Induction

Goals of Induction (5)

1. Smooth transition from awake to anesthetized (stage 1 to 3)

2. Decrease amount of inhalant used

3. Enable us to secure airway (in most cases)

4. Need muscle relaxation

5. These goals are often met with the use of injectable anesthetics

how many stages of anesthesia are there?

4

what phase is stage 1 known as

induction / disorientation

what phase is stage 2 known as

Excitement phase

stage 2 is known for (8)

1. Incoordination

2. Struggling

3. progressive relaxation

4. unconsciousness

5. May hamper restraint

6. predispose to injury

7. vomiting

8. cardiac arrhythmias

stage 3 is known as what phase

unconscious

what are the 3 stages in stage 3

1. Light

2. Surgical

3. Deep

what phase is stage 4 known as

overdose phase

Gas induction Concerns (9)

1. Restraint without restriction of breathing

2. Fear with stage 1/stage 2 can cause catecholamine release which predisposes to arrhythmias

3. Indicators of anesthetic depth difficult to assess

4. Exposure to waste gases

5. Longer induction time

6. Not able to protect the airway

7. Not able to prevent aspiration

8. Not able to provide ventilatory support

9. Harder to observe respiration

what are the different induction techniques (7)

1. IM induction (Single dose)

2. IV induction (Single dose)

3. IV induction and maintenance with multiple IV boluses (TIVA)

4. IV induction and maintenance with constant rate IV infusion (CRI)

5. Inhalation Induction and Maintenance with inhalation agent

6. IM induction and Maintenance with an inhalation agent

7. IV induction and Maintenance with an inhalation agent

IM induction (Single dose) is usually done if (2)

1. animal can’t be handled

2. not enough anesthetic machines

IM induction (Single dose) — be titrated

a. can be

b. can’t be

b. can’t be

IV induction (Single dose) Technique for — procedures that require less than — mins of anesthesia

short , 10 mins

procedure for Chamber Induction for a Dog or Cat (5)

1. Place the conscious animal inside an anesthetic chamber. The chamber should be large enough for the patient to lie down with its neck extended. If the patient can be handled, an ophthalmic lubricant should be applied before the patient is placed in the induction chamber.

2. Remove the Y-piece of a rebreathing circuit and attach one corrugated hose to each port of the chamber.

3. Deliver a mixture of oxygen at 5 L/min and isoflurane at 3%–5% or sevoflurane at 4%–5%.

4. During passage through stages I and II, patients typically exhibit fear and agitation. The patient may attempt to escape or vocalize. Gradually, with the onset of anesthesia, the patient will become increasingly depressed and immobile.

5. As soon as the patient can no longer stand, rock the chamber gently to assess the patient’s status. Initially, the patient will respond by righting itself until anesthesia is ofsufcient depth to prevent purposeful movement. When the patient is immobile enough to allow it to be safely handled, remove it from the chamber, place a mask, and proceed as with mask induction.

how To minimize exposure to waste anesthetic gas (7)

1. Ideally, enlist the help of two people (one to open, close, and manage the chamber and one to hold the patient) so that the waste gas can be managed without compromising patient safety.

2. Check that the lid is properly sealed before commencing chamber induction.

3. Perform chamber induction in an area that is well ventilated (with at least 15 air changes per hour).

4. Avoid opening the chamber any more often than necessary.

5. Turn the vaporizer off before removing the lid.

6. Ideally, before removing the lid, run pure oxygen to scavenge as much waste gas as possible. This is often not possible, however, because of the need to check vital signs rapidly, ensure a patent airway, and perform endotracheal intubation.

7. Remove the patient quickly, immediately replace the lid, and continue to run pure oxygen at a rate of 5 L/min for at least 2–3 min to purge waste gas from the system.

Sequence of events for induction of general anesthesia with an intravenous agent and maintenance with an inhalant agent in a small animal patient

1. Administer premedications IM approximately 15–20 min or IV approximately 5–10 min before anesthetic induction.

2. Place an intravenous catheter, attach a fluid administration set, and begin fluid administration.

3. Administer the induction agent.

4. Check the patient's readiness for intubation.

5. Place and secure the endotracheal tube.

6. Check the patient's vital signs.

7. Turn on the oxygen and connect the endotracheal tube to the breathing circuit.

8. Inflate the endotracheal tube cuff.

9. Turn the vaporizer on to the appropriate setting.

10. Determine the patient's anesthetic depth and commence regular monitoring.

11. Position and secure the patient for the procedure, giving attention to padding, maintenance of an open airway, unrestricted blood flow, and unrestricted chest excursions.

