IVE_UK_Anaesthesia pocket guide

Anaesthesia
Nursing
Pocket Guide
1

Anaesthesia
Nursing
Pocket Guide
This pocket guide is for general
reference only and is not a substitute
for clinical judgment.
Drug doses and protocols should always
be adapted to the individual patient,
and local prescribing laws and licensing
regulations must be adhered to.
Ultimately, final decisions
rest with the attending
veterinary surgeon.
2

Drugs and Fluids
Emergency Doses
• Dextrose Boluses
Symptomatic hypoglycaemia
with blood glucose
<3.3 mmol/L (<60 mg/dL)
→ 1ml/kg 50% dextrose, diluted 1:4
with isotonic crystalloid,
administered IV over 5-10 minutes
• Emesis Induction
Apomorphine
→ 0.1 mg/kg SC (dogs)
3

EMERGENCY DOSES
• First-line anticonvulsants
Diazepam (5 mg/ml):
→ 0.5 mg/kg IV or 1 mg/kg rectally
(if IV access is not possible)
Midazolam (5 mg/ml):
→ 0.3 mg/kg IV
• Allergic reaction
Chlorphenamine:
→ Cats: 2–4 mg/cat IM/ SQ
→ Dogs < 20 kg: 4 mg IM/ SQ
→ Dogs >20 kg: 8 mg per dog IM/ SQ
4

DRUGS AND FLUIDS
Drug
Concentration
Dosage
• Sedation
Butorphanol
Midazolam
Acepromazine
Ketamine
Dexmedetomidine
Medetomidine
• Anti-emetics
Maropitant
Ondansetron
Metoclopramide
Diphenhydramine
10 mg/ml
5 mg/ml
10 mg/ml
100 mg/ml
0.5 mg/ml
1 mg/ml
10 mg/ml
2 mg/ml
5 mg/ml
50 mg/ml
0.2-0.4 mg/kg
IV/IM/SC
0.2 mg/kg
IV/IM
0.01-0.02 mg/kg
IV/IM/SC
1-5mg/kg
IV/IM
1-10 mcg/kg
IV/IM/SC
1-10 mcg/kg
IV/IM/SC
1 mg/kg IV/SC
0.1-1 mg/kg IV/
IM/SC
0.2-0.5 mg/kg
IV/IM/SC
2-4 mg/kg PO/
IV/SC
5

DRUGS AND FLUIDS
Drug
Concentration
Dosage
• Pain Management
Fentanyl
Buprenorphine
Methadone
Bupivacaine
Lidocaine
50 mcg/ml
0.3 mg/ml
10 mg/ml
2.5- 5 mg/ml
20mg/ml
3-5 mcg/kg
IV/IM
0.01-0.02 mg/kg
IV/IM/SC
0.1-0.5 mg/kg
IV/IM/SC
1-2 mg/kg
15 - 30 min prior
2-4 mg/kg
2 - 5 min prior
• Induction
Alfaxalone
Propofol (Dog)
Propofol (Cat)
10 mg/ml
10 mg/ml
10 mg/ml
2 mg/kg IV
up to 4
mg/kg IV
up to 6
mg/kg IV
6

DRUGS AND FLUIDS
Drug
Concentration
Dosage
• Reversals
Atipamezole (Dog)
Atipamezole (Cat)
Naloxone
Butorphanol
Flumazenil
5 mg/ml
5 mg/ml
0.4 mg/ml
10 mg/ml
0.1 mg/ml
= volume to
alpha 2
=Half of volume
to alpha 2
0.01-0.04
mg/kg
0.1-0.4
mg/kg
0.01
mg/kg
Atipamezole
Naloxone
Butorphanol
Flumazenil
Reverses: Alpha-2 adrenergic
agonists (e.g., Dexmedetomidine,
Medetomidine)
Reverses: Opioids (e.g., Butorphanol,
Fentanyl, Morphine, Buprenorphine)
Reverses: Opioid agonists (e.g.,
Fentanyl, Morphine)
Reverses: Benzodiazepines (e.g.,
Midazolam, Diazepam)
7

