Nitrous Oxide / Oxygen Sedation : Review & Avoiding Serious Adverse Evenets

1. Nitrous Oxide & Oxygen
Avoiding Serious Adverse Events

2. Disassociative Drug
 Dissociatives (also referred to as 'dissociative anaesthetics’)
 are a class of psychedelic drug.
 This class of drug is characterised by distorted sensory perceptions
 and feelings of disconnection or detachment from the environment and self.1
 The word dissociative means detached from reality.
 https://adf.org.au/drug-facts/dissociatives/

3. Dissasociative
Drug
Anesthetic
Anxiolysis
Analgesic
Cellular mediators
(Dynorphins) stimulate
Opioid pathways
GABA pathways

4. Mechanism of action
 The anesthetic effect of nitrous oxide is through non-competitive NMDA
inhibition in the central nervous system.
 The analgesic effects occur through the release of endogenous opioids
 act on opioid receptors; its analgesic actions are like morphine.
 The anxiolytic effects are through GABA-A activation
 Nitrous oxide has a central sympathetic stimulating activity that supports
blood pressure, systemic vascular resistance, and cardiac output.
 Nitrous oxide stimulates cerebral blood flow and increases intracranial
pressure.[3]
Nitrous OxideKayla Knuf; Christopher V. Maani. Last Update: July 23, 2021
https://www.ncbi.nlm.nih.gov/books/NBK532922/

5. NMDA receptor antagonist
 work to antagonize, or inhibit
 the action of, the N-Methyl-D-aspartate receptor (NMDAR).
 They are commonly used as anesthetics for animals and humans;
 the state of anesthesia they induce is referred to as
 dissociative anesthesia.
https://en.wikipedia.org/wiki/NMDA_receptor_antagonist#:~:text=NMDA%20receptor%20antagonis
ts%20are%20a,referred%20to%20as%20dissociative%20anesthesia.

6. Physiological
and Physical
Characteristics

8. Nitrous
oxide
Relatively insoluble
 Blood gas partition coefficient .47
 Remains unchanged
Does not combine with blood
Does not disassociate
 Uptake by body is limited
 Equilibrium is achieved quickly
 Peak clinical effects seen 3-5 minutes after
initiation

9. Partial
pressure
 N2O 31 times greater than Nitrogen
 Therefore
 Nitrous oxide rapidly replaces nitrogen
Occupies the space of nitrogen
Increases volume and pressure of that
space
Due to the slower elimination of
nitrogen

10. Hazard risk
Open nitrous oxide valve slowly
At elevated temperatures, nitrous oxide
is a powerful oxidizer similar to
molecular oxygen.

11. Explosive Potential
Do not use organic lubricants on
fittings
Nitrous oxide supports
combustion by releasing the
dipolar bonded oxygen radical,
and can thus support ignition
from a spark in the presence of
oxygen

12. Date of download: 9/30/2021 Copyright © 2021 American Society of Anesthesiologists. All rights reserved.
The fire triangle. The three components essential to creating a fire and examples of common sources of each in the operating room
(OR). ETT, endotracheal tube. Revised from Jones et al.62
Figure Legend:
From: Operating Room Fires
Anesthesiology. 2019;130(3):492-501. doi:10.1097/ALN.0000000000002598

13. Operating Room Fires
 A patient was undergoing maxillofacial
surgery with general anesthesia maintained
through a nose mask with a concentration of
25% oxygen, 75% nitrous oxide, and a small
percentage of halogenated anesthetic.
 The patient had a moustache.
 As the surgeon was grinding a filling with a
tungsten-carbide bur, an incandescent spark
flew from the bur and arced out of the
patient's mouth, over his upper lip, and
landed in his moustache.
Anesth Prog. 2012 Fall; 59(3): 105–106.doi: 10.2344/0003-3006-59.3.105PMCID: PMC3468287
PMID: 23050749
Prevention of Fire in the Dental Chair Joel M. Weaver, DDS, PhD

14. Oral Fire Hazards
Electrocautery, electrosurgery, laser
units, as well as fiber-optic light units
and cables,
are very common sources of intense
heat in the dental office.
Even sparks from a high-speed drill
contacting hard tissue or metal plates
and screws
can ignite a fire if a dry gauze throat
screen and a high concentration of
oxygen are present.
Anesth Prog. 2012 Fall; 59(3): 105–106 doi: 10.2344/0003-3006-59.3.105
PMCID: PMC3468287 PMID: 23050749
Prevention of Fire in the Dental Chair Joel M. Weaver, DDS, PhD

