Page 591 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

578 FLUID THERAPY

contractility and a parenterally administered positive maintained on lactated Ringer’s with 5% dextrose at
inotrope such as dobutamine is indicated. Despite diltia­ rate of 50 mL/hr. A full physical examination reveals
zem therapy this dog has a rapid ventricular rate and mild dehydration, abdominal pain, and a palpable
further medical treatment to address this problem maybe midabdominal mass. A dose of hydromorphone IV is
warranted. given. Ultrasound evaluation of the abdomen reveals free
abdominal fluid, a sample of which is aspirated, and
microscopic evaluation reveals a septic exudate.
CASE 3: Septic Shock
Intravenous, broad spectrum antimicrobials are given
A 5-year-old female spayed domestic short haired cat and reevaluation of the patient at this time shows no
weighing 4 kg is presented collapsed. She has a history change in the perfusion parameters, less abdominal pain,

of vomiting and inappetence for the last 48 hours. There and a temperature of 98.1 F. Doppler blood pressure at
is no known history of trauma or toxin exposure; the cat this time is 70 mm Hg. A central venous catheter is placed
has had no previous medical problems. in the jugular vein and the central venous pressure is
On presentation the cat is laterally recumbent and 2 mm Hg (2.72 cmH 2 O). Following 25 mL of 6%
unresponsive, mucous membranes are very pale, capillary hetastarch IV, the Doppler blood pressure is 75 mm
refill time cannot be determined, the heart rate is 140 Hg and the central venous pressure is 4 mm Hg
bpm, the femoral pulses are barely palpable, and the (5.44 cmH 2 O). Another 15 mL of 6% hetastarch is given

extremities feel cold. The rectal temperature is 93.6 F. and the blood pressure rechecked. The Doppler blood
On auscultation no murmur, gallop, or arrhythmia is pressure remains at 75 mm Hg and the central venous
evident; no abnormal breath sounds are heard. pressure is now 6 mm Hg (8.16 cmH 2 O). A second
Flow by oxygen is provided and several unsuccessful central venous sample is collected and reveals mild
attempts are made to place a peripheral venous catheter. improvement in the lactic acidosis and concurrent
An intraosseous catheter is placed in the proximal respiratory acidosis.
humerus and 100 mL of warm lactated Ringer’s solution
is given rapidly. Following this therapy, a cephalic venous
Second
catheter is placed and a jugular venous blood sample is
Sample Reference
obtained for analysis.
Parameter Values Range — Cat
Measured Reference pH 7.180 7.34-7.38*
PvCO 2 mm Hg 45.8 38-42*
Value Range—
PvO 2 mm Hg 38.1 49-67*
Parameter Presentation Cat
HCO 3 mEq/L 16.9 22-24*
SBE mEq/L 9.2 2to 8*
pH 7.045 7.34-7.38*
Glucose mg/dL 185 67-168
PvCO 2 mm Hg 50 38-42*
Lactate mmol/L 4.1 <2.5
PvO 2 mm Hg 34.7 49-67*
Packed cell volume % 26 25-45
HCO 3 mEq/L 12.8 22-24*
Total protein g/dL 5.0 6.0-8.6
SBE mEq/L 12.6 2to 8*
Glucose mg/dL 49 67-168
Lactate mmol/L 6.3 <2.5
A constant rate infusion of dopamine is started at a rate
Packed cell volume % 33 25-45
of 5 mg/kg/min and over the next 30 minutes it is
Total protein g/dL 6.5 6.0-8.6
titrated up to rate of 10 mg/kg/min at which time the
Doppler blood pressure is 100 mm Hg. The cat is now
Reevaluation of the patient at this time reveals pale sitting up and moving around, perfusion parameters have
mucous membranes, the capillary refill time still cannot improved with pale pink mucous membranes, capillary
be assessed, the heart rate is 160 bpm, and the femoral refill time is less than 2 seconds, heart rate is 180 bpm,
pulses have improved but are considered weak. The blood and there are fair femoral pulses. The cat is now consid­
work reveals a mixed acid-base disorder with both a lactic ered stable for induction of anesthesia and an exploratory
acidosis and a respiratory acidosis in addition to hypogly­ laparotomy.
cemia. One gram of dextrose IV is administered followed
by another 60 mL of warm lactated Ringer’s solution. Case 3 - Case Notes
A repeat blood glucose measurement is now 230 mg/dL. This cat was severely hypothermic and in circulatory
Following this therapy the cat is more responsive, the shock on presentation. Venous access in such cases can
heart rate is 190 bpm, and femoral pulse quality has be extremely challenging and intraosseous catheters can
improved but does not feel normal. Active warming is provide a rapid and reliable route of fluid and drug
started with a warm air blanket. Doppler blood pressure administration. The severe hypothermia is of concern
at this time reveals a pressure of 80 mm Hg. The cat is but active warming is delayed until fluid resuscitation