Respiratory effects and amnesia after premedication with morphine or lorazepam

Area of Science:

• Anesthesiology
• Pharmacology
• Respiratory Physiology

Background:

• Benzodiazepines are commonly used for sedation.
• Morphine is a standard analgesic and premedicant.
• The respiratory effects of lorazepam require further elucidation.

Purpose of the Study:

• To compare the respiratory effects of lorazepam and morphine as premedicants.
• To assess the impact of these drugs on carbon dioxide sensitivity.
• To evaluate the amnesic effects of lorazepam.

Main Methods:

• A comparative study involving 20 patients receiving either morphine or lorazepam intramuscularly.
• Respiratory effects were measured using a rebreathing method to assess carbon dioxide response.
• Amnesia was evaluated through patient recall.

Main Results:

• Morphine significantly decreased carbon dioxide sensitivity (S) by 47%.
• Lorazepam increased carbon dioxide sensitivity (S) by 27%.
• Lorazepam induced amnesia in all patients for 4-8 hours, while morphine did not.

Conclusions:

• Lorazepam demonstrates a unique effect on respiratory drive, increasing carbon dioxide sensitivity.
• The amnesic properties of lorazepam suggest its utility in procedures requiring patient unawareness.
• Lorazepam warrants further investigation for applications in obstetrics and other fields needing sedation without respiratory compromise.