12. Attach monitoring devices.

13. Continue to monitor and adjust the anesthetic and oxygen levels as needed until completion of the procedure.

what is it

dorsal pharyngeal wall

what is it

esophageal aditus

what is it

circoid arch

what is it

corniculate process

what is it

piriform recess

what is it

cuneiform process

what is it

vocal folds

what is it

ventricle aperture

what is it

epiglottis

what is it

tongue

equipment required for intubation (7)

1. A length of IV tubing or rolled gauze to secure tube to patient

2. Syringes to inflate cuff (Proper size: Not too big!)

3. Light to visualise glottis

4. Stylette for smaller tubes to help with placement

5. Lidocaine injectable or gel (feline patients)

6. Laryngoscope

7. ET Tube

how many et tubes should be chosen

3

how to measure length for ET tube

Tip of nose to thoracic inlet

advantages of ET tube (6)

1. Maintain an open airway

2. More efficient delivery of anesthetic gas than a mask

3. Reduces risk of aspiration

4. Improve efficiency of gas exchange by reducing anatomic dead space

5. Anesthetist can support ventilation by manual or mechanical means

6. Reduces waste gas exposure to staff

complications of ET tubes (13)

1. Vagal Reflex

2. Damage to larynx, pharynx and glottis (may cause laryngospasm)

3. Pressure necrosis of trachea

4. Obstruction

5. Chewing tube in half

6. Infection

7. Cuff Not Inflated

8. cuff Underinflated

9. Overzealous Intubation

10. Tube Kinked

11. Obstructed

12. Tube Not Removed Before Return to Consciousness

13. improper size

what needs to be done when flipping a patient

disconnect breathing tube from the circuit

what can happen if Tube Not Removed Before Return to Consciousness (3)

1. Damage to the tube from chewing

2. Blockage of the airway

3. a severed portion of the tube can be aspirated or swallowed

what happens if the tube isn’t wide enough (3)

1. Poor seal

2. Restricts air flow

3. Small tubes more likely to block with mucus

what happens if a tube is Too wide / cuff overinflated (3)

1. Pressure on trachea, which could result in damage

2. Necrosis of the tracheal mucosa

3. Possibility of tracheal rupture in extreme situations

what happens if the tube is too long (3)

1. Ventilation of only one lung

2. Increased mechanical dead space

3. Leading to hypoventilation and hypoxia

what happens if the tube is too short (2)

1. Inability to intubate the patient successfully

2. Displacement of the tube from the glottis if the patient’s body position is changed

what happens if the Tube Not Cleaned and Disinfected (5)

1. Transmission of infectious agents

2. leading to tracheitis

3. bronchitis

4. pneumonia

5. Blockage of the tube with dried mucus or other foreign material

define Laryngospasm

Reflex closure of the glottis in response to contact with any object or substance

how to prevent laryngospasm (5)

1. Apply lidocaine to the arytenoids first

2. Wait 30-60 secs to take effect before attempting intubation

3. Be sure patient is adequately anesthetized before attempting to intubate

4. Wait for glottis to open before attempting and get tube in first time !

5. Never force the tube !!

When is our patient ready to intubate? (5)

1. Unconscious

2. Lack of voluntary movement

3. Absent pedal reflex (Pinch toe)

4. Sufficient muscle relaxation to allow the mouth to be held open

5. No swallowing when the tongue is grasped

Procedure of intubating (16)

1. Place the patient in sternal recumbency

2. Have an assistant grasp the patient’s maxilla behind the canine teeth, extend the neck, and raise the head so that the head and neck are in a straight line. Be sure the lips and whiskers are pulled dorsally and out of the line of sight. The neck should be propped upright and not allowed to sag. The as-sistant should not push on the ventral aspect of the neck, head, or throat because this may obscure the view, making intubation difficult.

3. Grasp the tongue with a gauze sponge and open the mouth fully by firmly pulling the tongue out and down. A mouth gag can be used to hold the mouth open.

4. Adjust the light so that the larynx is well illuminated

5. If necessary, use the tube or laryngoscope gently to displace the epiglottis ven-trally or the soft palate dorsally until the glottis can be visualizedb. When using a laryngoscope, press down on the base of the tongue below the epiglottis to aid in visualizing the glottis

6. Gently insert the tube past the vocal folds using a rotating motion, but never force the tube!. If the tube is too large to pass easily, exchange the tube for one of smaller diameter

7. After the tube has been placed, gently transfer the patient into lateral recumbency.

8. Check the tube to ensure that it is in the trachea. Then check that it is inserted to an appropriate distance and is oriented to match the natural curve of the trachea.

9. Secure the tube in place with a tie (e.g., length of used IV administration set tubing, hard roll gauze, shoelace, or commercial tie designed for this purpose).

10. Position the tongue so that it hangs loosely from the mouth and is not compressed by the tie.

11. Turn on the oxygen owmeter(s).

12. Connect the endotracheal (ET) tube connector to the breathing circuit.

13. Inate the cuff and check for leaks.

14. Turn on the anesthetic vaporizer and select the appropriate setting (if main-taining with an inhalant agent).

15. Commence regular monitoring.

16. ensure a patent airway by checking the position of the patient and tube. The neck and tube should assume a gentle natural curve.

how to confirm et tube placement (9)

1. Visualized

2. Bag movement

3. Feel for air movement

4. Fogging

5. Valves opening properly

6. Palpate

7. Patient ability to vocalize

8. Coughing

9. Capnograph (if no reading = not in the right place)

whats an SGAD

an alternative to an endotracheal tube for maintain-ing an open airway and transferring anesthetic gases directly from the breathing circuit to the lower respiratory tract

the v-gel advanced SGAD can be used in what animals (3)

1. cats

2. rabbits

3. dogs

what does SGAD stand for

Supraglottic Airway Devices