Sedation/Analgesia For Gastrointestinal Endoscopy

1. Sedation/Analgesia For Gastrointestinal Endoscopy Presented by Ting-Jui, Kang

2. Guidelines for conscious sedation and monitoring during gastrointestinal endoscopy Gastrointest Endosc 2003 Sep;58(3):317-22

3. Evaluation • History, physical examination, review of current medications and allergies, and assessment of cardiopulmonary status • Monitoring of heart rate, blood pressure, respiratory rate, and oxygen saturation • Continuous electrocardiogram (EKG) if indicated • Capnography and bispectral monitoring were considered but not recommended for routine use

4. Medications • The choice of sedative is largely operator dependent • Benzodiazepines used either alone or in combination with an opiate • Favor midazolam for its fast onset of action, short duration of action, and high amnestic properties compared to diazepam • Fentanyl has a rapid onset of action and clearance and reduced incidence of nausea compared to meperidine • Specific antagonists of opiates (naloxone) and benzodiazepines (flumazenil) are available and should be present

5. Benzodiazepinescan induce relaxation and cooperation and often provide an amnestic response • Opiates increases pain threshold, alters pain reception, and inhibits ascending pain pathways • Droperidolproduces an anti-emetic and anti-anxiety effect. It also has mild sedative and alpha-adrenergic inhibitory action • The routine use of flumazenilhas been shown to be associated with quicker awakening and reversal of amnesia, without an increased risk of resedation compared to placebo

6. Combinations of benzodiazepineand opioidagents may increase the risk of desaturation and cardiorespiratory complications • Midazolam causes anterograde amnesia. Paradoxical reactions, including hyperactive or aggressive behavior have been reported • Acute withdrawal, including seizures, may be precipitated after administration of flumazenilto patients receiving long-term benzodiazepine • Naloxoneshould be used with caution in elderly individuals and those with cardiac diseases • All narcotic agentsmust be used cautiously in patients taking other central nervous system depressants, such as other narcotic agents, sedatives, tranquilizers, phenothiazines and antihistamines

7. Pharyngeal anesthesia • Using topical anesthetics to suppress the gag reflex during procedures, including benzocaine, tetracaine, and lidocaine • Administered by aerosol spray or gargling, the effects last for up to one hour • Numerous case reports on the occurrence of methemoglobinemia after administration of topical anesthetics • Clinical "cyanosis" in the face of a normal arterial partial pressure of oxygen; pulse oximetry is inaccurate in the presence of methemoglobinemia • The treatment of methemoglobinemia is with intravenous methylene blue

8. No sedation • Ultrathin endoscopes with diameter from 5.3 to 6 mm • The same regions of the upper digestive tract; permit the passage of pediatric biopsy forceps to obtain tissue samples • Comparable or improved comfort compared to standard sedated peroral upper endoscopy • Less sensitive than standard endoscopes for detecting lesions • Older patients, men, patients who are not anxious, or patients without a history of abdominal pain may have better tolerance

9. Deep sedation or general anesthesia • Patients undergoing prolonged therapeutic procedures • Complex procedures such as endoscopic retrograde cholangiopancreatograph (ERCP) • Propofol has been demonstrated to be superior to standard benzodiazepine / narcotic sedation • Requires more intensive monitoring by trained individuals

10. Sedation-related risk factors • Extremes of age • Severe pulmonary, cardiac, renal or hepatic disease • Pregnancy • The abuse of drugs or alcohol • Uncooperative patients • A potentially difficult airway for intubation

11. ASA stated difficult airway • Patients with previous problems with anesthesia or sedation • Patients with a history of stridor, snoring, or sleep apnea • Patients with dysmorphic facial features, such as Pierre-Robin syndrome or trisomy-21 • Patients with oral abnormalities, such as a small opening (<3 cm in an adult); edentulous; protruding incisors; loose or capped teeth; high, arched palate; macroglossia; tonsillar hypertrophy; or a non-visible uvula

12. ASA stated difficult airway • Patients with neck abnormalities, such as obesity involving the neck and facial structures, short neck, limited neck extension, decreased hyoid-mental distance (<3 cm in an adult), neck mass, cervical spine disease or trauma, tracheal deviation, or advanced rheumatoid arthritis • Patients with jaw abnormalities, such as micrognathia, retrognathia, trismus,or significant malocclusion.

