LA Final Review 11-29-23 PDF

11/8/23 COMPLICATIONS TO LOCAL ANESTHESIA What are the most common acute and chronic complications of Local Anesthesia? o Acute = post-injection pain o Chronic = trismus Needle breakage: o Most common nerve block involved in needle breakag...

11/8/23 COMPLICATIONS TO LOCAL ANESTHESIA What are the most common acute and chronic complications of Local Anesthesia? o Acute = post-injection pain o Chronic = trismus Needle breakage: o Most common nerve block involved in needle breakage ▪ IANB o Most common needle size ▪ 30G o Multiple causes ▪ Bending needle at the hub ▪ Unexpected patient movement ▪ Forceful contact with bone o How to prevent ▪ No short needles for IANB ▪ No 30 gauge ▪ Do not bend ▪ Do not hub ▪ Do not flex needle forcefully against bone Paresthesia: o Definition ▪ Abnormal sensation = feeling numb or tingly days after injection o Causes ▪ Nerve trauma ▪ Neurotoxicity from alcohol or sterilizing solutions in the tissues ▪ Hemorrhage compressing the nerve ▪ High concentration LA solution (4%) seen with articaine and prilocaine o How long does it take to resolve ▪ 8 weeks Trismus o Definition ▪ Muscle spasms of the jaw muscles preventing complete mouth opening o Symptoms ▪ Pain and limited opening day after administration of IANB or PSA NB. o Acute and chronic causes ▪ Acute causes ▪ Hemorrhage or trauma ▪ Chronically (>1 day) ▪ Fibrosis or scar tissue formation  o How to avoid trismus? ▪ Use sharp needles ▪ Use asceptic technique ▪ Use atraumatic technique ▪ Avoid repeat injections in the same area o Treatment ▪ If cause is NOT HEMORRHAGE ▪ Heat, warm saline rinses, analgesics/anti-inflamatories (20 min every hour) ▪ Warm saline hold in affected area ▪ Physical therapy ▪ Open and close mouth/lateral movements (5 min every 3-4hrs) ▪ Gum chewing ▪ If cause is Hemorrhage ▪ NO HEAT FOR 4-6 HRS ▪ AFTER 4-6HRS ▪ Heat, warm saline rinses, analgesics/anti-inflamatories (20 min every hour) ▪ Warm saline hold in affected area ▪ Physical therapy ▪ Open and close mouth/lateral movements (5 min every 3-4hrs) ▪ Gum chewing ▪ Improvement ▪ 48-72 hours expected IMPROVEMENT ▪ If pain after 48hrs add antibiotic for 7 days ▪ Expected COMPLETE recovery on average 6 weeks ▪ 4 week min ▪ 20 week max ▪ If no relief >20 wks = refer to OMFS/OFP Hematomas o Block associated with (intraoral/extraoral) hematomas ▪ Visible intraorally = IANB ▪ Visible extraorally = PSA o Management ▪ Immediate hematoma ▪ Apply pressure for more than 2 min ▪ Do not apply heat for 4-6 hours ▪ After 6 hours hot compresses for >20 min/hour  Pain on injection o Most common causes ▪ Quick needle advancement ▪ Quick LA deposition ▪ Dull needle (from multiple use) ▪ Barbs in needle (from multiple use) o Prevention ▪ Introduce needle/local anesthetic slowly ▪ Use sharp needle ▪ Use sterile solutions ▪ Use buffered solutions (if you can afford it) Post anesthetic lesions o when do they happen ▪ 2 days after injection o underlying causes ▪ trauma triggers ulcers due to: ▪ recurrent apthous stomatitis ▪ herpes simplex o how long do they last ▪ may last 7-10 days 11/8/23 N2O SEDATION Know N2O/O2 cylinder: color, psi, liters o N2O ▪ Blue, 750psi, 1600L = N2O ▪ Green, 2000psi, 625L = OXYGEN Know mechanism of action for N2O / which mechanism causes sedation, which causes analgesia? o Sedation through NMDA antagonism o Analgesia through kappa opioid stimulation through release of endogenous opioids that bind to kappa receptors Know N2O tank behavior (when will psi needle drop and how much N2O is left) o N2O is 95% liquid and psi will read 750psi until 20% is left, then needle will drop a lot ▪ Only way to truly know amount of N2O left is to weigh the tank Know N2O blood solubility and what it means o Low blood solubility = fast onset and offset (N2O can’t wait