Acute sepsis

Question 1

Definition of sepsis

Answer 1

life - threatening organ dysfunction; caused by disregulated host response to infection

Question 2

What’s septic shock?

Answer 2

Septic shock:

subset of sepsis, where there are profound

circulatory, cellular and metabolic abnormalities -> associated with a greater risk of death (as compared

to sepsis on its own)

Question 3

Why sepsis causes organ damage? (simple pathology)

Answer 3

Pathology:

• infective material in a blood stream -> decreased oxygenation to the tissues - infective material -> immune response from white blood cells (as infective material is in the blood stream) -> release of NO -> vasodilation -> increased vessel diameter -> increased leakiness (spread of the infection to other organs)

* low tissue perfusion is also due to increased leakiness -> more tissue fluid accumulation -> more barrier for oxygen diffusion

• damage to blood vessels due to white blood cells releasing lytic enzymes against infected material (# to blood vessels as a side effect) -> coagulation factors will activate -> disseminated intravascular coagulation

Question 4

Possible complications of septic shock (only name 4 conditions)

Answer 4

• DIC (disseminated intravascular coagulation)
• ARDS (acute respiratory distress syndrome)
• SIRS (systemic inflammatory response syndrome)
• MODS (multiple organ dysfunction syndrome)

Question 5

Why ARDS is a possible compication of a septic shock? (pathophysiology)

Answer 5

lungs are highly vascularised -> so during septic shock -> blood vessels are

damaged -> oxygen cannot be absorbed properly into the lungs

Question 6

What is needed to diagnose SIRS?

Answer 6

SIRS = systemic inflammatory response syndrome

(2 criteria + infection) = SIRS

Question 7

What’s MODS?

Answer 7

MODS - Multi-Organ Dysfunction Syndrome

• progressive dysfunction of 2 or more organ systems that result from uncontrolled inflammatory response (SIRS)

Question 8

Features / clinical presentation of a septic shock

Answer 8

• Fever (>38.3 degrees) or hypothermia (<36.0 degrees)
• HR > 90/min (or more than 2 SD above normal value for age)
• Tachyopnea (increased RR) >20 / min
• altered mental status
• significant oedema or positive fluid balance (as decreased urine output)
• warm skin: skin is the largest organ in the body -> blood vessels dilate -> heat is taken up from the vessels
• hyperglycaemia (plasma glucose >140 mg/dL or 7,7mmol/L) in absence of diabetes

Question 9

Inflammatory blood changes (on the blood test)

Answer 9

• leukocytosis (WBC count >12, 000)

OR

• leukopenia (WBC count < 4, 000)
• normal WBC count but >10% of immature forms
• increased C reactive protein
• increased plasma procalcitonin (PTC)

*PCT - it is a peptide precursor of calcitonin; it is involved with

calcium homeostasis

*Normal level of PCT is below detection (0.01 ug/L); PCT rises in response to pro-inflammatory stimulus (e.g. bacteria) -> it is therefore acute phase reactant

Question 10

How to calculate MAP

Answer 10

MAP = [(2x diastolic) + systolic]/ 3

*diastole counts twice of the systole because 2/3 pf cardiac cycle is spent in diastole

Question 11

What’s normal MAP?

Answer 11

Normal MAP: 70 - 110

*we need MAP of at least 60 to perfuse arteries, brain and kidneys

Question 12

Possible hemodynamic abnormalities in inflammation (that leads to shock)

Answer 12

• hypotension: BP <90 mm Hg
• MAP <70 mm Hg

OR: severe decrease >40 mmHg in adults

Question 13

How to recognize organ dysfunction?

Possible abnormalities

Answer 13

• arterial hypoxemia (PaO2/FiO2 is <300)
• acute oliguria (urine output <0.5 mL/kg/hr for at least 2 hr despite adequate fluid resuscitation)
• creatine increase (>0.5 mg/dL or 44.2 umol/L)
• ileus (absent bowel sounds)
• coagulation abnormalities (INR >1.5 or aPTT > 60 s)
• raised D-Dimer (as thrombocytopenia)

Question 14

What does PT measure?

