Dexamethasone for Post-cesarean Delivery Pain

The purpose of this study is to compare post-cesarean section consumption of pain medication between two groups of patients undergoing scheduled cesarean section at term gestation who receive a single-dose of intraoperative steroid (dexamethasone 8 milligrams) versus placebo at 24 hours after surgery. The hypothesis is that a single perioperative dose of dexamethasone 8 mg will significantly reduce postoperative opioid consumption at 24 h in women having cesarean delivery under spinal anesthesia.

Steroids have been used to reduce inflammation and tissue damage in a variety of conditions, have potent immunomodulatory effects, and are a mainstay in the treatment of acute allograft rejection. Dexamethasone has been shown to be a safe and effective anti-emetic therapy for patients undergoing cesarean section surgery with spinal anesthesia containing morphine. However, recent evidence suggests that dexamethasone may also play a role in reducing post-operative pain and opioid consumption. Early studies in patients undergoing dental procedures showed that glucocorticoids were effective in reducing postoperative pain and edema. Multiple recent studies have also investigated the potential analgesic benefit of a single perioperative dose of dexamethasone, but the results have been inconsistent. The effect of single-dose, intraoperative, intravenous dexamethasone therapy on post-operative pain and opioid consumption has not yet been studied in patients undergoing cesarean section. Pain is a significant source of morbidity for many women following cesarean section, and has serious consequences beyond the immediate post-operative period. Patients with poorly-controlled pain may have difficulty with ambulation that can lead to atelectasis, pneumonia, and venous thromboembolism. Poor maternal pain control may also affect the infant by interfering with bonding and breastfeeding. Reduction of post-operative opioid consumption is desirable because it may also reduce the incidence of opioid-induced side effects such as sedation, constipation, nausea, vomiting and pruritus. Some evidence suggests that the severity of post-operative pain following cesarean section may predict progression to chronic pain, and postpartum depression. Although 10 to 18% of women who undergo cesarean section will experience chronic pain following surgery, it is difficult to predict those patients who will experience this complication. Recent investigations have shown that patient responses to standardized painful stimuli prior to surgery help predict severity of post-operative pain and possibly progression to chronic pain. This type of information could potentially help to tailor the clinical management of patients at risk for severe and/or chronic post-operative pain to improve outcomes for these patients. Landau and colleagues have described a simple and minimally-invasive method of assessing response to noxious stimuli using a von-Frey filament to obtain a mechanical temporal summation score.

Anesthesia, Cesarean Section, Pain, Postoperative, Postoperative Nausea and Vomiting, Dexamethasone, Injections, Spinal, morphine

The primary outcome will be the cumulative morphine consumption at 24 h in the two study groups. All postoperative opioids were converted to IV morphine equivalents using the following conversion factors: 100 micrograms IV = 10 mg IV morphine, 20 mg oxycodone po = 10 mg IV Morphine

Pain scores were measured using a numeric rating scale with a range from 0 to 10, with 0 meaning no pain and 10 indicating the most severe pain.

Time in minutes from admission to PACU to the first request by the patient for oral oxycodone (analgesia) administration for pain

The secondary outcome was the cumulative morphine consumption at 48 h in the two study groups. All postoperative opioids were converted to IV morphine equivalents using the following conversion factors: 100 micrograms IV = 10 mg IV morphine, 20 mg oxycodone po = 10 mg IV Morphine

Pain scores were measured using a numeric rating scale with a range from 0 to 10, with 0 meaning no pain and 10 indicating the most severe pain.

Pain scores were measured using a numeric rating scale with a range from 0 to 10, with 0 meaning no pain and 10 indicating the most severe pain.

Mechanical temporal summation (MTS) was assessed using A 180 g Von Frey Filament was applied to the volar aspect of the dominant forearm, and subjects were asked to rate pain scores (NRS 0-100, 0 = no pain and 100= worst pain possible) after the 1st and 11th tap. A difference < 1 was recorded as MTS negative, and a difference > or = 1 was recorded as MTS positive.

Patients answered a questionnaire at 8 weeks to determine whether they still had persistent surgical site pain 8 weeks following surgery

Patients answered a questionnaire at 6 months to determine whether they still had persistent surgical site pain 6 months following surgery

Mechanical temporal summation (MTS) was assessed using A 180 g Von Frey Filament was applied to the volar aspect of the dominant forearm, and subjects were asked to rate pain scores (NRS 0-100, 0=no pain and 100=worst pain possible) after the 1st and 11th tap. A difference < 1 was recorded as MTS negative, and a difference > or = 1 was recorded as MTS positive.

Incidence of intraoperative nausea and vomiting and need for rescue antiemetics were recorded during surgery. Patient who reported a nausea score on a 11 point NRS where 0=no nausea and 10 = the worse nausea possible. Patients who retched or vomited were reported to have vomited. Patients receiving any antiemetic during surgery were recorded as those requesting ( needing) rescue antiemetic.

pruritus was defined as patients reporting a pruritus score of greater than o on a numerical rating scale with o=no pruritus and 10= worst pruritus

Incidence of postoperative pruritus was calculated based on their postoperative pruritus scores measured at 2 hours, 24 hours and 48 hours. Median of the scores recorded at three time points was calculated. If median score >0 then patient experienced postoperative pruritus.

Need for intraoperative analgesic supplementation was determined by patients who required intraoperative analgesics for pain

Patients who had experienced Postoperative nausea either reported postoperative nausea scores at 2, 24 and 48 hours from >0, reported an episode of vomiting or received an antiemetic were recorded as experiencing PONV. Patients who received at least one rescue antiemetic postoperatively were recorded as requiring a rescue antiemetic

Patients were assessed for signs of surgical wound inspection by the obstetric team following surgery

Blood Pressure Measurements Obtained by the Standard of Care Non-invasive Blood Pressure Monitor Compared With the Continuous Noninvasive Arterial Pressure (CNAP)

Inclusion Criteria: American Society of Anesthesiology (ASA) class 1, 2 and 3 Gestational age > 37 weeks scheduled for elective cesarean delivery spinal or combined spinal epidural anesthesia 18 years or older speak English Exclusion Criteria: BMI > 45 kg/m2 Diabetes Mellitus (Type 1, 2 and gestational) mild or severe preeclampsia history of intravenous drug or opioid abuse previous history of chronic pain syndrome history of opioid use in the past week receipt of an antiemetic within 24 h prior to surgery Non-English speaking

Griffiths JD, Gyte GM, Popham PA, Williams K, Paranjothy S, Broughton HK, Brown HC, Thomas J. Interventions for preventing nausea and vomiting in women undergoing regional anaesthesia for caesarean section. Cochrane Database Syst Rev. 2021 May 18;5(5):CD007579. doi: 10.1002/14651858.CD007579.pub3.