Pre and Post Operative Care

Question 1

What is the Role of The Pharmacist in Pre and Post Operative Care?

Answer 1

• Complete an accurate Medication History of the patients pre-admission
• Work with the anaesthetist and the surgical team to make decisions on whether medications should be held or continued prior to surgery
• Educate and if necessary organise the patients medication regimen pre-operatively (Webster Pack, Nursing home resident)

Question 2

Pre-Operative Care – Anti-coagulation and Anti-platelets

• What is there a balance between?
• Patients are classed as what and how is this measured?
• What other input may be required?

Answer 2

• Balance between bleeding risk and thromboembolic complications
• Class patient as ‘high risk’ or ‘low risk’ for thromboembolism
  
  • Guides decision as whether to hold anti-coagulation or if bridging therapy is required
  • Tools: CHA₂DS₂VASc, HAS-BLED
• Haematology input may be required e.g. if a patient who has previously had heparin induced thrombocytopenia

Question 3

Pre-Operative Care – Anti-coagulation and Anti-platelets

• What are the Guidelines for High Risk Patients?
  
  • Warfarin held for?
  • Enoxaparin initiated for?
    
    • What must be assessed before initiating?
    • Last dose of enoxaparin before surgery?
• What needs to be checked the morning of procedure?
• If INR > 1.5?

Answer 3

• Hold warfarin 5 days prior to procedure
• Initiate enoxaparin 3 days before surgery
  
  • Assess the patients estimated CrCl before recommending a dose
  • Last dose of enoxaparin to be given 24hrs pre-operatively at half therapeutic dose – patient will need education on when to cease the enoxaparin
• Check INR morning of procedure (aim INR <1.5) – patients bleeding risk reduced if INR <1.5
  
  • If INR >1.5, vitamin K indicated
    
    • Depending on the type and length of surgery, reversal of warfarin may be necessary even after holding for 5 days

Question 4

Pre-Operative Care – Anti-coagulation and Anti-platelets

• What are the Guidelines for Low-Risk Patients?
  
  • Is bridging therapy required?
  • Warfarin held when?
  • What needs to be checked?

Answer 4

• No bridging therapy required
• Hold warfarin for 5 days prior to procedure
• Check INR morning of procedure (aim INR <1.5)
  
  • If INR >1.5, vitamin K indicated

Question 5

Pre-Operative Care – Anti-coagulation and Anti-platelets

• Warfarin Post Surgery
  
  • When can warfarin and enoxaparin be re-started?
    
    • What must patients have?
    • What needs to be monitored?
    • When can enoxaparin cease?

Answer 5

• Warfarin and enoxaparin can usually be re-started 24-72 hrs post surgery
  
  • Patients need to have adequate haemostasis (Hb, platelets, INR etc) – bloods monitored daily to ensure this
    
    • Renal function monitored and enoxaparin dose adjusted accordingly
  • Enoxaparin can cease when INR therapeutic

Question 6

Pre-Operative Care – Anti-coagulation and Anti-platelets

• What risk must be reviewed to determine medication plan pre-operatively?
• What changes the length of time they need to be held compared to warfarin?
• What must be assessed?
• When can they be re-started?
  
  • Minor procedures
  • Major procedures

Answer 6

• Risk of bleeding vs thromboembolism must be reviewed to determine medication plan pre-operatively
• DOACs have shorter t1/2 lives compared to warfarin which changes the length of time they need to be held pre-operatively
• Renal function must be assessed
  
  • If GFR >80mL/min allow >24hrs between last dose of DOAC and surgery
• Re-starting:
  
  • 24 hrs post-surgery for minor procedures
  • 48-72hrs for major procedures

Question 7

Pre-Operative Care – Anti-coagulation and Anti-platelets

• Pre-operative Interruption of Anti-Platelets
  
  • Low risk patients may need to hold?
  • High risk patients may need to hold?

Answer 7

• Low-risk patients may need to hold anti-platelet therapy pre-operatively
  
  • E.g. patients on anti-platelet therapy for secondary prevention of MI
  • Hold anti-platelets 7 days pre-operatively
• High risk patients on dual anti-platelet therapy usually continue aspirin and hold second anti-platelet

Question 8

Pre-Operative Care – Diabetes Medications

• Diabetes Medicine Management in the Pre-Operative Setting
  
  • Diabetics have a high what? Following surgery?
  • Hyperglycaemia increases patients risk of what?
  • What measurement should all diabetics have taken pre-operatively?
  • Insulin-dependent diabetics (both Type 1 and Type 2) should be scheduled what?

