity:

NA

Name:

Continuous non-invasive blood pressure measurement using the vascular unloading technique via a finger cuff

Version (including language if applicable):

Clearsight EV1000 Clincal Platform (Edwads Lifesciences Corp, Irvine, CA

Construct:

Non-invasive blood pressure
systolic blood pressure

(SBP), mean arterial pressure (MAP) and diastolic blood pressure (DBP)

Specification of investigated component:

Following standard positioning

of the patient (one pillow under the head, table in the reverse Trendelenburg position) the first blood pressure

measurements were obtained

Specification of time, occasion, user:
Blood pressure was recorded digitally at 5 min intervals for each patient up to 1 hour, or until completion of

anesthesia

Hypothesis (construct validity hypothesis testing):

Not reported

Name:

Radial arterial catheter

Version (including language if applicable):

invasive transducer (Edwards Lifesciences Tru-

Wave™, Edwards Lifesciences Corp, Irvine, CA, USA); D19KT™

monitor with a E-PSMP Carescape Module™ (GE

Healthcare, Chicago, IL, USA).

Construct:

invasive radial arterial blood pressure monitoring

Specification of investigated component:

Following standard positioning

of the patient (one pillow under the head, table in the reverse Trendelenburg position) the first blood pressure

measurements were obtained

Specification of time, occasion, user:

Blood pressure was recorded digitally at 5 min intervals for each patient up to 1 hour, or until completion of

anesthesia

Length of follow-up:

Up to 1 hour, or until completion of anesthesia

Distribution of scores:

I: NR
C: NR

Loss to follow-up:
N=37
Reasons:
research staff unavailable (12);
procedure cancelled (10);
clear sight device unavailable (10);
anesthesis declined (2);
clear sight device failure (2);
unable to insert arterial catheter (1)

Percentage of missing items/total scores/outcome:
All patients had complete blood pressure

measurements up to 15 min, after which the number of

measurements per method ranged between 26 and 30,

due to variations in the duration of surgery

Floor effects (% of sample with the lowest score possible):
I: NR
Reason: NR
C: NR
Reason: NR

Ceiling effects (% of sample with the highest score possible):

I: NR
Reason: NR
C: NR
Reason: NR

Minimally important change/difference:
I:NR
Reason: NR
C: NR
Reason: NR

Criterion validity:

Mean arterial blood pressure, bland altman

bias:
 5.2 mmHG
(SD 10.9) m
lower LOA:
-16.0 mmHG
(95%CI -22.0 to -11.9)

Upper LOA:
26.5 mmHG
(95%CI 22.3 to 32.4) mm

Systolic blood pressure

Bias: 14.3 mmHG
(SD 14.1)
lower LOA:
-13.4 mmHG
(95%CI –20.6 to -8.2)
Upper LOA:
42,0 mmHG (95%CI 36.9 to 49.2)

Diastolic blood pressure

Bias: 2.6 mmHG
(SD 10.8)
lower LOA:
-18.6 mmHG
(95%CI –24.4 to -14.4)
Upper LOA:
23.8 mmHG (95%CI 19.7 to 29.6)

Responsiveness

Disconcordant pairs (n of N (%)):

Mean arterial blood pressure:
15 of 215 (7%)

Systolic blood pressure:

18 of 251 (7%)

Diastolic blood pressure:
16 of 197 (8%)

Clinical impact outcome measures:

Grid analyses (n (%))

The levels are based on whether or not the difference between the readings would trigger a therapeutic intervention and the potential consequences

of that intervention (A: no risk; B: low risk; C: moderate risk;

D: significant risk; E: dangerous risk)

Mean arterial pressure:

Zone A: 338 (91.4%)
Zone B: 16 (4.3%)
Zone C: 16 (4.3%)

Zone D: 0 (0%)

Zone E: 0 (0%)

Systolic blood pressure:

Zone A: 336 (90.8%)
Zone B: 24 (6.5%)
Zone C: 10 (2.7%)

Zone D: 0 (0%)

Zone E: 0 (0%)

Diastolic blood pressure:

NR

Remark: “In 4 (13%) participants

the circumference of the finger was larger than the manufacturer’s

recommendation for the largest finger cuff.”

Author’s conclusion:

“ In this pilot study, the vascular unloading technique did not

provide accurate blood pressure measurements when

assessed over time, with the FC tending to provide lower

values. The clinical consequences of these errors would have led to inappropriate interventions of moderate risk in a small but arguably significant fraction of readings, in this population with a high burden of comorbidities.”

Hager, 2009

Instrument assessed:

Blood pressure via Oscillometric cuff on the upper arm

Setting and Country:

Washington University, St. Louis, MO, USA

Funding and conflicts of interest:

This study was financially supported by the Clinical Research

Division of the Department of Anesthesiology, Washington

University, St. Louis, MO. None of the authors have personal financial

interest related to this research.

