Pain and Anxiety Flashcards
Basic behavioural management strategies
Tell, show, do Positive distraction - music Relaxation Systemic desensitisation - d=gradual acclimatisation Hyponosis Advanced behavioural - psychology
Ideal sedation agent
Rapid onset Predictable action/duration Low incidence of side effects Simple to administer Rapid recovery Rapid metabolism/excretion
Sedation guidelines: Poswillo report (1990, DoH) A Concious Decision (2000, DoH) Standards for Concious Sedation in the Provision of Dental Care - The Dental Faculties of the RCS and RCA (2015) SDCEP - Concious sedation in dentistry
Oral sedation
Oral premedication at home:
Diazepam 2-5mg morning of
Temazepam 10mg night before - helps pt sleep as well
Ask GMP for advice/prescribe
Oral premedication in surgery:
Temazepam 10-20mg/10mg Midazolam, with monitoring
Oral sedation is - simple to administer, predictable action/duration, low incidence of side effects
Inhalation sedation
Requires specialist surgery/techniques/training Good for children Patent nasal airway Minimal intervention Analgesic Hazards of chronic exposure
IHS is: predictable action/duration, rapid onset, rapid metabolism/excretion, rapid recovery, simple to administer, low incidence of side effects
Intravenous sedation
With pulse oximeter monitoring With midazolam - titrated as needed Anticonvulsant Muscle relaxant Anterograde amnesia Good 20-30 mins sedation Minor respiratory/cardio depression No analgesic effects
Side effects: Over sedation Cardio depression Respiratory depression Tolerance Sexual fantasy
IV sedation is: rapid onset, predictable duration, low incidence of side effects, rapid recovery, simple to administer
Minimal sed vs mod sed vs deep sed
RAVC
Minimal sed - normal response to verbal commands, airway unaffected, ventilation unaffected, cardiovascular unaffected
Mod sed - purposeful response to verbal or tactile stimulation, airway maintained w/o intervention, ventilation adequate, cardiovascular usually maintained
Deep sed - purposeful response following repeated or painful stimulation, airway may require intervention, ventilation may be inadequate, cardio usually maintained
Blood pressure determined by:
2 main components:
CO and SVR
CO: amount of blood ejected by heart per min - ave = 5L/min
Determined by HR and SV
HR between 50-180 has little effect
SV affected by - anaethetic drugs, dehydration/blood loss, ischaemic HD/HF
SVR: systemic vascular resistance. Mainly due to arterioles. Constriction = increased SVR, increased BP
Dilation = decreased SVR, low BP
SVR decreased by: sedative drugs, anaphylaxis, sepsis/infection
Acute and chronic BP control
Acute:
Baroreceptors in aortic arch and internal carotids
Send signals to brain stem
ANS alters rate and strength of heart contraction and constriction of BVs
Chronic:
Renin-angiotensin system
Aldosterone hormone
Chronic regulation of blood Na and body fluid retention
Midazolam:
Method of action, dose, reversal
Benzodiazepine - binds to benzo binding site and GABA binds to GABA binding site and activates opening of receptor channels causing influx of Cl- ions into cell, decreasing ability to initiate AP = sedative effect
Usual conc 5mg/ml
IV for moderate sedation
Onset 1-3 mins
Peak 5-7 mins
Duration 20-30 mins
Titre until desired end point e.g. slurred speech
Half life 1-2.8 hours. Increased 1/2 life if elderly, other meds, sepsis, poor renal function
Initial dose = 2.5mg over 2 mins Wait 2 mins for effect Subsequent doses 1mg Usually no more than 5 total Cautions - decrease initial dose to 1.5mg in elderly and if pre-med given, then decrease dose by 1/3rd
Opiates e.g. Fentanyl
Opiates for analgesia but can have sedative effect at higher doses Fentanyl: Man made synthetic opiate Analgesia and sedation Onset 1-2 mins Peak 10-15 mins Duration 30-60 mins Dosing - 25mcg (0.5ml) bolus up to 200mcg max
+ analgesia as well as sedation
+ fast onset
+ short duration action
- hypotension and bradycardia
- resp depression
- nausea and vomiting
Pulse oximetry
Way of measuring O2 sats
