Effect of Intravenous Dexmedetomidine on Spinal Anesthesia

Neuraxial Analgesia for Scoliosis Correction: A Case Series in a Specialised Children's Centre

BACKGROUND

Surgical correction of spinal deformities in children presents a challenge to the anaesthetist due to the extensive nature of the surgery, the co-morbidities of the patients and the constraints on aesthetic techniques of intraoperative neurophysiological monitoring of the spinal cord. Patients undergoing scoliosis surgery are considered to suffer severe pain, which may lead to a negative impact on patient psychology and physical well-being. By using effective postoperative pain regimens to enhance recovery after surgery, pain can be significantly reduced, leading to patient satisfaction, facilitating early mobilisation, promoting oral intake, lowering postoperative pain and shortening the length of hospital stay. Thus, the primary objectives of this study were to assess the postoperative pain management and first rescue analgesic medications, by using preservative-free morphine 50 mcg/kg and dexmedetomidine 4 mcg along with normal saline 0.5 ml kg caudally, as well as to look for the secondary objectives side effects, including respiratory depression, nausea, vomiting and pruritis, timing of postoperative ambulation and length of hospital stay.  Methods: In this study, we retrospectively included children under 14 years of age and above three years who underwent scoliosis surgery under a caudal epidural-general anaesthesia using caudal morphine and the dexmedetomidine technique in the period from January to May 2023 at the National Guard Health Affairs Hospital (NGHA), Riyadh. We collected the data of seven cases using the electronic chart system of the Best Care database to extract the specific cases that meet the inclusion criteria for the study, which are idiopathic scoliosis patients, aged 3-14 years, and primary correction procedures.  Results: The pain-free duration was between seven hours and 48 hours (about two days). There were four female cases (57.14%), and three cases were male (42.85%). The patients' American Society of Anesthesiologists (ASA) status were II to III. In all the cases, there was no documentation of any episodes of postoperative nausea and vomiting (PONV), respiratory distress or pruritus, except for one case where the patient had an episode of PONV.  Conclusion: In this study, our aim was to present our experience with dexmedetomidine as an efficient medication when coadministered with morphine to be used in the operating room. We found a high level of reliability in prolonging analgesia time and delaying the usage of rescue medication. We encourage more studies on caudal dexmedetomidine for patients undergoing scoliosis surgery.

The Effects of Premedication With Three Different Doses of Intravenous Dexmedetomidine on Spinal Anesthesia: A Randomized Comparative Study

BACKGROUND

Intravenous dexmedetomidine is one of the commonly preferred techniques for sedation during any regional procedure. However, only a very few studies compared the impact of different bolus doses during spinal anesthesia, and none for our geographical area.

MATERIALS AND METHODS

A total of 60 patients were allocated into either of the three groups (group I, II, III) to receive intravenous dexmedetomidine 0.5, 0.75, and 1 mcg/kg, respectively. The primary outcome was to compare the duration of sensory and motor blockade and the secondary outcomes were the level of sedation, hemodynamic stability, duration of analgesia, and the side effects, if any.

RESULTS

Two-dermatome regression time and the duration of motor block were significantly higher in groups II and III when compared to group I. However, the difference in duration of analgesia, Ramsay sedation scores, bradycardia, and hypotension was statistically insignificant between the groups.

CONCLUSION

Intravenous dexmedetomidine in doses of 0.75 and 1 mcg/kg significantly prolongs the two-dermatome regression time and duration of the motor block when compared to 0.5 mcg/kg dose. Hence, it is better to titrate the dose between 0.75 and 1 mcg/kg, as the administration of bolus intravenous Dex in doses ranging between 0.75 and 1 mcg/kg appears to provide adequate intraoperative block characteristics while maintaining hemodynamic stability without any significant respiratory depression or other adverse effects.