Any Discipline

Question 1

1. What is an Abscess?

Answer 1

• Definition
  
  • Collection of pus (neutrophils, necrotic tissue, proteinaceous exudate +/- organisms) walled off by a zone of acute inflammation
• Formation
  
  • Response to pyogenic micro-organisms
    
    • Attract neutrophils
    • Resistant to phagocytosis and lysosomal destruction
  • Response to localized tissue necrosis
  • Organic foreign bodies (wood splinters)
• Common organisms
  
  • Staph Aureus
  • Strep pyogenes,
  • E.coli
  • Coliforms
  • Bacteriodes
• Outcomes
  
  • Eventually ‘point’ to nearby epitherlial surface and discharge contents.
  • If remote from surface à progressively enlarges causing tissue destruction.
    
    • Cellulitis
    • Systemic sepsis
    • “Bacterial showers” or Bacteremia à swinging pyrexia
  • If incomplete tx à chronic abscess à sinus or fistula formation.
  • Complete tx without drainage à ‘sterile abscess’ or ‘antibioma’
  • Organization and repair
    
    • Dead tissue removed by phagocytosis and defect filled by vascular connective tissue – Granulation tissue.
• Clinical presentation
  
  • swinging pyrexia
  • redness, cellulitis

Question 2

2. What is cancer Staging?

Answer 2

• Process of determining how much cancer is in the body and where it is located. Describes the severity of an individuals cancer based on the magnitude of the primary tumor and the extent to which it has spread through the body.
• TNM or four stages
• Some cancers have specific staging systems for sites.
• TNM (not for leukaemia, lymphoma or myeloma, brian or spinal tumors) – American Joint Committee on Cancer (AJCC)
  
  • Tumor size
    
    • TX – cannot be evaluated
    • T0 no evidence of primary
    • Tis – carcinoma in situ
    • T1-4 – size and/or extent of primary tumor
  • Node involvement 0-3
    
    • NX – cannot be evaluated
    • N0 – no regional lymph node involvement
    • N1-3 involvement of regional lymph nodes (number and/or extent of spread)
  • Metastases 0-1
    
    • M0 – no mets
    • M1 – distant mets
• Note: Grading is different to staging – it is the pathological assessment of a tumour to estimate the level of aggressiveness or level of malignancy based on the cytological differentiation and mitotic activity of the tumour. Grade I to IV in order of increasing anaplasia.
• Staging has proved to be of greater clinical value than grading

Question 3

3. What Modalities are used to stage cancer?

Answer 3

• Physical examinations: size & locations, lymph involvement
• Imaging tests:
  
  • X-rays, CT scans, and MRI scans, Barium studies, USS – size, location, Mets
• Blood tests:
  
  • FBC, LFTs, Tumor Markers
• Endoscopy
  
  • Upper GI, colonoscopy, ERCP
• Pathology Reports:
  
  • size of tumor, growth into other tissues, type of tissue cells and grade of tumor (how closely cancer cells resemble normal tissue).
  • Cytology/Histology:
    
    • Body fluids
    • FNA
    • biopsy
    • Immunohistochemistry
    • Cytogenic analysis
• Surgical reports:
  
  • size and appearance of tumor, lymph node and organ involvement

Question 4

4. What is the purpose of “staging” a patients cancer?

Answer 4

• Aids in develop a prognosis and treatment plan
  
  • Surgical/radiotherapy/hormone therapy
  • Curative vs Palliative
• Allows for evidence-based treatment due to comparison with trial data
• Common language to communicate and collaborate re:patients cancer
• Eligibility for clinical trials

Question 5

5. What is neoplasia? Give examples of benign and malignant neoplasms.

Answer 5

• Uncontrolled growth that persists after the initiating stimulus has been removed.
• Benign
  
  • slow growing, well demarcated, encapsulated, histology closely reminiscent of tissue of origin, localised to site of origin
  • adenoma, fibroma, lipoma, osteochondroma,
• malignant
  
  • ​progressive and rapid growth, poorly defined, irregular outline, non-encapsulated, local invasion and metastasize to parent tissue, anaplastic, pleomorphic.
  • carcinoma, sarcoma, teratoma, leukemia, lymphoma

Question 6

6. What is a fistula? Give some examples.

Answer 6

• abnormal connection of 2 epithelial surfaces, such as two hollow organs or between a hollow organ and the exterior
• They are lined by granulation tissue and colonised by bacteria
• The formation of a fistula requires inflammation and pressure
• Causes:
  
