Blood Cultures

1. Blood Cultures

2. 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

3. 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

4. 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%.

5. Contamination of samples has important consequences • Patient Unnecessary investigations Errors in clinical interpretation Administration 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

6. Contamination of samples has important consequences 4. Surveillance Decreases accuracy of surveillance data on septicaemia 5. Performance management Negatively affects performance management targets around patient safety

7. Indications for Blood Cultures Presence of 2 or more of SIRS (Systemic Inflammatory Response Syndrome) criteria: Core Temperature <36 or>38 Respiratory Rate >20 per min WCC >12 or <4 x109 Pulse >90bpm Altered mental state BM> 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

8. 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

9. 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

10. How to take Blood Cultures Equipment required: • Sharps bin • Gloves (non-sterile) • Needle and Syringe or Safety Blood Collection system • Alcohol based disinfectant • Dressing as required • Blood Culture bottles (plus other vacutainers if required) • Blood culture sticker for notes

11. How to take a blood culture(1) • Taking a blood culture is clinically indicated for this patient • Decontaminate blood culture bottle tops Remove lids and disinfect rubber access points with an alcohol based disinfectant 3. Carry out hand hygiene before touching the patient Decontaminate hands before and after patient contact, and before applying examination gloves 4. Apply alcohol based skin antiseptic and leave to dry Patient’s skin is decontaminated at insertion site with alcohol based antiseptic and is allowed to dry for 30 seconds before taking the blood culture

12. How to take a blood culture(1) 5. Don’t touch critical parts Open 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 first Dispensing blood into other containers before the culture bottles increases the risk of contamination 7. Document rationale, date and time of blood culture and operator Blood culture sticker is completed and inserted into patient case notes

13. 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

14. Blood Culture Case Note Sticker Patient Name: CHI: Blood Culture (BC) Procedure Please circle as appropriate llllllllllllll Resp Rate > 20rpm Y/N BC top cleaned with Alcohol Y/N Hand Hygiene & Gloves Y/N Heart Rate > 90bpm Y/N SBP < 90mmhg Y/N Skin Cleaned with Chloraprep Y/N Temperature < 36° or > 38°Y/N Aseptic non touch technique Y/N WCC < 4 or > 12 x 109/l (if avail) Y/N BC’s taken before other bloods Y/N Altered Mental State Y/N BM > 8mmol (If not Diabetic) Y/N Date: Time Taken: If Y to 2 or more of the above & has signs suggesting new infection →Y/N Refer to Severe Sepsis Screening Tool Sign: Print: Contact Number: Monitoring of Practice • Feedback to operator if culture is contaminated Sample note sticker:

15. 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

16. References • NHS Quality Improvement Scotland; Health Protection Scotland. Blood Culture Driver Diagram, Implementation Framework, Priority Elements Checklist, Data Measurement Tool and Measurement Plan – Working Draft. Scotland: NHS QIS/HPS. 2011 version1.1 • Further references and bibliography can be found in the teaching notes