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Keywords:

  • Coagulopathy;
  • Sepsis;
  • Septic shock

Abstract

  1. Top of page
  2. Abstract
  3. Materials and Methods
  4. Results
  5. Discussion
  6. Footnotes
  7. Acknowledgments
  8. References

Background: Coagulopathy is a potentially underrecognized complication of sepsis and septic shock in critically ill neonatal foals.

Hypothesis: Critically ill neonatal foals have abnormalities in coagulation that are associated with disease severity and outcome.

Animals: Foals <72 hours old admitted to a neonatal intensive care unit.

Methods: Prospective, observational study. Blood was collected at admission, 24, and 48 hours for platelet count, prothrombin time, activated partial thromboplastin time, antithrombin activity and concentrations of fibrin degradation products, and fibrinogen in plasma from all foals.

Results: Sixty-three foals were enrolled and classified as Septic Shock (12), Septic (28), and Other (23). At least 1 abnormal value was found in 18/28 (64%) samples from the Septic Shock group, 66/85 (78%) from the Septic group, and 30/59 (51%) from the Other group (P= .01). Coagulopathy (3 or more abnormal values) was present in 7/28 (25%) samples in the Septic Shock group, 14/85 (16%) samples in the Septic group, and 3/59 (5%) samples in the Other group (P= .0028). Clinically detectable bleeding occurred in 8/12 (67%) Septic Shock cases, 11/28 (39%) Septic cases, and 3/23 (13%) Other cases (P= .009). Foals in Septic Shock were 12.7 times more likely to have clinical evidence of bleeding than those in the Other group (95% CI 2.3–70, P= .004). Treatment with fluids or plasma did not have a detectable effect on coagulation values.

Conclusions and Clinical Importance: Coagulopathy commonly occurs in critically ill neonatal foals, especially those with sepsis and septic shock.

Despite advances in medical therapy, neonatal foals with sepsis continue to have higher morbidity and mortality rates compared with foals with other disease syndromes treated in Neonatal Intensive Care Units (NICUs).1–5 The association of sepsis, inflammation, coagulation derangement, and suppressed fibrinolysis is documented in veterinary and human patients.1,6

Although perinatal coagulopathy has been associated with neonatal infections, changes in hemostatic function associated with severe disease in critically ill neonatal foals are incompletely documented.1,5,10,11 However, coagulopathy is a major contributor to morbidity and mortality associated with a need for intensive care in human infants, particularly those with sepsis and septic shock.6–8,12,13 Coagulopathy can range from laboratory abnormalities with no clinical evidence of clotting abnormalities to fulminant disseminated intravascular coagulation.9, 14–16

Hemostatic and fibrinolytic indices for normal foals have been previously reported.1,17 Healthy foals have prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT), combined with decreased protein C, antithrombin activity (AT), and fibrinogen concentration compared with adults, similar to differences in coagulation between neonatal and adult human patients.14,16,18

Foals with presumed septicemia have prolonged PT, aPTT, and increased concentration of FDPs with decreased AT and protein C concentration, but platelet and fibrinogen concentrations are not indicative of consumptive coagulopathy.1 Severe thrombocytopenia and coagulopathy occur in foals with bacteremia, sepsis, or both that resolved with directed antimicrobial therapy.10

Coagulopathy is likely an underrecognized complication of many severe neonatal diseases. One recent report describes coagulation differences in septic, nonseptic, and control foals of 4 coagulation parameters.19 Our hypothesis is that critically ill neonatal foals frequently have abnormalities in 6 commonly measured coagulation parameters and these abnormalities are associated with disease severity and outcome. The objective of this study was to describe coagulation parameters in 3 groups of critically ill neonatal foals at admission (those with septic shock, sepsis, and other conditions), assess these parameters over the 1st 2 days of hospitalization, and investigate associations with disease severity and outcome.

Materials and Methods

  1. Top of page
  2. Abstract
  3. Materials and Methods
  4. Results
  5. Discussion
  6. Footnotes
  7. Acknowledgments
  8. References

Foals admitted between April 2003 and May 2004 to the NICU Service at the George D. Widener Hospital for Large Animals, University of Pennsylvania, were <72 hours of age at admission and, where informed consent was obtained (approximately 90% of qualified admissions), were prospectively enrolled in the study. This study was performed with approval by the University of Pennsylvania Institutional Animal Care and Use Committee.

