Principles of Surgery

Principles of Surgery

METABOLIC RESPONSE TO SURGERY

• ↑ sympathetic activity, circulating cathecolamines & insulin
• Cytokine responses signal other cells to prepare for starvation, provide additional energy and building block for tissue repair, and conserve Na and water.
• catecholamines and glucagon stimulate lipolysis in adipose tissue releasing fatty acidsà provide energy source for peripheral tissues
• Breakdown of muscle protein release amino acids, the main substrate for gluconeogenesis.
• enhanced hepatic glycogenolysis and gluconeogenesis – aided by increased adrenaline and noradrenaline from sympathetic nerve ending and adrenal medulla
• ↑ ACTH, glicocorticoids (cortisol), glucagon and growth hormone à catabolic response
• ↑ aldosterone and ADH mediate some of the fluid and electrolyte changes
• Insulin acts as an antagonist of most of the above hormones and is increased from second or third day after injury

3 Phases

Ebb phase

• Glycogenlysis and lipolysis
• Provides body with energy
• Anabolic phase
• Various length – depends on  surgery/injury

Flow phase

• Catabolic phase
• ↑metabolic rate, ↑ temp and pulse,  increased urinary nitrogen excretion  (loss of muscle),

Convalescence phase

• Can last weeks to months
• Depends on numerous factors:
  • Patient factors
  • Type of surgery
  • Complications

SHOCK

a sudden and generalised lack of perfusion to the vital tissues.

Types

Cardiogenic – pump failure

Hypovolaemic -↓circulating blood volume (CBV = 70ml/kg in adult, 80 in infant)

• True – loss of blood(haemorrhage), plasma(burns), dehydration
• Apparent - ↑ vascular capacity – sepsis, adrenal insufficiency, anaphylaxis

Anaphylactic- hypersensitvity reaction to an allergen

Neurogenic – post spinal surgery

Septic – action of bacterial endotoxin and xytotoxin on CVS

Clinical features

	Hypovolaemic	Cardiogenic	Septic	Anaphylactic
Skin colour	Pale	Pale	Flushed	Urticarial rash
Sweating	Present	Present	Absent	Absent
temperature	Cold	Cold	Warm	Warm
Capillary refill	slow	slow	rapid	normal/rapid
Central venus pressure	Low	High	Low	Low
Mental status	Restless	Quiet	Drowsy	Variable

Management

Pulse rate, BP, RR, Temperature

If BP unrecordable, call cardiac arrest team

ABC – including high flow O2

Raised foot of the bed

IV access x 2 (wide bore, get help if this takes >20 min)

Identify and treat underlying causes

• Cardiogenic- manage in CCU, diamorphine (pain & anxiety), thrombolytic therapy and aspirin.
• Hypovolaemic – fluid repacement (saline or colloid), if bleeding, use blood), titrate against BP, CVP, urine output
• Septic – IV cefuroxime or gentamycin + antipseudomonal penicilin(ticarcilin)
• Anaphylactic shock- - IV fluid, adrenaline IM, antihistamine
• Heat exposure- tepid sponging, + fanning: avoid ice and immersion. Resusciate with high sodium IVI.

Infuse crystalloid fast to raise BP (unless cardiogenic)

ECG – identify PE (20% have S-wave in lead 1 and Q waves and inverted T waves in lead III: S1QT3)

Venous blood sample- Hb, haematocrit, urea, electrolyte, cardiac enzymes

Grouping and crossmatch if haemorrhage

Bacterial blood culture if sepsis

Urine output hourly (catheter)

Central venous Pressure

Blood Gas Analysis and arterial pH

Hypovoleamic Shock

Grades

Class	1	2	3	4
Blood loss	0-750ml	750-1500ml	1500-2000ml	>2000ml
% blood loss	15%	30%	40%	>40%
Pulse	<100	>100	>120	>140
BP	normal	normal	decreased	decreased
PP	normal	decreased	decreased	decreased
Urine output	>30ml/hr	20-30ml/hr	5-15ml/hr	Anuria
Resp rate	14-20	20-30	30-40	>40

