Abstract Background and objectives: Abdominal Hysterectomy (AH) is associated with significant inflammatory response and can result in moderate to severe postoperative pain. This study aimed to evaluate the efficacy of magnesium infusion in reducing postoperative pain and analgesic consumption after AH under spinal anesthesia with Intrathecal Morphine (ITM). Method: Eighty-six patients were included in this clinical, controlled, randomized, double-blind study. Patients received in Group Mg, MgSO4 50 mg kg−1 for 15 minutes followed by 15 mg kg−1 h−1 until the end of the surgery; and in Group C, (control) the same volume of isotonic saline. Both groups received 100 µg of ITM. All patients received dipyrone + ketoprofen intraoperatively and postoperatively, and dexamethasone intraoperatively only. We evaluated the intensity of pain, tramadol consumption, and adverse events 24 hours postoperatively. Results: Serum magnesium concentrations were higher in Group Mg at the end, and one hour after the operation (p = 0.000). Postoperative pain scores were reduced in Group Mg at 6 hours at rest and on movement (p < 0.05). Tramadol consumption did not show a statistically significant difference between Group Mg and Group C (15.5 ± 36.6 mg and 29.2 ± 67.8 mg respectively, p = 0.53). Hemodynamic variables, the incidence of pruritus, nausea, and vomiting were similar in the two groups. Conclusion: Infusion of MgSO4 during AH undergoing spinal anesthesia with ITM reduced at 6 hours at rest and on movement. More studies should be performed to evaluate the potential antinociceptive effect of MgSO4 in scenarios where a multimodal analgesia approach was employed.

Resumo Justificativa e objetivos: As gestantes são consideradas pacientes de risco para aspiração pulmonar do conteúdo gástrico. O objetivo foi avaliar a área transversal do antro gástrico por meio de ultrassonografia. Método: Neste estudo prospectivo, 85 gestantes a termo agendadas foram submetidas à ultrassonografia do antro gástrico. Os desfechos foram a mensuração da área transversal do antro gástrico (desfecho principal), a estimativa do volume gástrico, a incidência de gestantes sob risco de aspiração pulmonar, a associação entre a área transversal do antro gástrico e características clínico-demográficas. A área transversal do antro gástrico e do volume gástrico foi comparada de acordo com o índice de massa corporal < 30 ou ≥ 30. Resultados: A mediana (IIQ) da área transversal do antro gástrico foi 4 cm2 (2,8-6,3), do volume gástrico estimado 49,8 mL (33,7-87,2) e do volume gástrico estimado em mL.kg-1 de 0,62 mL.kg-1 (0,39-0,95). O percentil 95 [intervalo de confiança (IC) 95%] da área transversal do antro gástrico e do volume gástrico estimado foi ≤ 10,3 cm2 (IC 95%: 7,6-15,6) e 1,42 mL.kg-1 (IC 95%: 1,20-2,64), respectivamente. A incidência de gestantes sob risco de aspiração pulmonar foi de 3,5% (IC: 3,5 (1,2-9,8). Houve correlação positiva entre a área transversal do antro gástrico e peso, p < 0,001 e índice de massa corporal p < 0,001. As pacientes com índice de massa corporal ≥ 30 apresentaram maior área transversal do antro gástrico, e do volume gástrico estimado, do que as com índice de massa corporal < 30, respectivamente p < 0,01 e p < 0,02. Conclusão: A mensuração da área transversal do antro gástrico de gestantes é factível e fácil. A área transversal do antro gástrico correlacionou-se positivamente com peso e índice de massa corporal. A estimativa do volume gástrico através da mensuração da área transversal do antro gástrico pode identificar pacientes sob risco de aspiração pulmonar. As pacientes obesas apresentaram área transversal do antro gástrico e volume gástrico estimado maior do que as não obesas.

Abstract Background and objectives: Pregnant women are considered patients at risk for pulmonary aspiration of gastric contents. The study aim was to evaluate the gastric antral cross-sectional area using ultrasound. Method: In this prospective study, 85 scheduled term pregnant women underwent gastric ultrasound. The outcomes were the measurement of the gastric antral cross-sectional area (main outcome), the estimated gastric volume, the incidence of pregnant women at risk for pulmonary aspiration, and the association between gastric antral cross-sectional area and clinical-demographic characteristics. Gastric antral cross-sectional area and gastric volume were compared according to body mass index <30 or ≥30. Results: The median (IIQ) for gastric antral cross-sectional area was 4 cm2 (2.8-6.3), for the estimated gastric volume it was 49.8 mL (33.7-87.2), and for the gastric volume estimated in mL.kg-1 it was 0.62 mL.kg-1 (0.39-0.95). The 95th percentile [95% confidence interval (CI)] of the gastric antral cross-sectional area and the estimated gastric volume were ≤10.3 cm2 (95% CI: 7.6-15.6) and 1.42 mL.kg-1 (95% CI: 1.20-2.64), respectively. The incidence of pregnant women at risk for pulmonary aspiration was 3.5% (CI: 3.5 (1.2-9.8)). There was a positive correlation between gastric antral cross-sectional area and weight, p < 0.001 and body mass index <0.001. Patients with a body mass index ≥30 had a gastric antral cross-sectional area and an estimated gastric volume greater than those with a body mass index <30, respectively, p < 0.01 and p < 0.02. Conclusion: Measuring the gastric antral cross-sectional area of pregnant women is feasible and easy. There was positive correlation between gastric antral cross-sectional area, body weight and body mass index. The estimation of gastric volume by measuring the gastric antral cross-sectional area can identify patients at risk for pulmonary aspiration. Obese patients had a gastric antral cross-sectional area and an estimated gastric volume greater than non-obese patients.