Sevoflurane and Success of External Cephalic Version (ECV)
Sevoflurane and Success of External Cephalic Version (ECV)
External cephalic version (ECV) is noninvasive procedure aiming to turn the fetus to cephalic
 presentation, thereby enabling vaginal delivery and avoiding unnecessary cesarean delivery.
 The American College of Obstetricians and Gynecologists (ACOG) suggested that all women near
 term with breech presentation should be offered a version (9). Its success rate depends on
 the experience of obstetrician in addition to maternal factors. Several interventions have
 been tried to increase the success rate of ECV, including but not limited to tocolytics and
 neuraxial anesthesia. Although parenteral β stimulants and spinal anesthesia proved to be
 effective for increasing the success rate ECV, their success rates are still not high (10,
 11) Sevoflurane's pleasant odor, lack of pungency, and potent bronchodilating characteristics
 make sevoflurane administration via the facemask for either sedation or induction of
 anesthesia is suitable. Sevoflurane has sedative and uterine relaxation effects all together
 would facilitate ECV and consequently would increase its success rate. To the best our
 knowledge sevoflurane has never been studied for ECV. Up to 1% concentration of sevoflurane
 has been used for labor analgesia without excessive sedation (8). Therefore, the
 investigators aim at comparing the success rate of ECV at 36-40 weeks of gestation under 1%
 of sevoflurane with a control group (received no anesthetic or other obstetric
 interventions). Other outcomes such as pain score and maternal and fetal complications will
 also be evaluated.
Pre- procedure all parturients will be asked to be fasting for 8 hours for solid and 2 hours
 for clear liquids. Before ECV (as routinely done in ECV procedure), a cardiotocogram (CTG)
 and obstetric ultrasound will be done to confirm the fetal wellbeing and fetal position prior
 to procedure. The mother and fetus were monitored for at least 30 min before attempting ECV.
 The procedure will be performed by one of two experienced obstetricians. Fetal heart rate
 will be recorded throughout the procedure.

 In the operating room, standard monitoring will be placed, as well as intravenous line will
 be established on an upper limb. Baseline measures of BP, HR, O2 Saturation will be taken
 before proceeding to inhalation sedation, including 3 baseline blood pressure readings to
 determine baseline values. A circle system, including antibacterial filter and scavenging
 system is connected to the anesthesia machine (Datex-Ohmeda).

 If the parturient is assigned to the control (nonintervention) group, the participants will
 not receive any medications neither tocolytics nor analgesics as we do routinely in our
 hospital. However, these participants will be monitored throughout the procedure for vital
 signs and for pains scores as in the intervention group (see below).

 In the intervention group, each participant started by preoxygenation of 100% oxygen for
 3minutes. Then, parturients breath 1% of sevoflurane in mixture of oxygen and air (FIO2 0.5)
 by tight face mask with a gas flow of 6 L/min. Values of inspired (FI) and end-tidal (FET)
 concentrations of sevoflurane, oxygen and respiratory rate (RR) measured by end-tidal carbon
 dioxide (EtC02) were monitored continuously and recorded at 30 seconds intervals by a gas
 analyzer.

 Thirty seconds after stating inhalation sedation, the obstetrician will be asked to start the
 procedure. HR, FI and FET concentration of sevoflurane, Sp02 and EtC02 will be recorded at 30
 seconds intervals during ECV. Non-invasive BP will be recorded every one minute. The duration
 of ECV in addition to the level of difficulty estimated by obstetrician will be recorded. In
 noninterventional (control) group, the patients will not receive any medication or anesthetic
 intervention however their vital signs including Sp02, BP and HR will be monitored throughout
 the procedure at the same interval used for the intervention group, their pain score will be
 measured as in the intervention group (see below).

 A hypotensive episode will be defined as 2 consecutive systolic BP (SBP) measurements less
 than 20% below the baseline value. The treatment of hypotension consists of Phenylephrine 1
 mcg/kg IV bolus will be administered if HR > 60 bpm or Ephedrine 5 mg IV bolus if HR is < 60
 bpm. If only the HR is < 55 bpm, but SBP is normal, Glycopyrrolate 0.2 mg IV bolus will be
 administered.

 ECV considered successful when a cephalic presentation, confirmed by ultrasound scan,
 achieved. Pain intensity measured by VAS will be recorded at the end of procedure and 10
 minutes after. In addition, the women's level of satisfaction with the procedure will be
 assessed using another numerical rating scale (0 = completely dissatisfied, 10 = completely
 satisfied) 10 min after the end of attempted ECV.

