W5 LA Flashcards
What are 6 reasons for LA failure?
- Inadequate dose.
- Acute inflammation: low tissue pH affects onset of action of LA.
- Injection into blood vessles.
- Inadequate patience
- Incorrect technique/unusual anatomy
- Expired LA or not stored adequately
Describe the volume of solution for the pterygomandibular space
Volume approx 3.6mls. By ↑ volume of lignocaine in asymptomatic teeth this does not result in faster onset.
However if patient who have symptoms of pulpitis ↑ vol helps.
What is the safest LA?
Lignocaine!
What are the causes of pain of injection?
Careless technique. Too rapid injection. Subperiosteal injection (if bevel is not facing bone). Sol too cold or hot. Unintentional pricks, electric shock n.
How do you prevent pain of injection?
Know your landmarks. Good technique. Inject slowley Bevel facing bone. Make sure LA is at room temp when injecting.
What are 2 sensitivity disorders?
Prolonged anaesthesia
Paraesthesia
How do sensitivity disorders manifest clinically?
Burning or tingling.
Persistent anaesthesia
Define paraesthesia
Tinging or pins and needles
Define Hyperesthsia
Increased sensitivity to noxious stimuli
Define dysesthesia
Pain to non-noxious stimuli
Physiologocally what causes nerve trauma?
Trauma to n. impairs n. conduction by needle or indirect.
Administration of LA from a cartridge contaminated with alcohol = irritation → odema.
Risk of n. damage is ↑ if repeat injections are given.
How do you prevent paraesthesia?
Adhere to injection protocol
How do you manage sensitivity disorders?
Speak to pt personally, advise it is not uncommon.
Transient will last 8 weeks (do not tell pt).
Document.
* if unresolved in 8 weeks may be irriversable
What are the causes of needle breakage?
Needle may have been bent first, and inserted to its entire length.
+ Sudden movement
How do you prevent needle breakage?
Larger gauge needles.
Do no insert all the way into hub.
Do not apply extensive lateral pressure whilst needle is inserted.
How do you manage needle breakage?
Remain calm, ask pt to remain still.
If you can see needle remove it. If not, document event and refer to maxiofacial surgeon.
Document!
What is a needle track infection?
If you inject into an area of inflammation or abscess you are at risk of introducing infection to surround healthy tissues.
Explain direct impact of needle track infection
Needle is contaminated when it perforates infected area, this needle is used to deposit sol into deeper and healthy needles.
Explain indirect impact of needle track infection
If LA deposited under pressure the for of administration might transport bacteria into healthy adjacent tissues.
Define trismus
Prolonged spasm of jaw muscles which impairs normal opening (muscles of mastication)
What is the cause of trismus?
IAN into medial pterygoid m.
Haemorrhage.
Bleeding into muscle following injection. May cause myotoxic response - necrosis
How do you prevent trismus?
Adhere to injection protocol.
Avoid repeat injections
Usee minimum effective vol of LA.
What is the management of Trismus
Mild:
Interum - heat, saline rinse, analgesic. Dentist to prescribe muscle relaxant (ab in necessary).
Document
How long would it take for trismus to disappear?
7-10 days
If trismus is prolonged who do you refer to?
Maxofacial surgeon
What is the cause of facial n. paralysis?
Introduction of LA into capsule of parotid gland, results in unilateral paralysis of muscles of facial xpression.
(By not touching the bone, bypassing the ramus into parotid capsule).
Itraogenic
How do you prevent facial n, paralysis?
Adhere to injection protocol, elsure touching bone is felt prior to deposition of LA
What are the causes of soft tissue injury?
Frequent lip biting, tongue or cheek.
How do you present soft tissue injury?
Select LA appropriate for pt.
Cotton role in mouth.
Post OP instructions
DOCUMENT.
What is the management soft tissue injuries?
Analgesics, saline mouth rinse, vaseline. If severe lacerations due to systemic involvement may need ab by dentist.
What is the cause of haematoma?
Effusion of blood into extravascular space, most likely by accidently nicking a blood vessel.
(pterygoid plxus, PSA vessels, IAV vessels, mental vessels, can occur in pterygoidmandibular space)
How do you prevent haematoma?
Good knowledge of anatomy
how do you manage haematoma?
Apply direct pressure until bleeding stops.
Adivsee pt of soreness.
Apply ice (vasoconstricor) intermittently for first- hours (no heat).
How long can haematoma last?
7-14 days
What are causes of membrane lesions?
Prolonged ischemia of tissus as a direct result of vasoconstrictor, or reaction on mucous tissues to anaesthetic agent.
How do you prevent mucous membrane lesions?
Only use topical for 1-2min, try not to useoverly concentrated vasoconstrictiors (ligno, articain)
How do you manage if a patient presents with mucous membrane lesions?
Reassure patient, analgesics if required, saline mourth rinse, ointment
What are other intraloral lesions?
Pts may report a couple of days after LA that ulcerations have dveloped, around injection.
Cause
What are some causes of intraoral lesions?
Recurrent apthous stomatitis
Herpes.
How do you manage intraoral lesions?
Manage pain, assure pt not bacterial but exacerbation, refer to dentist for script
What are the symptoms of psychogenic ?
Syncope, panic attack, nausea, vomiting
What is the cause of psychogenics?
Emotional disturbances stress and dear.
- May lead to vaso-vagal response or effects of myocardial depression and vasodilation).
How do you manage psychogenics?
If syncope, lay down and elevate legs.
Alert pt via sound and pain.
Calm the patient
Define hypersensitivity reaction
Exaggerated response of patients immune system.
What LA group can trigger an exaggerated response?
Esters: sensitivity to their metabolite, paraaminobenzoic acid.
Amides are used as alternatives in those pts.
What systemic reactions can occur due to hypersensitivity?
Skin: itching, flushing, hives, oedema
GIT: cramps, nausea, vomiting, incontinence
Reespiratory: shortness of breath, cynosis
CVS: palpitations
What is the managment of allergies?
Mild:
Ceas dx
Remove allergn
Give oral antihistamine.
→ if hypotension and evidence of anaphylaxis: cease dx. Remove allergen.
000, epipen, monitor vital signs, basic life support.
What can cause toxisity?
Can be caused by sol. & vasoconstrictor.
What are factors that impact risk of toxicity?
Pt age and weight. Medications Does Site of injection Compromisd pt.
What tissues may be excited by LA?
CVS
CNS
What are symptoms in the CNS system?
Stimulation/pre-convulsive phase.
Warning signs, restlessness, tremor, confusion or agitation
++ Respiratory depression
What are CVS complications
Increased LA can cause myocardial depression , then cardiac arrest.
Increased adrenaline causes vasoconstriction of coronary arteries, increasing risk of angina, myocardial infarction and possible cardiac arrest
What are the warning signs of CVS complications>?
↑↓ HR ↑↓ BP Palpitations Arrhythmias Lightheadness Loss of consciousness/fainting
