ECP 2 Flashcards
1
Q
Define:
Sepsis
Asepsis
Antisepsis
A
- Sepsis: The presence of pathogens (or their toxins) in the tissues.
- Asepsis: The absence of pathogenic microorganisms in living tissue.
- Antisepsis: Prevention of sepsis by the destruction or inhibition of microorganisms.
2
Q
Define antiseptic, disinfectant and sterilization
A
- Antiseptic: A chemical agent that either kills pathogenic microorganisms or inhibits their growth. (Applied to patient)
- Disinfectant: A germicidal chemical substance that kills microorganisms on inanimate objects. The term disinfectant is reserved for agents that are not applied to the body. Not as effective as sterilization.
- Sterilization: Is the complete elimination of microbial viability, including vegetative forms of bacteria and spores
3
Q
post-operative infections what is the new challenge and main problems
A
- New challenges - Methicillin-resistant Staphylococcus aureus (MRSA), Methicillin-resistant Pseudintermedius (MRSP)
- Increases the morbidity of procedure outcomes, prolongs hospitalisation times and increases costs to the client.
- Particularly for orthopaedic procedures -> increased time for surgery and recovery
- Adverse publicity -> can ruin a clinic
4
Q
What are the 4 sources of contamination during surgery
A
- The patient – main source
a. Skin
b. Haematogenous - The surgical equipment and implanted biomaterials (sutures, plates, screws etc)
- Surgical personnel
- The operating theatre environment, including airborne particles.
5
Q
What are the 4 non-sterile barriers and 3 sterile barriers
A
NON-STERILE BARRIERS 1. Scrub suits 2. Surgical head covers 3. Face masks 4. Shoes and shoes covers STERILE BARRIERS 1. Surgical gown 2. Sterile gloves - susceptible to tearing and punctures 3. Sterile drapes
6
Q
What are the 2 different types of surgical gowns and drapes
A
1) Reusable:
○ Typically woven 50/50 Polyester/cotton -> woven so have larger holes for bacteria
○ Holes need to be repaired via a heat sealed patch.
○ Should be treated to make them waterproof
2) Single use: - BEST OPTION
○ Synthetic - Non-woven
○ The use of disposable gowns decreases contamination and infection rates.
7
Q
What is the goal of surgical site preparation and the 6 considerations for a good antiseptic solution
A
- Whilst it isn’t physically possible to sterilize the skin of the patient, the intention should be to remove organic material and reduce bacterial contamination to as close to zero as possible and eliminate transient bacteria.
- Broad spectrum
- Ability to reduce growth on transient and resident microorganisms
- Be rapid and cumulative
- It should not create skin irritation
- It should have residual/persistent action
- TGA approved
8
Q
What are the 3 common antiseptics for skin preparation and their characteristics
A
1) Chlorhexidine gluconate
- G+/G- bacteria, viruses and fungi NOT sporicidal
- residual action (6 hours), not inactivated by organic materal, diluted in wounds 0.05%
- not compatible with iodine
2) Povidone-iodine
- bactericidal, fungicidal, virucidal may be sporicidal
- low residual activity, inactivated by organic material
- high incidence of skin reactions
3) alcohols
- ○ Most RAPID and effective antibacterial antiseptic (including MRSA & MRSP)
○ Bactericidal, fungicidal, variable against viruses and ineffective against spores.
○ Most effective at 70%
○ Evaporates very quickly - minimal residual effect so never used ALONE
○ Tissue necrosis in open wounds
9
Q
Hair removal for surgery preparation what is important
A
- skin trauma increases bacterial counts
- size 40 clippers
- hair removed in wide margins
- with the grain and then against
10
Q
What are the 3 key steps
A
- Pre-Wash (using a detergent based antiseptic) - chlorhexidine or Povidone-iodine
- Removal of the detergent (using 70% alcohol)
- Application of an approved surgical skin antiseptic product.
11
Q
What are the 3 main aims of surgical hand scrub
A
- To remove dirt, flaking skin, oil and microorganisms from the hands and lower arms (below the elbow).
- To reduce the microbial count (residential & transient) to as close to zero as possible.
- To provide a prolonged inhibitory effect on the resident micro flora.
