The reliability of clinical dynamic monitoring of redox status using a new redox potential (ORP) determination method

Figures & data

Table 1. Demographic and clinical characteristics of the cohort of 30 severe burn patients

Case	Age	Sex (M/F)	TBSA (%: II–III°)	ABSI	SOFA	Shock symptoms(Y/N)	Early operation(Y/N)	Sepsis(Y/N)	Lethal(Y/N)
Case 1	44	M	56	11	7	Y	N	N	N
Case 2	36	M	65	11	6	Y	N	N	N
Case 3	35	M	60	10	6	Y	N	N	N
Case 4	30	M	60	10	7	Y	N	N	N
Case 5	34	M	42	9	7	Y	N	N	N
Case 6	45	M	45	10	5	Y	N	N	N
Case 7	43	M	52	11	6	Y	N	N	N
Case 8	33	M	50	9	6	Y	N	N	N
Case 9	39	M	60	10	5	Y	N	N	N
Case 10	45	M	55	11	6	Y	N	N	N
Case 11	31	F	44	8	4	Y	N	N	N
Case 12	40	M	57	10	5	Y	N	N	N
Case 13	42	F	67	11	5	Y	N	N	N
Case 14	30	F	43	8	6	Y	N	N	N
Case 15	45	M	60	11	6	Y	N	N	N
Case 16	32	M	45	10	5	Y	Y	N	N
Case 17	39	M	50	9	6	Y	Y	N	N
Case 18	38	F	45	9	5	Y	Y	N	N
Case 19	31	M	46	9	5	Y	Y	N	N
Case 20	34	F	50	8	5	Y	Y	N	N
Case 21	37	M	45	9	5	Y	Y	N	N
Case 22	41	M	40	9	4	Y	Y	N	N
Case 23	38	M	50	9	5	Y	Y	N	N
Case 24	42	M	86	14	8	Y	N	Y	Y
Case 25	39	F	70	10	8	Y	N	Y	Y
Case 26	45	M	90	14	10	Y	N	Y	Y
Case 27	37	M	83	13	10	Y	N	Y	Y
Case 28	40	M	93	15	10	Y	N	Y	Y
Case 29	42	M	65	12	8	Y	N	N	Y
Case 30	43	M	60	11	8	Y	N	N	Y

M, male; F, female; TBSA, total burn surface area; ABSI, Abbreviated Burn Severity Index; SOFA, Sepsis-related Organ Failure Assessment Group.

Table 2. Demographic and clinical characteristics of the cohort of 20 mild burn patients

Case	Age	Sex (M/F)	TBSA (%: I–II°)	ABSI
Case 1	41	M	6	5
Case 2	30	M	7	4
Case 3	32	M	5	4
Case 4	41	F	6	4
Case 5	34	F	5	3
Case 6	43	M	6	5
Case 7	32	M	5	4
Case 8	33	M	7	4
Case 9	36	F	6	3
Case 10	42	M	8	5
Case 11	32	M	6	4
Case 12	45	M	7	5
Case 13	33	M	6	4
Case 14	31	F	5	3
Case 15	34	M	7	4
Case 16	42	M	5	5
Case 17	32	M	8	4
Case 18	37	M	7	4
Case 19	42	M	6	5
Case 20	33	M	6	4

M, male; F, female; TBSA, total burn surface area; ABSI, Abbreviated Burn Severity Index.

Table 3. Stability of measurements using the depolarization curve method and improved traditional method using blood samples from a healthy person or redox reference solution

	ORP (mV)			ΔORP (mV)
	Mean value	SD	CV (%)	Mean value	SD	CV (%)
Plasma^Citation1	170.3	3.47	2.0
Plasma^Citation2	169.1	4.61	2.7
Diluted plasma^Citation1	300.6	3.84	1.3
Diluted plasma^Citation2	299.3	4.85	1.6
Diluted plasma^Citation3				138.2	2.90	2.1
Diluted plasma^Citation4				139.8	3.29	2.4
rr solution	439.7	1.34	0.3
rr solution*	437.9	2.64	0.6

The results of 10 continuous determinations of blood samples from a healthy male and redox reference solution using the depolarization curve method (ORP) or improved traditional method (ΔORP) are shown.

The experiments were conducted at room temperature (25°C).

SD, standard deviation.

Plasma¹, 4 ml of plasma; plasma², 4 ml of plasma (after one day of storage at −80°C); diluted plasma¹, 1 ml of plasma + 3 ml of NS (normal saline); diluted plasma², 1 ml of plasma + 3 ml of NS (after one day of storage at −80°C); diluted plasma³: 1 ml of plasma + 5 ml of blank solution (Lactated Ringer's solution); diluted plasma⁴: 1 ml of plasma + 5 ml of blank solution (after one day of storage at −80°C); rr solution, redox reference solution; rr solution*, preserved after 6 months.

Table 4. Stability of measurements of the depolarization curve method using plasma samples from eight mild burn patients

Case	1	2	3	4	5	6	7	8
Mean ORP (mV)	187	203.5	204.3	184.4	205.5	185.7	194.6	205.9
SD	3.8	4.03	4.16	4.17	4.43	3.77	3.89	4.18
CV (%)	2	2	2	2.3	2.2	2	2	2

The results of 10 continuous determinations using plasma samples from eight mild burn patients are shown.

