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					                   Principles of Surgery
Blood transfusion
Workup

      Infections screened for: HBV, HCV, HIV1/2, Syphillis + CMV in
       immunocompromised
      Adult blood volume = 70mls/kg
      Paediatric blood volume = 80mls/kg



Product          Storage / Half-lifeNotes                  Indications
Packed red cells 280mls             Additive solutions:    Anaemia
                 Stored at 2-6'C    suspend cells          Restore circulatory volume
                 35 days (normal    CAPD: citrate-         Improve tissue oxygen
                                    adenine-phosphate-
                 red cell life is 120                      perfusion (by maintaining
                 days)              dextrose               oxygen carrying capacity)
                                    SAMG: saline-
                                    adenine-mannitol-
                                    glucose
                                    Dosing: 4ml/kg
                                    raises [Hb] by 1g/dl
Platelets       Stored at room      Platelets are pooled   Thrombocytopenia < 50 x
                temperature on      as one donation        10 9
                agitator (prevents normally contains       DIC
                clumping)           ~55 x109               Post bypass / dysfunctional
                5-7 day life        Risk of infection      platelets
                                    Rhesus sensitisation
Cryoprecipitate Stored at -30'C     Factors V / VII are    Reversal of warfarin
/ FFP           12 month shelf-life most labile to         Post massive transfusion
                                    temperature            DIC / loss of clotting
                                    Dosing: 10-            factors
                                    15mls/kg
                                                           Ascities / portal
                                                           hypertension
Human            4.5% or 20%
                                                           Oedema due to
Albumin          solution
                                                           hypoalbuminaemia
                                                           Plasma expander



Complications of transfusion

   1. Immediate
            o Temperature changes - from pyrogens (from dead polymorphs,
              endotoxins)
           o Immune reactions
                  1. Type I: Immediate - Anaphylactic reaction
                  2. Type II: Cytotoxic -
                  3. Type IV: Delayed
           o Infection - gram -ve organisms (coliforms, pseudomonas)
           o Metabolic - hyperkalaemia (haemolysis); hypocalcaemia (citrate
              antocoagulation), acidosis
           o Circulatory - hypervolaemia: massive transfusion reaction =
              "transfusion equalliny patient's blood volume within 24 hours"
           o Bleeding diathesis - deficient in platelets (thrombocytopenia) and
              clotting factors
     2. Delayed
           o Sensitisation to antigens
           o Infection from unscreened blood - HBV, HCV, HIV, CMV, syphilis,
              malaria
           o Fe-overload: heart, pancreas

Or

     1. Massive transfusion: Transfusion equallying patients blood volume within 24
        hours
            o Volume overload - Pulmonary oedema
            o Thrombocytopaenia
            o Coagulation factor deficiency
            o Hypothermia
            o Hypocalcaemi: chelation by citrate in additive solution
            o Hyperkalaemia: progressive potassium leakage
     2. Repeated transfusion
     3. Infective complications
            o HBV, HCV, HIV
            o Syphilis
            o Yersinia enterocolitca -
     4. Immune reactions
            o Febrile reactions: white cell antigens, reaction within one hour
            o Acute haemolytic reaction: ABO incompatability
            o Delayed haemolytic reaction: immunised to foreign red cell antigen
                due to previous exposure. Leads to jaundice/haemolysis later
            o Post transfusion purpuric reaction
            o Graft vs host disease
            o Anaphylactic reactions




Management

     1. Stop transfusion
     2. Resuscitate
     3. Repeat G+S
   4. Perform direct anti-globulin test (Coomb's test) on post-transfusion sample;
      antibodies against surface antigens
   5. Check for haemolysis (bili, K); DIC (FDPs, haemoglobinuria)
   6. Blood cultures


Acute Limb Ischaemia

Aetiology

   1. Embolus: commonest
   2. Thrombosis: pre-existing stenosis, aneurysm or occlusion
   3. Trauma

Presenting Features

   1.   Pale
   2.   Pain
   3.   Parasthesia
   4.   Pulseless
   5.   "Perishingly cold"
   6.   Paralysed

Management

   1. History
            o   Onset / duration
            o   Risk factors: peripheral vascular disease, cardiac disease
   2.   Examination
            o Cardiovascular exam
            o AAA
            o Examine limb - sensation, motor function, pulses; compare with
                contralateral limb
   3.   Investigations
            o Hand-held doppler flow
            o Arterial doppler
            o (If "threatened" - angiogram)
            o Determine source of embolus - cardiac (electrolytes, ECG, echo)
   4.   Treatment
            o Resuscitation - oxygen, IV fluids, analgesia
            o IV heparin - prevent thrombus propagation
            o Salvagable: embolectomy, bypass
            o Consider thrombolysis (with tPA - tissue plasminogen activator)
            o Unsalvagable: amputation
   5.   Post-operative
            o Continue anticoagulation (1) Heparin (2) Warfarin for 3 months
            o Continue resuscitaiton
            o Physiotherapy
            o Protect limb
Anastamosis

Definition
"Without mouth" - Joining of one viscus/vessel with another to establish continuity of
flow



