General Anesthesia pt.2

Question 1

How is inhalation anaesthesia administered?

Answer 1

• Gaseous anaesthetics require suitable equipment for storage and administration
• Volatile liquid anesthetics are administered using calibrated vaporisers, using air, oxygen, or nitrous oxide-oxygen mixtures as the carrier gas

Question 2

What is done to prevent hypoxia when using inhalation anaesthesia?

Answer 2

-To prevent hypoxia, the inspired gas mixture should contain a minimum of 25% oxygen at all times
- Higher concentrations of oxygen (greater than 30%) are usually required during inhalation anaesthesia when nitrous oxide is being administered

Question 3

What drugs can be used as inhalation anesthetics?

Answer 3

• Desflurane
• Isoflurane
• Nitrous oxide
• Sevoflurane
• Halothane (discontinued in many countries)

Question 4

Volatile anaesthetics is the most common cause of which condition?

Answer 4

• A rare but potentially lethal complication of anaesthesia known as malignant hyperthermia is most commonly caused by volatile anaesthetics
• Should be avoided in patients at high risk of malignant hyperthermia

Question 5

What is malignant hyperthermia characterized by?

Answer 5

Characterized by a rapid rise in temperature, increased muscle rigidity, tachycardia, and acidosis

Question 6

Aside from volatile anesthetics, what has also been implicated in the development of malignant hyperthermia?

Answer 6

Suxamethonium chloride

Question 7

What is used in the treatment of malignant hyperthermia?

Answer 7

Dantrolene sodium

Question 8

What is nitrous oxide used for in the field of anaesthesia?

Answer 8

• For maintenance of anaesthesia, and in sub-anaesthetic concentrations, for analgesia
• Its use increases anesthetic depth, resulting in decreased dose requirements for coadministered anesthetic agents
• Can’t be used as a sole anaesthetic owing to lack of potency, but is useful as part of a combination of drugs since it allows a significant reduction in dosage

Question 9

Why has halothane been taken off the market in several countries?

Answer 9

Concern about hepatotoxicity has eliminated the use of halothane in North America; however it is still commonly used in some regions, particularly in pediatric patients