Analgesia and Sedation in Endoscopic Surgery Marina Yiasemidou MSc Surgical Skills and Sciences
Aims of Sedation and Analgesia in Endoscopic Procedures Reduce pt’s anxiety and discomfort Safety Thorough investigation Medications of rapid onset, brief duration and fast recovery Sufficient intra and post procedural monitoring Cost effective
Sedation
Sedation Target state: Conscious (Moderate) Sedation state of depression of the central nervous system which allows for the procedure to take place verbal contact with the patient is maintained – If verbal contact is lost the pt should be monitored as if they were under general anaesthesia
Pre procedural assessment Assessing Sedation risk Significant cardiac or pulmonary disease Neurologic or seizure disorder Stridor, snoring, or sleep apnea Adverse reaction to sedation or anesthesia Current medications, drug and food allergies; Alcohol or drug abuse Time of last oral intake ASA Score
ASA Classification Class Description I The patient is normal and healthy II The patient has mild systemic disease that does not limit their activities (eg, controlled hypertension or controlled diabetes without systemic sequelae) III The patient has moderate or severe systemic disease, which does limit their activities (eg, stable angina or diabetes with systemic sequelae) IV The patient has severe systemic disease that is a constant potential threat to life (eg, severe congestive heart failure, end-stage renal failure) V The patient is morbid and is at substantial risk of death within 24 hours (with or without a procedure) E Emergency status: in addition to indicating underlying ASA status (1–5), any patient undergoing an emergency procedure is indicated by the suffix ”E”
Pre procedural assessment ASA class I–III patients - sedation by an endoscopist. Anesthesia specialist: ASA classes IV and V patients Emergency endoscopic procedures Complex endoscopic procedures Retrograde cholangiopancreatography Endoscopic ultrasound History of: Adverse reaction to sedation Alcohol or substance abuse Inadequate response to moderate sedation
Pre procedural assessment Fasting strictly for sedation reasons ASA :clear fluids 6hrs, NBM 2hrs Physical examination: Vital signs and weight Auscultation of heart and lungs Baseline level of consciousness, and Assessment of airway Identify patients with anatomy that may make positive-pressure ventilation more difficult (obesity, short thick neck, cervical spine disease, decreased hyoid-mental distance, and structural abnormalities of the mouth, jaw, and oral cavity)
Mallampati Score Picture A - Class 1 Score Picture B - Class 2 Score Picture C -Class 3 Score Picture D - Class 4 Score Class 1: Full visibility of tonsils, uvula and soft palate Class 2: Visibility of hard and soft palate, upper portion of tonsils and uvula Class 3: Soft and hard palate and base of the uvula are visible Class 4: Only Hard Palate visible
Sedation Techniques IV route Exact doses are variable – Min dose were possible PAIN=ANALGESICS Fentanyl Pethidine Opioids before diazepines (Colonoscopy and ERCP) Should be able to observe effect Titrate BZP dose - up to 4 fold decrease Synergy – Cardiovascular events Availability of antagonists/resuscitation equipment Flumazenil takes several min to reverse respiratory depression Repeated administration may be necessary
Sedation Techniques All pts undergoing IV sedation should have a flexible (not “butterfly”) IV cannula kept in place until recovery. Other Sedative drugs commonly used Propofol Should never be used without the presence of Ketamine a trained anaesthetist Entonox: 50/50 mixture of nitrous oxide and O2 Good analgesic Little hypnotic effect Mask or mouthpiece via a demand mask Compliance - Stops as sedation begins
Sedation Techniques Difficult pts Not safe: Compromised respiratory function Pneumothorax Best suited for colonoscopy or flexible sigmoidoscopy Rapid recovery: Washout time: 5-10 min Difficult pts Restless and Violent pts GA is the better option if anticipated Reverse sedation if procedure already begun Alcoholics Cannot be sedated with benzodiazepines Prior administration of opioid
Monitoring For pts under sedation saturation <90% is dangerous and requires immediate intervention. Endoscopist Clinical monitoring Trained nurse Pre-oxygenation with O2 enriched air (2L/min) Safe even in COPD Prevents hypoxaemia SHOULD BE USED ROUTINELY
Monitoring Pulse Oximetry ALWAYS Alarm System Desaturation Clinical observations should still be employed High cardiac risk + Continuous ECG monitoring and BP monitoring Desaturation Encourage pt to breath deeply with supplemental O2 Termination of procedure Assisted Ventilation Pharmacological Reversal of diazepine/opioid
Patient Recovery Clinical monitoring must be continued into the recovery period Respiratory complications such as aspiration pneumonia may present many hours or even days after the endoscopy. Endoscopist is still responsible Day cases should be accompanied home by a responsible adult who should then stay with them for at least 12 hours if they live alone. Written instructions Patients who have been sedated with an intravenous benzodiazepine should not drive a car, operate machinery, sign legal documents or drink alcohol for 24 hours.
Patient Recovery-Aldrete Scoring Score ≥ 9: Can be discharged
Review of common drug agents Midazolam is currently the corner stone of endoscopy sedation Several times more potent than diazepam Excellent amnesia Inexpensive 5mg is the recommended max dosage Elderly pts are given 1-2mg with a considerable pause to observe effects
Review of common drug agents Opioids: Pethidine – Fentanyl Pethidine has greater synergistic effect on sedation when given in combination with midazolam Higher rates of postprocedural emesis, nausea and reduced pt functioning Pethidine and Fentanyl dosage does not usually exceed 50mg and 100mg respectively Elderly pts will require dose reduction (usually below 50%)
Review of common drug agents Propofol Anaesthetic agent Acts via releasing aminobutyric acid in the brain Fast onset, short action, rapid recovery Can be titrated so as to produce deep sedation or general anaesthesia Difficult to use as a single agent for moderate anaesthesia Colonoscopy: Unpredictable reflex responses to pain Upper Endoscopy: Oesophageal intubation initiates coughing Pts that cannot be sedated with opioids and benzodiazepines – small amounts of propofol or droperidol
Review of common drug agents Droperidol Active alcohol or substance abuse Produces prolonged QT arrythmias Pre procedural ECG Continuous monitoring during the procedure When contra indicated Diphenhydramine or Promethazine (prolonged sedative effect)
Review of common drug agents The antagonists Naloxone Opioid antagonist Ventilatory depression, excessive sedation and analgesia Dose of 0.2-0.4 mg IV Onset 1-2 min, half life 30-45 min Monitor for up to 2 hours Caution for drug withdrawal symptoms in chronic opioid drug abusers
Review of common drug agents Flumazenil GABAA receptor complex BZP antagonist 0.1-0.3 mg Half life = 0.7-1.3 hrs Reversal of respiratory depression 2min BZP has longer time of action – Repeated administration might be necessary
References Implementing and ensuring Safe Sedation Practice for Healthcare Procedures in adults. Report of a Working Party established by the Royal College of Anaesthetists, www.aomrc.org.uk November 2001 Sedation for Endoscopy. Douglas K. Rex.Division of Gastroenterology, Indiana University Medical Center, Indianapolis, Indiana http://www.emsresponder.com/publication/article.jsp?pubId=1 &id=6894 AGA Institute Review of Endoscopic Sedation. LAWRENCE B. COHEN, MARK H. DELEGGE, JAMES AISENBERG, JOEL V. BRILL, JOHN M. INADOMI, MICHAEL L. KOCHMAN, and JOSEPH D. PIORKOWSKI JR
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