Types

   1. End-to-end
   2. End-to-side (differing sizes of lumens)
   3. Side-to-side




Uses        Examples      Notes

Gastrointest Colorectal   Two layer technique (classical teaching)
inal         Enterocolost
             omy            1. Full-thickness "all coats" continous suture - catches
                                strong submucosa
                            2. Seromuscular interrupted suture (Lembert stitch)

                          - Achieves inversion (low likelihood of anastamotic leakage)
                          - Inner layers haemostatic but prone to stangulation

                          Single layer technique (modern teaching)

                              1. Interrupted seromuscular extramucosal suture on round-
                                 bodied needle

                          - Minimal damage to vascular plexus
                          - may cause less tissue trauma

                          Stapled

                              1. Linear: creates side-to-side anastamosis
                                     o Inserts 4 parallel linear rows and cuts in the
                                          middle
                              2. Circular:
                                     o Unites bowel end-to-end
                         - Reduced anastamotic leakage
                         - Increased strictures

                         Tissue Glue



                         Suspection of leakage

                             1. Unexplained pyrexia
                             2. Tachycardia
                             3. Prolonged ileus
                             4. GI contents in drain

Urology     Uretero-      Use absorbable sutures (non-absorbable causes stones)
            ureterostom
            y
            Ureteric
            bladder re-
            implantation
            Ileal conduit
            / ileal pouch

Vascular / Coronary       Aim:
Cardiothora artery
cics        bypass grafts    1. Permanently establish flow
            Fem-pop          2. Avoid intimal disruption and turbulence
               bypass                     o    Pass needle within outwards
                                          o    Smooth intimal suture line
                                          o    Eversion of anastamosis

                              Use non-absorbable suture

                              - Everted anastamosis (provides intact endothelial surface,
                              low risk of thrombus)



                              Complications

                                 1. Bleeding / leakage / pseudoaneurysm
                                 2. Stenosis
                                 3. Thrombosis
                                 4. Distal embolism

Transplant     Renal
               transplant
               Liver
               transplant

Plastic        Microvascula
surgery        r
               anastamosis




Factors for successful anastamosis

           Blood supply
Local      Tension-free
           Good approximation
           No distal obstruction
           Resuscitated, warm, well perfused
Patient
           Good nutrition

           Appropriate sutures
Surgical
           Avoidance of watershed areas



Brainstem death

Definition
      Irreversible cessation of all functions of the brain
      Loss of capacity for consciousness and for ventilation (brainstem)

Criteria for diagnosis of brainstem death

   1. Apnoeic coma of known aetiology - must exclude metabolic (hyglycaemia,
      hypothyroid), drug intoxication, hypothermia
   2. Absent cranial nerve reflexes - pupillary (II, III), corneal (III, V), vestibulo-ocular,
      pharyngeal (IX, X), bronchial (X)
   3. Absent motor response to painful stimuli within cranial nerve distribution
   4. Absence of spontaneous respiration with permissive hypercapnoea (PaCO2 > 8kPa)
      following oxygenation

Tests should be performed on 2 separate occassions by 2 medical practitioners
registered for more than 5 years (and competent in field).
Tests should not be performed by members of the transplant team
(Difficult to perform in brainstem encephalitis, ocular trauma)



Physiological Changes in Brainstem death

   1. Loss of pituitary function
          o Loss of vasopressin / ADH release - diabetes insipidus, hypernatraemia,
               small brain cells; 4ml/kg/hr urine loss - corrected temporarily with IV
               dextrose +/- aAVP infusion
          o Loss of anterior pituitary hormone production
                    TSH loss; hypothyroidis
   2. Loss of temperature regulation at hypothalamic level
          o Hypothermia, exacerbated by loss of motor/metabolic activity - managed by
               warming
          o Coagulopathy
   3. Disorderd autonomic system
          o Initial hypertension - immediate increase in sympathetic activity
          o Hypotension from loss of sympathetic vascular tone



Burns

Burn

Coagulative necrosis of tissue result from thermal (heat/cold), electrochemical or
radiation injury

      Heat
      Cold
      Electrical burns
      Chemical burns
      Radiation burns

Assesment of burns
    1. Extent (size)
           o % body area: Wallace's rule of 9s
           o Hand = 1%
    2. Depth
           o Superficial - epidermis (painful: erythema, no blistering, heal within 2-5
               days)
           o Partial thickness - epidermis and variable amounts of dermis (painful:
               erythema, blistering)
           o Full thickness - all of dermis (painless, white/waxy)




Criteria for referral to Burns unit:

    1. Patient
            o    Extremes of age
    2. Burn
            o    Size >15% (10% paediatric)
            o    Location: hands/feet/perineum
            o    Circumferential burns (requiring escharotomy to prevent ischaemia and
                 necrosis)
            o    Electrical burns (risk of rhabdomyolisis)
Management

   1. Airway/Breathing
          o Resp distress / high flow oxygen
          o Early intubation and support
   2. Circulation
          o Monitor fluid therapy

