MDDr. Michaela Bartošová, Ph.D
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine, Masaryk University
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 Mixture: 50% N2O (nitrous oxide) and 50% O2 (oxygen)
 N2O was used for the first time 200 years ago
 1880 – pain relief during the birth – administered without oxygen –
asphyxia
 50 years 20. century – mixture 50% N2O with 50% O2
 The part of general anesthesia, pain relief
 Administered by anesthesiologists, non - anestesiologists, after
training also intermediate medical staff
 Extremly mild influence on CNS and cardiovascular system
 Individual effect, influenced by sugestion
 Serious side effects are minimal
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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 Easy and safe application
 It could be administered by non-anesthesiologists and
intermediate medical staff (obstetrics, gastroenterology,
dentistry)
 Minimal occurrence of side effects
 Rapid onset of sedation and analgesia
 Fast psychomotor recovery
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 1772 - Josef Pristley discovered N2O
 1778-1829 – Humprey Davy discovered effect of N2O – laughing
gas, Lachgas, rajský plyn – used for entertainment purposes
 1815 – 1848 – Horace Wells – dentist, he discovered analgesic
effect
 20. century – analgesic for oral surgery
◦ Weak effect on pain relief, high risk of hypoxia, imperfect technical
equipment
◦ Anxiolytic and sedative effects are more important than weak analgesic
effects
 80 % N2O and 20% O2 today 50% N2O with 50% O2
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Minimal effect on EEG and bispectral index (form of EEG
monitoring of sedation depth and anesthesia)
 Increased blood flow to the brain and slightly increased blood
volume in the brain
 Neurological manifestations of chronic exposure only in its
frequent recreational usage in the past (numbness, decreased
activity of tendon reflexes, feelings of electric shocks in the body,
cognitive dysfunction, swelling of mitochondria of neurons and
apoptosis)
 NMDA receptor antagonist
 At concentrations of 10 and 20%, it affects psychomotoric
functions
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Amnestic effect– information are different, anterograde
amnesia, mediated by the interaction of N2O with NMDA
receptors
 Analgesic effect - effect on opioid receptors, its stimulation
releases endogenous opioid peptides - endorphins and
enkephalins.
◦ It corresponds to 15 mg of morphium, max. threshold in 10 minute
◦ Rapid development of tolerance
◦ Significant reduction of sensitivity after application of local anesthetic
 Anesthetic effect - used to accelerate the induction of other
inhalation anesthetics
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 The tolerance to nitrous oxide could be created
◦ The tolerance develops between 10 minutes and 2 hours
◦ Significant differences in acute tolerance - various neurotransmitters are involved
in the transmission of information
◦ The decrease in the density of opioid receptors in individual brain regions is also
important
 Respiratory system - increase in respiratory frequency, slight
reduction in tidal volume, pCO2 unchanged
 Cardiovascular system - slight increase in heart rate, heart rate and
peripheral resistance - slight sympathomimetic effect, release of
catecholamines »increase in blood pressure, heart rate, increased
incidence of cardiac arrhythmias
 Gastrointestinal system - in 50% nausea, vomiting
 Kidneys, liver - does not influence their metabolic activity, can be used
in patients with severe diseases of these organs
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Inhalation from lungs to bloodstream and further to CNS
 Slightly soluble in blood, rapid equalization of alveolar
concentration in the lungs with blood = rapid onset of action,
fast disappearance
 The transport in blood is free, not bound to hemoglobin, it is not
metabolized, excreted by the lungs
 Rapid diffusion into closed body cavities and it could lead to their
expansion (intestinal loops, processus mastoideus,
pneumothorax)
 Oxygen in the lungs is diluted during elimination - temporary
hypoxia, there is no risk of hypoxia with a 50:50 mixture
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Feeling of intoxication, vertigo, paresthesia in the upper and
lower limbs, in the oral cavity, feeling of warm in the body,
feeling of euphoria, analgesia begins
 Blood pressure, heart rate and respiratory rate is rising
 Peripheral vasodilation
 Flush - redness on the face
 Decrease in muscle tone, changes in perception, hyperacusis
 Laugh or crying
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Surgical procedures (joint reposition, insertion and removal of drains, abscess incision,
fracture reposition, treatment of wounds and contusions)
 Gynecology and obstetrics - minor gynecological procedures and the first phase of
childbirth
 Urology
 Dentistry
 Gastroenterology - endoscopic procedures
 Dermatology
 Hematology
 Treatment of pressure ulcers
 Podiatrics
 Psychiatry and psychology
 Radiology
 Neurology
 Sick patients in the terminal phase
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Pneumothorax, pneumopericardium, severe emphysema, air embolism, COPD
 Acute myocardial infarction
 After intracutaneous gas injections
 Dilatation of the digestive tract - ileus
 Heart failure, cardiac dysfunction
 Increased intracranial pressure
 With reduced consciousness and lack of cooperation
 Untreated vitamin B12 or folic acid deficiency
 In case of facial injuries disables the usage of an breathable valve
 Ear surgery (tympanoplasty)
 Intraocular gas injections or perforating eye injuries
 Damage to the blood-brain barrier
 First trimester of pregnancy - interference with the metabolic pathway of vit B =
disruption of DNA synthesis
 Children under 3 years
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Short-term headache
 Vertigo
 Nausea, vomiting
 Inhibition of methionine synthetase interferes with the
metabolism of folic acid and methionine
 Prolonged administration leads to vitamin B12 and folic acid
deficiency - erythropoiesis disorders with the development of
macrocytic anemia, leuko- and thrombo-cytopenia to
agranulocytosis
 Neurotoxic complications - acute funicular myelosis
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 In children in 3-4 years, cooperation is necessary
 Younger child needs higher concentration N2O to reach desired
effect
 The fear leads to flat breathing and decreased tidal volumes,
suggestion and calming of atmosphere is necessary.
