Comparative Study between Single Dose Intrathecal Bupivacaine with Dexmedetomidine versus Bupivacaine with Fentanyl in Anesthesia for Cesarean Section

Abstract

Regional anesthesia has become more popular in cesarean deliveries because most of the parturients prefer being awake during the birth process. In addition, regional anesthesia may be a safer method than general. In spinal anesthesia, local anesthetics alone may not be enough for an effective postoperative analgesia and hemodynamic stability of the patient which is crucial during Cesarean section. So far many adjuncts have been used to augment the analgesia produced by intrathecal local anesthetics and to reduce their adverse effects. Dexmedetomidine is a highly selective alpha-2 agonist (α2-AR) that provides anxiolysis and cooperative sedation without respiratory depression. It decreases central nervous system (CNS) sympathetic outflow in a dose-dependent manner and has analgesic effects best described as opioid-sparing. There is increasing evidence that dexmedetomidine has organ protective effects against ischemic and hypoxic injury, including cardioprotection, neuroprotection, and renoprotection. Intrathecal Dexmedetomidine is found to haveantinociceptive action for both somatic and visceral pain. Experimental study on acute exposure of rats to dexmedetomidine at the anticipated delivery time recorded absence of any adverse effects on their perinatal morphology. The purpose of this study was to compare effects of single dose intrathecal Bupivacaine with Dexmedetomidine versus Bupivacaine with Fentanyl on labor outcome in spinal anesthesia for uncomplicated cesarean delivery. This study was conducted at Ain Shams University Hospital, obstetric department.Sixty patients were included in the study scheduled for elective cesarean delivery, and all received spinal anesthesia. First group Group D received intrathecal dexmedetomidine 5 µg with hyperbaric bupivacaine 10 mg in 2.5 ml. Dexmedetomidine. Second group Group F (control group) received intrathecal fentanyl 25 µg with hyperbaric bupivacaine 10 mg in 2.5 ml. After performing the spinal block, the vital signs were recorded every 5 minutes in the operation room and every 15 minutes in the Post Anesthesia Care Unit (PACU) until the patient discharged to the ward, after having achieved complete reversal of sensory and motor block. Sensory blockade was assessed using pinprick in the mid-axillary line. Recovery time for sensory blockade defined as two-dermatome regression of anesthesia from the maximum level. Motor block was assessed immediately after sensory block assessment using a Modified Bromage Scale (0 = no paralysis; 1 = unable to raise extended leg; 2 = unable to flex knee; 3 = unable to flex ankle). Motor block duration was the time for return to Modified Bromage Scale 1. The highest sensory block level and recovery time of both sensory and motor block were recorded. The Ramsay sedation score was used for sedation score (1 = anxious and agitated; 2 =cooperative and tranquil; 3 = drowsy but responsive to command; 4 = asleep but responsive to a glabellar tap; 5 = asleep with a sluggish response to tactile stimulation; and 6 = asleep and no response). The score was re-evaluated every 10 min for up to 120 min. Excessive sedation was defined as a score greater than 4/6. Hypotension was defined as a systolic blood pressure of less than 90 mmHg and if maintained, was treated with a bolus administration of 300 ml of Ringer’s solution over 5 min and 5 mg of intravenous ephedrine. Bradycardia was defined as a heart rate <50 beats/min, and if maintained was treated with 0.5 mg of intravenous atropine. Other side effects as nausea, vomiting and pruritus were recorded. The neonatal outcome for all neonates was assessed by APGAR scores at 1st and 5th min.