15. Ultrasonic energy creates a direct
heating effect
due to rapid vibration of the tips of the
device
without the transfer of electromagnetic
energy to the tissue
but can cause elevation in tissue
temperatures to more than 200°C.36,38
Ultrasonic
Energy Source For Fire
Operating Room Fires
Teresa S. Jones, M.D.; Ian H. Black, M.D.;Thomas N. Robinson, M.D.; Edward L. Jones, M.D.
Anesthesiology March 2019, Vol. 130, 492–501.

16. Laser
Energy Source For Fire The second most
common ignition
source
the “light
amplification by
stimulated
of radiation,”
commonly known
the laser.39
Lasers are used in
cosmetic, eye, and
oral surgeries—
all areas above the
xiphoid that are
considered high-
Operating Room Fires
Teresa S. Jones, M.D.; Ian H. Black, M.D.;Thomas N. Robinson, M.D.; Edward L. Jones, M.D.
Anesthesiology March 2019, Vol. 130, 492–501.

17. Fiber Optic Light
Energy Source For Fire
One additional ignition source
warrants specific mention due
to its increasing use: the
fiberoptic light cord.
Heat generation of the lamp in
close proximity to the surgical
site
may be an issue

18. Medical History
Medical Care
 Air spaces
 Intrinsic factor / Gastritis / Chrons
 Anemia / Sickle Cell
 Neuropathy
 Vitamin B12 deficiency
 Psychiatric, Panic or anxiety
Medications
 General Classifications
 Compare to medical history
 Any med without a diagnosis?
 Any diagnosis without a med?
 Medical Consult

19. Review of Systems
 HEENT
 Respiratory
 Cardiovasular
 Muscloskeletal
 Neurologic / Craniologic
 Pancreatic
 Renal
 Hepatic
 Reproductive
 Immunological
 Hematological

20. ASA Classification
 II - Mild systemic disease
 mild to moderate
disturbance
 under good control
 no significant
compromise to normal
activity
 Appropriate
candidate for N2O2

21. ASA Classification
 III - Severe systemic disease
 Major systemic disturbance
 Difficult to control
 Significant compromise to normal
activities
 N2O2 - only after medical consult

22. ADA Recommendations
Focused physical evaluation prior to minimal sedation
• Operator must be prepared to handle
• the next deeper level of sedation than intended
Verbal & written instructions before sedation admin.
• ASA guidelines - no fatty foods prior, clear liquids
• light meal 1 - 2 hours prior

23. Minimal
Sedation
Vital sign requirements
• BP, pulse, respiration, PO2
preoperative = baseline
to compare to post op
postoperative =
objective measurement
of recovery

24. Vital Signs
Pre-operative, intraoperative, postoperative
• is considered Standard of Care
Medical
height, weight, body temperature
Dental Care
blood pressure, HR , Rhythm, Rate of respiration, PO2
Pain level & Anxiety Level

25. Possible
Contraindications
Medical Consult /
Delay
Pregnancy
Sinus
Infection
Ear infections
Debilitating
CV Disease
Phobia Bronchitis
Mental
Illness
Late Stage
HIV
COPD TB
Bowel
Obstruction
Alcohol or
Drug Abuse
Pulmonary
Hypertension
Prior Hx of
Drug Abuse

26. Absolute
Contraindications
Severe Cardiac Disease Neuropathy Critically ill
COPD
Hypoxic Drive
Cystic
Fibrosis
Ophthalmic
Surgery
Pneumothorax
1st Trimester
Pregnancy
Bowel Obstruction
Severe Psychiatric Disorder Middle Ear Surgery Vitamin B12 Deficiency
Use of Cautery Instr. Anemias
Retinal Surgery w/ gas
bubble

27. Look for
Medical
Contraindications
Air Spaces, eye
surgery, sinus,
middle ear
Anemias, vitamin
B deficiency,
Sickle Cell
Severe Anxiety
or mental health
concern, drug
addiction
GI disease
affecting
intrinsic factor
Neurological
Disorder

