TIVA versus PIVA Total IV anesthesia (TIVA) is a way of providing sedation and general anesthesia in an office-based setting without the use of volatile anesthetic agents such as sevoflurane and desflurane. TIVA used in monitored anesthesia care is most effective when used in conjunction with a nerve block or dense field block. (Hausman et al., 2022) TIVA is commonly used for anesthesia where there are no facilities for inhalational anesthesia such as in some rural spay/ neuter programs. Total intravenous anaesthesia (TIVA) has a number of potential benefits over intravenous induction followed by inhalational maintenance of anaesthesia. These include improved recovery quality and haemodynamic stability, the avoidance of occupational exposure to inhalational anaesthetics, and reduced environmental impact (Langton, 2023). Agents used for TIVA: ● Propofol Anesthetic gas toxicity Exposure to waste anesthetics in veterinary practices are common; unfortunately, it is far less reported compared with human hospitals. High concentrations of waste anesthetic gases (e.g., nitrous oxide, isoflurane, desflurane, and sevoflurane) can increase health risks for the veterinarians who are exposed. Today, levels of occupational exposure to anesthetic gases are typically controlled or mitigated using scavenging systems, effective general ventilation systems, and systems to detect and reduce gas leaks. However, low concentrations of volatile anesthetic gases can still find their way into the ambient air of both the clinical and veterinary surgical theatres through leaks in the components of the anesthesia delivery system. (Pokhrel et al., 2021) Potential sources of waste anesthetic gases (WAGs): ● High- and-low pressure machine connections ● Spillage of liquid anesthetics during the filling of vaporizers ● Improper handling of gases ● Accidental spillage of anesthetics during filling operations ● Breathing circuit during anesthesia induction ● Exhaled by the patient during recovery Health effects of occupational exposure to WAGs (Canadia Centre for Occupational Health and Safety, 2024): ● Alfaxalone ● Ketamine ● Endotracheal tube ● Anesthetic machine ● Tank valves
The partial intravenous anesthesia technique (PIVA) is the use of an infusion anesthetic that reduces the concentration of anesthetic gases needed to maintain anesthesia. The depth of anesthesia can be controlled during surgery by changing the infusion rate of intravenous drugs without increasing the amount of anesthetic gases, which makes the use of inhalation anesthetics even smaller (Kucharski, 2022). Drugs commonly used for PIVA: ● Opioids Advantages of PIVA (Kucharski, 2022): 1. Good, stable quality of anesthesia 2. Great control over the doses of administered drugs 3. A better post-anesthetic time 4. Reduced cardiopulmonary depression because less inhalant agents can be used Ways to decrease exposure to anesthetic gas (Environmental Health and Safety, 2024): ● Anesthetic gases must always be used in a well- ventilated room with no recirculation of locally exhausted air. ● Anesthetic gases must always be used with a scavenging/ventilation mechanism that eliminates inhalation exposure to the staff. ● In veterinary operating rooms, it is recommended to have ventilation of at least 15 air changes per hour, with at least three air changes of fresh air per hour. ● Alpha-2 adrenergic agonists ● Injectable anesthetic agents ● Lidocaine ● Use local exhaust ventilation whenever possible for operations that involve handling and use of liquid and gaseous anesthetic agents and the control and exhaust or disposal of waste anesthetic gases (WAGS). ● Conduct procedures using a chemical fume hood, hard-ducted biosafety cabinet, ducted downdraft table, snorkel trunk, or other local exhaust device especially for small scale procedures. ● The local exhaust capture hood (e.g., snorkel hood) should be positioned between the isoflurane source and the individual using it (within 6 inches of the source as a general rule). ● Ensure animal’s nose fits snugly into the cone. The outer cone should extend one quarter inch beyond the inner cone to capture and exhaust waste anesthetic gas. ● The vaporizer unit should be filled and refilled in an area with local exhaust. ● All hinged induction boxes, desiccators, and other similar containers used as induction boxes should be used in a chemical fume hood or a biosafety cabinet connected to a fume exhaust system designed for chemical use to contain, capture, and remove anesthetic gases. ● Have a ventilation system that circulates and replenishes the air with at least six air changes per hour and a minimum of two air changes of fresh air per hour.
● Headache ● Irritability
● Fatigue ● Nausea ● Drowsiness ● Difficulties with judgment and coordination ● Liver and kidney disease ● Sterility ● Miscarriage and birth defects ● Cancer
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Book Code: VFL1526
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