ch 21 Flashcards Preview

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Flashcards in ch 21 Deck (34)
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1
Q

acids and bases

A

acids are H+ donors

base is a proton acceptor

2
Q

BE

A

base excess less than 0 is metabolic acidosis
value greater than 0 is metabolic alkalosis

used in clinical practice to determine lactic acidosis and determine adequacy of intravascular volume resusciation

3
Q

pka

A

the strength of an acid

4
Q

bilateral carotid endarterectomies…

A

abolish the peripheral chemoreceptor response and these patients have no hypoxic ventilatory drive.

5
Q

peripheral chemoreceptors

A

located at the carotid arteries and surrounding the aortic arch. carotid bodies are principle and are sensitive to changes in pa02, pac02, ph and arterial perfusion pressure. most sensitive to pa02

6
Q

central chemoreceptors

A

in the medulla and respond to changes in cerebrospinal fluid ph. co2 goes up -chemoreceptors are activated- and alveolar ventilation increases. this works except for very very high or very very low pac02

7
Q

renal response compensation during acidosis

A
  1. reabsorption of the filtered HC03
  2. excretion of titratable acids
  3. formation of ammonia.
8
Q

sampling delay

A

can lead to oxygen consumption and carbon dioxide generation by the metabolically active white blood cells.

9
Q

oxygenation

A

p02 decreases 6% for every 1C degree

p02 increases 6% for every 1C degree

10
Q

rapid c02 increase

A

myocardial dysfunction then metabolic acidosis leading to confusion and loss of consciousness. due to the abrupt decrease in ph.

chronic increases are well tolerated

11
Q

causes of respiratory alkalosis

A
increased minute ventilation (tvxbpm)
hypoxia- high altitude low fi02 severe anemia
iatrogenic (mechanical ventilation)
anxiety and pain
cos disease (tumor infection trauma)
fever, sepsis
drugs (salicylate, progesterone, doxapram)
liver disease
pregnancy
restrictive lung disease
pulmonary embolism
12
Q

causes of respiratory acidosis

A
increased c02 production
    malignant hyperthermia
    hyperthyroidism
    sepsis
    overfeeding
decreased co2 elimination
    pna, ards, fibrosis, edema
    laryngospasm, foreign body, ova
    lower airway obstruction asthma and cold
    chest wall restriction-obesity scoliosis, burns
     cns depression- anesthetics opioids cis legions
    decreased skeletal muscle strength
increase co2 rebreathing or absorption
    exhausted soda lima
    incompetent one way valve in breathing circuit
    laparoscopic surgery
13
Q

anion gap

A

(CL+hc03) - Na

normal gap is 8-12

14
Q

three main regulatory molecules control coagulation and facilitate the termination of the coagulation cascade

A

antithrombin
tissue factor pathway inhibitor
activated protein C

15
Q

patient with less than what percent or what value are more likely to have uncontrolled intraoperative bleeding

A

20-30% or less than 50,000

16
Q

hemophilia A & B

A

most common recessive inherited deficiencies.
A is deficiency in factor VIII
B is deficiency in factor IX
Prolonged PTT, normal platelet count and pt

17
Q

hemophilia C or rosenthal disease

A

autosomal recessive disorder that can be associated with bleeding and is characterized by a prolonged ptt

thorough preoperative evaluation plus consult with hematologist is necessary to manage preoperative care.

18
Q

factor XII deficiency

A

a prolonged putt and is associated with clotting rather than bleeding .

19
Q

Factor XIII

A

stabilizing the fibrin clot, delayed bleeding after hemostasis, impaired wound healing, and pregnancy loss

20
Q

von willebrand disease

A

most common inherited bleeding disorder. 1% of the general population. multiple binding sites for both platelet receptors and sub endothelial structures.

ddavp- treatment of choice for type 1.
DDAVP contraindicated in type 2b
ddavp- type 3 do not respond to this treatment- they need factor VIII and vWF concentrates

21
Q

vitamin K deficiency

A

fat soluble vitamin that is required for carboxylation of factors II, VII, IX, and X and proteins C&S.
(leafy greens)
patients with poor dietary intake, TPN, ileus or obstruction, newborns, oral antibiotic therapy are susceptible to vitamin k deficiency

22
Q

liver disease

A

clotting factors (except factor VIII are synthesized in the liver.

23
Q

what should not be used with hemophilia B

A

cryoprecipitate

24
Q

protein c protein s

A

protein c can be acquired secondary to underlying disease. seen with liver disease, severe infection, septic shock, and dic.
protein s associated with pregnancy, oral contraceptives, dic hiv, nephrotic syndrome and liver disease.

25
Q

DIC

A

caused most commonly from sepsis
widespread systemic activation of coagulation. leads to end organ dysfunction and multi organ failure.
consumption of of circulating coagulation factors platelets and fibrinogen results in life threatening bleeding.

thrombocytopenia
elevated fibrin degradation products (d dimer)
prolonged pt and ptt
low fibrinogen

26
Q

TXA-

A

in patients with active bleeding and suspected fibrinolysis antifibrolinitcs are administered.

27
Q

ACT

A

used for heparin monitoring in CABG patients. ACT must be greater than 400 to start bypass.

28
Q

plavix

A

noncompetitive irreversible antagonist. increased variability among population.

ticagrelor has much lower inter individual variability.

29
Q

warfarin

A

disrupts the formation of factor II, VII, IX and X and proteins C&S
40hr half life.

early reductions in the anticoagulant protein c causes hyper coagulable state.

30
Q

heparin

A

main complication of heparin is HIT. mortality rate of HIT is 30-40% suspect if platelets fall less than 100,000 or less than 50% baseline 5-10 days after initiation of heparin …if patient previously hit positive for cabg, titers to heparin should be preformed if timing allows.

31
Q

low molecular weight heparin

A

inhibit factor Xa
do not affect the ptt
assess by factor Xa levels
longer half lives- give one or twice daily
protamine is only partially effective in reversing lmwh
protamine not effective for fondaparinux
lmwh contraindicated for HIT+

32
Q

bivalirudin (angiomax)

A

shortest half life and is the drug of choice for renal and hepatic dysfunction.
(argatroban (a DTI) will prolong the inr the most which can complicate transition to warfarin)

33
Q

ventilatory response vs renal response

A

ventilatory response occurs in minutes renal response can slowly provide nearly complete restoration of the pH but it can take days.

34
Q

bicarbonate buffer system

A

co2 combines with water- makes carbonic acid- hydrogen and bicarb.