LOCAL ANESTHETICS PART II Flashcards
EFFECTIVENESS OF LOCAL ANESTHETICS depends on (2) factors:
Onset Time
Duration of Action
induction time
A. Onset Time
B. Duration of Action
A
time it takes to achieve a nerve block from deposition of the anesthetic
A. Onset Time
B. Duration of Action
A
the amount of time the nerve block will remain
A. Onset Time
B. Duration of Action
B
FACTORS AFFECTING THE EFFECTIVENESS OF LOCAL ANESTHETICS (10)
- pH OF SOLUTION
- pH OF TISSUES WHERE ANESTHETIC IS DEPOSITED
- pKa OF SOLUTION
- LIPID SOLUBILITY & CHON BINDING CHARACTERISTICS
- TYPE AND SIZE OF NERVE
- ARRANGEMENT OF NERVE FIBERS IN THE COAXIAL BUNDLE
- INJECTING INTO A HIGHLY VASCULAR AREA
- PRESENCE OF VASOCONSTRICTOR
- VASODILATOR ACTIVITY
- NON-NERVOUS TISSUE DIFFUSIBILITY
T/F
increased pH means alkalinization and faster onset time
T
T/F
decreased pH means acidification and slower onset time
T
pH without vasoconstrictor
A. 5.5
B. 3.3
A
pH with vasoconstrictor
A. 5.5
B. 3.3
B
acidification of tissues causes inadequate anesthesia
A. pH OF SOLUTION
B. pH OF TISSUES WHERE ANESTHETIC IS DEPOSITED
C. pKa OF SOLUTION
D. LIPID SOLUBILITY & CHON BINDING CHARACTERISTICS
E. TYPE AND SIZE OF NERVE
F. ARRANGEMENT OF NERVE FIBERS IN THE COAXIAL BUNDLE
G. INJECTING INTO A HIGHLY VASCULAR AREA
H. PRESENCE OF VASOCONSTRICTOR
I. VASODILATOR ACTIVITY
J. NON-NERVOUS TISSUE DIFFUSIBILITY
B
deprotonation will not occur if the pH is acidic
A. pH OF SOLUTION
B. pH OF TISSUES WHERE ANESTHETIC IS DEPOSITED
C. pKa OF SOLUTION
D. LIPID SOLUBILITY & CHON BINDING CHARACTERISTICS
E. TYPE AND SIZE OF NERVE
F. ARRANGEMENT OF NERVE FIBERS IN THE COAXIAL BUNDLE
G. INJECTING INTO A HIGHLY VASCULAR AREA
H. PRESENCE OF VASOCONSTRICTOR
I. VASODILATOR ACTIVITY
J. NON-NERVOUS TISSUE DIFFUSIBILITY
B
low pKa means higher concentration of RN causing faster diffusion through the nerve membrane and producing a rapid onset time
A. pH OF SOLUTION
B. pH OF TISSUES WHERE ANESTHETIC IS DEPOSITED
C. pKa OF SOLUTION
D. LIPID SOLUBILITY & CHON BINDING CHARACTERISTICS
E. TYPE AND SIZE OF NERVE
F. ARRANGEMENT OF NERVE FIBERS IN THE COAXIAL BUNDLE
G. INJECTING INTO A HIGHLY VASCULAR AREA
H. PRESENCE OF VASOCONSTRICTOR
I. VASODILATOR ACTIVITY
J. NON-NERVOUS TISSUE DIFFUSIBILITY
C
pKa affects the onset time of the local anesthetic
A. pH OF SOLUTION
B. pH OF TISSUES WHERE ANESTHETIC IS DEPOSITED
C. pKa OF SOLUTION
D. LIPID SOLUBILITY & CHON BINDING CHARACTERISTICS
E. TYPE AND SIZE OF NERVE
F. ARRANGEMENT OF NERVE FIBERS IN THE COAXIAL BUNDLE
G. INJECTING INTO A HIGHLY VASCULAR AREA
H. PRESENCE OF VASOCONSTRICTOR
I. VASODILATOR ACTIVITY
J. NON-NERVOUS TISSUE DIFFUSIBILITY
C
Lidocaine pKa
7.7
Percent base (RN) at pH 7.4 of lidocaine
29
Onset of time of lidocaine
2 to 4 min