                ATLS guideline: 2-4mls/kg/%burn in 24 hours: give half in first 8
                hours, half over remaining 16 hours (Modified Parkland Formula)

                Mount vernon: Weight x%burn/2

            o    Central venous line
            o    Urinary catheter
   3.   Disability
            o Assess wound size
            o Cover wounds + tetanus prophylaxis
            o Renal support
            o Analgesia
   4.   Exposure
            o Warm
            o Stress ulcer prophylaxis
   5.   Surgery - constricting circumferential thoracic eschars
   6.   Nutritional supplementation commenced early
   7.   Priority areas for skin grafting - eyelids (prevents ectropion), face, hands, joint
        flexures




Complications

   1. Respiratory: fire in confined space, soot in mouth/sputum, hoarse voice, >10%
      serum carboxyhaemoglobin
          o Thermal injury to nose / oropharynx with upper airways oedema
          o Smoke inhalation can lead to hypoxia and pulmonary oedema from ARDS
          o Toxic gases: carbon monoxide (250 more affinity for Hb), cyanide, sulphur,
              nitrogen
   2. Shock
          o Plasma protein loss (loss of skin cover)
   3. Renal failure
          o Hypovolaemia from plasma protein loss reduces renal perfusion + ATN
          o Myoglobin (from muscle) produces rhabdomyolysis and results in ATN
   4. Electrolyte disturbance
          o Hypo/hypernatramia
          o Hypo/hyperkalaemia
   5. Hypothermia
          o Loss of skin cover
   6. SIRS / Sepsis
   7. Gastric ulcers
          o Curling's ulcers (cf Cushing's ulcers) as part of stress response
   8. Coagulopathy
         o Due to DIC



Chemotherapy

Aims of Chemotherapy

   1. Cure
   2. Prevention (of recurrence)
   3. Shrink tumours

Types

   1.   Primary
   2.   Neoadjuvant - before surgery (eg shrink breast cancer)
   3.   Adjuvant - after surgery to gain control of primary disease
   4.   Palliative

Considerations

   1.   Chemosensitivity
   2.   Stage
   3.   Grade
   4.   Patient's health

Principles of treatment

       Adjusted according to weight and height
       Body surface area estimated and cycles given at intervals to allow the body normal
        tissue to recover
       High dose chemotherapy indicated in otherwise fit patients where cure may be
        achieved (choriocarcinoma, leukaemia) - but can cause profound toxic effects on
        bone marrow [possible to use stem cells support now]

Classification of Cytoxic agents

   1. Alkylating agents - impair function of enzymes to form DNA: chlorambucil /
      cyclophosphamide
   2. Anti-metabolites - irreversibly interrupt DNA: Methotrexate / 5FU
   3. Vinca alkaloids - inhibit microtubule function: vincristine / vinblastine
   4. Anti-mitotic agents: cause damage by production of free radicals


Clinical Trials / Medical statistics

Scientific method of detecting differences between treatments
Detect merits of specific treatments for patients with specific diseases
Provide evidence of efficacy and safety
Ethics behind clinical trials (declaration of Helsinki 1961)

   1. Patients should not be denied effective treatments
   2. New treatment must be safe (no patient should suffer as part of a trial)




Pre clinical trials

       Assess toxicity / pharmacology of drug
       In vitro / in vivo testing




Clinical Trials

       Phase I: Normal healthy volunteers - to assess correct pharmacological dosing, route
        of administration (<20 patients)
       Phase II: Select subpopulation of patients, establish efficacy; resource assessment, if
        not helpful would not be ethical to proceed (-100 patients)
       Phase III: "Normal patients" (1000s) - establish efficacy and safety
       Phase IV: Pos-marketing surveillance




Controlled clinical trial

       Active treatment compared with control treatment (may be placebo, current
        standard, etc)
       Used to determine the best course of treatment

Clinical trial protocol

   1.   Introduction
   2.   Aims + hypothesis / precise question asked
   3.   Materials
   4.   Methods: end points
   5.   Results
   6.   Statistics
   7.   Bibliography
   8.   + Financial support, responsibilities of workers, signatures




Error / null hypothesis

Null hypothesis states that there is no difference between two treatment groups
    1. Type I:
             o     null hypothesis rejected despite being true
             o     detecting a difference when one does not really exist
    2. Type II:
             o     null hypothesis accepted when it is false
             o     Failure to detect a difference when one actually does exist




Power

        Ability of trial to detect an actual difference
        Equal to type II error




Significance level

        Statistical probability of a type I error




Confidence interval

        Probability of a true population mean lying within a range derived from a sample
         mean and it's standard error (standard error = standard deviation/number of
         observations)




Sensitivity / Specificity

    1. Sensitivity: ability to identify a true positive
    2. Specificity: ability to exclude a false negative




Averages / Measures of spread

        Mean, median, mode
        Standard deviation: - measure of scatter around the mean




Statistical test       Data types                          Uses

Student t-test         Paired means between two sampls Not for more than two means

