SA Flashcards
Define conscious sedation and general anaesthesia
- reducing or stopping physiological responses without loss of consciousness, cooperation or protective reflexes. Used to ease discomfort/ stress/pain/anxiety
-depresses the CNS
-verbal contact remains
-GA= absence of sensation, without the ability to maintain physiology function such as breathing and protective reflexes. Carried out in hospital setting
What drugs is used for conscious IV sedation and its dose. What is its reverse drug
-midazolam 5mg/5ml (3mg total usually over 3 mins)
0.5mg - sedated, 25g anaesthetised
-flumazenil - 200ug initially, 100ug/min, 1mg max (only used in emergencies, not speeding up recovery)
Indications/ Types of patients that benefit from sedation
*Moderate dental anxiety/ phobias
*Children - Used more routinely as part of behavioural management (eg. if uncooperative)
*Medically compromised patients - Stress precipitates conditions e.g. asthma, angina, hypertension
*Special needs patients -poor cooperation with mild learning disability, cerebral palsy, Parkinson’s etc.
*Poor Gag and swallow reflex
*Persistent fainting
*Traumatic dental procedures (MOS, implants)
Contraindications for IV sedation
-Allergy
-Unwilling/uncooperative
-Unaccompanied- no escort available
-Very old - liver and kidney affects metabolism
-Children<12 -Sensitive to dosage with young people. Restless in chair (opt for GA as safer)
-Severe psychiatric disease
-Severe or uncontrolled systemic disease- e.g. recent MI, COPD
-Hepatic or renal insufficiency -Won’t metabolise the drug
-Pregnancy and breastfeeding
-severe needle phobia
-poor veins
-methotrexate?
-high BMI (if >36) or sleep apnoea- done in hospital)
-responsibilities- caring for children
-recent alcohol or rec drugs
Contraindications for RA sedation
-poor nasal airway- heavy cold, deviated septum
-Claustrophobic patients
-Middle Ear/Sinus Infection (nitrous oxide can go into air filled cavities and increase pressure in these areas)
-Certain types of occular surgery
-Behavioural problems/Personality disorders, poor cooperation
-URTI
-Severe anxiety
-1st trimester of pregnancy (if essential then do 2nd trimester and 30% max)
-Methotrexate?
-Bleomycin therapy
-COPD
What affect does methotrexate have with nitrous oxide
The drug Causes depletion of folate. With nitrous oxide can cause dangerous low levels of folate
Why bleomycin sulphate is contraindicated with nitrous oxide
- anti-neoplastic therapy
- due to the increased incidence of pulmonary fibrosis and other lung diseases.
- predisposed to respiratory failure following exposure to high concentrations of oxygen over 25%.
-Since use of 100% oxygen is part of the standard sedation procedure (in both the initial and recovery phases) there is an increased risk of possible problems in these patients.
Where does metabolism and excretion of IV and inhalation drugs occur
-IV: liver metabolism, kidney excretion
-RA: small metabolism in liver. Excretion in lungs
Types of drugs that increase risk of respiratory depression and drop in BP with midazolam
-Antihypertensives= HUGE DROP IN BP
-ritonavir (antiviral) = extreme risk of respiratory depression
What is included in patient assessment before sedation (RA and IV) Instructions given to pt
-suitability (why it is needed)
-record baseline HR, BP, respiratory rate, BMI, oxygen saturation
-give instructions. Discuss risks
- MH
-gain written consent
-check understanding of procedure
-explain they need an escort home (only for IV), light meal before hand, no alcohol or rec drugs prior (synergistic effect)
-ask if had previous sedation (can help indicate how much to give)
What is the ASA classification system
-American Society of Anaesthesiologists
-Classification based on physical status
-Allocation of patients to grades according to:
o Medical status
o Operative/anaesthetic risk
-Estimation of fitness for sedation or GA
- I to V
What is ASA I. What is their BP
-patient without systemic disease; a normally healthy patient
-minimal anxiety
<60 years old
< 140 / 90 BP
What is ASA II
-MILD systemic disease - well-controlled (asthma, non-insulin diabetes, anaemia)
-very phobic, overweight (BMI 30-40), pregnant, special needs, drug allergy, smoker, alcoholic
-OR any healthy patient >60 years old (slower physiology)
< 160 / 95 BP
What conditions fit in the classification of ASA III.
