Colonoscopy Using Nitrous Oxide- A Pilot Study in the USA

Exclusion Criteria

• •High ASA risk (IV/ \>)
• •History of chronic pain
• •Allergy to N2O or opioid or BDZ
• •No consent
• •Recent head injury with impairment of consciousness or Intracranial / Middle Ear surgery within the previous 6 months with or without residual deficits.
• •Pneumothorax, air embolism
• •Decompression sickness or within 48 hours of an underwater dive
• •Severe emphysema with bullae
• •Gross abdominal distension with suspicion for bowel obstruction
• •Intoxication
• •Maxillofacial injuries (where patient unable to administer the drug using a mouthpiece/mask, or there is the risk of causing further damage to facial wounds and there may also be a significant risk of blood inhalation)
• •Patients with chronic pulmonary disease for whom an inspired oxygen concentration of more than 28% oxygen might be dangerous
• •Patients on Methotrexate
• •Where patients need assistance to hold the mask or mouthpiece.
• •Retinal surgery within the last three months
• •Any patient who does not otherwise clinically qualify for standard sedation methods (i.e., those who require general anesthesia)