Prophylaxis Flashcards
What preoperative drugs are prescribed?
Thromboprophylaxis
Prophylactic antibiotics
What is the indication for prophylactic subcutaneous LMWH?
Reduce risk of DVT and fatal PE in:
-All patients over 20y undergoing abdominal surgery
What is the dose of prophylactic Dalteparin? When should it be given?
2,500 units subcutaneously OD
Started at least 2hr preoperatively
Name 1 contraindication of preoperative LWMH
Patients having neck surgery
Name 3 high risk patients for preoperative DVT or PE
Oral contraceptive pill Previous DVT or PE Obese patients Intra-abdominal malignancy Pelvic or lower limb surgery patients Pregnant Amputees
How should the dosage of prophylactic LMWH be changed in high risk patients?
Larger prophylactic dose of subcutaneous LMWH
e.g. Dalteparin 2,500 ➔ 5,000 units
Name the 3 types of thromboprophylaxis
Mechanical devices: TEDS and pneumatic compression boots
Unfractionated heparin
LMWH SC
Describe the mechanism of action of Heparin
Irreversibly binds to ATIII ➔ increases inactivation of factors IIa and Xa
What is the dosage of unfractionated heparin for thromboprophylaxis in surgical patients?
5000 units taken 2hr pre-operatively
Describe the mechanism of action of LMWH
Irreversibly binds to ATIII ➔ increases inactivation of factor Xa (preferential) and IIa
What blood monitoring is required if thromboprophylactic unfractionated heparin is used?
APTT - maintain between 50-70
Name 2 LMWH drugs
Dalteparin
Enoxaparin
How is DVT risk assessed for VTE prophylaxis?
All patients are assessed for risk factors on admission and after 24hr in hospital.
Risk according to procedure factors and patient factors.
These are balanced against bleeding risks and risks of compression devices.
Name 2 procedure factors that increase DVT risk
Prolonged anaesthetic time
Lower limb or pelvic surgery
Name 3 patient factors that increase DVT risk
Immobility Malignancy Age Dehydration Obesity Diabetes Cardiorespiratory disease Inflammatory pathology OCP or HRT PMH or FHx of thromboembolic disease
Name 3 bleeding risks that should be considered when assessing need for prophylactic heparin or LMWH
Active bleeding
Stroke
Invasive procedure
Bleeding disorders
Name a risk of compression devices for thromboprophylaxis
Peripheral vascular disease
What are the indications for prophylactic antibiotics?
To minimise wound or prosthesis infection
To minimise subacute bacterial endocarditis
Which antibiotics are used for prophylaxis?
Depends on nature of surgery, countering the effect of potential spillage from colonised organs once opened.
Consult trust policy for antibiotics for specific surgeries and patients.
What are the main wound contaminants in colonic surgery? Which antibiotics are used?
Anaerobes: Bacillus fragilis
Gram -ve bacilli: E. coli, Pseudomonas, Klebseilla
Skin: Staph aureus
Cefuroxime and Metronidazole
Augmentin (penicillin)
What are the principles of antibiotic prophylaxis?
High circulating serum level of ABX at time of potential contamination
Rarely needed to be continued post-op
Many clean wounds do not require prophylactic ABX
High risk patients may require extended or specific prophylaxis
What is the average length of prophylactic antibiotic courses?
1-3 days
Name 2 causative agents of bacterial endocarditis
Staph aureus
Strep viridans
How does subacute endocarditis differ to acute endocarditis?
Subacute usually occurs on damaged valves.
Name 2 risk factors for subacute endocarditis
Prosthetic heart valve
Rheumatic heart disease (rare)
Outline thromboprophylaxis for patients with low risk of DVT
TEDS stockings only
Outline thromboprophylaxis for patients with medium risk of DVT
TEDS stockings
+
Enoxaparin 30mg SC OD or Dalteparin 2500U SC OD
Outline thromboprophylaxis for patients with high risk of DVT
TEDS stockings
+
Enoxaparin 30mg SC BD or
Dalteparin 5000U SC OD
Name 3 patient factors that affect the need for post-op thromboprophylaxis
Age
BMI
Personal or FHx of VTE
Personal or FHx of thrombophilia (increased clotting)
Name 3 procedural factors that affect the need for post-op thromboprophylaxis
Orthopaedic operations Plaster cast immobilisation Spinal surgery Pelvic operations Prolonged anaethesia Malignancy operations
