General Surgery Flashcards
What is a clean procedure?
The operative procedure does not enter a colonised viscus or lumen of the body e.g. elective hernia repair
Surgical site infection entirely due to contaminants from the environment / surgeons - mainly S.aureus, with a rate of 2-5%
What is a potentially contaminated procedure?
The operative procedure enters into a colonised viscus or body cavity but under elective and controlled circumstances
SSI risk is from endogenous bacteria, with a rate of 10%
What is a contaminated procedure?
Contamination is present at the surgical site without obvious infection e.g. intestinal spillage due to penetrating injury
SSI risk is from endogenous bacteria, and stands at 20%
What is a dirty procedure?
Surgery performed where active infection is already present, e.g. abdominal exploration for intra-abdominal abscess and perforation
Infection risk is from already established pathogens and stands at 30%
What is rigid proctoscopy?
endoscopic examination of the anal canal using a proctoscope (direct vision)
What is rigid sigmoidoscopy?
Endoscopic examination of the rectum to the recto-sigmoid junction, using a rigid sigmoidoscope (direct vision)
What are the indications of rigid sigmoidoscopy?
Suspicion of colonic neoplasia Investigation of inflammatory bowel disease Biopsies under direct vision treatment of haemorrhoids Prior to any ano-rectal operation
What is flexible sigmoidoscopy?
Endoscopic examination visualising up to the splenic fixture
What are the indications for flexible sigmoidoscopy?
Colorectal cancer screening
Surveillance of previously diagnosed malignancy
Endoluminal stent insertion for strictures
pre-operative assessment before anorectal surgery
Haematochezia (passage of frank blood per rectum) requiring haemostasis
What are the indications for tube thoracostomy (chest drain)?
Pneumothorax
pleural effusion / empyema
Post operative (thoracotomy, oesophagectomy, cardiac surgery)
How is a tube thoracostomy inserted?
Inject LA to infiltrate skin and parietal pleura
make 2cm incision near upper border of lower rib (avoiding neuromuscular bundle) in triangle of safety
Blunt dissect to parietal pleura and then palpate lung with gloved finger to free adhesions
Insert drain and attach to underwater seal, suturing in to the chest wall
Apply airtight dressing and sit patient up to 45 degrees
Check position with CXR and repeat CXR daily
Drain should swing (change in fluid level of tube) with respiration and bile in pneumothorax
Where is the triangle of safety?
Between lateral border of pec major and lat doors, superior to the 5th intercostal space, inferior to the axillary border
What is a stoma?
An external opening in a lumenated organ
What is an ileostomy formed from?
SMALL BOWEL
Describe the features of an ileostomy?
Spouted - with prominent mucosal folds Tends to be on RHS Bilious contents of the bag One/two visible lumens If one visible lumen: end ileostomy
if two visible lumens: loop ileostomy
What are the indications of an end ileostomy?
PERMANENT - after removal of distal bowel
Indications: definitive surgery to remove colon in UC
What are the indications of a loop ileostomy?
TEMPORARY: reversed at a later date
indications: to rest distal bowel e.g in IBD
to temporarily protect distal anastomoses following surgery
To provide functional relief from severe incontinence
What is a colostomy formed by?
Large bowel
What are the features of a colostomy?
Usually flush to the skin, with flat mucosal folds
tend to be on the left hand side
Contents tend to be more faeculant
Again - can be loop or end
Which are more common, loop or end colostomies?
END - after a variety of large bowel operations:
After what surgeries might there be an end colostomy?
Hartmann’s procedure: temporary end colostomy after emergency large bowel surgery
Left hemicolectomy: may require temporary end colostomy prior to colo-colic anastomosis at a later date
Abdomino-perineal resection: surgery for rectal pathology, with removal of back passage and permanent end colostomy
What is a urostomy formed by?
From a short section of disconnected ileum, into which one or both ureters are directed after radical urinary tract surgery
Indistinguishable from an end ileostomy unless output can be seen
What is a gastrostomy?
Connection from the anterior stomach to the anterior abdominal wall
Often for stomach drainage or direct feeding
What are the features of a gastrostomy?
Narrow in calibre
Flush to the skin
usually in the LUQ and fitted with indwelling access devices
What is a jejunostomy?
Connection from the jejunum to the abdominal wall, for direct feeding
Appearances = same as a gastrostomy
What are the early complications of a stoma
Infarction / necrosis
Infection
High output from the stoma leading to severe dehydration
What are the late complications of a stoma?
Parastomal hernia: incisional hernia at the stoma site
Stoma prolapse: underlying bowel protrudes through the orifice
Stoma retraction: the stoma is drawn / pulled below skin level
Stenosis: narrowing of the stomal opening
What are the steps of examination of a stoma?
Ask if there’s any pain
palpate abdomen for any distension or tenderness
ask to cough - any parastomal hernias?
Observe surrounding skin: any signs of infections?
Determine type: siting, spouting and contents
Any signs of infarction, prolapse or retraction
Listen for bowel sounds below the umbilicus
State you would like to look at the patient’s fluid balance chart
What are the indications for urethral catheterisation?