Blood was collected at the time of admission (Sample 1), between 12–24 hours (Sample 2), and 24 hours after the 2nd sample (Sample 3) from each foal for platelet count, PT, aPTT, fibrin degradation products (FDP), fibrinogen concentration, and AT. Blood was collected at the time of placement of a cathetera at admission for Sample 1 and by direct venipuncture for Samples 2 and 3. Blood was collected in tubes containing 3.8% buffered sodium citrateb and processed within 15 minutes to obtain an automated platelet count. Samples with reported low platelet counts were also counted manually. Plasma was obtained by centrifugation of samples at 1,240 ×g and frozen at −70 °C within 30 minutes for further testing. Plasma fibrinogen concentration and PT were obtained on thawed plasma samples by an automated analyzerc with lyophilized rabbit brain calcium thromboplastin. Recalcified plasma was incubated with rabbit brain phospholipid and activator to obtain aPTT.c An automated analyzer measured AT by chromogenic assay, also on previously frozen plasma.c Blood was collected in Bothrops atrox venom with soybean trypsin inhibitor tubes for the measurement of FDP concentrations and frozen for further testingd by a slide latex-agglutination test with results reported as either <10, 10–40, or >40 μg/mL.e Blood culture samples were collected at admission as follows: the area over the left or right jugular vein was clipped and aseptically prepared using a 5-minute chlorhexidine scrub followed by wiping with 70% alcohol. Sterile latex gloves and standard masks were worn and a 16 g, over-the-wire IV cathetera was placed using the Seldinger technique. Seven milliliters of blood were aseptically collected through the IV catheter into a sterile syringe, a sterile needle was placed on the syringe, and the blood was aseptically introduced into 70 mL of trypticase soy brothf enriched with carbon dioxide, and containing sodium polyanethol sulfonate as an anticoagulant. The broth was then incubated at 35 °C for up to 10 days. Additional routine hematologic and clinicopathologic testing was performed at the time of admission and during the 1st 48 hours of hospitalization.

Classification of Foals

Foals were categorized into 1 of 3 groups based on clinical data obtained within the 1st 48 hours of hospitalization using conventional definition.20–22 Foals were designated as “Septic” if they were leukopenic (<4,000 cells/μL), had a left shift (presence of band neutrophil cells), had bacteremia or clinical evidence of a septic focus during the 1st 48 hours of hospitalization. Foals were designated as “Septic Shock” if they qualified as septic and showed signs of cardiovascular shock, which required inotrope, pressor, or combined therapy in addition to fluid resuscitation. All the remaining foals were designated as “Other.” Outcome was defined as survival to discharge (Survivors) or death/euthanasia before discharge (Nonsurvivors).

Available healthy foals (born to high-risk pregnant mares or admitted as a companion to an ill mare) were utilized to establish age-matched normal values in our laboratory. An abnormal coagulation value was defined as a value outside of 2 standard deviations of the mean value of the healthy foal group.1 If 3 or more values were out of the reference range at any sample period, the foal was classified as having coagulopathy during that period.

A physical examination was performed on each foal at least twice daily by 1 or more of the authors. Clinical evidence of bleeding including epistaxis, petechiae, ecchymoses, and bleeding for more than 10 minutes after venipuncture in the 1st 48 hours of hospitalization was recorded.

Data Analysis

The significance of measures of association between pairs of categorical variables was performed using Pearson's χ2-test and, when category counts were <5, corroborated with the aid of Fisher's exact test. Quantification of the association between outcome (survival, clinical signs of bleeding, occurrence of coagulopathy) and exposure (eg septic shock, shock, other, occurrence of bacteremia, therapy) was assessed by logistic regression. Clustered regression was used to ease the assumption of data independence when repeated observations were involved. When category counts are low, the P-values from logistic regression were corroborated using Fisher's exact test.

Kruskal-Wallis and 1-way analysis of variance tests were used to analyze parameters that were continuous. By using a parametric and nonparametric test jointly under all situations, the impact of absence of normality of the data can be discerned. Under situations of contradictory results from these 2 tests, the Kruskal-Wallis test was reported. The type 1 error rate was 5%.

Somers' D-test clustering on case number was used to protect against loss of data independence and explore the impact of allowance for repeated measures.

When multiple comparisons were conducted in association with outcomes, Bonferroni's correction was appliedg to maintain our required type 1 error rate.

Results

  1. Top of page
  2. Abstract
  3. Materials and Methods
  4. Results
  5. Discussion
  6. Footnotes
  7. Acknowledgments
  8. References

The study included 63 foals: 12 categorized as Septic Shock (19%); 28 as Septic (44%); and 23 with Other problems (37%). The primary problems of the Other group included: neonatal encephalopathy (5), dystocia/caesarian section (4), placentitis/premature placental separation (4), contracture (3), hemorrhage (2), colic (2), meconium impaction (1), neonatal isoerythrolysis (1), and ruptured bladder (1). Many foals in the Septic and Septic Shock groups had secondary problems. Twelve foals were born in the hospital, 41 were 24 hours old or less at admission, 9 were >24 but <48 hours old, and the final foal was 2.5 days old at admission. The breed distribution reflected the typical NICU population: 36 Thoroughbreds, 16 Standardbreds, 5 Warmbloods, 2 Arabians, 2 ponies, 1 Appaloosa, and 1 Quarter horse. There were 36 colts and 27 fillies.

Five healthy foals (born to high-risk pregnant mares [4] or admitted at 7 hours of age as a companion to an ill mare [1]) were utilized to establish reference values for healthy foals during the 1st 48 hours of life in our laboratory (Table 1).

Table 1.   Coagulation parameters from healthy foals (N = 5).
Age (Hours)PT (Seconds)aPTT (Seconds)AT (%)Platelet Count (× 103/μL)Fibrinogen (mg/dL)FDP
  • a

    Mean ± standard deviation.