Complications

• Disseminated intravascular coagulation – dx:high serum fibrin degredation products, Tx: fresh frozen plasma and platelets
• Stress Ulceration- gastric erosion due to mucosal ischemia, back diffusion of H+ → acid secretion. Tx: antacids, sucralfate
• Acute respiratory failure – sepsis, fat embolism, massive blood transfusion, oxygen toxicity and DIC.Tx: supportive, intermittent positive pressure ventilation, GI or IV feeding
• Acute renal failure – fall in GFR. Tx: IVI restricted to 400mL/day, IV glucose and insulin, peritoneal dialysis/haemodialysis
• Acute hepetic failure

FLUID THERAPY

Daily requirements:

For the ‘average’ 70 Kg man

• Total body water is 42 L (~60% of body weight)
• 24L is in the intracellular and 14 L in the extracellular compartments
• The plasma volume is 3 L
• The extravascular volume is 11 L
• Na: 2mmol/kg
• K: 1 mmol/kg

    * Clinical history and observations – Pulse, blood pressure, skin turgor

    * Urine output – oliguria < 0.5 ml/kg/hr

    * CVP or pulmonary capillary wedge pressure

    * Response of urine output or CVP to fluid challenge

    * A fluid challenge should be regarded as a 200-250 ml bolus of colloid

    * This should be administered as quickly as possible

    * A response in the CVP or urine output should be seen within minutes

    * The size and duration of the CVP response rather the actual values recorded is more important

Indication

• Preoperative resusciation
• replacement of abnormal losses: vomiting, diarrhoea, ileostomy bag
• NBM
• Postoperative resuscation
• Electrolyte disorder
• abnormal losses – NG aspirate (rich in Na, K), vomit, diarrhoea, stoma, drains, fistula

Maintenance requirements

Adults require approx 30-40mls/kg/day

Children require considerably more

• 0-10 kg -100 ml/kg
• 10-20 kg -1000 ml + 50 ml/kg for each kg > 10
• >20 kg -1500 ml + 25 ml/kg for each kg > 20 

Assessing Fluid balance

• Vital signs-pulse,BP
• Urine output
• Dry mucosal surfaces
• Skin turgor
• Mental status
• Capillary return

Types of fluid

1.  Crystalloids

• Normal saline – 1L contains 154 mmol NaCl
• Dextrose saline – 1L contains 31mmol NaCl + 40g dextrose
• 5% Dextrose- 1 L contains 50g (278mmol) dextrose
• Hartmann's solution – 1L contains 2 mmol Ca, 4 mmol K, 28mmol HCO3, 130 mmol Na 109 mmol Cl
• Solution 18 – 1L contains 31 mmol NaCl

2.  Colloids

Natural : blood, albumin

Synthetic: gelatin-based infusion – 1L contains 35g gelatin, 6.25 mmol Ca, 145mmol Cl, 145 Na

Typical daily fluid replacement:

• 1L 0.9% NaCl + 20 mmol K over 8H plus
• 2L 5% dextrose + 40mmol K each litre over 8h
• 3L dextrose saline + 60mmol K over 8h

NUTRITION

Essential for

• Wound healing
• Immunological shield
• Maintaining normal functioning of organs

The Fasting State

After 12 hours of fasting the nutrients provided have been utilised.

• Plasma insulin levels fall
• Glucagon levels rise

Glycogen is stored in the liver, muscle

The liver converts glycogen into glucose

Muscle glycogen is broken down into lactate, exported to the liver and converted into glucose

After 24 hours glycogen stores are  depleted and gluconeogenesis  occurs  mostly in the liver

Protein is broken into amino acids  which undergo gng to form glucose

Fat is broken down into

• Glycerol-glucose
• Fatty acids-ketone bodies in the liver

Requirements in the healthy person

CHO and lipids are the  mainstay of energy intake

20-25kcal/kg/day

Vitamins

• metabolic co-enzymes
• co-factors in wound healing
• antioxidants

Trace elements

• Eg zinc, copper, iron
• cofactors for metabolic processes
• components of body tissues

Nitrogen-approx 12g/day-  normally provided by protein

Changes in calorific  needs

Postoperatively-35kcal/kg/day

Increases 10% per degree  increase in temperature

Sepsis- 40-45kcal/kg/day

Hypercatabolic states (burns,  severe pancreatitis)-60kcal/kg

Assessing nutritional  status

Assessing Nutritional Status

Body Weight and  anthropometric  techniques

Body weight (loss of 10% of BW in preceding 6 months is an indicator of poor clinical outcome)

Triceps skin fold thickness(body fat mass)

Mid-arm muscle circumference(muscle mass)

Body mass index

• BW in kg
•    Height in m2
• Note these values can be inaccurate in the presence of oedema which occurs when there are changes in fluid balance in critically ill patients with fluid retention

Clinical assessment

Clinical history- weight change, dietary intake

Physical examination- muscle wasting, loss of subcutaneous fat, oedema, alopecia

Hand grip strength and respiratory function assess functional impairment which is associated with undernourishment.

