local complication pt1

Local Complications of Anesthesia

Syncope

• Form of neurogenic shock caused by cerebral ischemia secondary to vasodilation or increase in peripheral vascular bed with a corresponding drop in blood pressure
• Management:
  • Discontinue procedure
  • Place patient in semi-reclining position with legs and thorax slightly elevated
  • Check vital signs
  • Reassure patient
  • Determine degree and extent of paresthesia
  • Explain to patient that paresthesia normally persists for 2 months before resolution begins and may persist up to 1 year or longer
  • Reschedule patient for examination every 2 months
  • Record findings on patient's chart

Trismus

• Motor disturbance of the trigeminal nerve, especially spasm of the masticatory muscle, with difficulty in opening the mouth
• Caused by trauma to muscles or blood vessels, injection of contaminated solution, hemorrhage, or low-grade infection
• Management:
  • Heat therapy: moist heat 20 minutes every hour
  • Analgesic
  • Muscle relaxation: diazepam 10mg q 12 hours
  • Physiotherapy: opening and closing as well as lateral excursions of mandible for 5 min q 3-4 hours

Needle Breakage

• Extremely rare complication
• Caused by sudden, unexpected movement by the patient as the needle penetrates the muscle or contracts periosteum
• Prevention:
  • Use larger gauge needles (25 or 27 gauge)
  • Use long needles for injections requiring deep penetrations
  • Do not insert a needle into tissues to the hub
  • Do not redirect the needle once inserted into tissues

Pain on Injection

• Caused by careless injection technique and callus attitude, use of dull needle from multiple injections, and rapid deposition of solution
• Increases patient anxiety and may lead to sudden, unexpected movement, increasing the risk of needle breakage
• Management:
  • Reassure patient
  • Determine the degree and extent of paresthesia
  • Explain to patient that paresthesia normally persists for 2 months before resolution begins and may persist up to 1 year or longer

Burning on Injection

• Caused by pH of the solution, rapid injection, and injection of contaminated local anesthetic solution by sterilizing solution
• If caused by pH of the solution, there is usually no residual sensitivity when the anesthetic action terminates
• If caused by rapid injection and contaminated solution, tissue will be damaged with subsequent postanesthetic trismus, edema, or possibly paresthesia

Paresthesia

• Caused by trauma to the nerve, injection of contaminated solution, direct contact of nerve with needle, and hemorrhage into or around the neural sheath
• Most cases resolve in approximately 8 weeks without treatment
• Most cases involve the lingual nerve, with the inferior alveolar nerve a close second

Infection

• Extremely rare occurrence since the introduction of sterile, disposable needles and glass cartridges
• Caused by use of contaminated needles, improper technique in handling LA equipment, and improper tissue preparation for injection
• Prevention:
  • Use disposable needles
  • Recap the needle when not in use
  • Avoid multiple injections with the same needle
  • Use dental cartridges and store them aseptically in the original container, covered at all times
  • Cleanse the diaphragm with sterile, disposable alcohol wipes
  • Dry the tissue and apply topical antiseptic

Overdose

• Over administration of a drug produces elevated levels of the agent in the blood
• Caused by too large a dose of local anesthetic agent
• Maximum dose of local anesthesia (healthy adult):
  • 2% lidocaine: 4.4 mg/kg up to 300mg
  • 2% lidocaine with vasoconstrictor: 7 mg/kg up to 500mg
  • 3% mepivacaine: 6.6 mg/kg up to 400mg
  • 2% mepivacaine with vasoconstrictor: 6.6 mg/kg up to 400mg
  • 0.5% bupivacaine: 2mg/kg up to 175mg
  • 1.5% bupivacaine with vasoconstrictor: 2mg/kg up to 225mg