$re = '/"Case_Status__c":"(?<status>.*?)".*?"Emergency_Outage_Case__c":(?<emgcase>.*?)}]}/m';
$str = '{"searchRecords":[{"attributes":{"type":"Case","url":"/services/data/v43.0/sobjects/Case/500e000000DmsKDAAZ"},"Id":"500e000000DmsKDAAZ","Case_Status__c":"Open","Emergency_Outage_Case__c":true}]}';
preg_match_all($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