World Journal of Surgery

, Volume 29, Issue 6, pp 759–765

Protein C as an Early Marker of Severe Septic Complications in Diffuse Secondary Peritonitis

Authors

    • Center for Emergency SurgeryClinical Center of Serbia, School of Medicine, University of Belgrade
  • Dejan Radenkovic
    • Center for Emergency SurgeryClinical Center of Serbia, School of Medicine, University of Belgrade
  • Natasa Milic
    • Institute of Medical StatisticSchool of Medicine, University of Belgrade
  • Vesna Bumbasirevic
    • Institute of AnaesthesiologyClinical Center of Serbia, School of Medicine, University of Belgrade
  • Branislav Stefanovic
    • Center for Emergency SurgeryClinical Center of Serbia, School of Medicine, University of Belgrade
Article

DOI: 10.1007/s00268-005-7771-7

Cite this article as:
Karamarkovic, A., Radenkovic, D., Milic, N. et al. World J. Surg. (2005) 29: 759. doi:10.1007/s00268-005-7771-7

Abstract

To evaluate the predictive value of protein C as a marker of severity in patients with diffuse peritonitis and abdominal sepsis, protein C levels were repeatedly determined and compared with serum levels of antithrombin III, plasminogen, α2-antiplasmin, Plasminogen activator inhibitor, D-dimer, C1-inhibitor, high molecular weight kininogen, and the C5a, C5b-9 fragments of the complement system. We carried out a prospective study from 44 patients with severe peritonitis confirmed by laparotomy and 15 patients undergoing elective ventral hernia repair who acted as controls. Analyzed biochemical parameters were determined before operations and on days 1, 2, 3, 5, 7, 10, and 14 after operations. For the study group, preoperative average protein C level was significantly lower in the patients who developed septic shock in the late course of the disease, with lethal outcome, than in the patients with severe peritonitis and sepsis who survived (p = 0.0001). In non-survivors, protein C activity remained decreased below 70%, whereas the course of survivors was characterized by increased values that were significantly higher (p < 0.03) at every time point than in those patients who died. Protein C was of excellent predictive value and achieved a sensitivity of 80% and a specificity of 87.5% in discriminating survivors from non-survivors within the first 48 hours of the study (AUC-0.917; p < 0.001), with a “cut-off” level of 66.0%. As for the control group, throughout the study period, protein C activity was permanently maintained within the range of normal, with significant differences with reference to the study group (p < 0.01). These results suggest that protein C represents a sensitive and early marker for the prediction of severe septic complications during diffuse peritonitis, and of outcome.

Keywords

protein Cperitonitisseptic abdomenabdominal sepsis

Introduction

Abdominal sepsis is a major trigger of a range of pathophysiological events. Systemic inflammatory reaction to intra-abdominal septic foci is a highly complex phenomenon directed toward anti-infection defense and homeostasis preservation. In cases of intensive bacterial invasion, the systemic response results in excessive production of mediators of inflammation, damage to the tissue perfusion system, and multiple organ dysfunction (MODS) [1]. Despite modern approaches to its treatment, severe secondary peritonitis is burdened with a high incidence of mortality (20%–40%) [24]. Progression of septic shock is associated with even greater mortality rates, ranging from 50% to 70% [3, 4].

The septic cascade is initiated by an inflammatory reaction to bacterial pathogens (endotoxin, cell fragments G+ bacteria) [5]. Tumor Necrosis factor (TNF) and interleukins-1 and -6 (IL-1, IL-6) are the most potent pro-inflammatory cytokines, enabling activation of polymorphonuclear leukocytes, adhesive processes between leukocytes and endothelial cells, protease release, and activation of arachidonic acid and plasmatic cascades (coagulation, fibrinolysis, kinin-kalikrein) [68].

