To compare two different timings for the performance of the Valsalva maneuver (VM) using an infusion of agitated saline solution with blood as contrast agent (CA) to right-to-left shunt (RLS) screening.
42 patients were submitted to a standardized contrast-enhanced transcranial doppler (cTCD) to screen for right-to-left shunt (RLS). cTCD technique was done with two different moments of the VM:  the CA injection during the VM (CAduringVM test);  the CA injection before the VM (CApreVM test).
Positive MCA tests were observed in 47 (56%) CAduringVM tests and in 50 (59.5%) CApreVM tests, p=0.64. There was an almost perfect agreement for the positive tests between the CAduringVM and CApreVM test, r s=0.829 (95% CI 0.61-1.00, p<0.001).
The present study demonstrates that there is no significant difference in the results of RLS screening by cTCD when two different moments of VM were done.