FINAL Flashcards
Cardiac Output using Ohm’s law
(MAP-CVP/SVR) x 80
Partial pressure of substance (outside body)
Patm x % of molecules
Partial pressure of inspired gas (PiO2)
% x (Patm-PH20) partial pressure of H20 is 47
Pressure of oxygen in alveoli (PAO2)
[FiO2 x (Patm - PH20)] - PaCO2/0.8
How do you calculate A-a gradient and what is the normal?
PAO2- PaO2 (5-15 mmHg)
Law of Laplace (sphere/alveoli)
P= 2T/R
Compliance
Delta V/Delta P or (TV/PIP-PEEP)
Boyle’s Law/Ideal gas law
PV=nRT (as pressure drops, volume increases)
Alveolar Ventilation
(TV-DV) x RR
How do you calculate dead space (DV)?
2 ml/kg of IBW or PaCO2-PeCO2/PaCO2 (take % and apply to TV)
Total O2 Content
(1.39 x Hgb x %sat) + 0.003 PO2
Dissolved CO2
PaCO2 x 0.067
IBW
Women 105 + 5 lbs for every in over 5’ Men 106 + 6 for every in over 5’
Calculating Stroke Volume
EDV-ESV
Calculating EF
(EDV-ESV)/EDV x 100
Calculating MAP
1) SBP-DBP 2) divide by 3 3) add that to diastolic
Pulse Pressure
SBP-DBP
Coronary Perfusion Pressure
DBP- LVEDP
What % of CO does the liver get?
25%
What are the functional units of the liver?
hepatic lobule or acinus
Normal hepatic blood flow
1500 mL/min
How much blood flow comes from the hepatic artery?
25-30%
How much blood flow comes from the portal vein?
70-75%
O2 sat of blood from portal vein
60-85%
How much oxygen does the hepatic artery supply?
45-50% of requirements
How much oxygen does the portal vein supply?
50-55% of requirements
Mean BP of hepatic artery
40-70
Mean BP of portal vein
5-10
Why is the dual supply to the liver important?
makes it resistant to hypoxia
Hepatic arterial flow is dependent on…
autoregulation
Portal vein flow is dependent on…
blood flow to GI tract and spleen
What happens to liver blood flow after meals?
increases
What vessels converge to form the hepatic portal vein?
superior mesenteric, inferior mesenteric, and splenic veins
Receptors in Hepatic artery vs portal vein
artery- alpha and beta vein- only alpha
Kupffer cells
remove bacteria and endotoxin entering the blood stream from the portal circulation- part of reticuloendothelial system
Metabolic functions of the liver
carbs, fats, proteins, drugs
Final products of carb digestion
glucose, fructose, galactose
Hepatic conversion of fructose and galactose into ? makes ? metabolism the final common pathway for most carbs
glucose
Cells use ? to produce ? either aerobically via the citric acid cycle or anaerobically via glycolysis
glucose; ATP
Anion gap
(Na+K)-(Cl+HCO3)
plasma osmolarity
2(Na+K)+0.055(glucose)+0.36(BUN)
Aortic root pressure
1/3(LVP-aortic root P)
Coronary perfusion pressure
DBP-CVP
Cerebral perfusion pressure
MAP-ICP or MAP-CVP
Filtration fraction
GFR/RBF
Glomerular filtration pressure
MAP-(colloidal P+glomerular P)
Glucose is stored in hepatocytes as ?
glycogen
gluconeogenesis
liver produces glucose from lactate, pyruvate and amino acids (maintains normal glucose)
What stimulates and what inhibits gluconeogensis?
stimulates- glucocorticoids, catecholamines, glucagon, thyroid hormones inhibits- insulin
Glycogenolysis
release of glucose back into circulation
What stimulates glycogenolysis?
surgical stress, SNS stimulation
Liver makes plasma proteins except?
immunoglobulins
What coagulation factors does the liver NOT make?
VIII, vWF
What is produced by the liver that is important in regards to succinylcholine?
pseudocholinesterase
The liver combines 2 ammonia with CO2 to produce?
urea- excreted by kidneys
What are excess carbs and proteins converted into?
fatty acids
Fatty acids are oxidized into…
acetyl CoA
Acetyl CoA is used…
in cirtic acid cycle to produce ATP
Where is Acetyl CoA stored?
liver and adipose tissue
Obstructive vs. parenchymal disorders of the liver
obstructive- affect biliary excretion parenchymal- generalized hepatocellular dysfunction
What liver test is considered a true test of function?
serum bilirubin- reflects liver’s ability to take up, proess, and secrete bilirubin
Normal serum bilirubin
less than 1.2-1.5 mg/dL
van den Bergh reaction
indirect positive- unconjugated bilirubin biphasic- both unconjugated/conjugated direct positive- conjugated
What does high unconjugated bilirubin mean?
hemoglobin is being broken down too fast or the liver can’t process it fast enough (neurotoxic –> encephalopathy)
What does high conjugated bilirubin mean?
bilirubin is backing up in the liver
normal albumin
3.5-5.3 g/dL
What does low albumin indicate?
liver disease, nephrotic syndrome- half life is 14 days, so values are normal in acute liver disease
Prothrombin time (PT)- what is it and normal range?
measures how long it takes for clot to form (activity of fibrinogen, prothrombin, and factors V, VII, X)- 10-14 seconds
Normal platelet count
150,000-450,000 mm3
What does a prolonged PT mean?
severe liver disease (unless Vit K deficiency is present)
Transaminases
enzymes released into circulation as result of hepatocellular injury/death (AST and ALT)
AST
associated with cell necrosis (liver, brain, heart tissues)
ALT
LIVER CELLS ONLY- indicate cell inflammation
Blood ammonia is cleared by the liver and converted into?
urea
Normal ammonia levels
47-65 mmol/L
What does an elevation in ammonia indicate?
disruption of urea synthesis, severe hepatocellular damage, can cause encephalopathy
What do inhalation agents do to hepatic blood flow?
DECREASE- halothane is the worst *(isoflurane is the least- causes arterial dilation that can actually increase hepatic BF)
What does regional anesthesia do to hepatic blood flow?
decrease by lowering arterial BP
What does general anesthesia do to hepatic blood flow?
decreases by lowering arterial BP and CO
Which nervous system enhances gastric fluid secretion and motility?
PNS