Prevention of Maternal Hypotension During Cesarean Section With Norepinephrine Infusion.

Neuraxial techniques are the anesthetic techniques of choice in contemporary obstetric anesthesia practice, with a definitive superiority as compared to general anesthesia, since, by their use, serious complications involving the airway can be avoided.Spinal anesthesia has become the favorable technique for both elective and emergency cesarean section due to a quick and predictable onset of action, however, it can be frequently complicated by hypotension, with incidence exceeding 80% occasionally. Recently, noradrenaline has been shown to be effective in maintaining blood pressure in obstetric patients. Another technique widely used to prevent hypotension is fluid administration. Current evidence suggests that the combination of fluid administration and vasoconstrictive medications should be the main strategy for prevention and management of hypotension accompanying neuraxial anesthesia procedures during cesarean section. Research is still underway in relation to the most appropriate timing for fluid administration, the most appropriate fluid volume as well as the type of fluid that should be administered. However, preloading of crystalloids seems to be inefficient as a sole strategy, while co-loading of colloids is more effective than co-loading of crystalloids for prevention of hypotension in the parturient. On the other hand, preloading and co-loading of colloids seem to be of equal effectiveness. Literature is rather scarce regarding the comparison of colloid preloading and crystalloid co-loading.

The aim of this randomized study will be to investigate the combination of a norepinephrine infusion and colloid preloading versus the combination of a norepinephrine infusion and crystalloid co-loading for the prevention of maternal hypotension during elective cesarean section.

Inclusion criteria

• adult parturients, American Society of Anesthesiologists (ASA) I-II,
• singleton gestation>37 weeks
• elective cesarean section

Exclusion criteria

• Body Mass Index (BMI) >40 kg/m2
• Body weight <50 kg
• Body weight>100 kg
• height<150 cm
• height>180 cm
• multiple gestation
• fetal abnormality
• fetal distress
• active labor
• cardiac disease
• pregnancy-induced hypertension
• thrombocytopenia
• coagulation abnormalities
• use of antihypertensive medication during pregnancy
• communication or language barriers
• lack of informed consent
• contraindication for regional anesthesia