**Question:** Card test is done for-

A. Assessment of cardiovascular function
B. Investigation of cardiovascular disorders
C. Evaluation of cardiac output
D. Investigation of pulmonary function

**Correct Answer:** A. Assessment of cardiovascular function

**Core Concept:**
The card test is a clinical examination maneuver used to assess cardiovascular function indirectly. It is based on the principle that a change in heart rate and blood pressure can be elicited by altering the volume and pressure in the thoracic cavity.

**Why the Correct Answer is Right:**
The card test is primarily used to assess cardiovascular function because it involves measuring the reflex changes in heart rate and blood pressure in response to varying intrathoracic pressure. This test helps in evaluating the cardiovascular system's overall efficiency and integrity, as the changes in heart rate and blood pressure are influenced by the heart, blood vessels, and the autonomic nervous system.

**Why Each Wrong Option is Incorrect:**
A. Investigation of cardiovascular disorders (Option B) is a subset of the correct answer, as the card test can be used as a screening tool for cardiovascular diseases. However, the correct answer is broader and covers all aspects of cardiovascular assessment.
C. Evaluation of cardiac output (Option C) is not the primary focus of the card test. The card test evaluates overall cardiovascular function, including cardiac output, but its primary aim is to assess the cardiovascular system's efficiency and reflex responses, not directly cardiac output estimation.
D. Investigation of pulmonary function (Option D) is incorrect because the card test primarily assesses cardiovascular function and not pulmonary function.

**Clinical Pearl:**
The card test is a valuable tool in the assessment of cardiovascular function, especially in patients with suspected cardiovascular disorders. It can help identify abnormalities in heart rate, blood pressure, and reflex responses, providing valuable information for clinical decision-making and diagnosis. However, it is essential for clinicians to have a good understanding of cardiovascular anatomy, physiology, and reflex mechanisms to interpret the results accurately.