Topic 5: Splanchnic Flashcards
Thoracic Cavity contains what three cavities?
above diaphragm
a. left pleural cavity
b. right pleural cavity
c. mediastinal cavity (includes pericardial)
Abdominopelvic Cavity - contains what 2 cavities with what organs?
a. abdominal cavity- stomach, liver, spleen, GI, pancreas, kidneys…
b. pelvic cavity- last part of large int. and reproductive organs
Body cavities function?
protect organs and allow space for organ movement
like inflation of lungs or contraction of hear
Splanchnic circulation will refer to the vasculature w/in what?
vasculature w/in the abdominopelvic cavity prior to the iliac bifurcation with the exception of renal vessels.
Why are kidneys not considered part of the splanchnic system?
Due to positioning, function, independent autoregulation, and direct aortic and IVC drainage
Limitations of research of CPB and splanchnic circulation?
- Small sample size
- Difficulty in monitoring abdominal viscera and correlating to outcomes
- Conflicting data
- Controlling for other variables
Incidence of GI complication with CPB?
~ 4.1%
90% of nutrient absorption occurs here?
Small Intestine (20ft)
Duodenum- location and function?
first 10”, serves as “mixing bowl” for chyme and digestive enzymes from liver and pancreas
Jejunum- length, location and function?
approx 8’, primary site of chemical digestion and nutrient absorption
Ileum- location, length and function?
approx 12’, last section before large int. Large [] of lymphoid nodules to protect SI from bacteria in LI.
Stomach - function? leads to?
Stores and breaks down ingested food via acids and enzymes (chyme).
Release into small intestine controlled by pyloric sphincter
Large intestine - function? length?
5ft
•Small amount of nutrient absorption, primarily vitamins from bacterial byproducts, fluid, and bicarb resorption
•Compaction and storage of chyme into fecal matter
CPB results in an increase in intestinal blood flow due to what?
↓ Resistance
Intestinal BF during CPB seems to be independent of what two things?
MAP and dependent on Q
•Intestinal ↑BF independent of what 3 things?
T, pH, or pCO2 (autoregulation?)
Extensive use of vasoconstrictors during CPB does what to mesenteric perfusion?
exacerbates the risk of inadequate mesenteric perfusion
Cardiac surgery is associated with a relatively low incidence of GI complications but those complications cause a disproportionate level of what?
a vastly disproportionate level of mortality
Pancreas primary function?
Primary function is production of digestive enzymes and buffers (NaHCO3) to neutralize acidic chyme.
Pancreas arterial blood sources?
Several sources from splenic, hepatic, and sup. Mesenteric
Pancreas - exocrine or endocrine organ?
Primarily an exocrine (99%) organ, but endocrine function is vital
Delta cells produce what?
somatostatin/tropin to suppress insulin and glucagon release
ENDOCRINE
F cells produce what?
pancreatic polypeptide; inhibits gall bladder contraction and some regulation of enzyme production
ENDOCRINE - PANCREAS
Alpha cells produce?
glucagon
ENDOCRINE - PANCREAS
Beta cells produce?
insulin
ENDOCRINE - PANCREAS
Pancreas % of Endocrine? what?
(1%) Islets of Langerhans/ Pancreatic Islets
Pancrease % of Exocrine? what?
Acinar Cells comprise 99% of the pancreas
Amylase does what?
breaks down starch/carbs
EXOCRINE - PANCREAS
Lipase does what?
breaks down lipids
EXOCRINE - PANCREAS
Nuclease does what?
breaks down nucleic acids
EXOCRINE - PANCREAS
Proteolytic enzymes do what?
Proteases attack large proteins
Peptidases break small peptides into amino acids
EXOCRINE - PANCREAS
Acinar Cells (4 types)
- Amylase
- Lipase
- Nuclease
- Proteolytic enzymes
CPB and the pancreatic flow?
poor autoregulation during CPB
Elevated what is a common indicator for pancreatic injury?
