S&A 3 - IV sedation equipment and technique

Question 1

When is cannulation indicated in dentistry?

Answer 1

IV drug administration - prophylaxis/ medical emergency

IV sedation

Question 2

Where can a cannula be placed for IV sedation in dentistry?

Answer 2

Dorsal veins of hand - visible, superficial, no vital structures and splinted
Antecubital fossa - larger veins, danger of brachial artery & median nerve, and problems with joint movement

Question 3

What veins drain the hand?

Answer 3

Basilic and cephalic veins

Question 4

What equipment is needed for cannulation?

Answer 4

• 22g venous cannulae (g=gauge)
• 5ml syringe & 18 g needle (to draw up saline)
• 5ml 0.9% sterile saline (for irrigation)
• Drug label
• Tourniquet (occludes veins)
• Surgical wipe (for skin)
• Gloves, disposable tray, cotton wool rolls
• Non-allergenic tape (to secure cannula)

Question 5

What is the smallest and largest cannula sizes?

Answer 5

Smallest 22g (blue) - most comfortable 
Largest 14g (brown)

Question 6

What is the technique for cannulation?

Answer 6

• Draw up saline into 5ml syringe
• Select & check working order of cannula
• Select an appropriate vein
• Apply tourniquet, 10cm above cannulation site
• Wait for vein to become engorged
• Tense skin & insert cannula at an angle of 10-15 degrees
• Flash-back of blood indicates cannula in vein
• Withdraw the metal needle slightly (0.5cm) and advance cannula up to its hub
• Remove tourniquet & metal insertion needle & place end cap
• Secure cannula with tape & administers 2-5ml saline into injection port

Question 7

Appear placement of cannula and saline injected into port, why would a lump appear?

Answer 7

Lump shows cannula is subcutaneous, therefore need to remove and re-site

Question 8

What complications can arise when placing a cannula?

Answer 8

Difficult veins
Extra-venous cannulation - pain, subcutaneous lump, re-site
Intra-arterial injection - pain, bright red pulsating bloom remove and add pressure
Haematoma formation - avoid penetrating opposite wall by reducing angle of needle, remove cannula and pressure

Question 9

What is the procedure of IV sedation (when administering drug) in dentistry?

Answer 9

Titrate 5ml of midazolam
1mg injected slowly, wait 1 min and repeat
Titrate against effect on patient
End point flush with saline

Question 10

What is the arm-brain circulation of IV sedation with midazolam?

Answer 10

25 seconds

Question 11

What signs of sedation does the patient present with?

Answer 11

Slurred and slow speech 
Relaxed looking
Delayed response to commands 
Ptosis
Willingness for tx.

Question 12

How is a patient monitoring through IV sedation?

Answer 12

Arterial oxygen saturation
Pulse
BP
Clinical obs

Question 13

After IV sedation what is the recovery and discharge protocol?

Answer 13

Recovery - monitor arterial oxygen saturation for 1hr

Discharge - patient can walk in straight line, satisfactory BP and SaO2 levels, remove cannula and patient ESCORT

Question 14

What complications can arise with IV sedation?

Answer 14

Respiratory depression
Over-sedation
Disinhibition - react complete opposite - aggressive/uncooperative
Allergy

Question 15

In an emergency during IV sedation, how is midazolam reversed?

Answer 15

Flumazenil - 200ug initially

100ug/min (max 1mg)