Ketamine versus magnesium sulphate as an adjuvant to local anesthetics in the peribulbar block for posterior segment surgeries: A randomized controlled study

To evaluate the effects of ketamine and magnesium sulphate as adjuvants to local anesthetic mixtures on the onset, duration, and quality of peribulbar block in patients scheduled for posterior segment surgeries.

Parallel group, randomized, controlled, clinical trial with 1:1:1 allocation ratio.

Research Institute of Ophthalmology, Giza, Egypt.

We included adult (45-65 years-old), male and female patients, scheduled for posterior segment operations who were American Society of Anesthesiologists physical status I or II and had an axial length < 25 mm. We excluded patients with coagulation abnormalities, impaired mental status, allergy to any of the study medications, and those having problems that interfere with surgeon patient communication and cooperation as deafness. In addition, patients with severe cardiac disease, chronic obstructive lung disease, history of sleep apnea, advanced liver or kidney disease, and history of chronic use of sedatives, narcotics, alcohol or drug abuse were excluded.

The current trial has three groups. The first was given peribulbar anesthesia with a local anesthetic mixture composed of lidocaine 2% (4.5 ml), plain bupivacaine 0.5% (4.5 ml), 1 ml of normal saline, and hyaluronidase (13.5 IU per ml of the mixture). The second received the same anesthetic mixture plus 25 mg of ketamine added to 1 ml of normal saline. The third received the same anesthetic mixture plus 50 mg of magnesium sulphate added to 1 ml of normal saline.

Outcome variables included the onset and duration of globe akinesia, duration of lid akinesia, onset of sensory block, time to start surgery, total analgesic time, intraocular pressure, and patient and surgeon satisfaction.

We used the sealed, opaque sequentially numbered envelopes method for randomization and allocation concealment of patients included in this trial. We used 126 identical, opaque, letter-sized envelopes lined with sheets of household aluminum cooking foil to ensure opacity. We prepared 126 envelope-sized sheets of white paper and 126 envelope-sized sheets of single sided carbon paper. We wrote “Treatment A” on 42 paper sheets, “Treatment B” on another 42 sheets, and “Treatment C” on the last 42 sheets. To prepare 42 “Treatment A” envelops, we selected one envelope-sized sheet of Treatment A and placed one sheet of carbon paper on top of the Treatment A allocation paper with the carbon side facing the paper, then we inserted both into a blank envelope with the carbon paper closest to the front of the envelope. Finally, we sealed the envelop and signed across the seal. We completed all the 42 “Treatment A” envelops the same way. We prepared 42 “Treatment B” as well as 42 “Treatment C” envelops similar to “Treatment A” envelops. The three sets of envelops were combined and shuffled thoroughly. Using a pen, we marked a number on the front of each envelope sequentially from 1 to 126 so the carbon paper inside the envelope transfer this number to the allocation paper inside. Finally, we placed these envelopes into a large plastic container, in numerical order, ready for use.

The study participants and care providers (carrying out the peribulbar block and assessing the participants' outcomes) were blinded to the type of intervention.

Ketamine and magnesium sulphate in peribulbar block for posterior segment surgeries IPD set (all collected deidentified IPD).

Beginning 6 months and ending 24 months following article publication.

Researchers from academic institutions whose proposal for the use of data has been approved by an independent review committee identified for this purpose.

For IPD meta-analyses.

From the principal investigator (A proposal for the use of data to be submitted to the principal investigator).

proposal for the use of data to be submitted to the principal investigator, then evaluated by an independent review committee identified for this purpose.