Effect of different doses of compound sodium chloride injection combined with norepinephrine on prevention of hypotension after lumbar anesthesia in patients undergoing caesarean section / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of different doses of compound sodium chloride injection combined with norepinephrine on prevention of hypotension after lumbar anesthesia in the patients undergoing caesarean section.Methods:A total of 150 patients with a singleton fetus, aged 18-45 yr, at ≥37 weeks of gestation, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, with height ≥150 cm, weighing ≤100 kg, with body mass index < 40 kg/m 2, scheduled for elective caesarean section under lumbar anesthesia, were divided into 3 groups ( n=50 each) by the random number table method: compound sodium chloride injection 4, 8 and 12 ml·kg -1·h -1 groups (group A, group B, group C). Compound sodium chloride injection 4 ml/kg was intravenously injected for liquid preload before lumbar anesthesia, and 0.5% hyperbaric bupivacaine 12.5 mg was injected to the subarachnoid space for lumbar anesthesia. Norepinephrine was intravenously injected at a dose of 6 μg immediately after intrathecal injection, followed by an infusion of 0.05 μg·kg -1·min -1, and infusion was stopped at 5 min after delivery. Compound sodium chloride injection was intravenously infused simultaneously at a rate of 4, 8 and 12 ml·kg -1·h -1 in A, B and C groups, respectively. The maximum diameter of inferior vena cava (IVCmax) and the minimum diameter of inferior vena cava (IVCmin) were measured by ultrasound, and inferior vena cava collapse index (IVC-CI) was calculated at 1 min before fluid preload (T 1), immediately after fluid preload (T 2), at 5 min after anesthesia (T 3), at 5 min after fetal delivery (T 4) and immediately before leaving the operating room (T 5). The incidence of intraoperative adverse events (hypotension, severe hypotension, bradycardia, hypertension, nausea, and vomiting) and neonatal outcomes (umbilical artery blood gas index and Apgar score at 1 and 5 min after birth) were recorded. Results:Compared with group A, IVCmin was significantly increased and IVC-CI was decreased at T 5 in group B, and IVCmin and IVCmax were significantly increased and IVC-CI was decreased at T 5 in group C ( P<0.05). There was no significant difference in IVCmax, IVCmin and IVC-CI at each time point between group B and group C ( P>0.05). There was no significant difference in the incidence of hypotension, severe hypotension, bradycardia, hypertension, nausea and vomiting among the three groups ( P>0.05). There was no significant difference in the results of blood gas analysis of the umbilical artery and Apgar score at each time point after birth among the three groups ( P>0.05). Conclusions:Compound sodium chloride injection 4, 8 and 12 ml·kg -1·h -1 combined with norepinephrine can effectively prevent the occurrence of hypotension after lumbar anesthesia in the patients undergoing caesarean section without increasing maternal and infant adverse events, and the effect of 8 and 12 ml·kg -1·h -1 for volume supplementation is better than that of 4 ml·kg -1·h -1.