to get into tissues and out of the lungs) Know where is N2O metabolized/eliminated and how much o Trivial body metabolism o 99% eliminated in the lungs o 0.004% eliminated by bacteria in GI Know PISS and DISS and what these mechanisms are used for o Pin Index System = prevents the wrong tank from attaching to the wrong regulator by the use of pins o Diameter Index System = uses the diameter of attachments to prevent the wrong hose from attaching to the wrong gas inlet (you do not want N2O going into the oxygen supply or vice versa) Know the importance of a distended reservoir bag, scavenging system o Distended reservoir bags: ▪ visual cue that pt is breathing (bag will get smaller and larger as pt breathes in and out) ▪ provides you with reserve oxygen you can give your pt if they need it in emergencies ▪ visual cue that you have a good seal in your system ▪ if you don’t have a seal the bag will be flat (not inflated) o scavenging system ▪ suctions excess N2O to prevent room contamination of N2O  Know the characteristics of N2O: solubility, potency, analgesia, sedation properties. o Insoluble in blood o Lacks potency o Weak analgesic o Weak sedative Know the effect of N2O on: the cardiovascular system, respiratory system, homeostasis, blood glucose o Cardiovascular ▪ Minimal effect to none (it doesn’t affect the heart) o Respiratory ▪ Minimal to none (it doesn’t affect breathing) o Homeostasis ▪ Minimal to none (it doesn’t affect homeostasis at all) o Blood glucose (endocrine) ▪ Minimal to none (it doesn’t affect the endocrine system at all) Know the titration sequence: how do you start, how many liters you use in the middle, how do you stop the case o 1) pt breathes 6L/min of 100% O2 for 5 min o 2) then 5 L/min of O2 with 1L/min of N2O o 3) then titrate by 0.5L ▪ Go down on oxygen by 0.5 / go up on N2O by 0.5 o 4) until you are at 50% O2 and 50% N2O (this is your max in LLU) o 5) Don’t go higher than this or you’ll start seeing unwanted effects o 6) When procedure is over, turn off N2O and give pt 5L/min of O2 for 5min ▪ Do this to prevent diffusion hypoxia Know absolute and relative contraindications for N2O o Absolute ▪ Inability to use a nasal mask ▪ Inner ear infection or recent inner ear surgery ▪ Pneumothorax ▪ Patient refusal ▪ No consent? No treatment o Relative ▪ Psychiatric disorders (particularly in patients on psychotropic medications) ▪ Disinhibition ▪ Drug abuse ▪ Identifying patients seeking the euphoria ▪ COPD (severe) ▪ Pregnancy ▪ Bowel Obstruction (due to the ability of nitrous oxide to expand in gas-containing spaces)  Know what causes diffusion hypoxia/why/how to treat it o After discontinuation of N2O, N2O rapidly moves from tissue and blood into alveoli = decreases concentration of O2 in the lungs (higher conc of N2O than O2) = low O2 is called hypoxia o Give pt 100% O2 5 L/min for 5 min to prevent diffusion hypoxia Flow meter measurement/measured at the middle of the floating ball not the top or the bottom o Just know this. Is not the bottom or the top of the ball is the middle Know that while administering N2O if pt is not feeling well the correct course of action is to lower nitrous oxide levels to previous dose that was not giving the patient problems o For example: If the patient is experiencing problems with O2 at 3L and N2O at 2L = increase O2 to 3.5L and decrease N2O to 1.5L Know the symptoms for desired vs undesired levels of sedation for nitrous oxide o Desirable ▪ Conscious and muscles-relaxed ▪ Feeling of well-being, euphoria ▪ Stable vitals ▪ Reports of tingling in toes and fingertips, lips, tongue ▪ Warm sensation ▪ Voice changes due to effects on tympanic membrane ▪ Pain control ▪ Heaviness in lower extremities or floating feelings ▪ Sensation of flying, falling, or spinning (may be too deep) o Undesirable ▪ Laugh, cries, giddy (disinhibited) ▪ Uncooperative, restless, and agitated ▪ Becomes uncomfortable ▪ Falls asleep, jerks, mouth repeatedly closes ▪ Irrational responses ▪ Talks incoherently, mentions dream (usually inappropriate content) ▪ Complains of nausea ▪ Vomiting ▪ Non-responsive, unconscious Know which level of N2O sedation is the maximum appropriate level which will treat 95% of our population o 50% or less 11/15/23 PHYSICAL EVALUATION Know the mechanism of action of Epinephrine o a1 stimulation = increase blood pressure o B1 stimulation = increased heart rate o B2 stimulation = bronchodilation ASA Categories o ASA category definitions ▪ ASA I = healthy ▪ ASA II = mild/controlled disease ▪ ASA III = moderate or uncontrolled disease ▪ ASA IV = severe disease / constant threat to life ▪ ASA V = dying ▪ ASA VI = brain-dead o Which ASA category requires medical consultation/treatment modification ▪ III ▪ Conditions needing a medical clearance ▪ Patient that has not seen a physician in the last year (unknown ASA status) ▪ Pregnancy ▪ Concerning symptoms: ankle swelling, SOB, irregular HR ▪ Uncontrolled: HR / BP ( >180/110) but asymptomatic / liver, kidney function not controlled ▪ Recent surgeries 6 months ▪ Stable angina ▪ CHF w ankle edema ▪ COPD: Emphysema, Chronic bronchitis ▪ Poorly controlled asthma (every week) ▪ Frequent seizures (several times a week/day) ▪ Diabetics: controlled type 1 / uncontrolled type 2 ▪ Chronic kidney disease / scheduled dialysis o Which ASA category is contraindicated for elective dental surgery ▪ IV ▪ Conditions fitting this category ▪ MI / CVA 180/110 BP WITH SYMPTOMS  Know the minimum amount of time after MI/CVA before patient can receive dental treatment and why o 6 months / because within those 6 months there is a higher risk of repeat attack Drugs putting patients at risk for increased blood pressure with vasoconstrictor (from LA) infiltration into the blood stream o Propranolol ▪ Why is this drug a problem for HTN ▪ Block B receptors but NOT alpha receptors ▪ Higher risk of hypertensive episode due to unopposed a- vasoconstriction (that comes from your LA) with bradycardia o Cocaine ▪ Know the risks of pt cocaine use ▪ Increases HR, BP, Arrhythmias ▪ Incr risk of stroke, MI, hypertensive crisis ▪ Know the mechanism of action of cocaine ▪ Indirect acting adrenergic stimulant = makes the body release its own epinephrine/norepinephrine stores ▪ Know waiting period before treatment for patients using or abusing cocaine ▪ No tx for 24hrs o Methamphetamine (like cocaine) o TCA (any drug ending in “tryptyline”) 11/15/23 EMERGENCIES IN THE DENTAL OFFICE Know each part of the Emergency Protocol (P-CAB-D) o P – Position o C – Circulation o A – Airway o B – Breathing o D – Drugs/Defibrillate What is the most common dental emergency encountered? o Syncope What are the most common causes of Syncope? o Noncardiac – anxiety/fear, pain, vasovagal (overreaction of parasympathetic) What are the signs and symptoms of syncope? o Unresponsive, limp, pale ashen-grey, hypotension, bradycardia, sweaty, nausea, convulsive/twitching. How quickly do non-fatal syncope/noncardiac patients respond to repositioning? o Pt respond within a minute (respond quickly) Know the actions and use of Benzodiazepines o Used for: ▪ Sedation ▪ Anxiety ▪ Antiseizures (because they sedate the brain) o GABA agonist = GABA activation calms (hyperpolarization) the brain o NO EFFECT ON BP OR HR!!! ▪ On their own, benzos will not drop or increase your HR or BP unless combined with other drugs Know in which instances convulsions would warrant transport to the ER o Sz lasting >2min o No previous sz hx o One seizure after another (continuous) o Injury then seizure Know the definition of hypoglycemia in mg/dl o 90mmHg systolic = ok to give nitro /