NITROUS OXIDE and OXYGEN SEDATION/intro to dental anesthesia – Flashcards
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who was the dentist that attended the grand exhibition?
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horace wells
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who was the 1st person that got his tooth extracted under N2O
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horace wells
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who was the father of anesthesia
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horace well december 11, 1844
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what were the reasons for the inactivity of n2o?
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-unreliable equipment -failure to produce satisfactory results -lack of knowledge
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what year bought the discover of lidocaine?
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1940s
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percentage of general dentists, oral & maxillofacial surgeon, pediatric dentists use N20
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2/3rd general dentists, 90% pediatric dentists 80% oral & maxillofacial surgeons
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N2O is also used in
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podiatry labor & delivery emergency medicine alcohol detoxification programs
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Definition of Pain:
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an unpleasant sensory and emotional experience arising from actual or potential tissue damage
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nociceptors is?
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Pain receptors
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Impulses are altered along the way by an
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endogenous opioid system
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Exogenous morphine binds to what receptor
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opiate receptor
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analgesia
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reduce or relieve pain
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reduce or relieve pain
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analgesia
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nonspecific feeling of apprehension, worry, or uneasiness, the source of which may be vague or unknown is called
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aniexty
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aniexty
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nonspecific feeling of apprehension, worry, or uneasiness, the source of which may be vague or unknown
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normal reaction when one's body, lifestyle, values or loved ones are threatened
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(anxiety) Rational reaction
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Rational reaction
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normal reaction when one's body, lifestyle, values or loved ones are threatened
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anxiety may be accompanied by?
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restlessness, tension, tachycardia, dyspnea
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feeling of fright or dread related to an identifiable source recognized by the individual is called?
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fear
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fear
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feeling of fright or dread related to an identifiable source recognized by the individual
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how are pain and fear interrelate?
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as pain increases, anxiety is heightened ? pain becomes enhanced
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any persistent/irrational fear of something specific, object, activity, or situation (excessive & unreasonable) is called
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phobia
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anxiolytics
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medications causing minimal sedation N2O concentration at <50%
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anesthesia
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reversible loss of sensation
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NIOSH
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National institute of safety and health
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if N2O is under pressure what form would it be in? room temp?
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liquid gas
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what is N2O heavier than?
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air
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in the right circumstances, it is nonflammable but supports what?
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combustion
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decomposition in _____ at high temp can be ___
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cylinder explosive
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what are characters that supports combustion?
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A colorless, tasteless, sweet-smelling agent
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when used alone nitrous oxide is******
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-a very weak anesthetic (loss of sensation) -an intense analgesic (altering the perception of pain)
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purpose of nitrous oxide?
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to relax individuals who are mildly apprehensive about the dental experience
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what can N2O provide for Pt
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provides pain control for procedures that are only slightly or moderately painful
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conscious sedation
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the client is always awake and able to respond to verbal commands, breathe automatically, and cough so that aspiration is avoided always under 50%
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the client is always awake and able to respond to verbal commands, breathe automatically, and cough so that aspiration is avoided
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conscious sedation
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inhalation sedation
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the nitrous oxide and oxygen gases are inhaled through the nose anytime sedation is inhaled
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the nitrous oxide and oxygen gases are inhaled through the nose
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inhalation sedation
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nitrous oxide acts on the psyche or the CNS in a way that pain impulses are not relayed to the cerebral cortex or their interpretation is altered
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psycho sedation
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a state of sedation that alters mood and increases the pain reaction threshold, but does not totally block pain sensation
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relative analgesia
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what kind of sedation is in the unconscious stage?
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general anesthesia deep sedation IV sedation
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what kind of sedation is in the conscious stage?
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IM sedation oral sedation local anesthesia hyponosis/biofeedback
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what kind of sedation is in between conscious to unconscious stage?
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inhalation sedation
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what are the 5 ideal sedation for N2O
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-rapid onset -titration-to get to patients level, slowly induced pt to the right level -anxiolytic (anti-anxiety) -analgestic (reduce pain) -rapid & complete recovery- after 5 mins of O2 they are recover
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if it's 50% or less where would that stand?
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anxiolysis- minimal sedation (only in high altitude it would be higher)
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if it's >50% it would lead to?
