Table 1 The table summarizes the limitations of previous research and indicates whether the study exhibits specific pitfalls. The pitfalls are categorized into four categories: a) Data-split: Domain Overlap (denoted as D.O), Data Overlap (denoted as C.O), or Small test set (denoted as S.T). b) Over-constraining: SBP values and standard deviation (if provided) c) Unrealistic Pre-Processing: % of remaining dataset after pre-processing (if provided) d) Calibration: Correctly employed and justified for longer periods. The columns denote the presence or absence of each limitation, with Y (yes) indicating that the study has the limitation, N (no) indicating that it does not have that limitation, U (unknown) indicating that there is not enough information available, and “-” indicating that the research is not applicable to the pitfall. For additional information, please see Section Review of the results and limitations of prior work.

From: Examining the challenges of blood pressure estimation via photoplethysmogram

Method

Dataset

Results (SBP)

Data-split

Over-constraining

Unrealistic Pre-Proc.

Calibration

BiGRU Attention30

MIMIC-II

MAE=2.58 SD=3.35

U

N

SD=14.1

N

\(\sim\)10%

AdaBoost31

MIMIC-II

ME=0.09 MAE=8.22 SD=10.38

N

D.O

Y

Y

ANN32

MIMIC-II

MAE=3.21 RMSE=4.23

U

Y

N

\(\sim\)75%

LSTM33

MIMIC-II

MAE=3.23 STD=4.75

U

U

Y

Ensemble CNN34

MIMIC-III

MAE=9.43

Y

S.T

Y

N

\(\sim\)1.7%

ANN35

MIMIC

MAE=4.02 SD=2.79

U

S.T

U

Y

Regression36

Custom Dataset

MAE=6.90 SD=9.00

Y

S.T

Y

Y

SVR37

Queensland

ME=11.6 SD=8.20

Y

S.T

Y

Y

Regression38

Custom Dataset

MAE=3.90 SD=5.37

Y

S.T

N

Y

ANN39

MIMIC-II

ME=0.16 MAE=4.47 SD=6.85

N

C.O

U

Y

SVR40

Custom Dataset

ME=5.10 SD=4.30

Y

S.T

N

SD=11.9

Y

SVR41

Queensland

MAE=4.76 SD=7.68

N

D.O

S.T

N

Y

Math Models42

Custom Dataset

MAE=7.66

Y

S.T

N

SD=12.5

Y

ANN43

MIMIC

MAE=3.80 SD=3.46

U

S.T

N

N

Regression44

MIMIC

MAE=4.90 SD=6.59

N

D.O

S.T

Y

Y

N

LSTM-CNN45

MIMIC-II

ME=1.55 SD=5.41

U

S.T

N

N

\(\sim\)15%

AdaBoost46

MIMIC-II

ME= -0.05 SD=8.90

N

D.O

Y

N

\(\sim\)20%

U-Net21

MIMIC-II

ME=-1.58 SD=8.61

N

C.O

Y

Y

CNN Siamese27

MIMIC-II

MAE=5.95 SD=6.90 [Calib]

Y

N

N

\(\sim\)5%

N

U-Net29

MIMIC-II

ME=4.30 SD=6.50

Y

N

SD=13.5

Y

1-D CNN47

Custom Dataset

SD=11.4

N

D.O

S.T

N

SD=16

Y

LSTM48

MIMIC-II

ME=4.05 SD=4.60

N

D.O

S.T

N

N

\(\sim\)50%