  • b

    50th (25th–75th) percentiles.

  • PT, prothrombin time; aPTT, activated partial thromboplastin time; AT, antithrombin; FDP, fibrin degradation products (1 = <10 mg/mL, 2 = 10–40 mg/mL, 3 = >40 mg/mL).

<710.4 ± 0.4a52.8 ± 8.1147.6 ± 15.0381.6 ± 58.9226.4 ± 57.31.2 ± 0.3
10.5 (10.4–10.6)b50.9 (47.9–51.2)152 (144–154)286 (245–325)221 (192–249)1 (1–1)
2410.6 ± 0.951.9 ± 10.0128.5 ± 22.3229 ± 50.8251.0 ± 64.11.2 ± 0.3
10.7 (9.9–11.3)51.3 (43.7–60.1)128 (113–144)231 (205–262)234 (201–301)1 (1–1)
4811.1 ± 1.855.6 ± 10.4133.0 ± 20.7222.2 ± 60.6316.8 ± 42.81 ± 0.0
10.5 (10.0–12.2)57.2 (47.6–63.5)138 (119–147)200 (180–264)321 (280–353)1 (1–1)

One hundred and seventy-one samples were available from the 63 foals. Ten foals were euthanized before all samples could be obtained accounting for the 18 missing samples. Eight foals were euthanized after 1 sample was taken (4 in the Septic Shock group, 1 in the Septic group, and 3 in the Other group) and 2 were euthanized before the last sample could be obtained (1 in the Septic Shock group and 1 in the Other group). When all sample periods were combined (Table 2), there were significant differences in coagulation values between groups. There was a difference between the Septic and Other (P < .001) but not the Septic Shock and Other or Septic and Septic Shock for PT. There was a difference between Septic and Other (P= .001) and Septic Shock and Other (P < .001) but not Septic and Septic Shock for AT. There was a difference between Septic and Other (P= .009) but not Septic Shock and Septic or Septic Shock and Other for fibrinogen concentration. There were no significant differences between groups for aPTT, FDP, or platelet count.

Table 2.   Coagulation values of foals for all sample periods by condition, blood culture status, outcome, and therapy.
ConditionPT (Seconds)aPTT (Seconds)AT (%)Platelet Count (× 103/μL)Fibrinogen (mg/dL)FDP
  1. PT, prothrombin time, 50th (25th–75th) percentiles; APTT, activated partial thromboplastin time, 50th (25th–75th) percentiles; AT, antithrombin, 50th (25th–75th) percentiles; platelet count 50th (25th–75th) percentiles; fibrinogen mg/dL, 50th (25th–75th) percentiles; FDP, fibrin degradation products (1 = <10 mg/mL, 2 = 10–40 mg/mL, 3 = >40 mg/mL) 50th (25th–75th) percentiles; FFP, frozen plasma ≤ 6 months old; not FFP, frozen plasma > 6 months old.

Septic shock (N = 12)11.6 (11.1–13.0)58.0 (51.7–70.4)113 (100–124)190 (140–220)292 (246–368)1 (1–1)
Sepsis (N = 28)11.8 (11.0–12.6)61.8 (52.0–69.7)120 (104–133)210 (170–230)367 (289–499)1 (1–2)
Other (N = 23)10.9 (10.3–11.3)53.9 (48.1–62.7)129 (120–152)210 (190–250)291 (239–373)1 (1–2)
Blood culture status
 Positive (N = 12)11.8 (11.0–13.4)66.0 (53.9–86.8)117 (90–127)200 (170–240)318 (252–476)1 (1–2)
 Negative (N = 51)11.3 (10.7–12.2)56.2 (49.6–67.1)124 (110–138)210 (170–240)342 (243–423)1 (1–2)
Outcome
 Nonsurvivors (N = 20)11.7 (11.1–12.5)58.2 (52.0–74.3)112 (94–123)180 (150–230)318 (217–397)1 (1–2)
 Survivors (N = 43)11.2 (10.7–12.2)57.2 (49.5–67.5)126 (114–139)210 (190–240)346 (270–437)1 (1–2)
Therapy
 IV fluids (N = 43)11.4 (10.9–12.4)59.5 (51.5–69.7)121 (108–130)210 (170–240)326 (243–411)1 (1–2)
 No IV fluids (N = 20)11.4 (10.3–11.8)50.8 (45.1–58.9)132 (120–148)210 (180–240)332 (273–410)1 (1–2)
 Plasma (N = 40)11.5 (10.9–12.5)58.7 (51.4–68.4)122 (107–133)200 (170–240)342 (245–442)1.4 ± 0.6
 No plasma (N = 23)11.1 (10.3–11.6)55.0 (47.6–66.0)128 (114–138)210 (190–240)328 (246–379)1 (1–2)
 FFP (N = 19)11.4 (10.9–12.7)61.7 (54.2–70.5)118 (104–132)200 (140–240)350 (243–513)1 (1–2)
 Not FFP (N = 16)11.6 (11.0–12.4)52.5 (48.0–61.9)122 (108–142)210 (180–230)331 (252–388)1 (1–2)

When the coagulation results were compared during each sample period there were fewer significant differences between groups (Tables 3–5). No significant differences were found in coagulation parameters between groups at sample period 1 (admission). PT during sample period 2 were significantly different between Septic and Other (P= .003) but not Septic Shock and Other or Septic and Septic Shock.