The protein C system plays a crucial role in control of microvascular coagulation and inflammation. It is one of the basic regulatory systems of homeostasis, as it has potent anticoagulant, profibrinolytic, and anti-inflammatory properties [9, 10]. Protein C (PC) inactive precursor and activated protein C (APC), and vitamin-K dependent serine protease with potent biological properties have a central place within the system. Protein C is converted into APC under the influence of thrombin complexes (with thrombomodulin) on the endothelial protein C receptors (EPCR) in the presence of protein S. Normal levels of circulating protein C range from 2800 to 5600 ng/ml (80%–140%), with a 10-hour half-life, as opposed to APC, whose half-life is only 20 minutes, and whose normal circulating levels range between 1 and 3 ng/ml [912].

Activated protein C inactivates coagulation factors Va and VIIIa and neutralizes the effects of plasminogen activator inhibitor1 (PAI-l) [1315]. In addition to its antithrombotic and profibrinolytic properties, APC is also capable of direct anti-inflammatory activity that reduces cytokine production (TNF, MIF [migration inhibitory factor]), thereby inhibiting adhesion of leukocytes to the blood vessel endothelium [9, 10, 15]. As a result of all the above-mentioned mechanisms, APC significantly reduces the processes of microvascular thrombosis and endothelial dysfunction [16]. It blocks the Ca pump, leading to CD-14 monocyte disorders upon endotoxin response to stimulation [17]. In addition, APC binds to protein C mononuclear receptors, blocking TNF production [18]; down regulation of inflammatory response of endothelium after binding of APC to EPCR [17].

Prominent reduction of protein C activity accompanies severe disseminated intravascular coagulation (DIC) and severe forms of the septic syndrome [14, 19, 20]. Levels of circulating protein C and protein S are reduced as a result of increased consumption. Circulating cytokines reduce activity of thrombomodulin and EPCR in the endothelium, which results in reduced protein C activation [9].

Close correlation between diffuse bacterial peritonitis and abdominal sepsis necessitates precise, fast, and complex diagnostic and therapeutic approaches [3, 5]. Therapeutic improvements have been achieved over the last decade owing to a modified and more aggressive surgical approach and use of modern antibiotics. In recent years, however, improvements have been made only in elucidating the pathophysiology of sepsis. Generalized plasmatic proteolysis, which develops as a result of an imbalance in active serine proteases and functional inhibitory systems, and designated as “pathological perfusate,” represents one of the basic pathophysiological disorders accompanying sepsis [21, 22]. Septic cascade, i.e., its inflammatory and coagulation components in severe peritonitis, are initiated before clinical manifestations of sepsis. This knowledge emphasis the significance of establishing early and senstitive markers [23].

Therefore, the aim of this study was to analyze plasmatic cascade disturbances during severe secondary peritonitis with sepsis syndrome and to determine early biochemical markers of sepsis.

Patients and Methods

The study was conducted at the University Center for Emergency Surgery in Belgrade, between September 2001 and June 2003. Research methodology was based on a prospective study of 59 patients classified according to their underlying condition into the following groups:
  1. 1.

    Study group: 44 patients treated surgically for severe secondary peritonitis with sepsis syndrome.

     
  2. 2.

    Control group: 15 patients treated surgically by elective ventral hernia repair, who were free of any signs of the infection syndrome. All the patients underwent laparotomy with general anaesthesia.

     
Inclusion criteria for the study group were diffuse secondary bacterial peritonitis proved by laparotomy and microbiological detection of bacteria in the peritoneal content based on the following criteria: evidence of an abdominal septic focus (infection source or a previous operation causing the peritonitis) and macroscopic findings of peritoneal inflammation and exudation in at least three quadrants of the abdominal cavity. Patients with a diagnoses of traumatic bowel perforation who underwent operation within 12 hours of injury were excluded, as were those with perforation of gastroduodenal ulcers undergoing operation within 24 hours of perforation; and those with simple cholecystitis and appendicitis.

Patients with infected necrotizing pancreatitis and taste for whom planned management by staged abdominal repair (STAR) or the open abdomen technique was scheduled or whose APACHE II score on admission was < 15 points were also excluded from the study. All patients in the study group were operated on within 6 hours of admission to the hospital. Sepsis and septic shock were defined according to, the criteria of the American College of Chest Physicians and the American Society of Critical Care Medicine [24].

