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Nitrous oxide inhalational sedation
- 1. 1 Pharmacological considerations in the child patient Dr.Sucheta Prabhu Second year PG 14/12/17
- 2. Questions asked previously Short essays Drug dosage calculation in children Conscious sedation Use of midazolam in management of children Long essays Conscious sedation in pediatric dentistry Hospital management in pediatric dentistry 2
- 3. How does a child differ from adults? 3
- 4. Systems of the body differing4 Low acidity in infants Lowered secretion of gastric acid Low concentration of bile acids,lipase Infants and young children are relatively deficient in liver enzymes At risk for toxicity if not dosed correctly Vast majority of drugs excreted via renal system. Immature renal capacity hampers excretion.
- 6. Drug Dosages6 • Dilling’s rule • Gabius’s rule • Bastedo’s rule • Catzel’s rule • Ausberger’s rule
- 7. Major reasons for use of drugs in children Pain & anxiety Infections Others 7
- 8. Pain Anxiety 8 Direct response to an aversive stimulus Unpleasant feeling/worry that something unpleasant might happen Childrens’s response to pain is influenced by age,memory of previous negative dental experience, and coping ability.
- 9. Recognition of anxiety Increased blood pressure and heart rate Trembling Excessive sweating Dilated pupils 9
- 10. Sedating children can be unpredictable. 10
- 11. Guidelines & Evidence Unable to determine which drug was most effective. Many cases have used other physical restraints with nitrous oxide (30- 50%). 11
- 12. Clinical decision making Age Degree of surgical trauma involved Current medical condition Allergies Physical status Airway patency Psychologic status 12
- 13. Medical status13 ASA Class Patient description I Normal , healthy patient without underlying systemic disorder II Patient with mild systemic disease III Patient with severe systemic disease, which limits his/her activity but is not life threatening IV Patient with severe systemic disease, which limits his/her activity that is constantly life threatening V Moribund patient, who is not expected to survive beyond 24 hours with /without operation VI Brain dead patient whose organs may be harvested for transplant E Emergency patient Grades I-IV €
- 14. Terminologies General anesthesia: Elimination of all sensation accompanied by loss of consciousness. Analgesia: Diminution/elimination of pain in the conscious patient Deep sedation : A controlled ,pharmacologically induced state of depressed consciousness that retains the patients ability to independently and continuously maintain airway and respond appropriately to physical stimulation and verbal command that is produced. 14
- 15. Terminologies Dissociative anesthesia: Dissociative anesthesia is a form of anesthesia characterized by catalepsy, catatonia, analgesia, and amnesia. It does not necessarily involve loss of consciousness and thus does not always imply a state of general anesthesia. Neuroleptic anesthesia : An intense analgesic and amnesic state produced by administration of narcotic and neuroleptic drugs; unconsciousness may occur, and cardiorespiratory function may be altered. Relative analgesia: Used to describe a state of altered consciousness in which a person is more carefree and relaxed. Other terms : Chemamnesia, Sedamnesia,Twilight sleep,Comedication. 15
- 16. Conscious A patient is said to be conscious if he is capable of rational response to command and if he has all his protective reflexes intact, including the ability to maintain and clear his airway in a patent state. 16 American Association of Anesthesiology
- 17. Conscious sedation A medically controlled state of depressed consciousness that allows protective reflexes to be maintained , retains the patients ability to maintain a patent airway independently and continuously, and appropriate response by the patient to physical or verbal command. 17
- 18. Objectives Alter patients mood,making him psychologically acceptant. Must allow to maintain consciousness throughout the procedure. Must result in patient cooperation. Should raise pain threshold. Must allow protective reflexes to be intact. Should produce only small variation in vitals. 18
- 19. Indications Dental Anxiety Medical,physical,cognitive disability Involuntary movement conditions 19
- 20. Clinical guidelines for use of conscious sedation Patient evaluation (ASA) Informed consent Monitor baseline vitals Preoperative dietary restrictions Written instructions to caregiver One additional personnel trained in BLS 20
- 21. Appropriate intake of food and liquids before elective sedation Ingested mateial NBM Clear liquids, clear tea, black coffee 2 hrs Breast milk 4 Non human milk 6 Light meal : Toast + clear liquids 6 21
