Spinal Anesthesia in Caesarean Section

This is a prospective, monocentric, not for-profit, observational study, with historical control group, whose primary objective is the monitoring of changes in the hemodynamic condition, intended as continuous pressure measurements by means of a non-invasive system (EV1000® platform + Clearsight® system - Edwards Lifesciences), of a group of 125 pregnant women who have to undergo spinal anesthesia with Levobupivacaine for elective cesarean section at the "G. Rodolico" Presidium of Azienda Ospedaliero Universitaria "Policlinco-Vittorio Emanuele" of Catania, and to compare them with those detected, with the same non-invasive system, in an historical cohort of 125 patients who underwent spinal anesthesia with Bupivacaine for an elective caesarean section in the period between April 2017 and April 2018.

The study will have an expected duration of one year from the time of its approval.

In the levobupivacaine group, during the preoperative anesthesiological examination, carried out approximately two weeks before the scheduled date of the surgical intervention, informed consent will be acquired and the eligible patients will be enrolled. On this occasion, an ASA class will be assigned and the following data will be collected:

• personal and general data:
• date of birth and age
• current weight
• weight before pregnancy
• height
• information concerning:
• any previous or concomitant diseases affecting the nervous, respiratory, cardiovascular system
• any previous or concomitant disease interesting: gastrointestinal system, hemolymphatic system, thyroid, pancreas, kidneys, liver, adrenal glands
• any immunodeficiencies
• any coagulopathies
• spinal deformities
• previous surgeries
• previous allergic events following the administration of drugs
• seasonal allergies
• previous pregnancies and their characteristics
• possible hypertension during the last quarter
• conditions that represent contraindications for spinal anesthesia. Upon arrival in the operating room, the Clearsight® non-invasive hemodynamic monitoring system will be placed at the fingers of the parturient and the usual intraoperative monitoring (ECG, non-invasive blood pressure, oxygen saturation) will be applied. The continuous recording of the following hemodynamic parameters, which will last for the whole duration of the intervention, will then begin through the EV1000® platform (Edwards Lifesciences): Cardiac Output (CO); Cardiac Index (CI); Stroke Volume (SV); Stroke Volume Index (SVI); Stroke Volume Variation (SVV); Pulse Rate Variation (PRV); Systemic Vascular Resistance (SVR); Systemic Vascular Resistance Index (SVRI); Central Venous Oxygen Saturation (ScvO2); Pulse rate (PR); Systolic Pressure (SYS); Diastolic Pressure (DIA); Mean Arterial Pressure (MAP); Central Venous Pressure (CVP).These measurements will be made every twenty seconds.

Once the monitoring system has been applied, the patients will be placed in position and spinal anesthesia will be performed with Levobupivacaine 12 mg 0.5% and Fentanyl 25γ. Once the anesthetic is injected, patients will be subjected to dislocation of the uterus and placed in left lateral tilt. Once the sensory and motor block has been obtained, the surgery will begin. In the event of adverse reactions to the drug, therapeutic measures that are part of the usual clinical practice will be used.

Any episodes of hypotension during the operation will be treated by administration of 5 mg etilefrine in bolus and/or IV fluids; any episodes of bradycardia will be treated by administration of IV atropine 0.01 mg/kg.

Sensory block will be evaluated by objective examination: the investigators will evaluate the tactile discrimination ability of a blunt tip in contact with the patient's back, thus determining the level of anesthesia reached and the time in which it occurs. The measurements of this parameter will be carried out every fifteen minutes, during the first half hour, and then at thirty and sixty minutes until the restitutio of the physiological condition of the patient.

The motor block will be evaluated by Bromage score, ie by observing the residual motor capacity of the patient's lower limbs. The measurements of this parameter will be carried out every fifteen minutes, during the first half hour, and then at thirty and sixty minutes until the restitutio of the physiological condition of the patient.

For calculating the Aldrete's score, the following parameters will be assessed: respiration and consciousness through objective examination, systolic blood pressure using the classic intraoperative monitoring system and pulse oximetry oxygenation. The measurements of this score will be carried out every fifteen minutes during the first half hour, and then at thirty and sixty minutes until the restitutio of the physiological condition of the patient.

Patient data from the historical cohort will be collected by reviewing the clinical documentation related to the individual case.

Once collected, the data will be subjected to statistical and comparative processing in order to highlight statistically relevant differences concerning the effects mediated by the two anesthetics on the pregnant patient who undergoes elective cesarean section.

The data obtained will be analyzed using the SPSS software (Statistical Package for Social Sciences), version 21.0 for Windows (SPSS Inc., Chicago, Illinois, USA). Differences with p≤ 0.05 will be considered significant.

The descriptive analysis will be performed using frequencies, percentages and frequency tables for qualitative variables. For the normally distributed quantitative variables the mean and standard deviation will be used, while for those not normally distributed the median and the interquartile range (IQR) will be used. For the comparison between the two groups will be used the Chi-square test with Yates correction or Fisher exact test for qualitative variables and the Mann-Whitney U test for quantitative variables.

Multivariate analysis will be performed using logistic regression models and the ORs (odds ratios) will be reported together with the corresponding 95% confidence intervals.