Blood Sampling and Measurements

The blood samples for determination of the analyzed parameters were obtained before operation and on postoperative days 1, 2, 3, 5, 7, 10, and 14. All measurements were done with commercially available kits (Dade Behring, Marburg GmbH, Germany), and the solutions were prepared according to the manufacturer’s directions. All assays were done in the Behring Coagulation Timer–BCT System and Behring Nephelometer–BN System (Dade Behring, Marburg GmbH, Germany).

Pathromtin SL reagent was used for determination of activated partial thromboplastin time (aPTT) by the coagulometric method. The reference interval for aPTT is 26 to 36 seconds. Protein C was determined with an automated BCT Analyzer (Behring Coagulation Timer) and Berichrom Protein C reagent. Functional activity of APC was determined according to kinetic testing, measuring an absorption rise to 405 nm. The values are expressed as percentages, normally ranging from 80% to 140% of normal.

In addition to protein C, the following parameters of the plasmatic cascades (coagulation, fibrinolytic, kinin-kalikrein) were monitored and analyzed: antithrombin III (AT III), plasminogen, PAI-1 α2-antiplasmin, D-dimer, HMWK (high molecular weight kininogen), and the C1-inhibitor.

The Berichrom Antithrombin III reagent was used for the spectrophotometric measurement of AT III. The reference interval for AT III is 80%–120% of normal.

The Berichrom Plasminogen test, Berichrom PAI-1, and Berichrom α2-antiplasmin reagents were used for the spectrophotometric measurement of biologically active plasminogen, PAI-1 activity, and functional activity of α2-antiplasmin. Reference intervals for plasminogen, PAI-1 and α2-antiplasmin are 75%–140-% of normal, 0.3–3.5 U/ml and 80%–120%, respectively. D-dimer was determined turbidimetrically by the latex-enhanced turbidimetric D-dimer PLUS test. The upper limit of the reference interval for D-dimer is 246 μg/l.

The Berichrom HMWK and Berichrom C1-Inhibitor reagents were used for the spectrophotometric measurement of HMWK activity and activity of the C1-inhibitor. Reference intervals for HMWK and C1-inhibitor are 75%–130% of normal and 80%–125%, respectively.

The C5a and C5b-9 fragments of the complement system were determined by ELISA assay with the Berichrom C5a and Berichrom C5b-9 reagents. Reference intervals for C5a and C5b-9 are 0.15–0.50 ng/ml and 200–400 ng/ml.

Statistical Analysis

Data were expressed as mean values and standard deviations. Differences in continuous variables between survivors and non-survivors were compared with the parametric t-test or the nonparametric Mann-Whitney test. Categorical data were compared by Fisher’s exact test. Sensitivity and specificity of protein C in plasma of patients with generalized peritonitis for the prediction of sepsis severity were determined by the ROC (Receiver Operating Characteristic) curve method, and “cut-off” level was determined with the SPSS program for Windows, version 10.0 (SPSS, Chicago, IL). Sensitivity was defined as a number of non-surviving patients with severe diffuse peritonitis and protein C levels below “cut-off” (test positive) / number of all non-surving-patients. Specificity was defined as the number of surviving patients with severe diffuse peritonitis and protein C levels above “cut-off” (test negative) / number of all surviving patients. The area under the curve (AUC) was calculated and represents a quantitative measure of predictive value of protein C for severe septic complications and outcome in patients with diffuse secondary peritonitis. In all tests, a p value < 0.05 was considered to be statistically significant.