Analysis of variance Multiple independent groups
Chi-squared




Clinical trial designs

      Randomised (minises bias)
      Case - control
      Cross over
      Double-blind (useful when trial has subjective endpoints)


Diathermy

Basis of diathermy

   1. Electrical current converted to thermal energy
   2. Amount of heat is proportional to volume of tissue traversed by current (need for
      broad contact with diathermy pad)

Types of diarthermy

   1. Monopolar
          o Circuit: plate, cable, patient
          o Cut (most effective when electrode placed a small distance away from
              tissue): continous current discharges across air gap, high temperature sparks
              generated, causes cellular water to explode
          o Coagulate: intermittent current released: tissue damage occurs by
              "fulguration", intermittent bursts of energy generated smaller effects
   2. Bipolar
          o Current transferred between two electrode (tips)
          o Safer but only able to coagulate

Key points

      Check position of pad (surgeon's legal responsibility)
      Avoid monopolar diathermy if patient has pacemaker; position plates away from
       pacemaker
      Avoid diathermy on long pedicles (ie, testis, penis, finger) as current with cause
       thrombosis of vessel
      Check insulation
      Avoid use in GI surgery - farting causes explosions


Drains

Indications
   1. Drain collections
   2. Prevention of collections before they accumulate

Pros:

   1. Drainage removes potential sources of infection
   2. May be early indicator of anastamotic leakage
   3. Leaves a tract for drainage (once removed)

Cons:

   1. May increase infections
   2. May induce leakage

Classification

   1. Active / passive
          o Active: Maintained under suction (high or low pressure)
          o Passive: No suction (relies on pressure differences between cavities)
   2. Open / closed
          o Open: Corrugated sheets drains into gauze or bag. May become infected
          o Closed: Tubed draining into bag. Less risk of infection
   3. Material
          o Minimal tissue reaction
          o Tissue reaction - eg in biliary surgery

Examples

Chest drains
Abdominal drains
Urinary catheters
VP Shunts / EVDs


Dressings

Optimum environment for wound healing

   1.   Moist
   2.   Free from infection, with minimal slough
   3.   Free of chemicals and foreign bodies
   4.   Optimum temperature
   5.   Minimal number of dressing changes
   6.   Correct pH

Different dressings are appropriate for different stages of the wound healing

Good wound management necessitates flexible approach to election and use of
dressings
Requirements from a dressing

   1. Wound
             o   Protection from infection and trauma
             o   Debrides, both mechanically and chemically
             o   Absorbent and removes excess exudate, whilst keeping wound moist
             o   Maintains temperature and gaseous exchange
   2. Patient
             o
             Comfortable and cosmetically acceptable
             o
             Stimulates healing
   3. Healthcare provider
         o Inexpensive
         o Easy to change

                                                      Brand
Type                Description                                    Indications
                                                      names

                    Available as pastes, granules,
                    wafers
                    Mixture of
Hydrocolloids       carboxymehtylcellulose, pectins, Granuflex     Wet sloughly wounds
                    gelatins, elastomers
                    Forms gel on contact with wound
                    secretions, absorbing secretions

                    Consists of
                    carboxymethylcellulose spun into
                    fibre                                          Heavily exudating
Hydrofibre                                           Aquacel
                    Forms gel on contact with wound                wounds
                    secretions, which absorbs
                    secretions

                    Insoluble polymers, water and
                    propylene glycol
Hydrogels           Absorbs large volumes of                       Desloughing/debriding
                    exudates and effective at
                    desloughly/debriding

Semipermeable       Clear polyurethane film coated                 Not suitable if excessive
film dressings      adhesive                                       exudate

                    Derived from seaweed
                                                      Kaltostat,
Alignates           Absorbs secretions to form gel to
                                                      sorbsan
                    optimise moist wound healing
                    Consists of polyurethane /
Foam dressings      silicone foam                                  Flat / cavity wounds
                    Very absorbant

Antimicrobial
                    Little evidence for benefit
dressings

                      Can facilitate cell proliferation,
                      production of extracellular matrix
                      Epidermal components -
Artificial and living
                      Vivoderm
skin equivalents
                      Dermal components - Dermagram
                      Composite grafts (epidermal /
                      dermal components)



Fracture healing

Stages of fracture healing (HIDOCR)

    1. Haematoma formation
            o size limited by elastic periosteum and arterial spasm
    2. Inflammatory phase
            o vascular dilation, exudate, polymorph infiltration
    3. Demolition phase
            o Macrophages digest clot, fibrin and debris
            o Macrophages & osteoclasts remove dead bone fragments
    4. Organisation
            o Granulation tissue formation with ingrowth of capillary loops from below
                the periosteum and from fracture bone ends
    5. Early callus/late callus
            o Osteoid laid down in haphazard arrangement of fibril
            o Mineralise to form woven bone +/- cartilage
            o Woven bone absorbed by osteoclasts and osteoblasts which lay down
                lamellar bone (with haversian blood systems)
    6. Remodelling
            o Normal shape of bone is remodelled over many months and marrow cavity
                reforms

Abnormalities of fracture healing

       Non-union: when foreign material interposed
       Delayed-union: (1) sepsis (2) movement (3) FB (4) ischaemia (5) poor nutrition
       Malunion
       Fibrous union: occurs when there is excessive movement. Cells can differentiate into
        synovial cells and results in a pseudoarthrosis
Gunshot wounds / Blast Injury

Classification of Blast Injury

   1. Primary: from the shockwave itself
   2. Secondary: from flying debris
   3. Tertiary: from the body being thrown (becoming a projectile itself)


Informed Consent

The law recognises that it is in the best interest for emergency treatment to go ahead if
it is necessary to save a life or to prevent serious or permanent disability.



