Inhalational Flashcards
What are examples of inhalational anaesthetics?
Halothane Isolfularane Sevoflurane Deflurane Enflurane Metoxyflurane
What are exmaples of carriers for inhaltional anaesthetics?
Oxygen, nitrous oxide and carbon dioxide
When is oxygen used at 100%?
100% pure oxygen given to animals with: anaemia pulmonary pathology hypoventilation animals recovering from N2O anaesthesia/supplied during recovery if needed
What colour are the 2 types of carrier gas cyclinders?
Oxygen - black with white shoulders
Nitrious oxide - blue
What concentration is nitrous oxide given at?
2:1 N2O:O2 mixtures (double oxygen in non-rebreathing circuits and 1:1 in rebreathing circuits)
Given at 66% delivered
What is nitrous oxides second gas effect?
It enhances the uptake of halothane therefore allowing faster induction of anaesthesia
what care needs to be taken with nitrous oxide?
Do not use more than 80% N2Oas will lower oxygen levels below normal
N2O diffuses into gas-filled spaces and acculumates
Delivering N2O to a apteint with pathologica abdominal or thoracic distension should be avoided
Giving N2O to a patient with pneumothorax can cause it to double in size in 10mins
Do not use in bowel obstruction or middle ear disease
Describe diffusion hypoxia
Due to the fact that nitrous oxide has low solubility in blood, at the end of anaesthesia when N20 administration cease sthe N2O present in blood diffuses back into the alveoli and ‘dilutes’ the alveolar air so less oxygen is available.
Give advantages of inhalational anaesthesia
Depth of anaesthesia readily altered
Concentration of anaesthetic in blood or brain may be altered rapidly by changing vaporiser setting
Elimination of inhaled agents occurs mainly via the lungs therefore advantage is liver/kidney patient
Allows constant delivery of oxygen alongside patient
Most patients are intubated therefore IPPV may be performed and anaesthetic is safer
Give disadvantages of inhalational anaesthesia
Need for anaesthetic machine and range of equipment (cost)
Hazards, personnel health risk, explosion risk
Knowledge required of circuits and machine
Induction and recovery possibly delayed due to lung pathology
Describe the minimum alveolar concentration (MAC)
Measure of anaesthetic potency, defined as quantity of anaesthetic required to immobilize 50% of patients.
Agents with lower MAC valve are most potent
Describe the blood gas solubility
A measure of how readily the volatile agent dissolves into plasma
Give examples of inhalational agents
Halotahne Isofularne Sevoflurane Desflurane Eniflurane Methoxyflurane Ether
Give advantages of isoflurane
Good muscle relaxation
Analgesia
Fast recovery
Give Advantages of sevoflurane
Rapid induction Rapid recovery Pleasant odour Well tolerated for mask induction Non-irritant
