QUIZ 3: Week 5 Lecture 1: Nitrous Oxide/Oxygen Inhalation Sedation

What are the characteristics of nitrous oxide?

nitrous oxide + oxygen = nitrous oxide/oxygen gas

no known allergies and does not irritate the lungs

colorless, odorless, nonflammable

What is nitrous oxide used for?

patients of all ages to help manage mild/moderate anxiety

What are the properties of nitrous oxide? (what can it do?)

Analgesic Properties (Pain relief, when someone is anxious, their pain threshold is lower and they experience more pain)

Anxiolytic Properties (Anxiety relief)

Amnestic Properties (Time distortion)

What is the onset of action for N2O?

rapid

What is the length and depth of sedation for N2O?

can be used for long or short periods

What is the elimination and recovery of N2O?

rapid

give pt oxygen after for 2 - 5 min

Do pts accept N2O well?

yes, as long as we don't over sedate

Define titration

a method of administering a drug in incremental amounts over time until a desired endpoint is reached

allows us to give the proper amount to the pt and give them a positive experience

Compare N2O and Local Anesthesia

Local anesthesia manages pain by blocking pain response

Nitrous does not block the pain response, but relaxes patients

How is N2O inhaled and absorbed?

inhaled into the lungs by the nose

rapidly absorbed by the lungs

What happens as N2O fills the lungs quickly?

High pressure in the lungs

Causes diffusion of N2O out of the lungs into the blood (difference in partial pressures)

Blood carries the nitrous oxide to the brain quickly and effects are rapid

How is N2O eliminated?

unchanged by the lungs

it is not metabolized, leaves the body in the same form and is not stored

most is exhaled through the lungs 3-5 min after administration and 1% released through urine/sweat

Who benefits from N2O?

Control of anxiety, apprehension

Apprehensive of injections

Those who can't handle long appointments

Children --> dfficult management, apprehension, very young, must be able to respond

What levels of sedation will DH do with N2O?

minimal or moderate

Describe minimal sedation (% given, how the pt responds)

Less than 50% nitrous oxide

Anxiety is reduced & patient is relaxed

Patients can respond normally to verbal commands

Describe moderate sedation (% given, how the pt responds)

>50% nitrous oxide OR <50% nitrous oxide + another sedative

"Conscious sedation"

Produces greater depressed

Consciousness

patients can still respond

Describe Deep Sedation & GA

Beyond DH scope of practice

Patients become less responsive

Spontaneous ventilation is inadequate

Intervention to maintain airway may be required

What are the legal considerations regarding N2O?

Must complete CPR training and maintain

Must use fail-safe equipment, capable of positive pressure respiration

Must complete a course from an accredited institution

12 hours minimum with didactic and administer at least three supervised cases

What does N2O/O2 depress?

the CNS (exact mechanism unknown)

What can chronic exposure to N2O cause?

injury of the nervous system --> numbness and weakness of the extremities are symptoms

How does N2O affect the cardiovascular system?

No negative or significant effects

Blood flow to major organs is not significantly affected

Positive effects due to supplemental oxygen

Blood pressure and pulse may decrease (bc pt is more relaxed)

Vasodilation occurs –-> flushing around the patient’s face and neck may be observed

How does N2O affect the respiratory system with minimal sedation?

Breathes normally

Mild decrease in rate

Gag reflex is reduced

What are the post op side effects of N2O?

Nausea / Vomiting

Dizziness

Reduced heart rate or respiration rate

Diffusion Hypoxia

What are the breathing problems & lung conditions that are contraindications for receiving N2O? (4)

1. Difficulty breathing through nose --> common cold, sinus infection, allergy related symptoms

2. Emphysema or Bronchitis (COPD)

3. Upper respiratory tract infections

4. Cystic Fibrosis

Can pts with asthma receive N2O?

yes

What are other contraindications to N2O? (7)

1. Pneumothorax --> abnormal collection of air in lungs

2. Pneumoencephalography --> cerebrospinal fluid drained from brain

3. Severe phobia, taking sleep inducing medication, antidepressants, or psychotropic --> can cause hallucinations

4. 1st tri of pregnancy

5. Significant bowel obstruction

6. Cancer treatment with bleomycin sulfate

7. Severely phobic individuals

What are conditions that you should seek medical consultation first before administrating N2O? (5)

1. Pernicious / megaloblastic anemia

2. Vit B12 deficiency

3. Cognitive disorders (assess level of understanding, need to be able to communicate)

4. Middle ear disturbances

5. Recent eye surgery with perfluoropropane or sulfur hexafluoride gas

Where is the manufactured product kept?

kept refrigerated until it is directly transferred by insulated trucks in color coded cylinders

What is the pressure (psi) of N2O throughout the procedure?

750 psi until 20% left, then it will start to decrease

How is N2O stored?

as a liquid

What is the pressure (psi) of O2 at full?

2000 psi

How is O2 stored?

as a gas

What is the max N2O that can be administered?

