Cardiac catheterization is a diagnostic procedure that is performed to diagnostic or provide therapeutic options at various stages of congenital heart disease patients at any age, these diagnostic procedures may require prolonged immobility of the patient, so most require being under sedation and/or general anesthesia. However, sedation can generate an increase in arterial CO2 (PaCO2) and the hypercapnia can alter the measurements obtained during the procedure and increase the risk of complications such as pulmonary hypertension or hypoxemic crises that worsen the outcomes in this type of patients. The objective of this study is to describe the changes in arterial CO2 in patients who are taken to diagnostic catheterization under sedation. Results: A total of 200 patients were collected for the study during the period of January 2019 to July 2021 who were taken to cardiac catheterization under sedation and found that there was no significant increase in mean PaCO2 at the start and end of the procedure (38.6 mmHg vs 39.3 mmHg). Postoperative mortality was 1.5% (3 patients), where one patient died from complete AV block, another from hemorrhage massive and the last due to exacerbated heart failure in the ICU. 4 patients (2%) required Invasive mechanical ventilation (IMV) and 14 patients (7%) required a Care Unit Intensive care (ICU) postoperative. Conclusions: the use of sedation in patients with heart disease who are taken for catheterization may be a safe technique that does not significantly affect arterial CO2 and parameters hemodynamics that are required for the variables that are collected in this procedure diagnosis
