Dear First name / Colleague, Happy Thanksgiving from your SafePartum Team! This month: - The Clinical Corner spotlights dexmedetomidine as a treatment for post-neuraxial shivering during cesarean delivery. Continue scrolling to read!
- Join us February 6 in San Francisco for an all-day workshop at the SMFM Annual Meeting!
- Check out a Bonus Episode of Partum the Interruption! Dr. M and former SOAP President Dr. Ruth Landau of Columbia University discuss the role of the OB Anesthesiologist in cases of inadequate neuraxial blockade during cesarean delivery.
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Speakers: Luis Pacheco, MD (MFM, OB, Critical Care) Amir Shamshirsaz, MD (MFM, OB, Critical Care) Michaela Farber, MD (OB Anesthesiology) Ruth Landau, MD (OB Anesthesiology) Grace Lim, MD (OB Anesthesiology) Vibha Mahendra, MD (OB Anesthesiology) |
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Should we be using IV Dexmedetomidine to reduce shivering during cesarean delivery? |
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More than half of patients experience noticeable shivering following spinal or epidural anesthesia, often severe enough to cause patient distress and/or interfere with the monitoring of vital signs. The intravenous opiate meperidine is generally the treatment of choice for peri-anesthetic shivering, but concerns around respiratory depression and sedation in both mom and neonate make it a questionable choice in obstetrics. Dexmedetomidine, a highly selective alpha 2 agonist, is thought to lower shivering thresholds via transmembrane G protein adrenoreceptors in the periphery, brain, and spinal cord. Though it is considered safe and effective in obstetrics, ideal dosing has not been established. A 2019 study of 80 patients by Lamontagne et al [1] found that 30mcg IV dexmedetomidine reliably stopped noticeable shivering (visible muscle activity) in 90% of patients within 10 min, compared with 22.5% in a control group. However, clinical experience suggests that a single bolus of 30mcg dexmedetomidine is often accompanied by dry mouth and maternal sedation. To illustrate whether a lower dose could provide the same benefit with fewer side effects, Sween et al published the following study in 2021 [2]: |
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In this study, 85 adult women with singleton pregnancies undergoing scheduled cesarean delivery (CD) under spinal or combined spinal-epidural anesthesia were included. Patients with unscheduled CD, intraoperative uterine atony requiring secondary uterotonics, hemorrhage > 1000mL, chronic opioid use, history of chronic nausea or itching in pregnancy were excluded. - Design: Randomized Controlled Trial: 2 arms
- Patients were randomized to receive either IV Dexmedetomidine or IV saline immediately following delivery & administration of oxytocin.
- Intervention: IV dexmedetomidine 10 mcg bolus over 10 min
- Control: IV saline bolus over 10 min
- All IV fluids administered were warmed to 41C and operating room temperature was standardized to 20C.
- Outcomes:
- Primary: Patient-rated subjective shivering score by visual analog scale (VAS) at 30 and 60 min after arrival to the PACU
- Secondary:
- Patient scores for: nausea, pain, itching, dry mouth & sedation
- Observer-rated scores for: shivering, scratching & sedation
- Results:
- Patient-rated VAS shivering scores were lower in the dexmedetomidine group at both 30 and 60 min compared to placebo (p= 0.0002)
- No significant differences between dexmedetomidine vs placebo in patient-rated VAS scores for nausea, sedation, pruritis, dry mouth, or pain at 30 or 60 min
- No significant differences between dexmedetomidine vs placebo in observer-rated incidence of shivering, sedation, or scratching at baseline, 30, or 60 min
- Side effects:
- Prevalence of vomiting and post-op medications for pain, nausea and GI symptoms were similar between groups
- Naloxone for pruritis was given less frequently to the dexmedetomidine group (14% vs 34%, p = 0.04)
Our impressions: In this 2021 publication, Sween et al demonstrated that a single 10mcg IV bolus of dexmedetomidine resulted in a statistically significant reduction in patient-reported shivering at 30 min and 60 min post-PACU arrival, but not observer-reported shivering. As predicted, there was also no increase in side effects such as sedation or dry mouth. Notably, interference with vital sign monitoring was not reported. The time points chosen in this study (30 & 60 min post-PACU arrival) are a bit puzzling, as by 30 or 60 min post-PACU arrival, the sympatholytic and vasodilatory effect of the neuraxial block should already be waning. A more clinically relevant outcome for future studies would be the number of minutes to cessation of shivering after dexmedetomidine administration, as was evaluated in the study by Lamontagne et al. Other things to ponder… - An optimal dose of IV dexmedetomidine for shivering has yet to be established, but it may be reasonable to begin with 10mcg and increase the dose up to 30mcg based on the patient’s symptoms and side effects.
- Further studies are needed to determine whether dexmedetomidine is safe for immediate post-neuraxial (pre-delivery) administration.
- Neuraxial administration of dexmedetomidine is an attractive strategy, but there is limited safety data to support or guide its use.
- Shivering serves a physiologic purpose; should we be medically manipulating shivering thresholds in all patients?
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1 Lamontagne C, Lesage S, Villeneuve E, Lidzborski E, Derstenfeld A, Crochetière C. Intravenous dexmedetomidine for the treatment of shivering during Cesarean delivery under neuraxial anesthesia: a randomized-controlled trial. Can J Anaesth. 2019 Jul;66(7):762-771. English. doi: 10.1007/s12630-019-01354-3. Epub 2019 Apr 3. PMID: 30945105. 2 Sween LK, Xu S, Li C, O'Donoghue MA, Ciampa EJ, Kowalczyk JJ, Li Y, Hess PE. Low-dose intravenous dexmedetomidine reduces shivering following cesarean delivery: a randomized controlled trial. Int J Obstet Anesth. 2021 Feb;45:49-55. doi: 10.1016/j.ijoa.2020.11.004. Epub 2020 Nov 17. PMID: 33293185. |
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Wishing you all a happy & healthy holiday season. with gratitude, |
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