The Effect of Low-Dose Dexmedetomidine as an Adjuvant to Levobupivacaine in Patients Undergoing Vitreoretinal Surgery Under Sub-Tenon's Block Anesthesia.

BACKGROUND: This study evaluated the motor and sensory block durations and the postoperative analgesic effects of adding dexmedetomidine to levobupivacaine for sub-Tenon's block anesthesia in patients undergoing vitreoretinal surgery. Motor and sensory block durations were considered as a primary end point. METHODS: Sixty ASA physical status I to III patients subjected to vitreoretinal surgery under sub-Tenon's block anesthesia were randomly divided equally into 2 groups, depending on the local anesthesia solution used, to receive 4 mL of 0.75% levobupivacaine plus 15 IU hyaluronidase diluted with 1 mL normal saline (group L) or 4 mL of 0.75% levobupivacaine plus 15 IU hyaluronidase and 20 µg dexmedetomidine diluted with 1 mL normal saline (group LD). The total volume of the local anesthesia solution used was 5 mL. Motor block and sensory block durations were evaluated until the return of normal motor and sensory functions. The sedation level was assessed during the surgery period and 24 hours postoperatively, together with the degree of postoperative pain. The total diclofenac consumption (milligrams) and the number of patients (%) who required tramadol were recorded. The sleep quality of the first postoperative night was assessed using the Consensus Sleep Diary. RESULTS: Dexmedetomidine provided significantly longer motor block duration (371.90 ± 48.10 vs 264.13 ± 41.48 minutes, P = 0.001) and significantly longer sensory block duration (499.10 ± 51.76 vs 344.33 ± 45.46 minutes, P = 0.001) compared with levobupivacaine alone. Furthermore, the patients in the dexmedetomidine group achieved significantly (P < 0.0001) greater levels of sedation during the surgery period and for 12 hours postoperatively together with significantly (P < 0.0001) lower values of verbal numeric rating scale of pain between the periods from 4 to 12 hours postoperatively compared with the patients in the levobupivacaine group. There was significantly (P = 0.001) less diclofenac consumed (mg) in the dexmedetomidine group. The patients in the dexmedetomidine group reported significantly higher rates of good sleep quality on the first postoperative night (70%) compared with those in the levobupivacaine group (30%; P < 0.0001). CONCLUSIONS: For patients undergoing vitreoretinal surgery, adding 20 µg of dexmedetomidine to levobupivacaine for sub-Tenon's block anesthesia in vitreoretinal surgery extended the motor and sensory block durations and provided more effective postoperative analgesia with improvement in the sleep quality in the first postoperative night compared with levobupivacaine alone.

Single-injection percutaneous peribulbar anesthesia with a short needle as an alternative to the double-injection technique for cataract extraction.

BACKGROUND: We evaluated the efficacy of a single-injection technique for percutaneous peribulbar anesthesia with a short needle as an alternative to the double-injection technique for cataract extraction. METHODS: We included 200 patients who underwent elective cataract surgery randomized into 2 equal groups. They received either single-injection peribulbar anesthesia with a 16-mm needle or double-injection peribulbar anesthesia with a 25-mm needle. RESULTS: Both techniques provided comparable akinesia. A similar number of patients in each group required supplementary injection. The total volume of local anesthetic used was less in the single-injection group. There were no serious complications in the 2 groups. CONCLUSION: The single-injection technique for percutaneous peribulbar anesthesia with a short needle is a suitable alternative to the double-injection technique for cataract surgery.

The efficacy of 0.75% levobupivacaine versus 0.75% ropivacaine for peribulbar anesthesia in vitreoretinal surgery.

BACKGROUND: We evaluated the anesthetic efficacy and the postoperative analgesic effects of 0.75% levobupivacaine versus 0.75% ropivacaine for peribulbar anesthesia in patients undergoing primary vitreoretinal surgery. METHODS: We investigated 120 patients subjected to vitreoretinal surgery under peribulbar anesthesia. They were randomized into two equal groups according to the local anesthetic (LA) used, namely, 0.75% levobupivacaine or 0.75% ropivacaine, both with the addition of hyaluronidase. Nerve block was carried out by injection of 5-7 mL of the LA using single injection percutaneous peribulbar anesthesia with a short needle. RESULTS: When compared with 0.75% ropivacaine, 0.75% levobupivacaine provided more successful akinesia at 10 min after block (P=0.026), fewer supplementary injections (P=0.026), and less volume (mL) was used (P=0.031). Also, levobupivacaine provided significantly longer motor block duration (342±27 min versus 206±40 min, P=0.001) and significantly longer sensory block duration (513±24 min versus 394±11 min, P=0.001) when compared with ropivacaine. In the postoperative period, the patients in the levobupivacaine group achieved lower values of verbal numeric rating scale of pain compared with patients in the ropivacaine group among the period from 4 to 12 h. Also, there were significantly (P=0.001) lower diclofenac consumption (mg) and the percentage of patients who required tramadol rescue medication were significantly less (P=0.034) in the levobupivacaine group compared with the ropivacaine group. CONCLUSION: We are concluding that, at equipotent doses and concentrations, 0.75% levobupivacaine provides more effective peribulbar anesthesia and more effective postoperative analgesia for vitreoretinal surgery compared with 0.75% ropivacaine.

