GI Flashcards
functions of GI tract
- major role: convert ingested nutrients into simpler forms that can be transported from the tract’s lumen to the portal circulation and then used in metabolic processes
- plays vital role in detoxification and elimination of bacteria, viruses, chemical toxins, and rugs
ligament of treitz
anatomic division between upper and lower GI tracts (proximal to the ligament is the upper GI, distal to it is lower)
causes of upper GIB
SPEM -PUD -Stress related erosive syndrome -esophageal varices -mallory-weiss tear those are the important ones. others are: -esophagitis -neoplasm -aortoenteric fistula -angiodysplasia
lower GIB causes
- diverticulosis
- angiodysplasia hemorrhoids
- inflammatory bowel disease
- trauma
- infectious colitis
- radiation colitis
- ischemia
- aortoenteric fistula
patho of PUD
- PUD occurs after protective mechanisms cease to function (glycoprotein mucous barrier, adequate blood flow, bicarbonate secretion, prostaglandins and nitric oxide) and the gastroduodenal mucosa breaks down
- once the mucosa is penetrated, gastric secretions autodigest the layers of the stomach or duodenum, leading to injury of the mucosal and submucosal layers, leading to damaged blood vessels and hemorrhage
causes of PUD
- increase acid production and decreased mucosal blood flow causing ischemia and degeneration of the mucosal lining
- 2 main causes: H pylori and NSAIDs
PUD tx; surgical and post op care
surgical: -vagotomy -pyloroplasty -stress ulcer prophylaxis -gastric resection -bilroth I -bilroth II -patch hole -excise ulcer post op: -fluid/electrolytes for imbalances -adequate nutrition, TPN for ileus -tx wound infection -tx/monitor for peritonitis if anastamosis rupture -pain -lung infections
what is a mallory weiss tear
it is an UGIB. an acute, arterial tear in gastroesophageal mucosa, accounting for 10-15% of UGIBs
causes of mallory weiss
- excessive ETOH
- long term NSAID/ASA
- forceful retching
portal vein pressures (normal, when do varices develop, when do they rupture)
- norm:2-6 mm Hg
- varices: 10
- varices rupture: 12
tx of esophagago varices rupture
- establish airway and patient stabilization!
- gastric lavage
- pharm:
- somatostatin and octreotide
- vasopressin
- endoscopics
- endoscopic injection sclerotherapy
- endoscopic band ligation
- TIPS
- mechanical tamponade (sengstaken-blakemore, minnesoate, linton)
- portocaval shunt (surgical, last resort)
- mesocaval shunt (surgical, last resort)
- fluids for hemodynamic stability (crystalloids, colloids, blood and blood products)
possible complications of varice rupture
- hypovolemic shock
- gastric perforation
s/s of UGIB
- hypovolemic shock (hypotn, tachycardia, cool clammy skin, change in LOC, decreased UO, decreased gastric motility)
- hematemesis
- hematochezia
- melena
- abd discomfort
- hyperactive bowel sounds
- ST segment depression
- flattening of t wave
what is a consideration when assessing H/H for GIB pts?
H/H levels are poor indicators of the severity of blood loss if the bleeding is acute. it may take 24-72h for the redistribution of plasma from the extravascular place.
labs/tests for UGIB
- over/occult blood (guaiac testing)
- Hgb normal then down
- hct normal then down
- wbc up
- platelets up then down
- K down then up
- sodium down
- calcium normal or down
- bun/cr up
- ammonia possibly up
- glucose up
- lactate up
- PT/PTT up
- respiratory alkalosis
- metabolic alkalosis
- gastric aspirate possibly acidotic
- endoscopy
- barium study
endoscopy for UGIB
this is the choice for diagnosis, treatment, and prevention of UGIB.
-PT MUST BE HEMODYNAMICALLY STABLE FOR ENDOSCOPY
tx of UGIB
- gastric lavage (before endoscopy)
- colloids, crystalloids, blood, blood products (priority is restore adequate circulating volume to tx or prevent shock)
- antacids
- H2 blockers
- PPIs
- mucosal barrier enhancers
- sclerotherapy (morrhuate sodium)
- thermal therapy
- endoclipping
- o2 therapy
- large NG may be inserted
nurse role in UGIB surgery
- assist MD
- watch for complications: respiratory complications, fever, oozing
- position pt in L. lateral reverse trendelenburg to prevent respiratory complications
- monitor pt at all times
antacids for UGIB: how do they work and examples
- direct alkaline buffer to control the pH of the gastric mucosa
ex: aluminum hydroxide, calcium carbonate, magnesium hydroxide, and magnesium oxide
histamine antagonists (h2 blockers): how do they work and examples
- block parietal cells secretion of Hcl
ex: cimetidine, famotidine, nizatidine, ranitidine