Answer 14

PT - time it takes for plasma to clot after tissue factor is added

• it measures quality of extrinsic pathway of coagulation

Question 15

What’s INR?

Answer 15

Question 16

What type of shock a septic shock is?

Answer 16

Distributive

Question 17

Sepsis 6 steps

Answer 17

Question 18

What are normal levels of lactate?

Answer 18

•Normal range (unstressed patient): 0.5 - 1 mmol/L

• Critical illness patient’s normal value: less than 2 mmol/L
• Hyperlactatemia: 2 mmol/L and above

Question 19

What’s lactate?

Answer 19

Lactate

• byproduct by anaerobic pathway
• indicates inceased glycolysis (used in anaerobic pathway of respiration), that cannot bind to H+ ions -> acidosis (as H+ concentration is increased)

Question 20

Clinical presentation of lactic acidosis

Answer 20

nausea, vomiting, Kussmaul breathing (deep and laboured), weakness

Question 21

Possible causes of lactic acidosis

Answer 21

causes: inborn error of metabolism, decreased tissue oxygenation (from low perfusion), medication or intoxication

Question 22

What blood tests in Ix for sepsis?

Answer 22

Blood tests (sample obtained from two distinct sites) to test for:

• evidence of infection
• clotting problems
• abnormal liver or kidney function
• impaired oxygen availability
• electrolyte imbalances

Question 23

What other tests do for sepsis (other than bloods/imaging)

Answer 23

Other tests - depend on the symptoms -> to on the body fluids such as:

• urine - in case of suspicion of UTI infection
• Wound secretions - in case of a wound appearing to be infected
• Respiratory secretions - if the mucous has been coughed out

Question 24

Possible imaging tests in sepsis + justification

Answer 24

Imaging scans

• X ray - to visualise problems in the lungs
• CT - in case of infections in the appendix, pancreas or intestines
• USS- useful to check for the infections within the gallbladder or the ovaries
• MRI- useful in identifying soft tissue infections (e.g. abscess in the spine)

Question 25

How much O2 to give in septic pt?

Answer 25

Give 15L of O2 (if sats <94%)

*in COPD aim for sats 88-92%

Question 26

What type and how much IV fluids to give in sepsis?

Answer 26

give 500 ml IV bolus of crystalloid* (e.g. Hartmann’s)

If systolic BP is <90 mmHg -> give further boluses up to 30 ml/kg

If systolic BP remains <90 mmHg -> refer to critical care

*crystalloid - volume expander

Question 27

What (other than antibiotics) med may be possible given in septic patient?

Answer 27

• vasopressors - if BP remains low after receiving IV fluids -> to constrict blood vessels and therefore increase BP
• Low doses of corticosteroids
• Insulin - to maintain stable blood sugar level
• Drugs that modify immune system responses
• Painkillers
• Sedatives

Question 28

What blood tests to perform in septic patient?

Answer 28

• FBC
• Chem profile (U&E, LFT, calcium and phosphate)
• Bicarbonate
• C-reactive protein
• Glucose
• Clotting
• Lactate
• Arterial blood gas

Question 29

Urine output monitoring in septic patient (frequency, aim)

Answer 29

• hourly
• fluid balance chart
• Possible catheter insertion (as more practical and accurate)
• Aim for: 0.5 ml/kg/hr

Question 30

Criteria for the diagnosis of severe sepsis

Answer 30

If any of the following applies -> severe sepsis

• SBP <90 or MAP <65 (despite fluid resuscitation)
• supplemental O2 is required (FiO2 >0.5) to keep sats >90%
• INR is >1.5, APTT >60 seconds or platelets <100 (*aPTT - activated partial prothrombin time)
• urine output <0.5 ml/kg/hr
• lactate >2.0 mmol/hr
• immunosuppressed patient

Question 31

What’s the fluid challenge?

Answer 31

Fluid challenge:

1. Give 250 - 500 mls via 16g cannula

Interpet

2. Measure pulse and blood pressure

If BP improves -> patient is hypovolaemic -> give further fluids

3. Reasses