DRUGS AND FLUIDS
Drug
Concentration
Dosage
• NSAIDs
Carprofen
Meloxicam (Dog)
Meloxicam (Cat)
Robenacoxib
50 mg/ml
5 mg/ml
5 mg/ml
20 mg/ml
2 mg/kg
q 12 IV/SC
0.2 mg/kg
IV/SC
0.2 mg/kg
SC
2 mg/kg SC
• Fluid Therapy - for crystalloids
Maintenance Fluid
Therapy (Dog)
Maintenance Fluid
Therapy (Cat)
132 x bw(kg) 0.75 = maintenance
for 24 hours
80 x bw(kg) 0.75 = maintenance
for 24 hours
8

DRUGS AND FLUIDS
Drug
Concentration
Dosage
• Synthetic Colloids
Hetastarch (Dog)
Hetastarch (Cat)
VetStarch
Gelatin-Based
Colloids
5-10 ml/kg IV over 15-30 min
(bolus) OR 10-20 ml/kg/day CRI
2.5-5 ml/kg IV over 15-30 min
(bolus) OR 5-10 ml/kg/day CRI
5-10 ml/kg IV (bolus) OR up to
20 ml/kg/day CRI
5-10 ml/kg IV over 15-30 min
Remember the maximum dose of synthetic colloids
over a 24 hour period is up to 20 mg/kg
• Natural Colloids (Blood Products)
Plasma
Cryoprecipitate
10-20 ml/kg IV over 4 hours
1 unit/10 kg IV
9

Blood Product
Administration Considerations
• Crossmatching:
Required for cats and for dogs with prior
transfusions.
• Rate of Administration:
Start slow (0.5 ml/kg/hr for first 15-30
min), then increase if no reaction.
• Monitoring:
Watch for transfusion reactions
(tachycardia, fever, vomiting,
haemolysis).
• Filter Use:
Always use a blood filter (170-260
microns) for blood products.
10

DRUGS AND FLUIDS
Drug
Concentration
Dosage
• CPCR - also used in cardiac arrest*
Adrenaline
Atropine
Vasopressin
1 mg/ml
0.6mg/ml
20 IU/ml
0.01 mg per Kg
0.05 mg/kg
0.8 IU/kg
*See anti Arrhythmic drugs and reversals
** IU (International Units)
This RECOVER 2024 CPR Algorithm,
developed by our partners at RECOVER,
is an evidence-based guide to improving
survival in dogs and cats through
high-quality compressions, ventilation,
and rhythm-based treatment.
RECOVER CPR Algorithm
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Drugs and equipment to set up
before any anaesthetic:
• Endotracheal tubes
• IV catheters, t-connector,
flushing saline
• Laryngoscope checked
• Lidocaine
• Stylet
• Suction checked
• Heat support
• Emergency adrenaline
• Reversals (Atipamezole / Naloxone
/ Butorphanol) calculate
• Atropine
• Isotonic crystalloids
• CPCR algorithm available
• Fluid administration set
12

Cuff Inflation
Cuff pressure can be measured using
a manometer or a digital cuff inflator
syringe (AG Cuffill; Figure 1) to inflate
and measure the cuff pressure, which
should be 20 to 30cmH 2
O
(Hung et al., 2020).
Figure 1 - AG Cuffill
A different type of cuff inflation syringe
(Tru-Cuff) contains a colour-coded
pressure indicator.
13

Other approaches:
Minimum occlusive volume (MOV)
technique for cuff inflation, which
involves two people.
` One person manually inflates the
chest by squeezing the reservoir bag
with a closed APL valve to a peak
airway pressure of 20cmH 2
O.
` The other listens for an air leak
around the ETT (Hung et al., 2020).
` The cuff is gradually inflated until
the leak disappears.
` Digital palpation of the pilot valve
after cuff inflation should be avoided
as this technique is inaccurate
to assess correct inflation
(White et al., 2017).
HV/LP cuffs and those not fully deflated may be more
difficult to place through the larynx, particularly in
cats. Brachycephalic breeds of dogs have relatively
narrow tracheas compared to their body size, so
tubes with a narrower diameter are often required.
14

Endotracheal Tubes
Sizing based on ideal weight
• Cats
1
3
3.5
4
2
3.5
4
4.5
• Dogs
2
5
14
8.5
3.5
5.5
16
9
4.5
6
18
9.5
6
6.5
20
10
8
7
25
11
10
7.5
30
12
12
8
40+
14-16
Weight (kg)
ET tube size (mm)
Make sure to also have 1 tube above and 1 tube below
the estimate of your sizing as a precaution.
15