  • Inflammation
  • Infection - Abscess formation and spontaneous drainage
  • Trauma - Penetrating wounds
  • Iatrogenic – Surgical and radiation therapy
  • Neoplastic
  • Congenital
• Examples:
  
  • Rectovesical fistula – most commonly caused by diverticulitis
  • Crohn’s Disease:
    
    • Colocolic fistula
    • Gastrocolic fistula
    • Enterovesical fistula
    • Enterocutaneous fistula
  • Anal fistula – due to abscess rupture
  • Rectovaginal fistula – pelvic cancer/ treatment
  • Tracheo-oesophageal fistula – congenital
  • Causes of a non-healing fistula: (FRIEND)

F – Foreign Body

R – Radiation

I – Inflammation/ Infection

E – Epithelialisation

N – Neoplasia

D – Distal Obstruction

treatment

• drain and remove granulation tissue
• nutrition

Question 7

7. What is a stoma?

Answer 7

• Definition
  
  • Opening created between hollow viscus and the skin.
• Either ‘end’ (only one lumen brought to surface) or ‘loop’ – both ends
• Ileostomy - Right iliac fossa
• Colostomy – left iliac fossa
• Dehiscence – separation of the mucocutaneous junction
• Temporary or permanent
• Complications 56%

Question 8

8. What are the potential complications of a srugical procedure?

Answer 8

1. complications predisposed to by co-morbid ‘medical disorders’, wheather symptomatic or occult e.g. Ischaemic heart disease, chronic respiratory disease or diabetes mellitus
2. complications of anaesthesia
3. general complications of operations e.g. haemorrhage or wound infections
4. complications of any surgical condition e.g. pulmonary embolism, pneumonia, UTI, pressure sores
5. complications of specific disorders and operations e.g. bowel surgery - obstruction, peristalsis, failed anastomes, peritonitis, fistula.
   e. g. laparscopic, sub cut emphysema, cardiovascular collapse, haemorrhage,

Question 9

9. What are the risk factors for a superficial wound infection?

Answer 9

Patient related factors

• Advanced age
• Cigarette smoking, Malnutrition, High BMI
• Diabetes, Concurrent infection
• Impaired immune response (Immunosuppression, Prior site irradiation, Peripheral vascular disease)

Surgical factors

• Inadequate sterilization of surgical instruments, Foreign material in surgical kit, Microbial contamination, Surgical drains
• Preoperative shaving, Inadequate skin preparation
• Inappropriate selection of prophylaxis, Prolonged operation
• Poor operating room ventilation, Poor surgical technique

Question 10

10. How do you treat a superficial wound infection?

Answer 10

• Confirm SSI with history and examination
• Samples for gram stain and culture
• Surgical drainage and irrigation with 0.9% Saline
• Fluid absorbing dressing; consider antibiotics
• Mild to moderate
  
  • flucloxacillin or cephalexin
  • If gram neg suspected: amoxycillin + clavunate
• Severe (systemic):
  
  • flucloxacillin IV or vancomycin IV
  • If MRSA suspected: add vancomycin IV to above
  • If gram neg: add gentamycin IV
• If susceptibility testing not available by 72hrs and empirical IV therapy is still required, cease gentamixin regimen, and use pipercillin + tazobactam (Tazacin)

Question 11

11. What are the principles of antibiotic prophylaxis for surgical patients?

Answer 11

* Decide if prophylaxis is appropriate

• Determine the bacterial flora most likely to cause postoperative infection (not every species needs to be covered)
• Choose an antibiotic, nased on the steps above, with the narrowest antibacterial spectrum required.
• Choose the less expensive drug if two drugs are otherwise of equal antibacterial spectrum, efficacy, toxicity and ease of administration
• Administer dose at the right time
• Administer antibiotics for a short period (one dose if surgery of four hours duration or loss)
• Avoid antibiotics likely to be of use in the treatment of serious sepsis
• Do not use antibiotic prophylaxis to overcome poor surgical technique
• Review antibiotic prophylaxis protocols regularly as both cost and hospital antibiotic resistance patterns may change.
• IV bolus on induction of anesthesia
• Oral or rectal need to be given earlier

NPS

Question 12

12. Why do surgical wounds fail?

Answer 12

• Technical issues with close of the incision
  
  • Materials unsuitable to hold the edges and sides of incision together.
  • Suture knots slip/beak/unrave/cut through tissue
  • Too much/little tension
• Mechanical stress
  
