Anaesthesia in Gastroscopy and Colonoscopy

Adrian Castro (Bill) and Dr. Ross Wilson

Background – Gastroscopy and Colonoscopy Both very common procedures

In 20111; Over 115,000 colonoscopies Over 70,000 gastroscopies

Both allow for visualisation and biopsy Gastroscopy – gastritis, ulcers, cancer,

H. Pylori infection, acid reflux, hiatus hernia, food intolerance, ERCP..

Colonoscopy – IBS, IBD, polyps, cancer, diverticulum, angiodysplasia..

Role of Sedation and Anaestheia Relieve pts anxiety and discomfort of procedure

Reduce the pts memory of the event

Increase operator ease in performing the procedure

Improve outcome of the examination

Pre-op Anaesthetic Assessment - 1 Informed Consent

Details of sedation/analgesia/anaesthesia, as well as -benefits, risks, limitations, possible alternatives

History Past anaesthetic/sedation experiences + any adverse

effects Major organ abnormalities – CDV, resp, kidney, neuro,

gastro Airway features – snoring, sleep apnoea, stridor Medications and Allergies Past medical history – medical conditions and past surgeries Substance use – alcohol, tobacco, other Women - possibility of pregnancy?

Pre-op Anaesthetic Assessment - 2 Examination

Vitals – HR, BP, O2 saturation, RR, temp CDV and Resp assessment Airway Anatomy

Neck ROM Jaw Teeth Mallampati score

Inform patient of minimum fasting time2: 2hrs – clear fluids 6hrs – light solids

Pre-op Anaesthetic Assessment – 3 No data supporting routine pre-op investigations in elective

GI endoscopy3

Relevant Investigations based on the pts history and risk factors FBC EUC LFT BSL Coags Group and Hold CXR ECG

Particular Problems/Concerns Pregnancy Lactating Delayed gastric emptying Compromised CDV/Resp function Pts with renal or hepatic deficits Medication

Use of anti-thrombotics/anti-platelets Antibiotic therapy

General Technique Level of anaesthetic used may range from:

nothing conscious sedation sedation GA Things to consider:

Health status – comorbidities Current medications Procedure Age Weight Procedural anxiety Pain tolerance Patient preference

Medications used Sedation + pain relief – midazolam, propofol, fentanyl, sevoflurane Anti-emetics

Australian anaesthetists’ practice of sedation for GIT endoscopy in adult patients5 – combinations used

*Operator dependent; no optimal drug combination has been established for endoscopy 99 eligible respondents

1 – midazolam + fentanyl - gastroscopy 1 – Sevoflurane for ERCP 1 – Sevoflurane for colonoscopyFor the rest: 4% - Propofol 14% - Propofol + midazolam 6% - Propofol + fentanyl 61% - Propofol + midazolam + fentanyl 15% - Propofol + other drug (alfentanil, ketamine, remifentanil,

pethidine)

Australian anaesthetists’ practice of sedation for GIT endoscopy in adult patients5

Midazolam usage in gastroscopy correlated with years post-Fellowship <10 years – 76% >10 years – 92% Not statistically significant for ERCP or colonoscopy

Propofol dosing Bolus method preferred Infusion rates higher in ERCP > colonoscopy >

gastroscopy

Australian anaesthetists’ practice of sedation for GIT endoscopy in adult patients5 - Airway Management

Jaw Lift as required - G 97%, C 92%, E 80% Laryngeal Mask airway - 3%, 8%, 1% Endotracheal Tube - 0%, 0%, 19%

Consider use of ET tube if: Difficult airway to manage on assessment known aspiration risk

Propofol Used for induction + maintenance of anaesthesia,

conscious sedation, sedation during ventilation MOA – uncertain

GABAA potentiation slower closing time Sodium channel blocker Role of endocannabinoid system

Dose – conscious sedation Adult –

IV 0.5-1.0 mg/kg over 1-5 minutes IV 1.5mg/kg/hr maintenance Bolus of 10-20mg if rapidly needed

Propofol Duration of Effect (DOF) – 4-8 mins Pregnancy – possible CNS and resp depression Breastfeeding – appears safe Adverse effects

Common - pain on injection ~30%, bradycardia, hypotension, apnoea, flushed skin or rash, cough, induction excitation

Infrequent – arrhythmias, thrombosis, phlebitis Rare – anaphylactic reaction, seizure, fever,

pancreatitis

Midazolam Used for induction of anaesthesia, conscious sedation,

sedation during ventilation MOA – binds to benzodiazepine site

promotes binding of GABA to GABAAreceptors increase chloride entersneurons neuron hyperpolarisation less firing effects

