Contents of Today's Veterinary Practice - JAN-FEB 2012

Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.

Page 26 of 83

ANESTHETIC MONITORING: YOUR QUESTIONS ANSWERED |
Saved by Monitoring Case 1: Canine Abdominal Surgery
EVALUATION History: A 7-year-old, 25-kg mixed-breed dog presented with a 3-month history of chronic vomiting.
Physical Examination: The dog was bright and alert with strong femoral pulses; heart and lung sounds were within normal limits.
Blood Analysis: Packed cell volume, 44%; total protein, 5 g/dL; glucose, 125 mg/dL; some mild electrolyte imbalances were noted.
Imaging: Radiographic assessment, including a barium series, revealed dilation of the proximal small intestines.
Diagnosis & Treatment: Intestinal foreign body was suspected and exploratory abdominal surgery was scheduled. Pre-operative fluids were administered intravenously to correct the electrolyte imbalance.
ANESTHETIC MONITORING Anesthetic Protocol: UÊPremedication with acepromazine (0.02 mg/kg IM) and hydromorphone (0.01 mg/kg IM) UÊInduction with propofol (3 mg/kg IV) UÊMaintainance with isoflurane to effect
Blood Pressure Monitoring during Anesthesia: Oscillometric blood pressure monitoring was performed; blood pressure values were validated with simultaneous direct blood pressure measurement via pressure transducer and an arterial catheter placed in the dorsal pedal artery.
Monitor Warning: While the dog was undergoing pre-operative surgical prepping, its blood pressure began to decrease (20 minutes after induction).
Vital Signs of Anesthetized Patient (20 Minutes After Induction) Systolic blood pressure (mm Hg) Diastolic blood pressure (mm Hg) Mean blood pressure (mm Hg) Heart rate (beats/min)
81 32 49
Respiratory rate (breaths/min) Oxygen level in blood (SpO2) (%) End tidal CO2 (mm Hg)
Temperature (°F)
110 9
100 48
100.5 Diagnosis: Acepromazine/isoflurane-induced hypotension
Correction: Balanced electrolyte fluids (Plasma-Lyte A, baxter.com) were increased to 20 mL/kg/H and isoflurane reduced from 1.75% to 1.25%.
Pertinent Vital Signs After Fluid Administration & Isoflurane Reduction Systolic blood pressure (mm Hg) Diastolic blood pressure (mm Hg) Mean blood pressure (mm Hg)
108 50 70
DON'T MISS TOP 10 TIPS
ABOUT ANESTHESIA In the November/December 2011 issue of Today's Veterinary Practice, our Top Ten column featured the article Ten Tips to Improve Anesthesia in Your Practice (page 47). Dr. Lysa Posner provided information on medication combinations, local nerve blocks, decreasing induction drugs, and more. To read this article, go to our website, todaysveterinarypractice. com, and select Back Issues from the top navigation bar.
The new vital signs indicated improved blood pressure. Intra-operatively, the dog received two additional doses of hydromorphone (for its isoflurane-sparing effect and to provide additional analgesia) to maintain isoflurane between 1.25% and 1.75%.
Outcome: Foreign body material consistent with pieces of a stuffed animal was removed from the jejunum; a 4-inch section of the jejunum was resected and an anastomosis was performed. The dog recovered smoothly and uneventfully.
Take-Home Message: Without blood pressure monitoring to guide isoflurane adjustment, analgesia management, and fluid therapy, the dog's blood pressure would have remained low for an extensive period of time, resulting in poor tissue perfusion and potential morbidity and mortality.
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