$re = '/\b(?:BP:?(?:-Sitting)?|Blood Pressure) \d+/\d+(?: mmHg?)?|B/P - (?:Sys|Dias)tolic \d+|(?:Sys|Dias)tolic Blood Pressure \d+ \w+\b/m';
$str = 'BP 98/60
BP 108/60
BP 96/60
BP 120/75
Blood Pressure 106/63
B/P - Systolic 104
B/P - Diastolic 72
BP-Sitting 109/70 mmH
BP: 101/72
Systolic Blood Pressure 100 mmHg
Diastolic Blood Pressure 68 mmHg';
preg_match_all($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