Results

The mean age of patients in the study group was 61.4 years (range: 19–78 years); for those in the control group 56.5 years (range; 24–69 years). Regarding the mean age, presence of risk factors (cardiovascular, pulmonary, liver and renal failure, diabetes mellitus, malignancy), there was no evidence of statistically significant differences between the study group and the control group. Etiology of diffuse peritonitis significantly influenced treatment outcome. Spontaneous peritonitis was predominant (68%), followed by a type of postoperative peritonitis (27.5%) burdened with a high mortality rate (50%). The average value of APACHE II score on admission in the study group was 19.7 ± 3.5 in survivors and 20.4 ± 4.0 in non-survivors (p > 0.05). The hospital mortality rate of 23% (10/44) was lower than the predicted rate (40%). Lethal outcome of all the patients in the study group was caused by acute organ dysfunction or septic shock development. In the control group mortality rate was 0%.

Values of aPTT in the group of survivors remained unchanged, and in non-survivors those values were slightly increased, without significant difference.

In the group treated for diffuse peritonitis, preoperative protein C values were decreased in 55% of the patients, and more severe protein C activity disorders (below 60%) were evidenced in 18%. Preoperatively, mean protein C activity was significantly lower in the patients who developed severe sepsis (acute organ dysfunction, septic shock) in the late course of the disease and who had a lethal outcome than in the patients with severe peritonitis and abdominal sepsis who survived (57.20% vs. 82.95%; p = 0.0001; Table 1). Trends and differences in the mean postoperative protein C activity indicated significance by postoperative day 2 when the values indicated a return to normalization by increased activity in the group of survivors and a further decrease in activity in the group of non-survivors. The difference in protein C levels between the groups was confirmed as statistically significant on days 0, 1, 2, 3, 5, 7, 10, and 14 (p < 0.03) (Table 1). On admission and postoperative day 1, protein C achieved sensitivity and specificity of 80% and 87. 5%, respectively, with a “cut-off” level of 66.0% (Fig. 1). The AUCs for the preoperative and the first postoperative day were 0.917 (SE-0.037) and 0.819 (SE-0.066) respectively (p < 0.001). In the patients of the control group, who had no signs of postoperative infection or sepsis, protein C activity was consistently maintained within the range of normal (Table 1), which eliminated the influence of surgical intervention itself on extensive changes in protein C activity. Differences in protein C levels between the control and study groups over the study period were statistically significant (p < 0.01).
Table 1

Protein C activity (%) levels in patients with severe diffuse peritonitis (study group) and ventral hernia repair (control group).

 

Protein C (%)study group

Protein C (%) control group

Day

Survivors (mean ± SD) (range)

Non-survivors (mean ± SD) (range)

p Value*

(mean ± SD) (range)

0

82.95 ± 16.59 (47–119)

57.20 ± 11.78 (41–73)*

(p-0.0001)

92.5 ± 6.5 (82–104)**

1

81.02 ± 15.90 (45–107)

62.20 ± 12.17 (50–83)*

(p-0.002)

93.6 ± 7.7 (82–107)**

2

75.00 ± 19.71 (49–121)

62.40 ± 14.54 (51–84)*

(p-0.021)

91.5 ± 5.8 (80–118)**

3

86.04 ± 20.17 (54–121)

63.00 ± 14.03 (34–89)*

(p-0.001)

93.1 ± 56.7 (80–110)**

5

83.24 ± 24.6 (53–129)

69.20 ± 16.21 (23–86)*

(p-0.033)

94.7 ± 15.3 (84–119)**

7

81.10 ± 15.23(59–101)

52.50 ± 1.73 (51–54)*

(p-0.002)

92.5 ± 6.1 (82–121)**

10

95.50 ± 13.28 (79–108)

56.00 ± 1.15 (55–57)*

(p-0.006)

96.8 ± 6.7 (80–110)**

14

94.38 ± 17.95 (77-118)

49.70 ± 3.90 (45–53)*

(p-0.0001)

99.2 ± 7.4 (84–120)**

Values presented as mean ± standard deviation (S.D.).

*Statistically significant difference between survivors and non-surviviors; p < 0.03.