Single-injection percutaneous peribulbar anesthesia with a short needle versus sub-Tenon's anesthesia for cataract extraction.

PURPOSE: This study compared the efficacy of single-injection percutaneous peribulbar anesthesia (PBA) with a short needle with sub-Tenon's anesthesia (STA) to produce optimal operating conditions for cataract extraction in patients with complicated cataract. METHODS: Two hundred patients with complicated cataract were enrolled in this prospective, double-blinded, randomized study. Adequate akinesia was a surgical requisite for all cases included in the study because of the expected difficult surgery. The patients were divided into two equal groups to receive either peribulbar anesthesia (PBA) with a 16-mm needle or sub-Tenon's anesthesia. Surgical akinesia (as a primary end point), analgesia, incidence of complications, as well as patient and surgeon satisfaction (as secondary end points) were assessed. RESULTS: Both techniques provided similar analgesia during the operation and similar rates of incidence of chemosis with no serious complications; while the PBA group provided higher degree of akinesia 10 minutes after injection of the local anesthetic, a lower incidence of subconjunctival hemorrhage (SCH) and higher patient and surgeon satisfaction compared to the STA group. CONCLUSION: We concluded that when globe akinesia is necessary during surgery, the single-injection technique for percutaneous peribulbar anesthesia with a short needle proved to be more suitable than the STA in providing akinesia for cataract surgery. Also, this PBA technique demonstrated a lower incidence of SCH and was preferred to STA by the patients and surgeon.

Preanesthetic medication in children: A comparison of intranasal dexmedetomidine versus oral midazolam.

BACKGROUND: Relieving preoperative anxiety is an important concern for the pediatric anesthesiologist. Midazolam has become the most frequently used premedication in children. However, new drugs such as the α(2) -agonists have emerged as alternatives for premedication in pediatric anesthesia. METHODS: One hundred and twenty children scheduled for adenotonsillectomy were enrolled in this prospective, double-blind, randomized study. The children were divided into two equal groups to receive either intranasal dexmedetomidine 1 µg/kg (group D), or oral midazolam 0.5 mg/kg (group M) at approximately 60 and 30 mins, respectively, before induction of anesthesia. Preoperative sedative effects, anxiety level changes, and the ease of child-parent separation were assessed. Also, the recovery profile and postoperative analgesic properties were assessed. RESULTS: Children premedicated with intranasal dexmedetomidine achieved significantly lower sedation levels (P=0.042), lower anxiety levels (P=0.036), and easier child-parent separation (P=0.029) than children who received oral midazolam at the time of transferring the patients to the operating room. Postoperatively, the time to achieve an Aldrete score of 10 was similar in both the groups (P=0.067). Also, the number of children who required fentanyl as rescue analgesia medication was significantly less (P=0.027) in the dexmedetomidine group. CONCLUSION: Intranasal dexmedetomidine appears to be a better choice for preanesthetic medication than oral midazolam in our study. Dexmedetomidine was associated with lower sedation levels, lower anxiety levels, and easier child-parent separation at the time of transferring patients to the operating room than children who received oral midazolam. Moreover, intranasal dexmedetomidine has better analgesic property than oral midazolam with discharge time from postanesthetic care unit similar to oral midazolam.

Combined use of remifentanil and propofol to limit patient movement during retinal detachment surgery under local anesthesia.

BACKGROUND: One of the drawbacks of performing ophthalmic surgery under local anesthesia is patient movement, which might affect optimal surgical outcome. PURPOSE: The study aims to evaluate the efficacy of the combined use of propofol and remifentanil as a sedative technique in comparison with the use of propofol alone to limit patient discomfort and movement during local anesthesia for vitreo-retinal surgery lasting for more than two hours. MATERIALS AND METHODS: A total of 140 patients scheduled for vitreo-retinal surgery under local anesthesia, with an expected surgical time of more than two hours, were included in the study. Patients were divided randomly into two equal groups: group I where patients were given propofol and remifentanil by continuous infusion and group II where patients were given propofol alone by continuous infusion. RESULTS: The two groups were comparable with regard to age, weight, gender, ASA physical status and duration of surgery. There was a significant decrease in heart rate and mean arterial blood pressure (MABP) in each group 10 minutes after the start of sedation compared with pre-sedation data and continued all through the procedure. There was an insignificant difference between the two groups with regard to changes in heart rate and MABP all through surgical procedure. There was no significant difference between the two groups with regard to the incidence of complications except for an increased incidence of breakthrough pain and discomfort which necessitated the use of fentanyl as a rescue treatment in the propofol group P<0.001. There were no instances of movements with a major effect on the surgical field, which could have affected surgical outcome, in the two groups. The number of patients who did not move was significantly higher, 56 (80%), in group I compared with 38 (54.29%) in group II with P<0.001. The ophthalmologist satisfaction scale was significantly higher in group I (4.5±0.63) compared with group II (3.7±1.04) with P=0.0016. CONCLUSION: The combined use of propofol and remifentanil as a continuous infusion before performance of the block and during lengthy vitreo-retinal surgery was associated with a lower incidence of patient discomfort, breakthrough pain, and patient movement along with high degree of surgeons' satisfaction and hemodynamic stability.