Date of this Version


Document Type

DNP Project



Title: Adverse Outcomes of Mild Hypocapnia During General Anesthesia: An Evidence-Based Education Module

Impact Statement: Promoting normocapnia practices by maintaining EtCO2 levels of 40 mmHg or above during general anesthesia will ultimately enhance mortality rates and patient outcomes

Background: There are few research articles on low intraoperative end-tidal carbon dioxide (EtCO2) levels in postoperative mortality. This study examines the correlation between intraoperative EtCO2, length of hospital stay (LOS), and mortality in individuals receiving general anesthesia.

Objective: The relevance of this project is to improve surgical patient outcomes by decreasing mortality and length of hospital stay. At the end of this project, anesthesia providers will see strong evidence for the application of normocapnia (EtCO2 levels of 40 mmHg or above) during the intraoperative management of patients undergoing surgical procedures under general anesthesia.

Methods: A systematic search utilized Ovid, Medical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), and ProQuest. A pretest survey assessed the providers’ initial knowledge and attitudes regarding intraoperative EtCO2. This step was followed by a PowerPoint presentation and a post-test survey.

Results: The examination of nine research studies was determined to be credible. During general anesthesia (GA), the included studies focused on patient results with intraoperative EtCO2 levels ranging from 30-35 mmHg to 40 mmHg or higher.

Discussion: Most patients with EtCO2 less than 35 mmHg experienced a hospital length of stay of more than six days compared to individuals with EtCO2 greater than 35 mmHg. Moreover, decreased EtCO2 is related to adverse outcomes regardless of blood pressure, representing a state of compensation for decreased cardiac output, by raising peripheral vascular resistance while maintaining blood pressure.

Conclusion: Several studies established that normocapnia is beneficial and should be considered a routine intervention during GA. Hypocapnia and the hyperventilation necessary to create it are detrimental. Additionally, increased mortality and LOS are proven unfavorable consequences of low EtCO2. Mild hypercapnia can improve oxygen supply by improving tissue perfusion, increasing carbon dioxide levels, and vasodilation.