Blood carbon dioxide tension changes during hysteroscopy

Area of Science:

• Gynecologic Surgery
• Pulmonary Medicine
• Anesthesiology

Background:

• Hysteroscopy utilizes distending media like carbon dioxide (CO2), nitrous oxide (N2O), or Hyskon.
• Gaseous distension methods vary in pressure and volume control, potentially impacting patient physiology.

Purpose of the Study:

• To evaluate the physiological effects of different gaseous distending media and delivery systems during hysteroscopy.
• To determine the safest and most effective gaseous medium and insufflation technique for hysteroscopy.

Main Methods:

• Group 1: 27 patients received N2O via a constant-pressure, variable-volume laparoscopy insufflator; arterialized venous blood samples monitored PCO2.
• Group 2: 24 patients received gaseous media via a constant-volume, variable-pressure source; PCO2 changes were assessed.
• Patient outcomes, including cardiovascular events and PCO2 levels, were recorded.

Main Results:

• N2O insufflation with a constant-pressure device significantly increased PCO2, linked to increased physiologic dead space.
• One patient in Group 1 experienced cardiovascular collapse, likely due to N2O pulmonary emboli.
• Using a constant-volume, variable-pressure gas source resulted in minimal arterial PCO2 changes.

Conclusions:

• Carbon dioxide (CO2) is preferable to nitrous oxide (N2O) for hysteroscopy when a gaseous medium is indicated.
• Gaseous media for hysteroscopy should be introduced using a constant-volume, variable-pressure gas source to minimize physiological risks.
• The choice between gaseous and liquid distending media depends on endometrial status.