 The intervention will be stopped if the woman reported severe pain, if the version could not
 be achieved readily, or if prolonged fetal bradycardia, uterine bleeding or placental
 abruption occurred.

 Parturient will be kept in the Post Anesthesia Care Unit (PACU) for 45minutes. CTG will be
 monitored during PACU stay. Maternal oxygen saturation will be measured continuously using
 pulse oximetry, episodes of hypoxia (Sp02 ≤95%) and need for oxygen therapy will be recorded.
 Blood pressure will be measured every 5 min; hypotension was defined as a fall in blood
 pressure of >20% from baseline and will be treated as perioperative period (see above).
 Isolated bradycardia with HR < 50 bpm will be treated by glycopyrrolate 0.2mg IV bolus.
 Nausea and vomiting will be documented as adverse effects, regardless of when they occurred,
 and were treated with intravenous ondansetron 4 mg. Other maternal side effects including
 drowsiness and dizziness were also documented.

 Data Collection Pre-procedure and intra-procedure and post-procedure data will be collected
 by an anesthesia resident, or an anesthesiologist Not involved in the procedure.

 -  Pre-procedure data:

 -  Age, weight, height, gestation, gravida, parity

 -  Estimated fetal weight

 -  Number of prior cesarean deliveries

 -  Reason for the ECV

 -  Intra-procedure data:

 -  HR, Sp02, EtC02 for RR, FI and FET concentration of sevoflurane will be recorder
 every 30 seconds

 -  BP every one minute

 -  Episode of tachycardia

 -  Episode of hypotension

 -  Episode of desaturation (Sp02 ≤95%)

 -  Nausea or vomiting

 -  Use of ondansetron

 -  Pain intensity measured by VAS

 -  Transient fetal bradycardia

 -  Emergency Cesarean delivery

 -  Post-procedure data:

 -  HR, RR, Sp02, BP will be recorded every 5 minutes

 -  Pain score measured by VAS 10 minutes after ECV

 -  Episodes of desaturation

 -  Episodes of hypotension

 -  Nausea or vomiting

 -  Drowsiness

 -  Dizziness

 -  Fetal bradycardia

 -  Maternal satisfaction by using numerical rating scale 0-10 (see above) 10 min after
 the end of attempted ECV

 -  Mode of delivery after successful and failed ECV will be recorded by reviewing the
 electronic medical records

 Randomization:

 - Randomization will be achieved by a statistician using an online random number generator

 Sample Size Estimation A sample size of 40 parturients (20 per group) would give 80% power to
 detect a difference of 0.2 in the change in successful ECV rate.

 Assuming the use of sevoflurane will have 65% success rate and confidence interval 95% with
 5% margin of error and total number of cases per year in our center is 45 patients. The
 average success rate of ECV in patients who either did not receive any intervention or just
 receive intravenous analgesia is 43.1% (10). So, we are aiming to increase the success rate
 of ECV by using Sevoflurane to be more than or equal to 65%.

 The sample size calculation will be 40 cases. The sample size was calculated by the help of
 this website (http://www.raosoft.com/samplesize.html).

 Statistical Analysis

 This prospective randomized controlled study will compare the difference in success rate of
 ECV when a subject receives a sevoflurane or not. Other covariable like pain scores and
 adverse effects will also be recorded. Data will be stored in an excel database and analyzed
 with SPSS statistical software.

 Demographic data and intraoperative and PACU continuous and categorical data will be analyzed
 by Student t-test, ANOVA for repeated measures, or Chi-Squared test, accordingly.

 A P-value < 0.05 will be considered statistically significant.
Inclusion Criteria:

 -  Patients > 18 years old

 -  ASA status I or II (healthy women or patient with mild well-controlled systemic
 disease)

 -  Elective ECV

 -  36 to 40 weeks of gestation

 Exclusion Criteria:

 -  Multifetal gestation

 -  Morbid obesity (BMI > 40 at first prenatal medical visit)

 -  Oligohydramnios or polyhydramnios (AFI <5 cm or > 23 cm)

 -  Fetal weight >4200g

 -  Active labor

 -  Uterine tumors or anomalies

 -  Abnormal placentation such as Placenta accreta/Previa

 -  Placental abruption

 -  Intrauterine fetal death

 -  Known allergy to sevoflurane

 -  History of malignant hyperthermia

 -  Administration of any tocolytics before or during ECV