The efficacy of 2 doses of epidural morphine for postcesarean delivery analgesia: a randomized noninferiority trial.

BACKGROUND: A single dose of epidural morphine is effective in reducing pain after cesarean delivery but is associated with adverse effects. In this study, we sought to establish whether half the traditional dose of epidural morphine, when administered as part of a multimodal analgesia regimen after cesarean delivery, was associated with noninferior analgesia and fewer adverse effects. METHODS: Ninety term parturients undergoing cesarean delivery under epidural anesthesia were enrolled in this randomized, double-blinded, noninferiority study. Patients were randomly allocated to receive either 3 mg epidural morphine or, half this dose, 1.5 mg epidural morphine. In addition, subjects received regular systemic ketorolac and acetaminophen. Rescue analgesia (oral oxycodone) was administered for breakthrough pain. The primary outcome was the difference between groups in total opioid consumption (measured in median IV morphine equivalents) within the first 24 hours. A prespecified noninferiority margin of 3.33 mg was used. Secondary outcomes included total opioid consumption from 24 to 48 hours, numerical rating scale pain scores, time to first request for analgesics, overall pain relief, maternal satisfaction, quality of recovery, and adverse effects. RESULTS: Data were analyzed for 87 participants. Noninferiority was demonstrated as the difference in median 24-hour opioid consumption between the 1.5 mg epidural morphine (EM) and 3 mg EM groups was 0 mg (1-sided 95% confidence interval [CI], 2.5 mg), which was less than the prespecified noninferiority margin of 3.33 mg. No significant differences were found between groups in the median 24- to 48-hour opioid consumption or the median total opioid consumption within 48 hours. Pain scores, overall pain relief, and satisfaction at 24 and 48 hours were not significantly different between groups. The 1.5 mg EM group had a lower incidence of moderate and severe pruritus at 6 and 12 hours (relative risk [RR] 0.44, 95% CI, 0.2-0.9 and RR 0.41, 95% CI, 0.2-0.8, respectively) and had less nausea and vomiting at 6 hours (RR 0.22, 95% CI, 0.05-0.9). There was no difference in average pain scores at 12 weeks between the 2 groups. CONCLUSION: When used as part of a multimodal analgesia regimen, 1.5 mg epidural morphine provided noninferior postcesarean analgesia and caused fewer adverse effects compared with 3 mg epidural morphine.

Inferior vena cava assessment in term pregnant women using ultrasound: A comparison of the subcostal and right upper quadrant views.

Point-of-care ultrasound can be used at the bedside to assess the haemodynamic status and fluid responsiveness of a pregnant woman. Previous studies demonstrated that views from the apical and parasternal windows are readily obtainable in labouring women. However, using the subcostal window to assess the inferior vena cava can be challenging because of the gravid uterus. A potential alternative is the right upper quadrant transhepatic window. We sought to compare visualisation of the inferior vena cava via the subcostal and right upper quadrant windows, in full-term pregnant women. This was a prospective pilot study carried out in a tertiary academic obstetric centre. Thirty pregnant non-labouring women at full term were recruited. In each patient, the inferior vena cava was visualised through both the subcostal and the right upper quadrant windows. Time to acquire each image, acquisition success rates and ease of obtaining images were compared for both approaches. Image quality was then reviewed and rated by two independent expert reviewers. There was a significant difference in the time required to obtain each view; subcostal median (interquartile range): 52 (35-59) seconds, right upper quadrant median (interquartile range): 23 (11-55) seconds (P=0.0045). Operator-defined successful image acquisition was 100% for the right upper quadrant window compared to 80% for the subcostal window. Ease of obtaining the view, as rated by the operator, was significantly easier in the right upper quadrant window compared to the subcostal window (P <0.0001). Both reviewers independently rated image adequacy to be significantly greater in the right upper quadrant window (73% and 57%) compared to the subcostal window (40% and 10%) (P=0.0213 and P=0.0005, respectively). Inter-rater agreement ranged between good (Cohen's kappa coefficient 0.64) for right upper quadrant windows to fair (Cohen's kappa coefficient 0.29) for subcostal windows. Inferior vena cava visualisation in term pregnant patients may take less time, be easier and provide better quality images when the right upper quadrant window is used compared to the subcostal window.