Jan 6 (Reuters) - Medical device maker Stryker Corp said on Thursday it had agreed to acquire digital care platform Vocera Communications Inc (VCRA.N) for about $2.97 billion. Vocera shares were up nearly 27% at $78.63 before the bell, just shy of the offer price of $79.25 per share. Founded in 2000, Vocera caters to nearly 1,900 hospitals, allowing healthcare workers to communicate and collaborate with co-workers and engage with patients and their families. The deal is expected to close in the first quarter of this year and is estimated to have a neutral impact on net earnings per diluted share in 2022, Stryker said. Stryker shares were down nearly 1% at $270 in light premarket trading.