12
Q
What are the 2 types of hand scrubs and what is considered the best
A
- Traditional Water Based Hand Scrub
- ALCOHOL BASED HAND RUB (ABHR)
- Considered gold standard in surgical hand hygiene
- Applied to clean, dry hands and arms.
13
Q
What is the sterile zone on a gown and what is the only thing that can touch it
A
- The sterile zone
○ Mid chest level to waist level
○ From finger tips to elbows
Gloved hands should only touch the sterile zone!!!!
14
Q
Draping what is teh sequence and how to drape a limb
A
- Near, top, tail and far sequence, followed by the large cover drape (fenestrated or nonfenestrated) - learn order
- Free draping
○ When whole limb is required to be within the sterile field
○ Paw bandaged and suspended
○ Paw bandage wrapped with:
§ Sterile Vetrap and waterproof glove
§ Sterile waterproof drape
15
Q
What is the most important thing in terms of theatre etiquette and the order to process and sterilise instruments
A
- Direct correlation between the number of people, their movements and the number of airborne bacteria in the operating theatre.
- Work flow should encourage separate processing, from cleaning dirty instruments, instrument packaging, sterilizing, then storage.
16
Q
sealing and labelling instruments before autoclaving what is involved
A
- Sealing: ○ Autoclave tape ○ Heat sealing: for paper bags and laminates - Labelling ○ Not ball point pens ○ Not on paper packaging ○ Include the following information: § Date of sterilization § Expiry date § Instrument type Staff member initials
17
Q
List 6 methods of sterilization
A
- Gas Plasma - Hydrogen peroxide vapour and low temperature (42°C) – aka “Sterrad” system
- Gamma irradiation - Radioactive isotope Cobalt 60
- Ethylene oxide gas
- Peracetic acid aka Steris System
- Elevated temperature in dry heat oven (160-180°C)
- Steam under pressure - Autoclave (common in veterinary practice)
18
Q
Autoclaves why used, and how works
A
- Steam sterilizers are cheap to run, non-toxic, safe and simple to use.
- Pressure vessels (autoclaves or steam sterilizers) are used to achieve high temperatures with dry saturated steam.
○ Dry saturated steam refers to steam that doesn’t produce water droplets and the condensate is in equal balance with evaporation.
19
Q
What is shelf life related to
A
- Shelf life is dependent on external events that compromise the integrity of the protective barrier of the sterilized item, such as choice of packaging material, correct sterilization process, handling and storage, rather than a given time frame. Therefore, shelf life is event related not time related.
20
Q
What is the most common towel clamp, what used for and is it used at melbourne uni
A
- Used to secure linen drapes to patient skin.
- Backhaus towel clamps most common.
- Not used for single use, disposable drapes so not used at Melbourne
21
Q
What are the 6 suture material characteristics
A
- Tensile strength – load at which suture fails
- Capillarity - wicking of fluid along structure
- Mechanical creep/stress relaxation – slowly deforms under constant stress
- Plasticity - deformation under load, then reverts
- Pliability – ability of suture to change shape
- Suture pull out value – load required to pull suture out of tissue
22
Q
Monofilament vs multifilament what are the advantages and disadvantages and which is preferred
A
Monofilament: preferred - Less pliable - Poorer handling, increased memory - Less tissue drag - Less knot security, more knots required. Multifilament: - Greater strength and pliability - Improved handling compared to monofilament - Increased capillarity - Increased tendency for bacterial colonization - Avoid in contaminated environments - Greater tissue drag - Increased knot security
23
Q
What makes a suture absorable and what is the purpose of sutures
A
Absorbable are those that absorb within body tissue under 120 days and do not require removal, whilst nonabsorbable sutures retain their strength until they are removed.
- The common purpose of sutures; are to stop bleeding and/or to pull together wound edges to allow healing of damaged tissue.
- An additional purpose in modern day surgery is the “stay suture”.
24
Q
What are the 2 most common monofilament and 1 multifilament sutures and their properties
A
PDS, PDS II – synthetic, absorbable, general closure, significant memory - GO TO MOST COMMON Monocryl – synthetic absorbable, similar to Biosyn.