2 diodes - light emitting and photodetector. Emits light into nail bed capillaries and light reflected back is picked up and calculated as % o2 saturation (Ho2 has diff absoprtion of light to xHo2 blood)
Limitations: Ambient light Movement Cold peripheries - cause vasoconstriction, less blood flow into nail capills Nail varnish/false nails Measurement lag - 30-60 seconds
Capnography - detects exhaled CO2 in breath via nasal prongs. Pt must be breathing through nose
Upper airway obstruction
Sedation decreases muscle tone of muscles in pharynx
Leading to pharyngeal collapse - tongue falls against back wall of pharynx
Total or partial airway obstruction
Signs of airway obs: Snoring Stridor Drop in O2 sats Loss of CO2 trace Seesaw respiration
Management: Supplementary O2 Careful titration of sedation Airway opening maneuvers - jaw lift, chin lift Airway adjuncts
Hypoventilation
Sedation also sedate resp centres in brain
Reduce receptor sensitivity to CO2
Leading to reduced resp rate or complete cessation breathing
CO2 level can build up leading to necrosis
Detection: monitoring of resp rate, drop in o2 sats
Mgt: reversal with Flumazenil for midaz or Naloxone for fenty
Self inflating ambubag for assisted ventilation
Hypotension
Sedative drugs can cause vasodilation
Some drugs decrease strength of heart contractions
Dose related - titre little by little and if elderly or existing heart condition, reduce by 1/3rd
More likely to occur in elderly and those with existing cardiovascular disease
Txt: prevention better than cure - if dehydrated, recent heart attack (6mo), long bleeding time, consider procedure elsewhere
Stop administering agent
Place pt head down feet elevated
IV fluids may be required
Cardiac arrhythmia / cardiac arrest
Multi factorial aetiology
May be precipitated by adrenaline in LA
More likely in elderly and those with CVS disease
Raised blood co2 levels also increase risk
Txt: call for expert help, advanced life support algorithms
Cardiac arrest - worst complication. Prevent by doing above. If high risk - refer. If suspect going from mod to deep sedation then wind down
Basic life support
Advantages of IV sedation
Given remote from operating site Excellent amnesia Mouth breathing not important Given as single dose No pollution of surrounding environment Rapid onset Patient cooperation less important Sedation attained pharmacologically
Disadvantages of IV sedation
No clinically useful analgesia
Pre and post op instructions must be followed
Sexual fantasies
Occasional disinhibition effects
Laryngeal reflexes obtunded for short period
Overdose can lead to profound respiratory depression
Pt assessment
Must justify why IV sedation over another technique e.g. time and TLC, LA, psychotherapy, hypnosis, acupuncture, IHS, oral sed, GA
MH
ASA score
DH
SH - escort, post-op care, work, transport
Physical assessment - colour, pulse, respiration, arterial o2 sat, BP, weight/BMI, degree of understanding and cooperation
Clinical effects of IV midaz
Anxiolytic - relieve anxiety Hypnotic Sedation Amnesia Anti-convulsant Decrease in skeletal muscle tone
Contraindications to IV sedation
Allergy to benzos Pregnancy at any stage Age ASA III, IV, V Poor veins High or very low BMI Those with respiratory depression Those with complex lung conditions that cause acute pulmonary insufficiency Those with severe hepatic impairment Those with sleep apnoea - not suitable as outpatient
Midazolam contraindications
Hypersensitivity to benzos
Myaesthenia gravis - chronic autoimmune disorder causing weakness in skeletal muscles
Shock or vital sign depression
Acute narrow angle glaucoma - potential to cause blindness due to high pressure in eye damaging optic nerve
Be careful when pt on other form of benzo, takes social drugs (e.g. cannabis), alcohol abuse, other sedatives
Flumazenil
Reverses effects of benzos 200mcg every 1-2 mins as required Onset 1-2 mins, peak 6-10 mins Competitive inhibitor of benzos Elimination half life = 53 mins Potential for resedation due to shorter half life of F to M
