My neighbor’s warning rang in my ears as the hospital ICU doors swung open. “Don’t look at her right after,” he had cautioned. “She’s going to look like she’s dead.”

My mother’s latest open heart surgery had ended an hour ago. For the second time in 11 years, surgeons had sawed her sternum in half and spread it apart to repair the damaged organ. During the five-hour valve replacement, her heart was stilled for a time, blood pumped through her body by a cardiopulmonary bypass (heart-lung) machine — a high-tech autopilot for vital organs that first kept a cat alive for 26 minutes more than 75 years ago.

Today, the brainchild of Philadelphia surgeon John Heysham Gibbon stands in for hearts and lungs in operating theaters around the world. The pump is controlled by a perfusionist, an artist who tunes its rhythms in the symphony that is cardiac surgery — not unlike the deep, rich tones a double bass lends to a jazz orchestra.

Only two family members were permitted at my mother’s bedside post-surgery. On the ICU wall, a sign asked for quiet: ‘Healing in Progress.’ As we waited outside her curtained cubicle for permission to enter, I considered ceding my spot to my sister. I did not know if I could bear the sight of my mother hitched to every kind of tube and monitor, the death’s door scenario my neighbor had prepped me for.

But when the curtain swung open, I stepped inside with my father, eyes resolutely avoiding the thick plastic hose protruding from her neck, the drops of blood on the floor below the bed. My mother’s face was pale and slightly swollen, but the beeps emanating from overhead monitors signaled she was very much alive.

In fact, she’d done very well for a ‘reopen,’ the staff said, referring to her earlier operation. A few days later, minus most of her hospital hardware, my mother was stepped down to a cardiac bed in the prominent New York hospital. From a pair of chairs one afternoon, we watched the sightseeing boats glide up the East River. Eventually, my mother tired, and her head nodded toward her bruised chest, which had been Steri-Stripped shut.

I thought again of that heart-lung pump, of the myriad patients who enter its technology-induced twilight, the sort of corporal suspension, every day. One can only wonder where the body and spirit reside during its stop-motion limbo.