Answer 8

• Diabetics have a higher incidence of morbidity and mortality following surgery
• Hyperglycaemia increases the patients risk of post-operative complications e.g. post-op infection
• All diabetics should have their HbA1c taken pre-operatively. When HbA1c >8%, the procedure may need to be re-scheduled
• Insulin-dependent diabetics (both Type 1 and Type 2) should be scheduled first on the operating list
  
  • Fasting and/or holding diabetes medication can lead to hypoglycaemia

Question 9

Pre-Operative Care – Diabetes Medications

• What are the Guideline Recommendations for Metformin?
  
  • When should it be held?
  • What may it increase the risk of?
  • Consider holding SR when?
  • When can it be restarted?

Answer 9

• Hold morning of surgery – may increase risk of renal insufficiency and increase patients risk of lactic acidosis
• Consider holding SR preparations evening before surgery
• Can re-start post-operatively when CrCl > 30mL/min

Question 10

Pre-Operative Care – Diabetes Medications

What are the Guideline Recommendations for Sulfonylureas?

• When is it held?
• Consider holding SR preparations when?

Answer 10

• Hold morning of surgery – patient will be fasting, therefore reduce risk of hypoglycaemia
• Consider holding slow release preparations evening before surgery

Question 11

Pre-Operative Care – Diabetes Medications

What are the Guideline Recommendations for GLP-1 analogues (exenatide, liraglutide)?

• When is it held and restarted?
• What are known adverse effects?

Answer 11

• Hold morning of surgery – restart when patient eating and drinking again post-operatively
• Known adverse effects of GLP-1 analogues are GI upset and delayed gastric emptying

Question 12

Pre-Operative Care – Diabetes Medications

What are the Guideline Recommendations for Thiazolidinediones (rosiglitazone, pioglitazone)?

• When is it held?
• What can it contribute to?

Answer 12

• Hold morning of surgery
• Can contribute to fluid retention

Question 13

Pre-Operative Care – Diabetes Medications

What are the Guideline Recommendations for DPP-4 inhibitors (sitalgliptin)?

• When are they held?
• What are they restarted?

Answer 13

• Hold morning of surgery
• Can restart when patient eating and drinking again post-operatively

Question 14

Pre-Operative Care – Diabetes Medications

What are the Guideline Recommendations for SGLT2 inhibitors?

• What are they associated with?
• Severe ketosis can occur when?
• When is it held?
• What was the previous recommendation?

Answer 14

• Associated euglycemic diabetic ketoacidosis
• Severe ketosis can occur when BGL < 16mmol/L
• Hold 3 days pre-op (48 hrs prior to the day of surgery – day of surgery = day 0)
• Previously the recommendation was to hold the morning of surgery

Question 15

Pre-Operative Care – Diabetes Medications

What are the Guideline Recommendations for Pre-op Insulin Modification on the Day of Procedure?

• Long acting insulins?
• Ultra-short, short and intermediate acting insulins?

Answer 15

• Long-acting insulins can be halved or held the evening prior and morning of surgery
• Ultra-short, short and intermediate acting insulins can be held morning of surgery

Question 16

Post-Operative Care – Nausea and Vomiting

• What are known risk factors?

Answer 16

• Preoperative nausea and vomiting
• Female gender
• Previous hx of motion sickness and/or PONV
• Non-smoker
• Age < 50 years
• Type of anaesthesia
• Opioid use
• Type and length of surgery

Question 17

Post-Operative Care – Nausea and Vomiting

• How is PONV predicted?

Answer 17

• Apfel’s simplified scoring system predicts the likelihood a patient will have PONV
• Each Apfel point increases the incidence of PONV by approximately 20%

Question 18

Post-Operative Care – Nausea and Vomiting

• Prophylaxis Treatment of PONV
  
  • Who receives preventative treatment?
  • What drugs are used? Are they equally effective?
  • What affects their risk?

Answer 18

• Patient’s identified as high-risk of PONV should be considered for preventative treatment
• Ondansetron, droperidol and dexamethasone have all been shown to be similarly effective
• Type of anaesthesia will affect their risk
  
  • Using propofol instead of a volatile anaesthetic (isoflurane, desflurane) reduces PONV by up to 19%
  • Substituting nitrogen for nitrous oxide can reduce PONV by up to 12%

Question 19

Post-Operative Care – Nausea and Vomiting

• Opioids contribute to PONV
  
  • What can reduce PONV?
  • NSAIDs?
  • IV Paracetamol?

