Ans: C. The cuff should be slowly deflated until the first Korotkoff sound is heard only during expiration(Ref: Harrison 19/e p1621, 1446 18/e p1825; Ganong 25/e p517)The cuff is slowly deflated and the paradoxical pulse is recorded from the point when first Korotkoff sound is heard only during expiration to when it is heard in both expiration and inspiration.Pulsus paradoxus:Quantified using a blood pressure cuff and stethoscope (Korotkoff sounds), by measuring the variation of the systolic pressure during expiration and inspiration.Inflate cuff until no sounds (as is normally done when taking a BP) slowly decrease cuff pressure until systolic sounds are first heard during expiration but not during inspiration, (note this reading), slowly continue decreasing the cuff pressure until sounds are heard throughout the respiratory cycle, (inspiration and expiration) (note this second reading).If the pressure difference between the two readings is >10mm Hg, it can be classified as pulsus paradoxus.