Acid-base status in dogs during long term anaesthesia

Area of Science:

• Veterinary Anesthesiology
• Cardiovascular Physiology
• Acid-Base Balance

Background:

• Anesthesia can alter physiological parameters in dogs.
• The direct effects of anesthesia on acid-base status require elucidation.
• Monitoring standard vital signs may not always detect early circulatory compromise.

Purpose of the Study:

• To investigate changes in acid-base status in dogs under anesthesia.
• To determine if anesthesia itself, without surgical intervention, affects acid-base balance.
• To assess the reliability of acid-base status as an early indicator of circulatory impairment during anesthesia.

Main Methods:

• Dogs were anesthetized using chloralose or chloralose-barbiturate combinations.
• Acid-base status was monitored over several hours.
• Arterial blood pressure and pulse rate were recorded.
• No surgical procedures were performed to isolate anesthetic effects.

Main Results:

• A progressive metabolic acidosis developed within 2-3 hours of anesthesia, irrespective of the agent used.
• This acidosis persisted for hours, even with stable blood pressure and pulse rate.
• Anesthesia induction impaired peripheral circulation.
• Rising body temperature may have contributed to acidosis.

Conclusions:

• Acid-base status is a more sensitive and earlier indicator of circulatory impairment during anesthesia than blood pressure or pulse rate.
• Anesthesia per se can lead to metabolic acidosis through circulatory compromise.
• Monitoring acid-base balance is crucial for detecting subclinical circulatory distress in anesthetized dogs.