delivered from a prolonged dystocia (\13120 minutes)
with an APGAR score of 6 received a wide variety of
fluid approaches ranging from none (with further
close observation) to 500 mL t o1Lof
isotonic poly-
ionic crystalloid fluids. In this situation— unless
blood loss occurred or there was severe in utero
sepsis—vascular volume resuscitation is not neces-
sarily required initially. The APGAR score sug-
gests a mildly to moderately asphyxiated foal, and
additives suggested by respondents were aimed at
early intervention for this. Supplements suggested
to be added to the first bag included (in order of
frequency mentioned): dextrose (1% to 5%), thia-
mine (1 g/L), vitamin C, DMSO (1% to 2%), and 50%
MgSO
4(25 mL). Dextrose is aimed at providing
energy support, thiamine supports normal intracel-
lular energy metabolism, vitamin C and DMSO are
provided as anti-oxidant treatment, and magnesium
is thought to be neuroprotective. The second foal case, an obtunded, hypothermic
minimally responsive 24-hour-old foal, represents a
variety of conditions of the critically ill neonate
ranging from severe sepsis to hypoxic ischemic dis-
ease. Initial treatment of these foals is fairly uni-
form and aimed at stabilization and intravascular
volume resuscitation in addition to providing an en-
ergy source. All respondents chose to administer
isotonic polyionic crystalloid replacement fluids at
bolus rates (20 mL/kg over 20 minutes, repeated as
necessary), but the majority also recognized the
need for almost immediate energy support. Energy
support was supplied either as a piggyback CRI
(4 mg/kg per minute, \13
250 mL/h 5% dextrose solu-
tion to a 50-kg foal) or as a 1% additive to the first
crystalloid bag followed by a CRI as described.
I personally tend to include the first dose of any IV
antimicrobial treatment in the first bag in addition
to 1% dextrose while I begin preparing for dextrose
CRI (5% dextrose at 250 mL/h initially will work for
most foals) in these cases.
CNS Trauma
The 2-year-old Thoroughbred filly with a head injury
from falling backward on its poll, with no epistaxis,
represented a case of CNS trauma. This type of
injury is not uncommon in practice and is probably
seen most commonly in foals being halter-broken.
The concern in these cases is the severity of injury,
if there is basisphenoid injury, and if there is rectus
capitis rupture or avulsion from the skull base.
In this example, it was suggested that rectus capitis
avulsion did not occur as a result of the absence of
epistaxis. Coup– contra coup injuries also occur
with these injuries, and fluid therapy is aimed at
minimizing edema and further injury to the brain.
Hypertonic saline is commonly recommended in the
treatment of CNS injuries,
8,9 particularly those in -
volving the brain, and the respondents were appar-
ently aware of this as hypertonic saline was the fluid
of choice for the majority. A few chose not to ad-
minister fluids immediately, whereas others opted for isotonic polyionic crystalloids or 0.9% saline.
Additives included thiamine. MgSO
4 was also
added to follow-up fluids at 20 mL 50% MgSO
4/L for
a maximum of 50 mg/kg.
Renal Injury
The anuric 10-year-old Arabian mare, badly tied up
after an apparently energetic trail ride, represented
a case of acute kidney injury associated with pig-
ment (myoglobin) released from the body and depos-
ited in the renal tubules. Initiation of diuresis is the
first-order treatment in these cases. Respondents
chose to treat this mare with isotonic polyionic crys-
talloid replacement fluids as a bolus (generally 20 L),
0.9% saline, or hypertonic saline followed by isotonic
polyionic crystalloid replacement fluids. Caution is
required because continued administration of fluids
to cases such as this without inducing urine produc-
tion can be harmful and result in fluid overload with
pulmonary edema. If an initial bolus does not re-
sult in urine production, other methods of inducing
diuresis should be attempted, such as furosemide,
and fluid administration must be slowed down or
stopped.
5. Conclusions
Hypertonic saline (1-L bags), isotonic polyionic crys-
talloid fluids with a normal strong ion difference (1 L
and 3- to 5-L bags) and 5% dextrose in water (1-L
bags) appear to be the most commonly chosen IV
fluids in this survey. Volumes that might be useful
to have on hand for an initial IV fluid resuscitation
in an ambulatory situation might include the
following: Foals: 1 t o 4 L isotonic polyionic crystalloid; 2 L
5% dextrose Adults: 2 L 7.5% hypertonic saline; 20 to 30 L
isotonic polyionic crystalloid; hetastarch Commonly mentioned additives included thiamine,
calcium (23% calcium gluconate), magnesium (50%
MgSO
4), and polymyxin B, and all are easily carried
in an ambulatory practice. If practical and within
the client’s budget, hetastarch or a similar colloid
may prove useful in some situations. The reader is cautioned that additional fluids
would be required for continued treatment of all
cases listed above. Some specific fluid brands are
listed in Table 1.
References and Footnotes
1. Lakritz J, Madigan J, Carlson GP. Hypovolemic hyponatre-
mia and signs of neurologic disease associated with diarrhea in
a foal. J Am Vet Med Assoc 1992;200:1114 –1116.
2. Magdesian KG, Hirsh DC, Jang SS, et al. Characterization of Clostridium difficile isolates from foals with diarrhea: 28
cases (1993–1997). J Am Vet Med Assoc 2002;220:67–73.
3. Magdesian KG. Neonatal foal diarrhea. Vet Clin North Am
Equine Pract 2005;21:295–312.
4. Hollis AR, Wilkins PA, Palmer JE, et al. Bacteremia in equine neonatal diarrhea: a retrospective study (1990 –
2007). J Vet Intern Med 2008;22:1203–1209.
5. Pfennig CL, Slovis CM. Sodium disorders in the emergency
456 2013 fiVol. 59fiAAEP PROCEEDINGS
HOW-TO SESSION: FIELD ANESTHESIA AND PAIN MANAGEMENT