28. Paranasal Sinuses
 Nitrous oxide increases the volume
of air within sinus space
 When sinus spaces are blocked
 The pressure will increase
 Creating possible pain and injury

29. Otitis Media
 Eustachian Tube Blockage
 Pressure will increase
 Possible rupture of tympanic
membrane
 Potential hearing loss

30. Gastrointestinal Gases
 Blockage of bowel
 Creates increased pressure
within intestine
 Distension of intestine wall
 Can create diverticula, pain,
bowel distension or rupture

31. Nitrous
Oxide /
Oxygen
Sedation
Nitrous oxide replaces
nitrogen 31:1
Inactivation of methionine
synthetase
Inactivation of
cyanocobalamine vitamin B12

32. B12 Deficiency and Clinical Presentation in the
Setting of Nitric Oxide Use
 N2O's mechanism of action involves noncompetitive NMDA inhibition
 in the central nervous system,
 secretion of endogenous opioids,
 and GABA-A stimulation [10].
10. Knuf K., Maani C. V. StatPearls. Copyright © 2020.
Treasure Island, FL, USA: StatPearls Publishing LLC.; 2020. Nitrous oxide.

33. Complications
caused by
nitrous oxide in
dental sedation
 N2O may cause irreversible inactivation of vitamin B12 [29],
 an essential nutrient that acts as a cofactor in the folate and
methionine cycles in humans [30].
 Vitamin B12 deficiency may cause megaloblastic anemia in the
peripheral blood and bone marrow,
 subacute combined degeneration (SCD) of the spinal cord,
polyneuropathy, optic nerve injury, glossitis, dementia,
thrombosis, and/or infertility [31,32,33,34].
 In children, the possibility of Vitamin B12 deficiency should be
carefully monitored as
 it can impair the development of the brain and the overall
growth, which may lead to permanent disabilities [35,36].

J Dent Anesth Pain Med. 2018 Apr; 18(2): 71–78.
Published online 2018 Apr 27. doi: 10.17245/jdapm.2018.18.2.71

34. Methionine
Synthetase
 Nitrous Oxide Inhibits methionine synthetase
 Nitrous oxide irreversibly oxidizes the cobalt I (Co+) form of cobalamin
(vitamin B12) to Co3+
 prevents cobalamin (vitamin B12) acting as a coenzyme for methionine
synthase
 Impairing production of proteins
 RBC
 Myelin

35.  nitrous oxide is known to cause a neuropathy similar to that seen
in pernicious anaemia,
 we postulate that nitrous oxide analgesia combined with low B12
levels was the cause of the marked neuropathy in these patients.
 As a result of our observations and the probable association,
 we now do not use nitrous oxide analgesia in the management
patients with sickle cell disease.
Sickle cell disease and nitrous oxide-induced neuropathy
O Ogundipe1, M W Pearson, N G Slater, T Adepegba, N Westerdale
Affiliations
•PMID: 10671996
•DOI: 10.1046/j.1365-2257.1999.00261.x

36. Inactivation of methionine synthetase
Megaloblastic anemia Myelinopathy

37. Acute
megaloblastic
anemia caused by
inhalation of
nitrous oxide in a
patient with
multiple
autoimmune
pathology
 A megaloblastic state can arise over the course
of only a few days due to acute folate or
vitamin B12 deficiency.
 One of the most common causes, though
seldom reported, is the nitrous oxide (N02)
action in tissue.
 destroys methylcobalamin
 leading to the rapid development of a
megaloblastic haematopoiesis.
 This phenomenon may occur in patients
without previous vitamin B12 deficit,
 but is more frequent and severe when there is
a pre-existent deficiency state.
Acta Med Port. Sep-Dec 2000;13(5-6):309-12.
L Barbosa 1, I Leal, A T Timóteo, T Matias

38. Pernicious Anemia
 Pernicious anemia is defined as a type of
vitamin B12 deficiency that results from
impaired uptake of vitamin B-12 due to the
lack of a substance known as intrinsic factor
(IF) produced by the stomach lining.
 Pernicious anemia is a condition caused by
too little vitamin B12 in the body. It is one
form of vitamin B12 deficiency anemia.
 Vitamin B12 helps the body make
healthy red blood cells and helps keep nerve
cells healthy. It is found in animal foods,
including meat, fish, eggs, milk, and other
dairy products.
https://www.medicinenet.com/anemia/article.htm
https://www.semanticscholar.org/paper/Pathophysiology-and
-laboratory-diagnosis-of-anemia-Toh/e374cd3810f242792255f6a2aa9475bf41891664