The experiments were conducted at room temperature (25°C).

Case: mild burn patient.

4 ml of plasma was used for each measurement.

SD, standard deviation.

Table 5. Stability of measurements of the depolarization curve method using diluted plasma samples from eight mild burn patients

Case	1	2	3	4	5	6	7	8
Mean ORP (mV)	304.9	309.5	310.7	297.9	311	300.9	305.2	310.8
SD	4.56	4.3	4.03	4.86	4.94	4.43	4.59	4.21
CV (%)	1.5	1.4	1.3	1.6	1.6	1.5	1.5	1.4

The results of 10 continuous determinations using diluted plasma samples from eight mild burn patients are shown.

The experiments were conducted at room temperature (25°C).

Case: mild burn patient.

Diluted plasma, 1 ml of plasma + 3 ml of NS (normal saline).

SD, standard deviation.

Table 6. Electrochemical specificity of the depolarization curve method in KMnO₄/vitamin C redox titration experiments

	Added KMnO4 (μg)	PH	ORP (mV)		Added Vitamin C (mg)	PH	ORP (mV)
NS	0	5.6	409		0	5.4	401
	25	5.18	722		2.5	5.43	295
	50	4.74	993		5	5.88	247
					10	6.52	227
Diluted plasma^Citation1	0	7.81	302	Diluted plasma^Citation2	0	7.82	365
	5	7.9	327		2.5	7.52	258
	50	7.92	351		5	7.57	182
	100	7.93	375		10	7.61	161

The results of the KMnO₄/Vitamin C redox titration experiment using NS and diluted plasma from one mild burn patient are shown.

The experiments were conducted at room temperature (25°C).

NS, normal saline.

Diluted plasma¹, 1 ml of plasma + 3 ml of NS; Diluted plasma², 1 ml of plasma + 9 ml of NS.

Table 7. Electrochemical specificity of the improved traditional method in KMnO₄/Vitamin C redox titration experiments

	Added KMnO4 (μg)	PH	Eh (mV)	Added Vitamin C (mg)	PH	Eh (mV)	Added plasma (ml)	PH	Eh (mV)
5 ml of blank solution	0	7.7	205	0	7.7	183	0	7.7	180
5 ml of blank solution	25	7.8	436	20	7.62	−140	1	7.78	43
ΔORP (mV)			−231			323			137

The results of KMnO₄/vitamin C and plasma (from one mild burn patient) redox titration experiments using the blank solution are shown. The ΔORP of the blank solution changed with the addition of KMnO₄, vitamin C or plasma.

The experiments were conducted at room temperature (25°C).

Eh, reduction potential.

blank solution, Lactated Ringer's solution.

Figure 1. (A) Changes in the ORP in 15 severe burn patients without early Escher-shaving operation during the shock stage. (B) Changes in the ΔORP in 15 severe burn patients without early Escher-shaving operation during the shock stage. (C) Changes in the UA levels in 15 severe burn patients without early Escher-shaving operation during the shock stage. (D) Changes in the methemoglobin (Met-Hb) levels in 23 severe burn patients (with and without early Eschar-shaving operation) during the shock stage. (E) Changes in the ORP in 8 severe burn patients who underwent early Eschar-shaving operations during the shock stage. (F) Changes in the ΔORP in eight severe burn patients who underwent early Eschar-shaving operations during the shock stage. The known group validity according to dynamic monitoring of the ORP, ΔORP, uric acid level and methemoglobin (Met-Hb) content of plasma samples from 23 severe burn patients (with and without early Escher-shaving operation) during the shock stage is shown. For the ORP, diluted plasma samples (1 ml of plasma + 3 ml of normal saline) were used. For the ΔORP, uric acid level and methemoglobin (Met-Hb) content, plasma samples were used. Plasma samples were consecutively collected from 23 severe burn patients for approximately 7 days before and after fluid treatment during the shock stage (mean ± SD). The data are presented according to the time of day: d0 (within six hours after injury, no anti-shock fluid treatment had been administered), d1 (1 day after injury and anti-shock fluid treatment), and d3, d5, d7, and d9 (3, 5, 7, and 9 days after injury and anti-shock fluid treatment, respectively). Discharge represents the data at discharge. The abscissa axis is time (day). The close correlations between the plasma ORP and ΔORP measurements and the UA levels were confirmed (P < 0.05).

Figure 2. (A) Dynamic changes in the ORP (compared with d0) in five severe burn patients in late sepsis. (B) Dynamic changes in the Met-Hb levels in five severe burn patients in late sepsis. (C) Dynamic changes in the ΔORP in five severe burn patients in late sepsis. (D) Dynamic changes in the uric acid levels in five severe burn patients in late sepsis. The known group validity according to the dynamic monitoring of the ORP, ΔORP, uric acid level and methemoglobin (Met-Hb) content of plasma samples of five severe burn patients in late sepsis prior to death is shown. For the ORP, diluted plasma samples (1 ml of plasma + 3 ml normal saline) were used. For the ΔORP, uric acid level and methemoglobin (Met-Hb) content, plasma samples were used. Plasma samples were consecutively collected from five severe burn patients in late sepsis prior to death. The data are presented by the time of day: day 1 (one day before death), day 3 (the third day before death), and day 5 (the fifth day before death). The abscissa axis is time (day). The change trend along with progress of disease is shown.

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