Laboratory techniques

Serum albumin can be an  indicator of nutritional status

However it is affected in the  acute phase response and by  inflammation

  (where it falls rapidly and  therefore is of little use in  assessing nutrition)

U&E-Ca, Mg, PO4, Na, K

Feeding options

• Oral
• Enteral
• Parentral

Enteral Nutrition

Parenteral Feed

Requires GIT to be intact Suplimental energy drinks Nasogastric(NG)/jejunal feed (NJ) PEG/PEJ, Jejunostomy feed Feed varied for purpose Elemental feed Indications Dysphagia (esp for solid food) Major trauma/Surgery- when fasting will be prolonged IBD(Short gut syndrome,Crohn’s,Pancreatitis) Distal low output enterocutaneous fistulae Oesophagogastric surgery. Monitoring of patients on enteral  feeding Clinical assessment Daily weights Fluid balance Twice weekly electrolytes and trace  elements Metabolic complications Electrolyte abnormalities, hyperglycaemia tube malpositioning Clogging Aspiration peritonitis aspiration feed intolerance enteric infection High gastric residuals Diarrhoea

Delivery intravenously through central venous catheter or PICC Peripheral parenteral nutrition Total parenteral nutrition TPN constituants               Water               Protien (amino-acids) 10%               Cardohydrate (dextrose) 70%               Fats (lipid emulsion) 20%               +/- Electrolytes               Vitamins               Medications Indications Proximal intestinal fistulae Massive intestinal resecton especially  <100cm of bowel left. Severe pancreatitis Prolonged ileus Contents of TPN >50% CHO 40% fat emulsions 1-2g/kg of fat/day H2O 35ml/kg/day Electrolytes-Na, K, Cl, Ca, Mg, PO4 Nitrogen Vitamins ADEK B&C Monitoring patients on TPN Weight U&Es, FBC, LFTs Glucose Temperature and Vitals(signs of sepsis) Daily inspection of line Trace elements TPN complications Complications of central venous access Metabolic complictions Hyperglycaemia Sepsis Pneumo/haemothorax Arterial damage/thrombosis Malposition of catheter Cardiac arrythmias Electrolite abnormalities Refeeding syndrome GUT atrophy Small bowel bacterial overgrowth Choleostasis & hepatic dysfunction Acalculous cholecystitis Metabolic derangement TPN jaundice Hyper/Hypoglycaemia Electrolyte disturbances Vitamin/Trace element deficiency

Lines

Peripheral	Central (single/multiple lumen)
Intravenous canulae	PICC lines Untunnelled Tunnelled Subcutaneous ports
Complications               Thrombophlebitis               Infection               Sclerosis of vein               Extravasation	Pneumothorax               Bleeding/haematoma               Arterial puncture               Catheter tip malposition               Air embolism               Catheter dysfunction               Extravasation               Thrombosis               Infection

ANAESTHETIC REVIEW

Suitability for surgery

• Cardiac
• Respiratory

Need for blood products

Type of anaesthetic GA versus  spinal

Post op analgesia required

Assessment of cardiac  function

non-invasive	CXR	indicated in the presence of cardiorespiratory symptoms or signs Increased cardiac morbidity associated with Cardiomegaly Pulmonary oedema
	ECG	features of ischaemia or previous infarction(LBBB) may be present Stress test- if there are symptoms of IHD such as chest pain, SOB on exertion 24-hour monitoring is useful in the detection and assessment of arrhythmias Assessment of cardiac  function
	Echo	Percutaneous Transoesophageal(TOE) Allows assessment of Muscle mass Ventricular function / ejection fraction End-diastolic and end-systolic volumes Valvular function Segmental defects
	Exercise test
invasive	Coronary angiography
	Thallium scanning	Nuclear medicine Myocardial scintigraphy allows assessment of myocardial perfusion Radiolabelled thallium is commonest isotope used Areas of ischaemia or infarction appear as 'cold' spots

