Safe Sedation for patients with special needs Dr John M LOW MA. (Oxford University) BM.BCh. (Oxford University) FRCA., FHKCA., FANZCA., FHKAM.(Anaesthesiology) Partner, Dr. Roger Hung and Partners

Overview Sedation vs General Anaesthesia Achieving sympatholysis Pharmacology Practical aspects of M A C - equipment Regulatory aspects Managing patient work flow

↑sympathetic activity Psychological and emotional Physical Instrumentation / Surgical Incision Pharyngeal/ Laryngeal stimulation Tomori Z, & Widdicombe J G (1969) J Physiol (London) 200:25 Exogenous catecholamines (LA) Cold Full bladder JM Low et al (1986)B J A 58:471-477

Noxious stimulation JM Low et al (1986) B J Anaesth 58:471-477 Adrenergic Responses to Laryngoscopy JM Low et al (1986)B J A 58:471-477

Reducing sympathetic activity Anxiety Cold, Pain, Noxious Stimulus Fear Factor Sympathetic activation Sedation Sympatholysis Analgesia Anxiolytics JM Low et al (1986)B J A 58:471-477

Reducing sympathetic activity Anxiolytics (benzodiazepines / propofol) Local analgesia - ↓ pain stimulus Fentanyl - ↓ pain stimulus; sympatholysis ↓ non-pharmacological factors (eg. cold) β - adrenergic blockade α - adrenergic blockade JM Low et al (1986)B J A 58:471-477

Sedation vs G A Minimal Moderate Deep G A Response to deep pain Responsiveness Verbal commands Purposeful response Response to deep pain Unrouseable Airway Normal No need for intervention May need chin lift Airway / chin lift needed Spontaneous ventilation Adequate May not be adequate Often inadequate CVS function Usually maintained May be impaired

Common drugs for sedation IV Sedation: Pethidine / Morphine Midazolam / Diazepam/Diazemuls Monitored Anaesthetic Care Propofol / Dexmetatomidine (Precedex) Fentanyl / Alfentanil / Remifentanil Dynastat / Pethidine

Typical sequence - M A C Assessment and Informed consent Preparation of equipment Inhalational induction (paediatric case) IV access – Bolus and Maintenance Maintenance of patient’s airway Monitoring Recovery and Discharge

Dr John M LOW <johnmlow@Uusa.net> O2 / N2O /Sevoflurane Excellent for induction (paediatrics) Short exposure to allow for i.v. access Unsuitable for long term use HKIDEAS 2010

Intra nasal spray

Maintenance of the airway Dr John M LOW <johnmlow@Uusa.net> Maintenance of the airway AMBU Bag readily accessible + / - Oxygen supplement Chin lift (teach D S A) Practical “tricks of the trade” HKIDEAS 2010

Dr John M LOW <johnmlow@Uusa.net> Practical “tricks” Posture – (take advantage of pharyngeal curvature) Horizontal position Neck extension Shoulder support Nasopharyngeal airway Loose gauze swab in pharynx Oral Dam Double suction (DSA) No irrigation – soft debris HKIDEAS 2010

Irrigation without aspiration Dr John M LOW <johnmlow@Uusa.net> Irrigation without aspiration Suction…..Suction……Suction……. Neck extension – double articulation headrest Cough / swallowing reflex present Oral Dam – if possible Loosely packed gauze swab Chin Lift -Train D S A Minimise irrigation HKIDEAS 2010

Dr John M LOW <johnmlow@Uusa.net> Patient Positioning Soft elastic belt (for children) Safety belt (adults) Blanket (sympatholysis) Minor movement tolerable HKIDEAS 2010

Dr John M LOW <johnmlow@Uusa.net> Patient Positioning HKIDEAS 2010

M A C – typical sequence

M A C – a pragmatic approach Inhalational techniques Excellent for paediatric induction No scavenging – closed ventilation Limited supply of gas / agent Complex equipment needed for maintenance Intravenous Techniques Propofol……propofol……propofol + / - Adjunct agents JM Low et al (1986)B J A 58:471-477

Propofol di-isopropyl phenol JM Low et al (1986)B J A 58:471-477

Propofol Pharmacology Non-barbituarate hypnotic anaesthetic Lipid soluble – preparation as emulsion Rapid hepatic & extra-hepatic metabolism Very rapid onset and recovery Half Life: T½= 2; 30; 180 mins Metabolites not active Hypnosis at 1.5-6 μg/ml Maintenance with infusion pump No atmospheric pollution JM Low et al (1986)B J A 58:471-477

