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Effect of frusemide and hypertonic saline on electrolytes during post exercise anaesthesia
Author(s) -
GREENE S.,
KEEGAN R.,
BROWN JENNIFER,
KINGSTON JANENE,
BAYLY W. M.
Publication year - 1999
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1999.tb05261.x
Subject(s) - anesthesia , hypertonic saline , medicine , saline , furosemide , tonicity
Summary This study evaluated the effects of pre‐exercise frusemide administration and hypertonic saline (H) infusion during anaesthesia on arterial pH, blood gases and electrolytes in 6 Thoroughbred horses anaesthetised immediately post exercise. Horses received either frusemide (F) (0.5 mg/kg, i.v.) or a saline placebo (P) injection 4 h prior to treadmill exercise. Exercise consisted of a 3 min warm‐up at 40% V̇O 2max followed by exercise to fatigue. Detomidine (40 μg/kg, i.v.) was given within 5 min of stopping and followed 5 min later by zolazepam‐tiletamine (1.25 mg/kg, i.v.) to induce anaesthesia. During maintenance of anaesthesia using isoflurane in O 2 . either isotonic saline solution (I) or 7.5% H (4 ml/kg, i.v.) was administered. Arterial blood was sampled at the following times: prior to (Pre‐F/P) and 4 h after (Pre‐ex) F or P administration, 1 min after fatigue (Fatigue), 5 min after induction of anaesthesia (Post‐ind), and just prior to and 15, 30 and 60 min after beginning isoflurane (ISFL) anaesthesia. Arterial pH and blood gas tensions, pulmonary arterial blood temperature, plasma [lactate], total protein and plasma [Na + ], [K + ], and [Cl − ] were measured. Data were analysed using 2‐way ANOVA for repeated measures (P<.05). There were significant differences over time for all variables except total protein. Plasma [Na + ] increased at Fatigue compared to Pre‐F/P or Pre‐ex in all treatment groups. Plasma [Na + ] and [Cl − ] increased during ISFL anaesthesia compared to Pre‐F/P and Pre‐ex in horses given H. During ISFL anaesthesia, plasma [Cl − ] decreased compared to Pre‐F/P in Group F+I horses. We conclude that acid‐base, blood gas, and electrolyte changes associated with F are unlikely to influence management of horses anaesthetised immediately following supramaximal exercise to fatigue. Hypertonic saline infusion may help restore plasma [Cl − ] faster in hypochloremic horses requiring anaesthesia immediately after strenuous exercise.