Multifilament
1. Catgut – absorbable, excessive tissue reaction. Better suture available.
25
Suture size what is it measured in, the reference range, what choose for small patients and which thicker and thiner diameter
- United State pharmacopeia (USP)
○ 11/0 to 7
○ For small animal patients, typically sizes 4/0 (finer) to 0 (thicker diameter)
○ USP most commonly used in Australia
- Metric
○ suture diameter expressed in 10th’s of a millimeter
26
Suture needles what makes the ideal ne and the 2 types with properties
- Ideal surgical needle – sharp enough to penetrate with minimal resistance, slim without compromising strength, resistant to bending but flexible enough to resist breaking
1) Eyed - resusable, increased tissue damage (blunt needle) - not recommended
2) swaged on - USE THIS ONE, single use, cause less tissue trauma (shrap needle), essential for suturing delicate tissue
27
What are the 4 different needle shapes
- Straight - Placed by hand in skin
- Curved - defined by fraction, ½, 3/8, ¼
- Half curved – used to be very popular
- Half circle – currently the most popular shape for many circumstances (available in a multitude of sizes)
28
Suture needle points what are the 2 main ones, what used for and 3 types within
1) Blunt & Taper Point (round bodied) - Used in friable and delicate tissue (GIT, liver, muscle)
2) Cutting - Used in tough tissue (e.g. skin, periosteum, fascia)
1. Conventional cutting
○ Cutting surface on concave surface
○ Increased risk of cut out so need larger suture diameter
2. Reverse cutting
○ Cutting surface on convex side § Preferred as less cut out
3) Tapercut
○ Compromise between round and cutting needle
○ Fine point: used in delicate tissue
○ Reverse cutting tip and tapered body
○ Greater penetration compared with taper but less cutting compared with reverse cutting
29
What are the 4 main considerations when selecting a suture material
1) suture as strong as tissue placed within
2) rate at which suture lose strength and tissue heals compatible
- For rapidly healing tissues like bladder or stomach, a short acting absorbable is appropriate.
- For slow healing tissues e.g. fascia (poor blood supply) a long acting absorbable is appropriate.
3) biological effect of suture not abraided in GIT
4) appropriate size commensurate with the tissue
30
What occurs in terms of wound strength after surgery and tensile strength
- Wound strength reliant on sutures for first 3-5 days - CONFINED FOR 7 DAYS
- The most rapid gain in wound strength is between 7 and 14 days after injury
- Wounds never attain the tensile strength of normal tissue - at maximum strength a scar is only 70% to 80% as strong as normal tissue.
31
What are the 5 main knots and how long should tags be in syntehetic and catgut
1. Simple - 1 throw
2. Square knot - 2 throws, revising direction with each throw
3. Surgeons knot - only when tissue won't come together easily
4. Granny knot - DON'T WANT, 2 single throws without reversing direction
5. Sliding (slip) knot - uneven tension applied to square knot
Tags should be 3mm long for synthetic and 6mm for catgut
32
Interupted and continuous suture patterns contrast and the 2 main types of each
INTERRUPTED SUTURE PATTERNS
- Allow more precise wound margin apposition and adjustment of tension
- Closure security improved
- Slower, more foreign material
- Skin sutures should not be tied too tightly
Types
1) Appositional patterns
2) Simple interrupted
CONTINUOUS SUTURE PATTERNS
- Quicker
- Greater suture economy
- Distribute tension more evenly – appositional
- Reduced closure security c/w interrupted
Types
1) Simple continuous - appositional
2) Ford interlocking (blanket stitch) - greater tissue stability than simple continuous
33
What are 4 main problems with haemorrhage
- Severe haemorrhage leads to hypotensive shock
- Bleeding obscures the operative field
- Blood within the operative field irritates tissue, prevents tissue apposition, delays healing and potentiates infection
- Blood on instruments, drapes and tissues is an ideal medium for bacterial growth
34
What are the 4 main methods of haemostasis and describe
1. Pressure/Tamponade - use a gauze swab, for definitive haemostasis need to hold for 4 mins
2. Hypothermia – causes vasoconstriction
3. Ligation - use of suture materials - increased application time
4. Electrosurgery - electric prongs (electrocoagulation) - can lead to a fire risk
○ Leads to damage so shouldn't be used close to vital structures, longer healing times
