Respiratory and metabolic effects of massive administration of isotonic saline solution in heaves-affected and control horses.
BACKGROUND
It has been suggested that rapid administration of isotonic saline solution relieves airway obstruction in heaves-affected horses, but the efficacy and tolerability of this treatment is poorly documented.


OBJECTIVE
To determine the respiratory and metabolic effects of a rapid administration of isotonic saline solution in control horses and those with heaves.


METHODS
Thirty litres isotonic saline solution were administered i.v. to 5 control (Group C) and 9 heaves-affected horses (Group H). Pulmonary function testing and arterial blood gas analysis were performed prior to saline infusion, at 90 and 180 mins after starting the infusion, and 1, 3, 6 and 10 days later. PCV, plasma total solids, plasma electrolytes (Na+, Cl- and K+) and venous blood gas analysis were performed prior, during and after saline infusion.


RESULTS
Rapid saline administration was shown to have no beneficial effects on lung function during infusion in Group H. On the contrary, they had significantly increased pulmonary resistance (RL) at 180 mins following the initiation of saline administration compared to baseline. In Group C, saline administration resulted in a significant increase in RL at 180 mins and a significant decrease in PaO2 at 90 mins. These results suggest a transient decrement in lung function caused by rapid saline administration. Group H had a metabolic alkalosis with hypochloraemia at baseline compared to control horses. This resolved following i.v. saline administration and returned to baseline within 6 h after treatment had been discontinued.


CONCLUSIONS
The administration of saline to Group H did not improve airway function significantly, but resulted in mild and transient side effects.


CONCLUSIONS
Rapid administration of isotonic saline alone is not an effective therapy for heaves in horses.
Jean
D
D
Département de Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, CP 5000, St-Hyacinthe, Québec J2S 7C6, Canada.
Vrins
A
A
Lavoie
J P
JP
D000136:Acid-Base Equilibrium; D000402:Airway Obstruction / Q000628:therapy / Q000662:veterinary*; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D016022:Case-Control Studies; D005260:Female; D006734:Horse Diseases / Q000628:therapy*; D006736:Horses; D007262:Infusions, Intravenous / Q000662:veterinary; D007552:Isotonic Solutions / Q000008:administration & dosage / Q000627:therapeutic use; D007700:Kinetics; D010101:Oxygen Consumption; D012129:Respiratory Function Tests / Q000662:veterinary; D012965:Sodium Chloride / Q000008:administration & dosage* / Q000627:therapeutic use
D007552:Isotonic Solutions; D012965:Sodium Chloride