Page 510 - WSAVA2017
P. 510

An Urban Experience
Respiratory Stabilisation
    Mild shock
   Moderate shock
   Heart rate
  ↑ Cats: ↑ or ↓
  ↑↑ Cats: ↑ or ↓
  ↓ Cats: ↓
   Pulse quality
  ↓ Vasodilatory: ↑
  ↓↓ Vasodilatory: ↑
  ↓↓↓ Vasodilatory: ↑ or ↓
   Mucous membrane colour
 Pale pink Vasodilatory: Injected
 Pale Vasodilatory: Injected
 Pale Vasodilatory: Injected
 Capillary refill time
  ↑ Vasodilatory: ↓
  ↑↑ Vasodilatory: ↓
  ↑↑↑ Vasodilatory: ↓ or ↑
 Extremity/ body temperature
  ↓ Vasodilatory: ↑
  ↓ Vasodilatory: ↑
  ↓ Vasodilatory: ↑
 There are many methods of oxygen delivery including flow-by, oxygen mask, oxygen hood, nasal prongs and oxygen cages. Care must be taken to minimise stress during oxygen administration. Flow-by oxygen provides the least concentration of oxygen (though potentially
up to FiO2 of 40%), but is well tolerated while being
able to examine and treat the patient at the same time. Mask oxygen provides greater concentration of oxygen compared to flow by, though may not be tolerated by some; in addition, contraindicated in hyperthermia and hypercapnia. Human nasal prongs are a useful hands free approach to oxygen administration to dogs who not significantly open mouth breathing. Oxygen chambers can be useful in stressed animals requiring larger concentration of oxygen (up to FiO2 of 60%), however contraindicated in hyperthermia and hypercapnic patients. Oxygen flowrates should be set at 50 – 100mL/ kg/min.
Sedation will decrease oxygen demand, help with respiratory stabilisation, and help facilitate procedures. Intramuscular sedation may be necessary if IV catheterization is too stressful.
Intubation and ventilation
Despite oxygen supplementation and sedation/analgesia, some patients may require immediate intubation and ventilation. It is important to be prepared by having an anesthetic machine with rebreathing bag or oxygen cylinder with ambubag; endotracheal tube with tie
and cuff syringe; IV catheter; induction agent; and monitoring equipment including ECG, pulse oximetry, and capnography.
Cardiovascular Assessment:
Assessment of heart rate and rhythm should be performed while concurrently palpating the pulses for pulse quality and deficits. If there are any abnormalities, ECG is recommended to diagnose any urgent cardiac disease as well as to monitor the patient easily while you are attending to other body systems.
Being able to assess for cardiovascular shock rapidly is also important. There are 4 types of shock:
· Hypovolemic (hemorrhage, dehydration, 3rd space loss of fluid)
· Cardiogenic (heart failure, arrhythmia)
· Obstructive (GDV, pericardial effusion, pneumothorax)
· Vasodilatory (systemic inflammatory response syndrome, sepsis, anaphylaxis)
Rapid clinical assessment involves the following parameters:
It is important to remember:
· If a dog is bradycardic and in decompensated shock, immediate treatment is necessary as further decompensation can lead to cardiac arrest;
· Cardiogenic shock should be identified, as it’s the only group not treated by fluids;
Cardiovascular Stabilisation:
Other than in cardiogenic shock and pericardial effusion a fluid bolus should be administered rapidly over 15 minutes at the following doses and the above parameters to be reassessed for improvement. Fluid boluses can be given up to 4 times except for hypertonic saline:
· Isotonic crystalloids (e.g. Lactated Ringer’s): Dogs: 10 – 20 mL/kg; Cats: 5 – 10 mL/kg
· Artificial colloids (e.g. Volulyte): Dogs: 5 mL/kg; Cats 2.5 – 5 mL/kg (Contraindicated in patients with kidney injury, coagulopathy or pulmonary disease)
· Hypertonic saline (e.g. 7% NaCl): Dogs and cats: 2 – 4 mL/kg (Contraindicated if severely dehydrated, sodium abnormalities; must give with isotonic crystalloids)
Large breed dogs may require a pressure bag to administer a bolus within 15 minutes. Care should be taken when administrating a bolus to cats, as incorrect use of fluid pumps can lead to fluid over load. As a safety measure, the author uses a 50 mL syringe and administers the fluids manually. Other options are the use of a syringe driver, or a paediatric burette attached to a fluid pump. Care should be taken in administering large volumes of fluid in patients prone to heart failure, pulmonary disease, anuric or oliguric renal failure, geriatric cats, hypoalbuminemia and sepsis or systemic inflammatory response syndrome.
Bradycardia and tachycardia
Treatment of individual causes of bradycardia/tachycardia is beyond the scope of this lecture; however, it is important to identify bradycardia and place and ECG. Critical bradycardia requiring specific urgent treatment includes decompensated shock, hyperkalemia, bradyarrhythmias, and intracranial hypertension. Tachycardia requiring urgent treatment includes pain, hypoxemia, anemia, and tachyarrhythmias.

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