○ Vessel sealing devices -> used up to 1mm arteries and 2mm veins
35
What does contrast studies provide and what are positive and negative contrast agents
- provides additional morphologic and functional information to assist diagnosis and treatment planning
Positive contrast agents are radiopaque (white)
Negative contrast agents are radiolucent (dark)
36
What are some examples of negative contrast agents and what are they used for
Negative contrast agents are room air, carbon dioxide, or nitrous oxide
- Negative contrast agents are used to inflate hollow organs
37
What is a contrast study called in the 1) urinary bladder 2) colon 3) stomach
urinary bladder = pneumocystogram
colon = pneumocolon
stomach = pneumogastrogram
38
What is the problem when performing a pneumocystogram in patients with haematuria and how to reduce this
Risk of air embolism
- Place patient in LEFT lateral recumbency to minimise the risk of death
○ Introduce gas, gas will move into right ventricle and absorbed overtime, will not move into pulmonary vessels
Use CO2 or NO more soluble than room air - not really done
39
What are the characteristics of positive contrast agents and the 2 main examples
Positive contrast agents have high atomic number and are efficient absorbers of x-rays
1) Barium
2) Iodinated contrast
40
Barium what is it, used for and 3 types what used for
positive contrast agent
- is used to image the gastrointestinal tract (preferred), excreted via faeces as not absorbed
1) Liquid barium coats mucosa and objects and is preferred to outline lesions - iodinated won't stick to the wall
2) BIPS (gel capsule - barium coated spheres within) may be used to rule out a complete GI obstruction but have little use beyond this
○ Doesn't coat the mucosa so cannot see the lining of the GIT
3) Barium within food may be used for oesophageal contrast studies BUT NOT IF THERE IS A PERFORATION
41
What are the 3 main issues with using barium
1) Barium MUST NOT be placed intravenously or intrathecally - ONLY USED IN THE GI TRACT -
- If aspirated, it may occlude the airways, or may simply be taken up by macrophages -> not too much of an issue
2) Outside the GIT barium is irritant
○ If perforation is suspected use iodinated contrast agent
3) Clogs up endoscopes so if endoscopy is planned used iodinated contrast agent instead OR do Endoscopy FIRST
42
Iodinated contrast what is it, used for and how excreted
positive contrast agent
- Used intravenously and intrathecally, can be used in hallow organs such as GIT and Urinary tract - used for cystocentesis and excretory urograms
- Based on benzene ring, may become a negative ion in solution or may be non-ionic
- Excreted via the kidneys, to determine whether toxic effects may occur do urinalysis (kidney) and biochemistry (kidney/liver)
43
What are the 4 main negative effects of iodinated contrast, which type is safer and which use in myelogram
Intravenous injection may cause
1. Hypotension -> from osmolarity change -> haemodynamic effects -> local and generalised vasodilation
2. Nephrotoxicity
3. Thrombosis -> change in osmolarity leading to increase capillary permeability -> thrombosis
4. Idiosyncratic allergic reactions
For a myelogram ONLY use non-ionic iodinated contrast agents
Non-ionic iodinated contrast agents are safer: less risk of adverse reactions - only use
- Ionic iodinated agents dissociate in solution so are hyperosmolar relative to blood - THIS CAUSES THE ISSUES
44
Radiographic descriptions what are the 2 main rules
1. Radiographic projections should be named using only proper veterinary anatomic directional terms
2. Radiographic projections should be described by the direction that the central ray of the primary beam penetrates the body part of interest, from point of entrance to point of exit
45
Left/right marker in x-rays what can they indicate
- May indicated side of the body or side that is down (lateral)
- Or may indicate the side of the limb
- For distal limb the L/R marker should be placed on the LATERAL aspect of the limb - ESPECIALLY FOR HORSES
46
What are the 3 main hanging protocols for the body
○ VD/DV head to top, viewed from belly -> right always on your left hand side
○ Lateral: dorsal to top, running to your left
○ CC or DP: proximal to top, lateral to your left
47
What are the 4 parts of the radiographic report
- Description
- Radiographic Diagnosis
- Differential Diagnoses
