minimum appropriate dose of lidocaine with a fixed dose of sufentanil epinephrine used for spinal anesthesia in caesarian section

background caesarian section is a commonplace surgery in females for which spinal anesthesia is the preferred method. the local anesthetic medications used in the surgery are often associated with complications such as nausea, vomiting, dyspnea, hypotension, and bradycardia. in the present study, we decreased the dose of the anesthetic drug and added an opioid instead. objectives we tried to find an appropriate combination of medications required for optimal anesthesia with minimum complications. patients and methods one hundred twenty six candidates for c/s with first and second class asa aged 18-35 years were randomly divided into three groups. all patients received sufentanil (2.5 µg) and epinephrine (100 µg) doses but the lidocaine doses were respectively 50 mg, 60 mg and 75 mg in the groups 1, 2 and 3. complications including hypotension, bradycardia, dyspnea, nausea, vomiting, and anesthesia quality were recorded and statistically analyzed. results the level of anesthesia was significantly different between groups. by reducing the lidocaine dose, patients with anesthesia level under the nipple increased but the surgeon and the patient were satisfied with the results. nausea, vomiting, and dyspnea was degraded by decreasing the lidocaine dose especially in the 50 mg group. the need to use ephedrine was directly associated with the lidocaine. however, the need to use atropine was not significantly different between groups. pruritus was not significantly different as well. conclusions it seems that reducing the lidocaine dose, when combined with sufentanil, decreases most complications of spinal anesthesia such as hypotension, dyspnea, nausea, and vomiting while preserving anesthesia quality.