Nitrous Oxide During Labor: Less Pain Relief, High Patient Satisfaction

Nitrous oxide has only recently been adopted in the United States to alleviate labor pain.
Nitrous oxide has only recently been adopted in the United States to alleviate labor pain.

Despite lower reported effectiveness for labor pain, the degree of patient satisfaction in women who received nitrous oxide is similar to that of women who received neuraxial modalities, according to a study described in Anesthesia & Analgesia.1

Although physicians in other countries have used nitrous oxide for decades to alleviate labor pain, this option has only recently been adopted in the United States. Previous research regarding its analgesic effectiveness has been largely inconclusive, and few studies have explored patient satisfaction associated with this modality.2,3 In the current investigation, researchers at Vanderbilt University Medical Center in Nashville, Tennessee, retrospectively examined data collected since their facility began offering self-administered nitrous oxide as an analgesic option in 2011.

Using surveys provided to 6,242 women who delivered vaginally  on the first day postpartum, the researchers sought to assess pain relief and patient satisfaction for 3 different modalities: nitrous oxide (12%), neuraxial analgesia (81%), or both (nitrous oxide followed by neuraxial analgesia, 8%). The effectiveness of pain relief and satisfaction with analgesia care were rated on a scale of 0 to 10 (8-10 = high; 5-7 = moderate; and 0-4 = low).

The analysis revealed the following associations:

  • The odds of high analgesic effectiveness were 90% less in patients who received only nitrous oxide compared with patients who received neuraxial analgesia (odds ratio [OR], 0.10; 95% confidence interval [CI], 0.08−0.12; P <.001). No significant difference in effectiveness was found between the 2 neuraxial anesthesia groups (P =.13).
  • Although high analgesic effectiveness was reported by 92% of patients who received neuraxial analgesia and only one-half of those who received nitrous oxide alone, both sets of patients reported similar levels of satisfaction with their analgesia care.
  • Women who received only nitrous oxide and reported poor analgesia were more likely to report high satisfaction vs patients who received only neuraxial analgesia (OR, 2.5; 95% CI, 1.4−4.6; P =.002).
  • Patients in the nitrous oxide-only group who reported moderate analgesia were more likely to indicate high satisfaction compared with both of the other groups (neuraxial only: OR, 2.2 [95% CI, 1.3−3.8; P =.005]; neuraxial analgesia, OR; 4.4 [95% CI, 1.65−11.6; P =.003]).

“Although pain relief contributes to the satisfaction with labor analgesia care, our results suggest that analgesia is not the only contributor to maternal satisfaction,” wrote the authors. Earlier findings identified “personal expectations, caregiver support, quality of the relationship with her caregiver, and involvement in decision making” as factors that influence women's satisfaction with their experience of childbirth.4

Summary and Clinical Applicability

Although nitrous oxide during labor was associated with inferior pain relief compared with neuraxial analgesia, patients who received both modalities reported similar levels of satisfaction with their analgesia care.

Limitations

The present study is limited by the lack of standard, validated assessment tools to measure maternal satisfaction. 

 

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References

  1. Richardson MG, Lopez BM, Baysinger CL, Shotwell MS, Chestnut DH. Nitrous oxide during labor: maternal satisfaction does not depend exclusively on analgesic effectiveness. Anesth Analg. 2017; 124 (2), 548-53. doi: 10.1213/ANE.0000000000001680
  2. Rosen MA. Nitrous oxide for relief of labor pain: a systematic review. Am J Obstet Gynecol. 2002; 186(5 Suppl Nature):S110-26.
  3. Likis FE, Andrews JC, Collins MR, et al. Nitrous oxide for the management of labor pain: a systematic review. Anesth Analg. 2014; 118(1):153-67. doi: 10.1213/ANE.0b013e3182a7f73c
  4. Hodnett ED. Pain and women's satisfaction with the experience of childbirth: a systematic review. Am J Obstet Gynecol. 2002; 186(5 Suppl Nature):S160-72.
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