The Sedative Effects of Dexmedetomidine VS Propofol During Peribulbar Anesthesia in Patients Undergoing Vitrectomy Surgery

In ocular surgery, local anesthesia or regional anesthesia is generally preferred over general anesthesia because of quicker patient rehabilitation and the avoidance of possible complications from general anesthesia. However, even with these anesthesia techniques, pain, fear and anxiety are major predictors of lower patient satisfaction.

Vitrectomy surgery is one of the most common outpatient ophthalmic surgeries. It can be performed with peribulbar anesthesia and intravenous (IV) sedation support, allowing the procedure to be completed in most patients without the need for general anesthesia. Vitrectomy surgery is a painful and lengthy procedure; therefore, sedation is applied to reduce patient agitation, ensuring both surgical comfort and hemodynamic stability. However, various complications can arise during the perioperative period depending on the sedation agent used.

Intravenous sedation is frequently used during ophthalmic regional anesthesia. There is no 'ideal' drug for sedation or analgesia. Various drugs either alone or in combination have been used with different methods of administration. The preferred sedative agent for ophthalmic surgeries performed under local anesthesia should have rapid onset but a short duration of action to ensure rapid recovery. It should be non-accumulating, non-toxic and have a favorable therapeutic index with minimal side effects. Unfortunately no drug is presently available that fulfils all these criteria. The available sedative drugs are benzodiazepines, intravenous anaesthetic induction agents (e.g. propofol), opiates and α-adrenoreceptor agonists such as dexmedetomidine or clonidine.

Among anesthetic agents, Dexmedetomidine is a strong selective α2-adrenergic agonist with sympatholytic, anxiolytic, analgesic and dose-dependent sedative/hypnotic properties, without causing respiratory depression.

Moreover, the use of dexmedetomidine reduces anesthetic and opioid requirements and also psychomotor function to be reserved.

Dexmedetomidine is the preferred agent for sedation in retinal surgery because of its ability to maintain hemodynamic and respiratory stability.

On the other hand, Propofol is an important intravenous anesthetic agent that has been extensively used as a sedative agent for ophthalmic procedures due to its favorable pharmacokinetic properties. Propofol has short duration of action, no cumulative effect, unique recovery profile as well as rapid emergence and anti-emetic properties. Respiratory depression and reduced blood pressure are major side effects of propofol. However, it has been suggested that propofol may still be safely administered if given at a lower dose. Other side effects of propofol include pain on injection, increased oculocardiac reflex, anaphylaxis and patient movement.

Despite many benefits, propofol sedation has been involved in producing the photic sneezing reflex induced by periocular injections of anesthetics.

Unexpected or sudden sneezing during injection can be a dangerous side effect in periocular injection, in which abrupt head movement may cause globe injury.