Inclusion criteria:

• Body mass index (BMI) exceeding 40 kg/m2
• scheduled for surgery (mainly gastric bypass or repair of gastric bypass)

Exclusion criteria:

• Blood pressure difference between the arms exceeding 5mmHg, determined oscillometrically
• History of Raynaud’s syndrome or other perfunsion difficulties in the arms or hands

Sample size:

22 patients

Age in years (mean (SD):

44.3 (9.5) years

Gender (% female):
NR

BMI  (SD):
66.7 (13.8) kg/m²

Arm Circumference (SD):
48.6 (7.5) cm

Disease:
NA

Disease duration (mean (SD) in years:

NA

Disease severity:

NA

Name:

Oscillometric noninvasive blood pressure upper arm

Version (including language if applicable):

Oscillometric noninvasive blood pressure (Datex-Ohmeda, Madison, WI, USA)

Construct:

systolic, diastolic, and mean blood pressure

Specification of investigated component:

NR

Specification of time, occasion, user:
Blood pressure measurements were taken every 15 minutes.

Hypothesis (construct validity hypothesis testing):

NR

Name:

Invasive arterial blood pressure monitoring

Version (including language if applicable):

The catheters were 20-gauge and 4.45 cm

long (Arrow International, Reading, CA, USA). The pressure

monitoring tubing was 210 cm long; pressure

transducers (both from Edwards Lifescience, Irvine, CA,

USA)

Construct:

systolic, diastolic, and mean blood pressure

Specification of investigated component:

NR

Specification of time, occasion, user:

Blood pressure measurement were collected every 5s.

Length of follow-up:

More than 3 hours (mean 3.8 SD 1.1)

Distribution of scores:

I: NR
C: NR

Loss to follow-up:
I: 3 patients
Reason: NR
C:1 patient
Reason NR

Percentage of missing items/total scores/outcome:
I: mean 3.4% SD 0.6%)
Reason: device errors
C: mean 2.8% SD 1.3%)
Reason: device errors

Floor effects (% of sample with the lowest score possible):
I: NR
Reason:
C: NR
Reason:

Ceiling effects (% of sample with the highest score possible):

I: NR
Reason:
C: NR
Reason:

Minimally important change/difference:
I: NR
Reason:
C: NR
Reason:

Criterion validity:

1) Bland altman analysis (mean bias (lower to upper limit of agreement)

Systolic blood pressure:
-3.6 (-46.7 to 39.6)

Diastolic blood pressure:

-7.6 (-38.1 to 23.0)

Mean arterial blood pressure

1.7 (-28.8 to 32.1)

2) Lin’s concordance correlation coefficient (2.5^th percentile to 97th percentile))

Systolic blood pressure: 0.63 (0.47 to 0.75)

Diastolic blood pressure: 0.47 (0.24 to 0.70)

Mean arterial blood pressure: 0.63 (0.48 to 0.74)

Hansen, 2022

Instrument assessed:

Non invasive blood pressure uisng a forearm cuff

Setting and Country:

Department

of Anaesthesiology and Intensive Care Medicine and

General Surgery, University Medical Center, Schleswig-

Holstein, Campus Kiel, Germany

Funding and conflicts of interest:

Open Access funding enabled and organized by Projekt DEAL; no external funding, only institutional resources

Inclusion criteria:

• Adult
• BMI ≥ 30 kg/m²
• ASA ≥ II
• Indication for elective  laparoscopic bariatric surgery

Exclusion criteria:

• Pre-existing cardiac arrhythmias
• Perifpheral arterial vascular disease
• Fontaine stadium >2
• Pre-existing aortic aneurysm >4.5 cm
• Cognitive or linguistic barriers

Sample size:

N=60 (56 included in final analysis)

Age in years (mean (SD; range)):

46.5 (12.1)

BMI in kg/m² (mean (SD; range)):

49.2 (5.7)

Gender (% female):
male: 27%

Female: 73%

Disease:

NA

Disease duration (mean (SD) in years:

NA

Disease severity:

NA

I1:

Name:

Blood pressure using fingercuff (Nexfin)

Version (including language if applicable):

Nexfin® system (BMEYE,

Amsterdam, The Netherlands, now licensed as Clearsight

® system by Edwards Lifesciences, Irvine, CA, USA)

Construct:

Systolic arterial pressure, Diastolic arterial pressure, Mean arterial pressure

Specification of investigated component:

In the pre-, intra- and postoperative phase, the arterial

pressure was measured at 16 predefined measurement

time points at which hemodynamic changes were likely

expected. (mainly under general anesthesia)

Specification of time, occasion, user:
See specification of investigated component

Hypothesis (construct validity hypothesis testing):

NR

I2:

Name:

Noninvasive blood pressure measurement using forearm cuff (NBP)

Version (including language if applicable):

DURA-CUF™ GE, Boston, MA, USA

Construct:

Systolic arterial pressure, Diastolic arterial pressure, Mean arterial pressure

Specification of investigated component:

In the pre-, intra- and postoperative phase, the arterial

pressure was measured at 16 predefined measurement

time points at which hemodynamic changes were likely

expected. (mainly under general anesthesia)

Specification of time, occasion, user:
See specification of investigated component

Hypothesis (construct validity hypothesis testing):

NR

Name:

Blood pressure using arterial catheter (IAP)

Version (including language if applicable):

Arrow R Intl., Reading, PA,

USA; Transducer: DPT-6000, CODAN pvb Critical Care

GmbH, Forstinning, Germany

Construct:

Systolic arterial pressure, Diastolic arterial pressure, Mean arterial pressure

Specification of investigated component:

In the pre-, intra- and postoperative phase, the arterial

pressure was measured at 16 predefined measurement

time points at which hemodynamic changes were likely

expected. (mainly under general anesthesia)

Specification of time, occasion, user:

See specification of investigated component

Length of follow-up:

Until discharge from PACU

Distribution of scores:

NR

Loss to follow-up:
N=4
Reason: insufficient data acquisition

Percentage of missing items/total scores/outcome:
N=128 (13.4%)
Reasons:
intra-operative events preventing measurements (90);
challenges in function and handling the measurement device (NBP 31, IAP 2, Nexfin 5)

Floor effects (% of sample with the lowest score possible):
I:NR
Reason:
C:NR
Reason:

Ceiling effects (% of sample with the highest score possible):

I:NR
Reason:
C: NR
Reason:

Minimally important change/difference:
I: NR
Reason:
C: NR
Reason:

Criterion validity:

Correlation coefficient:

Lower arm (NBP)

Mean arterial pressure: 0.77

Systolic arterial pressure: 0.63

Diastolic arterial pressure: 0.72

Fingercuff

Mean arterial pressure: 0.88

Systolic arterial pressure: 0.87

Diastolic arterial pressure: 0.80

Bias (bland altman):

Lower arm (NBP)

Mean arterial pressure: 3.94mmHg
Systolic arterial pressure:
3.5mmHg

Diastolic pressure:

4mmHg

Finger cuff

Lower arm (NBP)

Mean arterial pressure: 1.43mmHg
Systolic arterial pressure:
12mmHg

Diastolic pressure:

0.7mmHg

Responsiveness

definition: concordance rate:

lower arm:

Mean arterial pressure: 90%

Systolic arterial pressure: 85%

Diastolic arterial pressure: 89%

Fingercuff:

Mean arterial pressure: 91%

Systolic arterial pressure: 90%

Diastolic arterial pressure: 86%

Author’s conclusions:

In the perioperative management of patients undergoing

laparoscopic bariatric surgery, our study indicates

that NIBP and Nexfin® derived absolute arterial pressure

recordings were not interchangeable with IAP, but

Nexfin® was more precise than NIBP. However, a good

trending ability even under different hemodynamic

stresses was found. Thus, Nexfin® may serve clinically

useful to detect arterial pressure changes and render

perioperative hemodynamic treatment, particularly

in those individuals where NIBP cannot be reliably

established.

Mostafa, 2020

Instrument assessed:

Noninvasive blood pressure cuff

Setting and Country:

University Hospital, Egypt

Funding and conflicts of interest:

None

Inclusion criteria:

• Consecutive adults (≥18 years) with obesity (≥35 kg/m²
• Schedules for bariatric surgery

Exclusion criteria:

• Comorbidities including peripheral vascular diseases, upper extremity operations, upper extremity scars, upper-extremity deep venous thrombosis and arrhythmias
• difference in the preoperative SBP of 10 mmHg or more between the extremities

Sample size:

N=60 (40 included in the protocol)

Age in years (mean (SD; range)):

38 (11)

Gender (% female):
male 5/40 (12.5%)

BMI mean (SD) kg/m²:

46(5)

Disease:

NA

Disease duration (mean (SD) in years:

NA

Disease severity:

NA

Forearm:

Name:

Noninvasive blood pressure cuff forearm

Version (including language if applicable):

adult non-invasive blood pressure cuff (Mindray

Adult NIBP cuff CM1203), sized 25–35 cm

Construct:

Mean arterial pressure, Systolic arterial pressure, Diastolic arterial pressure

Specification of investigated component:

NR

Specification of time, occasion, user:
3 minute interval

Hypothesis (construct validity hypothesis testing):

NR

Upperarm:

Name:

Noninvasive blood pressure cuff upperarm

Version (including language if applicable):

a large adult non-invasive

blood pressure cuff (Mindray Large Adult NIBP cuff CM1204), sized

33–47 cm

Construct:

Mean arterial pressure, Systolic arterial pressure, Diastolic arterial pressure

Specification of investigated component:

NR

Specification of time, occasion, user:

3 minute interval

Hypothesis (construct validity hypothesis testing):

NR

Name:

Radial arterial catheter

Version (including language if applicable):

20-G radial arterial using a Progetti (PG M9500, Italy) monitor.