Assessing respiratory  function

Lung function tests

• predict the type and severity of lung disease
• predict risk of complications and postoperative mortality

Lung Volumes	Airway calibre	Gas transfer
Assessed with spirometry   Volumes measured include: IC IRV  TV VC FRC RV ERV TLC	Assessed by Peak flow rates Flow rates measured FVC = Forced vital capacity FEV1 = Forced expiratory volume in one second Absolute values depend on height, weight, age, sex and race FEV1 / FVC ratio is important# Lung function can be classified as: Normal Restrictive Obstructive Restrictive lung disease FVC is reduced but FEV1/FVC is normal Obstructive lung disease FVC is normal or reduced and FEV1/FVC is reduced	Measured by arterial blood gases (ABG) Also allow assessment of ventilation / perfusion mismatch Important parameters to measure are pH Partial pressure of oxygen Partial pressure of carbon dioxide Pulse oximetry gives an indirect estimate of gas transfer Technique is unreliable in the presence of other medical problems (e.g. anaemia)

Assessment of Renal  function

Glomerular filtration rate is the gold standard test of renal function

• Can be calculated by measuring creatinine clearance rate
• Requires 24-hour urine collection

Serum creatinine allows a good estimate of renal function

may be inaccurate in patients with:

• Obesity
• Oedema
• Pregnancy
• Ascites

Anaesthetic preview

Medical co-morbidity increases  the risks already associated  with anaesthesia and surgery.

American Society of  Anesthesiologists devised a  grading system to accurately  predict morbidity and mortality

ASA grading

ASA Grade	Definition	Mortality
1	Healthy individual	0.05
2	Mild systemic disease that does not limit activity	0.4
3	Severe systemic disease that limits activity but isn't incapacitating	4.5
4	Incapacitating disease which is always threatening	25
5	Moribound	50

Cardiovascular disease-  Angina, Hypertension,  Diabetes. Grade 2-3

Respiratory disease- COPD,  Asthma. Grade 2-3

Planning postoperative  pain management.

Postoperative pain  management is essential for a  number of reasons

• Improved mobility
• Patient comfort
• Enhanced breathing
• Prevention of gut immobility

Analgesic Ladder

Paracetamol

• inhibits COX3
• useful for simple operations

NSAIDS

• used for moderate pain 
• as an adjuvant with opiates in severe pain
• nonspecific COX inhibition leads to its side effects especially loss of platelet function renal haemostasis and gastric cytoprotection

Codeine phosphate

• does not have a significant  respiratory effect
• useful in intracranial surgery

Stronger analgesics

• IM morphine
• PCA
  • IV or via epidural catheter
  • Patient controlled lock out time predetermined

Local analgesics

• continuous epidural anaesthesia with opiates or local anaesthetics

Spinal opiates

PREOPERATIVE BLOOO TESTING

• FBC
• U&E
• Coag screen
• Group and Hold

Coagulation tests

Prothrombin time (PT)

extrinsic and common pathways

measures factors II, V, VII, X and fibrinogen

PT is expressed as International Normalised Ratio (INR)

Prolonged in:

• Warfarin treatment
• Liver disease
• Vitamin K deficiency
• Disseminated intravascular coagulation

Activated partial thromboplastin time (APPT)

    Tests intrinsic pathways

Prolonged in:

• Heparin treatment
• Haemophilia and factor deficiencies
• Liver disease
• Disseminated intravascular coagulation
• Massive transfusion
• Lupus anticoagulant

PREOPERATIVE ASSESSMENT

Co-Morbitities

Diabetes

Optimise glycaemic  control : well controlled  sugars, normal HbA1c

• Decreased chance of  hypo/hyper intra-op
• Quicker recovery
• Better wound healing

Endocrine R/V

First on theatre list

Minor Surgery: NIDDM	Minor Surgery: IDDM	Major surgery
Pre-op: random BS Omit OHA morning of  surgery Monitor BS q 1hr intra-op Restart OHA with first meal	Pre-op: normal meds Day of op: no breakfast, no  insulin Check BG every hour Restart insulin with first  meal	First on list No insulin or OHA morning of surgery Intra-op: IV infusion 5% dextrose KCL Insulin Change consituents according to BS

