During World War I, Piñero helped establish a hospital in Puerto Rico to attend soldiers who had contracted the swine flu.

Spain ceded Puerto Rico to the United States in accordance with the agreement reached in the 1898 Treaty of Paris, which officially ended the Spanish–American War.

[2] After earning her degree, Piñero returned to Puerto Rico and set up her medical and anesthesia practice in what was then the town of Río Piedras (it is now a section of San Juan).

[1] By 1918, the Army realized that there was a shortage of physicians specializing in anesthesia, a low-salary specialty required in the military operating rooms.

Piñero and four male colleagues received orders to open a 400-bed hospital in Ponce, Puerto Rico, to care for the patients who had been infected with influenza, known also as "the Swine Flu."

[4] The Swine Flu had swept through Army camps and training posts around the world, infecting one quarter of all soldiers and killing more than 55,000 American troops.

[6][7] Little is known of Piñero's later years, with the exception that she was one of the leaders of the local Women's Civic Club and that she worked for the Puerto Rico Department of Health.