Anupam Verma, Akshay Batra, Arvind Kumar Baronia1, Priti Elhence, Afzal Azim1
Departments of Transfusion Medicine and 1Critical Care Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Introduction: Severe sepsis is one of the most common disease processes that are encountered in the ICU.
A systematic evaluation of clinical and laboratory findings is necessary to ascertain the cause and prevalence of hematologic and hemostatic derangement and to determine the correct therapy. However, there is paucity of such data from our region.
Objectives: The aims of the study were: 1) to study the prevalence of various hematologic and hemostatic abnormalities in critically ill patients with severe sepsis and septic shock; 2) to identify alteration in hemostasis in critically ill patients with the help of global coagulation and viscoelastic tests and 3) to study blood transfusion management in these patients.
Materials and Methods: This prospective study was conducted, at a tertiary care hospital for two years which included critically ill adult patients who developed severe sepsis or septic shock during their ICU course. Admission diagnosis, demographic profile, co-morbidities, ICU illness severity scores like APACHE-II, SOFA were noted at admission. Laboratory data collection was done at admission and on daily basis till the end of ICU course including hematological and coagulation parameters for all patients whereas thromboelastography (TEG) was done in selected patients.
Results: Out of 394 admissions in CCM-ICU during our study period, 176 patients met inclusion criteria. Of them, 100 patients were followed; of which 82% received transfusion therapy. Overall 83% of patients were admitted with diseases related to hepatobiliary/pancreatic and respiratory systems. The mean admitting Hb was 9.1 g/dL, with 89% of patients having an admitting Hb <12 g/dL and 68% <10 g/dL. The prevalence of anemia on admission was more common than other hematological abnormalities. Patients who had higher admitting APACHE II and SOFA scores developed septic shock. Mean nadir hemoglobin (Hb) and platelet count were higher in patients with severe sepsis; whereas mean zenith TLC and INR values were higher in patients with septic shock. 89% of patients had admitting Hb less than 12g/dL. 70% had coagulopathy defined by INR more than 1.5. An average of 10 units of red cells, 20 units of plasma, and 5 units of platelets were transfused per patient during ICU stay. An average of 5 transfusion episodes (2 units of red cells, 4 units of plasma and 1 unit of platelets per episode) were given per patient. Four fifth of patients transfused prior to ICU admission had subsequent transfusions during the ICU stay. Transfusion played an important determinant role in patients' characteristics (hematologic and hemostatic) among two subgroups (severe sepsis and septic shock) during their ICU stay. Transfused patients were older, had higher weight, admitting SOFA and APACHE II scores, lower admitting Hb; and longer hospital and ICU length of stay (LOS). Patients with septic shock had higher transfusion rates. Majority of plasma transfusions were done to correct bleeding with/without coagulopathy. Red cell, platelet and plasma transfusions were more in patients who had pretransfusion Hb less than 7.0g/dL, pretransfusion platelet count between 11-50x103/΅L, and pretransfusion INR between 1.51-2.00. Red cell transfusions were more among patients' admitted due to surgical causes. Maximum platelet transfusions were done for therapeutic indication. Plasma transfusions were indicated when there were both bleeding and coagulopathy; more so in patients with septic shock. Forty one patients were categorized on the basis of clot index (CI) into ‘hypocoagulable’, ‘normocoagulable’, and ‘hypercoagulable’; findings of TEG (R time, K time, angle, maximal amplitude, clot index and clot strength) were significantly different among the three categories. Majority of patients were in hypocoagulable state during their ICU stay as depicted by global coagulation tests and TEG. Platelet count correlated with findings of TEG.
