surgical talk Flashcards
causes of obstruction of any hollow tube
extramural
intramural
luminal
causes of bowel obstruction
extramural
- adhesions, strangulated hernia, extrinsic compression, volvulus
intramural
- inflammation eg crohns, tumours, infarction, strictures
luminal
- impacted faeces, large polyps, foreign body, intersusception
topics to cover when discussing complications of any procedure
general operation, specific to this op.
immediate, early, late
causes of haematuria
anatomical
kidney - stones, trauma, carcinoma
ureter - tumour, stones, infection
bladder - same
prostate - benign hypertrophy, tumour, infection
urethra - same e.g. tumour, stones, infection
hx of a lump
when and how did you first notice it? how has it changed since you first noticed it? what symptoms does it cause you? have you got any more? have you had this before? what do you think it is?
why is dextrose rubbish for resuscitation
it distributes throughout all the fluid compartments including the cellular fluid and thus only 3/42 of the volume given will remain in the plasma. saline only distributes throughout the extracellular fluid, of which the blood is 1/3 and thus 1/3 stays intravascular. colloids by comparison should stay fully within the vascular compartment.
minimum volume of urine production in a health patient
0.5ml-1ml /kg/hr
maintenance fluid protocols
1 - 3litres of dextrose saline with 20mmol of K added to each litre. result = 3l water, 90mmol Na, 60mmol K. this may be too little Na over several days.
2 - 1 litre 0.9% saline, 2litres 5% dextrose, all with 20mmol K added. result = 3l water, 150mmol Na, 60 mol K
if you run each bag over 8 hours then that will cover the whole day.
effect of the postoperative period on fluid balance
HPA axis activation causes renal conservation of Na and water, with increased losses of K and H ions. despite the increased K loss this is normally maintained or may go up due to K lost from damaged cells. this lasts for 24-48 hours. additionally if there is ileus then there will be water retained in the gut, when this restarts you’ll get a marked diuresis as it is resorbed. the result of these considerations are that you’ll often limit fluid input to 2l for the first couple of days, but check this with clinical signs of dehydration as any ileus may counteract the retention and mean you need more fluids.
consider all other losses as well, such as draining wounds.
effect of heart or liver failure on fluid demands.
the RAAS is in overdrive, causing Na retention, so mainly use 5% dextrose. have to monitor these patients carefully as you may have to stop fluids or even prescribe diuretics to prevent overload.
signs of overload might be raised JVP, oedema inc pulmonary.
effect of a unit of packed red cells on Hb
will raise by just under 1g/dl
what is parenteral nutrition
bypasses the gut and involves a specialised feed directly into the patients blood stream. TPN = total parenteral nutrition. usually given via a small cannula into a large vein with high flow rate as the osmolality is toxic. central venous line is usually used. a hickman line for longer term use as this is tunnelled under the skin to be more secure and has a Dacron cuff to block infection.
what are enterocytes
the gut luminal cells.
daily requirements of a patient
water 2-3l a day energy - energy 1800 calories nitrogen - 14g protein a day vitamins - titrate minerals eg Na and K tace elements eg zinc, copper and iron
causes of postoperative pyrexia
the 7 Cs 1 - chest infection 2 - catheter UTI 3 - CVP line infection 4 - cannula - thrombophlebitis 5 - cut - infection 6 - collection - subphrenic and pelvic abcessess 7 - calves - DVT
how do you manage a postoperative patient that has a poor urine output?
can be due to pre-renal, renal or post-renal causes. post-renal are most common.
pre-renal :
- renal hypoperfusion due to hypovolaemia or heart failure.
renal:
- acute tubular necrosis
post-renal:
obstruction due to prostate or blocked catheter. difficulty initiating due to: anticholinergics, alpha-adrenergics (e.g. some anaesthetics), pain, psychological, opiates, epidural anaesthetics.
management:
conservative - analgesia, privacy. catheterisation. check the fluid balance charts. check U and Es as urea will be raised in pre-renal causes. if you think its pre-renal try a fluid challenge. if its renal then creatinine will be raised.
if a PT is thirsty, has dry mucous membranes, loss of skin turgor etc what does this suggest and how do you manage it?
may also have tachycardia and poostural hypotension - suggests a loss of 5-15% total body water, less than 5% is tough to detect. over 15% loss and there is noticeable circulatory collapse. you then need to replace this like for like.
complications of TPN
sepsis (but to reduce the chance of this the central venous catheter is tunnelled with a subcutaneous dacron cuff at the exit site to reduce the risk of infection.)
also thrombosis, hyponatraemia and hyperglycaemia esp following pancreatitis.
what needs to be considered about a PT with diabetes that is going to have surgery?
how their blood glucose is going to be controlled. if they are diet controlled then that is fine. if they are insulin controlled then they should stop their insulin and should be put on a glucose and short acting insulin infusion. this prevents intraoperative hypoglycaemia. they should also be placed first on the list for the day so they spend the minimal amount of time fasting.
surgical considerations for the patient on warfarin or who has had a previous thromboembolic event
if on warfarin then this should be stopped and converted to heparin.
if they have had a previous thromboembolic event then they should be given additional prophylaxis including TEDS and compression boots whilst on the table and early mobilisation.
what objective assessments of operative risk and mortality are there?
the ASA score is one thats good for preoperative assessment. others that are sometimes used include APACHE (although this is more for looking at how ill they are than surgical risk per se), and P-POSSUM.
breakdown of the ASA score
american society of anaesthesiologists
grades 1-5 with a estimated mortality rate of less than 0.1% to over 50% respectively.
1 = normal and healthy
2 = mild systemic disease that doesn’t limit activity.
3 = severe systemic disease that limits activity
4 = incapacitating systemic disease which is constantly life threatening
5 = not expected to survive 24 hours, with or without surgery.
risk of postoperative wound infection - stratification and odds?
1 - clean - unaffected operative wound with no viscera being opened - risk less than 1%
2 - clean contaminated. a viscous is opened but there is little to no spillage - less than 10% risk
3 - contaminated - obvious spillage or inflammation e.g. gangrenous appendix. infection rate of 15-20%
4 - dirty or infected - gross contamination e.g. perforated large bowel. infection risk is over 40%
principles of antimicrobial prophylaxis
1 - antimicrobial selection in order to target the flora likely to be encountered.
2 - treatment before contamination occurs so that there is an adequate concentration of antibiotic in the blood at time of exposure.