39. Challenging Clinical Presentations of Pernicious
Anemia
 The most common cause of pernicious
anemia is the loss of stomach cells that make
intrinsic factor. Intrinsic factor helps the body
absorb vitamin B12 in the intestine. The loss
of parietal cells may be due to destruction by
the body's own immune system.
 Pernicious anemia can cause permanent
damage to nerves and other organs if it goes
on for a long time without being treated. It
also raises the risk for developing stomach
cancer.
 An autoimmune condition in which the
body's immune system attacks the actual
intrinsic factor protein or the cells in the
lining of your stomach that make it.
Challenging Clinical Presentations of Pernicious Anemia
Published on September 27, 2017, Author: Thein H Oo Specialty: Hematology, Medical Oncology, Internal Medicine
Institution: Section of Thrombosis & Benign Hematology, The University of Texas M.D. Anderson Cancer CenterAddress: 1515 Holcombe Blvd., Houston, Texas, 77030, United
States Author: Cristhiam M. Rojas HernandezSpecialty: Hematology
Institution: Section of Thrombosis & Benign Hematology, The University of Texas M.D. Anderson Cancer Center

40.  Neurologic symptoms associated with nitrous oxide use have been
attributed to vitamin B12 deficiency.
 Through oxidation, nitrous oxide inactivates vitamin B12.
 In its inactive form, vitamin B12 is unable to function as a co-
for
 methionine synthase
 converts homocysteine into methionine,
 which is necessary for the production of myelin proteins,
 while also converting 5-methyl-tetrahydrofolate into
tetrahydrofolate,
 which is necessary for DNA synthesis.
 and methylmalonyl coA mutase.
 converts methyl-malonyl CoA into succinyl CoA [1].
Cureus. 2020 Jul; 12(7): e9088.Published online 2020 Jul 9. doi: 10.7759/cureus.9088PMCID: PMC7366039PMID: 32685323
Nitrous Oxide-Induced Vitamin B12 Deficiency Resulting in Myelopathy
Monitoring Editor: Alexander Muacevic and John R Adler Victoria Campdesuner,
1 Yeshanew Teklie,
1 Talal Alkayali,
1 Derek Pierce,
1 and Justin George
1
Thompson AG, et al. Pract Neurol 2015;15:207–209.
doi:10.1136/practneurol-2014-001071

41. Published: August 06, 2019 (see history) DOI: 10.7759/cureus.5331
Cite this article as: Edigin E, Ajiboye O, Nathani A (August 06, 2019)
Nitrous Oxide-induced B12 Deficiency Presenting With Myeloneuropathy. Cureus 11(8): e5331.
doi:10.7759/cureus.5331
 Nitrous oxide interferes with vitamin
B12 metabolism,
 by oxidizing the cobalt atom and
irreversibly inactivating the enzyme
methionine synthetase [6].
 This impairs the production of
methionine (from homocysteine), a
substrate for tetrahydrofolate and
thymidine during DNA synthesis.

42.  Vitamin B12 deficiency is common
among the elderly.
 Elderly people are particularly at risk
of vitamin B12 deficiency because of
the high prevalence of atrophic
gastritis-associated food-cobalamin
(vitamin B12) malabsorption, and the

 increasing prevalence of pernicious
anaemia with advancing age
 prompt treatment is required to
reverse the damage before it
becomes extensive or irreversible.
•. 2015 Apr;21(2):155-64.
doi: 10.12809/hkmj144383. Epub 2015 Mar 10.
Vitamin B12 deficiency in the elderly: is it worth screening?