Propofol – Pharmacokinetics JM Low et al (1986)B J A 58:471-477

Propofol – Pharmacokinetics Guaranteed sedation….. JM Low et al (1986)B J A 58:471-477

Propofol Pharmacokinetics JM Low et al (1986)B J A 58:471-477

Propofol Pharmacokinetics for the rest of us JM Low et al (1986)B J A 58:471-477

Propofol Pharmacokinetics for the rest of us JM Low et al (1986)B J A 58:471-477

Propofol Pharmacokinetics for the rest of us JM Low et al (1986)B J A 58:471-477

Bathtub Pharmacokinetics JM Low et al (1986)B J A 58:471-477

In practice Loading dose – 40-80 mg (1 mg/kg) Maintenance dose – 25-60 mls/hr (80 μg/kg/min) 20mg bolus prn. Titrating to patient’s threshold JM Low et al (1986)B J A 58:471-477

Titrating to patient’s threshold At steady state Reduce rate by 10% every few minutes Slight non-purposeful movement (threshold) Add 10% and maintain Switch off when no more stimulation “Every anaesthetic is a pharmacological experiment” JM Low et al (1986)B J A 58:471-477

Individual Titration JM Low et al (1986)B J A 58:471-477

Supplementary Agents Midazolam (1-2 mg) Fentanyl (25 mcg / 0.5 mls) Pethidine 0.5-1 mg/kg Remifentanil (20μg + 2.5 μg/min) Dynastat (40 mg iv Q12H) Arcoxia (90 – 120 mg po.) Dexmetatomidine (Precedex) Labetalol (!) (5 – 15 mg) JM Low et al (1986)B J A 58:471-477

Sedation - equipment IV equipment Monitoring Oxygen / AMBU bag Simple airway management Treatment of major side effects Anaphylaxis Extremes of HR Extremes of BP Bronchospasm Angina P O N V JM Low et al (1986)B J A 58:471-477

Monitoring and iv infusion Dr John M LOW <johnmlow@Uusa.net> Monitoring and iv infusion HKIDEAS 2010

Dr John M LOW <johnmlow@Uusa.net> Oxygen supply HKIDEAS 2010

Contingency Equipment: Vital SignsTM Airway Pack Dr John M LOW <johnmlow@Uusa.net> Contingency Equipment: Vital SignsTM Airway Pack HKIDEAS 2010

Contingency Equipment Dr John M LOW <johnmlow@Uusa.net> Contingency Equipment HKIDEAS 2010

Contingency Equipment Dr John M LOW <johnmlow@Uusa.net> Contingency Equipment HKIDEAS 2010

Contingency Equipment Dr John M LOW <johnmlow@Uusa.net> Contingency Equipment HKIDEAS 2010

Contingency Equipment Dr John M LOW <johnmlow@Uusa.net> Contingency Equipment HKIDEAS 2010

Dr John M LOW <johnmlow@Uusa.net> Utility Trolley HKIDEAS 2010

Dr John M LOW <johnmlow@Uusa.net> Utility Trolley HKIDEAS 2010

Patient selection ASA I or II Age less than 70 years BMI less than 30 Satisfactory pre-op assessment questionnaire Easy access to hospital if necessary Escort available following procedure

What procedures are appropriate ? Patient factors – ASA I / II Assessment of surgical risk Exclude risk of major bleeding Minimal risk of P O N V Satisfactory post-op pain control Patient’s domestic circumstances Why does this surgery justify hospitalisation ?

Patient Work Flow Presentation and decision to operate Screening Questionnaire Concurrent medications / Allergies / Cardio- respiratory status Fasting instructions Day of procedure – Consent; Contact; Re-assessment; Payment Recovery Stage I Stage II Escort to and from clinic Written Instructions – Medication; Analgesia; driving, machinery, signing of legal documents, cooking, etc., JM Low et al (1986)B J A 58:471-477

Fasting Instructions 6 hours - solids 2 Hours – clear fluids Food and snacks Milk Milky drinks Fresh orange juice 2 Hours – clear fluids Water Ribena Apple juice Orange squash JM Low et al (1986)B J A 58:471-477

Range of procedures Examination -/+ x-ray Dental Hygiene Restoration S S crown R C T Extraction Orthodontics -/+ impression

Range of Dental Procedures Dr John M LOW <johnmlow@Uusa.net> Range of Dental Procedures Paediatric – M O S Paediatric –dental restoration Often minimal stimulation Pulpectomy will need LA Combative / mentally handicapped HKIDEAS 2010