Table 3.   Coagulation values of foals for the admission sample by condition, blood culture status, outcome, and therapy.
ConditionPT (Seconds)aPTT (Seconds)AT (%)Platelet Count (× 103/μL)Fibrinogen (mg/dL)FDP
  1. PT, prothrombin time, 50th (25th–75th) percentiles; aPTT, activated partial thromboplastin time; 50th (25th–75th) percentiles; AT, antithrombin, 50th (25th–75th) percentiles; platelet count, 50th (25th–75th) percentiles; fibrinogen mg/dL, 50th (25th–75th) percentiles; FDP, fibrin degradation products (1 = <10 mg/mL, 2 = 10–40 mg/mL, 3 = >40 mg/mL) 50th (25th–75th) percentiles; FFP, frozen plasma ≤ 6 months old; not FFP, frozen plasma > 6 months old.

Septic shock (N = 12)11.5 (11.2–13.8)70.1 (52.5–93.2)112 (100–124)190 (140–240)318 (234–388)1 (1–1)
Sepsis (N = 28)11.6 (10.9–12.6)61.9 (50.2–69.3)121 (104–135)200 (160–220)375 (296–495)2 (1–2)
Other (N = 23)11.0 (10.2–11.5)55.6 (49.1–65.4)124 (118–142)210 (170–260)294 (240–356)1 (1–2)
Blood culture status
 Positive (N = 12)11.5 (11.1–13.0)64.8 (51.5–93.2)115 (96–128)210 (170–240)313 (270–447)1 (1–2)
 Negative (N = 51)11.4 (10.7 –12.2)56.9 (49.6–68.4)124 (112–138)200 (170–240)328 (241–425)1 (1–2)
Outcome
 Nonsurvivors (N = 20)11.5 (11.2–12.8)66.0 (53.9–84.8)112 (92–124)180 (140–240)311 (198–379)1 (1–2)
 Survivors (N = 43)11.4 (10.7–12.3)57.6 (48.7–67.5)126 (114–138)210 (190–260)342 (273–441)1 (1–2)
Therapy
 IV fluids (N = 43)11.5 (10.9–12.4)63.0 (51.5–70.2)119 (104–130)210 (170–240)319 (241–389)1 (1–2)
 No IV fluids (N = 20)11.4 (10.2–11.5)49.0 (43.1–56.1)135 (112–145)200 (150–230)319 (282–416)1 (1–2)
 Plasma (N = 40)11.5 (11.0–12.5)61.8 (51.5–67.5)120 (102–134)200 (170–240)328 (242–437)1 (1–2)
 No plasma (N = 23)11.2 (10.2–11.6)54.3 (47.4–70.2)126 (114–136)200 (170–240)319 (234–375)1 (1–2)
 FFP (N = 19)11.4 (11.0–12.6)64.2 (54.8–71.7)115 (100–130)200 (160–240)3356 (243–524)1 (1–2)
 Not FFP (N = 16)11.7 (11.2–12.4)52.5 (48.1–63.6)118 (107–138)210 (190–240)314 (240–387)1 (1–2)
Table 4.   Coagulation values of foals 24 hours after admission by condition, blood culture status, outcome, and therapy.
ConditionPT (Seconds)aPTT (Seconds)AT (%)Platelet Count (× 103/μL)Fibrinogen (mg/dL)FDP
  • a

    4 foals were euthanized before sample 2.

  • b

    b 1 foal was euthanized before sample 2.

  • c

    c 3 foals were euthanized before sample 2.

  • d

    d 3 foals were euthanized before sample 2.

  • e

    e 5 foals were euthanized before sample 2.

  • f

    f 8 foals were euthanized before sample 2.

  • g

    g 6 foals were euthanized before sample 2.

  • h

    h 2 foals were euthanized before sample 2.

  • i

    i 5 foals were euthanized before sample 2.

  • j

    j 3 foals were euthanized before sample 2.

  • k

    k 1 foal was euthanized before sample 2.

  • l

    l 2 foals were euthanized before sample 2.

  • PT, prothrombin time, 50th (25th–75th) percentiles; aPTT, activated partial thromboplastin time; 50th (25th–75th) percentiles; AT antithrombin, 50th (25th–75th) percentiles; platelet count, 50th (25th–75th) percentiles; fibrinogen mg/dL, 50th (25th–75th) percentiles; FDP, fibrin degradation products (1 = <10 mg/mL, 2 = 10–40 mg/mL, 3 = >40 mg/mL) 50th (25th–75th) percentiles; FFP, frozen plasma ≤ 6 months old; not FFP, frozen plasma > 6 months old.

