Objective To review and analyze the statistics of laboratory critical values in the Department of Cardiovascular Surgery in order to improve the procedures of dealing with these values and provide references for the enhancement of the nursing level. Methods We retrospectively analyzed laboratory critical values of 236 inpatients in the Department of Cardiovascular Surgery from April 2013 to April 2014. General data of the patients including the type of critical values, the critical value, distribution, clinical processing time and complications related to the critical values. Results A total of 208 laboratory critical values of 185 inpatients were analyzed including abnormal blood potassium was involved in 99 (47.60%); abnormal blood glucose was involved in 13 (6.25%); abnormal blood sodium was involved in 11 (5.29%); abnormal blood troponin was involved in 13 (6.25%); and 72 cases had other kinds of critical values (34.62%). A total of 136 critical values were closely related to the Department of Cardiovascular Surgery. Among them, 60 cases had a processing time of 15 minutes or shorter. After re-examination, 16 were confirmed to be fake critical values; and 11 critical values did not need to be treated according to the condition of the patients. There were altogether 27 cases of complications related to critical values, including 23 cases of arrhythmia related to abnormal blood potassium, 2 cases of abnormal muscle strength caused by abnormal blood sodium, and 2 cases of hypoglycemia. After the critical values were handled, related complications disappeared without any recurrence. Conclusions Perfect regulatory regime and process of recording and handling laboratory critical values are important for nurses in our department to carry out more accurate measures in treating these critical values including abnormal blood potassium, blood glucose, blood sodium, and blood troponin, etc. In order to continuously improve medical and nursing quality, nurses should pay more attention to the identification and treatment of laboratory critical values.