Anaesthetic Machine
` Primary Oxygen Source Checked
` Back-up Oxygen Available
` Oxygen Alarm Working
` Flowmeters Working
` Vaporiser Attached and Full
` Anaesthesia Machine Leak Tested
` Scavenging Checked
` Monitoring Equipment Functioning
` Emergency Equipment and Drugs Checked
` Pop off valve open unless using ventilator
Reservoir Bag
Reservoir bag volume = 3 - 6 x tidal volume
for a rough guide, use this table below.
0-4.5 Kg
4.6 - 9 Kg
9.1 - 27.2 Kg
27.3 - 54.4 Kg
Weight (kg)
½ Litre
1 Litre
2 Litre
3 Litre
Bag size
16

Peri-Op Prep
• Non-Rebreathing System
< 3 Kg
3 – 10 Kg
Ayre’s T Piece
Mod Jackson-Rees
Bain
Ayre’s T Piece
Mod Jackson-Rees
Bain
Paediatric circle
(not pediatric universal F)
• Rebreathing System
10 – 20 Kg
> 20 Kg
Adult circle
Adult universal F
(not if ETT is >9.5mm)
Adult circle
Weight (kg)
Breathing Circuit
17

Calculating fresh gas flow
for non rebreathing system
→ Fresh gas flow = minute volume x
body weight (kg) x “circuit factor”
→ Circuit factor for Lack and Mini Lack
= 1-1.5
→ Circuit factor for Bain, Map D T-piece
and Ayre’s T-piece with Jackson Rees
modification = 2.5-3
Minute volume = respiratory rate
x tidal volume but in small animals
can be estimated to:
• Small dogs / cats/ rabbits = 250 ml/
kg/min
• Average dog = 200 ml/kg/min
• Large dog = 150 ml/kg/min
NB After starting at this high fresh gas flow, remember
to use your capnograph to reduce your FGF until you
just see rebreathing.
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Calculating fresh gas flow
for circle system
→ Start at anaesthesia at 2L/min fresh
gas flow for 10 minutes.
→ Calculate 10ml/kg/min (this
represents metabolic oxygen demand
(MOD))
→ Turn fresh gas flow down to a
minimum of 0.5L/min (assuming this
is greater than MOD for the patient)
with the APL valve open.
→ If patient is heavier than 50kg (which
would equate to a MOD of 0.5L/min)
then use 1L/min as your fresh gas
flow.
19

Normal Vital Signs Under
Anaesthesia
• Large Dog (25–40 kg)
60–100 bpm
• Medium Dog (10–25 kg)
80–120 bpm
• Small dog (Under 10 kg)
70-180bpm
• Cat HR
90-200bpm (depending on life stage)
• Resp Rate
Dogs (Medium to Large breed):
8-12 breaths/min
Small dogs:
10-18 breaths/min
Cats:
10-20 breaths/min
20

NORMAL VITAL SIGNS UNDER ANAESTHESIA
• SPO2
>95%
• MM colour
Pink
• CRT
1-2 sec
• ETCO 2
35-45mmHg
• Systolic BP
Minimum 80-90 mmHg
• Temp
36-38°C (depending on patient,
species and life stage)
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ET C0 2
Zero
` Apnoea
` Disconnected ET tube
` Oesophageal intubation
` Cardiac arrest
Low (Hyperventilation)
` Sudden decrease can happen
with low cardiac output
` Check for a leak
` Too light under anaesthesia
High (Hypoventilation)
` Occurs more in obese patients
` Excessive dead space
` Rebreathing (increase fresh gas flow
in a non-rebreathing circuit
` Exhausted soda lime
` Malfunctioning one-way valves
` Too deep
22

Intra-Op Monitoring
Light Anaesthesia:
` Central eye position
` Swallowing, muscle twitching,
purposeful movements
` Increase in heart and RR with
or without brisk palpebral reflex
Moderate Anaesthesia:
` Ventral rotation of eyeball
` Loose jaw tone
Deep Anaesthesia:
` Muscle relaxation and loss of jaw tone
` Central eye position
` No corneal reflex
23

