Low perfusion index affects the difference in glucose level between capillary and venous blood

Figures & data

Table 1 Descriptive statistics related to the participants

Parameters	Number	Mean ± SD	Range
Age	300	59.47±16.41	19.00–97.00
Finger stick blood glucose level* (mg/dL)	300	179.33±110.36	36.00–900.00
Venous glucose level (mg/dL)	274	196.08±130.16	18.00–895.00
Perfusion index**	300	4.56±3.59	0–30

Notes:

* By Abbott Optium Exceed.

** By Masimo Radical-7^®.

Abbreviation: SD, standard deviation.

Figure 1 (A) Venous and capillary glucose level comparability in all patients with normal vital signs and low perfusion index (0–5) (n=67). (B) Venous and capillary glucose level comparability in patients with normal vital signs and high perfusion index (>5) (n=19).

Notes: (A) Passing and Bablok regression equation y =5.4648+0.9718x. Cusum test for linearity: P>0.10. (B) Passing and Bablok regression equation y =28.2272+0.7923x. Cusum test for linearity: P>0.05.
Abbreviations: CGL, capillary glucose level; VGL, venous glucose level; SD, standard deviation.

Figure 2 (A) Venous and capillary glucose level comparability in patients with at least one abnormal vital sign finding and low perfusion index (n=131). (B) Venous and capillary glucose level comparability in patients with at least one abnormal vital sign finding and high perfusion index (n=57).

Notes: (A) Passing and Bablok regression equation y =13.8113+0.8679x. Cusum test for linearity: P>0.05. (B) Passing and Bablok regression equation y =10.2941+0.8916x. Cusum Test for Linearity: P>0.10.
Abbreviations: CGL, capillary glucose level; VGL, venous glucose level; SD, standard deviation.

Figure 3 (A) Venous and capillary glucose level comparability in younger patients, aged 18–65 years, with perfusion index between 0 and 5 (n=44). (B) Venous and capillary glucose level comparability in older patients, aged >65 years, with perfusion index between 0 and 5 (n=22).

Notes: (A) Passing and Bablok regression equation y =8.3621+0.9310x. Cusum test for linearity: P>0.10. (B) Passing and Bablok regression equation y =1.8347+1.0565x. Cusum test for linearity: P>0.10.
Abbreviations: CGL, capillary glucose level; VGL, venous glucose level; SD, standard deviation.

Figure 4 (A) Venous and capillary glucose level comparability in younger patients, aged 18–65 years, with perfusion index >5 (n=12). (B) Venous and capillary glucose level comparability in older patients, aged >65 years, with perfusion index >5 (n=7).

Notes: (A) Passing and Bablok regression equation y =11.3753+0.8528x. Cusum test for linearity: P>0.10. (B) Passing and Bablok regression equation y =56.1357+0.6953x. Cusum test for linearity: P>0.10.
Abbreviations: CGL, capillary glucose level; VGL, venous glucose level; SD, standard deviation.

Figure 5 (A) Venous and capillary glucose level comparability in younger patients, aged 18–65 years, with at least one abnormal vital sign finding and low perfusion index (n=72). (B) Venous and capillary glucose level comparability in older patients, aged >65 years, with at least one abnormal vital sign finding and low perfusion index (n=59).

Notes: (A) Passing and Bablok regression equation y =13.9138+0.8459x. Cusum test for linearity: P<0.05. (B) Passing and Bablok regression equation y =16.4853+0.8758x. Cusum Test for Linearity: P>0.10.
Abbreviations: CGL, capillary glucose level; VGL, venous glucose level; SD, standard deviation.

Figure 6 (A) Venous and capillary glucose level comparability in younger patients, aged 18–65 years, with at least one abnormal vital sign finding and high perfusion index (n=24). (B) Venous and capillary glucose level comparability in older patients, aged >65 years, with at least one abnormal vital sign finding and high perfusion index (n=33).

Notes: (A) Passing and Bablok regression equation y =7.0950+0.8450x. Cusum test for linearity: P>0.10. (B) Passing and Bablok regression equation y =9.1246+0.9208x. Cusum test for linearity: P>0.10.
Abbreviations: CGL, capillary glucose level; VGL, venous glucose level; SD, standard deviation.

Table 2 Summary of major results

Vital signs*	Perfusion index#	Younger/older groups&	Higher consistency between CGL and VGL in
Normal	Low High	All	Low perfusion index group
Abnormal	Low High	All	High perfusion index group
Normal	Low	Younger Older	Older patients
Normal	High	Younger Older	Younger patients
Abnormal	Low	Younger Older	Younger patients
Abnormal	High	Younger Older	Younger patients

Notes:

* Normal limits of vital signs: systolic blood pressure 120–90 mmHg, pulse rate 60–100/min, respiration rate 12–16/min, body temperature 36.0°C –37.1°C, and oxygen saturation >94%.

# Low perfusion index includes scores 0–5; high perfusion index includes scores >5.

& Younger patients are 18–65 years; older patients are >65 years.

Abbreviations: CGL, capillary glucose level; VGL, venous glucose level.