  • Forced tension closure with inadequate tissue mobilization
  • Local oedema (infection/inflammation)
  • General oedema (CHF)
  • External trauma
  • Intra-abdominal and/or intra-thoracic pressure – coughing, retching, lifting weights etc
• Disrupted Healing
  
  • Local factors - ischaemia/hypoxia, infection/contamination, inflammatory conditions
  • systemic factors - chronic disease/comorbidities (Diabetes, CKD, immunosuppression), medication (corticosteroids, chemotherapy), radiotherapy, smoking, alcoholism, malnutrition, connective tissue disorders
  • poor compliance to treatment plan

Question 13

13. What is the difference between the tissue obtained by fine needle aspiration and a core biopsy?

Answer 13

• FNA = thin needle and stylet is used to aspirate a small amount of tissue and/or fluid from the area under investigation
  
  • Anaesthetic may or may not be used
  • Cytological evaluation
  • Sensitivity 95%
  • Less expensive
  • sampling problems (may miss cancer cells if the needle is not sampling from within the lesion)
  • Can’t distinguish between invasive and non-invasive lesions (i.e. DCIS vs invasive carcinoma)
  • Fewer complications and less invasive
• Core Biopsy = A larger, hollow needle is used to withdraw small cylinders (cores) of tissue from the area under investigation
  
  • Takes longer than FNA and local anaesthetic is used
  • Histological evaluation
  • Sensitivity 98%
  • yields tissue fragments allowing architectural features of the lesion to be identified (i.e. determine whether DCIS or invasive carcinoma)
  • Detect tumour markers
  • Better sample to detect hormonal receptors
  • Investigation of choice for evaluating microcalcifications

Question 14

14. Please look at these arterial blood gas results:

pH 7.30

PaO₂ 66mmHg

PaCO₂ 26mmHg

base excess -6,5

Lactate 9.4

What is a summary description of these results?

Answer 14

Metabolic acidosis with partial respiratory compensation

pH 7.30 Acidotic

Pa02 88mmHg Hypoxic

PaCO2 Hypocapnic

Lactate high- lactic acidosis

base excess negatic - metabolic acidosis

Question 15

15. Please look at these arterial blood gas results: pH 7.30, arterial blood gas results: pH 7.30, Pa O2 66mmHg, Pa CO2 26mmHg, base excess - 6.5, lactate 9.4. What causes a blood gas profile of this sort?

Answer 15

Lactic acidosis with hypoxaemia – imadequate oxygen delivery.

• Hypoventilation
• Diffusion limitation
• Shunt
• V/Q inequality

This pattern suggests severe shock with end organ failure

Compensation has occurred with hyperventilation to remove CO2

Does not yet meet the criteria for respiratory failure.

• Type 1 – Hypoxia (<60 mmHg) and Normo- or Hypocapnia (< 50 mmHg)
• Type 2 – Hypoxia (<60 mmHg) and Hypercapnia (> 50 mmHg)

Question 16

16. What is a deep vein thrombosis?

Answer 16

• Blood clot develops within a deep vein of the leg
• 90% in calf
• Pain, swelling and tenderness in one leg, warmth in the area of the clot

Question 17

17. Why is a DVT important?

Answer 17

• 1 in 10 people with a DVT will develop a PE à lung collapse à RHF
  
  • Or chronic thromboembolic pulmonary hypertension
• Or DVT post-thrombotic syndrome
  
  • Chronic leg swelling and discomfort due to damage to the venous valves
  • Skin ulceration if severe

Question 18

18. What are some risk factors for hypercoagulability?

Answer 18

• Hereditary
  
  • Factor V Leiden
  • Elevated factor VIII
  • Antithrombin III deficiency
  • Prothrombin mutation
  • Hyperhomocystinemia
  • Protein S deficiency
  • Protein C deficiency
• Acquired
  
  • Previous DVT
  • Trauma and surgery
  • Increasing age
  • Venous stasis during general or regional anaesthesia
  • Malignancy
  • Immobility
  • Cardiac failure
  • High-oestrogen OCP, tx, HRT
  • Pregnancy
  • Obesity
  • dehydration

Question 19

19. How can the risks of a DVT be reduced in a surgical patient?

Answer 19

• General measures
  
  • Early post-op mobilization
  • Adequate hydration
  • Avoiding pressure on the calves
• Prophylactic measures
  
  • Low-dose subcut heparin
  • Oral direct factor XA inhibitors – rivaroxaban
  • Calf-compression devices
  • Graduated compression ‘anti-embolism’ stockings
  • Warfarin anticoagulation

Question 20

20. What is Virchow’s Triad?

Answer 20

• Abnormalities in the vein wall (trauma, inflammation)
• Alterations in blood flow (stasis)
• Changes in blood (hypercoagulability)

Question 21

21. You are the general surgery resident on call. You are asked to review a 70 year old man who is 72 hours post elective, uncomplicated colonic surgery. He has developed an acute confusion having been well and behaving normally since surgery. What are you going to do?