Post-op:

• NIDDM: restart OHA with  first meal
• IDDM: stop infusion with  first meal, regulate B/S with  subcut insulin until normal  regime can be implemented

Cardiac	Respiratory	Obesity
Pre-op: ECG ECHO: TOE or TTE Issues: Stenting and  anticoagulation : liaise with  cardiology What comes first: surgery v  cardiac disease Rx	Pre-op Respiratory consult Maximise respiratory fxn CXR, Peak flow, spirometry, Chest physio, nebs, inhalers Stop smoking >6/52 pre op Post-op Chest physio, chest physio,  chest physio Incentive spirometry Early mobilisation Nebs, inhalers Co-Morbitities	Pre-op Lose weight+++++ ? DM Stop smoking TEDS, LMWH++ Intra-op Suitable OT table Suitable surgical equipment High risk patients DVT prophylaxis Pressure sores Post-op Physio Dietician Mobilise

Anticoagulation

Aspirin

Nuseals or dispersible

Anti-platelet agent

• Irreversibly inactivates COX
• Blocks formation of  thromboxane A2 (prevents  platelet aggregation)
• Decreases PG synthesis
• S/E: PUD, tinnitus, Reyes  syndrome

Aspirin in surgery

• Should be stopped 5-7 days  prior to surgery unless  contraindicated ie cardiac  disease
• May need to liaise with  cardiology

Plavix (clopidogrel)

Anti-platelet agent

Used for CAD, PVD, etc

Blocks ADP receptor on  platelets

Inhibits platelet aggregation  by blocking glycoprotein  IIb/IIIa pathway

S/E: bleeding, TTP,  neutropaenia

Plavix in surgery:

Needs to be stopped 2/52  prior to surgery

May need to liaise with  cardiology

Warfarin

Uses: VTE, A Fib, APL syndrome, Artificial valves

MOA: inhibits vit K dependant synthesis of factors II,VII,IX and X

S/E:

• Haemorrhage
• Warfarin necrosis: paradoxic increase in coagulation: esp in Protein C deficiency
• OP
• Purple toe syndrome

Monitoring WEPPT : w arfarin, e xtrinsic p athway, p rothrombin t ime  (INR)

Warfarin in surgery

• Should be stopped 1/52 pre  op for low to medium risk  patients ie A Fib (or not  stopped in some hospitals)
• Never stopped in patients  with artificial valves- These patients come into  hospital 3-4/7 pre op to  stop warfarin and are  placed on IV heparin which  has much shorter t1/2 

Reversed by:

• Vitamin K (very slow)
• Prothrombin complex  concentrate
• FFP

IV or unfractionated  Heparin

• Binds to antithrombin,  which inactivates thrombin  and factor Xa
• Does not break down pre  formed clots (like tPA or  streptokinase)
• Half life of 1 hour: so each  hospital has protocol for  infusion
• APTT must be taken  regularly

Heparin in surgery

• Stopped 4 hours prior to  surgery for patients with  metal valves
• Recommenced post op with  warfarin and discontinued  when warfarin is in  therapeutic range (usually  3-4 days)
• Anticoagulation

Heparin S/E

• HITS : h eparin i nduced t hrombocytopaenia s yndrome
  • Platelets attacked by  immune system
• Raised liver transferases:  but no liver dysfunction

DVT Prophylaxis

Pathophysiology of DVT:

Virchows Triad

• Stasis
• Hypercoagulability
• Intimal injury

DVT Risk factors:

• Age >50
• Varicose veins
• Hx of MI, Ca, DM, ischaemic CVA, A Fib
• Pregnancy and obesity
• Immobility
• Surgery
• Hx of previous DVT
• OCP (stop 6/52 pre op)

Modified Wells Criteria

• Clinical sx of DVT: 3 pts
• Other Dx less likely: 3 pts
• Tachy: 1.5 pt
• Immobilization >3/7 or surgery within last 4/52 :  1.5 pts
• Previous DVT/PE: 1pt
• Malignancy: 1 pt
• Haemoptysis: 1 pt

Scoring:

High >6

Moderate 2-6

Low <2

Surgical Risk Groups for  DVT

Risk	Description	Prophylaxis
Low	Uncomplicated minor  surgery in patients < 40  with no risk factors GA < 30 mins	early mobilisation
Moderate	Any surgery in patients 40- 60 with no additional risk  factors Major surgery in patients <  40 requiring GA > 30mins Minor surgery in patients  with risk factors	TEDS and LMWH
High	Major surgery in patients  older than 60 years without  additional risk factors or  patients aged 40-60 years  with additional risk factors Patients with myocardial  infarction (MI) Medical patients with risk  factors	TEDS, LMWH and  intermittent pneumatic calf  compression
Highest	Major surgery in patients  older than 40 years with  prior venous  thromboembolism,  malignant disease, or  hypercoagulable state Patients with elective major  lower extremity orthopedic  surgery, hip fracture,  stroke, multiple trauma, or  spinal cord injury

LMWH

ie clexane (20mg sc) and  Innohep (3,500 u sc)

Given at night

Injection in lower abdomen

No need to monitor APTT

DRAINS IN SURGERY

Indications:

Exteriorize actual or  potential fluid collections in  a wound

Minimize dead space

Divert fluid away from  blockage (T –tube)

Decompression

Types

Open

• Non suction
• Corrugated or penrose

Closed

• Suction: ie Redivac
  • Adv: better drainage
  • Disadv: may damage  adjacent structures
• Non suction: Robinson,  Foley catheter

Complications

immediate  and early

• Air leak
• Pain
• Trauma at insertion
• Blockage of drain
• Disconnection if not secure

Late

• Infection
• Retraction
• Herniation
• Fistula
• Bleeding
• Anastomotic leak

Drains in surgery

NG

Chest drain

Operative wound drain

Pericardial drain

DIATHERMY

“passage of high frequency alternating currents between 2 electrodes and through tissue”

2 types

Monopolar	Bipolar
More common Very high current density @  tip Current passes from tip of  diathermy and dissipates  through the body to the  electrode stuck on patients  leg (70cm²)- ensuring  current density @ plate is  low, so minimal heating  occurs	Less common Used on terminal digits,  hand, penis : so large  current does not destroy  main nerves, vessels Current passed from one  electrode to another across  small amount of tissue Electrodes incorporated  into pair of forceps which  surgeon holds and  coagulates tissue No need for plate Much less powerful than  monopolar

Settings:

Cutting (only monopolar)

• High temp: 1000°C
• Tissue disruption, minimal  coagulation

Coagulation

• Pulsed output results in  sealing of vessels

Causes of burns:

Metal in contact with  patient: drip stand etc

Incorrect placement of  plate

• Needs good contact with  dry, shaved skin

• Contact area @ least 70cm  sq
• Away from bony  prominences : usually  placed on thigh

Careless technique

Use on large bowel:  methane + diathermy =  BOOM!

Use of monoplar on  appendages: penis, digits  etc

Used close to metal  implants : hip prosthesis

BLOOD TRANSFUSION

Good Transfusion Practice

Careful selection of donor

Test donated blood for known markers of disease (syphilis, HIV-1, HIV-2, HBV, HCV)

Patient's ABO and Rhesus group are determined

Cross matching- process where the red cells from the donor are tested against the serum from recipient to ensure compatibility

Blood and Plasma product

Product		Indications	Problems
Blood Product	Stored whole blood – blood with all constituent	Acute haemorrhage	Citrate anticoagulant, Acid pH, high K, ammonia
	Red cell concentrates– erythrocytes solutions without plasma + some WBC	Refractory anaemia	10% develop alloimmunization to leukocyte antigen
	Frozen red cells	Pt on renal dialysis, rare cell types and complex antibody mixtures	Very expensive
	Platelet concentrates- contains platelets derived from many donors	Stop bleeding in thrombocytopenic pt, to cover surgery if Plt < 40x109/L	Alloimmunization leads to progressive inefficiency
Plasma product	Fresh frozen plasma – prepared from supernatant liquid obtained by centrifugation of one donation of whole blood	Reversal of anticoagulant, correct isolated plasma protein deficiency, tx of DIC & burns	Allergic rxn, ARDS
	Cryoprecipitate (factor VIII, von Willebrand factor, fibtinogen)	Haemophilia, von Willebrand fisease, fibrinogen deficiency, bleeding, DIC	Risk of transmitted infection
	Factor VIII concentrate	Haemophilia	Allergic rxn. Hyperfibrinogenamia after massive dose
	Factor IX concentrate	Acute bleeding and perioperatively in Christmas disease	Allergic rxn

