Evaluation of Biomarkers from Peritoneal Fluid as Predictors of Severity for Abdominal Sepsis Patients Following Emergency Laparotomy

Figures & data

Table 1 Baseline Characteristics

Characteristic	Abdominal Infection (n=16)	Abdominal Sepsis (n=25)	Abdominal Septic Shock (n=17)
Male, No./total No. (%)	8/16 (50%)	18/25 (72%)	9/17 (52%)
Age, mean (SD), y	58.75±17.52	68.6±14.89	65.10±15.28
SOFA score, mean (SD)	1.18±1.32	8.28±7.48	14.47±7.35
APACHE II score, mean (SD)	9.33±1.03	13.12±1.55	18.00±1.54
Type of admission, No./total No. (%)
Perforation	14/16 (87%)	14/25 (56%)	10/17 (59%)
Acute intestinal obstruction	2/16 (13%)	8/25 (32%)	2/17 (11%)
Anastomotic leakage	0	3/25 (12%)	3/17 (17%)
Rupture of liver abscess	0	0	2/17 (11%)
Organ dysfunction, No.
Circulation/ Microcirculatory	0	6	6
Respiratory	1	5	4
Coagulation	0	1	2
Liver	0	1	1
Renal	0	6	5
Central nervous system	0	0	1
Species distribution of pathogens isolated from patients with bloodstream infections
Gram-negative bacteria
Escherichia coli	0	8	4
Pseudomonas aeruginosa	0	4	1
Klebsiella pneumoniae	0	2	0
Enterobacter cloacae	0	0	1
Gram-positive bacteria
Enterococci	0	3	3
Staphylococcus aureus	0	1	1
Fungi
Candida albicans	0	0	2

Abbreviations: APACHE II, Acute Physiology and Chronic Health Evaluation II; SOFA, Sequential Organ Failure Assessment.

Figure 1 Baseline characteristics of abdominal infection in patients after laparotomy. There were no sex-based differences between the three groups (a), but patients with abdominal sepsis were older than those in the only infection group (b). The APACHE II score was higher in the sepsis and septic shock groups, especially the septic shock group. The SOFA score was only higher between the non-sepsis group and the sepsis or septic group (c). The causes of abdominal infection are shown in (d). Positive blood microbiological data are shown, but no significant differences in microorganism cultures were observed between the sepsis group and the septic shock group (e). No differences were found in patients with and without organ dysfunction between these two groups (f). *p<0.005 abdominal-infectious control vs sepsis groups. **p<0.005 sepsis group vs abdominal septic shock group.

Table 2 Primary and Secondary End Points

End Point	Abdominal Infection^a (n=16)	Abdominal Sepsis^b (n=25)	Abdominal Septic Shock^c (n=17)	P values ^ab, ac
Primary outcome
90-day Mortality, No./total No. (%)	0/16	2/25 (8%)	5/17 (29.4%)	0.017 ^ab,0.025 ^ac
Secondary outcome
Length of stay in ICU, median, day	1.5±0.81	8.4±5.6	17.5±9.6	0.003^ac
Mechanical ventilation free time, median, day	1.0±0.1	1.6±1.2	2.7±2.0	NS
Required Renal Replacement Treatment, No	0	1	2	NS
Duration of vasoactive drugs in days, median	0±0	1.1±0.35	1.45±1.03	0.009 ^ab,0.01 ^ac
Adverse Events
Secondary abdominal infections, No.	0	3	5
Intestinal obstruction, No.	0	2	2
Pneumonia, No.	0	5	7
Anastomotic fistula, No.	0	2	1
Gastrointestinal bleeding	0	2	3
Cerebrovascular disease, No.	0	0	1

Notes: P ^abValue between abdominal infection group and sepsis group (t-test). P ^acValue between abdominal infection group and septic shock group (t-test). P value <0.05 is significant.

Figure 2 Outcomes and serious adverse events of abdominal infection after laparotomy. Mortality was significantly higher in the septic shock group compared to the other two groups (a). There were more vasopressors administered in the sepsis or septic group compared to the non-sepsis group (b). Adverse events are listed; No significant differences were observed across the three groups (c). *p<0.005 abdominal-infectious control vs sepsis groups. **p<0.005 sepsis group vs abdominal septic shock group.

Table 3 Levels of 14 Biomarkers in the Abdominal Cavity of Enrolled Patients

Cytokine Levels at Admission	Abdominal Infection ^a (n=16)	Abdominal Sepsis ^b (n=25)	Abdominal Septic Shock^c (n=17)	P values ^ab, ac
IL-4 (pg/mL), median	4.48±2.34	32.18±8.78	78.51±25.33	NS
IL-2 (pg/mL), median	3.97±1.21	4.24±0.97	8.57±3.82	0.012^ac,0.018^bc
IP-10 (pg/mL), median	10.80±2.98	143.80±82.95	188.32±28.26	0.043^ac,0.005^bc
IL-1β(pg/mL), median	57.78±24.64	106.55±83.68	305.31±87.56	0.002^ac,0.003^bc
TNF-α(ng/mL), median	1394.0±221.84	2412.7±168.33	3426.9±252.69	0.005^ac,0.002^bc
MCP-1 (pg./mL), median	26.86±9.71	69.92±16.50	115.32±45.22	0.001^ac,0.014^bc
IL-17 (pg/mL), median	14.40±7.51	33.53±4.26	46.05±12.22	0.013^ac,0.001^bc
IL-6 (pg/mL), median	130.51±42.84	316.73±189.42	698.15±220.01	0.003^ac,0.001^bc
IL-10 (pg/mL), median	14.34±10.65	173.53±61.32	382.50±54.86	NS
IFN-γ(pg/mL), median	20.83±9.96	37.03±20.01	58.50±25.14	NS
IL-12 (pg/mL), median	374.72±106.87	392.33±96.42	538.93±235.06	NS
IL-8 (pg/mL), median	28.13±6.02	174.88±52.77	425.74±228.49	0.001^ac
TGF-β(ng/mL), median	179.68±63.02	209.01±60.37	821.23±225.09	0.001^ac
IL-3 (ng/mL), median	977.83±121.73	931.98±200.40	732.97±257.64	NS