Septic shock (N = 8)a11.8 (11.6–12.9)55.6 (53.2–65.0)110 (90–119)180 (140–230)271 (252–300)1 (1–1)
Sepsis (N = 27)b12.0 (11.6–12.8)62.6 (55.1–70.9)117 (103–128)210 (170–220)383 (273–534)1 (1–2)
Other (N = 20)c11.0 (10.4–11.2)51.1 (46.5–59.2)130 (116–150)220 (190–250)271 (231–373)1 (1–2)
Blood culture status
Positive (N = 9)d11.8 (11.6–12.9)63.8 (55.5–79.0)114 (80–124)180 (170–210)330 (252–416)1 (1–1)
Negative (N = 46)e11.5 (11.0–12.2)55.6 (48.5–66.6)122 (108–132)210 (190–240)342 (241–446)1 (1–2)
Outcome
Nonsurvivors (N = 12)f11.8 (11.4–12.4)56.2 (50.6–77.7)106 (86–116)180 (160–230)369 (252–411)1 (1–2)
Survivors (N = 43)11.3 (10.9–12.2)56.0 (48.9–68.2)124 (112–136)210 (180–240)355 (270–446)1 (1–2)
Therapy
IV fluids (N = 37)g11.6 (11.0–12.4)57.2 (53.2–70.4)116 (106–128)210 (170–230)355 (266–416)1 (1–2)
No IV fluids (N = 18)h11.6 (10.9–12.2)52.7 (46.3–59.2)130 (114–144)220 (190–140)288 (212–361)1 (1–2)
Plasma (N = 35)i11.8 (11.1–12.7)58.2 (53.2–70.4)117 (108–129)210 (170–240)356 (252–501)1 (1–2)
No plasma (N = 20)j11.1 (10.3–12.1)54.8 (46.3–64.0)127 (108–132)210 (190–240)288 (215–359)1 (1–2)
FFP (N = 18)k11.8 (11.0–12.9)59.5 (54.2–76.5)116 (108–130)200 (140–240)395 (232–531)1 (1–2)
Not FFP (N = 14)l11.7 (11.1–12.4)54.0 (48.9–67.4)122 (108–140)210 (190–220)341 (266–387)1 (1–2)
Table 5.   Coagulation values of foals 48 hours after admission by condition, blood culture status, outcome, and therapy.
ConditionPT (Seconds)aPTT (Seconds)AT (%)Platelet Count (× 103/μL)Fibrinogen (mg/dL)FDP
  • a

    5 foals were euthanized before sample 2.

  • b

    b 1 foal was euthanized before sample 2.

  • c

    c 4 foals were euthanized before sample 2.

  • d

    d 4 foals were euthanized before sample 2.

  • e

    e 6 foals were euthanized before sample 2.

  • f

    f 10 foals were euthanized before sample 2.

  • g

    g 8 foals were euthanized before sample 2.

  • h

    h 2 foals were euthanized before sample 2.

  • i

    i 6 foals were euthanized before sample 2.

  • j

    j 4 foals were euthanized before sample 2.

  • k

    k 1 foal was euthanized before sample 2.

  • l

    l 3 foals were euthanized before sample 2.

  • PT, prothrombin time, 50th (25th–75th) percentiles; aPTT, activated partial thromboplastin time; 50th (25th–75th) percentiles; AT, antithrombin, 50th (25th–75th) percentiles; platelet count, 50th (25th–75th) percentiles; fibrinogen mg/dL, 50th (25th–75th) percentiles; FDP, fibrin degradation products (1 = <10 mg/mL, 2 = 10–40 mg/mL, 3 = >40 mg/mL) 50th (25th–75th) percentiles; FFP, frozen plasma ≤ 6 months old; not FFP, frozen plasma > 6 months old.

Septic shock (N = 7)a11.2 (10.5–12.4)51.7 (39.8–67.1)122 (106–132)180 (120–200)333 (239–411)1 (1–1)
Sepsis (N = 27)b11.5 (10.8–12.9)59.8 (51.8–69.2)122 (104–137)210 (180–230)354 (294–491)2 (1–2)
Other (N = 19)c10.9 (10.3–11.1)55.7 (48.3–62.7)131 (126–160)210 (180–250)302 (245–410)1 (1–2)
Blood culture status
 Positive (N = 8)d12.1 (10.8–16.0)68.5 (55.2–92.0)124 (97–128)200 (180–220)324 (240–494)1 (1–2)
 Negative (N = 45)e11.1 (10.4–11.9)56.7 (50.1–64.6)128 (113–146)210 (170–230)351 (248–414)1 (1–2)
Outcome
 Nonsurvivors (N = 10)f11.7 (10.7–13.1)54.8 (46.6–61.7)118 (106–132)200 (160–230)239 (197–331)1 (1–2)
 Survivors (N = 43)11.0 (10.4–11.6)57.2 (50.5–67.4)128 (120–146)210 (180–240)346 (250–426)1 (1–2)
Therapy
 IV fluids (N = 35)g11.1 (10.8–12.0)56.2 (50.6–67.4)126 (112–136)210 (170–240)328 (246–411)1 (1–2)
 No IV fluids (N = 18)h10.8 (10.3–12.3)55.2 (42.6–58.6)137 (120–160)210 (190–220)348 (298–410)1 (1–2)
 Plasma (N = 34)i11.2 (10.5–12.3)58.2 (50.0–68.6)126 (109–134)200 (170–230)346 (247–414)1 (1–2)
 No plasma (N = 19)j11.0 (10.4–11.4)55.6 (51.2–63.1)128 (120–146)210 (200–240)339 (273–426)1 (1–2)
 FFP (N = 18)k11.1 (10.5–12.2)60.2 (51.7–67.7)123 (106–132)200 (140–240)324 (243–416)1 (1–2)
 Not FFP (N = 13)l11.3 (10.9–12.2)49.5 (42.6–58.6)130 (118–156)210 (180–230)353 (262–410)1 (1–1)