Answer 21

• Phone call
  
  • In what way were they confused? GCS?
  • Vital signs?
  • what has been tried so far?
• Bedside
  
  • if unconscious - ABCDE, call for senior help
  • determine if delirious with Confusion Assessment Method
  • ask if in pain?
  • look for hx or signs of hypoxia, hypotension, sepsis, seizures, intraranial mass lesion
• Physical Examination
  
  • Vitals and GCS – also perform Abbreviated Mental Test Score (AMTS) or Quick Confusion Scale
  • HEENT – nuchal rigidity, photophobia, pupil size and symmetry, fundoscopy, otoscopy
  • Neuro – focal neurological deficit (esp. cranial nerve or motor deficit)
  • CVS – JVP, S3, pitting oedema, new murmur
  • Resp – cyanosis, respiratory distress, wheeze, crackles
  • Abdo – NG tube output, costovertebral angle tenderness, guarding, rebound tenderness, jaundice, hepatomegaly, asterixis
  • GU – Urine output from catheter
• Inv:
  
  • FBC, UEC, BSL, CMP, LFT
  • Blood cultures (if sepsis considered)
  • Urinalysis and urine MCS
  • ECG & CXR
  • Consider ABG (if respiratory cause considered
• treat cause
• reorientate patient, close observation, well lit room, clocks visible, have family present
• avoid using sedatives
• last resort use haloperidol, risperidone or olanzapine

Question 22

22. You are the general surgery resident on call. You are asked to review a 70 year old man who is 72 hours post elective, uncomplicated colonic surgery. He has developed a fever of 38.2 degrees C, having had no fever recorded since surgery. What are you going to do?

Answer 22

• phone call
  
  • Vitals, associated symptoms, immunosuppressed?
• bedside
  
  • ABCDE, call superior
  • consider sepsis, review chart
• 5W’s of Post-Op Fever
  • Wind (24 - 48hours) – i.e. pneumonia
    
    • Predisposed by instrumentation in airway, inadequate pain relief etc.
  • Water (3 - 5 days) – i.e. UTI
    
    • Especially if urinary catheter is in place
  • Walking (4 - 6 days) – i.e. VTE
    
    • Due to stress response or immobilisation
    • Patient should have prevention
  • Wound (5 - 7 days) – i.e. SSI
    
    • Also think about intra-abdominal and intra-thoracic
  • What did we do? (7+ days) – i.e. iatrogenic causes
    
    • Medication reaction
    • Blood transfusion reactions
    • Cannula site infection
• physical examination
  
  • Repeat vitals
  • General appearance
  • Mental status
  • HEENT – neck stiffness, photophobia, Kernig’s sign, Brudzinski’s sign, fundoscopy, otoscopy, sinus tenderness, oral inspection
  • CVS – pulse volume, skin temperature and colour, murmur
  • Resp – crackles, friction rub, bronchial breathing
  • Abdo – tenderness, jaundice, costovertebral angle tenderness, ascites, rectal tenderness or mass
  • Skin – erythema, tenderness, petechiae or purpura, dehiscence or signs of infection
• investigations
  
  • FBC, UEC, CRP
  • Urinalysis and Urine MCS
  • CXR and sputum MCS (if present)
  • Wound MCS (if purulent discharge)
  • Blood cultures x 2
  • DVT USS
• management
  
  • treat underlying cause
  • Sepsis
    
    • 3 In:
      
      • O₂ to keep saturation > 94%
      • IV antibiotics (if no focus evident - Flucloxacillin + gentamicin, otherwise treat most likely organisms)
      • IV fluids
    • 3 Out:
      
      • Blood cultures x 2
      • Serum lactate
      • Urine output
    • Supportive care – analgesia, antiemetics
    • Discontinue any fever inducing medications
    • Ensure VTE prophylaxis

If the patient has febrile neutropenia the use piperacillin + tazobactam 4g + 0.5g IV, 6 hourly

Question 23

23. You are the general surgery resident on call. You are asked to review a 70 year old man who is 12 hours post elective, uncomplicated colonic surgery. He has developed an acute episode of hypotension, which has persisted for 10 minutes. What are you going to do?