Range of Dental Procedures Dr John M LOW <johnmlow@Uusa.net> Range of Dental Procedures Adult – M O S Dental Implants Aesthetic dentistry Mentally handicapped HKIDEAS 2010

Clinic Selection Preliminary visit to clinic – assess environment Establish rapport with surgeon “Check List” of mandatory equipment Second visit – check all facilities Then – (third visit) - book patient JM Low et al (1986)B J A 58:471-477

Practical Aspects Equipment – Mandatory ←→ Best Practice Protocols / Check List – for nursing staff Documentation Pre-operative diagnosis – justify procedure Pre-operative assessment – questionnaire Written pre-operative instructions / fasting time Consent for surgery – informed / explicit Consent for sedation – informed / explicit Sedation - vital signs record / positioning / drugs / timetable of events Operation Record – diagnosis / findings/ procedure / closure Written Post-Operative instructions – escort present

Regulatory aspects American Society of Anesthesiologists American Dental Association Task Force of Sedation & Analgesia Practice Guidelines for Sedation Anesthesiology 2002 96:1004-1017 JM Low et al (1986)B J A 58:471-477

Regulatory aspects International Guidelines ASA / ADA* AAGBI / NICE Guidelines NHS UK* ASA Day Case Surgery Guidelines* Hong Kong College of Anaesthesiologists* Hong Kong Academy of Medicine* HK Society of Paediatric Dentistry* Mid Lothian Day Case Surgery Process Chart* * Copies included in CD-ROM

Useful Reference Texts Manual of Office-Based Anesthesia Procedures Fred E Shapiro Lippincott Williams & Wilkins www.amazon.com Guidelines on Sedation for Dental Procedures HKSPD Task Force www.hkspd.org American Heart Association – Emergency Cardiac Care A H A / Worldpoint www.eworldpoint.com)

Are there additional risks ? No greater or less than hospital setting ASA Closed Claims analysis Greater need for contingency planning Emergency Protocols Staff training in BCLS ACLS Simulate Drills (e.g. hypoxia) http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2044.2011.06651.x/pdf

Contingency Planning Oxygen (Cylinder /Oxygen Concentrator) Sedation Drugs Resuscitation Drugs Prolonged Recovery P O N V Vaso-vagal sycope Protocol for hospitalisation Local Analgesia Toxicity (Malignant Hyperpyrexia)

Emergency Drugs P O N V – metoclopramide / odansetron / dexamethasone Hypotension – phenylephrine / ephedrine Hypertension – nifedepine / labetalol / hydrallazine Bradycardia – atropine / isoprenaline / dobutamine Tachycardia – esmolol / fentanyl Bronchospasm – ventolin inhaler / aminophylline Acute Angina – nitroglycerine patch / sl. Anaphylaxis – adrenaline / Ca++ / hydrocortisone / dexamethasone Allergy – chlorpheniramine Antagonists – naloxone / flumazenil

Fitness for discharge Stable vital signs Orientation – time, place, person Satisfactory pain control Able to dress; walk; pass urine No bleeding ; No P O N V ; Escort present

Modified Aldrete Score

Post Anaesthesia Discharge Score (Korttila)

Discharge Work Flow Discharge Criteria- Modified Aldrete Score / PADSS (Korttila) Post-operative Instructions – written Escort is mandatory Supply of post-op drugs – analgesic; antibiotics Emergency contact number - nurse / surgeon Initiate telephone follow up on the next day Post operative follow up in clinic Alert system for pathology result (malignancy)

Benefits of O B A One Stop for the patient / client Control over scheduling No waiting for hospital beds Less competition for OT schedule No delay because of emergency OT Minimal risk of hospital acquired infection Reduced cost for patient and insurance

Dr John M LOW <johnmlow@Uusa.net> Summary M A C is safe Separate Operator and Sedationist M A C is a growing market Trends in USA: OBA - >50% services Recent adverse publicity locally (gynaecology; liposuction; mammoplasty) Follow guidelines HKIDEAS 2010

Dr John M LOW <johnmlow@Uusa.net> Summary M A C is safe ( “Big MAC” may not be) Separate Operator and Sedationist M A C is a growing market Trends in USA: OBA - >50% services Recent adverse publicity locally (gynaecology; liposuction; mammoplasty) Follow guidelines HKIDEAS 2010

CD-ROM Contents EQUIPMENT Specifications GUIDELINES for clinical practice TEMPLATES for documentation POWERPOINT

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