43. Nitrous Oxide & Pregnancy
 Nitrous oxide is classified as a
pregnancy risk group Category C
medication,
 meaning that there is a risk of fetal
harm if administered during
pregnancy.
 It is recommended that pregnant
women, both patients and
staff, avoid exposure to nitrous
oxide.
 Apr 1, 2019

44. Nitrous Oxide &
Birth Defects
 Six babies born to nurses in the Leyenburg
Hospital, The Hague, have serious deformities.
Following a confidential investigation by
Nijmegen University Medical Centre,
 the inhalation of the anaesthetic laughing gas
was blamed for these abnormalities.
 During pregnancy, the mothers, who worked
as nurses in the delivery room, would have
inhaled the gas when changing gas cylinders
and when removing masks from women who
had been given it as an analgesic during
delivery.
Laughing gas likely cause of babies' deformities
Inhalation of anaesthetic laughing gas was blamedfor the deformation
of six babies born in the Leyenburg Hospital, The Hague.
Report: Michiel Bloemendaal 07.08.2006
https://healthcare-in-europe.com/en/news/laughing-gas-likely-cause-of-babies-deformities.html

45. Nitrous
MAC
104%
Least potent of all inhalation
anesthetics
Nitrous alone will not produce
profound surgical anesthesia
Safety
High MAC
Low potency
Insoluble
Partial Pressure 31x Nitrogen

46. Scavenging capability
 Nasal hood
 has suction to remove exhaled nitrous oxide
 Provide fresh gas to patient
 Provides nitrous oxide / oxygen
 provides removal of nitrous to outside

47. Safety Features
 Fail Safe – ensures no nitrous will be delivered unless oxygen is
flowing
 Minimum of 30% oxygen at all times
 Ambient air 21% oxygen
 30% allows for calibration error
 Pin Index safety system
 Oxygen can only be attached to oxygen yoke

48. Drugs Are
Additive
You Must Be Prepared
For The Next Deeper Level …
or More

49. Analgesic Properties
 every 10% of N2O is equivalent to the effect of 5 mg morphine
 20 % nitrous = 10 mg. MORPHINE
 20% Nitrous - 80% Oxygen
 1 L/min nitrous to 4 L/ min oxygen
 1 L / 5 L - 20%
 1.5 L nitrous / 6 L tidal volume
 25% nitrous
 Would Your Patient React
 To 15 mg. Morphine? Absolutely!!!!!
 Patients will tell you they don’t feel the effect
 Wait longer for the effect
Comparison of analgesic and anxiolytic effects of nitrous oxide in burn wound treatment
A single-blind prospective randomized controlled trial
Li, Lin MMa; Pan, Qiong MMb; Xu, Le MDb,∗; Lin, Renqin MMc; Dai, Jiaxi MMc; Chen, Xinyan MMa; Jiang, Meiyun BSa; Chen, Zhaohong BSa
Editor(s): Zhang., Qinhong
Medicine: December 2019 - Volume 98 - Issue 51 - p e18188

50. Analgesic
Properties
 Will raise patients pain threshold
 Nitrous will manage both fear and pain
 Will produce a sense of well-being
 Will manage MILD fear

51. Nitrous Oxide Abuse

52. “
”
Pharmacologic evidence that nitrous oxide is addictive
through direct interaction with the endogenous opioid system includes
the possibility that it is a partial agonist
and acts at the mu, kappa, and sigma opioid receptors.
Additive Effect of Nitrous and Opioids / Benzodiazepines
Nitrous oxide, an opioid addictive agent. Review of the evidenceM.A. Gillman, B.D.S., M.Sc., D.Sc.
VOLUME 81, ISSUE 1, P97-102, JULY 01, 1986. AMERICANA JOURNAL OF MEDICINE

53. No Laughing Matter:
What You Need to Know
About Nitrous Oxide Addiction
Do not recommend using nitrous oxide,
if the patient has “severe emotional disturbances or drug related dependencies.”

54. Nitrous Oxide Abuse
 https://www.sobriety.ca/nitrous-oxide-recreational-drug-use.htm
 https://oxfordtreatment.com/prescription-drug-abuse/nitrous-oxide/
 https://lagunatreatment.com/drug-abuse/nitrous-oxide/

55. Opinion: How addiction to WhipIts nitrous oxide
killed my life partner
https://www.mercurynews.com/2021/05/05/opinion-how-
addiction-to-whipits-nitrous-oxide-killed-my-life-partner/

56. During the pandemic, Amanda acquired thousands of
cannisters as smoke shops delivered them to her
doorstep
 For people, like Amanda, who suffer from medication-resistant depressive
episodes,
 nitrous oxide appears to be an appealing alternative to traditional psychoactive
substances. It
 delivers a short burst of euphoria and a dissociative break from painful reality.
 It is (mistakenly) perceived as safe and non-addictive. And it is readily available on
every city block in smoke and tobacco shops.
https://www.mercurynews.com/2021/05/05/opinion-how-
addiction-to-whipits-nitrous-oxide-killed-my-life-partner/