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moderate sedation- analgesia (reduce pain) deep sedation- analgesia general anesthesia
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analgesia is what type of sedation? at what level
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moderate, >50% deep
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an unpleasant sensory and emotional experience arising from actual or potential tissue damage
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pain
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pain is also in
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fear & anxiety actual damage
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pain threshold is
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inversely proportional to pain reaction high tolerance will not get the reaction easily
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pain reaction can be ___ in the same person at different times
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different
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A ___ pain threshold means the patient will ___ react as quickly to a painful stimulus
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HIGH NOT
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dental fear/anxiety affects ___ of the population
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~3/4
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physiologic, psychological & behaviorial cues
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-increased respirations & heart rate, sweating, etc -flashbacks -wringing hands, crying, laughing etc
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what can lower pain perception?
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behavioral management- anxiety
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how is fear and anxiety measured?
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simple interview with a patient anxiety questionnaire
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signs and symptoms of fear and anxiety
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quiet, withdrawn talkative agitated angry sweaty palms clenched fists twisting of the hair wringing hands faint pale red face breathing hard elevated pulse elevated respiration crying
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causative factors of fear and anxiety
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-in-experience -past medical or dental experiences -stories -worry about clinician's expertise
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nitrous oxide in what pharmacologic category?
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dental gas general anesthetic
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nitrous oxide is recommended use for
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-mild anxiety and apprehension toward dental procedures -can reduce the likelihood of stresss-related complications in patients with medical complications
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N2O does not effect what?
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heart rate blood pressure liver kidney
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As long as an adequate amount of ____ is delivered concurrently with N2o will not effect heart rate, blood pressure, liver, kidney
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oxygen
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what does N2O effect? normal things that happen
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-analgesia- numb -depersonalization-not worry, happy -dizziness-if so, lower it -euphoria -sound distortion -hallucinations
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what sesations does N2O affect
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-hearing (distant sounds improved, may key into music) -touch -pain(don't perceive in same way) -warmth -(at minimal sedation) reduces the gag reflex, but does not eliminate it
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what does pharmacokinetics mean?
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study of what a body does to a drug
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what are the key factors to pharmacokinetics?
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ADME absorption, distribution, metabolism, elimation
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what is the absorption of N2O?
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lungs-very rapid fat soluble-quickly able to cross membranes really quick absorption
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what is the distribution of N2O?
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-low solubility in blood and tissues- NOT a systemic drug -onset of action 2-5 mins
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what is the onset action (how fast does it distribute into the body) of N2O?
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2-5 mins
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N2o is not what type of drug?
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systemic
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what is the metabolism of N2O?
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<.004% systemic drugs usually occurs in the liver
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where does the systemic drugs eliminate through?
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- usually via urine or feces
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what is percentage of N2O is equal to mg of morphine?
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20% to 15 mg
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what can premedication do?
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it could add possible effect
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whats the physiology of nitrous oxide?
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its a CNS depressant-alters the relay of nerve impulses to the crebral cortex, causing them to be interpreted differently-->reduces anxiety and increases pain tolerance (does not block pain perception)
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what is the only anesthetic not metabolized?
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n2o
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does n2o block pain perception?
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no
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how does n2o depress CNS?
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alters the relay of nerve impulses to the crebral cortex, causing them to be interpreted differently-->reduces anxiety and increases pain tolerance
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what are the stages of anesthesia?
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stage 1- analgesia stage stage 2- delirium or excitement phase stage 3- deep sedation stage 4-general anesthesia with respiratory paralysis
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what is stage I of anesthesia?
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minimal sedation- appropriate for dental hygiene care
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what stage for dental hygiene care
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stage 1 minimal sedation
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what is stage II of anesthesia?
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delirium or excitement phase characterized by hyper-responsiveness to stimuli and loss or consciousness.
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what is the immediate tx of entry into the excitement stage
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increase the % of oxygen to 100% and to turn the n2o off
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what is the desirable characteristics of N2O?
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analgesic-pain killer anxiolytic- anti-anxiety amnestic- loss of memory rapid onset of action titration possible rapid and complete recovery
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whats the indications for use of n2o?
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-mild apprehension -allergy to local anesthetic -refusal of local and general anesthetic -hyper-sensitive gag reflex -cardiac conditions ( decrease stress, increase exposure to more oxygen) -procedures in areas of infection -asthma (actually receives more oxygen) -cerebral palsy- muscular contraction at all time (relaxation) -mental retardation (patient management)
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what is the advantage of n2o?
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-simple relatively safe -good choice for high risk person with cardiovascular disease -equipment simple & requires little maintenance. straps/airways are not required -pt is awake and responsive at all times -rapid onset & recovery -most do not need a driver -no need for lab test or restricted food intake. no need for recovery roome
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what is the disadvantages of N2O?