- 22. Preparation & Setup of procedures S= Suction O=Oxygen supply A=Airway P=Pharmacy M=Monitors E=Special equipment for a particular use 22
- 23. Routes of administration • Easy to administer • Easy to monitor • Level of sedation can not be easily changed Oral • Non invasive • Drugs have very rapid onset • Short recovery period Inhalational Parenteral 23 • Intravenous • Intramuscular • Subcutaneous
- 24. Oral sedation Advantages Ease of administration Low cost Decreased adverse reactions No specialised training Disadvantages Patient compliance needed Prolonged latent period Inability to titrate Unpredictable action duration 24
- 25. Factors influencing drug absorbtion Lipid solubility pH of gastric tissues Mucosal surface area Gastric emptying time Dosage form of drug Drug inactivation Presence of food in stomach 25
- 26. Drugs used for preoperative anxiolysis Ethyl alcohol Barbiturates Benzodiazepines Non benzodiazepine anxiolytics Chloral derivatives 26
- 27. Oral barbiturates • 16-24hr CNS depression • Phenobarbital • Sleeping pills Long acting • 3-4 hour duration • Pentobarbital • Insomnia Short acting • Thiopental • Methohexital Ultrashort acting 27 Disadvantage: Addictive, develop tolerance,implicated in suicide attempts
- 28. Benzodiazepines Flurazepam Diazepam Lorazepam Midazolam Prefered in management of preoperative anxiety . Advantage: Safety over other sedative- hypnotics 28
- 29. Chloral hydrate Popularly used in pediatric dentistry earlier Produces GI irritation. No analgesic properties. Oral dose 50 mg/kg Half life 7-9.5 hours. Rapid onset drowsy sleep within 30-45 minutes. Diration of action is 2-5 hours 29
- 30. H1 Histamine Blockers(Antihistamines) Promethazine Phenothiazine Decreased agitation,hyperactivity Antihistaminic,Antiemetic,sedative property Does not cause unconsciousness in large doses Does not depress respiratory , cardiovascular system. Adverse effect-Drying of mouth,blurred vision Dose: 12.5-25 mg 1 hour prior 30
- 31. Rationale for use Reduce anxiety prior to dental appointment To be taken 1 hour HS Not advocated for deep level of sedation since its not controllable. Thorough knowledge of adverse effects a must. 31
- 32. Rectal sedation Advantages Rapid onset Non invasive Low cost Disadvantages Does not bypass the hepatic first pass effect Lack of control 32
- 33. Drugs in rectal sedation Barbiturates Opiods Promethazine Chloral hydrate Benzodiazepines Ketamine Lytic cocktail (Meperidine+Promethazine+Chlorpromazine) 33
- 34. Sublingual , Intranasal sedation Drug enters directly into systemic circulation avoiding first pass effect Patient cooperation is important. Drugs Opiods , sedatives Oral submucosal fentanyl citrate (fentanyl lollipop) Midazolam(0.2-0.4 mg/kg) and sufentanil (spray) Can be used when speed is of essence 34
- 35. Intramuscular sedation Advantages Rapid onset Maximal clinical effect in 30 mins More reliable absorbtion Patient cooperation not essential Disadvantages Inability to titrate Inability to reverse action Prolonged duration of drug effect Painful injection 35
- 36. Recommendation & Sites Adult patient when inhalation and iv unavailable Distuptive patient where other routes proved ineffective Route to administer emergency drugs 36
- 37. Drugs Anti anxiety and sedative hypnotics Antihistamines Barbiturates Opiod analgesics Dissociative Anesthetic NSAID (ketorolac, diclo) Complications: Nerve damage, intraarterial injection 37
- 38. Nitrous oxide 1772 Joseph Priestley 1844 Horace Wells 1872 Edmund andrews 20% O2 80% N2O 1960 Harold Langa into dentistry 38 Over 160 years of use with safety
- 39. Advantages Viable & cost effective Peak & depth control (titrated) Rapid induction & recovery Minimal effect on CVS, Respiratory, laryngeal reflex Limitations Nausea(acute) Impotence,liver toxicity, abuse(chronic) Degree of cooperation from patients Bullky equipment 39
- 40. 40 Indications Mild-moderate anxiety Needle phobia Gag reflex Contraindications Very young children Underlying psychiatric disorders
- 41. Nitrous oxide sedation Inhalational Most frequently used CNS: Depressant and Euphoriant Concentration effect 41 Sweet smelling Colourless Non-inflammable Inert gas Blood gas coefficient 0.47 Rapid onset & recovery Weak analgesic MAC 110
- 42. Guedel’s stages of anesthesia42
- 43. Equipment43 Free standing unit Piped inhalational system Unit head Reservoir bag Gas delivery system Safety Features Minimum O2 is 30% Automatic gas cutout Color coding Gas pressure dials Scavenging, Alarm
- 44. Precautions Efficient scavenging system required. Laminar air flow recommended. Nasal hood may have an unacceptable odors so flavored liquid may be applied. Diffusion hypoxia may occur as the sedation is reversed at the termination of the procedure. 44
