With which inhalational agent is cardiac output moderately increased?

With which inhalational agent is cardiac output moderately increased?

• A. A Halothane
• B. B Sevoflurane
• C. C Nitrous oxide
• D. D Isoflurane

Answer: (C)

The main concept here is how different inhalational agents affect cardiac output. Most volatile agents cause vasodilation and some degree of myocardial depression, which tends to lower or blunt cardiac output, especially Halothane which can markedly depress the heart. Isoflurane and Sevoflurane also reduce systemic vascular resistance and may modestly depress contractility, so their net effect is often a preserved or slightly decreased cardiac output. Nitrous oxide, in contrast, is relatively cardiostable and can stimulate the sympathetic system, leading to an increase in heart rate and a modest rise in cardiac output. Because it does not significantly depress myocardial contractility and can increase sympathetic tone, nitrous oxide best matches the pattern of a moderate increase in cardiac output compared with the other agents. So, among these options, nitrous oxide is the inhalational agent most likely to produce a moderate increase in cardiac output.

The main concept here is how different inhalational agents affect cardiac output. Most volatile agents cause vasodilation and some degree of myocardial depression, which tends to lower or blunt cardiac output, especially Halothane which can markedly depress the heart. Isoflurane and Sevoflurane also reduce systemic vascular resistance and may modestly depress contractility, so their net effect is often a preserved or slightly decreased cardiac output.

Nitrous oxide, in contrast, is relatively cardiostable and can stimulate the sympathetic system, leading to an increase in heart rate and a modest rise in cardiac output. Because it does not significantly depress myocardial contractility and can increase sympathetic tone, nitrous oxide best matches the pattern of a moderate increase in cardiac output compared with the other agents.

So, among these options, nitrous oxide is the inhalational agent most likely to produce a moderate increase in cardiac output.