Construct:

Mean arterial pressure, Systolic arterial pressure, Diastolic arterial pressure

Specification of investigated component:

NA

Specification of time, occasion, user:

3 minute intervals

Length of follow-up:

NR

Distribution of scores:

I:NR
C:NR

Loss to follow-up:
N=20
Reasons: inter-arm difference of more than 10mmHg(16) – exclusion criterium;
failure of arterial catheter insertion (2);
refusal to participate (2)

Percentage of missing items/total scores/outcome:
NR

In the 40 included patients, 262, 259, and 264 pairs of non-invasive readings of blood pressure were obtained from the arm, forearm, and wrist with the corresponding invasive blood pressure readings.

Floor effects (% of sample with the lowest score possible):
I:NR
Reason:
C:NR
Reason:

Ceiling effects (% of sample with the highest score possible):

I:NR
Reason:
C:NR
Reason:

Minimally important change/difference:
I:NR
Reason:
C:NR
Reason:

Criterion validity:

Correlation coefficient (95%CI):

Forearm:

Systolic arterial pressure: 0.71 (0.64 to 0.76)

Diastolic arterial pressure: 0.74 (0.68 to 0.80)

Mean arterial pressure: 0.79 (0.74 to 0.83)

Upper arm:

Systolic arterial pressure: 0.74 (0.68 to 0.79)
Diastolic arterial pressure: 0.67 (0.60 to 0.73)

Mean arterial pressure: 0.79 (0.73 to 0.83)

Mean bias (SD) – bland altman

Forearm:

Systolic arterial pressure: 4.3 (16)

Diastolic arterial pressure: 2.5 (10)

Mean arterial pressure: 6.2 (8.4)

Upper arm:

Systolic arterial pressure: 14.2 (13.6)

Diastolic arterial pressure: 9.9 (10.7)

Mean arterial pressure: 12.8 (9)

Responsiveness:

definition: Correlation coefficient (95%CI)

Forearm:

Systolic arterial pressure: 0.76 (0.69 to 0.80)

Diastolic arterial pressure: 0.74 (0.67 to 0.79)

Mean arterial pressure: 0.74 (0.67 to 0.79)

Upper arm:

Systolic arterial pressure: 0.74 (0.67 to 0.79)

Diastolic arterial pressure: 0.6 (0.5 to 0.68)

Mean arterial pressure: 0.78 (0.72 to 0.89)

Mean bias (SD, 95% limits of agreement)

Forearm:

Systolic arterial pressure: 0.3 ( 10.3, -20 to 20.7)

Diastolic arterial pressure: 0.3 ( 6.3, -12 to 12.7)

Mean arterial pressure: 0.6 ( 12.3, -23.6 to 24.9)

Upper arm:

Systolic arterial pressure: -0.2 ( 9.8, -19 to 19.4)

Diastolic arterial pressure: -0.3 ( 9.1, -18.2 to 17.7)

Mean arterial pressure: 0.4 ( 7.3, -13.9 to 14.8)

Rogge, 2019

Instrument assessed:

Clearsight system

Setting and Country:

Department of Anesthesiology, Center of

Anesthesiology and Intensive Care Medicine, University, Medical Center Hamburg-Eppendorf, Hamburg, Germany

Funding and conflicts of interest:

Funding: Edwards Lifesciences Corp (Irvine, CA)

No conlficts of interest

Inclusion criteria:

• Adult patients
• Severe obesity (<35 kg/m²)
• Scheduled for elective laparascopic bariatric surgery (laparoscopic vertical sleeve gastrectomy or laparoscopic Roux-en-& bypass)
• Continuous arterial pressure monitoring with an arterial catheter was planned independently of the study

Exclusion criteria:

• Systolic arterial pressure difference of ≥10 mmHG in left and right arm measured oscillometrical
• Peripheral vascular disease (Fontaine stadium >2)
• Arterial fibrillation
• Anatomic deformities of the upper extremities
• Peripheral edema

Sample size:

N=35 (included in the final protocol)

Age in years (median (range)):

53 (41-59)

Gender (% female):
male: 25 (71%)
female: 10 (29%)

BMI in kg/m² (median (range))

47 (42-53)

Disease:

NA

Disease duration (mean (SD) in years:

NA

Disease severity:

NA

Name:

Clearsight monitor with an interface cable to the patient monitor

Version (including language if applicable):

Dräger Infinity Delta;

Dräger, Lübeck, Germany

Construct:

Mean arterial pressure, Systolic arterial pressure, Diastolic arterial pressure

Specification of investigated component:

NR

Specification of time, occasion, user:
arterial pressure measurements of the test

and reference method in parallel for about 45 minutes

Hypothesis (construct validity hypothesis testing):

NR

Describe the assessed instrument and used procedures.