**Statistically significant difference between study group and control group; p < 0.01.

https://static-content.springer.com/image/art%3A10.1007%2Fs00268-005-7771-7/MediaObjects/268_2005_7771_f1.jpg
Figure 1

Receiver-operator-characteristic (ROC) curve: protein C sensitivity (80%) and specificity (87.5%) preoperatively in patients with diffuse peritonitis for the prediction of severe septic complications and outcome; “cut-off” level of protein C activity—66.0%. (*AUC-0.917; **SE-0.037; p < 0.001). *AUC: area under the curve; **SE: standard error.

Another coagulation inhibitor, AT III is presented in Table 2. The AT III levels were slightly decreased preoperatively in survivors and during the whole study period in non-survivors. On days 3, 5, 7, 10, and 14 AT III mean activity in survivors and non-survivors became significantly different.
Table 2

Parameters of coagulation cascade: antithrombin III, and activated partial thromboplastin time(aPTT) in survivors and non-survivors among patients with severe diffuse peritonitis.

Day

Antithrombin III

aPTT (s)

 

Survivors

Non-survivors

Survivors

Non-survivors

0

83.74 ± 19.89

61.20 ± 19.83

34.01 ± 5.81

37.40 ± 9.48

1

86.29 ± 21.44

78.00 ± 14.16

35.49 ± 6.21

35.42 ± 5.30

2

80.24 ± 22.92

68.80 ± 9.69

35.39 ± 5.66

38.80 ± 6.60

3

87.72 ± 18.42

61.20 ± 9.48*

35.15 ± 8.18

38.02 ± 4.30

5

88.82 ± 18.84

62.20 ± 12.67*

35.21 ± 9.38

38.14 ± 8.39

7

91.50 ± 15.05

66.00 ± 13.86*

37.09 ± 9.94

41.07 ± 9.29

10

101.25 ± 11.60

76.00 ± 1.62*

36.10 ± 8.23

40.45 ± 13.65

14

96.74 ± 17.40

66.86 ± 6.60*

34.87 ± 5.68

40.99 ± 9.60

Values presented as mean ± standard deviation

*Statistically significant difference between survivors and non-surviviors; p < 0.05.

The parameters of the fibrinolytic cascade—plasminogen and α2-antiplasmin, and PAI-1 and D-dimer—are presented in Table 3. Plasminogen levels were within the range of normal in the group of survivors, and they were decreased on days 0, 1, 3, 5, 7, 10, and 14 in non-survivors. Except on day 2, the difference of plasminogen activity between survivors and non-survivors reached statistical significance. Activity of α2-antiplasmin in survivors remained unchanged, whereas in non-survivors it was slightly decreased on day 3, with a further progressive decrease on days 7, 10, and 14. The difference between the two groups was statistically significant on days 5, 7, 10, and 14. The PAI-1 levels were high in both groups on days 0, 1, 2, 3, and 5. Survivors showed a trend toward normalization of PAI-1 levels, whereas non-survivors demonstrated a further progressive increase on days 7, 10, and 14. On days 7, 10, and 14 the difference of PAI-1 levels between survivors and non-survivors reached statistical significance. The D-dimer levels were high in the group of non-survivors throughout the study period; however, survivors showed high D-dimer levels on days 0, 1, 2, 3, and 5. D-dimer values on days 7, 10, and 14 were significantly different between survivors and non-survivors.
Table 3

Parameters of the fibrinolysis cascade—plasminogen and α2-antiplasmin Plasminogen activator inhibitor 1(PAI-1) and D-dimer—in surviving and non-surviving patients with severe diffuse peritonitis.

