Sepsis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.D. [2]
Overview
Sepsis is a serious medical condition characterized by a whole-body inflammatory state caused by infection. Traditionally the term sepsis has been used interchangeably with septicaemia and septicemia ("blood poisoning"). However, these terms are no longer considered synonymous; septicemia is considered a subset of sepsis. Septic shock is a serious medical condition caused by decreased tissue perfusion and oxygen delivery as a result of infection and sepsis. It can cause multiple organ failure and death. Its most common victims are children, immunocompromised individuals, and the elderly. This is because their immune systems cannot cope with the infection as well as those of full-grown adults. The mortality rate from septic shock is approximately 50%.
Sepsis [1], [2]
Sepsis is considered present if infection is highly suspected or proven and two or more of the following systemic inflammatory response syndrome (SIRS) criteria are met:
- Heart rate > 90 beats per minute
- Temperature < 36 (96.8 °F) or > 38 °C (100.4 °F)
- Tachypnea > 20 breaths per minute or, on blood gas, a PaCO2 < 32 mm Hg
- White blood cell count < 4000 cells/mm³ or > 12000 cells/mm³ (< 4 x 109 or > 12 x 109 cells/L), or > 10% band forms (immature white blood cells / bandemia).
Consensus definitions however continue to evolve with the latest expanding the list of signs and symptoms of sepsis to reflect clinical bedside experience.[3]
Severe Sepsis [1]
Patients are defined as having "severe sepsis" if they have sepsis plus
- Signs of systemic hypoperfusion
- Capillary refilling time > 3 seconds
- Urine output < 0.5mL/kg for at least 1 hour or requirement of renal replacement therapy
- End organs dysfunction
- Left ventricular systolic dysfunction (echocardiographic findings / cardiac index)
- Acute changes in sensorium / abnormal EEG findings
- Disseminated intravascular coagulation
- Thrombocytopenia < 100,000 platelets/mL
- Acute respiratory distress syndrome (ARDS)
- Skin mottlings
- Serum lactate > 2 mmol/L.
Septic Shock [1]
Septic shock is defined as sepsis with refractory arterial hypotension. Refractory arterial hypotension is further defined as:
- Mean systemic blood pressure (SBP) of < 60 mm Hg or < 80 mm Hg (in hypertensives) despite adequate fluid resuscitation.
- Adequate fluid resuscitation is defined as infusion of following at the said rates:
- 20 to 30 mL/kg of starch,
- 40 to 60 mL/kg of saline solution
- Measured pulmonary capillary wedge pressure - 12 to 20 mmHg
- Central venous pressure of 8 to 12 mmHg
- Adequate fluid resuscitation is defined as infusion of following at the said rates:
- Maintenance of the systemic mean blood pressure of > 60 mmHg or > 80 mmHg (in hypertensives) despite adequate fluid resuscitation requires:
- Dopamine > 5 mcg/kg/min
- Norepinephrine < 0.25 mcg/kg/min
- Epinephrine < 0.25 mcg/kg/min
Refractory Septic Shock
Refractory Septic shock is defined as sepsis with refractory arterial hypotension and maintenance of the systemic mean blood pressure of > 60 mmHg or > 80 mmHg (in hypertensives) despite adequate fluid resuscitation requires:
- Dopamine > 15 mcg/kg/min
- Norepinephrine > 0.25 mcg/kg/min
- Epinephrine > 0.25 mcg/kg/min
- Adequate fluid resuscitation is defined as infusion of following at the said rates:
- 20 to 30 mL/kg of starch,
- 40 to 60 mL/kg of saline solution
- Measured pulmonary capillary wedge pressure - 12 to 20 mmHg
- Central venous pressure of 8 to 12 mmHg
Multiple Organ Dysfunction Syndrome
- It is defined as a progressive organ dysfunction that require interventions for maintenance of homeostasis.
- It is the most severe manifestation of either SIRS or sepsis continuum.
- Primary MODS can be directly connected to the source of infection. However, secondary MODS occurs as a result of host response to the primary insult.
- Parameters used to judge MODS are:
- Liver - Serum bilirubin
- Nervous system - Glasgow coma scale
- Hematology - Platelet count
- Renal - Serum creatinine
- Respiratory - PO2/FiO2 ratio
- Cardiovascular - Pressure-adjusted heart rate = Heart rate multiplied by the ratio of central venous pressure and mean arterial pressure
Neonatal Sepsis
The criteria for diagnosing an adult with sepsis does not apply to infants under one month of age (neonatal sepsis). In infants, only the presence of infection plus a "constellation" of signs and symptoms consistent with the systemic response to infection are required for diagnosis.
Systemic Inflammatory Response Syndrome [1], [4]
Criteria for SIRS were agreed upon in 1992.[5] SIRS can be diagnosed when two or more of the following are present:[6]
- Heart rate > 90 beats per minute
- Temperature < 36 (96.8 °F) or > 38 °C (100.4 °F)
- Tachypnea > 20 breaths per minute or, on blood gas, a PaCO2 < 32 mm Hg
- White blood cell count < 4000 cells/mm³ or > 12000 cells/mm³ (< 4 x 109 or > 12 x 109 cells/L), or > 10% band forms (immature white blood cells / bandemia).
Severe SIRS
- When two or more of the systemic inflammatory response syndrome criteria are met without evidence of infection, patients may be diagnosed simply with "SIRS."
- Patients with SIRS and acute organ dysfunction may be termed "severe SIRS."
Difference between SIRS and Sepsis
SIRS with a suspected or proven infection is called sepsis.
Simply stated:
- SIRS + infection = sepsis
Related Chapters
- Meningococcemia
- Anaphylactic shock
- Cardiogenic shock
- Neurogenic shock
- Sepsis
- Shock
- Septic shock
- Systemic inflammatory response syndrome (SIRS)
References
- ↑ 1.0 1.1 1.2 1.3 Dellinger RP, Levy MM, Carlet JM, Bion J, Parker MM, Jaeschke R, Reinhart K, Angus DC, Brun-Buisson C, Beale R, Calandra T, Dhainaut JF, Gerlach H, Harvey M, Marini JJ, Marshall J, Ranieri M, Ramsay G, Sevransky J, Thompson BT, Townsend S, Vender JS, Zimmerman JL, Vincent JL (2008). "Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008". Critical Care Medicine. 36 (1): 296–327. doi:10.1097/01.CCM.0000298158.12101.41. PMID 18158437. Retrieved 2012-09-16. Unknown parameter
|month=ignored (help) - ↑ Bone RC, Balk RA, Cerra FB, Dellinger RP, Fein AM, Knaus WA, Schein RM, Sibbald WJ. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine. Chest. 1992 Jun;101(6):1644-55. PMID 1303622.
- ↑ Levy MM, Fink MP, Marshall JC, Abraham E, Angus D, Cook D, Cohen J, Opal SM, Vincent JL, Ramsay G; SCCM/ESICM/ACCP/ATS/SIS. 2001 SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference. Crit Care Med. 2003 Apr;31(4):1250-6.
- ↑ Bone RC, Balk RA, Cerra FB, Dellinger RP, Fein AM, Knaus WA, Schein RM, Sibbald WJ. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine. Chest. 1992 Jun;101(6):1644-55. PMID 1303622.
- ↑ "American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference: definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis". Crit. Care Med. 20 (6): 864–74. 1992. PMID 1597042.
- ↑ Tslotou AG, Sakorafas GH, Anagnostopoulos G, Bramis J. Septic shock; current pathogenetic concepts from a clinical perspective. Med Sci Monit. 2005 Mar;11(3):RA76-85. PMID 15735579. Full Text.