Adverse effects of transfusion

Complications

Early

• Haemolytic reactions (immediate or delayed)
• Bacterial infections from contamination
• Allergic reactions to white cells or platelets
• Air embolism
• Hyperkalaemia
• Clotting abnormalities

Late

• Infection - cytomegalovirus / hepatitis
• Immune sensitisation
• Iron overload

Acute Reactions	Cause	Treatment
Acute non haemolytic reaction	Alloimunization to leukocytes (commonest cause of pyrexia) Immediate hypersensitivity reaction	Immediate termination of transfusion. Treat anaphylaxis: iv crystalloid, maintain airway and O2, adrenaline (0.5mg im), iv antihistamine, salbutamol  nebulizer
Acute haemolytic reaction	ABO incompability. Pain at infusion site and along vein, chest and back pain, flushing, rigors and vomiting, SOB, hypotension, restlessness. Evidence of DIC	Immediate termination, replace giving set, iv crystalloid, forced diuresis with furosemide + mannitol, haemodialysis, treat hyperkalaemia (dextrose50% +10 units insulin if K > 6mmol/L), treat DIC, investigate incident
Transfusio-related lung injury	Donor blood antibodies reacting with pt's leukocytes lead to ARDS	Resp support. May need ventilation with positive end-expiratory pressure (PEEP)
Metabolic, haemostatic and resp. complications	Massive transfusion volume (>pt's blood volume over 12h)	Hypothermia (tranfuse warm blood), metabolic acidosis (may need NaHCO3), impaired release of O2 from RBC (self limiting, no therapy), citrate intoxication → hypocalcemia (self limiting, no therapy), Hyperkalemia (seldom a serious prob), platelet and clotting factor deficiency (2 units FFP for every 8 units blood)
Circulatory overload	Seen with transfusion of anaemia	Use only RBC concentrates, diuretic therapy
Transfusion of bacterially contaminated blood	Rare. Usually after platelet transfusion. Pseudomonas fluorescens, Yersinia enterocolitica	Full resuscitaion and management in ICU for septic shock. Despite therapy, mortally, mortally is 60%
Delayed reactions	Comment
Transmission of infectious disease	A wide spectrum of infectious disease can be transmitted by blood transfusion. Risk is very small
Immune suppresion	Perioperative blood transfusion enhances risk of infection and may adversely affect outcome in cancer
Transfusion haemosiderosis	Iron overload of the monocyte/macrophage system occurs after 100 units of blood have been transfused over years. Tx: Iron chelation with desferrioxamine
Graft vs host disease	Immunologically competent transfused cells attack the host environment. May occur when immunodeficient pt are transfused. Rare but fatal

Disseminated Intravascular Coagulation

Results in

• activation of clotting cascade
• Bleeding due to consumption of clotting factors

May present with

• Bruising
• purpura
• Oozing (may be noticed during surgery)

Caused by

• Severe infection (meningococcal)
• metastatic adenocarcinoma
• shock
• Burns
• Transfusion reactions

Investigation

• Increased APTT and PT
• Reduced serum fibrinogen levels (<1 mg / ml)
• Thrombocytopenia

Management

• Treat underlying cause
• Supportive treatment with fluid and blood products including platelets, cryo and FFP

WOUND CARE

WOUND HEALING

Healing by primary Intention

• Eg- healing of uncomplicated skin incision
• No necrotic tissue  and the margins of the wound are brought into apposition with sutures
• An acute inflammatory response develops in the immediate vicinity of the incision
• By the 3rd day, granulation tissue bridges the dermal defect.
• Proliferating surface epithelium rapidly restores the epidermis from the wound edges.
• Fibroblast invade the granulation tissue, laying doen the collagen so the repair will be strong enough to permit suture removal after 5-10 days
• At this stage, the scar is still red but blood vessels slowly regress
• It becomes a pale linear scar within a ferw months.