A. Plasminogen and α2-antiplasin

 

Plasminogen (%)

α2-antiplasmin (%)

Day

Survivors

Non-survivors

Survivors

Non-survivors

0

95.08 ± 13.99

70.60 ± 17.39*

96.80 ± 16.34

83.43 ± 25.90

1

94.02 ± 16.97

71.20 ± 19.21*

101.87 ± 16.56

91.00 ± 17.54

2

86.29 ± 17.81

81.00 ± 28.25

90.90 ± 16.93

78.63 ± 19.56

3

93.67 ± 11.20

65.00 ± 8.92*

96.19 ± 12.90

68.28 ± 15.75

5

96.53 ± 20.28

63.60± 18.67*

92.15 ± 15.92

66.80 ± 10.95*

7

95.70 ± 14.65

53.50 ± 7.51*

88.70 ± 12.50

67.00 ± 14.10*

10

99.25 ± 7.87

66.00 ± 4.62*

101.80 ± 12.30

62.00 ± 17.10*

14

96.56 ± 6.45

56.90 ± 3.68*

96.65 ± 16.31

59.95 ± 11.34*

B. PAI-1 and D-dimer

    
 

PAI-1 (U/ml)

D-dimer (μg/l)

Day

Survivors

Non-survivors

Survivors

Non-survivors

0

4.43 ± 1.17

4.49 ± 1.23

636.91 ± 186.32

683.45 ± 258.96

1

4.59 ± 1.28

4.56 ± 0.63

617.38 ± 230.97

713.20 ± 389.30

2

4.36 ± 1.81

4.76 ± 1.67

658.45 ± 269.70

745.68 ± 395.24

3

4.4 ± 1.32

4.48 ± 1.41

692.04 ± 184.99

847.60 ± 349.04

5

3.98 ± 1.41

4.51 ± 1.53

701.35 ± 208.32

889.93 ± 478.27

7

3.82 ± 1.51

5.25 ± 1. 81*

646.42 ± 234.59

873.08 ± 410.52*

10

3.40 ± 1.20

4.92 ± 1.28*

573.96 ± 212.26

1008.27 ± 530.46*

14

3.27 ± 1.06

5.37 ± 1.80*

594.38 ± 170.71

1106.00 ± 540.96*

Values are presented as mean ± standard deviation.

*Statistically significant difference between survivors and non-surviviors; p < 0.05.

The parameters of the kinin-kalikrein cascade, C1-inhibitor and HMWK, are presented in Table 4. C1-inhibitor mean activity was permanently maintained within the normal range in both groups throughout the study period. The difference between survivors and non-survivors was not significant. In survivors, HMWK levels were slightly decreased on days 0, 1, and 2. Survivors showed a trend toward normalization of HMWK levels, whereas non-survivors demonstrated a further progressive decrease on days 5, 7, 10, and 14. On days 5, 10, and 14 the difference in HMWK activity between survivors and non-survivors reached statistical significance.
Table 4

Parameters of the kinin-kalikrein cascade: C1-inhibitor and high molecular weight kininogen (HMWK) in survivors and non-survivors among patients with severe diffuse peritonitis.

 

C1-inhibitor (%)

HMWK (%)

Day

Survivors

Non-survivors

Survivors

Non-survivors

0

118.83 ± 8.85

112.80 ± 125.65

74.82 ± 22.27

65.20 ± 31.123

1

121.04 ± 27.65

120.00 ± 23.96

71.10 ± 23.74

57.78 ± 26.10

2

133.47 ± 20.81

118.00 ± 26.41

72.94 ± 23.80

65.20 ± 23.72

3

125.13 ± 28.10

109.40 ± 11.42

89.35 ± 25.70

57.60 ± 27.25

5

129.69 ± 24.65

108.40 ± 22.14

80.56 ± 25.38

39.60 ± 24.84*

7

135.50 ± 29.29

107.00 ± 36.95

82.80 ± 24.16

50.00 ± 18.41

10

148.33 ± 23.16

107.50 ± 30.60

88.25 ± 21.25

49.50 ± 30.60*

14

139.90 ± 26.44

105.60 ± 35.63

81.60 ± 26.34

47.91 ± 19.70*

Values are presented as mean ± standard deviation.

*Statistically significant difference between survivors and non-survivors; p < 0.05.

