on arrival to the operating room, the demographic and baseline data will be collected,
which include sections about age, height, weight, primigravida or multigravida, cervical
dilation at the time of performing labor analgesia, fetus presentation, presence of
rupture of membrane, baseline pain scores will be assessed using a 10-cm VAS (0 = no pain
and 10 = worst imaginable pain) before SSSA. Intravenous access will be achieved in all
patients loading will be undertaken using 500 ml Ringer's solution, baseline values of
pulse rate (PR), respiratory rate (RR), hemoglobin oxygen saturation (SpO2), and arterial
blood pressure (ABP) will be recorded. SSSA will be performed with the parturient in the
sitting position under complete aseptic precautions at the L3-L4 level using a 25-gauge
spinal needles. The correct positioning of the needle tip in the intrathecal space will
be confirmed by the observation of a free flow of cerebrospinal fluid, and then the
prefilled study drug will be injected intrathecally which is 2.5 mg bupivacaine plus 25
mic fentanyl or 5 mic dexmedetomidine or 0.5 ml saline according to different groups.
parturient will then turn to the supine position, and a wedge will be placed under the
right buttocks to prevent aortocaval compression. VAS will be evaluated every 5 min for
the first 30 min, followed by every 20 min for 3 hours then every 30 min for next 3
hours. If VAS 8 or more the instigators will give the patient 50 mg intramuscular
pethidine and the patient will be excluded.
Maternal blood pressure, heart rate, respiratory rate, and oxygen saturation will be
measured and recorded noninvasively every 5 min for the first half hour, followed by
every 20 min for 3 hours, then every 1 h for next 3 hours. the investigators will give 5
mg ephedrine if there is hypotension ( decrease in ABP more than 25% of the baseline ABP)
and .5 mg atropine if there is bradycardia (HR less than 50 beats per minute). Side
effects such as hypotension, nausea, vomiting, bradycardia, shivering, pruritus, and
tachycardia will be recorded. The first- and fifth-minute Apgar scores will also be
recorded. The onset, duration of analgesia, and obstetric and neonatal outcomes will be
compared. Maternal satisfaction questionnaire will be done after delivery to assess
maternal satisfaction.