Lecture 4, pre- and postoperative care Flashcards

1
Q

Most common time of death related to anesthesia

A

Postoperative period

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2
Q

Why cats has 2 times higher risk for anesthesia-related mortality?

A

Smaller animal (hypothermia, overhydrating)

Uncooperative behaviour

Prone to laryngospasm

Sensitivity to local anesthesia drug toxicity

Reduced glucuronidation (slower drug metabolism)

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3
Q

ASA I, animals condition, examples

A

Healthy with no discernible disease

Patient is undergoing an elective
procedure (e.g.ovariohysterectomy, declaw, castration)

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4
Q

ASA II, animals condition, examples

A

Healthy with localized disease or mild systemic disease

Patellar luxation, skin tumor, cleft palate without aspiration pneumonia.

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5
Q

ASA III, animals condition, examples

A

Severe systemic disease

Pneumonia, fever, dehydration, heart murmur, anemia

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6
Q

ASA IV, animals condition, examples

A

Severe systemic disease that is life threatening

Heart failure, renal failure, hepatic failure, severe hypovolemia, severe hemorrhage

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7
Q

ASA V, animals condition, examples

A

Moribund; patient not expected to live longer than 24h with or without surgery

Endotoxic shock, multiorgan failure, severe trauma

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8
Q

Details that require attention in preoperative care

A
  • Thorough anamnesis
  • Full clinical examination
  • Laboratory data
  • Patient stabilization
  • Determination of surgical risk
  • Client communication
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9
Q

Preoperative care, anamnesis vitae

A

Basic information
- species
- breed (genetics, anatomy)
- age (diag. tests warranted?)
- gender

Lifestyle
- diet, exercise, environment

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10
Q

Preoperative care, anamnesis morbi

A

Reason for surgery (chief complaint)

Clinical signs and duration

Past medical problems and treatments

Current medical problems and treatments

Prior anesthesia
- used drugs, complications, recovery

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11
Q

Why it’s important to know the breed?

A

Breed has to be taken into consideration due to possible anatomical differences and other genetic predispositions

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12
Q

Brachycephalic breeds

A
  • Small hypoplastic trachea, elongated, soft palate, stenotic nares
  • Laryngeal mucous membrane prone to swelling
  • Increased tonus of n. vagus
  • Predisposition to gastroesophageal reflux
  • Higher risk of hypoxia
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13
Q

Toy breeds

A
  • Hypothermia
  • Catheter placement
  • Questionable accuracy of
    monitors
  • Accuracy of drug dosages
  • Hands-on assessment limited
    during anesthesia
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14
Q

Giant breeds

A
  • Lower drug dosages required
  • Considered geriatric at a
    younger age
  • Patient handling more difficult
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15
Q

Herding breeds

A

Mutations in the MDR-1 gene (prolonged effect of some drugs)

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16
Q

Boxers

A

Drug sensitivity (acepromazine)

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17
Q

Greyhounds (+ other sighthounds)

A

Drug sensitivity, prolonged
recovery from some drugs (propofol, barbiturates)

Other similarly lean-muscled breeds may also appear more sensitive to lipophilic drugs (most anesthetic drugs)

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18
Q

Miniature schnauzers

A

Sick sinus syndrome

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19
Q

Dobermans

A

Abnormal concetrations of von Willebrand factor (73%)
- Buccal mucosal bleeding time may
be measured

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20
Q

Anamnesis, age

A

Pediatric and geriatric patients at a higher risk – smaller drug dosages
required

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21
Q

What to take in consideration in case of pediatric patients?

A
  • Immature organs and defence mechanisms
  • Prone to hypothermia, hypoglycemia, regurgitation
  • Blood loss more dangerous
22
Q

What to take in consideration in case of geriatric patients?

A
  • Reduced response to hypercapnia, hypoxemia
  • Slower metabolism and healing, decreased organ function
  • Prone to hypothermia, regurgitation
23
Q

Principles of preoperative care

A

Clinical examination

Diagnostic tests

Stabilization:
- Optimizing hemodynamics if possible
- Optimizing respiratory function (also preoxygenation)
- Optimizing hydration status (fluid therapy)
- Preoperative fasting
- Analgesia and sedation
- Thermoregulation
- Positioning

24
Q

Why is clinical examination important?

A

Benefits of evaluating patients before general anesthesia are often underestimated

Evaluation of risks and the necessity of further diagnostic tests

Full clinical examination always warranted, but sometimes not
possible

25
Q

Clinical examination cardiovascular system

A

Heart auscultation

Pulse (peripheral)

Mucous membranes

26
Q

Clinical examination of respiratory system

A

Breathing pattern and noises

Lung auscultation

Mucous membranes

Palpation of trachea

27
Q

Clinical examination of hydration status

A

Mucous membranes

Skin turgor

Eyes

28
Q

Clinical examination of GI and urinary system

A

Abdominal palpation

29
Q

Clinical examination of integumentary system

A

Appearance of skin

Signs of inflammation/infection?

30
Q

Clinical examination of CNS

A

Assessment of mentation

Neurological examination

31
Q

2 basic things we check during clinical examination

A

BCS and temperature

32
Q

Which preoperative diagnostic test are recommended?