- 45. Procedure Bag is filled with 100% O2 & delivered 2-3 mins Slowly introduce nitrous oxide Adjust concentration to 30% nitrous & 70% O2 Post procedure administer 100% O2 for 5 mins 45
- 46. Monitoring during sedation Respiratory rate,depth Pulse Responsiveness Body temperature 46
- 47. Signs & symptoms of optimal sedation Symptoms • Lightheadedness • Tingling • Wave of warmth • Numbness • Euphoria • Lightness/Heaviness in extremities • Analgesia Signs • BP,HR slight elevation early on, return to baseline. • Respiration smooth • Flushing of face, extremities • Decreased muscle tone 47
- 48. Clinical indicators of over sedation Patient persistently closes mouth Spontaneous mouth breathing Complains of nausea Fails to respond rationally , gives sluggish response Becomes sleepy Speaks incoherently or dreams Becomes uncooperative 48
- 49. Recovery & Discharge CVS function & Airway patency are satisfactory and stable Presedation level responsiveness established State of hydration adequate 49
- 50. Psychomotor effects Bender Visual Motor Gestalt test Determines visiomotor capacity of child 50
- 51. Instructions to parents Any change in health to be reported within 7 days before treatment . Seek advice if vomiting persists , temperature is elevated beyond 24 hours 51
- 52. Special indications for Nitrous oxide sedation Cardiovascular disease Can minimise risk of MI Cerebrovascular disease Stress/anxiety reduction Heaptic disease No hepatic biotransformation, can be safely used . Epilepsy& seizure Useful to avoid stress 52 Brown DM. Aiding in administration of nitrous oxide analgesia.Idaho state board of dentistry 2005
- 53. Issues surrounding nitrous oxide Potential biohazard from long term exposure to trace anesthetic gas. Scavenging nasal hood a must Monitoring of trace nitrous oxide Recreational abuse 53
- 54. Intravenous sedation William Harvey(1578) Pierre ore chloral hydrate iv(1872) Emil fisher : Barbiturates(1900) Neils jorgenson(1945) 54
- 55. Intravenous sedation agents Indications Mostly adults Traumatic surgical procedures Contraindications Allergies Impaired renal/hepatic systems 55 Children below 16 years to be cautiously approached
- 56. Advantage Rapid onset Titration possible Recovery period short Motor disturbances less Disadvantage Venipuncture needed More intensive monitoring Recovery not complete Most agents cannot be reversed 56
- 57. Drugs used for intravenous sedation Benzodiazepines : Diazepam Midazolam Propofol 57
- 58. Benzodiazepines Discovered in Switzerland by Hoffman-La Roche 58 Clinical effects 1.Induction of conscious sedation for 20-30mins. 2.Anterograde amnesia 3.Muscle relaxation 4.Anticonvulsant action 5.Minimal CVS & RS depression when titrated slowly. Side effects 1.Respiratory depression 2.Cardiovascular depression 3.Tolerance
- 59. Diazepam/Lorazepam First BZD used in intravenous sedation practice Almost insoluble in water Metabolised in liver, eliminated via kidneys Half life =43 hours Dose=0.1-0.2 mg/kg Limitation: Long recovery period 59
- 60. Midazolam Agent of choice for iv sedation in dentistry. Acute detachment, retrograde amnesia Lipid soluble, readily penetrates BBB Half life 1.9 hours Rapid action, more potent Dose 0.07-0.1 mg/kg Slight cardiovascular,respiratory depression Angry child syndrome (paradoxic increased aggression) 60
- 61. Propofol 2,6 diisopropylphenol Elimintion half life 30-50 minutes Dose:6-9mg/kg/hr Narrower margin of safety Rapid onset and recovery May have central depressant effects Less residual postoperative “Hangover” 61
- 62. Ketamine Synthesized by Parke-Davis Phencyclidine derivative Causes dissociative analgesia(blank stare) Maintains CVS stability ,muscle tone, airway reflexes Iv dose 1mg/kg May cause increased ICT, tachycardia , postemergence delirium(vivid nightmares) Recreational drug. Chronic use impairs cognitive ability,memory loss. 62
- 66. 66
- 67. Titration of agent 0.5ml (1mg) over 15 secs Pause for 1 minute Followed by 1mg over 1minute till signs visible. 67 Signs Slurred /Slowed speech Relaxed demaneour Delayed response to commands Positive Eve’s sign(Motor coordination) Verril’s sign
- 68. Local complications Extravenous injection Intraarterial injection Postoperative haematoma 68
- 69. Emergency equipment69 oxygen cylinder oral airways nasal airways ambu bag suction equipment
- 71. References 1.Marwah N. Textbook of pediatric dentistry.3rd edn. 2.Tandon S. Textbook of Pedodontics. 2nd edn. Paras medical publishers 2009 3.Malamed S. Sedation :A guide to patient management.4th edn.Mosby 4.Girdler N.M.Clinical sedation in dentistry.Wiley-Blackwell publication 2009 71