- Recommendations
48
Image interpretation what is involved and what are the 2 components to radiographic interpretation
Image interpretation
- Dependent on observational skills
- Tempered by your visual perception of those observations
- Depends on surrounding visual information
- Trick of the eye
- Interpretations should always be made in light of clinical information, to help avoid inattentional blindness
There are two components to radiographic interpretation:
1. Perceptual - Observing the lesion
2. Cognitive - Knowing what is means
49
In Pain assessment what are the main things you look for in animals
- Demeanour
- Posture
- Vocalisation
- Attention to wound
- Mobility
- Interaction with people
- Interaction with peers
- Response to handling
Others signs - affected by medication and pathological processes
- Heart rate
- Respiratory rate
- Pupil dilation
50
What are the 4 main pain assessment tools and describe them
1. Simple Descriptive Scales (SDS) -> describe intensity of pain, 4-5 expressions, not very sensitive
2. Numerical Rating Scale (NRS) -> numerical score 1 to 10, better but not as sensitive
3. Visual Analogue Scales (VAS) -> pain on a scale (10cm line), more sensitive but still subjective
4. Multifactorial Pain Scales (MFPS)
- Generally more precise than the other pain scales
- Composite of a number of SDS
○ Relating to particular aspects of behaviour associated with pain
- May be pictorial in characterization of species specific pain behaviour/demeanour
- May also have a physiological component to assessment.
51
For dogs and cats what are the main pain scales with acute and chronic pain
```
In dogs
- For acute pain
○ Glasgow Pain Scale - use here
○ Melbourne scale
- For Chronic pain
○ Helsinki Pain Scale (vet vs. owner)
In Cats
- For acute pain
○ Glasgow Feline Composite Measure Pain Scale - clinical use
○ UNSP-Botucatu MDPS - better for research as takes 15-20mins
- For chronic pain
○ Quality of life questionnaire
```
52
What are the 3 levels of differences in assessing clinical pain
```
1. Altered environment
○ Animal will mask signs of pain
○ Animal will be apprehensive, excited, aggressive,…
○ Herd animals stressed when separated
○ Presence of owners
○ Presence of other species
2. Species differences
○ “normal” comportment for given species
○ Reaction to pain between species
§ Horse colic vs. cat hit by a car
3. Within species differences
- Individual animal might react differently
○ Labrador vs. greyhound
```
53
Chronic pain in small animals what are the 3 important facts and 3 signs of chronic pain
- insidious onset
○ subtle changes over a long time
- external signs of disease may not be present
- often older animals
○ owners associate changes with growing old
Signs of chronic pain
- behavioural changes
○ depression, sleep disturbance, irritability aggression, social withdrawal, ↓ appetite, ↓ interest in exercise, loss of playfulness
- reduced mobility
○ stiffness, lameness
- lick granulomata etc
Sometimes improvement seen after pain relief that highlights problem
54
List 7 treatments for chronic pain therapy
1. oral opioids -> can lead to sedation
2. Transdermal fentanyl
3. NMDA antagonist
4. Mood-altering drugs
○ TCADs, MAOIs, BZPs
5. NSAIDs - Important for inflammatory process
6. acupuncture analgesia
7. Physiotherapy
55
Define anesthesia, analgesia and pain
Anaesthesia - is a reversible pharmacologically induced state of loss of sensation (including pain)
Analgesia - decrease or absence of pain (only sensation that you are losing)
Pain - conscious perception of a noxious stimuli
56
What is local and regional anaesthesia
1) Local anaesthesia: loss of sensation in a circumscribe body area (e.e.: toe).
- Achieved by blocking specific terminal nerves using local anaesthetics.
2) Regional anaesthesia: loss of sensation in a more extended body area (e.e.: limb).
- Achieved by blocking major nerves or multiple terminal nerves using local anaesthetics or analgesic drugs.
57
What is general anaesthesia and sedation
1) General anaesthesia: pharmacologically induced state of absence of consciousness; the patient will not respond to any stimuli, including pain.
- It is achieved by administering intravenous anaesthetics or inhalant (breathing in) anaesthetics
2) Sedation: pharmacologically induced state of reduced level of consciousness
- May be associated with a lack of memory.
- When combined with analgesic, there is also a reduce level of pain perception.