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-vertigo, nausea or vomiting (if too much nitrous or if the operator fluctuates the levels too much) -pt. with behavior problems cannot always be managed -mask is bulky, may impede instrumentation
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Contraindications for Use of Nitrous Oxide - Respiratory System
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Upper respiratory infections/conditions may result in insufficient amounts of N2O/O2 entering the respiratory system. Patients susceptible to hypoxia because of airway resistance, impaired function, or movement seem to be at a slight risk. Patients with cystic fibrosis may incur bullae (thin walled balloon-like extensions or air sacs) due to the expansive nature of N2O/O2.
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too much nitrous or if the operator fluctuates the levels too much can cause?
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nausea or vomiting
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Upper respiratory infections/conditions may result in
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infection results in insufficient amounts of N2O/O2 entering the respiratory system. hypoxia because of air resistance, impaired function or movement seem to be at a slight risk pt with cystic fibrosis may incur bullae due to the expansive nature of n2o/o2 are not candidate for n2o
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Patients with cystic fibrosis may incur
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bullae (thin walled balloon-like extensions or air sacs) due to the expansive nature of n2o/o2
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is n2o metabolized in the liver
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no
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Contraindications for Use of Nitrous Oxide:Gastrointestinal
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because of the expansive nature of the gas, therefore individuals with a bowel obstruction may experience increasing expansion, pressure & discomfort
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Contraindications for Use of Nitrous Oxide Genitourinary and reproductive systems
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does cross the placental barrier. Necessary to maintain adequate O2 levels to prevent spontaneous abortion. N2O/O2 combination is a commonly used agent in obstetrics. Should be avoided in the first trimester. Obtain appropriate medical consultation.
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what cancer drug contraindicated with n2o? what may it increase?
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-bleomycin sulfate therapy -May increase the incidence of pulmonary fibrosis and other pulmonary diseases.
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why is patient susceptible to hypoxia?
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airway resistance, impaired function or movement seem to be at a slight risk
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patients with cystic fibrosis may incur? why?
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bullae (thin walled balloon-like extensions or air sacs)due to the expansive nature of N2O/O2
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Contraindications for Use of Nitrous Oxide:Middle Ear Disturbances
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nitrous infiltrates the rigid, noncompliant area of the middle ear increasing pressure and is therefore contraindicated
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Eye Surgery contraindicated Contraindications for Use of Nitrous Oxide:
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- Nitrous could expand the "gas bubble" in recent ophthalmic surgery & is therefore contraindicated
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Contraindications for Use of Nitrous Oxide: psychotropic drugs
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-will alter with conditions Synergistic affect in patients taking antidepressants or other
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Contraindications for Use of Nitrous Oxide: Cancer
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- contraindicated in patients receiving bleomycin sulfate therapy (cancer drug) used in the treatment of lymphomas, testicular tumors and squamous cell carcinoma
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Contraindications for Use of Nitrous Oxide:Drugs used to induce sleep or that list drowsiness as a side effect
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may enhance drug effects
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relative contraindications
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pregnancy (1st trimester) communication difficulty currect or recovering from drug addiction nasal obstruction (cold, allergy) emotional instability epilepsy (may trigger seizures)
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cont. relative contraindications
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Negative past experience Fear of nitrous oxide sedation (compulsive personalities who must be in control) Chronic Obstructive Pulmonary Disease (COPD) Emphysema & Chronic Bronchitis Middle ear disturbances Surgical procedures such tympanic membrane graft, infection Recent ophthalmic surgery (gas bubble placement) Patients receiving bleomycin (cancer agent)
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Absolute Contraindications
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COPD (ASA IV) Pneumothorax Recent retinal therapy Cystic fibrosis Respiratory obstruction ASA III upwards Traumatic brain injury Patients with bowel obstruction Patients taking Kava Kava
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The Dangers of Nitrous Oxide Use and Abuse
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1. Oxygen deprivation of the brain. 2. Diffusion hypoxia-- not getting enough O2 3. Bone marrow suppression- red/white cell production 4. Decreased fertility 5. Liver and kidney disease 6. Peripheral neuropathy- dont have the correct feelings, leg, hands 7. Mixture of N2O / O2 is flammable
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Signs & Symptoms of Appropriate Minimal Sedation
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-Patient is aware of surroundings -Patient responds to directions & conversation -Protective cough & gag reflexes remain intact -Lessened pain awareness -Eyes become less active & glazed look appears
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Pt may experience with Appropriate Minimal Sedation
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Tingling Heaviness Body warmth Light feeling; floating Vasodilation in face & neck
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Signs & Symptoms of Oversedation
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-Detachment or disassociation from environment -Dreaming, hallucinating, fantasizing -Out-of-body experiences -Floating +/or flying -Inability to move, communicate, or keep mouth open -Humming or vibrating sound that may worsen
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20 - 40%
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-Numbness tongue, hands, feet, thighs -Hearing is distant -Disassociation, sleepiness, analgesia, euphoria -Body feels either heavy or light
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30 - 50%
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Sweating Nausea Amnesia Increased sleepiness
