参考答案：A

解析：An NG tube that fails to drain during the postoperative period after gastrectomy should be reported to the physician immediately. The tube may be occluded, which could increase pressure on the suture line because fluid isn't draining adequately. Repositioning or irrigating the tube in a client who has bad gastric surgery can disrupt the anastamosis. Increasing the level of suction may cause trauma to GI mucosa or the suture line.