58
What needs to be involved with a premedication and give an example of a good one
In practice general anaesthesia should always be combined with analgesia and muscle relaxation
Acepromazine (sedation), hydromorphone (opioid analgesia), midazolam (good muscle relaxation), Propofol (anaesthesia) - this one
59
What are the 4 stages of general anaesthesia
Stage I - Disordered consciousness, voluntary movement
Stage II – Excitement
Stage III - Surgical Anaesthesia
Stage IV - Overdose
60
Describe stage I and Stage II of anaesthesia
Stage I
- Stage I - Disordered consciousness, voluntary movement-
- The first action of an anaesthetic on the cerebral cortex is to render its functions more acute but unbalanced (except for pain perception)
Stage II - Excitement
- Unconsciousness
- May be unnoticeable in cases where heavy premedication or basal narcosis has been employed.
61
Stage III of anaesthesia what is the goal, what are the planes within, which one want and signs
- Stage III - Surgical Anaesthesia
- Tranquil phase of narcosis which resembles natural sleep.
- Goal: maintain the level of narcosis within this stage as required by the nature of the intervention.
- 4 planes
○ Light Medium, deep
○ Plane 2 -> what we are looking for
§ Eye ventro-medial, decrease respiratory rate, palpebral reflex absent, corneal reflex present, relax jaw tone
62
Stage IV of anaesthesia what is the major issue and 4 main problems
- Signs of severe shock (shock - not able to deliver enough oxygen for demand)
- Weak pulse, not breathing
- Dilated pupils
- Reflexes are absent
Lost control of sphincter tones
63
Pre-anaesthetic patient evaluation what to include
- History
- Physical exam
- Pain assessment
- Clinical diagnostics
- Other considerations
- Classification of physical status (ASA status)
64
What is involved with physical exams for pre-anaesthetic patient evaluation
- Touch your patient
- Auscult heart/feel pulses
- Auscult lungs
- MM/CRT
- Temperature
- Palpate abdomen
- Brief neurologic exam
65
What are the main issues with pain and anaesthesia
- Pain increases dosage of anaesthetics needed => more side effect
- Pain causes patient stress and reduces healing
○ Prophylactic Treatment of pain:
○ Reduces dose needed
○ Minimize Wind-up and hyperalgesia
○ Will be synergistic with your pre-meds
66
What are some clinical diagnositcs that can be done in pre-anaesthesia patient examination
- CBC / Chemistry (minimum PCV/TS/BUN/B.G.)
- Heartworm
- Thyroid function
- Coagulation
- RX - radiograph of the chest -> murmur -> check the heart size to consider whether cardiovascular disease
- Echo -> if has cardiovascular disease changes on the radiograph
67
Pre-anaesthesia patient preparation what are the 2 important considerations and why
1) Fasting, minimal water deprivation
○ Recommended in most patients
○ Anaesthetics relax the lower oesophageal sphincter and ↓ GI motility
§ Risk of regurgitation and aspiration
§ Risk of bloat
§ Risk of ileus → very uncomfortable post-op!
- No fast in case of emergency => secure airway quickly
2) Water is provided until just before procedure!