Consent

       Process where patients understand and agree to treatment
       Full discussion of disease, treatment, benefits, risks and alternative treatments
       Verbal or written
       Patients can change their mind / seek alternative opinions
       Children: (1) Child able to consent if judged to be competent (2) otherwise parent or
        legal guardian can act on behalf (3) Child cannot refuse treatment
       Adult: (1) Only the adult or (2) someone with power of attorney. Relatives should be
        involved but cannot consent or withold consent on another individual's behalf.

Who should obtain consent?

       Operating surgeon
       Suitably qualified person who has knowledge of procedure and understanding of
        risks and benefits.
       All complications with >1% risk should be discussed
       Potentially life-threatening risks should be discussed


Intensive Care (ITU)

Levels of care

   1.   Level 0: Ward patient
   2.   Level 1: Ward patient needing critical care team input
   3.   Level 2: HDU care: single failing organ
   4.   Level 3: ITU care: multiple failing organs - 3-4 times more expensive than routine
        ward care

Admission criteria

   1. Disease treatable / reversible
   2. Two or more organs affected
   3. Does not breach wishes of patient

Transfer of Critically Ill

   1. Primary transfer
          o From scene of trauma to hospital
          o Managed and organised by pre-hospital team
   2. Secondary transfer
          o Transfer between hospital (eg to neurosurgical units)




Necessary equipment

   1. Support
           o Oxygen
           o Ventilator
           o Suction
   2. Monitoring
         o ECG
         o Sats
   3. Emergency treatment
         o Fluids
         o Defibrillator
         o Drugs -

Modes of transportation

   1. Ground - Ambulance
   2. Air - Helicopters / planes (RFDS)
           o Risk of hypoxia (due to altitude)
           o Gaseous exansion leads to tension pneumothorax - prophylactic bilateral
               chest drains
   3. Sea


Nerve Injury

Classification of nerve injury

               Pathology                      Recovery              Example

            Physiological defect associated
                                                                    Nerve compression
Neuropraxia with ischaemia or focal           6-12 week recovery
                                                                    injury
            demyelination

               Axonal distruption with        Regeneration starts   Traction injury to
Axonotmesis                                   after 1 month         limb
               endo/peri neurium intact
                                              Growth of 1mm/day     Stretched nerve in
                                                    Prognosis worse with    dislocated limb
                                                    more proximal lesions

                                                    Poor prognosis without
                                                    repair
                                                    (Needs diagnosis with Accidentally cut
Neurotmesis Axonal transection
                                                    serial EMGs)           nerve
                                                    Exploration and repair
                                                    are indicated



Operating list order

Patients who should be first on the list

   1.   Diabetics
   2.   Major operations*
   3.   Poor anaesthetic candidates
   4.   Significant allergies

Patients who should be last on the list

   1.   High risk infection - HIV, hepatitis, CMV
   2.   Septic
   3.   MRSA
   4.   Contaminated / dirty wound


Paediatrics




Airways

       Tongue large
       Epiglottis relatively larger
       Larynx higher up (C3/4)


Palliative care

Palliative care

       Deals with dying
       Aspects dealt with: social, psychological, medical

Principles

   1. Die with dignity
          o Patient should be moved to a quiet side room
          o Family may wish to be present
          o Religious wishes respected
   2. Die without suffering
          o Investigations / blood tests should be cancelled
          o Potentially degrading objects (such as nasogastric tubes) should be removed
   3. Die with control of symptoms
          o Anti-emetics
          o Reduced secretions: hyoscine
          o Treat constipation



Patient safety in theatre

Surgeon's duty

   1.   Check correct patient, operation, side, consent
   2.   Suitably starved
   3.   Appropriate antibiotics
   4.   Adequate intra-operative DVT prophylaxis
   5.   Safe transfer to operating table
   6.   Correct positioning


Radiotherapy

Radiotherapy

   1. Therapeutic use of radiation in the management of cancer
          o Electromagnetic: photons, x-rays, gamma rays
          o Particulate: electrons, neutrons
   2. Ionizing radiation = amount of energy absorbed per unit mass of tissue (measured in
      grays)
   3. Delivery: linear accelerator
   4. Mechanism of cellular damage
          o Damage of DNA - free radical formation leads to chromosomal damage and
               cellular death
          o Can also induce cellular apoptosis
          o Amount of damage is proportional to the dose of radiation