Answer 23

• MET call criteria:
  
  • < 100 SBP is yellow – requires clinical review (clinical judgement)
  • < 90 SBP is red – requires rapid response (MET call)
• Causes of hypotension:
• Shock – hypovolaemic, cardiogenic, distributive, or obstructive
• Medications (often postural) – antihypertensives, nitrates, sedatives, analgesics
• Autonomic neuropathy – DM, Parkinson’s disease, MSA
• Vasovagal attack
• Constitutional – some patients normally have a low BP

review patient immediately

• Phone call:
  
  • Vitals, GCS, clammy/pale, dyspnoea/chest pain
  • signs of bleeding, or rash?
  • medications in last hour? (anaphylaxis)
• Bedside
  
  • ABCDE, repeat vitals, manual BP, GCS
  • resus with IV crystalloids
  • tx apparent cause
  • selective hx (cardio, resp, general)
  • ECG, CXR
• Physical Examination – selective examination (Is there shock? What is the cause of the hypotension? Is the patient bleeding?)
  
  • Vitals (HR, BP, RR, SaO₂, Temperature)
  • HEENT – dry mouth (hypovolaemia)
  • Skin – temperature, colour, sweating, turgor, rash
  • CVS – Pulse, capillary refill, JVP, HS
  • Resp – Stridor, expansion, percussion (resonance, dullness) and auscultation (wheeze, crackles)
  • GIT – tenderness, peritonism, masses (pulsatile?), rectal bleeding (PR exam)
  • CNS – orientation, confusion, agitation
  • GUT – urine output
  • Other – NGT output, wound sites
• Investigations
  
  • FBC, UEC, LFT, Coagulation studies, Cross match, VBG (?ABG), ? blood cultures
  • ECG
  • CXR
  • Urinalysis (? Urine MCS if abnormal)
  • ? USS (AAA, pericardial tamponade, ectopic pregnancy, intraabdominal haemorrhage)
  • ? Echo
  • ? serum troponin
  • ? D-dimer
• Management:
  
  • Treat any underlying cause identified
  • Give IV crystalloids for resuscitation
  • Consider giving blood products if the patient is bleeding
  • Review the patient regularly

Question 24

24. You are the general surgery resident on call. You are asked to review a 70 year old man who is 24 hours post elective, uncomplicated colonic surgery. His Urine output has dropped from an average of 60mls per hour (>1/2 ml per kg) in the first 24 hours to 20 mls per hour for the last 2. What are you going to do?

Answer 24

• Oliguria is variably defined as < 400mL/day, < 0.5mL/kg/hour, or < 20mL/hour
• Anuria is the complete absence of urine output
• Patients with pain, hyperkalaemia, acidosis, or signs of fluid overload should be seen urgentl

Phone Call:

• Is the patient complaining of abdominal pain?
• vital signs?
• Indwelling urinary catheter? ask the nurse to flush the catheter with 20-30mL of normal saline to dislodge sediment or clots and restore patency
• Also request an ECG
• Let the nurse know that you will come and assess the patient (don’t give phone orders for a fluid challenge)

Bedside:

• Immediate Management:
  
  • Assess ABCDE
• Review – observation chart, fluid balance chart, medication chart, patient notes
• History:
  
  • Is the patient thirsty? Does he feel the need to urinate? Does he have a history of renal disease?
  • Is he in pain?
  • Has he had an haematuria, frothy urine, swollen ankles, rashes or arthralgia?
  • Did he have any urinary symptoms before hospital?
• Physical Examination:
  
  • Vital signs & mental status
  • Skin – temperature, colour, sweating, turgor, rash
  • HEENT – jaundice (hepatorenal syndrome), dry tongue and mouth
  • CVS – Pulse, capillary refill, JVP, HS
  • Resp – expansion, percussion (dullness) and auscultation (basal crackles)
  • Abdo – bladder size, enlarged kidneys, tenderness, peritonism, intraabdominal haemorrhage, PR exam (bleeding, enlarged prostate)
• Investigation:
  
  • FBC, UEC, coagulation studies, VBG (? ABG), blood glucose, consider blood cultures
  • ECG
  • Bedside bladder scan (USS)
  • Urinalysis and Urine MCS
  • Consider abdominal/ pelvic USS
• Management:
  
  • If hypovolaemia is suspected than a fluid challenge is appropriate:
    