Name:

Arterial catheter

Version (including language if applicable):

NR

Construct:

Mean arterial pressure, Systolic arterial pressure, Diastolic arterial pressure

Specification of investigated component:

NR

Specification of time, occasion, user:

arterial pressure measurements of the test

and reference method in parallel for about 45 minutes

Length of follow-up:

45 minutes

Distribution of scores:

I: NR
C: NR

Loss to follow-up:
Not reported: It seems that for all participants data was included, but it was not mentioned whether there were eligible patients who were excluded due to, for example, technical failure or withdrawal

Percentage of missing items/total scores/outcome:
1.7% of arterial pressure data pairs excluded because of

artifacts or technical problems during signal recording with

the vascular unloading technology or the arterial catheter (not further specified)

Floor effects (% of sample with the lowest score possible):
I: NR
Reason:
C: NR
Reason:

Ceiling effects (% of sample with the highest score possible):

I: NR
Reason:
C: NR
Reason:

Minimally important change/difference:
I: NR
Reason:
C: NR
Reason:

Criterion validity:

Bland altman, mean of the difference (SD, 95%CI)

Mean arterial pressure:
1.1 mm Hg

(7.4, -13.5 to 15.6)

Systolic arterial pressure:

6.8 mm Hg

(10.3, -14.4 to 27.9)

Diastolic arterial pressure:

0.8 mm Hg

(6.9, -12.9 to 14.4)

Responsiveness:

definition: Concordance rate (95%CI)

Mean arterial pressure:
93% (89 to 96%)
systolic arterial pressure
93% (89-97%)
diastolic arterial pressure (88% (84-92%)

Clinical impact outcome measures:

definition: grid error analysis:
the error grid analysis enables a risk level to

be assigned to each pair of measured arterial pressure value

(test method) and “true” arterial pressure value (reference

method) for systolic arterial pressure and MAP (A: no risk; B: low risk; C: moderate risk;

D: significant risk; E: dangerous risk)

Mean arterial pressure:

Zone A: 89.5%

Zone B: 10.0%

Zone C: 0.5%

Zone D: 0%

Zone E: 0%

Systolic arterial pressure:

Zone A: 93.7%

Zone B: 6.0%

Zone C: 0.3%

Zone D: 0%

Zone E: 0%

Diastolic arterial pressure:

Not reported

Author’s conclusion:

In conclusion, the accuracy and precision of the vascular

unloading technology (Clearsight system) was good for MAP

and diastolic arterial pressure, but only moderate for systolic

arterial pressure during laparoscopic bariatric surgery. The

system showed good trending capabilities. According to

error grid analysis, >99% of Clearsight arterial pressure measurements

were categorized in no- or low-risk zones.

Schumann, 2021

Instrument assessed:

1. oscillometric blood pressure, upper arm
2. oscillometric blood pressure, lower arm
3. oscillometric blood pressure, finger cuff

Setting and Country:

Not reported: authors are from Boston, Massachusetts; Munich, German; New York, New York; Irvine, California; Hamburg, Germany; Cleveland, Ohio

Funding and conflicts of interest:

Funding:
BMEYE B.V. (Amsterdam, The Netherlands)—now

Edwards Lifesciences (Irvine, California)—provided the

technical equipment for the study.

Conflicts of interest:
Dr. Schumann receives royalties as author and reviewer for obesity and sleep medicine related chapters in Up-To-Date (Wolters Kluwer; Waltham, Massachusetts). Dr. Wesselink is an employee of Edwards Lifesciences (Irvine, California). Dr. Saugel has received honoraria for consulting, honoraria

for giving lectures, and refunds of travel expenses from

Edwards Lifesciences; honoraria for consulting, institutional

restricted research grants, honoraria for giving lectures, and

refunds of travel expenses from Pulsion Medical Systems SE (Feldkirchen, Germany); institutional restricted research

grants, honoraria for giving lectures, and refunds of travel

expenses from CNSystems Medizintechnik GmbH (Graz,

Austria); institutional restricted research grants from Retia

Medical LLC (Valhalla, New York); honoraria for giving

lectures from Philips Medizin Systeme B.blingen GmbH

(B.blingen, Germany); and honoraria for consulting, institutional

restricted research grants, and refunds of travel

expenses from Tensys Medical Inc. (San Diego, California).

The other authors declare no competing interests.

Inclusion criteria:

• adult patients
• BMI ≥ 40kg/m²
• Scheduled for elective laparoscopi bariatric surgery (gastric bypass, sleeve gastrectomy and gastric branding)
• American Society of Anesthesiologists Physical Status classification < IV

Exclusion criteria:

• Presence of peripheral upper or lower extremity edema
• Vascular of anatomical abnormalities
• History of ipsilateral axillary or inguinal lymph node dissection
• Carpal tunnel syndrome
• Negative modifies Allen test and absence of a palpable ipsilateral ulnar pulse
• Atrial fibrillation

Sample size:

N=108
(90 included in the final protocol)

Age in years (mean (SD; range)):

47 (13)

Gender (n,%):
Male: 26 (29%)

BMI (mean, SD) in kg/m²:

48 (7) kg/m²

Disease:

NA

Disease duration (mean (SD) in years:

NA

Disease severity:

NA

Describe the assessed instrument and used procedures.