Venepuncture
IV access with cannula
IA - accidental. If pre-drug, remove cannula and apply pressure for extended period. If post-drug, contact local vascular surgeons - medical emergency
Transfixation - cannula passes through vein
Haematoma - bleeding into tissue due to lack of pressure or leakage from vessel
Embolism - foreign body
Pharmacokinetics / pharmacodynamics of NO2
Pharmacokinetics:
Inhaled into lungs through nasal mask
Travels down partial pressure gradients - though lungs - alveolus - bloodstream/capillaries
Hardly metabolised - excreted through lungs
Elimination half life - 5 mins
Pharmacodynamics: Analgesic Anaesthetic - still need LA Hypnotic Anxiolytic - acts on GABA
Stages of anaesthesia:
- Analgesia - most dental procedures within this
- Excitement
- Surgical analgesia
- Respiratory paralysis
Signs of oversedation - IHS:
Hysterical laughter, tears No longer enjoying effects Decreased cooperation Nausea/vomiting Mouth closing repeatedly Snoring Incoherent speech Irrational and sluggish responses Loss of conciousness ultimately
Contraindications IHS:
Social
Medical
Dental
Social: Claustrophobia No consent No escort Severe anxiety Lack of understanding of treatment
Medical:
Blocked nose/URTI/unable to breathe through nose
Myasthenia gravis
Pregnancy
Bleomycin therapy
Recent surgery eye/middle ear/intracranial/sinus
Dental:
Traumatic procedures
Txt of upper anterior teeth
Safety features IHS
Pin index - tube only fits to specific gas so cant give wrong one
Scavenging at 40L/min - legal requirement. Important so dental team dont inhale gas. Removes any gas exhaled by pt - check within 2 blue lines
Nasal mask and tubing - check no holes
Oxygen failsafe - if O2 stops, nitrous oxide will stop too to prevent giving 100% nitrous
Mayx 70% N2O - unable to give more
Oxygen flush - delivers high rate oxygen through mask in oversedation emergency
Air entrapment valve - ensure clear and no obstruction of holes
Reservoir bag - monitor how well pt breathing, check expiry
IHS pre-op instructions
Light meal
Take routine medications as normal
Children must be accomapanied by competent adult
No other kids
Can cause dizziness/headache.nausea at higher doses
IHS - technique:
Safety checks, consent, escort
Introduce to child - let them feel mask, giggle gas, what they will feel/experience, nice sensation
Start oxygen and turn up flow rate 5-6L/min
Fit mask and encourage nose breathing - let pt put mask on nose, tighten, practice nose breathing with 100% O2
Titrate N2O at 10% per min to 30% then 5% per min until adequate sedation
Hypnotic suggestion, clinical monitoring
100% O2 min. 3 mins to recover
Advantages IHS
Non-invasive
Drug easily altered/discontinued
Minimal impairment reflexes
Drug administered and excreted via lungs - no metabolism so rapid recovery
No fasting required
No escort for adults
Some analgesia - 50%N2O equiv to 10mg morphine
Disadvantages IHS
Lack of potency of nitrous oxide - not as good as IV sed with midaz
Expensive equipment - maintenance exp
Space occupying equipment
Patient perception of equipment
Difficulty treating upper anterior teeth
Lack of control of pt cooperation - if pt doesn’t breathe through nose, wont work
Requirement of clear nasal airway
Chronic exposure of staff
Potential for staff addiction
Contraindications to IHS
Respiratory tract infection
Nasal obstruction
Severe personality disorders
Pt’s taking methotrexate - can increase toxicity
Myaesthenia gravis
MS
Pt’s with claustrophobia
Treatment that will be obstructed by mask
Psychiatric disorders
Pregnancy - esp 1st trimester
Recent ophthalmic surgery using intraocular gases
Cyanosis at rest due to chronic cardiac or resp disease
Severe chronic pulmonary condition
Process for hypnosis
Preperation - prepare pt to feel good about whats coming
Induction - intro to process
Deepening - increase physical relaxation and intensity of image to help pt disassociate
Specific suggestions/imagery
Post-hypnotic suggestions
Alerting - confirm pt is fully back to their senses
