Respiratory depression after administration of single-dose neuraxial morphine for post-cesarean delivery analgesia: a retrospective cohort study.

BACKGROUND: Neuraxial administration of long-acting opioid is the "gold standard" for the management of postoperative pain following cesarean delivery. Respiratory depression, however, remains a concerning complication. METHODS: This retrospective single-center study of 4963 patients evaluated the frequency of respiratory depression after neuraxial morphine administration in a post-cesarean delivery population. The spinal dose of morphine varied from 100 to 450 µg intrathecally, and from 3 to 5 mg epidurally. The primary outcome was the initiation of a Rapid Response Team (RRT) event for respiratory failure due to neuraxial opioid in the 24 h following morphine administration. Secondary outcomes studied included oxygen desaturation events (SpO2 <90%), initiation of oxygen therapy and naloxone administration. RESULTS: There were no respiratory RRT events within the study period (95% confidence interval [CI] 0 to 7 per 10 000). There were no desaturation events recorded and no patients received supplemental oxygen therapy or naloxone (95% CI 0 to 7 per 10 000). CONCLUSION: Clinically significant respiratory depression is rare among patients receiving neuraxial morphine for post-cesarean delivery analgesia.

Ultrasound and histological measurements of dividing membrane thickness in twin gestations.

OBJECTIVE: To determine how prenatal ultrasound measurements of dividing membrane thickness correlate with postnatal histological measurements and chorionicity in twin gestations. METHODS: This was a prospective, longitudinal cohort study of twin gestations. Dividing membrane thickness was measured by transabdominal ultrasound, with the insonation beam both parallel and perpendicular to the membrane, in the second or third trimester, depending on when care was established. Ultrasound examinations were performed every 4 weeks following initial assessment until delivery. Measurements of membrane thickness from the first ultrasound examination were compared with histological measurements after delivery. RESULTS: A total of 45 twin pregnancies (32 dichorionic, 13 monochorionic) were included. Mean gestational age at initial ultrasound examination was 24.1 ± 7.3 weeks. Parallel ultrasound measurements of membrane thickness were 1.6 ± 0.8 mm for monochorionic and 2.5 ± 0.9 mm for dichorionic gestations (P = 0.001). Perpendicular ultrasound measurements were 1.6 ± 0.3 mm for monochorionic and 2.2 ± 0.8 mm for dichorionic gestations (P = 0.009). Inter- and intraobserver reliability of ultrasound measurements were 0.847 and 0.950, respectively. Parallel and perpendicular ultrasound measurements correlated better with each other (R = 0.807, P < 0.001) than with histological measurements of membrane thickness (Rparallel = 0.538, P < 0.001; Rperpendicular = 0.529, P < 0.001). Receiver-operating characteristics curve analyses to predict histological membrane thickness > 50th percentile resulted in an area under the curve (AUC) of 0.828 for parallel (P < 0.001) and 0.874 for perpendicular (P < 0.001) measurements with a cut-off value of 1.9 mm for both approaches. The AUCs for parallel and perpendicular measurements to predict dichorionicity were 0.892 (P < 0.001) and 0.823 (P < 0.001) with cut-off values of 1.9 and 1.8 mm, respectively. CONCLUSION: Prenatal ultrasound measurement of twin dividing membrane thickness is positively correlated with postnatal histological measurement. Dichorionicity can be determined by a magnified dividing membrane thickness ≥ 1.9 mm. Measurements with the ultrasound beam parallel to the dividing membrane may be more accurate than perpendicular measurements. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.