Coagulation values were considered abnormal if they were more than 2 standard deviations from the mean values for the corresponding sample period of the healthy foals tested (Table 1). With this definition at least 1 parameter was abnormal in 113 (66%) of the 171 samples. There were 18 (64%) of 28 samples with at least 1 abnormal value in the Septic Shock group, 66 (78%) of 85 samples with at least 1 abnormal value in the Septic group, and 30 (51%) of 59 samples with at least 1 abnormal value in the Other group. The number of samples with abnormal values were as follows: Septic Shock—10 foals with no abnormal values, 8 with 1, 3 with 2, 6 with 3, and 1 with 4 abnormal values; Septic—19 foals with no abnormal values, 37 with 1, 15 with 2, 11 with 3, and 3 with 4 abnormal values; Other—29 foals with no abnormal values, 23 with 1, 4 with 2, 3 with 3, and none with 4 abnormal values. The number of abnormal parameter values per sampling period was significantly different between the groups (P= .01). Coagulopathy was present in 7 (25%) of 28 samples in the Septic Shock group, 14 (16%) of 85 samples in the Septic group, and 3 (5%) of 59 samples in the Other group. The number of samples meeting the criteria defining coagulopathy was significantly different between the groups (P= .01). When considering each sample period separately, there were no significant differences between groups for the number of abnormal tests or the occurrence of coagulopathy. The clinical manifestation of coagulopathy, bleeding, was significantly associated with the foal's group with 8 (67%) of 12 Septic Shock foals bleeding, 11 (39%) of 28 Septic foals bleeding, and only 3 (13%) of 23 Other foals bleeding (P= .009). Foals in the Septic Shock group were 12.7 times more likely to have clinical signs of bleeding than were foals in the Other group (P= .004, 95% CI 2.3–70).

Coagulation parameter values were compared between foals with and without bacteremia (N = 12, 51, respectively). When all samples were combined (Table 2), foals with bacteremia had prolonged aPTT (P= .002). When considering each sample period separately (Tables 3–5) there was a significant association of blood culture positive status and increased number of abnormal tests (P= .001) and the presence of coagulopathy (P= .009) for sample period 3 only. Foals with bacteremia were not significantly more likely to show clinical bleeding (P= .081).

Coagulation parameter values were compared between surviving (N = 43) and nonsurviving (N = 20) foals. When all samples were combined (Table 2), nonsurvivors had prolonged PT (P= .004) and lower AT (P= .001). For sample 3 (Table 5) PT was significantly prolonged for nonsurvivors (P= .004).

The effect of fluid and plasma therapy was examined. All foals in the Septic Shock group (12/12) received fluids and 10 received plasma, 18 of the 28 foals in the Septic group received fluids and 16 received plasma, and 13 of the 23 foals in the Other group received fluids and 11 received plasma. Foals receiving IV fluid therapy (N = 43), foals receiving plasma (N = 40), and foals receiving plasma stored <6 months (N = 19) had no significant differences in coagulation parameters from those which did not.

Discussion

  1. Top of page
  2. Abstract
  3. Materials and Methods
  4. Results
  5. Discussion
  6. Footnotes
  7. Acknowledgments
  8. References

In this population of sick foals, abnormal coagulation values were common no matter what the foal's presenting primary problem, with 66% of samples having at least 1 value outside the reference range. However, values were more extreme and more frequently outside the normal range in foals with sepsis and septic shock. This is expected as activation of coagulation and downregulation of anticoagulation systems is an important part of the inflammatory response.23–25 Differences between the groups were most evident when the number of tests outside the normal range was compared. Coagulopathy (3 or more abnormal test results) was evident in 25% of samples in the Septic Shock group, 16% of samples from the Septic group, and only 5% of the Other group. Also, as expected, because of the differences in the severity of the inflammatory response, clinical evidence of bleeding was significantly different between groups, being found in 67% of Septic Shock foals and 39% of Septic foals but only 13% of Other foals. An unexpected finding that remains unexplained is that while foals in the Septic Shock group were more likely to have 3 or more abnormal values, the frequency of at least 1 abnormal coagulation parameter value occurred more often in the Septic group. Also, the PT values during sample period 2 were significantly different between the Septic group and the Other group but not between the Septic Shock group and the Other group. It is possible that septic shock develops in foals when their inflammatory response is unable to respond appropriately to confine the infection. The finding of multiple coagulation parameter abnormalities could reflect that failure whereas the finding of single, transient abnormalities may reflect activation of the defenses.