Discussion: The present study validates the common occurrence of anemia in critically ill patients and also reports that lower mean Hb levels were associated with higher APACHE II and SOFA scores, longer lengths of stay, and higher mortality rates. Nadir platelet count <150 Χ 103/΅L during ICU course was found in 80% of the present cohort. This is twice than what reported by Arnold et al. and Vanderschueren et al. Coagulopathy, defined as INR >1.5, was identified in 46.0% of patients on admission (mean (SD); 2.20 (.98)). Again, Chakraverty et al. found similar prevalence of coagulopathy in their study (66.0%), A low hematocrit (<25%) was the major identifiable indication in 72% of transfusion events, far greater than 19% of transfusion events reported by Corwin et al. The indications for transfusion in the present study were acute bleeding (65.4%; 246/376) and diminished physiological reserve (32.5%; 122/376). The rate of inappropriate transfusion was 2.1% (8/376). In the present study, transfused patients had higher ICU mortality rates (94.7% vs. 5.3%) and a longer duration of hospital stay (25.3 (20.4) vs 17.1 (13.7) days; p > 0.050), higher APACHE II score, and SOFA score at admission). Also, in the present study, 82% of transfusion episodes were for 2 PRBC units. Most platelet transfusions in our study were given at values 21-50 x 103/΅L. This was different from what Rao et al. reported (50-100 x 103/΅L).
Among critically ill patients in the present study, most platelet transfusions were administered to treat, rather than to prevent, bleeding, with a wide range of transfusion trigger of 7-116 Χ 103/΅L. This was quite opposite to the findings of Arnold et al.,where most platelet transfusions were administered to prevent, rather than to treat, bleeding. This was obvious since 70% of our patients had bleeding (with coagulopathy) more than once during their ICU stay. Nearly one-third of transfusion episodes failed to mount a platelet count increase after a single transfusion in our study; less than that reported by Arnold et al. In the present study, 26% of all FFP transfusions were given in the absence of documented bleeding. This was quite less as reported (43%) in the study by Stanworth et al. Both in the present study and in the study by Holli Halset et al., significant associations were noted between the MA and platelet level on TEG.
Conclusion: The present study shows that the anemia, thrombocytopenia and coagulopathy are common hematologic and hemostatic abnormalities in critically ill patients. The prevalence of anemia on admission was more common than other hematological abnormalities. The patients with septic shock had higher incidence of hematologic and hemostatic abnormalities than the patients with severe sepsis. Majority of patients were in hypocoagulable state during their ICU stay as depicted by global coagulation tests and point-of-care test, TEG.
Further Reading
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2. Arnold DM, Crowther MA, Cook RJ, Sigouin C, Heddle NM, Molnar L, et al. Utilization of platelet transfusions in the intensive care unit: indications, transfusion triggers, and platelet count responses. Transfusion 2006;46:1286-91.
3. Vanderschueren S, De Weerdt A, Malbrain M, Vankersschaever D, Frans E, Wilmer A, et al. Thrombocytopenia and prognosis in intensive care. Crit Care Med 2000;28:1871-6.
4. Chakraverty R, Davidson S, Peggs K, Stross P, Garrard C, Littlewood TJ. The incidence and cause of coagulopathies in an intensive care population. Br J Haematol 1996;93:460-3.
5. Corwin HL, Parsonnet KC, Gettinger A. RBC transfusion in the ICU. Is there a reason? Chest 1995;108:767-71.
6. French CJ, Bellomo R, Finfer SR, Lipman J, Chapman M, Boyce NW. Appropriateness of red blood cell transfusion in Australasian intensive care practice. Med J Aust 2002;177:548-51.
7. Rao MP, Boralessa H, Morgan C, Soni N, Goldhill DR, Brett SJ, et al. Blood component use in critically ill patients. Anaesthesia 2002;57:530-4.
8. Stanworth SJ, Grant-Casey J, Lowe D, Laffan M, New H, Murphy MF, et al. The use of fresh-frozen plasma in England: high levels of inappropriate use in adults and children. Transfusion 2011;51:62-70.
9. Holli Halset J, Hanssen SW, Espinosa A, Klepstad P. Tromboelastography: variability and relation to conventional coagulation test in non-bleeding intensive care unit patients. BMC Anesthesiol 2015;15:28.