 Sometimes it is necessary to interrupt analgosedation and choose
another form of analgesia
 Combinations with various drugs can also be performed under the
supervision of an anesthesiologist:
◦ Surface anesthesia
◦ Combination with paracetamol rectally, orally and intravenously
◦ Tramadol - orally
◦ Nalbuphine - intravenously
◦ Midazolam - orally, rectally or intravenously
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Anxiolytic and narcotic (euphoric) effect is applied, pain
reduction with LA application
 Inhalation is accompanied by soothing speech, inducing a
feeling of confidence
 N2O makes the patient accessible to suggestion
 Instructions:
◦ Inhalation before treatment
◦ Application of LA
◦ Inhalation before dental treatment
 Inhalation is also possible with a nasal mask - lower efficiency
 Not suitable for patients with odontophobia
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Cooperation is necessary
 Consider combination with midazolam per os, per rectum, or
nasally (supervision by anestesiologist is necessary)
 Amnesia after inhalation is very frequent
 Defensives reflexes are preserved, the child still defends
himself after inhalation, but the patient does not usually
remember the procedure.
 In children younger than 3 years is the effect of N2O
insufficient, general anaesthesia is necessary
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
 Mixture 50% N2O with 50% O2
 It is delivered in gas bottles (5 a
10 l) with LIV valve (Linde
integrated valve)
 The upper part of the bottle is
marked with a white and blue
stripes – mark for a mixture of
oxygen and nitrous oxide
 White cylinder body designation
for medical gas
 Average number of procedures
(lasting about 10 minutes) 20-
40
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
1. Continuous flow controller
with output
2. Active manometer - gas
quantity indicator
3. Shut-off valve
4. Handrail
5. Quick coupling with
blanking plug
6. Technological input for
bottle filling
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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 Valve body with test button
and loop
 Hose for connection to the
bottle
 Inhalation attachment / mask
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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 1. to control the amount of gas
on active manometr, continuous
flow controller is closed
 2. to connect quickcoupler, of
breathing valve Carnét
 3. to open closing valve in the
direction of mark
 4. to check the flow of gas by
the botton Press
 5. The filter and mouthpiece or
mask is put on breathing valve.
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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 We put a white strap on the
patient's hand and insert the
inspiratory valve with the filter and
mouthpiece into the patient's hand
 The patient wraps the mouthpiece
with his mouth and inhales - deep
breaths only through the mouth
and exhalations through the nose
and mouth
 With the inhalation mask you can
inhale through the nose even
through the mouth
 Inhale for at least 1 minute, max
for effect after 2-3 minutes
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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 Close the valve in the directon of the arrow
 Drain the rest of gas from carnét
 Disconnect the valve in place of quickcoupler
 Remove filter with mouthpiece or mask
 Desinfect Carnét
 Patient is waiting in the waiting room for 30 minutes
till the effect of gas will fade.
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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 At a temperature higher than -5ºC
 Out of reach of flammable material
 In well-ventilated rooms
 Do not expose to strong heat
 Move to a safe place if there is a risk of fire
 The bottle must be clean, free of oil or grease
 Stored in areas reserved for the storage of medical gases
 Secure the bottle from falls and punches
 Store and move with closed valves
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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 Contact patient-doctor is necessary – calm speech, suggestion
 Eliminate negative perceptions – loud speech, manipulation with
instruments, we can not hurry, we are quiet
 Patient reacts to your question, he/she is able to cooperate with
the staff
 Patient is recoverd within a few minute, adult are able to drive a
car after 30 minutes
 Severe side effects are missing
Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University
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Clinic of Stomatology, Institutions Shared with St. Anne's Faculty Hospital, Faculty of Medicine,
Masaryk University