Efficacy of Dexmedetomidine Infusion Without Loading Dose as a Potent Hypotensive Agent in Lumbar Fixation Surgery

Background: Dexmedetomidine on the basis of the previous literature can be considered a safe agent for controlled hypotension through its central and peripheral sympatholytic action. Its easy administration and absence of fatal side effect make it a near-ideal hypotensive agent. This study was intended to evaluate the efficacy of dexmedetomidine infusion “without loading dose” as an effective hypotensive agent in lumbar fixation surgery. Methods: In a double-blind study, a total of 60 patients aged 18-65 years, of both genders, belonging to the American Society of Anesthesiologist (ASA) class I - II scheduled for elective lumbar spine instrumentation were included and divided into: Control group (Group C) who received placebo and Dexmedetomidine group (Group D) who received Intravenous (IV) dexmedetomidine. The patients were compared primarily for intraoperative hemodynamics. Results: The study results showed that dexmedetomidine had successfully maintained target mean blood pressure of 65-70 mmHg and only 2 patients out of 30 required rescue therapy (both of propofol and NG). Also, dexmedetomidine had maintained heart rate stability than the control group from the 15th minute after positioning till the end of surgery (P-value < 0.001). Intraoperative fentanyl consumption was significantly low in Dexmedetomidine group 75 ± 25.43 µg versus 169.64 ± 34.26 µg in Control group (P-value < 0.001). Finally, more post-operative sedation was noticed during the 1st postoperative hour in dexmedetomidine group when compared to the control group (P-value < 0.001). Conclusion: Dexmedetomidine infusion without loading dose could be an effective and safe agent in achieving controlled hypotension in adults undergoing elective lumbar spine instrumentation surgery with limited side effects together with intraoperative opioid-sparing effect.

Corneal sterile infiltration induced by topical use of ocular hypotensive agent

Purpose: To report two cases with corneal sterile infiltration presumably due to topical ocular hypotensive agent. Method: Case report. Results: Case 1: A 65-year-old man presented with corneal opacity and neovascularization in his left eye. A diagnosis of glaucoma was made 2 years previously, and anti-glaucoma agents were prescribed (brimonidine tartrate, ripasudil hydrochloride hydrate, and brinzolamide) for both eyes. Case 2: A 75-year-old woman noticed corneal opacity in the left eye. A diagnosis of glaucoma was made 35 years previously, and anti-glaucoma agents were prescribed (brimonidine tartrate, 1% dorzolamide, and bimatoprost) for both eyes. In both cases, ocular examination revealed follicular conjunctivitis and blepharitis in both eyes, and corneal sterile infiltration with neovascularization in the left eyes. The three topical drugs were discontinued and replaced with 0.1% fluorometholone. Both the blepharitis and corneal sterile infiltration improved thereafter, although corneal opacity remained across the stromal layer. Conclusion: We encountered two cases of corneal and conjunctival complications that were suspected as side effects after brimonidine eye drop use. Special care should be taken to observe the condition of ocular surface when topical brimonidine is administered.