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52 Cards in this Set
- Front
- Back
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in what order are the following nerve fibers susceptible to local anesthestic small myelinated(Ay & A delta) small non-myelinated (Aa & Ab), large mylelinated (C)
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Most small myleniated(Ay & A delta)
Large myleinated (Aa * Ab) Least (small non-myleniated (C) |
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increased lipid solubility of a local anesthestic results in what regarding penetration of the lipid membrane
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MORE rapid penetration
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what is the net result of increased lipid solubility with a local anesthetic
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DELAYED ONSET
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when mixing local anesthetics with additives what should be presumed about toxicity
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that it is additive
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with local anesthetics alkalinization may do what
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*speed the onset of the block
*provide a greater depth of block *increase the spread of epidural block |
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how does pH adjustment or alkalinzation make changes to a block
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it increases the percentage of drug existing in the neutral form which may rapidly diffuse across the neuronal membrane
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how do you alkalinize a block
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add 1 ml of sodium bicarb to 10 ml of local anesthetic
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when is alkalinization of particular value
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when it is used with local with pre-packaged epi as the pH of these is lower to extend the shelf life of the epi
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the addition of vasoconstrictors does what with a local
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decreases the rate of vascular absorption providing:
*a denser block *prolonging the duration |
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how does the use of a vasoconstrictor with a local provide a denser block
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*more drug reaches the site of action
*may act through a2 adrenergic receptors to produce analgesia |
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how does addition of a vasoconstricor with a local prolong the duration
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by decreased clearance of drug from site of injection
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when is addition of a vasoconstrictor with a local most effective
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with infiltration and peripheral nerve blocks with drugs of short to moderate duration
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what is the most common vasoconstrictor added to a local
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epi 1: 200,000 (5 mcg/ml)
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when should you AVOID the use of a vasoconstrictor with a local
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in sites which may experience vascular compromise
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what is the most common drug for a bier block
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lidocaine WITHOUT epi
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what is the amt and percent of solution used for an upper extremity bier block
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40-50 ml 0.5% solution
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what is the amt and percent of solution used for a lower extremity bier block
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50-100 ml 0.25% solution
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there is a potential for what complication if ester LA are used with bier blocks
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thrombophelebitis
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for peripheral nerve blocks drug choice is primarily determied by what
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duration of block
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with peripheral nerve blocks there is the most rapid onset with what drugs
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drugs with INTERMEDIATE potency
(lidocaine, mepivacaine) |
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with peripheral nerve blocks when appropriate addition of lidocaine has the most benefit when
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with drugs of shorter duration
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how are esters metabolized
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by hydrolysis of the ester bond by plasma cholinesterase
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which ester is metabolized the fastest
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CHOLORPROCAINE
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which ester is metabolized the slowest
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TETRACAINE
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how are amides metabolized
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by enzymatic degradation in the liver
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the metabolism of amides is dependent on what factors
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*hapatic extraction
*hepatic perfusion *hepatic metabolism *protein binding |
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how are the metabolites of amides excreted
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renally
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what is the initial step of metabolism for lidocaine
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oxidative dealkylation
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with lidocaine clearance is decreased when
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*hepatic dysfunction
*prescence of volatile anesthetics *PIH |
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absorption of local anesthetics is dependent on what
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*vascularity of injection site
*fat content of injection site *dose of local anesthetic *physicochemical properties of the drug *presence of a vasoconstrictor |
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what type of agents have a higher lipid solubility and protein binding resulting in less systemic absorption
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more potent agents
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when would presence of a vasoconstrictor have a greater efficacy
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with the less potent, less lipid soluable and shorter acting agents
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what is ICEBS
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*intercostal
*caudal *epidural *brachial plexus *subarachnoid |
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what are the uses for an interscalene block
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*shoulder
*upper extremity |
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what are the complications/side effects of an interscalene block
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*diaphramatic paresis
*recurrent laryngeal nerve block *epidural or subarachnoid block *intravascular injection *nerve injury |
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what are the uses for a supraclavicular block
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*elbow
*forearm *hand |
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what are the side effects/complications of a supraclavicular block
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*pneumothorax
*phrenic nerve block *intravascular injection *horners syndrome *nerve injury |
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what are the uses for a infraclavicular block
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*forearm
*hand *elbow (not reliably) |
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what are the side effects/complications of a infraclavicular block
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*pneumothorax
*intravascular injection *nerve injury |
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what is the most popular approach to brachial plexus d/t ease, reliability and safety
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axillary block
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what are the uses for an axillary block
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*forearm
*hand *elbow (not reliably) |
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what are the side effects/complications of an axillary block
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*intravascular injection
*nerve injury |
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what are the uses of a sciatic nerve block
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combined with psoas compartment block for anesthesia of the thigh and knee
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what are the side effects/complications of a sciatic nerve block
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(nerve injury)
*residual dyesthesias lasting up to several months *vascular injury *mininal sympathetic block |
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ankle block is useful for what procedures
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procedures on the foot not requiring a tourniquet to be located above the ankle
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what are the side effects/complications of an ankle block
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*can be uncomfortable d/t multiple injections
*nerve injury |
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what are the uses of a cervical plexus block
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blockade in distribution of c2-c4
*primary use is for carotid endarterectomy in an awake pt |
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what are the side effects/complications of a cervival plexus block
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*intravascular block
*phrenic nerve block *superior laryngeal nerve block *spread of local to epidural or subarachnoid space |
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what are the uses for airway blocks
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anesthesia of the airway in conjunction with topical anesthesia of the airway for awake fiberoptic intubation or bronchoscopy
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what are the side effects/complications of airway blocks
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*intravascular injection
*systemic absorption *loss of protective reflexes |
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what are the uses for a stellate ganglion block
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tx of sympathetic dystrophy of the upper extremity
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what are the side effects/complications of a stellate ganglion block
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*intravascular injection
*epidural or subarachnoid injection *block of recurrent laryngeal nerve *brachial plexus block |