I1:

Name:

Continuous noninvasive finger cuff blood pressure:
mean arterial pressure; systolic blood pressure, diastolic blood pressure at 6 different time points (within 15 min before abdominal insufflation in the horizontal

position; 3, 15, 30, and 45 min after the beginning of

insufflation in the 30Åã reverse Trendelenburg position; and

3 min after desufflation in the horizontal position)

Version (including language if applicable):

ccNexfin (BMEYE B.V., The Netherlands); now ClearSight (Edwards Lifesciences,

USA)

Construct:

Non-invasive blood pressure

Specification of investigated component/

Specification of time, occasion, user:
system uses an inflatable

finger cuff with an infrared plethysmograph to measure the

blood volume in the finger arteries, keep the blood volume

constant throughout the cardiac cycle based on an automated

feedback system that inflates and deflates the finger

cuff, and indirectly reconstruct the blood pressure waveform

based on the required cuff pressure. The finger cuff

was fitted and placed on the middle phalanx of the third or

fourth finger according to the manufacturer’s specification

for proper fit. The heart reference system that compensates

for hydrostatic pressure differences between the level of the

heart and the finger cuff was positioned at the level of the

right atrium during the entire study period. Finger cuff blood pressure

measurements were displayed on and extracted from the

proprietary monitor of the ccNexfin system.

Hypothesis (construct validity hypothesis testing):
Not reported

I2:

Name:

Intermittent noninvasive oscillometric upper arm

Version (including language if applicable):

Criticon; GE Healthcare, USA

Construct:

Nonivasive blood pressure:
mean arterial pressure; systolic blood pressure, diastolic blood pressure at 6 different time points (within 15 min before abdominal insufflation in the horizontal

position; 3, 15, 30, and 45 min after the beginning of

insufflation in the 30Åã reverse Trendelenburg position; and

3 min after desufflation in the horizontal position)

Specification of investigated component/

Specification of time, occasion, user:
Measured using a standard large cuff. To reflect

daily clinical practice, cuff fit was accepted when blood pressure

measurements could be obtained. A cuff that would not allow

for circumferential closure or that would spontaneously come

undone during an inflation cycle despite the most feasible limb

alignment was considered a cuff failure for that limb site, and

no aids such as tape were used to rescue potential measurements.

Oscillometric lower leg blood pressure measurements

obtained during steep reverse Trendelenburg positioning were

not included in the analysis because hydrostatic pressure differences

would have influenced the difference between lower leg

and intraarterial blood pressure measurements. Blood pressure measurements were displayed on the

patient monitor (Philips Intellivue MP 90 anesthesia monitor;

Philips Healthcare, USA).

Hypothesis (construct validity hypothesis testing): Not reported

I3:

Name:

Intermittent noninvasive oscillometric lower arm

Version (including language if applicable):

Criticon; GE Healthcare, USA

Construct:

Nonivasive blood pressure: :
mean arterial pressure; systolic blood pressure, diastolic blood pressure at 6 different time points (within 15 min before abdominal insufflation in the horizontal

position; 3, 15, 30, and 45 min after the beginning of

insufflation in the 30^o reverse Trendelenburg position; and

3 min after desufflation in the horizontal position)

Specification of investigated component/

Specification of time, occasion, user:
Measured using a standard cuff. To reflect

daily clinical practice, cuff fit was accepted when blood pressure

measurements could be obtained. A cuff that would not allow

for circumferential closure or that would spontaneously come

undone during an inflation cycle despite the most feasible limb

alignment was considered a cuff failure for that limb site, and

no aids such as tape were used to rescue potential measurements.

Oscillometric lower leg blood pressure measurements

obtained during steep reverse Trendelenburg positioning were

not included in the analysis because hydrostatic pressure differences

would have influenced the difference between lower leg

and intraarterial blood pressure measurements. Blood pressure measurements were displayed on the

patient monitor (Philips Intellivue MP 90 anesthesia monitor;

Philips Healthcare, USA).

Hypothesis (construct validity hypothesis testing): Not reported

Describe the assessed instrument and used procedures.

Name:

Radial artery catheter

Version (including language if applicable):

20-gauge arterial catheter

Construct:

Intraarterial blood pressure:
mean arterial pressure; systolic blood pressure, diastolic blood pressure at 6 different time points (within 15 min before abdominal insufflation in the horizontal

position; 3, 15, 30, and 45 min after the beginning of

insufflation in the 30Åã reverse Trendelenburg position; and

3 min after desufflation in the horizontal position)

Specification of investigated component/

Specification of time, occasion, user:

a 20-gauge arterial catheter was inserted in the radial artery

after induction of general anesthesia and connected it to a

disposable pressure transducer. The pressure transducer was

leveled to the level of the right atrium throughout the study.