    • 250 - 500mL of crystalloids IV stat (i.e. under gravity, fast flowing)
    • Hartmann’s is the fluid of choice if there are now electrolytes results available
  • Continue to closely monitor the urine output and vitals
  • Review the patient yourself in 30 mins:
    
    • A rise in urine output and BP suggests adequate treatment
    • If further deterioration or only a short response then call your registrar and potentially involve MET or ICU team

Major Threats to life:

• Hypotension and shock
• Oliguric acute renal failure
• Sequelae of acute renal failure
  
  • Hyperkalaemia
  • Metabolic acidosis
  • Acute hypertension
  • Pulmonary oedema

Question 25

25. What are the Sypmtoms and Signs of a PE?

Answer 25

Symptoms

Signs

• Dyspnea
• Pleuritic chest pain
• Cough
• Hemoptysis
• Dizziness
• Syncope
• Tachycardia
• Signs of a DVT
• Pyrexia
• Cyanosis
• Tachypnoea
• Hypotension
• Raised JVP
• Pleural rub
• Pleural effusion

Inv:

• ABG
  
  • decr. PaO₂ and decr. PaCO₂
• ECG
  
  • Sinus tachycardia (most common)
  • RV strain (inverted T wave in V1-4)
  • New onset RBBB
  • S1Q3T3 pattern (rare)
• CXR
  
  • Often normal
  • Prominent hilar vessels
  • Oligaemic lung fields
  • Linear atelectasis

Question 26

26. How is a PE diagnosed?

Answer 26

• Wells Criteria
  
  • Modified Wells
• D-dimer rules out in low-to-moderate likelihood PE
  
  • Degradation product of cross linked fibrin in thrombi.
• Elevated troponins, BNP
• ECG S13T3 sign
• CXR
• Chest CT with IV contrast
• CTPA
• Ventilation-perfusion scan (2^nd line)

Question 27

27. How is a PE treated?

Answer 27

• Initial:
  
  • Oxygen – maintain SpO2 >90
  • Analgesia
  • Hemodynamic support IV fluids
• Acute anticoagulation tx for proximal DVT and PE
  
  • APTT, INR, FBC, Kidney Function, LFT, hCG (women of childbearing age)
  • NOACs (except pregnancy and malignancy)
    
    • Oral factor Xa inhibitors( apixaban or rivaroxaban)
• Haemodynamically unstable pts:
  
  • Fibrinolytic therapy (Alteplase/Tenecteplase)
  • Catheter-directed fibrinolytic therapy
  • Thrombus aspiration
  • Surgical thrombectomy
• Anticoagulation regimes:
  
  • Do not dissolve existing clots but limits further thrombus formation and allows finrinolysis
  • Parental therapy with transition to warfarin (INR daily)
  • Parenteral therapy with transition to oral anticoagulant such as dabigatran or edoxaban
  • Oral anticoagulation with rivaroxaban or apixaban without parenteral anticoagulation
  • UFH
    
    • Requires intensive lab monitoring
• Duration of therapy:
  
  • Major provoking factor that is no longer present, tx for 3months
  • Isolated distal DVT caused by major provoking factor that is no longer present, tx for 6 wks.
  • Unprovoked – evidence points towards <3mo
• Assess risk of bleeding
  
  • Prior bleeding,
  • Active Peptic ulcer disease
  • Oesophageal varices
• Predictive factors of recurrence
  
  • Prior VTE
  • Active cancer
  • Unprovoked VTW (no sugery, medical illness with reduced mobility, trauma, oestrogen therapy)
  • Male sex
  • Proximal DVT or PE (rather than distal)
  • Certain thrombophilia’s (antithrombin deficiency, protein C or S deficiency)
• Extended anticoags
  
  • Multiple prior unprovoked episodes of DVT or PE
• Continue with full dose of anticoagulant therapy

Question 28

28. What is a pulmonary embolism?

Answer 28

• Obstruction in/on pulmonary artery or one of its branches by material (thrombus, tumor, fat, air) that originated somewhere else in the body.
• Infarction is more likely if the embolus completely blocks a large artery or if there is pre-existing lung or heart disease

Question 29

29. What are the factors that increase the risk of formation of a DVT?

Answer 29

• Virchow’s triad
  
  • Endothelial injury
  • Stasis (immobility, dec. flow, inc. viscosity)
  • Hypercoagulability (inherited or acquired)
• Risk factors
  
