Nir Hus Absite review q3 4

19
Absite topics 7-12 Nir Hus Nir Hus

description

Slides with topics that are covered and were tested in the recent Absite exams.Nir Hus MD., PhD.http://www.nirhus.com

Transcript of Nir Hus Absite review q3 4

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Absite topics 7-12

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Q7: Timing of the first prophylactic antibiotic dose

The first prophylactic antibiotic dose should provide a sufficient antibiotic serum level throughout the surgery to combat organisms most likely to cause a site infection.

The first dose be timed to occur within 60 minutes before the surgical incision is made.

If a fluoroquinolone or vancomycin is chosen for prophylaxis, the first dose should be administered within 120 minutes of the start of surgery.

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Timing of the first prophylactic antibiotic dose

For most surgeries, the use of prophylactic antibiotics should end within 24 hours after surgery.

Cefazolin or cefuroxime are suggested for cardiothoracic surgery, with the recommendtion of extension of prophylactic antibiotics up to 72 hours to avoid deep sternal infections.

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Surgery Prophylaxis CommentsCardiothoracic Cefazolin or cefuroxime; if

beta lactam allergy, vancomycin or clindamycin

72-hour duration advocated by some, but 24 hours is likely to be adequate

Vascular Cefazolin or cefuroxime; if beta lactam allergy, vancomycin with or without gentamicin, or clindamycin

Colon Oral: neomycin, with erythromycin base or metronidazole

Combination of oral and parenteral prophylaxis may decrease infection rates

Adapted with permission from Bratzler DW, Houck PM. Antimicrobial prophylaxis for surgery: an advisory statement from the National Surgical Infection Prevention Project. Clin Infect Dis 2004,38:1707.

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Timing of the first prophylactic antibiotic dose

Adapted with permission from Bratzler DW, Houck PM. Antimicrobial prophylaxis for surgery: an advisory statement from the National Surgical Infection Prevention Project. Clin Infect Dis 2004,38:1707.

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Q8: Incarcerated Groin Hernia

Incidence of incarceration ~10% among inguinal hernias.

Cannot be reduced into the abdominal cavity.

Strangulated hernias have incarcerated contents with vascular compromise.

Frequently, intense pain is caused by ischemia of the incarcerated segment.

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Q8: Incarcerated Groin Hernia

Incarcerated inguinal hernias present with abdominal distention, pain, nausea, and vomiting due to intestinal obstruction.

Plain abdominal X-rays may verify intestinal obstruction in cases of incarceration.

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Q9: Short Bowel Syndrome

Pathophysiology:DehydrationElectrolyte derangementsAcidic diarrheaSteatorrheaMalnutririonWeight loss

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Q9: Short Bowel Syndrome

Etiology for extensive resection: Congenital anomalies leading to short bowel syndrom include –

Intestinal atresia Midgut volvulus w/ intestinal necrosis Necrotizing enterocolitis.

In Middle-aged adults – IBS Trauma

In the elderly- Mesenteric ischemia Strangulated hernia Extensive resection due to malignancy.

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Q9: Short Bowel Syndrome

Resection resulting in less than 120cm of intact bowel leads to SBS.

Resection of up to 50% of small bowel is tolerated.

Resection of up to 70% is tolerated if terminal ileum and cecum are preserved.

Infants may tolerate upto 85% of small bowel resection.

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Q9: Short Bowel Syndrome

Loss of the ileocecal valve results in rapid emptying of enteral contents into the colon and reflux of colonic bacterial flora into small bowel.

The entire jejunum can be resected without serious adverse nutritional sequela.

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Q9: Short Bowel Syndrome

Adaptation:Cellular hyperplasia and bowel hypertrophy

occur over a 2- to 3-year period, increasing the absorptive surface area.

Fat absorption is most likely permanently impaired.

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Q10: Malabsorption & Malnutrition

Gastric hypersecretion Cholelithiasis Hyperoxaluria & Nephrolithiasis Diarrhea & Steatorrhea Intestinal Microflora

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Q10: Malabsorption & Malnutrition

Gastric hypersecretion – in early postop period. Increased acid load may injure distal bowel mucosa hypermotility & impaired absorption.

Cholelithiasis – altered bilirubin metabolism after ileal resection increased risk of pigmented gallstones stones that is 2nd to a decreased bile salt pool. TPN also may lead to increased risk of cholelithiasis.

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Q10: Malabsorption & Malnutrition

Hyperoxaluria & Nephrolithiasis – Excessive fatty acids within the colonic lumen

bind intraluminal calcium. Unbound oxalate that normally is made

insoluble by Ca-binding and is excreted in feces is thus, readily absorbed.

This results in hyperoxaluria and calcium oxalate urinary stone formation.

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Q10: Malabsorption & Malnutrition

Diarrhea & Steatorrhea – Caused by rapid intestinal transit.Presence of hyperosmolar enteric contents.Disruption of enterohepatic bile acid

circulation.Fat absorption is most severly impaired by

ileal resection.

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Q10: Malabsorption & Malnutrition

Intestinal Microflora – Loss of ileocecal valve permits reflux of

colonic bacteria into small bowel. Intestinal dysmotility increases colonization.Bacterial overgrowth & change in flora results

in pH alteration & deconjugation of bile salts.This results malabsorption, fluid loss,

decreased vit B12 absorption.

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Q11: Effect of ASA on Plt.

Irreversibly acetylates cyclooxygenase Results in inhibiting plt synthesis of

Thromboxane A2. Decreases plt function. Higher doses than > 80 – 160mg PO / day

donot have a higher efficacy.

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Q12: Synergism Ampicillin / Sulbactam (Unasyn)

PCN: GPC – streptoccocci, syphilis, GPR - Neisseria m., C. perfringens, Beta-hemolytic strep, antrax Not effective for Staph or Enterococcus

Ampicillin/amoxicillin: PCN + Enterococcus coverage Unasyn: PCN + GPC (staph & strep), GNR +/-

anaerobic coverage, enterococci. NOT FOR Pseudomonas, Acinetobacter, or Serratia. Sulbactam & Clavulanic acid – are beta-lactamase

inhibitors. Nir Hus