Planning treatment

Factors to consider

   1. Radiosensitivity of tumour?
         o Highly sensitive: lymphoma, myeloma, seminoma
            o Moderately sensitive: breast, ovarian, teratoma, BCC, Small cell lung
              carcinoma
          o Moderately resistant: cervical carcinoma, bladder carcinoma, rectal
              carcionma, sarcomas
          o Highly resistant: melanoma, osteosarcoma, carcinoma of pancreas
   2. Extent of tumour
   3. Tolerance of normal tissues to radiation
          o Damage minimized by 3d imaging to ensure maximum radiation dose is
              delivered to tumour itself
          o Moulds created (as in head/neck cancers), tattoos of chest wall in breast
              cancer (ensure same position each time)
          o "Wedge" fields - multiple fields necessary
          o + "Shrinking" method to allow margins of treatment to be reduced during
              last few weeks of treatment

Complications

   1. Acute
            o   Fatigue
            o   Anorexia, nausea
            o   Skin irradatioatn- erythema/desquamation
            o   Mucosal irradiation - diarrhoea
            o   Dysphagia
            o   Temporary alopecia
            o   Sterility
   2. Late
            o   Telangectasia
            o   Loss of saliva production
            o   Pulmonary damage
            o   Bowel strictures


Screening

Screening

Programme to detect unsuspected disease in a population of apparently healthy people

Surveillance

Programme to detect disease in a population already with disease



Important considerations

   1. Disease
            o   Common
            o   Important
            o   Long premobid latent period
            o   Detectable at early stage
           o   Treatable: by defined principles, cost-effective
   2. Test
           o   Sensitive (ability to detect)
           o   Specific (ability to exclude others)
           o   Non-invasive
           o   Acceptable to patients
           o   Cost-effective
           o   Does no significant harm to patients

Examples

   1. Breast cancer
          o All women over 50-64 advised to have mammogram every 3 years.
          o Mammographic abnormalities referred to breast specialist for clinical
              examination + further investigations
          o 5-10% breast cancer familial
          o Genetics: BrCA1 (chromosome 17), BrCA(chromosome 13),
              p53(chromosome 17), Ataxia telangectasia gene
          o Detected cancers: smaller, CIS, well differentiated (ie. all rather good
              prognostic factors)
   2. Ovarian cancer
          o Two or more 1st degree relatives
          o BrCA1,BrCA2 genes
   3. Cervical cancer
          o 3 yearly Papanicolau smears
          o CIN 1,2,3
          o Treated with cone excision biopsy
   4. Colorectal cancer: at risk families, polyps, IBD
          o Faecal occult blood-testing kit, plus repeat test
          o If positive > colonoscopy or double contrast barium enema
   5. Abdominal aortic aneurysms
   6. Congenital dislocation of hip
          o Ortolani
          o Barlow's
   7. Prenatal screening

Bias in screening

   1. Lead-time bias: Survival measured from detection to death will be longer (cause it's
      detected earlier)
   2. Selection bias: Individuals who take up screening are more health conscious
   3. Length bias: slowly growing tumours more likely to be detected by screening than
      rapidly growing tumours between screening intervals

Problems in screening

      Increased morbidity with unaffected prognosis
      Excessive therapy of doubtful cases
      Increased anxiety
      Lack of target population co-operation
      Costs
       Inffective screening tests
       False reassurance


Sterilisation & disinfection

Sterilisation

       Process which kills all living microorganisms (including viruses, spores - clostridium,
        bacillus: rests heat, dehydration, chemical attack, ionising radiation)

Disinfection

       Process which kills most living microorganisms (except spores and viruses)




Sterilisation methods

Method                                 Temperatures Type of equipment

Moist heat (autoclave) - steam under 134/3min                  Dressings
pressure                             121/15min                 Instruments

                                                               Moisture sensitive
Dry heat (hot air)                     160/2hours
                                                                equipment

                                                               Plastics
Ethylene oxide
                                                               Sophisticated equipment

Gamma radiation                                                Plastics and prostheses




Disinfection Methods

       Skin preparation
       Glutaraldehyde treatment of endoscopes




Determining adequacy of sterilisation
                                                                                Tubes
                                                                                contain
Browne'
                                                                                heat
s tubes
                                                                                sensitive
                                                                                dyes




                                                                                Stripes
                                                                                change
Bowie                                                                           to dark
Dick                                                                            colour
tape                                                                            once
                                                                                sterilise
                                                                                d



Lantor
test




Precautions to avoid infection

   1. Theatre suites
          o Theatres sited away from main hospital traffic
          o Clearly designated areas of asepsis etc
          o Positive-pressure (plenum) ventilation with 20 air changes/hour / Ultra-
              clean laminar airflow systems with 300 air changes/hour
   2. Theatre staff
          o Minimum number of individuals necessary in theatre
          o Avoidance of excess traffic through clean areas
   3. Operating personel
          o Gowns - cotton gowns reduce bacterial count by 30%
          o Caps / masks
          o Scrubbing
   4. Patient
          o Minimal pre-operative stay
          o Pre-operative showering
          o Shaving only if required immediately prior to surgery
          o Skin preparation - 1% iodine or 0.5% chlorhexidine in 70% alcholol
Universal precautions