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40 - 60%
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Laughing, giddiness, dreaming Increased nausea, possible vomiting
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> 50%
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Light general anesthesia onwards
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Pt may experience with oversedation
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-Drowsiness -Dizziness -Nausea -Lightheadedness -Fixed eyes -Body warmth
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Pt may progress to if oversedated
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-Sluggish, delayed response -Slurred words -Agitation/combativeness -Vomiting -Unconsciousness
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potential complications
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diffusion hypoxia (headache, grogginess, "hung-over" -head injury during expectoration -nausea & vomiting (fluctuating levels back and forth) avoid large meals at least 3 hr prior -corneal irritation (leakage of gas can dry eyes- bewared of contacts -behavior problems (cry/fight & flight/amorous behavior at concentrations greater than 50%) -airway obstruction repeated closing of the mouth (too much nitrous oxide) -rigid mandible (too much nitrous oxide) -reluctance to awaken -emotional reaction -excessive perspiration
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adverse effects
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Decreased myocardial contractility Increased cerebral blood flow Increased intracranial pressure Increased pulmonary artery pressure Expansion of spaces that contain air (sinuses,ears) Sexual fantasies
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over-sedation of nitrous oxide results in?
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Hypoxia: lack of oxygen to the tissues -Characterized by headache and nausea -As a result of receiving too much nitrous oxide and a lack of subsequent oxygenation period -Bone marrow depression and white blood cell depression have been reported after prolonged administration of 2-4 days
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N2O has been implicated in the interference of the
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vitamin B12-dependent enzyme methionine synthase in high concentrations or long exposure -Enzyme necessary for DNA synthesis & erythrocyte production
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N2O can be used safely with the following conditions
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Anemia Methemoglobinemia Sickle-cell anemia Leukemia Hemophilia
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Approximately 90% of N2O produced is used
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health settings
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Remaining users include
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-the chemical industry which uses N2O in the production of sodium azide, the explosive agent that inflates an automobile air bag -the racing industry to increase engine performance
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U.S. Department of Transportation (DOT) regulates
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the transportation of the gas.
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Compressed Gas Association (DGA) & Gases and Welding Association (GAWDA) has
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guidelines for the sales and security of nitrous.
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Regulators
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Reduces gas pressure before it is delivered into the tubing
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Flow Meters
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Identifies amount of gas being delivered in liters of flow per minute Adult 6-7 liters/minute Average child=3-5 liters/min
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how liters is given to adult
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6-7 liters/min
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how many liters is given to average child?
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3-5 liters/min
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Reservoir Bag
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Provides additional gas Monitor patient's breathing Assists in emergency
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Conduction Tubing
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Delivers gas to the nasal hood
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Nasal Hood
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Breathing apparatus Ability to sterilize or disposable w/scavenging apparatus
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Nitrous Oxide is stored in a (color)?
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blue compressed-gas cylinder
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in what type of tank is n2o stored in?
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compressed-gas cylinder
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As long as____ of the liquid nitrous oxide is present in the cylinder to convert to the gaseous state, the reading on the pressure gauge of ___ remains constant (usually ~ 750)
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20% 659-900
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Properties of Nitrous Available in pressurized cylinders as a
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liquid (750 psi)
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Oxygen Full tank reads
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2100 psi
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HOWEVER, the pressure gauge drops once there is ____. The gauge is___ representative of the actual amount present
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;20% NOT
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oxygen is stored in?
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green compressed-gas cylinder
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Properties of O2
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Odorless, colorless, tasteless 21% of Earth's atmosphere Human body is 61% oxygen Water is 90% oxygen Oxygen is a required component of N2O when used for sedation
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TIDAL VOLUME
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the lung volume representing the normal volume of air displaced between normal inspiration and expiration when extra effort is not applied must have to before giving O2
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BASELINE
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the ideal minimal amount of nitrous oxide with oxygen needed to relax the client
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properties of o2
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Odorless, colorless, tasteless 21% of Earth's atmosphere Human body is 61% oxygen Water is 90% oxygen Oxygen is a required component of N2O when used for sedation
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Reactions to watch for (turn down nitrous oxide)
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Feelings of heaviness in the chest Spinning or vibration Client does not respond to questioning
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Contaminated nitrous oxide cylinders can contain and produce?