70%

What is the min O2 that can be administered? (we absolutely have to give at least this much)

30%

What is the size range of the tanks?

A - H (A is smallest)

E is most common with 16 gal

What are the systems of N2O?

central or portable

What are the parts of a N2O system?

yoke stand

yoke

pin index system

reducing valve

flowmeter

flowmeter's fail-safe mechanism

reservoir bags

conduction tubing

nasal hood

scavenger system

positive pressure oxygen hookup

What is the yoke stand?

for portable system

back bone and supporting structure for the tanks

What is the yoke?

metal framework that attaches the cylinder to the yoke stand

What is the pin index system?

equipment safety feature that ensures the right connections are made with the right cylinders via geometric shapes specific to each cylinder

What is the reducing valve?

Prevents dangerous pressure buildup

Alter high pressure (750 & 2000 psi) from cylinders to low pressure (50 psi) for patient delivery

What is the flow meter?

indicates the amount of gas being delivered to the patient

What is the flowmeter's fail-safe mechanism?

A valve opens to allow N2O flow only when there is a flow of O2 to the system

Anytime the O2 flow is <30%, N2O stops flowing

What is the percent of oxygen in room air?

21%

critical to maintain an O2 level of at least that present in the ambient air

What is the reservoir bag?

holds the mixed gases

What is the conduction tubing?

tubing through which gas is delivered

What is the nasal hood?

Where the N2O is delivered

Reusable or disposable

Scented or unscented

Different Sizes

What is the scavenger system?

Removes exhaled gases via vaccuum out of the building

One-way valve with two hoses

What is a silhouette system?

variation of nasal hood, more fitted

pt is more comfortable

easier to work on oral cavity

What is the positive pressure oxygen hookup?

can be attached to the equipment and used in case of emergencies to administer oxygen

What does appropriate sedation look like in a pt?

1. The patient appears comfortable and relaxed --> if asked, the patient may acknowledge a reduced sense of fear & anxiety

2. Signs of relaxation may include shoulders dropping, legs uncrossing, and arms positioned looser on arm rests

3. Patient’s eye activity will likely begin to slow --> eye movement will be reduced, and their blink rate will slow

4. Pts will smile easily, are aware and responsive

5. Some pts feel heavy or light

6. Vasodilation in face and neck / body feels comfortably warm

What does over sedation look like in a pt?

1. Relaxed, comfortable state has disappeared and pt doesn't feel the same

2. Effects may be intensified, symptoms may be intolerable, pts may show signs of agitation

3. Patients may hallucinate

4. Fixed eyes

5. Decreased awareness of surroundings

6. Hearing may change

7. Increased body warmth

8. Slurred words

9. Dizzy / spinning // nausea

Can loss of consciousness occur with oversedation?

YES

What do we do as providers before administering N2O

Prior to appointment, instruct not to eat heavily

Check equipment

Obtain medical history

Take vital signs - for minimal sedation, pre and post operatively -->

BP, Pulse, and Respiration

Informed consent

How do we set up the N2O?

Select the appropriate size and type of scavenging nasal hood

Start oxygen, place nasal hood on patient, and determine tidal volume

Check reservoir bag for flow/tidal volume --> should inflate and deflate

and breathing should be comfortable

Place nasal hood on and use 4 - 5 - 6 rule starting with O2

What is the proper technique while administering N2O?

Begin titration of N2O (.5-1L/minute)

Minimize talking

Assess patient for signs and symptoms of appropriate sedation, continuously monitor the patient, never leave the patient alone

Determine maintenance level

Perform procedure

Describe maintenance level

If pt's tidal volume is 6, the volume of O2 + N2O should always be 6

EX: Start with 5 L O2 and 1 L N2O and keep moving until pt feels properly sedated. Could end up with 3 L O2 and 3 L N2O, just must always equal 6 since that was their tidal volume

What is the proper technique while terminating N2O administrating?

Terminate N2O flow and administer a minimum of 5 minutes of postoperative 100% O2

Take vital signs again (postoperatively)

Document

What do you document post-op?

Vital signs before and after treatment

Maintenance level % and duration

Length of oxygen administration (should be 5 minutes)

Patient reaction and recovery

What is the recovery like of a pt after recieving N2O?

Patient does not usually require an escort

Ask how the patient is feeling --> give additional oxygen if the patient is not feeling back to normal

TRUE OR FALSE:

The amount of N2O required by a patient on any given day or time varies.

TRUE

Is there a direct causal relationship exists between reproductive health and scavenged low levels of N2O/O2?

No evidence --> but every attempt should be made to reduce the level of trace N2O to practitioners.

However, pregnant providers should know the exposure levels of N2O/O2 and use all recommended trace gas scavenging methods

Pregnant providers may choose to avoid the office setting and any N2O/O2 exposure for the 1st trimester.

How can we prevent over exposure to N2O/O2?

scavenging system or personal devices

What are some personal devices used for personal monitoring?

Infrared Spectrophotometry (IR)

Time-Weighted Average Dosimetry

Hand-Held Monitoring Device