Bacteremia was also associated with coagulation abnormalities, reinforcing the connection between sepsis and coagulopathy. Foals with bacteremia were more likely to have abnormal coagulation parameters and coagulopathy. It has been proposed that the coagulation system is an important part of the host's defense against bacterial pathogens and, at the same time, many pathogenic bacteria manipulate the coagulation system to aid in their successful invasion of the host.26,27 The finding of significantly more foals with coagulopathy at the last sampling period is consistent with the development of coagulation abnormalities as the host's response to the bacteremia progresses.

In our study population, foals which did not survive were also more likely to have prolonged PT and lower AT. Foals with fatal outcomes more frequently had coagulopathy and clinical bleeding but neither reached the level of significance. The association of low AT and poor outcome has also been noted in neonatal sepsis in humans, where it was found to predict bacterial infection as well as prognosis.28 In general, AT levels are low and associated with the degree of organ failure in adult human intensive care patients but are not predictive of fatal outcome in these patients.24,29

In our study population, foals treated with fluids and those treated with plasma had no significant differences in coagulation parameters. These therapies, including administration of frozen plasma stored <6 months, did not significantly affect coagulation parameters. Similar findings in humans have led to the current recommendations of not treating patients with abnormal coagulation values with fresh frozen plasma in severe sepsis and septic shock, unless significant bleeding is present.22 Because our study design did not coordinate sampling with administration of plasma, there could have been small transient changes that were not detected.

Although hypofibrinogenemia is often seen in people with coagulopathy, it is not commonly noted in horses due to the unique, exuberant inflammatory response in the horse, usually causing hyperfibrinogenemia.1,30,31 The lack of a fibrinogen response may reflect either a failure of appropriate fibrinogen production or consumption in critically ill neonatal foals. It is interesting to note that in our study, foals with the most severe inflammatory response, septic shock, did not have a significant increase of fibrinogen concentration compared with foals without sepsis (Other group), yet there was a significant increase in the Septic group. Failure to respond to severe inflammation with the expected increase in fibrinogen in these most critically ill neonatal foals is similar to findings in previous studies performed in adult horses,30,31 but this finding may only apply to foals in the 1st week of life. This difference in response of foals in these 2 groups requires further study.

Two serious limitations of our study should be acknowledged. First, our control group from which we established our normal range was small. When designing the study we had anticipated the availability of more normal foals. The variation between laboratories necessitates laboratory specific controls. Our control values are consistent with previously published normal values. Our mean values for samples 1 and 2 (foals <24 hours) are well within a standard deviation of the means for normal foals <24 hours old with the exception of fibrinogen values.1,17 The difference in fibrinogen values is likely due to different assay techniques. The 2nd limitation is the bias, which may have been introduced by grouping all samples together. The 18 missing samples from 10 foals would result in the underrepresentation of these foals in the comparisons. Also, if there are significant changes in normal values between time periods, grouping all of the time periods together may result in a bias.

It is evident from our study that the coagulation cascade, as a component of the inflammatory response, is dynamic. Taking multiple samples during the acute phase of sepsis or septic shock is useful in identifying coagulation abnormalities and the occurrence of a coagulopathy. Full understanding of the true implications of the abnormalities awaits further study.

Footnotes

  1. Top of page
  2. Abstract
  3. Materials and Methods
  4. Results
  5. Discussion
  6. Footnotes
  7. Acknowledgments
  8. References

aArrow International Inc, Reading, PA

bVacutainer, BD Vacutainer, Franklin Lakes, NJ

cACL 6000 Analyzer, Instrumentation Laboratories, Lexington, MA

dFDP tubes, BD Vacutainer, Plymouth, UK

eThrombo-Wellcotest, Murex Laboratories, Norcross, GA

fBBL Septi-Chek, BD Diagnostics, Sparks, MD

gStata/IC 10.1 for Windows, StataCorp LP, College Station, TX

Acknowledgments

  1. Top of page
  2. Abstract
  3. Materials and Methods
  4. Results
  5. Discussion
  6. Footnotes
  7. Acknowledgments
  8. References

This study was funded in part by The International Arabian Horse Association, Region 15. We acknowledge the assistance of Georgianna Sheridan, BVSc, in data collection.