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nitrogen dioxide and may produce nitric acid with serious consequences with a patient
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Calculations
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Divide the flow rate of a specific gas by the tidal volume and multiply by 100 Example: Tidal volume is 7 Oxygen is 5 L/min Nitrous is 2 L/min 2 divided by 7 = 29% nitrous oxide
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HAZARDS TO PERSONNEL(from chronic exposure)
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-Decreased fertility, spontaneous abortion -Birth defects -Bone marrow depression -Anemia- results from bonemarrow depression -Hepatic and renal diseases -Cancer -Oxygen deprivation of the brain -Diffusion hypoxia -Peripheral neuropathy
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N2O Health Provider Risks
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Regulations under the National Institute of Occupational Safety and Health -A leak or unexpected release of compressed nitrous oxide can result in an immediate and severe burn -Chronic exposure to nitrous oxide Not using scavenging equipment Not maintaining equipment
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N2O Health Provider Risks Regulations under the
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National Institute of Occupational Safety and Health
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A leak or unexpected release of compressed nitrous oxide can result
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in an immediate and severe burn
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Chronic exposure to nitrous oxide is from?
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-Not using scavenging equipment -Not maintaining equipment
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Methods to Reduce Concentrations of n2o to health provider (from 900 ppm to 30 ppm)
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-Scavenging system -Fitting the nasal mask -Discouraging client conversation ; mouth breathing -Using a fan to direct nitrous oxide away from the operator -Maintaining the equipment, test for leakage and inspecting the connectors -Monitor with a Nitrous oxide badge -Opening a window (air circulation) -Limiting duration of nitrous oxide use Shutting off and securing the equipment at the end of each day. Check equipment regularly.
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Patient Preparation Ingested Material
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-Informed consent Treatment plan -Preprocedural fasting guidelines
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Ingested Material Minimal fasting period Light meals
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6 hours
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TECHNIQUE / ADMINISTRATION
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1. Prepare the portable gas delivery system and related armamentaria before seating the client 2. Open gas cylinder valves and check pressure levels 3. Confirm scavenging system to be functioning 4. Seat the patient; check medical history, blood pressure and pulse 5. Explain the procedure, describe possible sensations, risks ; benefits, obtain consent 6. Activate O2 flow - Fill reservoir bag 2/3 full by use of O2 flush 7. Have client seat the nose mask and adjust it so it is comfortable (provider confirms mask is adequately seated) 8. Establish TV L/min (ask pt if he/she can breathe comfortably through nose) 9. Introduce nitrous oxide in increments of .5-1L/min and reduce O2 by a corresponding amount 10. Continue to add nitrous oxide at 60 sec. intervals until a baseline level is established (titration) 11. Determine client's baseline level using subjective symptoms and objective signs 12. Monitor client and reassure as necessary 13. When baseline is achieved, proceed with care (for dental care ? 50%) 14. Near the end of the appointment to begin recovery (during polishing) discontinue the nitrous oxide and deliver 100% oxygen 15. Oxygenate 5 minutes for every 15 minutes of exposure to nitrous oxide or until patient recovers 16. Remove the nose mask and slowly bring the client to an upright position 17. When the client feels normal, take vital signs and dismiss the patient 18. Document in the patient's chart
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If nausea, sleepiness, dreaming, vertigo, repeated closing of mouth, a rigid mandible, or restlessness is observed
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REDUCE the % of nitrous oxide to lighten the level of sedation
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Recovery from Nitrous Oxide/Oxygen
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Recover from nitrous oxide/oxygen sedation is the mirror image of induction The same principles that determine the rapid onset of effect also facilitate a rapid recovery Gas must move from: brain?blood?pulmonary alveoli?scavenger system Assessment of recovery (pt can be dismissed without an escort) Engage patient in active dialogue Post-sedation vital signs Evaluate psychomotor skills
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N2O/O2 Administration Technique using Titration
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Begin with approximately 10% - 15% or about 1-1.5 L of N2O in increments of 5%- 10% (0.5-1.0 L) every 1 to 3 minutes until sedation becomes apparent. Wait longer between increments when desired level of sedation is near. This prevents oversedation and maximizes patient comfort.
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N2O Calculations
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Percentage of Nitrous Oxide %N2O = L/min N2O ÷ Total flow (Total flow = L/min O2 + L/min N2O) Example: %N2O = 2 L/min N2O ÷ (4 L/min O2 + 2 L/min N2O) = 2 ÷ 6 = 33%