Healing by secondary intention

• Tissue loss prevents wound edge from coming together
• The defect is initially filled with blood clot.
• This later is invaded by vascular granulation tissue from wound base
• Inflammatory exudate solidifies at the surface forming a protective scab
• Fibroblast invade the granulation tissue and collagen is laid down in the extracellular spaces
• week 1: fibroblast differentiate into myofibroblast and
• week 2: weontraction of their myofibrils eventually shrinks the wound defect by 40-80%
• week 3 to months: blood vessels regress and more collagen is formed, leaving a relatively avascular scar; gradual contraction of the mature collagen (cicatrisation), combined with wound contraction
• The overlying epidermal defect is gradually  bridged by epithelial proliferation from the wound margins.
• Epithelial cells slide over each other beneath the edges of the scab upon the surface of the granulation tissue.
• The scab is shed

Factors influencing wound healing

Local

• Foreign body
• Unsuitable dressing
• Necrotic tissue
• Malignant invasion
• Interference by patient

Regional

• Arterial insufficiency – causing chronic ischaemia (lower limb)
• Venous insufficiency
• Late side effect of radiotherapy- due toendateritis obliterans (less likely with modern techniques), bowel particularly affected

Systemic

• Malnutrition- hypoproteinaemia; vit. C and zinc deficiencies
• Anaemias
• Immunosuppression -HIV, cytotoxic drugs, radiotherapy
• Corticosteroids
• Social – alcoholism, IVD abuse, general neglect
• Metabolic disease – renal, hepatic failure
• Endocrine disease – uncontrolled DM
• Autoimmune disorder – rheumatoid
• Collagen disorder- Marfan's, Ehlers-Danlos
• Carcinomatosis/cachexia

SURGICAL INFECTION

Postoperative Infections

Dx: pyrexia is a common sign of infection, A mildly raised temperature  is normal in early post-op – response to surgery

Note

Onset : first 24h usually atelectasis

Degree and type:

a) Low persistent: low grade infectivity or inflammatory process

b) intermittent: abscess + rigors or haemodynamic change (bacteremia/septicaemia)

Check

Lungs (atelectasis/pneumonia)

Wound (infection)

Calves (DVT)

Urine (infection)

Inravenous or central lines

Investigation

Septic screen

Urine specimen

Sputum sample

Swabs of wounds or cannulae

Blood cultures

CXR + other imaging as indicated, eg abdominal US or CT scan if peritonitis present

Treatment

Give Antibiotics on basis of most likely organism (refine treatment when septic screen results available)

Treat cause as appropriate, eg remove infected cannula, drain abscess surgically or radiologically, give chest physiotherapy and respiratory support, deal with anastomic dehiscence

Specific Surgical infections

Infections	Description	Management
Cellulitis	Acute pyogenic cellulitis (Streps pyogenes)	Immobilization, elevation of affected part and iv ab- penicilin, erythromycin
	Anaerobic cellulitis = aerobic+ anaerobic. eg. Progressive bacterial synergistic gangrene (Fournier's gangrene), Necrotising fascitis	Surgery to remove necrotic tissue. Ab (combi of flucloxacilin, benzylpenicilin, cephalosporins, erythromycin or gentamycin for aerobes. Metronidazoles for anaerobes. Support in ICU
Staphylococcal infections	Furuncle(boil) -skin abscess involving hair follicle Style- Infection of eyelash follicle Carbuncle -subcutaenous necrosis with network of small abscesses Sycosis barbae -infection of shaving area caused by in infected razor Hidradenitis suppurativa- infection of apocrine glands in skin (axilla, groin)
Tetanus (Clostridium tetani)	Penetrating dirty wounds Most symptoms caused by exotoxin, which is absorbed by motor nerve endings and migrates to anterior horn cells Spastic contractions and trismus (lockjaw) Spasm of facial muscle (risus sardonicus) Rigidity and extensor comvulsions (opisthotonus)	Antibiotic (penicilins), artificial ventilation with muscle relaxation, antitetanus immuoglobulin Prophylaxis: Immunization as a child :  Dtap Should have top-up of tetanus toxoid  q 10 yrs If in doubt of immunization, patient  needs tetanus immunoglobulin Age appropriate vaccination  schedule
Gas gangrene	Clostridial infection caused by C. perfringens (65%), C. navyi (30%), C. septicum (15%) Comtamination of necrotic wounds with soil containing clostridia Spreading gangrene of muscles, with crepitus from gas formation, toxaemia and shock.	Wide local excision or amputation with free drainage and high dose ab (penicilin, metronidazole), hyperbaric oxygen

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