BACKGROUND High-flow nasal oxygenation (HFNO) for pre-oxygenation in rapid sequence induction (RSI) has only been assessed in volunteer parturients without intubation. OBJECTIVES To evaluate the efficacy of HFNO in comparison with the conventional facemask for oxygenation during RSI for caesarean section under general anaesthesia. SETTING Operating room in a tertiary hospital. DESIGN Prospective randomised, controlled study. PARTICIPANTS Thirty-four healthy parturients undergoing general anaesthesia for caesarean section. INTERVENTIONS Parturients were randomly assigned to HFNO or standard facemask (SFM) group. MAIN OUTCOME MEASURES The primary outcome measure was the PaO2 immediately after intubation. Secondary outcomes included lowest saturation throughout the intubation procedure, end-tidal oxygen concentration (EtO2) on commencing ventilation, blood gas analysis (pH, PaCO2), fetal outcomes and intubation-related adverse events. RESULTS PaO2 in the HFNO group was significantly higher than that in SFM group (441.41 ± 46.73 mmHg versus 328.71 ± 72.80 mmHg, P < 0.0001). The EtO2 concentration in the HFNO group was higher than that in the SFM group (86.71 ± 4.12% versus 76.94 ± 7.74%, P < 0.0001). Compared to baseline, PaCO2 immediately after intubation also increased significantly in both groups (HFNO group: 30.87 ± 2.50 mmHg versus 38.28 ± 3.18 mmHg; SFM group: 29.82 ± 2.57 mmHg versus 38.05 ± 5.76 mmHg, P < 0.0001), but there was no difference in PaCO2 between the two groups. There was no difference in lowest saturation, intubation times, duration of apnoea, pH value or fetal outcomes. CONCLUSIONS Compared with SFM, HFNO provided a higher PaO2 and EtO2 immediately after intubation in parturients. HFNO is safe as a method of oxygenation during RSI in parturients undergoing general anaesthesia for caesarean section. TRIAL REGISTRATION Clinical trial ChiCTR1900023121.

BACKGROUND: Spinal anesthesia, which is commonly used in cesarean deliveries, is often difficult to perform in obese parturients because of poorly palpable surface landmarks and positioning challenges. This study aimed to evaluate the benefits of ultrasound-assisted technology for performing spinal anesthesia in obese parturients. METHODS: Parturients with a body mass index (BMI) ≥30 kg/m2 scheduled for elective cesarean delivery were randomized to undergo spinal anesthesia using the conventional landmark location technique (landmark group, n = 40) or prepuncture ultrasound examination (ultrasound group, n = 40). All participants underwent spinal anesthesia in the lateral position. The primary outcome was the first-attempt success rate. Secondary outcomes were the number of skin punctures and needle passes, procedure times, patient satisfaction, changes in the intended interspace, and incidence of complications. RESULTS: The ultrasound group had a significantly higher first-attempt success rate (87.5% vs 52.5%; P = .001), fewer cases requiring >10 needle passes (1 vs 17; P < .001), and fewer skin punctures and needle passes (P < .001 for both). There was no statistically significant difference in the time taken to identify the needle insertion site between the 2 groups (202.5 vs 272.0 seconds; P = .580). Both the spinal injection time and total procedure time were significantly longer in the landmark group (P < .001). Patient satisfaction scores were significantly higher in the ultrasound group (P = .001). Among patients with BMI between 30 and 34.9 kg/m2, there was no statistically significant difference in the first-attempt success rate (P = .407), number of cases with >10 needle passes (P = .231), spinal injection time (P = .081), or total procedure time (P = .729); however, more time was required to identify the needle insertion site in the ultrasound group (P < .001). For patients with BMI between 35 and 43 kg/m2, the ultrasound group had a significantly higher first-attempt success rate (P ≤ .041), fewer cases with >10 needle passes (P ≤ .01), and shorter procedure times, including the time required to identify the needle insertion site (P < .001). CONCLUSIONS: Prepuncture ultrasound examination can facilitate spinal anesthesia in the lateral position in obese parturients (35 kg/m2 ≤ BMI ≤ 43 kg/m2) by improving the first-attempt success rate, reducing the number of needle passes and puncture attempts, shortening the total procedure time, and improving patient satisfaction.

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The present study suggests that combined magnesium sulfate and local anesthetics in perineural nerve blocks provided better analgesic efficacy. For it prolongs the postoperative duration time of analgesia, sensory and motor block without increasing the short-term side effects. Magnesium sulfate may be a promising analgesic for perineural nerve blocks, but further studies are required to validate our results.