Dose – conscious sedation Adult –

IV 2-2.5mg, 1-1.5 if elderly or debilitated 1mg doses as needed

Midazolam DOF – 15-80 mins Pregnancy – avoid in late 3TM and during labour Breastfeeding – limited data; highly protein bound, short

half life feed as usual after surgery Care: renal and hepatic impairment Adverse Effects

C – hypotension, hiccup, cough I – pain on injection, erythema, rash, laryngospasm,

bronchospasm, N/V, headache R – arrhythmia, cardiorespiratory arrest, anaphylactic reaction

Fentanyl Used as opioid adjunct during anaesthesia MOA – bind to opioid receptors (m, d, k) in central

and peripheral neurons G-protein coupled receptors inhibit neurotransmitter release decrease pain signals transmitted analgesia

Dose – Adult –

IV 50-100ug initially IV 25-50ug as required

Fentanyl DOF – 30-60 mins Pregnancy – prolonged high doses can cause

respiratory depression in newborn + withdrawal syndrome

Breastfeeding – Safe to use occasional doses of opioids Monitor for sedation or other effects

Adverse Effects C – rash, erythema, bradycardia, N/V, constipation R – chest wall rigidity (very high/rapid IV doses)

Sevoflurane Used for induction and maintenance of anaesthesia MOA – uncertain

Enhance inhibitory ion channel activity and inhibit excitatory activity in: brain hypnosis + amnesia Spinal cord – immobility in response to painful stimuli

Dose – Adults/child

Up to 8% inspired conc. in O2 +/- nitrous oxide; fresh gas flow >2L/min

0.5-3% +/- NO2

Sevoflurane

Pregnancy – safe Breastfeeding – no adverse effects expected Adverse Effects

C – shivering, N/V I – arrhythmias R – malignant hyperpyrexia

Intraoperative Monitoring/Intervention5

Recommended by ANZCA Oxygen administration Pulse oximetry Non Invasive BP

IV Fluids ECG Capnography

Complications Risks associated with various agents

Risk of aspiration

Surgical risks - GIT perforation, bleeding, infection

Post-op Management Patient extubated after awake and protecting

airway Handover to post-op staff and monitored ~1 hour

Oxygen therapy Pulse oximeter Blood pressure ECG Other vitals

Limitations for 24hr – no driving, operating heavy machinery, signing legal documents, drinking alcohol

References1. Australian Council on Healthcare Standards (ACHS). Gastrointestinal Endoscopy version 1. Retrospective data in

full. Australasian Clinical Indicator Report 2004–2011. Sydney NSW; ACHS; 2012

2. Lichtenstein DR, Jagannath S, Baron TH, Anderson MA, Banerjee S, Dominitz JA, Fanelli RD, Gan SI, Harrison ME, Ikenberry SO, Shen B, Stewart L, Khan K, Vargo JJ, Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy. Sedation and anesthesia in GI endoscopy. Gastrointest Endosc. 2008 Nov;68(5):815-26.

3. ASGE Standards of Practice Committee, Levy MJ, Anderson MA, Baron TH, Banerjee S, Dominitz JA, Gan SI, Harrison ME, Ikenberry SO, Jagannath S, Lichtenstein D, Shen B, Fanelli RD, Stewart L, Khan K. Position statement on routine laboratory testing before endoscopic procedures. Gastrointest Endosc. 2008, Nov;68(5):827-32.

4. Joo HS, Wong J, Naik VN, Savoldelli GL. The Value of screening preoperative chest x-rays: a systematic review. Can J Anaesth. 2005, Jun-Jul;52(6):588-74.

5. Padmanabhan U, Leslie K. Australian anaesthetists’ practice of sedation for gastrointestinal endoscopy in adult patients. Anaesth Intensive Care. 2008, May;36(3):436-41.

6. ASGE Standards of Practice Committee, Anderson MA, Ben-Menachem T, Gan SI, Appalaneni V, Banerjee S, Cash BD, Fisher L, Harrison ME, Fanelli RD, Fukami N, Ikenberry SO, Jain R, Khan K, Krinsky ML, Lichtenstein DR, Maple JT, Shen B, Strohmeyer L, Baron T, Dominitz JA. Management of antithrombotic agents for endoscopic procedures. Gastrointest Endosc. 2009, Dec;70(6):1060-70.

7. RACGP, PSA, ASCEPT. Australian Medicines Handbook 2011. Adelaide, SA. 2011.

8. Chahl LA. Opioids – mechanism of action. Aust Prescr. 1996;19:63-5.

9. Pardo M, Sonner JM. Manual of Anesthesia Practice – Pocket Clinician. 1st ed. New York: Cambridge University Press; 2007.