Analgesic Efficacy of Two Adjuvants During Spinal Anaesthesia.

Comparison of the Analgesic Efficacy of Two Adjuvants to Hyperbaric Bupivacaine During Spinal Anaesthesia for Caesarean Section.

: Pain modulation is very important after operation, particularly for women who undergo caesarean section. A pain-free postoperative period is essential following a caesarean section so new mothers may care for and bond with their neonates. The consequences of the improper pain management which raise the healthcare costs and prolong the recovery process. Intrathecal adjuvants are often administered during this procedure to provide significant analgesia, but they may also have bothersome side effects. Intrathecal midazolam and magnesium sulfate produces effective postoperative analgesia with no significant side effects. Objectives: This prospective, randomized, double-blind study was designed to compare the analgesic efficacy and safety of intrathecal midazolam vs. Magnesium sulfate vs plain bupivacaine as an adjunct to bupivacaine in pregnancy patients scheduled for elective caesarean section.

The patients were randomly allocated using a computer-generated randomization list to one of three groups that contained 50 parturients each via www.randomization.com. Group C (control group): 10 mg hyperbaric bupivacaine 0.5% (2 ml) + 100γ morphine (1ml) + 2.5 γ sufentanil (0.5ml) + 1 ml physiological saline. Group Mg (magnesium sulfate group): 10 mg hyperbaric Bupivacaine 0.5% (2 ml) + 100γ Morphine (1ml) + 2.5 γ sufentanil (0.5ml) + 100 mg MgSO4 (1 ml). Group MDZ (midazolam group): 10 mg hyperbaric Bupivacaine 0.5% (2 ml) + 100γ Morphine (1ml) + 2.5 γ Sufentanil (0.5ml) + 2mg Midazolam (0.4 + 0.6cc physiological saline (1 ml)). The parturients as well as the anesthetist who evaluated the protocol did not know the nature of the adjuvant injected in spinal anesthesia. The presented syringe contained one of the two adjuvants or the physiological serum in the same volume and of the same appearance. It was prepared by an anesthesist who was not included in the analysis of the study and was presented anonymously to the anesthetist in charge of the patient. A postoperative monitoring (PO) was performed during the first 24 hours in the intensive care unit by the anesthesist who did not know the nature of the injected adjuvant. All patients were kept nil per os for six hours prior to surgery.

Bupivacaine,, Anesthetics, Adjuvants, Analgesics, Peripheral system, Central Nervous, sensory system, Agents, Physiological effects of drugs, opioid, Pain, Postoperative, Signs and Symptoms

Spinal injection of 10 mg hyperbaric bupivacaine 0.5% (2 ml) + 100γ morphine (1ml) + 2.5 γ sufentanil (0.5ml) + 1 ml physiological saline.

Spinal injection of 10 mg hyperbaric Bupivacaine 0.5% (2 ml) + 100γ Morphine (1ml) + 2.5 γ sufentanil (0.5ml) + 100 mg MgSO4 (1 ml).

Spinal injection of 10 mg hyperbaric Bupivacaine 0.5% (2 ml) + 100γ Morphine (1ml) + 2.5 γ Sufentanil (0.5ml) + 2mg Midazolam (0.4 + 0.6cc physiological saline (1 ml)).

Postoperatively, the patients were observed for the duration of analgesia using the Visual Analog Scale for Pain (VAS Pain), from 0 - 10 (with 0 being no pain and 10 being the most severe pain imaginable) at H2, H4, H6, H10, H12, H24 at rest and coughing or mobilization until supplementary analgesia was required. The duration of effective analgesia was defined as the time interval between administration of the IT drug to the time of first analgesic request or a VAS ≥ 4. Rescue analgesics were given in the form of a paracetamol injection (1g IV) as well as nefopam (20 mg IV) injection once the VAS was recorded as 4 or more.

. The assessments of the sensory and motor blocks were taken at the end of each minute until the maximum level of block (T4) was achieved and were assessed using a short, beveled 22-gauge needle and tested at the mid_clavicular line on the chest, trunk, and legs on either side. The duration of the sensory block was defined as the time for regression of the sensory block from the maximum block height to the L-1 dermatome as evaluated by a pinprick.

The motor block was assessed using the Modified Bromage score (1:Complete block (unable to move feet or knees); 2: Almost complete block (able to move feet only); 3: Partial block (just able to move knees); 4: Detectable weakness of hip flexion while supine (full flexion of knees); 5: No detectable weakness of hip flexion while supine; 6: Able to perform partial knee bend).

Hypotension was defined as a more than 20% decrease in the systolic blood pressure from the baseline. It was treated with IV fluids and an additional bolus of intravenous (IV) ephedrine (0.1 mg/kg) was repeated at the discretion of the attending anesthesiologist at incremental doses

Bradycardia was defined as a decrease in the pulse rate to less than 45 beats per minutes and was treated with an IV injection of 0.5mg atropine sulfate.

The sedation scores were recorded using the observer's assessment of the Ramsay scale (Ramsay 1: Anxious, agitated, restless; Ramsay 2: Cooperative, oriented, tranquil; Ramsay 3: Responsive to commands only; Ramsay 4: Brisk response to light glabellar tap or loud auditory stimulus; Ramsay 5: Sluggish response to light glabellar tap or loud auditory stimulus; Ramsay 6: No response to light glabellar tap or loud auditory stimulus).

Maternal satisfaction concerning the anesthetic technique was evaluated by the following score:• Excellent = comfort and satisfactory analgesia• Good = average comfort and acceptable analgesia • Poor = significant and lasting discomfort.

Inclusion Criteria: a mono fetal pregnancy, term> 35 week, planned caesarean section under spinal anesthesia, six-hour fasting, and the American Society of Anesthesiologists (ASA) physical status I or II. Exclusion Criteria: contraindication for intrathecal injection, known allergies to midazolam, other benzodiazepines, magnesium sulfate, caesarean section in extreme urgency, preeclamptic parturient, foetal death in utero, premature delivery (<32SA), anomaly of the placentation, any significant cardiovascular or hepatorenal diseases, a history of seizures or convulsive neurological disease, an altered coagulation profile. Exclusion criteria: failure of spinal anesthesia, conversion into general anesthesia, anesthetic or surgical perioperative incident requiring resuscitation, traumatic puncture, occurrence of serious complication of spinal anesthesia, loss of blindness or randomization of patients.

Zakeri H, Pouralborz Y, Askari A, Parkhah M, Hosseinipour A. The adjunctive midazolam or magnesium sulfate to intrathecal bupivacaine analgesic effect in caesarean section: a randomized controlled trial. Biomedical Research. 2017; 28: 3783-3787.