Precautions taken to protect theatre staff from infections in all patients

   1.   Gowns
   2.   Gloves
   3.   Masks/visors/goggles
   4.   No-touch technique when handling needles
   5.   Safe disposal of sharps


Stoma

Stoma

       Artificial opening allowing connection between two surfaces

Uses

   1. Input
           o   PEG / gastrostomy / jejunostomy - allow feeding
           o   Tracheostomy - allow air
   2. Output
           o  Ileostomy
           o  Colostomy
   3. Diversion
          o Nephostomy / urostomy - divert flow of wee
   4. Decompression
          o Tube thoracostomy
          o Laparostomy




Complications of GI Stoma

   1. Local
           o  Skin irritation
           o  Leakage
           o  Odour
           o  Prolaps
   2. Systemic
          o Electrolyte imbalances
          o Malabsorption
          o Short gut syndrome
   3. "Surgical"
          o Strangulation / ischaemia
          o Inadequate diversion and spillage
          o Stomal stenosis
          o Retraction
              o   Stomal ulceration




Formation of End Ileostomy

Indications

       Permanent stoma after total colectomy

Terminal ileum has absorptive functions - try to preseve as much as possible

   1.   GA + NGT + Antibiotics + DVT
   2.   Incise 2cm circle of skin over appropriate area (LIF)
   3.   Dissect down to rectus and make cruciate incision
   4.   Deliver ileum
   5.   Stitch ileal serpsa and mesentry to anterior abdominal wall
   6.   6-8 cm protrusion to form spout (ideal spout should be 2-3cm)




Formation of Loop ileostomy




Formation of Loop colostomy

Indications

       Defunction distal obstructed colon

   1. GA + NGT + DVT + Catheter + supine position
   2. Formation of stoma
          o Pick up skin, incise 2cm down to rectus sheath
          o Cruciate incision
          o Dissect down to peritoneum, avoid inferior epigastric artery
          o "Rubber sling" the colon with a cather, and draw out into wound
   3. Fixation of stoma
          o Place colostomy bridge
   4. Open bowel longitudinally along taeniae with knife (allow explosive gases to be
      release
   5. Suture edges of stoma to skin using interrupted sutures
   6. Clean skin + apply colostomy appliance

Closure of Loop colostomy
Indications

       Restore bowel continuity after temporary diversion
       When stoma has "matured" (at least 2-3 months)
       Recovered from primary pathological process necessitating stoma

   1. NGT + GA + Antibiotics + DVT + catheter
   2. Release stoma / free bowel
          o Incise around stoma about 0.5cm from the mucocutaneous edge
          o Apply traction upwards
          o Deepen incision and angle towards colon
   3. Close defect
          o Excise old stoma
          o Close colon with interrupted 2/0 full thickness sutures
   4. Close wound in layers


Surgical Audit

Audit

       Quality control process
       Critical and systematic review of practice against set standard
       Aim to improve quality of surgical care

Audit subtypes

   1. Structure: - organisation, resources
   2. Process: - way in which patient has been managed from admission to discharge
   3. Outcome: - outcome of surgical intervention

Stages in Audit process

   1.   Define audit topic
   2.   Collect data + verification by peer review
   3.   Data analysis
   4.   Presentation of results + recommendations
   5.   Re-audit

Requires honesty, completeness, objectivity



Examples

   1. NCEPOD (National Confidential Enquiry into Peri-operative Deaths
         o Improve standards of surgical practice
   2. ICNARC (Intensive Care National Audit And Research Centre)
   3. MINAP (Myocardial Infarction National Audit Project)
Sutures / Needles

Characteristics of an ideal suture

Surgeon                      Patient                       Healthcare provider

Easy to handle               Minimal tissue reaction       Inexpensive
Secure                       Minimal trauma                Easy to produce
Predictable tensile strenght
Predictable absorption
Sterile




Classification of sutures

Absorption                      Construction                    Composition

Absorbable: vicryl, PDS, catgut Monofilament: Nylon,            Natural: Silk, catgut, steel
Non-absorbable: nylon, silk, prolene, PDS                       Synthetic: Nylon, PDS
prolene, steel                  Multifilament: braided
                                (vicryl), twisted (silk)




Classification of needles

Shape                           Point                           Body

Straight (subcuticular)         Cutting                         Cutting
Curved                          Tapered                         Reverse cuttinh (reduces
Special: J-shaped,              Blunt (bowel surgery)           tissue cut out)
compound curve                                                  Round bodied (bowel
                                                                anastamosis)



Abdominal pain differentials

Ureteric Colic

    1. Renal:
             o   kidney stones
             o   Tumour (clot colic)
             o   Pyelonephritis
             o   Renal infarction
           o  Stricture
           o  Papillary necrosis
   2. Vascular
         o AAA
         o Bowel infarction
   3. Gastrointestinal
         o Acute appendicitis
         o Diverticulitis
   4. Gynae
         o Ectopic pregnancy
         o Salpingitis
         o Torsion ovarian cyst