  • Age
  • Surgery
  • Immobilization/prolonged hospitilisation
  • Past hx of VTE
  • Trauma
  • OCP/HRT
  • Pregnancy
  • Thrombotic disorders
  • Malignancy
  • Obesity
  • Cardiorespiratory disease (COPD, CHF)
  • Smoking

Question 30

30. What are the important contra-indications for a patient to have an epidural catheter placed for analgesia?

Answer 30

• Absolute
  
  • Infection at site of injection
  • Lack of consent
  • Coagulopathy or other bleeding diathesis
  • Severe hypovolemia
  • Increased ICP
  • Allergy to anaesthetic
• Relative
  
  • Sepsis
  • Uncooperative patient
  • Preexisting neurological deficits
  • Demyelinating lesions
  • Stenotic valvular heart lesions
  • Left ventricular outflow obstruction (hypertrophic obstructive cardiomyopathy)
  • Severe spinal deformity
  • Coagulopathy
  • Platelet <100,000
  • Positioning problems
• Controversial
  
  • Prior back surgery at the site of injection
  • Complicated surgery
  • Prolonged operation
  • Major blood loss
  • Maneuvers that compromise respiration

Question 31

31. What are the common or important complications and side effects of an epidural anaesthetic?

Answer 31

• Adverse or exaggerated physiological responses?
  
  • Urinary retention
  • High block
  • Total spinal anesthesia
  • Cardiac arrest
  • Anterior spinal artery syndrome
  • Horner syndrome
• Complications related to the needle/catheter placement
  
  • Back ache
  • Dural puncture leak (headaches, diplopia, tinnitus)
  • Neural injury (nerve root damage, spinal cord damage, cauda equina syndrome)
  • Bleeding (intraspinal/epidural hematoma)
  • Misplacement
    
    • No effect/inadequate anesthesia
    • Subdural block
    • Inadvertent SA Block or intravascular injection
  • Catheter shearing/retention
  • Inflammation – arachnoiditis
  • Infection (meningitis, epidural abscess
• Drug toxicity
  
  • Systemic local anesthetic toxicity
  • Transient neurological symptoms
  • Cauda equina syndrome
• others
  
  • Incomplete blockade
  • Hypotension (due to the sympathetic block).

Question 32

32. What is the treatment of hypotension that is occurring in a patient who has an epidural anaesthetic in place? The patient is 12 hours post laparotomy at which a left hemicolectomy was done?

Answer 32

• Vasopressors + IV fluids
• Neuroaxial blockade causes symptathetic blockade. This leads to systemic vasodilation and a reduced TPR as well as decreased venous return
• Management:
  • Stop the epidural infusion and call for help (including notifying the anaesthetist)
  • Perform ABCDE:
    
    • Assess airway and the need for ventilation support
    • Give supplemental oxygen if SpO₂ < 92%
    • Gain IV access
      
      • Fluid bolus
      • IV vasopressors (should only be used by ICU trained staff) e.g. NA, metaraminol
    • Perform and ECG
    • Assess LOC
    • Check temperature (e.g. sepsis)
  • Targeted history and examination
    
    • Chest pain, dyspnoea, haemoptysis
    • Cardiorespiratory examination
    • Peritoneal signs (? intraabdominal haemorrhage)
• Hypotension may be:
  
  • Absolute (SBP < 90 mmHg)
  • Relative ( in SBP by > 40 mmHg)
  • Orthostatic ( in SBP by > 20 mmHg or DBP by > 10 mmHg)
  • Profound (requiring vasopressors)
• Accidental intrathecal injection leads to total spinal anaesthesia:
  
  • Hypoperfusion of medulla
  • Respiratory depression
  • Loss of consciousness

Question 33

33. What, chemically, is in a 1L bag of ‘normal saline’? What is the average daily sodium requirement for a 70kg man?

Answer 33

0.9% sodium chloride

• 154mmol Na
• 154 mmol Cl
• Osmolarity = 308mOsm/L

Daily sodium requirement = approx. 1mmol/kg/day

• 70 kg man = 70 mmol Na/day
• 1L saline daily satisfies the daily sodium needs
• Diet: 150mmol/day (50-300)

Usual losses

• Stool – 5mmol/day
• Skin transpiration 5mmol/day
• Urine 140mmol/day

Question 34

34. What is the adult sodium requirement? what is the daily potassium requirement?

Answer 34

Daily sodium approx. 1mmol/kg/day

• GIFTASUP recommend 50-100 regardless of weight

Daily potassium approx. 1mmol/kg/day

• GIFTASUP recommend 40-80mmol/day in 1.5-2/5L of water
• Diet 100mmol/day (50-200)