57. The Opioid Epidemic…
Worse NOW, Than Ever Before
COVID-19 and the Drug Overdose Crisis: Uncovering the Deadliest Months in the United States, January‒July 2020
Joseph Friedman MPH, and Samir Akre BSAuthor affiliations, information, and correspondence detailsAccepted: February 25, 2021Published
Online: August 09, 2021
We found that 9192 people died from drug overdose in May 2020—
making it the deadliest month on record—representing a 57.7%
increase over May 2019.
Most states saw large-magnitude increases, with the highest in West
Virginia, Kentucky, and Tennessee.
We observed low concordance between rolling 12-month aggregates
and monthly pandemic-related shocks.

58. NORC University of Chicago
CHICAGO, Sept. 27,
2018 —
Thirty-two percent of
American adults have
received a prescription
for opioids
in the past two years,

59. OPIOID EPIDEMIC + Covid
Compromised Competency = Transmission
 2 years = 32%
 1 year = 16%
 16 in 100 patients
 1.6 in. 10 patients
 Medical histories given by patients
at this time frame 2018
 DID NOT SHOW 1.6 IN 10
PATIENTS WERE TAKING OPIOIDS
VETERANS ARE SLIGHTLY HIGHER
White, Suburban & Addicted to Heroin

61. DrugFacts
Substance Use and
Military Life
DrugFacts
National Institute
on Drug Abuse
More than one in ten veterans
have been diagnosed with
a substance use disorder,
 slightly higher than the
general population.3

62. Prescription Opioid Use among Adults with Mental Health
Disorders in the United States
Matthew A. Davis, Lewei A. Lin, Haiyin Liu and Brian D. Sites
The Journal of the American Board of Family Medicine July
2017, 30 (4) 407-417; DOI:
https://doi.org/10.3122/jabfm.2017.04.170112
SSRI, NSRI, MAOI, TCA,
Antipsychotics
Antianxiety / Benzodiazepines
Opioids
Mental Health Crisis in USA
Panedmic, Economics,
Employment, Retirement Plans
Apparent Self-medication for Depression, Anxiety & mood disorder

63. Data: Seniors prescribed
benzodiazepines most often
By Alison Pereto | August 6, 2018
Aetna Health
7 to 8 % of patients
Aged 30 – 65 or older
Are taking benzodiazepines
This is .7 patients - .8 patients
Every ten patients treated
Nearly 1 in 10.
Do Patients REVEAL THIS?

64. Why Do Patients Lie to Their Doctors?
For best results, the doctor-patient relationship should be built
on mutual trust and honesty.
By Elaine K. Howley
|
Jan. 7, 2019. US News
 JAMA Network Open found that 60 to
80 percent of patients have been less
than fully forthright with their doctors at
some point.
 Sometimes he'll ask the same question
in multiple contexts and seek
clarification if it seems a patient isn't
being fully truthful.
 "You ask them open-ended questions
but you keep tightening up the
questions as you get answers."
 In addition, he looks for non-verbal clues
such as fidgeting, long pauses before
answering and anxiety –
Slow Titration Is The Standard of Care
.5 L no sooner than 3-5 minutes

65. Patient - self-medication
Sometimes they tell you
& some times they ….. dont

66. Anxiolysis
 minimal sedation
 (previously known as anxiolysis)
 a minimally depressed level of consciousness,
 produced by a pharmacological method,
 that retains the patient's ability to
independently and continuously maintain an
airway
 and respond normally to tactile stimulation
and verbal command.

