complications of conscious sedation Flashcards
What is the definition of conscious sedation?
Patient is given a drug which depresses the CNS so that verbal contact with the patient can be maintained throughout the period of sedation
The drugs and techniques used should carry a margin of safety wide enough to render loss of conscious unlikely
Name 4 complications of cannulation
Any from:
- venospasm
- extravascular injection
- intra-arterial injection
- haematoma
- fainting
What is venospasm?
Also called disappearing vein syndrome
Veins collapse at attempted venepuncture
How is venospasm managed?
Time - gets worse with repeated attempts
Efficient technique - slow skin puncture makes it worse
Ask patient to wear gloves or put warm water on hands
What is extravascular injection and what does it cause?
Active drug injected into the interstitial space causing pain and swelling
Can delay the absorption of the drug
How is extravascular injection managed?
Prevention by good cannulation and using a test dose of saline
Treated by removing the cannula, applying pressure and reassuring the patient
Name 4 signs that are used to diagnose intra-arterial injection
Any from:
- pain on venepuncture
- red blood in cannula
- pain radiating distally from site of cannulation
- loss of colour or warmth to limb
- weakening pulse
How is intra-arterial injection prevented?
Avoid anatomically prone sites eg antecubital fossa
Palpate first
How is intra-arterial injection managed?
Monitor for loss of pulse, limb cold and discoloured
Leave cannula in situ for 5 minutes post drug
If no problems, remove the cannula
If symptomatic, leave the cannula and refer to the hospital
What is a haematoma and what causes it?
Extravasion of blood into soft tissues (bruising)
Due to damage to the vein walls - can be caused at venepuncture or during removal of cannula
How can haematomas be prevented?
Good cannulation technique - avoid multiple holes in vein wall
Pressure post-operatively from the operator
Take care with the elderly
How is haematoma treated?
Time
Rest
Reassurance
If severe, initial ice pack then moist heat after
Consider heparin containing gel
What causes fainting during venepuncture and how is this treated?
Anxiety related
Worse if patient has not eaten
Lie patient with feet up
What are the types of complications during IV sedation?
Hyper-responders
Hypo-responders
Paradoxical reactions
Oversedation
Allergic reactions
What is hyper-respondance in IV sedation and how is it prevented?
Deep sedation using a minimal dose
Use 1mg increments when titrating drug
What is hypo-respondance and how is it first managed?
Little sedative effect with large doses
First check the cannula is in the vein
What types of tolerance may cause hypo-respondance?
Benzodiazepine induced
Cross tolerance
Idiopathic
What is the threshold to abandon treatment with midazolam?
10mg
Can be up to 15mg with specialists
What are paradoxical reactions?
Patient appears to sedate normally but then reacts extremely to all stimuli
How are paradoxical reactions treated?
Relax the patient when stimuli is removed
Check for failure of LA
Do not add any more sedative - reverse the sedative
In whom are paradoxical reactions most found?
Immature teenagers
What is oversedation?
A loss of responsiveness
Patient has respiratory depression and loses the ability to maintain their airway and undergoes respiratory arrest
How should an allergic reaction during IV sedation be managed?
Do not use flumazenil to reverse - patient could be allergic to this also as it is a benzodiazepine
Manage anaphylaxis as if the patient is not sedated
What are the complications of inhalation sedation?
Oversedation
Patient panics
