92
46TH
ANNUAL
CONGRESS
OF
THE
SAEVA
SKUKUZA
16-‐20
FEBRUARY
2014
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the abdominal cavity. If the urine production is greater than 2 mL/kg/hr than
the intravascular compartment is generally adequately restored. The fluid rate
may be dropped after considering MAP and heart rate parameters.
Correcting acid/base disturbances should be considered only when adequate
perfusion has been restored. Often the academia will begin to resolve once
appropriate intravascular volume has been achieved.
These general guidelines are adequate for most patients requiring emergency
intervention. Remember to always count and keep track of a) the volume of fluids
given; b) over what time period; and c) what the response was to the fluid. This will
aid in adapting the initial fluid plan to manage the patient. The reader is encouraged
to read more elaborate fluid resuscitation information for a more complete
understanding of fluid management (Cook et al. 2003, Snyder et al. 2013). An
important “anecdotal” tip is that synthetic colloid administration volume should not
exceed 10 to 20 mL/kg/day. This will help avoid potential coagulopathies (Cook et al.
2003)
Pharmacological interventions tips
If fluid resuscitation is not correcting a hypotensive state (often the case in colic
patients) despite improving or fully replacing the intravascular compartment, then
the clinician should explore pharmacological interventions to improve patient
perfusion (Schauvliege et al. 2013, Fantoni et al. 2013, Dugdale et al. 2007). Colic
patients under general anaesthesia virtually always require either an inotrope and/or
a vasopressor for haemodynamic support, despite there being evidence to suggest
that there is no improved outcome or increase in survival (Schauvliege et al. 2013,
Dugdale et al. 2007).
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Dobutamine: β1 agonist at recommended dose rate (1 to 5 µg/kg/min). Acts
as a positive inotrope. Best used when intravascular compartment has enough
circulating volume. Diastolic pressures should ideally be above 45 mmHg to
improve coronary circulation during diastole. Excessive dose rates may cause
sinus tachycardia without any beneficial increase in blood pressure. Most
practical method of application: for a 500kg horse; mix ½ vial (10 mL) of
dobutamine 250mg/20 mL into a 200 mL lactated Ringers or normal saline.
Administer using a 60-drop admin set. Set drip rate to 1 drop per second and
monitor response. If you wish to keep the compounded solution for longer
than 12 hours then you should consider mixing a 5% dextrose solution to
200 mL bag improve the stability.
Phenylephrine: α1 agonist and useful vasopressor. Works well in selected
cases, such as horses experiencing pronounced vasodilation (endotoxemia,
hypercapnia). Best use is in cases where clinicians suspect pronounced
vasodilation and wish to improve or normalise vascular tone. Easiest method
of application is to spike 3 L isotonic crystalloid bag with 10 mg of
phenylephrine (1 vial) and run bag at full open using a 20-drop administration
set. Phenylephrine does not improve the cardiac index and only improves
MAP by causing intense vasoconstriction. This means that the blood pressure
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