68
Body fluid compartments what percentage is water and dry matter and what is the difference between hypoperfused and dehydration in terms of emergency
- Total body water (TBW) = 60% of bodyweight
- Dry matter = 40% of bodyweight
Interstitial dehydrated - not hypo-perfused yet up to the 10%
Interstitial dehydration isn't emergency but hypo-perfused is, can move from dehydration - hypoperfused or may just jump straight to emergency
69
List the 3 approaches to fluid therapy and generally when to use
1. Acute resuscitative fluid therapy
○ Correction of hypoperfusion (INTRAVASCULAR deficit)
○ Rapid intravenous fluid therapy targeting restoration of perfusion - within an hour or 2
2. Rehydration fluid therapy
○ Correction of dehydration (INTERSTITIAL or INTRACELLULAR deficit)
○ Generally replaced over 4-24 hours
3. Maintenance fluid therapy
○ Used for animals with normal perfusion and hydration that can’t or won’t take in fluids
○ Maintenance rates = rates needed to maintain zero fluid balance (equal to energy requirements)
70
Maintenance fluid therapy what do you need to take into consideration and what occurs with
○ Takes into consideration sensible and insensible losses
§ Sensible losses (losses that one can ‘sense;) –Urine
§ Insensible losses –Evaporative (cutaneous, respiratory), faeces, saliva
○ + Ongoing losses (egpolyuria, vomiting, diarrhea)
○ Generally occurs with approach 1 or 2 as generally not drinking at that time
71
What are the percentages in terms of body water within the body
Total Body Water = 60% of BW (kg)
- ICF (intracellular fluid) = 67% of Total body water
- ECF (extracellular fluid) = 33% of Total Body water
○ Interstitial - 75% of ECF
○ Intravascular - 25% of ECF
Total blood volume (dogs) = 25% of 33% of 60% = about 8% BW or 80ml/kg Cats about 60ml/kg
72
What are the 3 important things your body does to maintain perfusion and what occurs when they fail
- RAAS - renin, angiotensin, aldosterone, system - in kidney
- Drive to drink
- ADH - responds to increase sodium and decrease in blood volume
When they fail
- High levels of sodium result in movement from the intracellular fluid space into the extracellular fluid
○ DO NOT WANT TO HAPPEN - when you go into shock
73
How do fluids move within and between the extracellular and intracellular space and what makes it move
Extracellular space - think of as one compartment -> when give fluids rapidly redistributes throughout interstitium and vascular system
Intracellular space - freely permeable to water but not solutes -> membrane pumps control movement of ions
- Based on differences of osmolarity of the extracellular and intracellular water will move in or out of intracellular
74
If hypotonic or isotonic solution is given or lost what happens in terms of fluid movement
Hypotonic solution -> from extracellular to intracellular
- If lose hypotonic solution get higher solute concentration in ECF so fluid moves from intracellular to extracellular space
Isotonic solution -> no net movement of water
- Loss of blood (loss of isotonic solution) -> no change in tonicity between so no net movement of water THEREFORE will Hypoperfused faster as extracellular fluid is lost without intracellular fluid moving to stop this deficit
75
If hypertonic solution is given or lost what happens in terms of fluid movement
Hypertonic solution -> from intracellular to extracellular
- If lose hypertonic solution results in higher solute concentration in ECF than movement from extracellular into intracellular as well as loss from extracellular externally -> VERY FAST HYPOPERFUSION (SHOCK) occurs in intravascular space - WORST CASE
○ Eg -> burn patients -> lose high solute solution
76
Define tonicity and osmolality, what contributes to osmolaity and the normal for dogs and cats, osmolality and osmolarity
Tonicity
- the effect of a particular solution in reference to movement across a semipermeable membrane (i.e. the effective osmolality)
Osmolality
- a measurable property of a solution (independent of the effect across a membrane)
- ECF osmolality (mOsm/kg) = 2([Na+] + [K+]) + Glucose + BUN
- Normal: Dogs -300 mOsm/kg; Cats -310 mOsm/kg -> most of it is made of Na+
○ (Osmolality –moles solute / kg solvent)
○ (Osmolarity–moles solute / L solvent)
77
What are the 6 important questions for fluid therapy
1. Which approach?
2. How much?
3. How fast?
4. What route?
5. What type?
6. Any risk factors for developing complications?
78
What are the 3 steps in re hydration and maintenance fluid plans and equations
```
Hourly rate = deficit + maintenance
1) calculate the deficit
BW (kg) x %dehydration x 1000ml/L
2) Calculate maintenance requirements
2.5ml/kg/hr OR
- <2Kg or greater than 50Kg use different formula = (BW x 30) + 70
3) Estimate ongoing losses
- observe and replace over 4-6 hours
- when severe contemporary losses
```
79
How fast should your fluid plan be for rehydration and maintenance
- For rehydration(not in hypoperfused patients!), generally target 24 hours (range 6-24). Might depend on…
○ How fast they lost it
○ Practical considerations - 24 hour care at vet clinic?
