SAFE SEDATION FOR PATIENTS WITH SPECIAL NEEDS

Dr John M LOWMA. (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

Noxious stimulation

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

Reducing sympathetic activity

Anxiety Sedation

Sympatholysis

Analgesia

Anxiolytics

Cold, Pain, Noxious Stimulus

Fear Factor Sympathetic activation

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

Sedation vs G A

Minimal Moderate Deep G A

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

Normal Adequate May not be adequate

Often inadequate

CVS functionNormal Usually

maintainedUsually 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

O2 / N2O /Sevoflurane

Excellent for induction (paediatrics) Short exposure to allow for i.v. access Unsuitable for long term use

Intra nasal spray

Maintenance of the airway

AMBU Bag readily accessible + / - Oxygen supplement Chin lift (teach D S A) Practical “tricks of the trade”

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

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

Patient Positioning

Soft elastic belt (for children)

Safety belt (adults) Blanket (sympatholysis) Minor movement tolerable

Patient Positioning

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

Propofoldi-isopropyl phenol

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

Propofol – Pharmacokinetics

Propofol – Pharmacokinetics

Guaranteed sedation…..

Propofol Pharmacokinetics

Propofol Pharmacokinetics for the rest of us

Propofol Pharmacokinetics for the rest of us

Propofol Pharmacokinetics for the rest of us

Bathtub Pharmacokinetics

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

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”

Individual Titration

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)

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

Monitoring and iv infusion

Oxygen supply

Contingency Equipment: Vital SignsTM Airway Pack

Contingency Equipment

Contingency Equipment

Contingency Equipment

Contingency Equipment

Utility Trolley

Utility Trolley

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.,

Fasting Instructions

6 hours - solids

Food and snacks Milk Milky drinks Fresh orange juice

2 Hours – clear fluids

Water Ribena Apple juice Orange squash

Range of procedures

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

Range of Dental Procedures

Paediatric – M O S Paediatric –dental restoration

Often minimal stimulation Pulpectomy will need LA

Combative / mentally handicapped

Range of Dental Procedures

Adult – M O S Dental Implants Aesthetic dentistry Mentally handicapped

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

Practical Aspects

Equipment – Mandatory ←→ Best Practice Protocols / Check List – for nursing staff Documentation

Pre-operative diagnosis – justify procedurePre-operative assessment – questionnaireWritten pre-operative instructions / fasting timeConsent for surgery – informed / explicitConsent for sedation – informed / explicitSedation - 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

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

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

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

CD-ROM Contents

EQUIPMENT Specifications GUIDELINES for clinical practice TEMPLATES for documentation POWERPOINT

Thank you very much

Mount Yotei, 羊蹄山 , Shikotsu Toya National Park, Hokkaido, Japan