Notes: P ^abValue between abdominal infection group and sepsis group (t-test). P ^acValue between abdominal infection group and septic shock group (t-test). P value <0.05 is significant.

Figure 3 Comparative analysis of peritoneal biomarker levels in the different groups. IL-1β, IL-17, IL-2, TNF-α, IL-8, IL-6, MCP-1, IP-10, IL-8, and TGF-β were higher in the sepsis groups compared to the non-sepsis group. Except for IL-8 and TGF-β, these cytokines of the septic shock group were also higher than those of the sepsis group. *p< 0.005 abdominal-infectious control vs abdominal sepsis group. **p< 0.005 sepsis group vs abdominal septic shock group.

Table 4 Correlation Between Peritoneal Cytokines and Severity of Illness Parameters

Cytokine Levels at Admission	APACHE II Score
	R	P value
IL-1β in abdominal fluid	0.429	0.003
IL-2 in abdominal fluid	0.417	0.004
IL-6 in abdominal fluid	0.833	0.001
TNF-α in abdominal fluid	0.766	0.001
MCP-1 in abdominal fluid	0.677	0.001
IL-17 in abdominal fluid	0.622	0.001
IP-10 in abdominal fluid	0.363	0.072
IL-8 in abdominal fluid	0.686	0.001
TGF-βin abdominal fluid	0.377	0.064

Figure 4 Positive correlation between peritoneal biomarkers and predictive risk of severity of sepsis. Peritoneal concentrations of IL-1β, IL-2, TNF-α, IL-8, IL-6, MCP-1, and IL-17 showed positive correlations with APACHE II scores. The correlation coefficients ranged from 0.417 to 0.833.

Table 5 Levels of 14 Biomarkers in the Serum of Enrolled Patients

Cytokine Levels at Admission	Abdominal Infection ^a (n=16)	Abdominal Sepsis ^b (n=25)	Abdominal Septic Shock ^c (n=17)	P values ^ab, ac
IL-4 (pg/mL), median	4.22±1.06	16.20±15.6	17.34±13.21	NS
IL-2 (pg/mL), median	4.62±1.56	3.00±0.59	3.92±1.20	NS
IP-10 (pg/mL), median	72.70±30.78	96.48±48.72	118.72±57.79	NS
IL-1β (pg/mL), median	17.29±7.30	20.83±9.97	37.04±21.02	NS
TNF-α (ng/mL), median	1167.0±213.13	1232.5±278.84	1550.6±158.75	NS
MCP-1 (pg/mL), median	13.09±6.38	55.86±11.09	123.61±63.11	0.043^ac,0.002^bc
IL-17 (pg/mL), median	6.87±0.90	9.08±2.82	15.07±4.32	NS
IL-6 (pg/mL), median	158.82±118.27	310.99±89.78	375.40±196.44	0.015 ^ac
IL-10 (ng/mL), median	852.50±85.04	1480.2±413.49	2248.5±931.02	0.023^ac,0.001^bc
IFN-γ (pg/mL), median	76.35±26.65	77.77±24.64	106.55±83.69	NS
IL-12 (ng/mL), median	755.52±121.83	1075.4±239.59	1516.2±341.96	0.013^ac,0.001^bc
IL-8 (pg/mL), median	264.95±60.21	397.52±57.34	467.75±138.06	0.006^ac
TGF-β (ng/mL), median	788.24±235.83	786.78±157.31	1316.5±260.37	0.001^ac
IL-3 (ng/mL), median	599.76±299.51	673.15±378.98	532.78±171.59	NS

Notes: P ^abValue between abdominal infection group and sepsis group (t-test). P ^acValue between abdominal infection group and septic shock group (t-test). P value <0.05 is significant.

Table 6 Correlation Between Serum Cytokines and Severity of Illness Parameters

Cytokine Levels at Admission	APACHE II Score
	R	P value
IL-10 in serum	0.592	0.002
IL-12 in serum	0.638	0.001
MCP-1 in serum	0.748	0.001
IL-8 in serum	0.507	0.01
TGF-β in serum	0.543	0.001
IL-6 in serum	0.384	0.583

Figure 5 Comparative analysis of serum biomarker levels in the different groups. Serum levels of IL-10, IL-12, MCP-1, IL-6, IL-8, and TGF-β were increased significantly in septic shock, especially for levels of IL-10, IL-12, and MCP-1 that showed statistical differences between the three groups. *p <0.005 abdominal infectious control vs abdominal sepsis group. **p<0.005 sepsis group vs abdominal septic shock group.

Figure 6 Positive correlation between serum biomarkers and predictive risk of severity of sepsis (APACHE II scores). Serum concentrations of IL-10, IL-12, MCP-1, IL-8, and TGF-β showed positive correlations with APACHE II scores. The correlation coefficients ranged from 0.384 to 0.748.