○ Risk factors for developing complications of fluid therapy
ALWAYS REASSESS PATIENT AND ADJUST FLUID PLAN AS CLINICALLY INDICATED
80
What are the 4 routes that you can give fluids
1) intravenous
2) enteral (oral)
3) subcutanoues
4) intraoesseous
81
Intravenous route of giving IV fluids list the pros
○ Preferred route if acutely or severely ill - MANDITORY IF HYPOPERFUSED
○ Safe if vomiting or mentally altered (aspiration risk)
○ Provides rapid fluid dispersion of large volumes of fluid
○ Allows precision in administration of fluids and electrolytes
○ Hypotonic/hypertonic solutions can be administered via central vessels
○ More comfortable than IO catheters
82
Intravenous route of giving IV fluids list the 2 cons and the main complications
```
Cons:
○ Requires hospitalization (increased $$)
○ Flow can be positional
Complications: RARE
○ Phlebitis, Extravasation
○ Thrombosis (particularly concerning with central lines)
○ Catheter related infections/sepsis
○ Embolism (catheter, air)
○ Risk of volume overload
```
83
Enteral IV fluid route what is the main pro and 3 cons
Pros:
○ Low risk of volume overload, cheap
Cons:
○ May not be possible if patient is vomiting, regurgitating or has an altered mentation (risk of aspiration)
○ May not be able to administer sufficiently large volumes to correct significant deficits
○ NOT acceptable if patient is hypoperfused
84
Enteral IV fluid route what are the 3 main complications
Complications:
○ Aspiration
○ Inadequate intake
○ Complications associated with feeding tube placement
85
Subcutaneous IV fluid route what are the 3 main pros and cons
Pros:
○ Allows for outpatient treatment (reduced $$)
○ Can ensure a target volume is administered
○ Technically easy
Cons:
○ Limited by skin elasticity (easier in cats than dogs)
○ Can only administer isotonic fluids
○ Not adequate for severe dehydration or hypoperfusion
86
Subcutaneous IV fluid route complications
```
Complications:
○ Risk of abscessation(rare)
○ Risk if developing complications as once in cannot stop absorption
○ Patient intolerance/discomfort
○ *Risk of volume overload*
```
87
Administration of subcutaneous fluids where admister, how much per site
○ Between scapulae (or elsewhere if comfortable)
○ 10 ml/kg per site or as much as elasticity will comfortably allow
○ 50-200 ml for an average-sized cat depending on deficit
88
Intraoesseous (intramedullary) what are the 2 main pros and 3 main cons
Pros:
○ May be only option in very small patients
○ Allows rapid administration of large volumes of fluid
Cons:
○ Can be technically challenging
○ Painful –locally infuse lignocaine prior to placement
○ Requires hospitalization (increased $$)
89
Intraoesseous (intramedullary) complications and what generally used for
```
Complications:
○ Iatrogenic injury of regional nerves
○ Osteomyelitis
○ Risk of volume overload
- Generally used for acute resuscitative therapy until venous access can be achieved
```
90
What are the 2 types of fluids and describe them
1) Crystalloids
- Isotonic - MOST COMMON
○ Balanced–composition resembles ECF
○ Unbalanced –does not resemble ECF -> sodium chloride -> doesn't have all of the other electrolytes (Ca, K, Mg)
- Hypotonic, Hypertonic
2) Colloids - acute resuscitated
- Large-molecular weight fluids -> draw water and keep it there
- restricted to the plasma compartment in patients with an intact endothelium - DOESN'T CROSS UNLESS ISSUE - critical ill
○ Starches
○ Gelatins
○ Albumin/plasma
○ 20% Mannitol
91
Risk factors for developing complications of fluid therapy
- Heart disease
- Pulmonary disease
- Hypoalbuminemia
- Severe anemia
- Oligoanuricrenal failure
- Traumatic brain injury
- Vascular permeability
- Complex underlying disease (DKA, FUO, Addison’s)
- **Chronic or severe sodium derangements
92
chronic/severe hypernatraemia and hyponatraemia CNS effects and what to do with levels in terms of fluids
hypernatraemia
○ Rapid correction of ECF hyperosmolality -> cerebral oedema!!
○ DO NOT drop Na+ by > 0.5-1 mmol/hror > 12 mmol/24 hours
hyponatraemia
○ Rapid correction of ECF hypoosmolality -> neuron shrinkage!! (osmotic demyelination syndrome)
○ DO NOT increase Na+ by > 0.5-1 mmol/hror > 12 mmol/24 hours