The transducer system was examined for its damping properties

with a fast flush test, and, if necessary, actions were taken to correct abnormal damping. Blood pressure measurements were displayed on the

patient monitor (Philips Intellivue MP 90 anesthesia monitor;

Philips Healthcare, USA).

Length of follow-up:

NA

Distribution of scores:

Systolic blood pressure mean(SD) min to max, n_measurements:

I1: 109 (21) 46 to 187, 538

I2: 110 (18) 60 to 167, 443

I3: 113 (18) 61 to 200, 535

C: 117 (21), 55 to 202, 538

Diastolic blood pressure mean(SD), min to max, n_measurements:

I1: 67(13) 30 to 106, 538

I2: 75 (15) 41 to  129, 443

I3: 69 (14) 11 to 443, 537

Mean arterial pressure (SD) min to max, n_measurements:
I1: 83(16) 39 to 136, 538

I2: 124 (24) 78 to 195, 446

I3: 79 (14) 44 to 126, 537

Loss to follow-up:
N=18
Reason: technical difficulties with the insertion of the arterial catheter (n=11); technical

failures with blood pressure monitoring equipment during

the procedure (n = 3); change of the surgical procedure

(n = 1); patient’s withdrawal from participation (n = 1);

discovery of missed exclusion criterion (n = 1); and case

canceled (n = 1).

Percentage of missing items/total scores/outcome:
I1:
missing values: 2
reasons: not reported

I2:
missing values: 97
reasons:

N_participants=8, cuff failure

N_participants, cuff to small

I3:

Missing values: 5
reasons:

N_participants, cuff failure

C:
missing values: 2
reasons: not reported

Floor effects (% of sample with the lowest score possible):
Not reported

Ceiling effects (% of sample with the highest score possible):

Not reported

Minimally important change/difference:
Not reported:

Criterion validity:

Definition: mean of the difference (SD; 95% limits of agreement):

I1 vs C:
systolic blood pressure: -7 (14; -35 to 20)
diastolic blood pressure: 0 (11; -22 to 22)
mean arterial pressure: -1 (11; -23 to 21)

I2 vs C:
systolic blood pressure: -7 (18; -43 to 29)
diastolic blood pressure: -3 (15; -32 to 26)
mean arterial pressure: -9 (15) -38 to 20)
I2 vs C:
systolic blood pressure: -4 (15; -33 to 26)
diastolic blood pressure: 2 (12; -22 to 26)
mean arterial pressure: -5 (13; -29 to 20)

definition: pearson correlation coefficient
I1 vs C:
systolic blood pressure: 0.75
diastolic blood pressure: 0.63
mean arterial pressure: 0.75
I2 vs C:
systolic blood pressure: 0.60
diastolic blood pressure: 0.50
mean arterial pressure: 0.57

I3 vs C:

systolic blood pressure: 0.71
diastolic blood pressure: 0.61
mean arterial pressure: 0.67

Responsiveness:
definition: concordance rate
I1 vs C:
systolic blood pressure: 0.85
diastolic blood pressure: 0.81
mean arterial pressure: 0.88
I2 vs C:
systolic blood pressure: 0.75
diastolic blood pressure: 0.72
mean arterial pressure: 0.75

I3 vs C:

systolic blood pressure: 0.78
diastolic blood pressure: 0.77
mean arterial pressure: 0.78

Clinical impact outcome measures:

definition: Error grid analysis (%(n))
the risk for patients resulting from therapeutic interventions that may be triggered by measurement

differences between the investigated method and the

reference method
A: no risk; B: low risk; C: moderate risk;

D: significant risk; E: dangerous risk
I1 vs C:
systolic blood pressure:
A: 89.5% (481)

B: 9.8% (53)

C: 0.2% (1)
D: 0.4% (2)
E: 0.2% (1)
mean arterial blood pressure:
A: 77.1% (415)

B: 21.6% (116)

C: 0.9% (5)
D: 0.4% (2)
E: 0.0% (0)

I2 vs C:

systolic blood pressure:
A: 85.1% (377)

B: 10.0% (44)

C: 3.8% (17)
D: 1.1% (5)
E: 0.0% (0)
mean arterial blood pressure:
A: 65.9% (294)

B: 28.3% (126)

C: 4.8% (18)
D: 1.6% (7)
E: 0.2% (1)

I3 vs C:

systolic blood pressure:
A: 85.8% (459)

B: 10.2% (60)

C: 2.8% (15)
D: 0.2% (1)
E: 0.0% (0)
mean arterial blood pressure:
A: 74.5% (400)

B: 22.2% (119)

C: 3.0% (16)
D: 0.4% (2)
E: 0.0% (0)

Hypothesis:
“The agreement between finger cuff (I1) and intraarterial

Measurements (C) is better than the agreement between oscillometric (I2+I3) and

intraarterial measurements (C)“

“Patients in our study reflect a typical bariatric surgical

population, rather than obese patients across an extended

age range, with possibly advanced cardiovascular comorbid

conditions presenting for a broader range of general surgical

procedures. Such a relatively selected study population may limit the generalizability of our findings.”