13. ASA guidelines • The presence of one or more sedation-related risk factors, coupled with the potential for deep sedation, will increase the sedation-related events • In this situation, an anesthesiologist should be consulted • The routine assistance of an anesthesiologist for average risk patients undergoing standard upper and lower endoscopic procedures is not warranted and is cost-prohibitive.

14. Summary • A focused history and physical is required prior to the administartion of moderate sedation • Routine monitoring of the patient's pulse rate, blood pressure, oxygen saturation, are useful identifying early problems. Monitoring of EKG recordings may be helpful in selected cases. Capnography, measurement of carbon dioxide retention, may be useful in prolonged cases. • The use of benzodiazepines and/or opiates will result in a satisfactory outcome in nearly all patients. Endoscopists prefer the combination of these drugs, but it adds little benefit from the patient's viewpoint. • Specific antagonists of opiates (naloxone) and benzodiazepines (flumazenil) are available and should be present in every endoscopy unit to treat oversedated patients

15. Optimal propofol plasma concentration during upper gastrointestinal endoscopy in young,middle-aged, and elderly patients Anesthesiology 2000; 93:662–9

16. Background • Outpatient gastrointestinal endoscopy necessitates reliable sedation involving rapid onset, short predictable duration of action, and rapid elimination without side effects • Propofol has increasingly become the drug of choice for maintaining adequate sedation during monitored anesthesia care • Suitable propofol plasma concentrations during gastroscopy have not been determined for suppressing somatic and hemodynamic responses in different age groups

17. Methods • Three groups of 23 patients each, aged 17–49 yr (group 1), 50–69 yr (group 2), and 70–89 yr (group 3), who were undergoing elective outpatient upper gastrointestinal endoscopy • Pharmacokinetic model-driven infusion device designed for computer-assisted continuous infusion • Randomized to receive predetermined target concentrations of propofol ranging from 0.25 to 4.0 µg/ml, maintained for 15 min before verbal command and insertion of an endoscope

18. Methods • Plasma propofol concentration in which 50% of patients do not respond to these different stimuli were determined by logistic regression: • verbal command (Cp50ls) • somatic response to gastroscopy (Cp50endo) • gag response to gastroscopy (Cp50gag) • Hemodynamic responseswere also investigated in the different age groups

19. Results • Cp50ls concentrations were 2.23 µg/ml (group 1),1.75 µg/ml (group 2), and 1.40 µg/ml (group 3). • The Cp50endo values in groups 1 and 2 were 2.87 and 2.34 µg/ml, respectively, which were significantly higher than their respective Cp50ls values • Cp50endo value in group 3 was 1.64 µg/ml, which was close to its Cp50ls value • Because of a high degree of interpatient variability, Cp50gag could not be defined • Systolic blood pressure response decreased with increasing propofol concentrations

20. Conclusions • Both Cp50ls and Cp50endo decreased significantly in the elderly patients • Cp50ls was significantly lower than Cp50endo in 17- to 69-yr-old patients conscious sedation may be inappropriate for gastroscopy in patients within this age range • In patients aged 70-89 yr, the Cp50ls value was close to the Cp50endo value. That means conscious sedation can be performed easily in these patients

21. Conclusions • Cp50ls and Cp50endo decreased significantly as age increased. • To suppress the somatic response to gastroscope insertion in young and middle aged patients, higher plasma propofol concentration than the Cp50ls value is necessary • In elderly patients, the plasma propofol concentration for Cp50ls is sufficient to suppress somatic response during insertion of a gastroscope • SBP response on gastroscope insertion decreased with increasing propofol plasma concentration • SBP response in elderly patients was higher than that in young and middle-aged patients

