Covers all topics Flashcards
What are the indications and types of preoperative prophylactic antibiotics used?
Class I wounds:
- breast cancer
- cardiac procedures
- carotid endarterectomy
- haemodialysis access
Class 2 wounds:
single preoperative dose <60mins before knife to skin
Class 3/4 wounds:
single preoperative dose, may repeat at 4-6 hours depending on abx used and length of case and usually continue post op.
Skin cover e.g. hernia repair:
- cephzol
Upper enteric bacteria e.g. gastroduodenal surgery need cover GNB and GPC
- cephzol
Lower enteric bacteria e.g. colonic surgery need cover for GNB, GPC and anaerobes
- cephzol + metronidazole
Biliopancreatic surgery e.g. cholecystectomy, pancreatic procedures need cover for GNB, GPC and clostridia
- cephzol
In penicillin or cephalosporin allergy:
GPC & Anaerobe Coverage:
- Clindamycin
- Vancomycin
GNB Coverage:
- Gentamicin
- Ciprofloxacin
What is the anaerobic threshold for surgery?
What are the main nutrients for enterocytes and colonocytes?
glutamine and butyrate respectively.
What are some malnourishment screening or assessment tools?
MST - Malnutrition Screening Tool - looks at weight lost in last 6 months and appetite
SGA - Subjective Global Assessment is more in-depth and in addition to MST looks at what diet is made up of, symptoms including nausea, vomiting, bowel habit etc, functional capacity and then a physcial assessment looking at sub cut fat under the eyes, sides of trunk, around scapula etc and for muscle wasting e.g. at temple, clavicle, interosseous sites and fluid retention.
MUST- Malnutrition Universal Screening Tool
What are some dietary supplement drinks?
Fortisip
Ensure
Sustagen - low GI, higher protein, lower fat
diasip - lower cal
ensure 2calhn - 400g in 200ml good for fluid restricted pts
fortijuice - COF
What are some complications of parenteral nutrition?
Related to the central venous catheter:
- pneumothorax
- bleeding
- misplacement or migration
- infection (bacteraemia, endocarditis)
- thrombosis & thrombophlebitis
- on removal piece of catheter broken off
- arrythmias
Related to the feed and its processing:
- abnormal liver function tests and cholestasis
What are the goals of parenteral nutrition?
Maintain lean body mass. (rarely can we achieve an increase in body mass)
Provide energy for basal metabolism and activity
Provide macro and micro-nutrients for healing
What is refeeding syndrome?
The clinical complications that occur as a result of the fluid and electrolyte shifts during aggressive nutritional rehabilitation of malnourished patients.
It is marked by:
- hypophosphataemia
- hypokalaemia
- hypomagnesaemia
- congestive heart failure
- peripheral oedema
- rhabdomyolysis
- seziures
- haemolysis
- respiratory insufficiency
- diarrhoea
Pathogenesis:
During starvation phosphate stores are depleted. During initiation of feeding with carbohydrates insulin is released»_space; resulting in cellular uptake of electrolytes phosphate, potassium and magnesium»_space; in addition phosphate is required for production of ATP (Adenosine Triphosphate) which further depletes intravascular phosphate.
If phosphate becomes too low then the inability to phosphorylate certain proteins can lead to tissue hypoxia , myocardial dysfunction and respiratory failure due to diaphragm not able to contract and rhabdomyolysis.
In addition malnourished patients are often thiamine deficient and then with refeeding intracellular uptake of electrolytes leads to increased utilisation of thiamine»_space; further depleting it. can lead to Wernicke encephalopathy
Diarrhoea is a common symptom due to atrophy of the intestinal mucosa and pancreatic exocrine insufficiency. Generally resolves after a few weeks as villous surface is restored.
How do you manage someone with central venous catheter related sepsis (line sepsis)?
- Stop parenteral nutrtion
- Cultures from line and seperate site.
- IV antibiotics
- If unstable may need to remove the line or if s.aureus or fungal line will need to come out as unable to clear from the line.
- 70% ethanol locks
How can you diagnose a line sepsis from the cultures?
Differential time to positivity. If the central venous catheter line grows in the lab earlier than the peripheral by 2 hours or greater its highly predictive. If less than 2 hours difference more likely to be a bacteraemia from another source.
When restarting enteral feeding after a prolonged period without what are some considerations/methods to use?
Best off starting with complex polymeric feeds rather than elemental (lower osmotic load - elemental has higher osmotic load will increase output through the gut in high output stomas/high enterocutaneous fistulas.).
Tend to avoid concentrated sugars and fruit juices for same reason
Dairy fine as the diassacharidases etc are in duodenum and can be processed ok and need a good source of calcium.
What are the patterns of liver function derangement with parenteral nutrition? How do you treat it?
Early - steatosis
- first week or two
- reversible
(either do nothing or reduce glucose)
Late - cholestasis
- after several weeks or months
- avoid sepsis
- cycling the IVN (i.e. give TPN free periods, e.g. 12h on, 12h break)
- ursodeoxycholic acid
- metronidazole (to treat intestinal overgrowth)
- medium chain lipids
- fish oil
How are carbohydrates digested and absorbed?
Digestion begins in mouth with salivary amylase (inactivated in stomach) and resumes in small intestine with pancreatic amylase.
They are absorbed as monosaccharrides by secondary active transport except fructose by facillitated diffusion.
What are essential fatty acids?
These are fatty acids essential to human life that are not produced in the body and must be consumed.
These include linolenic acid & alpha linolenic acid.
Without these people can develop diffuse waxy dermatitis, thrombocytopaenia, intellectual disability and alopecia.
How are fats digested and absorbed?
Digestion begins in the mouth with lingual lipase. Bile and pancreatic lipase breakdown triglycerides to fatty acids. Fatty acids aggregate into micelles.
Fatty acids then diffuse across small intestine cell membranes and reassemble into triglycerides. Triglycerides and cholesterol combine to form chylonmicrons. These are then absorbed directly into lacteals into lymphatics then into bloodstream.
