Severe sepsis

Definitions

Systemic inflammatory response syndrome (SIRS)

SIRS criteria is met if 2 or more are present:

  1. Temperature > 38°C or < 36°C
  2. Pulse > 90 beats/min
  3. Respiratory Rate (RR) > 20 or PaCO2 < 4.3 kPA
  4. WBC > 12,000 or < 3000/mm3 (or > 10% immature bands)

Sepsis is "the systemic inflammatory response syndrome (SIRS) during an infection."

Severe sepsis.

Sepsis and at least 1 organ dysfunction:

Lactate in Severe Sepsis

Hi Lactate (& rate of clearance) is prognostic

Initial Lactate

  • 0-2 Normal
  • >2 (If criteria for sepsis) = Severe Sepsis
  • >4 (If criteria for sepsis) = Septic shock

After the initial sepsis care duties have been performed (oxygen, fluids, swabs & cultures, antibiotics, blood tests, urinary catheter for hourly U/O) the Lactate should be repeated:

Repeat Lactate

  • 0-2 Normal
  • >2
    • If initial Lactate was >2 but <4 then this is Severe Sepsis unless the BP is low (see below)
    • If initial Lactate was >4 then this indicates Severe Sepsis
  • >4 Septic Shock (NB if BP was never low then =‘Cryptic Shock’). If, despite initial resuscitation (O2, fluids, swabs & cultures, antibiotics, blood tests and urinary catheter for hourly U/O), the BP remains low (SBP<90, MAP<65) then this is Septic Shock irrespective of the Lactate.

Septic shock. Sepsis and refractory hypotension defined as systolic blood pressure < 90 mm Hg, mean arterial pressure (MAP) < 65 mm Hg, or decrease of 40 mm Hg in systolic pressure compared with baseline; unresponsive to crystalloid fluid challenge of 20 to 40 mL/kg.

Bacteremia. Presence of viable bacteria in the blood; found in about 50% of cases of severe sepsis and septic shock; whereas 20% to 30% of patients will have no cause identified from any source.

Initial Resuscitation

Begin resuscitation immediately in patients with hypotension or elevated serum lactate.

Resuscitation goals:

Systemic inflammatory response syndrome (SIRS)

Sepsis

Severe sepsis

Septic shock

Two or more of the following:

  • Temp >38.5 or <35
  • Heart rate >90bpm
  • Resp rate >20bpm or arterial CO2 tension <32mmHg or need for mechanical ventilation
  • WCC >12 or <4 or immature forms >10%

SIRS and documented infection (culture or gram stain of blood, sputum, urine or normally sterile body fluid positive for pathogenic microorganism; or focus of infection identified by visual inspection).

Sepsis and at least one sign of organ hypoperfusion or organ dysfunction:

  • Areas of mottled skin
  • Capillary refilling time ≥3 sec
  • Urinary output <0.5ml/kg for at least 1 hr or renal replacement therapy
  • Lactates >2mmol/L
  • Abrupt change in mental status or abnormal electroencephalogram
  • Platelet count <100x 109/L or disseminated intravascular coagulation
  • Acute lung injury – acute respiratory distress syndrome
  • Cardiac dysfunction (echocardiography)

Severe sepsis and one of:

  • Systemic mean blood pressure <60mmHg (<80mmHg if previous hypertension) after 40-60ml/kg saline, or pulmonary capillary wedge pressure between 12 and 20 mmHg.
  • Need for dopamine >5mcg/kg per min or norepinephrine or epinephrine >0.25mcg/kg per min to maintain mean blood pressure above 60 mmHg (80 mmHg if previous hypertension).

Initial Fluid therapy

  • Give 500–1000 ml of crystalloids over 30 mins
  • Repeat if BP and urine output do not increase (with no evidence of intravascular volume overload).

Diagnosis

Take Blood cultures before antibiotics

  • At least one percutaneous
  • One through any line >48 hrs old
  • Get cultures from other sites as indicated - cerebrospinal fluid, respiratory, secretions, urine, wounds, and other body fluids.

Antibiotics

  • IV antibiotics within first hour of recognition of severe sepsis.
  • Administer one or more drugs that are active against likely bacterial or fungal pathogens.
  • Use combination therapy for neutropaenic patients and those with Pseudomonas infections.

Source control

  • Look for the source of infection
  • ? Abscess drainage / tissue debridement.
  • Choose the source control measure that will cause the least physiological upset and still accomplish the clinical goal.

Vasopressors

  • Start vasopressors when fluid challenge fails to restore adequate blood pressure and organ perfusion.
  • Norepinephrine or Dopamine (via central line) are the vasopressors of choice.
  • Consider small boluses (ask your senior first) of 1:100,000 Adrenaline while setting up the NA infusion
  • Titrate vasopressors to MAP of >65 mmHg
  • Do not use low-dose Dopamine for renal protection
  • Place an arterial line
  • Vasopressin can be considered later (after transfer to ITU)

Steroids

  • Treat patients who still require vasopressors despite fluid replacement with hydrocortisone (200–300 mg/day)

Or

  • Perform 250-microgram ACTH Stimulation Test and discontinue steroids in responders

Fluid therapy

  • Give 500–1000 ml of crystalloids over 30 mins
  • Repeat if BP and urine output do not increase (with no evidence of intravascular volume overload).

Blood products

  • Once tissue hypoperfusion improved (and no significant coronary artery disease or acute haemorrhage), transfuse with red blood cells to a target a haemoglobin of 7.0 - 9.0 g/dl.
  • Do not use (FFP) Fresh Frozen Plasma to correct laboratory clotting abnormalities, unless there is bleeding or planned invasive procedures
  • Do not use antithrombin therapy.
  • Administer platelets when counts are less than 5000/mm3 (5 x 109/L), regardless of bleeding.
  • Transfuse platelets when counts are 5000 to 30,000/mm3 (5-30 x 109/L) and there is significant bleeding risk.
  • Higher platelet counts (= 50,000/mm3 [50 x 109/L]) are required for surgery or invasive procedures.

ARDS

  • Avoid high Tidal Volumes with high plateau pressures.
  • Goal = reduce TV over 1-2 hours to 6 ml per kg (lean) body wt with end-inspiratory plateau pressures <30 cm H2O
  • If necessary, minimize plateau pressures and tidal volumes, by allowing PaCO2 to increase above normal.
  • Set a minimum amount of positive end-expiratory pressure (PEEP) to prevent lung collapse at end expiration.
  • To prevent ventilator-associated pneumonia maintain mechanically ventilated patients in a semi-recumbent position (head up 450), unless contraindicated.

Glucose control

  • Maintain blood glucose < 8.3mmol/L) following initial stabilization - insulin +/- glucose) infusion

Recombinant human activated protein C (rhAPC)

rhAPC is recommended in patients at high risk of death (APACHE II ≥ 25, sepsis-induced multiple organ failure, septic shock, or sepsis-induced acute respiratory distress syndrome) and with no absolute contraindication related to bleeding risk or relative contraindication that outweighs the potential benefit of rhAPC.

Renal replacement

DVT

  • Use either low-dose unfractionated heparin or LMWH.

Provide stress ulcer prophylaxis.

  • With H2 receptor inhibitors.

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