22. Patient feedback in sedation and anesthesia Professor and Head of Department, Glasgow University Department of Anaesthesia

23. Ideal sedative technique • Rapid and smooth onset of action with easy control of the level and duration of sedation • Wide therapeutic ratio with minimal cardio-respiratory depression • Allow the patients to recover rapidly full consciousness without rebound or emergence effects • Benzodiazepines tend to have prolonged duration of action and even Midazolam • The pharmacokinetic properties and the recovery characteristics of Propofol have encouraged its use for sedation

24. Sedation with Target-Controlled Infusions • The first use of TCI for sedation using Propofol was reported in 1991 • 20 patients with a mean age of 52 years undergoing upper gastrointestinal endoscopy. The median blood concentration of Propofol for insertion of the endoscope was 2.5 µg/ml (range 1.5 to 4.0 µg/ml) • Conditions for endoscopy were good in 15 patients and fair in the remaining 5. Patient co-operation was good in 16 patients and fair in 4 • There was a significant reduction in SpO2 during the procedure from a mean of 94.2% to 89.3%

25. Sedation with Target-Controlled Infusions • Satisfactory sedation was reported with TCI Propofol in patients undergoing orthopaedic procedures under regional blockade • The median blood Propofol concentration required was 0.93 µg/ml (range 0.15 to 2.63 µg/ml) • The patients spent 88% of the time at a satisfactory level of sedation with sedation scores of 3 or 4 • Undesirable oversedation occurred for an average of 2.5% of the total time and was quickly reversed by selecting a lower target concentration

26. Patient-Controlled Sedation • Patient-controlled analgesia (PCA) is a well-recognised technique for pain control and patient-controlled sedation (PCS) has been described as a valuable technique for sedation • A device similar to a PCA system to self-administer single doses of a sedative • In most of the studies which have compared patient-controlled sedation using Propofol or Midazolam • Propofol has been reported to produce a more rapid onset of sedation with faster return to normal following the procedure

27. Patient-Maintained Sedation • Patient-maintained sedation (PMS) allows the patient to control the target concentration of Propofol using a button push • The efficacy and safety PMS was assessed in 20 patients scheduled to undergo day case surgery • A target-controlled infusion of Propofol was started at 1 µg/ml and the patient allowed to increase the target by 0.2 µg/ml by operating a control button • Lockout time of 2 minutes and a maximum target concentration allowed of 3 µg/ml

28. Patient-Maintained Sedation • Highly significant reductions in anxiety scores from presedation levels at 15 minutes post sedation which were remained low until induction • Median target concentration of propofol varied from 1.0-1.2 µg/ml • No patients became oversedated and all remained cardiovascularily stable. • Two older patients required low dose supplementary oxygen for mild arterial oxygen desaturation but there were no instances of airway obstruction • Patient satisfaction with the system was high

29. Patient maintained sedation Anaesthesia 2004Feb; 59(2) 127-132(6)

30. Evaluating safety and recovery using a patient maintained, target controlled infusion of propofol for sedation in 20 patients undergoing colonoscopy • Using a handset with a two-minute lockout interval, patients could make 0.2 µg/ml increments to an initial target plasma concentration of 1 µg/ml up to a maximum 4.5 µg/ml • Four patients became oversedated but required no airway or circulatory interventions • Subjects had a significant reduction in heart rate and in systolic blood pressure

31. Choice reaction time testing 15 min after colonoscopy showed a significant median rise of 162 ms (p < 0.05). Six patients had faster reaction times post-colonoscopy • All patients denied unpleasant recall and were satisfied with the system • Although over-sedation was a problem in this model, we conclude that patient maintained propofol sedation could be possible for colonoscopy

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