A

Choise of tests depends on the patient (clin. exam) and the owner.

PCV, total protein, glucose, urea at least

Hematology, biochem, urianalysis

Xrays, us, mri, ct

Further tests e.g. ECG, blood typing

33
Q

Patient stabilization

A

All patients should be stabilized prior to sedation if possible
* Hemodynamics
* Respiratory function
* Hydration status

Some emergency patients in critical
condition need immediate surgery,
but most benefit from preoperative
stabilization

34
Q

Preoperative fasting

A
  • Reduced amount of contents in the stomach → reduced possibility of
    vomiting, gastrointestinal reflux and consequently aspiration
  • Care should be taken when dealing with (risk of dehydration,
    hypoglycemia):
  • Pediatric patients
  • Cachectic patients
  • Concurrent diseases (fever, diabetes, etc. [polyuria])
  • Different species
  • Fasting of 2-4 hours for water and 6-8 hours for food should be
    enough in most cases
35
Q

Sedation and analgesia; choice of drugs depends on…

A
  • Patient characteristics (age, breed, concurrentdiseases, etc.)
  • Expected severity of pain
  • Surgical procedure
36
Q

Sedation and analgesia

A
  • Optimal pain control during and after anesthesia is of critical
    importance (not all anesthetics provide analgesia!)
  • Multimodal anesthesia and analgesia are preferred
  • Both NSAIDs and opioids often used unless contraindicated
  • A familiar anesthetic protocol is often the best anesthetic protocol
37
Q

Why pre-oxygenation (100%) is warranted before sedation?

A

To prevent hypoventilation/hypoxemia

38
Q

When is oxygenation started and how long it lasts?

A
  • Started before induction and
    intubation
  • Usually lasts 3-5 minutes and stopped immediately before intubation
  • Administration of oxygen is continued after intubation
39
Q

What is the most common complication of anesthesia?

A

Hypothermia

Warming should be started as soon as possible

40
Q

What hypothermia may cause?

A

Hypoxia, prolonged recovery from
anesthesia, an increased infection risk, worse cardiovascular
parameters

41
Q

Ways of thermoregulation during surgery

A
  • Warm room temperature – most effective
  • Warm water – also effective
  • Electric heating bags/table – always warranted
  • Warm infusions – not very effective (increase by ~0,5 oC)
  • Infrared light – not recommended without a folium blanket (may
    promote inflammation)
42
Q

What is the purpose of intraoperative fluids?

A
  • Maintenance of hemodynamics
  • Maintenance of the catheter
  • Amortization of fluid and blood loss
43
Q

Intraoperative fluid guidelines

A

American Animal Hospital Association guidelines:
* Starting dose of 5 ml/kg/h for dogs and 3 ml/kg/h for cats
* Can be reduced 25% each hour (unless fluid/blood loss)

Most often used – Ri-Lac or Hartmann’s solution (not NaCl 0,9%)

In case of hypotension
* Crystalloid bolus 10-30 ml/kg for 10-15 min (depending on mean arterial pressure)
* Colloid bolus 2-10 ml/kg for 5-10 mins (depending on mean arterial pressure)

44
Q

What to take into consideration when positioning the patient

A
  • Intubation, catheterization
  • Procedure, monitoring
  • Well-being of the patient
45
Q

Immediate postoperative concerns

A
  • Pain
  • Anxiety
  • Cardiorespiratory function
    • Blood pressure
    • Oxygen saturation
  • Temperature
  • Procedure-related factors
  • Wound protection
  • Postoperative period should be made as pleasant as possible
46
Q

Postoperative care, patient has to be closely monitored until it:

A
  • Has been extubated
  • Is laying on sternum, head elevated
  • Is able to swallow, has normal ocular reflex
  • Has a strong and regular peripheral pulse
  • Has an oxygen saturation of >94%
  • Has no suspicion of upper airway obstruction
  • Has effective analgesia
  • Has no evident bleeding

Highest death rate 3 hours after extubation

47
Q

Postoperative care

A
  • Pain management
  • Nutritional management
  • Wound care (protection, antibacterials)
  • Care related to surgical procedure
  • Exercise restriction
  • Immobilization
  • Other care possibilities
  • Home care – instructions necessary!
48
Q

Postoperative pain management

A

Better options for analgesia in the
clinic – should be left as an inpatient
until pain under control

Options for analgesia at home:
* NSAIDs
* Tramadol
* Fentanyl/lidocaine patch
* Ca++ channel blockers (e.g. gabapentin)
* Etc.

Length of treatment is determined by the procedure and the patient

49
Q

Procedure-related care

A
  • Postoperative care depends on the surgical procedure and the
    condition of the patient
  • Catheterization
  • Feeding tubes
  • Limb immobilization
  • Laser therapy
  • Physiotherapy
  • Etc.
50
Q

Wound care

A
  • Owner must be instructed in detail
  • Wound care should be provided daily (usually up to 14 days)
  • Wound exudate should be removed
  • Cleaning with physiological solution is recommended
  • Wound gels may be applied
  • Suture material usually removed after 7-14 days
  • A follow-up is also warranted in case an intradermal pattern was used