Phosphates and Lactate (FSKP) Flashcards

0
Q

% phosphate in bone, in soft tissues and in serum/plasma (active form)

A

80% in bone, 20% in soft tissues, <1% in serum/plasma

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1
Q

Predominant intracellular anion

A

Phosphate

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2
Q

Concentration of phosphate in blood

A

12 mg/dL (3.9 mmol/L)

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3
Q

Concentration of inorganic phosphates in blood

A

3-4 mg/dL

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4
Q

complex phosphodiesters

A

DNA and RNA

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5
Q

Coenzymes of phosphates

A

Esters of phosphoric or pyrophosphoric acid

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6
Q

Reservoirs of energy (phosphate)

A

ATP, creatine phosphate and phosphoenolpyruvate

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7
Q

Facilitates release of O2

A

2,3-biphosphoglycerate (2,3-BPG) in RBcs

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8
Q

-Acts to increase Phosphate in the blood

A

Vitamin D (increased)

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9
Q

-Increases both phosphate absorption in the intestine and phosphate reabsorption in the kidney

A

Vitamin D (increased)

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10
Q

In excessive secretion or administration of this, phosphate in the blood may increase because of decreased renal excretion

A

Growth hormone (increased)

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11
Q

Decreases phosphate by inhibiting reabsorption

A

PTH and calcitonin

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12
Q

60-80% of patients in ICU with hypophosphatemia has

A

Sepsis

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13
Q

Causes of hypophosphatemia

A
  • increased renal excretion
  • hyperparathyroidism
  • decreased intestinal absorption, as w/ vit. D deficiency or antacid use
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14
Q

Mortality rate of mild hypophosphatemia

A

15%

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15
Q

Mortality rate of severe hypophosphatemia

A

<1.0 g/dL or 0.3 mmol/L

30%

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16
Q

Causes of hyperphosphatemia

A
  • increased intake of phosphate (neonates)
  • increased breakdown of cells
  • lymphoblastic leukemia
17
Q

Specimen for determination of inorganic phosphate

A

Serum or Li heparin plasma, urine (24hr)

18
Q

Sources of error of inorganic phosphate

A
  • oxalate, citrate, or EDTA: interfere
  • hemolysis: high conc. inside RBCs
  • Circadian rhythm: highest in late morning and lowest in the evening
19
Q

Methods (phosphate)

A

Colorimetry

1. Fiske Subbarow
2. Gomori Modification
20
Q

Formation of an ammonium phosphomolybdate complex (colorless)

A

Colorimetry

21
Q

Colorimetry is read by

A

UV absorption at 340 nm or reduced to form molybdenum blue read at 500-700 nm

22
Q

Specimen of this method is precipitated with TCA

A

Fiske Subbarow

23
Q

This method uses Molybdenum reagent to form heteromolybdenum complex or phosphomolybdate complex

A

Gomori Modification

24
Reference range of serum/plasma for phosphate in neonates
1.45-2.91 mmol/L (4.5-9.0 mg/dL)
25
Reference range of serum/plasma for phosphate in child
1.45-1.78 mmol/L (4.5-5.5 mg/dL)
26
Reference range of serum/plasma for phosphate in adults
0.87-1.45 mmol/L (2.7-4.5 mg/dL)
27
Reference range of 24 hr urine for phosphate
13-42 mmol/day (0.4-1.3 g/day)
28
By-product of an emergency mechanism producing a small amount of ATP when O2 delivery is severely diminished
Lactate
29
The normal end product of glucose metabolism (glycolysis)
Pyruvate
30
Conversion of pyruvate to lactate is activated when
A deficiency of oxygen leads to an accumulation of excess NADH
31
Associated with hypoxic conditions (shock, myocardial infarction, severe blood loss)
Type A lactic acidosis
32
Metabolic origin (diabetes mellitus, severe infection, leukemia, liver or renal disease, and toxins [ethanol, methanol, salicylate poisoning])
Type B lactic acidosis
33
Specimen for determination of lactate
- tourniquet should not be used: venous stasis will increase lactate levels - do not exercise the hand - anaerobic glycolysis should be prevented - heparinized blood may be used: must be delivered on ice and plasma must be quickly separated - use iodoacetate or fluoride to inhibit glycolysis w/o affecting coag
34
Methods (lactate)
``` Monitoring oxygenation Enzymatic method (coupled) ```
35
Enzymatic method (coupled)
Lactae + oxygen (acted by the enzyme: lactate oxidase)----> pyruvate + hydrogen peroxide (H2O2) Hydogen peroxide + H donor + chromogen (acted by the enzyme: peroxidase) ----> colored dye + 2 water (H2O)
36
Reference Range of lactate (venous)
0.5-2.2 mmol/L (4.5-19.8 mg/dL)
37
Reference range of lactate (arterial)
0.5-1.6 mmol/L (4.5-14.4 mg/dL)
38
Reference range of lactate (CSF)
1.1-2.4 mmol/L (10-22 mg/dL)
39
Monitoring oxygenation
- in dwelling catethers that measure blood flow - pulse oximeters - base-excess determination - measurements of oxygen consumption (VO2)