C5a and C5b-9 fragments of the complement system are presented in Table 5. C5a levels were increased in both survivors and non-survivors throughout the study period. On day 14, C5a levels became significantly different. C5b-9 levels were high in both groups during the whole study. On days 7, 10, and 14 survivors showed a trend toward normalization, whereas in non-survivors C5b-9 levels were progressively increased. The difference between the two groups was statistically significant on days 5, 7, 10, and 14.
Table 5

Complement fragments C5a and C5b-9 in survivors and non-survivors among patients with severe diffuse peritonitis.

 

C5b-9 complement (ng/ml)

C5-a complement (ng/ml)

Day

Survivors

Non-survivors

Survivors

Non-survivors

0

1469 ± 588.1

1299 ± 544.5

3.78 ± 1.39

2.32 ± 1.44

1

1237 ± 549.2

1424 ± 566.7

3.11 ± 1.93

2.59 ± 1.63

2

1193 ± 375.9

1176 ± 530.7

2.71 ± 1.12

2.12 ± 1.53

3

1041 ± 442.2

1374 ± 600.3

2.49 ± 1.11

2.06 ± 0.76

5

1021 ± 571.6

2111 ± 581.1*

2.20 ± 1.25

3.89 ± 1.83

7

1023 ± 394.5

1860 ± 268.7*

2.50 ± 1.60

2.69 ± 1.57

10

1157 ± 400.4

2730 ± 578.9*

2.55 ± 0.87

4.05 ± 1.34

14

1015 ± 420.5

3240 ± 430.6*

2.21 ± 1.63

4.47 ± 0.97*

Values are presented as mean ± standard deviation.

*Statistically significant difference between survivors and non-survivors; p < 0.05.

Discussion

Diffuse secondary bacterial peritonitis is one of the most common problems in abdominal surgery practice [25]. Despite the introduction of new surgical techniques, progress in management, advances in intensive care, introduction of new antibiotics, and attempts to modulate immune response, mortality of patients with peritonitis remains high [25, 2529]. Abdominal sepsis-related organ failure is the leading cause of death and is associated with overall mortality rates as high as 65% in surgical intensive care units [26].

In the course of intraabdominal infection, the peritoneal cavity represents the initial barrier against bacterial infection. Activated macrophage that initiates activation of numerous plasmatic and cell systems provides a second level of defense. Systemic inflammatory response is developed under the influence of numerous inflammatory reaction mediators. Excessive activity of the induced mediators leads to significant damage to the organism and thus, septic syndrome is justifiably termed “the mediator disease” [19, 21].

The fact that basic events encountered in sepsis take place on the cellular level has drawn attention to diagnosis of early and discrete plasmatic disorders. Accordingly, modern treatment strategies are directed toward blockade of the sepsis mediators. Numerous research attempts within the basic and the clinical disciplines have been aimed at contributing to better understanding of abdominal sepsis and improvement of therapeutic results.

Coagulation activation with subsequent diffuse intravascular deposition of fibrin has been implicated as an etiological factor in multiple organ dysfunction syndrome in patients with sepsis, and in transplant and trauma patients [30]. Numerous studies have demonstrated that depressed protein C concetrations in both pediatric and adult sepsis patients are associated with increased morbidity and mortality [14, 17, 19, 3139].

The PROWESS (Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis) multicenter clinical study, related to the application of recombinant human activated protein C (rhAPC-drotrecogin alpha) in the treatment of sepsis, gave more than encouraging results. Finally, the most important effect of APC application is statistically significant reduction of 28-day mortality in severe sepsis from 30.8% to 24.7% [9, 10, 13, 20].

As for surgical treatment of abdominal sepsis, the question of early diagnosis remains open. Early and reliable diagnosis of severe septic complications is notoriously difficult, and the search for novel approaches to overcome this problem is still a compelling issue for clinicians [26]. Defining sensitive markers of severe sepsis in the abdomen is also important for establishing indications for early relaparotomy. The clinical onset of organic lesions and MODS is accompanied by delayed reintervention [2729].