[amylase]
did not correlate to negative post-op symptoms
Amylase compared to lipase
Amylase more sensitive,
Lipase more specific
How often does Pancreatitis occur on CPB in adults?
Infrequently (0.1-0.8%), but carries ↑ mortality
Risk factors of developing pancreatitis on CPB?
CPB time and hypotension secondary to low cardiac output syndrome
Mild pancreatitis carries what % mortality?
~~50%
Severe pancreatitis carries what % mortality?
67%-100%
Pancreatic injury incidence post-CPB in peds ?
Much higher incidence (4-8%)
Lab tests for pancreatitis in peds?
trypsinogen-2 and trypsin-2-α 1-antitrypsin
Spleen two main components?
Red pulp: big honking filter and storage
White pulp: lymphoid tissues
Post-splenectomy patients have a substantially greater risk of what?
infection and a 33% greater risk of future MIs
Largest visceral organ?
Liver
multifunctional as well, also serves as a large blood reservoir
Blood flow to liver supplied by? at what rate?
supplied by hepatic artery at 400cc/min and portal vein at 1000cc/min
Where does the liver drain into? Applied to perfusion cannula placement?
Drains to the IVC just below the diaphragm; use caution in placing venous cannula to avoid obstruction and portal HTN.
Liver Metabolic Regulation?
All blood leaving the absorptive sections of the GI tract flows into the liver via the hepatic portal vein.
This allows nutrients and toxins to be removed, stored, or allowed into the systemic circulation
Intrinsic regulation determines nutrient storage or release.
Three main things the liver does?
metabolic regulation, hematologic regulation and bile production
Hematologic regulation of liver? (4)
- Removal of damaged formed elements or pathogens via Kupfer cells
- Plasma protein synthesis
- Antibody, toxin, and hormone removal occur by various mechanisms
- Carboxylation of vit K dependent coagulation factors
Kupfer cells
Remove damaged formed elements or pathogens
IN LIVER
How much Bile is produced each day and by what?
Approx. 1L produced each day by liver
Bile function?
•Necessary for lipid digestion
Concentrated Bile leads to?
Over concentrated bile leads to “gall stones
Where is bile stored?
Stored in gall bladder and released upon lipid detection in the duodenum (cholecystokinin stimulates bile production and gallbladder contraction)
Hepatic blood flow does what during CPB?
increases slightly during CPB. Perfusion is ↑ with ↑Q
Hypothermia is primary factor in what with drugs?
decreased clearance of drugs
Although not all drugs illustrate ↓C
CPB and liver damage?
- No clear link exists that CPB has a direct negative impact on the liver.
- Valve procedures, transfusions, and prolonged CPB times may show hepatic markers of injury
when measuring Albumin what kind of test is it?
a hepatic function lab
a hepatic function lab
Albumin:
Fairly specific hepatocellular leakage enzymes hepatic tests? (4)
Serum glutamic and oxaloacetic transaminase (SGOT)
Aspartate aminotransferase (AST)
Serum Glutamic pyruvic transaminase (SGPT) Alanine aminotransferase (ALT)
Two types of Total Bilirubin test?
hepatic test
- Unconjugated (relatively water insoluble)
* Direct (water soluble)
Unconjugated
relatively water insoluble
Direct
water soluble
Alkaline phosphatase (ALP) is a hepatic test that measures what?
is specific to the liver’s biliary tree and represents biliary damage or cholestasis
drugs that help dilate splanchnic vessels during massive pressor administration for sepsis ?
Dopaminergic (Dopamine & Dobutamine)
(explain)???
Fenoldopam mesylate (Corlopam)
is a selective D₁ agonist with no β effects, therefore best choice for splanchnic perfusion
Unlike the brain or kidneys during CPB, there appears to be a ______ response to the splanchnic circulation.
muted autoregulatory
Do higher pressures aid in splanchnic perfusion?
Higher pressures do not seem to aid in splanchnic perfusion except to liver (overcome portal and IVC P).
Although there is a low incidence of splanchnic injury, the consequences are what?
carry high mortality rates