67. Receptors
 GABA Receptors
 Mu Opioid Receptors

68. Medications
 Analgesics (Opioids)
 Anxiolytics
 Hypnotics / Sedatives
 Additive to Nitrous Pathways

69. Minimal Sedation
 Minimal sedation
 Titration of Drug
 Less than 50% nitrous
 Risks are minimal
 Adverse effects are minimal

70. Minimal sedation
 Anxiolysis
 Drug induced state
 During which patient responds normally to
verbal commands
 Cognitive functions & coordination may be
impaired
 Respiration and CV functions unaffected
 Nitrous oxide < 50%

71. Moderate Sedation
 Drug induced
 Depression of consciousness
 Patients respond purposefully to verbal commands
 May need stimulation to respond
 No intervention is required to maintain airway
 Spontaneous respiration
 CV function of normal
 Nitrous oxide > 50%

72. Advanced airway management
 May be needed for moderate sedation
 that can fall into deep QUICKLY
 Positive pressure ventilation
 Ambu bag mask
 Nasotracheal tube
 Oropharyngeal tube

74. Pre and Post Oxygenation

75. Patient Comfort

76. Nasal Hood
 Gas delivered to patient thru nasal hood
 Designed to fit snugly over patient’s nose
 Gas should not leak out

77. Alveolar
Ventilation
 Amount of air per minute entering alveolar units
 Less than minute volume
 Not all air enters alveoli
 Conduction or dead space
 Subtract dead space from tidal volume and multiply by
respiration rate
 (Tidal Volume – Dead Space) x Respiration Rate

78. Gas Exchange
 Dependent on partial pressure of gas in
 Lung / alveoli
 Blood
 Amount of gas dissolving in blood depends on its
 solubility
 partial pressure
 Moves from high to low pressure / concentration
 Rate of dissolving depends on pressure gradient

79. Gas Exchange

80. Gas
Exchange
Amount of gas absorbed by blood
determined by its solubility
Low solublity = high diffusion rate (RAPID)
Little gas is absorbed
by blood elements
Rapid onset due to
rapid diffusion and low
solubility
Rapid rate is the same
when pressure gradient
is reversed
Rapid Recovery

81. Diffusion
Hypoxia
 Rapid Diffusion due to low solubility
 N2O exits rapidly
 More rapid than Nitrogen replacing it
 Supply of O2 is diluted
 Reducing PO2 saturation
 Pulse oximetry : oxygen saturation = oxyhemoglobin
 Amount of oxygen carried in blood
 100% Oxygen 3-5 minutes after nitrous prevents this

85. Nitrous level greater than 50%
Practitioner is responsible for
intended level and next level of
sedation
Intended level is minimal < 50%
Next level is Moderate
•Some patients are hyper-responders
•Some patients take medications and effect is additive
Pre procedural fasting may be needed if moderate sedation is used to
prevent aspiration
Moderate Sedation
By using >50% you are responsible for DEEP Sedation
Advanced Airways & Resuscitation

86. Target Level
Minimal Sedation < 50%
Responsible For Moderate
Patient Comfort is true target

87. If Moderate
Sedation
Occurs
Responsible for Deep Sedation
Protective Reflexes & Spontaneous Breathing Lost
Advanced Airway Rescue Needed

88. Airway Management - BLS
 Head tilt - chin lift
 Positive pressure ventilation
 Full face mask and ambu bag
 Aspiration of vomitus is unlikely
 If protective reflexes are intact
 If vomiting occurs
 suction pharynx
 Oxygen 100%
 DC dental care

90.  Used for moderate sedation
 Intentionally or unintentionally
 Light meal
 with no fried or fatty foods
 Within 6 hours
 No liquids 2 hours prior
Pre-procedural Fasting

91. Moderate Sedation
 Clear liquids 2 hours prior (water / juice / no pulp)
 Non-human milk - 6 hours prior
 Light meals - 6 hours prior (toast & clear liquids)
 gastric emptying
 prevent aspiration of vomit

92. Informed
Consent
 Understand the purpose of the procedure
 How it will be accomplished and what to expect
 Benefits & risks of sedation
 Opportunity to ask questions
 Competent patient or legal guardian

93. Titration
Method of delivering incremental amounts of drug
Until desired endpoint is reached
Given until patient is relaxed and comfortable

94. N2O
Objective
 Patient COMFORT
 Ask them if they are comfortable
 Are we ready to begin
or do you feel like you need a little more relaxation?
Remember - MINIMAL SEDATION
Less than 50% N20

95. Key To Success
Titration of N2O Careful observation
of the patient
Complete recovery

96. BEGIN WITH
OXYGEN
Start with 6-7 L/min.
100% oxygen
• start with more to avoid
suffocating feeling
Flush the system
with O2 until bag is
inflated 2/3
Have patient place
nasal hood & adjust
hoses
Determine minute
volume - Tidal
Volume

