Nitrous oxide (N2O) has been used for the treatment of labor pains for over 150 years. The longevity of its use in clinical practice can be attributed to its excellent safety profile, ease of administration, and familiarity of use among health-care providers. Sedara is a self-administered 50% N2O, 50% oxygen gas mixture with pain relieving and anxiety reducing properties recently available for use in the United States (US) to treat various painful clnical situations, including labor pains.

In the US, epidural or intravenous administration of narcotic medications is one of the most common and frequently requested treatments for patients experiencing labor pains. Although generally considered safe, complications are common with epidurals, including fetal distress, low blood pressure in the mother, respiratory distress, and headache. In our hospital system, the use of the synthetic intravenous painkiller, Butorphanol, is a mainstay of treatment for labor pains. It too can have undesirable side effects in the mother, including low blood pressure and breathing problems.

Because Sedara has until recently been unavailable in the US, studies comparing its efficacy with other agents for labor pain have been confined to Europe, predominantly in the United Kingdom. Several studies have investigated the efficacy of Sedara versus inhalation and intravenous anesthetics in various countries. We have obtained several Sedara devices for use in the West Penn Allegheny Health System (WPAHS) Department of Anesthesiology and would like to examine its efficacy in our target population of women experiencing pain during early labor.

Hypothesis - Sedara will provide equivalent or superior pain relief among term, adult parturients in early labor (less than 5cm cervical dilation) compared to intravenous butorphanol.

Primary aim - Compare Sedara versus butorphanol in a single-blinded randomized trial with the main outcome measure being reduction in labor pains at various time intervals.

Our findings may be significant in terms of improving safety and efficacy of pain relief among women experienceing labor pains. Given that Sedara has not been previously studied in the US, the results may influence current obstetrical and pain management practices.

Inclusion Criteria:

• Female
• 18 years of age or older
• Presents in active labor
• Full term pregnancy (at least 37 and up to 42 weeks gestation)
• Less than 5 cm cervical dilation on exam

Exclusion Criteria:

• Patients who have received prior regional or opioid analgesia
• Patients who have taken oral analgesics (narcotic or non-steroidal anti inflammatory drugs) within 6 hours prior to presentation