Intervention
Excessive Depth
` Decrease anaesthetic volatile agent
flow rate
` Increase IV fluid rate/provide boluses
as needed to raise BP
` Provide additional heat support
Bradycardia
` Administer glycopyrrolate 5-10 mcg/kg IV
` Determine possible cause
` Most common are drug induced
(anaesthetic gas. narcotics).
` Reduce anaesthetic gas. may need to
reverse medications: Naloxone, Flumazenil
(Depending on if opioids previously used)
Tachycardia
` Check what surgeon is doing!
` Check swabs, and suction for amount
of possible blood loss
` Might be insufficient anaesthetic depth:
Increase gas
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INTERVENTION
` Patient might be experiencing pain:
add opioid
` Check for hypotension
` Blood loss - to the end of hypotension
Hypertension
` Check correct cuff size
` Evaluate anaesthetic depth
` Address analgesia
Hypotension
` Check correct cuff size and placement
` Check heart rate
` Check body temperature
` Decrease volatile agent if possible
` Try 3 - 5 mg/kg bolus if appropriate
` Repeat fluid bolus
` If not resolved, consider using
Sympathomimetics: Dopamine: 2-10 mcg/
kg/min, Dobutamine: Cat: 1-5 mcg/kg/min
/ Dog: 1-10 mcg/kg/min, Ephedrine: 0.05-
0.1mg/kg IV
25

Capnogram waveform
changes
Normal Trace
Cardiac Oscillations
26

CAPNOGRAM WAVEFORM CHANGES
Cardiopulmonary Arrest
Hyperventilation
Return of spontaneous circulation
27

CAPNOGRAM WAVEFORM CHANGES
Hypoventilation
Hypocapnia
Rebreathing CO2
28

CAPNOGRAM WAVEFORM CHANGES
Expiratory Resistance
Inspiratory Resistance
29

ECG
Connecting the ECG
In small animals
` Red: Right forelimb
` Yellow: Left forelimb
` Black/green: Left hindlimb
In horses a base apex configuration is used:
` Red: Jugular furrow
` Yellow: Sternum
` Black: Ribcage
The direction of how the electrical
impulse is read is based on what lead
the ECG is reading. Lead Il is the most
commonly read lead in veterinary
anaesthesia.
` Lead I: right forelimb to left forelimb.
` Lead II: right forelimb to left hindlimb.
` Lead III: left forelimb to left hindlimb.
30

A labelled
electrocardiogram
(ECG) trace
R
P
T
PR
Q
QRS
S
QT
31

A LABELLED ELECTROCARDIOGRAM (ECG) TRACE
The P wave is generated from the atria,
when the electrical impulse moves
from the sinoatrial node (SA node,
the pacemaker) to the atrioventricular
node (AV node). The QRS complex
occurs when the electrical impulse
moves through the ventricles, down
the bundle of His and up the Purkinje
fibers. Understanding how the P and the
QRS are formed, helps troubleshoot any
abnormal complexes or arrhythmias.
It is worth recognising that an ECG can
double count the T and QRS waves
giving an inaccurate heart rate value,
therefore heart rate should be counted
from pulse palpation or auscultation
rather than relying on the ECG.
32

Understanding Pulse
Oximetry Waveforms:
• Normal Waveform:
A smooth, regular pattern indicating
consistent blood flow and oxygenation.
• Low Amplitude Waveform:
Smaller waves that may suggest
hypotension or poor peripheral
perfusion.
• Irregular Waveform:
Inconsistent patterns potentially caused
by arrhythmias or patient movement.
33

PULSE OXIMETRY WAVEFORMS
Normal Signal
Low Perfusion
Noise Artifact
Motion Artifact
34

Anaesthesia Equations
1. Drug Dose Calculation
To calculate the amount
of drug to administer:
Dose (mg) = Weight (kg) × Dosage (mg/kg)
2. Volume to Administer
To calculate the volume
of drug to draw up:
Volume (mL) =
Dose (mg) ÷ Concentration (mg/mL)
3. Anaesthesia Fluid Rate
To calculate a higher rate
during surgery:
Dogs: 5kg/hr
Cats: 3–5 mL/kg/hr
Rate (mL/hr) = Weight (kg) × Anaesthesia
Fluid Rate (mL/kg/hr)
35

ANAESTHESIA EQUATIONS
4. Haematocrit/PCV Replacement
To work out how to correct for
surgical blood loss:
Dogs: 90 mL/kg
Cats: 56 mL/kg
Add up blood volume lost in suction and
swabs (after deducting flush and dry
swab weight)
%blood volume lost = volume of blood lost /
animal’s blood volume x100
5. Patient blood volume
10-15% blood volume lost =
replace with 3 x volume in crystalloid
15-20% blood volume lost =
replace with 1-1.5 x volume in colloid
>20% blood volume lost =
replace with 1-1.5 x volume in blood product
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