Our study was conducted as part of an attempt to examine the role and significance of disturbances of plasmatic cascades in the setting of severe, advanced, and neglected diffuse peritonitis, and thus to contribute to improving the diagnosis and prognosis of the diseases that are quite frequent in our population. Preoperatively, the mean protein C activity was significantly lower in the patients with developed severe septic complications—i.e., acute organ dysfunction or septic shock—and lethal outcome in comparison with the patients who survived (57.20% vs. 82.95%; p = 0.0001; Table 1). In the group of survivors, no development of septic shock was recorded. The postoperative interval of 48 hours was critical regarding both the increase and normalization of protein C levels in the group of survivors and the permanent decrease of protein C activity in the patients with developing severe sepsis, septic shock, and lethal outcome. Over the course of the study period, the differences between protein C levels in survivors and non-survivors were consistently statistically significant (p < 0.03). In the group of non-survivors, protein C activity was permanently decreased, preoperatively and postoperatively, below the level of 70.0%. Protein C was of excellent predictive value and achieved sensitivity of 80% and specificity of 87.5% in discriminating survivors from non-survivors within the first 48 hours, with a “cut-off” level of 66.0% (AUC-0.917; SE-0.037; p < 0.001; Fig. 1).

All other analyzed parameters showed disturbances of the plasma proteolytic cascade systems—i.e. coagulation, fibrinolysis, kinin-kalikrein cascade, and complement system—during severe peritonitis associated with sepsis syndrome. All evaluated parameters were significantly different between survivors and non-survivors, as well as between the study and control groups (p < 0.05). Non-survivors had significantly lower levels of AT III plasminogen, and α2-antiplasmin, and higher concentrations of PAI-1 and D-dimer than survivors (Tables 2 and 3). The HMWK levels were decreased, while levels of C5-a and C5b-9 complement were increased in non-survivors, with significant difference from survivors (Tables 4 and 5). All differences were significant in the late phase of the disease— i.e., on days 7, 10, and 14.

In contrast to other analyzed paremeters of plasmatic cascade systems during inflammation, depressed protein C activity levels in non-survivors were significantly different from the levels in survivors at every point of time. This factor constantly correlated with abdominal sepsis severity and outcome, especially in the early phase of the disease, suggesting that an ongoing hypercoagulable state exists even before clinical symptoms of sepsis occur. Compared with other biochemical parameters, protein C significantly contributes to earlier and better stratification of patients with risk of severe septic complications during the course of diffuse peritonitis, and it provides excellent predictive assessment in severe abdominal infection and inflammation. In the control group, protein C activity was maintained within the range of normal. Difference in average protein C values between the study and control groups remained significant throughout the study period (p < 0.01) (Table 1). The above-mentioned results indicate the importance of protein C as a significant biological marker of coagulation disorders and inflammatory cascade in abdominal sepsis. The data also suggest that protein C activity could be a very early and sensitive predictor of severe septic complications in patients with diffuse secondary peritonitis.

Because no analyses of protein C activity in peritonitis and abdominal sepsis have been published so far, our results, can only be compared with the results of familiar studies concerning sepsis of non-abdominal origin, and they are in accord with those previously published data [14, 17, 19, 3139]. From a diagnostic point of view, the interval between laboratory detection of the plasmatic disorders and their complete clinical manifestation is of the utmost importance [40]. The results of Mesters et al. [14] and Macias and Nelson [31], as well as our own, clearly demonstrate coagulation cascade activation and disturbances of protein C activity before the appearance of severe sepsis and septic shock.

Protein C deficiency certainly plays an important role in these disturbances, and appearance of low protein C activity levels (66% and lower) at early stage of severe diffuse peritonitis clearly leads to development of severe systemic septic complications i.e. acute organ dysfunction or septic shock, as well as to a high risk of lethal outcome. Thus protein C determination can help to identify patients at risk of this complization, raising the possibility that APC resuscitation at the right time could be a beneficial means of treating these patients.

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© Société Internationale de Chirurgie 2005