Analgesia after Cesarean section in preeclampsia parturients receiving magnesium sulfate: a retrospective comparison with non-preeclampsia parturients

ABSTRACT

BACKGROUND: Magnesium sulfate (MgSO4) is the first-line therapy for managing preeclampsia in obstetrics. Its perioperative administration has been proved to be an effective analgesic adjuvant, which we investigated in parturients undergoing Cesarean section (C-sec). METHODS: A retrospective chart review examined 504 parturients who underwent C-secs between June 2006 and August 2010, including normal parturients (group N, n = 401) and those diagnosed with preeclampsia (group P, n = 103). A postoperative numeric rating scale (NRS) was used to assess pain, and the number of rescue analgesic administrations and frequency of transfusions were investigated. Perioperative magnesium concentrations were recorded for patients in group P. RESULTS: Patients in group P had longer operation and anesthesia times, and more postoperative admission days than those in group N. The NRS of pain was significantly lower in group P at postoperative day (POD) 1 (4 vs. 5, P < 0.001), and the frequency of rescue drug administration was lower in group P at POD 1 (36.0% vs. 80.3%, P < 0.001) and POD 2 (9.7% vs. 21.1%, P = 0.005) than in group N. Red blood cell transfusions were given more frequently in group P (21.4% vs. 2%, P < 0.001). Pre- and postoperative serum magnesium concentrations in group P were 2.2 (0.5) and 2.1 (0.6) mmol/L, respectively. CONCLUSIONS: Postoperative pain after C-sec was less severe and intravenous patient-controlled analgesia was more efficacious in the preeclampsia group than in the non-preeclampsia group. These findings likely resulted from peripartum intravenous MgSO4 administration in the preeclampsia group.