Usual losses:

• Stool 10mmol/day
• Skin <5mmol/day
• Urine 85mmol/day

Question 35

35. What is the adult daily potassium requirement? How do you usually prescribe this for IV infusion?

Answer 35

• Daily potassium approx. 1mmol/kg/day
  
  • GIFTASUP recommend 40-80mmol/day in 1.5-2/5L of water
• Prescribed in pre-loaded bags
  
  • 30mmol potassium chloride in normal saline
  • 30mmol potassium chloride in 5% dextrose
  • 30mmol potassium chloride in Hartmann’s solution
• Bags containing potassium are pink/red
• No abbreviations in charting
• Maximum rate must not exceed 10mmol/hr unless in HDU/IDU setting.
• Potassium should not be administered as bolus or rapid infusion due to risk of cardiac arrhythmias
• Must have rate limiting device such as infusion pump

Question 36

36. What is the adult water volume requirement per day? How would you prescribe this in IV orders to someone who is nil by mouth?

Answer 36

NICE guidelines state - daily water requirement for maintenance fluids:

• 25 – 30 mL/kg/day
• For a 70kg patient this is 1750 – 2100 mL over a 24-hour period
• GIFTASUP states that patients should receive 1.5 – 2.5 L of water/ day
• Assuming that the patient who is NBM only requires maintenance fluids:
  
  • 0.18% NaCl + 4% dextrose + 30 mmol KCl in 1L bag x 2
    
    • then
  • 0.18% NaCl + 4% dextrose
• Infusion rate of 100mL/hr would deliver 2.4L of water, 72 mmol sodium, 60 mmol potassium, 72 mmol chloride, and 96g of dextrose over a 24-hour period

Question 37

37. Please write out a fluid prescription for 24 hours “maintenance” fluids for a patient who weighs 90kgs, has no unusual insensible or measureable losses.

Answer 37

• Water requirement: 80kg x 25-30mL/kg/day = 2000mL – 2400mL
• Sodium requirement: ~80mmol/day
• Potassium requirement ~80mmol/day
• Chloride requirement ~80mmol/day
• Glucose requirement 50-100mmol/day

Regimen:

• Bag 1: 1L 0.18% NaCl + 4% Dextrose + 30mmol KCl
• Bag 2: 1L 0.18% NaCl + 4% Dextrose + 30mmol KCl
• Bag 3: 1L 0.18% NaCl + 4% Dextrose

Infusion rate of 100mL/hr

• 2.4L water, 72mmol sodium, 72 mmol chloride, 60mmol potassium, 96g dextrose over 24hours

Question 38

38. What chemically is in a 1L bag of Hartmanns solution?

Answer 38

• 1L of H2O
• 131mmol of Na+
• 111 mmol of Cl-
• 29mmol lactate (HCO3)
• 5 mmol of K+
• 2 mmol of Ca2+
• Osmolarity = 278mOsm/L

Question 39

39. What, chemically, is in a 1L bag of 1/5 Saline, 4% dextrose?

Answer 39

4% and 1/5

• 1L of H20
• 30mmol of Na+
• 30mmol of Cl-
• Osmolarity = 284mOsm/L

Question 40

40. What are the common or important immunological complications of a blood transfusion?

Answer 40

• acute <24hr
  
  • Acute Haemolytic Transfusion Reaction (AHTR)
  • Febrile Non-Haemolytic Transfusion Reaction (FNHTR)
  • Allergic Reactions
  • Transfusion Related Acute Lung Injury (TRALI)
• Chronic >24hrs
  
  • Delayed Haemolytic Transfusion Reaction (DHTR)
  • Post-transfusion purpura
  • Transfusion Associated Graft vs. Host Disease (TA-GvHD)
  • Transfusion Related Immune Modulation (TRIM)
• potentially fatal
  
  • AHTR & DHTR
  • Allergic Reactions (anaphylactic)
  • TRALI
  • FNHTR (rarely)
  • Post-transfusion purpura (rarely)

Question 41

41. What are the common or important non-immunological complications of a blood transfusion?

Answer 41

• Acute <24hrs
  
  • Complications of massive transfusion
  • Non-immune mediated haemolysis
  • Transfusion transmitted bacterial Infection (TTBI)
  • Transfusion Associated Circulatory Overload (TACO)
• Chronic >24hrs
  
  • Iron Overload
  • Transfusion transmissible infections
• Potentially fatal
  
  • Complications of massive transfusion
  • TTBI
  • TACO