Acute/chronic urinary retention
Output monitoring (in critical illness/perioperative patients)
Incontinence
To aid surgery
What are the contraindications for urethral catheterisation?
Urethral injury e.g. pelvic fracture or acute prostatitis
What size catheter is used for females?
12
What size Catheter is used for males?
14
How should a catheter be managed?
Clean catheter tube and site of entering the body twice daily
Change leg/night bag at least once weekly
Use appropriate leg straps / catheter sleeve to secure the catheter
Empty catheter bag when 2/3 full
What is the indication for suprapubic catheterisation?
Mandatory in patient with pelvic trauma and suspected urethral injury
Bladder must be distended to prevent peritoneal penetration, and the catheter is then passes over a tracer after Local anaesthetic infiltration
USS guided drainage may also be used
What are the complications of urethral catheterisation?
Retrograde infection Paraphimosis (if fail to reduce the foreskin post-procedure) creation of false passages Urethral strictures Urethral perforation Bleeding
How should urine be sampled from a catheter?
Specimen obtained aseptically from a port in the catheter tubing or by aseptic aspiration of the tubing
never collect from the catheter bag
Where are the two locations of drains?
Superficial (placed in the wound) or deep
What are active drains?
Involve suction forces provided by vacuumed containers and are used to draw out collections
What are passive drains?
function by differential pressures between the body and the exterior e.g. using gravity these pressure can sometimes become reversed - with the risk of introducing external bacteria
Open drains are always passive - leading to a dressing or stoma to provide a conduit around which secretions can flow. they may be tubes or corrugated sheets.
What is a closed drain?
Tube systems that drain effectively into a container with or without suction (active or passive)
What are the indications for placement of a drain?
TO remove existing abnormal collections of fluid, blood, pus or air
To prevent build up of bodily fluids (e.g. bile), abnormal fluids or air
to warn of potentially serious complications
When should a drain be removed?
Depends on the purpose of the drain e.g. by 48 hours if covering peri-operative bleeding, by day 7 if covering intestinal anastomoses
What are the common complications of drains?
Damage to structures during insertion - avoided by image guided insertion
Damage to structures due to pressure effects of the drain
Infection: avoided by timely removal of the drain
Failure of the drain - which can give a ‘false sense of security’, so proper observation of the patient’s clinical state is still necessary
What are the indications for a Central venous catheter?
Critically ill patients requiring continuous CVP monitoring (of fluid status)
Infusion or irritant substances
Precise infusion of substances with a very narrow therapeutic window
Long term access for parenteral nutrition, chemotherapy or antibiotics
Haemodialysis
No other venous access available
What are the different types of central venous catheters?
Hickman
PICC line
Portacath
What is a Hickman Line? Where is it placed?
Tunnelled beneath the skin for stability and to prevent infection, generally at the IJV on the right, however can be either side
What is a PICC line? where is it placed?
Peripherally inserted central catheter, inserted in the arm (cubital fossa, brachial vein) and advanced to the SVC
What is a portacath? Where is it placed?
Port installed beneath the skin, and connected to a vein by a catheter
What are the complications of a central venous catheter?
Haemorrhage / arterial puncture Pneumothorax Thoracic duct damage air embolism Thrombosis Catheter-related sepsis
What is a Swan-Ganz catheter?
Balloon catheter, passed from the femoral vein, through the right side of the heart into the pulmonary artery to measure pulmonary artery pressures
Can also be advanced to wedge a smaller pulmonary vessel, giving the pulmonary wedge pressures (high pressures indicate LV failure)
What are the indications of a Swan-Ganz catheter?
Assessment of haemodynamic response to therapies (ITU)
Monitoring of complicated MI / post-cardiac surgery
Diagnosis of high vs low pressure pulmonary oedema
Diagnosis of idiopathic pulmonary HTN / PE
What are the complications of a Swan-Ganz catheter?
Arrhythmia
Valve trauma
Pulmonary infarction / pulmonary artery rupture
What is the indication of arterial catheterisation?
Frequent blood sampling / ABG analysis
Continous invasive BP monitoring
Where are arterial catheters inserted?
Radial artery
How Is Allen’s test performed?
Elevate hand, ask patient to make a fist whilst occluding the radial and ulnar arteries for 30s
Ask patient to open hand (should be blanched)
Release the ulnar pressure - colour should return in 7 seconds, indicating sufficient ulnar arterial supply to the hand
What are the complications of ABG puncture?
Digital ischaemia
Thrombosis
Haemorrhage
How should central venous lines be monitored?
Report any signs of infection / bleeding
DO not get site wet
Avoid contact sports
What are the stages of wound healing?
Haemostasis (immediate)
Inflammation (0-3 days)
Proliferation (3 days - 3 weeks)
remodelling (3 weeks to 1 year)
What occurs in the first stage of wound healing?
Haemostasis (immediate)
Platelets aggregate at the site in response to exposed collagen, releasing inflammatory markers and activate clotting and complement cascades.
