$re = '/\b(?:BP:?(?:-Sitting)?|Blood Pressure) \d+/\d+(?: \d+/\d+)*(?: mmHg?)?|B/P - (?:Sys|Dias)tolic \d+|(?:Sys|Dias)tolic Blood Pressure \d+ \w+\b/m';
$str = 'BP 128/80 128/81 128/82
BP 128/80';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php