97. Minute
Volume
Ask patient to
breathe thru
their nose - not
mouth
01
Ask patient if
they are able to
breathe easy
02
Adjust flow to
patient comfort
& bag is 2/3 full
• You will see bag
inflate and deflate
03

98. N2O
Administration
 Maintain minute flow thru the procedure
 Each time N2O is added
 O2 will have to be decreased
 Keeping minute volume constant

99. Dual Tube
Flowmeters
 Total liters flow is calculated
 By adding both sides of the flowmeter
 At the level of the middle of the floating ball

100. % Nitrous
Calculation
 Divide the L/minute of Nitrous
 by the TOTAL L/minute
 2L nitrous / 7L min = 28.5%
Appendix E

101. Standard of
Care
 The technique of titrating N2O is recognized as the standard of
care
 SLOW titration of small doses of drug
 Is important to prevent over sedation

102. Recommended
Regimen
 Begin with .5L N2O .5/6= 8%
 Add N2O increments as needed
Wait 3-5 minutes for full effect
.5L nitrous increments
Peak effect occurs at approximately 5 minutes

103. Signs of Sedation
Glassy eyes, droopy & heavy eyelids
Diminished eye movement
Flushing / redness of face / neck
Warm feeling
Feeling heavy and relaxing into chair
Facial muscles more relaxed / Smiling
Slight tingling of digits,
Feeling of relaxation & comfort

104. Signs of Oversedation
Significant slurred speech
Response to verbal command poor
Ptosis of eyelids with difficulty opening
Any loss of consciousness
Significantly lowered hemodynamics
Cyanosis / hypoxemia
Blue lips, nail beds, low PO2

105. Recommended
Regimen
 Wait at least 3 – 5 minutes after a dose delivered
 Before adding next increment
 When sedation is becoming evident
 Wait longer for the drug to take full peak effect
 Before adding another dose to avoid over sedation

106. Recommended
Regimen
 Ask patient to breathe thru their nose and keep their lips
sealed
 Talking and verbalizing to operator will alter sedation
 Contaminates room air with nitrous

107. Goal
 Patient comfort
 Titrate to a level of sedation that is
 Determined by patient comfort and relaxation
 Minimal Sedation <50%

108. Intraoperative
Monitoring
 Cumulative effects of N2O will be seen
 as duration increases
 Sedation may deepen and result in uncomfortable symptoms
 Reduce nitrous and adjust oxygen
 Periodically ask patients how they feel
Titration up or down
to comfort
Minimal Sedation

109. Intraoperative
Monitoring
 Decrease N2O incrementally for non stimulating phases of care
 Add oxygen as you diminish nitrous
 If nearing completion of care you may terminate N2O
 When you terminate N2O
 Deliver 100% Oxygen for at least 5 minutes
 At established minute volume

110. Recovery
Recovery /emergence
is a mirror image of
induction
Patient returns to
original emotional
state
N2O has rapid onset
and emergence

111. Recovery
 Post operative oxygenation
 100 % oxygen
 Minimum of 5 minutes
Or longer as needed by patient
assessment

112. Recovery
Assess patient response to questions
Ask how they feel before removing nasal
hood
Should indicate they feel fine, not drowsy,
light-headed, groggy, dizzy or nauseated
If ANY indication of not feeling normal
continue O2

113. Recovery
Continue 100% Oxygen as
long as is necessary

114. Adequate Recovery
 Patient alert and oriented
 Vital sign values stable and WNL
 Within 10% of pre op vitals
 Patient states they feel normal

115. Recovery
Simple hand-eye
coordination
• instruct patient to place one
finger on tip of nose
If this simple skill cannot
be completed
• continue oxygen until recovered

116. Recovery
 ONLY after patient is recovered and feels
normal
 May the oxygen and nose piece be
removed

117. Recovery Time
Minimum of 5
minutes
Each patient
will differ due
to biovariability
It may take
longer for
some

118. Record
Keeping
 ASA classification
 Indications for nitrous use
 Medical history and medications
 Fasting status
 Preoperative, intraoperative, and post operative vitals

119. Record
Keeping
Patients minute volume
Peak percentage of nitrous
Duration of nitrous administration
BP, HR, Rhythm, Respiration Rate, PO2
Adverse reactions
• Oxygen time and patient response
Assessment of recovery