Haemostasis is then achieved by vasospasm and thrombus formation
What occurs in the second stage of wound healing?
Inflammation (0-3 days)
Vasodilation and increased capillary permeability allow inflammatory cells to enter the wound, leading to oedema
Neutrophils enter the tissues to debride and kill bacteria, followed by macrophages to phagocytose the debris and orchestrate fibroblast migration
What occurs in the third stage of wound healing?
Proliferation (3 days-3weeks)
Fibroblasts migrate in to synthesise collagen, with myofibroblasts secreting actin-containing products to cause wound contraction
Angiogenesis is stimulated by hypoxia, and also the cytokines secreted by neutrophils and macrophages. This creates granulation tissue
Wha occurs in the fourth stage of wound healing?
remodelling (3 weeks to one year)
re-orientation and maturation of collagen fibres to increase wound strength
What is granulation tissue?
the combination of capillary loops and myofibroblasts, giving the appearance of small, red foci that bleed easily (newly formed capillary loops), commonly seen when a scab is picked
What is the function of granulation tissue?
allows all the inflammatory cells to enter the damaged issue to promote defence and healing
What is the presentation of infected granulation tissue?
Painful discharging, erythematous and swollen, and the patient may have systemic features
What is epithelialisation?
The covering of a denuded surface (skin layers removed) with epithelial tissue, occurring from the outer edges of the wound after granulation
What is primary intention healing?
Where there is close apposition of clean wound edges:
Thrombosis in cut blood vessels prevents haematoma formation
Coagulated blood forms a surface scar to keep the wound clean
Fibrin is able to form a weak framework between the edges over which capillaries proliferate and secrete collagen into the fibrin network
The elastic network of the dermis cannot be replaced
What is Secondary intention healing?
Takes place in wounds where skin edges cannot be clearly opposed
Phagocytosis removes debris and granulation tissue forms to fill the defect
Epithelial regeneration then covers the surface
In which type of healing is there greater loss of tissue?
Secondary intention healing
What are the factors affecting wound healing?
Age, diabetes, nutrition, smoking, HGH evens, infection and other inflammatory conditions such as RA
When can wounds be closed safely?
When can they not?
Safe closing: tidy wound that is less than 12 hours old e.g. lacerations, abrasions and injuries with minimal skin loss
Cannot: ‘untidy’ - marginal necrosis, crush injuries or tearing injuries with skin loss.
These require wound excision with removal of debris / dead tissue
When is delayed closure indicated?
If they are more than six hours old or heavily contaminated, where the wound will be dressed and inspected daily for further necrosis of inflammation.
The wound will then by closed at 48-72 hours if it is satisfactory
How should abdominal wounds be closed?
Properly! avoid dehiscence and herniation Mass closure (continuous fascial closure with single suture) for a midline incision with 1cm bites 1cm apart
Layered closure for other abdominal incisions
Sutures should be removed at 10 days
What are the inflammatory changes around a wound/suture?
Calor (heat) rubor (erythema) tumour (swelling) Dolor (pain) Function laesa (loss of function)
What is the management of an infected surgical wound?
May need no tx
Oral / IV abx alone, or reintervention on the ward / in theatre to open, drain, decried, rinse and pack wound.
Cultures always recommended
ABG normal results:
pH: 7.35-7.45
PaO2: >10.6 kPa
PaCo2: 4.7-6 kPa
Base excess +/- 2
What are the electrolyte values of serum?
Sodium: 135-145 Potassium: 3.5-5 Calcium: 2.2-2.6 Chloride: 94-111 Lactate: 1-2
How much dextrose does 5% dextrose contain?
50g in 1L of pure water
What is a colloid?
Rarely used
Gelatin/albumin solutions: large molecules dispersed in a solution that theoretically keep more fluid in the intravascular compartment during resuscitation
How do you calculate total body water?
0.6 x bodyweight
How is fluid divided in the body?
Extracellular fluid (ECF) = 1/3 of total body water Intracellular fluid (ICF) = 2/3 of total body water
How is extracellular fluid divided?
Interstitial fluid: 3/4 of ECF
Plasma: 1/4 ecf
small amount is transcellular fluid (CSF, peritoneal, synovial)
Who has more water than a normal man?
Neonates: 80%
children: 70%
Women and obese men: 50% water
What are sensible/insensible losses?
Sensible: urinary
Insensible = sweat, lungs and faeces
Additional: NG, drains, stomas, third space losses
how should daily fluid requirements be prescribed
25-30 ml/kg/day of water
1mmol/kg/day of sodium and potassium
50-100 g/day of glucose to limit starvation ketosis
SO: between 2 and 3L/day
1 salty 2 sweet:
1L normal saline (with KCL added if they need it!) over 8 hours
1L 5% dextrose (with KCL added) over 8 hours
1L 5% dextrose (with KCL added) over 8 hours
How should paeds fluids be calculated?
100ml/kg/day for first 10kg
50ml/kg/day for second 10kg
25ml/kg/day for any more weight after that
How should fluids be given if the patient has a fever?
add 10% more fluid for each degree of fever
