Cardiopulmonary effects of dobutamine and norepinephrine infusion in healthy anesthetized alpacas

Caitlin J. Vincent Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

Search for other papers by Caitlin J. Vincent in
Current site
Google Scholar
PubMed
Close
 DVM
,
Alexander T. Hawley Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

Search for other papers by Alexander T. Hawley in
Current site
Google Scholar
PubMed
Close
 DVM, MS
,
Elizabeth A. Rozanski Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

Search for other papers by Elizabeth A. Rozanski in
Current site
Google Scholar
PubMed
Close
 DVM
,
Kara M. Lascola Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

Search for other papers by Kara M. Lascola in
Current site
Google Scholar
PubMed
Close
 DVM, MSc
, and
Daniela Bedenice Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

Search for other papers by Daniela Bedenice in
Current site
Google Scholar
PubMed
Close
 Dr med vet

Abstract

Objective—To characterize the cardiopulmonary effects of dobutamine and norepinephrine infusion in isoflurane-anesthetized healthy alpacas.

Animals—8 adult alpacas.

Procedures—Initial baseline cardiovascular, respiratory, and metabolic variables were obtained 30 minutes after induction of isoflurane anesthesia in 8 alpacas (3 females and 5 sexually intact males). Four treatments (dobutamine at 4 and 8 μg/kg/min and norepinephrine at 0.3 and 1 μg/kg/min) were administered in random order via constant rate infusion over 15 minutes, followed by repeat measurements of cardiopulmonary values and a 20-minute washout period. Subsequent baseline and posttreatment measurements were similarly repeated until both drugs and dosages were administered to each animal. Baseline data in awake alpacas were obtained 18 to 24 hours following recovery from anesthesia.

Results—Both dobutamine and norepinephrine significantly increased cardiac index and arterial blood pressure from baseline values. Similar increases in hemoglobin concentration, oxygen content, and oxygen delivery were observed following administration of each drug at either dosage. Only dobutamine, however, reduced relative oxygen consumption while improving overall tissue oxygenation. Furthermore, heart rate was selectively enhanced by dobutamine and systemic vascular resistance by norepinephrine. Norepinephrine infusion resulted in dose-dependent changes in cardiopulmonary variables.

Conclusions and Clinical Relevance—Results indicated that both dobutamine and norepinephrine were appropriate choices to improve cardiac index, mean arterial pressure, and overall oxygen delivery in alpacas with isoflurane-induced hypotension. Careful titration by use of low infusion rates of dobutamine and norepinephrine is recommended to avoid potential arrhythmogenic effects and excessive vasoconstriction, respectively.

Abstract

Objective—To characterize the cardiopulmonary effects of dobutamine and norepinephrine infusion in isoflurane-anesthetized healthy alpacas.

Animals—8 adult alpacas.

Procedures—Initial baseline cardiovascular, respiratory, and metabolic variables were obtained 30 minutes after induction of isoflurane anesthesia in 8 alpacas (3 females and 5 sexually intact males). Four treatments (dobutamine at 4 and 8 μg/kg/min and norepinephrine at 0.3 and 1 μg/kg/min) were administered in random order via constant rate infusion over 15 minutes, followed by repeat measurements of cardiopulmonary values and a 20-minute washout period. Subsequent baseline and posttreatment measurements were similarly repeated until both drugs and dosages were administered to each animal. Baseline data in awake alpacas were obtained 18 to 24 hours following recovery from anesthesia.

Results—Both dobutamine and norepinephrine significantly increased cardiac index and arterial blood pressure from baseline values. Similar increases in hemoglobin concentration, oxygen content, and oxygen delivery were observed following administration of each drug at either dosage. Only dobutamine, however, reduced relative oxygen consumption while improving overall tissue oxygenation. Furthermore, heart rate was selectively enhanced by dobutamine and systemic vascular resistance by norepinephrine. Norepinephrine infusion resulted in dose-dependent changes in cardiopulmonary variables.

Conclusions and Clinical Relevance—Results indicated that both dobutamine and norepinephrine were appropriate choices to improve cardiac index, mean arterial pressure, and overall oxygen delivery in alpacas with isoflurane-induced hypotension. Careful titration by use of low infusion rates of dobutamine and norepinephrine is recommended to avoid potential arrhythmogenic effects and excessive vasoconstriction, respectively.

All Time Past Year Past 30 Days
Abstract Views 59 0 0
Full Text Views 586 338 61
PDF Downloads 243 111 6
Advertisement