quality education for a healthier scotland blood cultures

Quality Education for a Healthier Scotland

Blood Cultures


Learning Outcomes

• On completion of this resource you should be able to:

• Understand the appropriate use of blood cultures as a clinical test

• Describe the rationale for utilising an Aseptic Technique in taking blood cultures

• Describe how to ensure an effective Aseptic Non Touch Technique when taking blood cultures


What is a blood culture ?

• A microbiological culture of the blood to detect infection with a micro organism, specifically bacteria or candida.

• The blood is usually a sterile substance.

• If an organism grows - more tests will identify type and antibiotic sensitivity


Contamination

Growth of organisms in the blood culture bottle that were not present in the patient’s blood stream

Introduced during sample collection from:• Patients skin, • Equipment used to take sample and transfer it to bottle• Hands of the person taking sample

Contamination rates• Estimated that at present 10% of all blood cultures in

Scotland are contaminated.• Aiming for an in patient rate of <3%.


Contamination of samples has important consequences

1. Patient Unnecessary investigations Errors in clinical interpretationAdministration of inappropriate treatment

2. Inappropriate use of antibiotics Potentiates emergence of multi-resistant organisms Increases risk of Clostridium difficile infection

3. Cost to the health service Average length of stay increased by 4.5 days Average overall cost of treatment increased by £5,500


Contamination of samples has important consequences

4. SurveillanceDecreases accuracy of surveillance data on

septicaemia

5. Performance management Negatively affects performance management

targets around patient safety


Indications for Blood Cultures

Presence of 2 or more of SIRS (Systemic Inflammatory Response Syndrome) criteria:

Core Temperature <36 or>38Respiratory Rate >20 per minWCC >12 or <4 x109Pulse >90bpmAltered mental stateBM> 8mmol (if not a diabetic)

Even if only one of these criteria is present there may be clinical indications to take a Blood Culture sample


When to take Blood Cultures?

When• After indications met• Before administration of antibiotics or a change of antibiotics• If patient is on antibiotics, blood cultures should be taken

immediately before next dose (with exception of paediatric patients).

• How many sets of cultures?• Obtaining more than one set of cultures :• Significantly increase the sensitivity of the test• Assists with determining whether a sample is contaminated


Taking Blood Cultures - venepuncture

The site that blood is taken from has significant impact on the

potential for a culture to be contaminated

For venepuncture avoid :• Femoral vein - adequate skin disinfection

difficult• Existing peripheral cannulae • Sites above peripheral cannulae • Drawing multiple sets from a single puncture


How to take Blood Cultures

Equipment required:1 Sharps bin2 Gloves (non-sterile)3 Needle and Syringe or Safety Blood Collection system4 Alcohol based disinfectant5 Dressing as required6 Blood Culture bottles (plus other vacutainers if

required)7 Blood culture sticker for notes


How to take a blood culture(1)

1. Taking a blood culture is clinically indicated for this patient

2. Decontaminate blood culture bottle topsRemove lids and disinfect rubber access points with an alcohol based disinfectant

3. Carry out hand hygiene before touching the patientDecontaminate hands before and after patient contact, and before applying examination gloves

4. Apply alcohol based skin antiseptic and leave to dryPatient’s skin is decontaminated at insertion site with alcohol based antiseptic and is allowed to dry for 30 seconds before taking the blood culture


How to take a blood culture(1)

5. Don’t touch critical partsOpen and prepare sterile equipment without touching critical parts. The needle/device is held and positioned without touching the part that is inserted into the patient Avoid touching the skin at the insertion site after disinfection

6. Inoculate blood culture bottles firstDispensing blood into other containers before the culture bottles increases the risk of contamination

7. Document rationale, date and time of blood culture and operatorBlood culture sticker is completed and inserted into patient case notes


How to take a Blood Culture – Central Site

Blood cultures may be taken from a central line using aseptic technique.

If investigating infection from a central line: • Decontaminate the needle free connector using a

compatible alcohol based antiseptic – leave to dry for 30 seconds

• Take a sample from a peripheral vein first to minimise contamination

• Then take a sample from the central line


Monitoring of Practice

1. Feedback to operator if culture is contaminated

Sample note sticker:Blood Culture Case Note Sticker

Patient Name: CHI:

Please circle as appropriatellllllllllllll

WCC < 4 or > 12 x 109/l (if avail) Y/N

Altered Mental State Y/N

Date: Time Taken:

Sign:

Resp Rate > 20rpm Y/N BC top cleaned with Alcohol Y/N

BM > 8mmol (If not Diabetic) Y/N

Hand Hygiene & Gloves Y/N

Skin Cleaned with Chloraprep Y/N

Aseptic non touch technique Y/N

BC’s taken before other bloods Y/N

Print:

If Y to 2 or more of the above & has signs suggesting new infection → Y/NRefer to Severe Sepsis Screening Tool

Blood Culture (BC) Procedure

Contact Number:

Heart Rate > 90bpm Y/N

SBP < 90mmhg Y/N

Temperature < 36° or > 38° Y/N


Monitoring of Blood Culture Practice

2. Rate of contamination (i.e. number of contaminated cultures divided by the number of cultures taken per month)

3. Audit tool of percent compliance with the blood culture critical elements checklist

quality education for a healthier scotland blood cultures

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