Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
monitor. A primary blood gas and chemistry was run
on the Nova® (Nova Stat Profile Critical Care Xpress
(CCX), Nova biomedical Corp., Waltham, MA) blood
gas analyzer for basic chemistry and blood gas
analysis. Each sample was spun at an apex of
approximately 6,000 rpm (2,000 x g). Serum was used
to run a full chemistry panel using the Alpha
Washerman® (Alfa Wassermann ACE; Clinical
System, West Caldwell, NJ, USA) blood chemistry
analyzer. These tests were used to establish the overall
internal physiological health of each canine patient.
Only patients found to be within normal ranges met the
criterion for this study. The weight, sex, and breed of
each canine patient was also recorded.
Each experimental subject received a
peripheral intravenous catheter in the left or right
cephalic vein and subsequently placed on Normasol-
R® (Normasol-R; hospera inc., Abbott Laboratories,
Chicago, IL) crystalloid fluid therapy for 1-2 hours preanesthetically
at 2.5 mL/kg/hr.
Patients were anesthetized using a preanesthetic
pain medication, Hydromorphone HCl (2.0-
mg/mL) injectable, administered intravenously (IV),
and dosed by weight at 0.1 mg/kg. Anesthesia was
induced using the IV injectable anesthetic, Propfol
(Proflo®, Abbott Laboratories, North Chicago, IL), at a
dose of 5 mg/kg titrated to effect. Each test subject was
then intubated with a sterile cuffed endotraecheal tube.
Anesthetic was maintained using a gas anesthetic
agent, Isoflurane (IsoFlo®; Abbott Laboratories, North
Chicago, IL USA), which was delivered by a closed
circuit system via a constant flow of oxygen at 2.0
L/min passed through an Isoflurane vaporizer (Drager,
Lubeck, Germany) initially at the rate of 3.0 % ± 1.5 %
(dependent on weight and initial anesthetic depth).
Crystalloid fluid therapy was increased 5 ml/kg/hr
while under anesthesia to ensure proper profusion
during the procedure.
A 25 gauge tuberculin syringe was used to
draw 0.10 mL of blood from the saphenous accessory
vein of the hind limb and added to the lactate testing
strip for lactate analysis. Samples were taken at 20
minute intervals for the remainder of the procedure
including one immediate post-induction sample and
then processed immediately with the Accutrend®
handheld Lactate monitor. Each study patient was
monitored using the LifeWindow 6000V vital signs
monitor (multi-parameter patient monitor, LW6000;
Digicare Biomedical Technology, West Palm Beach,
FL), in addition to visual supervision by the veterinary
surgical nurse and veterinarian. Heart rate (Beats Per
Minute), blood pressure (mmHg), respiratory rate
(Breaths Per Minute), ETCO 2 (%), SPO 2 (%),
temperature (ºF), IV fluid rate (mL/hr), anesthetic level
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Saddleback Journal of Biology
Spring 2008
(%), O 2 level, and blood lactate levels were measured
and recorded at specific time intervals throughout the
procedure. Each patient received heat support via a
warm air delivery system and a heated surgical table
(Bair Hugger®; Arizant Healthcare Inc., Eden Prairie,
MN), during the anesthetic procedure.
Results
The ten canine patients involved in this study
showed a significant increase in average blood lactate
levels as the time under anesthesia elapsed. A Singlefactor
ANOVA (Analysis Of Variance) test was run to
determine the average means and P-value of the blood
lactate levels. To see where the difference was, a
Bonferroni Correction test was run between all groups
against the 0 minute time interval. To be considered
statistically significant the P-value must be ≤0.008. The
ANOVA results showed P=9x10 -16 indicating a
statistically significant P-value.
The initial mean blood lactate level (0 min)
was 1.435mmol/L and was used as a baseline
parameter to compare the increasing blood lactate level
samples. In comparing the 0 min mean lactate level
with the 20 min mean lactate level (1.89mmol/L), there
was no statistical difference. However, when compared
with the 40 min mean sampling (2.2mmol/L), there
was a 53% increase in blood lactate level. When
compared with the 60 min mean sampling
(2.56mmol/L), there was a 78% increase. When
compared to the 80 min mean sample (2.82mmol/L),
there was a 96% increase. Finally, when compared
with the 100 min mean sampling (3.03mmol/L), there
was a 111% increase in blood lactate level (Figure 1).
Figure 1. Graph displaying the percent increase of
blood lactate levels over given time intervals with P=
9x10 -16 . Blood lactate levels steadily increased as time
under anesthesia elapsed.
Discussion