References

  1. Top of page
  2. Abstract
  3. Materials and Methods
  4. Results
  5. Discussion
  6. Footnotes
  7. Acknowledgments
  8. References
  • 1
    Barton MH, Morris DD, Norton N, Prasse KW. Hemostatic and fibrinolytic indices in neonatal foals with presumed septicemia. J Vet Intern Med 1998;12:2635.
  • 2
    McKenzie III HC, Furr MO. Equine neonatal sepsis: The pathophysiology of severe inflammation and infection. Compend Contin Educ Pract Vet 2001;23:661670.
  • 3
    Axon J, Palmer JE, Wilkins PA. Short and long term athletic outcome of neonatal intensive care unit survivors. Proc 45th Conv AAEP 1999;45:224225.
  • 4
    Marsh PS, Palmer JE. Bacterial isolates from blood and their susceptibility patterns in critically ill foals: 543 cases (1991–1998). J Am Vet Med Assoc 2001;218:16081610.
  • 5
    Peek SF, Semrad S, McGuirk SM, et al. Prognostic value of clinicopathologic variables obtained at admission and effect of antiendotoxin plasma on survival in septic and critically ill foals. J Vet Intern Med 2006;20:569574.
  • 6
    Short MA. Linking the sepsis triad of inflammation, coagulation and suppressed fibrinolysis to infants. Adv Neonatal Care 2004;4:258273.
  • 7
    Levi M, Ten Cate H, Van Der Poll T, et al. Pathogenesis of disseminated intravascular coagulation in sepsis. JAMA 1993;270:975979.
  • 8
    Levi M. Disseminated intravascular coagulation: New concepts, new controversies. Hematology 2002;1:335344.
  • 9
    Thomason JD, Calvert CA, Greene CE. The pathophysiology of DIC: When the hemostatic system malfunctions. Vet Med 2005;100:660668.
  • 10
    Bentz AI, Wilkins PA, MacGillivray KC, et al. Thrombocytopenia in two thoroughbred foals with sepsis and neonatal encephalopathy. J Vet Intern Med 2002;16:494497.
  • 11
    Moore LA, Johnson PJ, Bailey KL. Aorto-iliac thrombosis in a foal. Vet Rec 1998;142:459462.
  • 12
    Selim TE, Ghoneim HR, Khashaba MT, et al. Plasma soluble fibrin monomer complex is a useful predictor of disseminated intravascular coagulation in neonatal sepsis. Haematologica 2005;90:419421.
  • 13
    Ramasethu J. Thrombocytopenia in the newborn. Curr Hematol Rep 2004;3:134142.
  • 14
    Aronis S, Platokouki H, Photopoulos S, et al. Indications of coagulation and/or fibrinolytic system activation in healthy and sick very-low-birth-weight neonates. Biol Neonate 1998;74:337344.
  • 15
    Levi M, De Jonge E, Van Der Poll T. Rationale for restoration of physiological anticoagulant pathways in patients with sepsis and disseminated intravascular coagulation. Crit Care Med 2001;S90S93.
  • 16
    Hardaway RM, Williams CH, Vasquez Y. Disseminated intravascular coagulation in sepsis. Semin Thromb Hemost 2001;27:577583.
  • 17
    Barton MH, Morris DD, Crowe N, et al. Hemostatic indices in healthy foals from birth to one month of age. J Vet Diagn Invest 1995;7:380385.
  • 18
    Andrew M, Paes B, Milner R, et al. Development of the human coagulation system in the full-term infant. Blood 1987;70:165172.
  • 19
    Armengou L, Monreal L, Navarro M, Tarancon I, Segura D. Coagulation profile and plasma d-dimer concentration in septic newborn foals. ACVIM Proceedings, Louisville, KY, 2006.
  • 20
    Bone RC, Balk RA, Cerra FB, et al. Definitions for sepsis and organ failure and guidelines for use of innovative therapies in sepsis: The ACCP/SCCM Consensus Conference Committee. Chest 1992;101:16441655.
  • 21
    Abraham E, Matthay MA, Dinarello CA, et al. Consensus conference definitions for sepsis, septic shock, acute lung injury and acute respiratory distress syndrome: Time for a reevaluation. Crit Care Med 2000;28:232235.
  • 22
    Dellinger RP, Levy MM, Carlet JM, et al. Surviving sepsis campaign: International guidelines for management of severe sepsis and septic shock: 2008. Crit Care Med 2008;36:296327.
  • 23
    Schouten M, Wiersinga WJ, Levi M, Van Der Poll T. Inflammation, endothelium, and coagulation in sepsis. J Leukoc Biol 2008;83:536545.
  • 24
    Hofstra JJ, Schouten M, Levi M. Thrombophilia and outcome in severe infection and sepsis. Semin Thromb Hemost 2007;33:604609.
  • 25
    Matsuda N, Hattori Y. Vascular biology in sepsis: Pathophysiological and therapeutic significance of vascular dysfunction. J Smooth Muscle Res 2007;43:117137.
  • 26
    Levi M, Van Der Poll T, Buller HR. Bidirectional relation between inflammation and coagulation. Circulation 2004;109:26982704.
  • 27
    Bergmann S, Hammerschmidt S. Fibrinolysis and host response in bacterial infections. Thromb Haemost 2007;98:512520.
  • 28
    Ersoy B, Nehir H, Altinoz S, et al. Prognostic value of initial antithrombin levels in neonatal sepsis. Indian Pediatr 2007;44:581584.
  • 29
    Sakr Y, Reinhart K, Hagel S, et al. Antithrombin levels, morbidity, and mortality in a surgical intensive care unit. Anesth Analg 2007;105:715723.
  • 30
    Dallap BL, Dolente BA, Boston RC. Coagulation profiles in 27 horses with large colon volvulus. J Vet Emerg Crit Care 2003;13:215225.
  • 31
    Dolente BA, Wilkins PA, Boston RC. Clinicopathologic evidence of disseminated intravascular coagulation in horses with acute colitis. J Am Vet Med Assoc 2002;220:10341038.