-MODERATE systemic disease; which limits function but is not incapacitating
-poorly controlled insulin diabetes, epilepsy, angina, COPD, asthma etc
-Chronic bronchitis or emphysema
-Congestive heart failure or thyroid disease
< 200 / 115 BP
BMI>40
What is ASA IV
INCAPACITATING SYSTEMIC DISEASE; which is a constant threat of life
- sepsis, ongoing cardiac ischemia
-<3 months Post MI or CVA or TIA or stent
-COAD or CHF requiring O2 therapy
-Uncontrolled dysrhythmias
-Blood pressure > 200 / 115
What is ASA V and VI
5=moribund patient not expected to survive 24 hours unless treated
6= brain dead
Why someone with insulin dependant diabetes (type I) is at risk during sedation
-likely will go hypo as cannot eat the morning of sedation however will still take insulin = glucose stores will be depleted rapidly and pt becomes hypo – difficult to tell this is happening when sedated
Which ASA classifications (I-V) are suitable for sedation in a GDP
*ASA I = Suitable for sedation in GDP
*ASA II= Suitable for sedation in GDP; with appropriate precautions
*ASA III= Increased risk > usually refer to hospital
*ASA IV / V = Life-threatening disease = must be treated in hospital (should be by an anaeshtetist)
Indications for cannulation in dentistry
1.IV drug administration
-Prophylaxis (antibiotic/steroid cover)
-Medical Emergency
2. IV sedation
Sites for cannulation. Pros and cons for each
- Dorsal veins of the hand
-Easily visible, superficial veins. No vital structures - Antecubital fossa (basilic, cephalic, median cubital veins)
-Large veins
-Danger of brachial artery & median nerve
-Problems with joint movement
Step by step technique of cannulation
-Draw up 0.9% saline into 5ml syringe
-Select 22g venous cannulae & check its working order
-Select an appropriate vein.
-Apply tourniquet, 10cm above cannulation site
-Wait for vein to become engorged (hand clenching, tapping vein)
-Alcohol Wipe surface
-Tense skin & insert cannula at an angle of 10-15 degrees through skin and into the vein
-A 1st flash-back of blood at white cap end indicates the cannula has entered the vein
-Withdraw the metal needle slightly (0.5cm) so can see needle end and flashback
-Advance cannula up to its hub
-Remove tourniquet
-Remove metal insertion needle & place end cap – be quick
-Secure cannula with tape & administer 2-5ml 0.9% saline into injection port (if lump appears then cannula is subcutaneous > so remove & resite)
-5mg in 5ml drawn into 5ml syringe. Injected 1mg every 1 minute
Complications that can arise during cannulation and how to overcome
1.Difficult Veins
=Be patient
2.Extra-venous Cannulation
-Pain on cannulation
-Formation of subcutaneous lump
=Resite cannula
3.Intra-arterial Injection
-Significant pain, bright red pulsatile blood
=remove needle, apply pressure (+/- refer)
4.Haematoma Formation
-Avoid multiple venepuncture
-Avoid penetrating opposite wall of vein
=apply Pressure after cannula removed
5. Pain in arm, fingers, back of hand
IV sedation procedure
-Cannulation
-Record arterial oxygen saturation (>97%) Respiratory rate, HR, BP every 5 mins
-Draw up midazolam 5mg/5ml in 5 ml syringe
-1mg injected slowly. Wait 1 minute. Then 1mg every minute thereafter
-Slow titration against to patient effect
-Flush with saline to make sure all in system
-Commence dental treatment
