● Isoflurane. ● Sevoflurane.
mixed with the carrier gas (oxygen) in a controlled concentration set by the vaporizer dial. These are inhaled by the patient to keep the patient under general anesthesia.
Inhalational anesthetics are in liquid form and pass to their gaseous phase inside the vaporizer. In this vaporizer, they are Minimum Alveolar Concentration (MAC) The Minimum Alveolar Concentration is defined at the minimum concentration of an anesthetic agent measured at the level of the alveolus, which will prevent movement in response to a standard noxious stimulus such as a skin incision in 50% of the test study population. MAC is expressed as a percentage. In easier to understand terms is that MAC is a measurement of the potency of an anesthetic agent. The lower the MAC, the more potent the anesthetic agent: ● Isoflurane MAC : 1.3 to 1.6. ● Sevoflurane MAC : 2.3 to 2.5. ISOFLURANE ● Creates a pungent odor but not an irritant to the airways. Anesthetic gas toxicity Chronic toxicity is due to long term exposure to minimal amounts of anesthetic gases in the working environment. There are many things that can be done to decrease your exposure to these gases, such as: ● Using a scavenging system. ● Automatic air changes in the operating room. ● Ventilation of the working environment. ● Minimal use of mask and chamber induction. Summary In this chapter, we discussed the different options for maintaining general anesthesia. You should have a good understanding
● Mildly increases cerebral blood flow; is an acceptable choice in head trauma patients or patients with intracranial masses. ● Pronounced respiratory depression. ● Causes hypotension. SEVOFLURANE ● Does not have a pungent odor. ● Dose-dependent cardiovascular depression due to vasodilation. ● Less of a respiratory depressant than isoflurane. ● Some degradation of sevoflurane occurs when it is exposed to the soda lime. It produces a very small amount of a substance called Compound A . ● Check all machines and breathing systems for leaks before every use. ● Make sure that ET tube cuffs are inflated to seal the airway. ● Refill the vaporizer at the end of the day, so any spillage can have time to clear the area. ● Use a spill-proof vaporizer filling system that is found on newer vaporizers. ● Monitor anesthetic gas levels in the working environment..
of these drugs and how to keep yourself safe when around inhalational anesthetics.
PAIN MEDICATIONS
Learning objectives Discuss is the definition of pain. Explain the effect that the drug will cause the patient. Predict any side effects that you may see when using certain pain medication. Identify the pros and cons of some of the common classes of pain medications. Pain is an unpleasant sensory or emotional experience associated with actual or potential tissue damage. Pain can cause distress and suffering. Except to warn that something is wrong, pain never has beneficial effects and unmanaged pain can interfere with normal behavior. By activating the sympathetic nervous system, secondary pain will result in protein catabolism, abnormal renal function, electrolyte disturbances, immune suppression, and delayed healing. Pain can be very hard to quantify in many animals because of their stoic nature. Some common signs of pain in dogs are: ● Decreased interaction. Treating pain in dogs and cats Today, a multi-modal analgesia approach is used to treat pain. This refers to combining multiple analgesic drug classes or techniques to target different points along the pain pathway. This takes the advantages of additive or synergistic analgesic effects that optimize analgesia and improve patient comfort. It also lowers the dosage of individual analgesic agents that are required, which decreases the potential for the development of undesirable side effects. ● Anxious expression. ● Submissive behavior. ● Refusing to move.
● Whimpering. ● Howling. ● Growling. ● Guarded behavior. ● Aggression and biting.
● Loss of appetite. ● Self-mutilation. Common signs of pain in cats are: ● Decreased activity. ● Loss of appetite. ● Quite or loss of curiosity. ● Hiding. ● Hissing. ● Excessive licking and grooming.
● Stiff posture or gait. ● Guarded behavior. ● Attempts to escape. ● Not grooming. ● Tail flicking.
OPIOIDS Opioids are commonly used for the management of moderate to severe pain. For moderate to severe pain, usually pure mu- agonists such as morphine, methadone, or fentanyl is used. A very commonly used opioid in referral hospitals is fentanyl. This is used as a constant rate infusion and given as a CRI intraoperatively.
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Book Code: VFL1524
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