“In conclusion, the agreement between finger cuff and

intraarterial measurements was better than the agreement

between oscillometric and intraarterial measurements for

mean arterial pressure and diastolic blood pressure in obese

patients during surgery. In these patients, forearm oscillometry

exhibits better measurement performance than upper

arm or lower leg oscillometry.”

Risk or bias: Criterion validity

For continuous scores: Were correlations, or the area under the receiver operating curve calculated?

Very good: Correlations or AUC calculated

Inadequate: Correlations or AUC not calculated

Not applicable (fill box dichotomous scores)

For dichotomous scores: Were sensitivity and specificity determined?

Very good: Sensitivity and specificity calculated

Inadequate: Sensitivity and specificity not calculated

Not applicable (fill box continuous scores)

Were there any other important flaws in the design or statistical methods of the study?

Very good: No other important methodological flaws

Doubtful: Other minor methodological flaws

Inadequate: Other important methodological flaws

Overall rating (lowest score)

Eley, 2021

(I1 vs C)

Inadequate

(No correlation or AUC reported)

NA

Very good

Inadequate

Hager, 2009
(I3 vs C)

Very good
(Correlation coefficient calculated)

NA

Very good

Very good

Hansen, 2022

(i1 vs C)

Very good
(Pearson correlation coefficient calculated)

NA

Doubtful
(four participants excluded without reported reasons)

Doubtful

Hansen, 2022

(I2 vs C)

Very good
(Pearson correlation coefficient calculated)

NA

Doubtful

(relatively large number of missing values; four participants excluded without reported reasons)

Doubtful

Mostafa, 2020

(I2 vs C)

Very good
(Correlation coefficient calculated)

NA

Very good

Very good

Mostafa, 2020

(I3 vs C)

Very good
(Correlation coefficient calculated)

NA

Very good

Very good

Rogge, 2019

(I1 vs C)

Inadequate
(No correlation or AUC reported)

NA

Very good

Inadequate

Schuman, 2021

(I1 vs C)

Very good
(Correlation coefficient calculated)

NA

Very good

Very good

Schuman, 2021

(I2 vs C)

Very good
(Correlation coefficient calculated)

NA

Doubtful

(relatively large number of missing values)

Doubtful

Schuman, 2021

(I3 vs C)

Very good
(Correlation coefficient calculated)

NA

Very good

Very good

Risk or bias: Responsiveness (criterion approach (i.e. comparison to a gold standard)

For continuous scores: Were correlations between change scores, or the area under the Receiver Operator Curve (ROC) curve calculated?

Very good: Correlations or AUC calculated

Inadequate: Correlations or AUC not calculated

Not applicable (fill box dichotomous scores)

For dichotomous scales: Were sensitivity and specificity (changed versus not changed) determined?

Very good: Sensitivity and specificity calculated

Inadequate: Sensitivity and specificity not calculated

Not applicable (fill box continuous scores)

Were there any other important flaws in the design or statistical methods of the study?

Very good: No other important methodological flaws

Doubtful: Other minor methodological flaws

Inadequate: Other important methodological flaws

Overall rating (lowest score)

Eley, 2021

(i1 vs C)

Inadequate
(% concordant pairs for direction of change calculated)

NA

Very good

Inadequate

Hansen, 2022

(I1 vs C)

Inadequate
(% concordant pairs for direction of change calculated)

NA

Very good

Inadequate

Hansen, 2022

(I2 vs C)

Inadequate
(% concordant pairs for direction of change calculated)

NA

Doubtful

(relatively large number of missing values)

Inadequate

Mostafa, 2020

(I2 vs C)

Very good
(Correlation coefficient calculated)

NA

Very good

Very good

Mostafa, 2020

(I3 vs C)

Very good
(Correlation coefficient calculated)

NA

Very good

Very good

Rogge, 2019

(I1 vs C)

Inadequate
(% concordant pairs for direction of change calculated)

NA

Very good

Inadequate

Schuman, 2021

(I1 vs C)

Inadequate
(% concordant pairs for direction of change calculated)

NA

Very good

Inadequate

Schuman, 2021

(I2 vs C)

Inadequate
(% concordant pairs for direction of change calculated)

NA

Doubtful

(relatively large number of missing values)

Inadequate

Schuman, 2021

(I3 vs C)

Inadequate
(% concordant pairs for direction of change calculated)

NA

Very good

Inadequate