Answer 19

• Multi-modal analgesia that include opioid-sparing medications can reduce PONV e.g. ketamine, pregabalin, NSAIDs
• NSAIDs have a 30%-50% opioid sparring effect and a reduction in PONV by 30%
• IV paracetamol administered pre-operatively to reduce PONV (due to the analgesia)

Question 20

Post-Operative Care – Nausea and Vomiting

• What is rescue therapy for PONV?

Answer 20

• Is the patient experiencing nausea or vomiting within 48 hours of surgery?
• Presence of contributing factors:
  
  • Inadequate pain relief
  • Opioid use
  • Hypotension
  • Hydration
  • Ileus
  • Blood in throat or stomach
  • Sudden movement
• Did the patient receive any anti-emetic intra-operatively? E.g. prophylactic treatment

Question 21

Post-Operative Care – Nausea and Vomiting

• What are the Risks associated with Ondansetron?

Answer 21

• Serotonin syndrome
• Long QT interval
• Pregnancy
• Apomorphine

Question 22

Post-Operative Care – Nausea and Vomiting

What are the Risks associated with Droperidol?

Answer 22

• Significant cardiac disease e.g. bradycardia, long QT
• Other drugs prolonging to QT e.g. amiodarone
• Parkinson’s disease
• Phaeochromocytoma

Question 23

Post-Operative Care – Nausea and Vomiting

What are the Risks associated with Dexamethasone?

Answer 23

Active Infection

Question 24

Post-Operative Care – Nausea and Vomiting

What are the Risks associated with Cyclizine?

Answer 24

Sedation

Question 25

Post-Operative Care – Nausea and Vomiting

How are the risks associated with anti-emetics managed?

Answer 25

• Alternate anti-emetic available?
• Can the patient be monitored? E.g. ECG
• Lower dose more suitable?
• Risk vs benefit of the patient receiving the anti-emetic?

Question 26

Prophylactic Antibiotics

• When are they indicated?
• What is the choice of abx based on?

Answer 26

• Prophylactic abx aren’t always indicated. They are considered if post-operatively there is a significant risk of infection
• The choice of abx should be based on which organism is most likely to cause the infection post-operatively e.g. staphylococcus aureus for plastic surgery

Question 27

Prophylactic Antibiotics

• What considerations are taken into account prior to prescribing?

Answer 27

• Individual risk factors
  
  • High risk of MRSA
  • Renal function
  • Allergies
• Type of surgery
  
  • E.g. small bowel resection vs. vascular surgery
• Timing of abx administration
  
  • IV bolus should be administered 15-30 mins prior to incision
  • IV infusion should begin 30-120 mins prior to incision

Question 28

Prophylactic Antibiotics

Guidelines for Plastic Surgery

• Types of Surgery
• Treatment Regimen
  
  • First line
  • MRSA risk
  • Penicillin Allergy

Answer 28

• Types of Surgery
  
  • Open reduction and internal fixation of fractures
  • Insertion of implants, mesh, prosthesis, screws, plates etc
  • Minor excisions and removal of non-infected lesions don’t require abx prophylaxis
• Treatment
  
  • First line = cefazolin 2g IV – coverage of staphylococcus aureus
  • High-risk of MRSA = add vancomycin 1g IV infusion to cefazolin
  • Severe penicillin allergy = substitute cefazolin for vancomycin 1g IV infusion

Question 29

Prophylactic Antibiotics​

• GI Surgery
  
  • Types?
• Treatment Regimen?
  
  • MRSA?
  • Penicillin Allergy?

Answer 29

• Types:
  
  • Colorectal: small bowel resection, appendectomy
  • Liver resection
  • Exploratory laparotomy/division of adhesions
  • Abx will need to provide anaerobic cover and potentially gram-negative bacilli
• Choice of Prophylactic Abx:
  
  • Metronidazole 500mg IV PLUS either
    
    • Cefazolin 2g IV or gentamicin 2mg/kg IV
    • High risk of MRSA = add vancomycin 1g IV infusion
    • Penicillin allergy = substitute cefazolin with vancomycin 1g IV infusion