Theatre design

Theatre design

   1. Location
          o Close to surgical wards / ITU / Supplies / A&E / Imaging
   2. Layout
          o Separate clean / dirty areas
          o Anaesthetic room adjacent to theatre
          o Adequate space for storage
          o Staff recreation
   3. Enviroment
          o Ideal temperature 20-22'C
          o Humidity control (hog-hair hygrometer)
          o Clear filtered air - enters via ceiling, leaves via door flaps
          o Power
          o Gas
          o Lighting



Tourniquet

Indications

      Ensure accurate bloodless field
      Prevent systemic toxicity in isolated limb perfusion with cytotoxic drugs
      biers block (guanethidine block)




Contraindications

      Peripheral vascular disease
      Elderly (relative)
      Patients at risk of DVT when operating on lower limbs
Procedure

   1.   Give agent / iv first - can take up to 5 minutes for systemic circulation
   2.   Elevate limb, exsangiunate (with "exsanguinator" / esmarch bandage)
   3.   Apply soft padding
   4.   Apply tourniquet; inflate to >70-100mmHg systolic
   5.   Note tourniquet time
   6.   Warm anaesthestist prior to tourniquet release

Lower limb 90-120 minutes
Upper limb



Complications

   1. Tourniquet site
          o Skin: friction burns / chemical burns if applied to skin
          o Nerve: Compression leads to neuropraxia
   2. Distal to tourniquet
          o Vascular: Ishaemia / thrombosis
          o Muscular: reperfusion injury (1) free radials released into hypoxic tissues (2)
   3. Systemic
          o Haemodynamic changes at time to inflation/deflation
          o Tissue hypoxia / cell lysis - raised lactate/acidosis, hyperkalaemia
          o Hypercoagulability
          o PE



Transplantation

Types of Grafts

Homograft = self
Heterograft = same species
Xenograft = different species



Transplant considerations

   1. HLA matching:
         o Histocompatibility antigens defined by tissue typing - A, B, C, DP, DQ, DR
             (chromosome 6)
         o HLA Match essential: renal, pancreas
         o HLA Match non-essential: cardiac, hepatic
         o ABO blood group essential: renal, pancreatic, cardiac, hepatic (ie, all of
             them)
   2. Donor considerations
         o Established brainstem death
         o No sepsis
           o   No maligancy (except primary brain)
           o   No HIV, HBV
           o   Not high risk : IVDU

Graft rejection

   1. Hyperacute rejection
         o recipient serum antibodies vs donor antigens (very bad news) - thrombosis,
              graft infarction within hours
         o treat by removal of graft
   2. Acute rejection
         o cell-mediated CD4 immunocytes (T-helper) within 3 months
         o Treated with steroids / immunosuppression
   3. Chronic rejection
         o Humoral / cell-mediated immune responses occurs months - years
         o Not treatable or reversible



Wound healing

Wound healing

   1. First intention:
           o clean surgical wounds withouth tissue loss that heals with minimal fibrosis
   2. Second intention:
           o wounds left open that heal to fill gap with extensive fibrosis (granulation
               tissue, contraction, epithelisation)
           o Used when no possilibity of tension-free approximation (loss tissue,
               oedema, infection)
   3. Third intention:
           o delayed primary closure (wounds with high risk of infection if closed early;
               dog bites, contaminated wounds, delayed presentation)
           o best left for exploration, debridement and toilet with antibiotics and closure
               after 3-10 days




Stages in wound healing

   1. Events at epidermis
         o Clot formation at site
         o Epithelial cells migrate from wound edges (under the clot)
         o Integrins on keratinocytes bind to fibronectin
         o Proliferation of keratinocytes contributes to the ability to cover wound
   2. Events at dermis
         o Infiltration of polymorphs, macrophages to remove debris
         o Fibroblast activity to restore tensile strenght
         o Revascularisation
         o Myofibroblast contraction
Growth factors involved

      Platelet derived growth factor
      Epidermal growth factor
      Transforming growth factor
      Cytokines
      Tumour necrosis factor




Granulation tissue

      Vascular: proliferating capillary buds
      Fibrous: fibroblasts
      Inflammatory cells: Macrophages

Takes part in healing process
Potentially deleterious in joint destruction (rheumatoid arthritis by granulation tissue -
Pannus)
Tissue is resistant to infection. Not resistant to trauma, chemical agents, radiation



Factors affecting wound healing

   1. Patient
           o    Old
           o    Obese
           o    Smoking
           o    Systemic diseases- diabetes, cardiac disease, immunosuppression, poor
                nutrition
   2. Wound
           o    Hypoxia / ischaemia
           o    Infection / contamination
           o    Mobility across wound
   3. Surgery
           o    Inadequate debridement
           o    Excess tension
           o    Suture necrosis




Dehiscence
Failure of wound to heal in apposition
Partial / total disruption of surgical wound



Signs of Impending wound dehiscence

      Low grade pyrexia
   "Pink fluid" sign
   Abdominal distension
   Abdominal pain

				
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