[Brief narcosis with propofol/ketamine for administering retrobulbar anesthesia]

Eye surgery is performed under local anesthesia in more than 90% of the cases. While injecting the local anesthetics a deep sedation is desired. During surgery however the patient should be cooperative, such as to avoid inadvertent movements. We routinely perform local anesthesia (retrobulbar injection and van Lint block) under intravenous anesthesia with propofol (Disoprivan) and ketamine (Ketalar, Ketanest).

To control safety and efficacy of this method a prospective study was performed including 100 consecutive patients. The results were to be compared with an earlier study where 35 Patients received midazolam (Dormicum) and alfentanil (Rapifen) as sedation. The actual protocol included the following points: 1. Personal judgement of the patient. 2. Conditions to perform the retrobulbar injection, 3. Intraoperative conditions and additional sedation, 4. Pulse, blood pressure and blood oxygen concentration, 5. Complications

> 95% of the patients had a total amnesia of the injection of local anesthetics. Retrobulbar injection is comfortable (96%), but may be difficult in patients with a narrow orbit and exotropia (4%). Intraoperative conditions were noted as good in 97%. Additional sedation during surgery was necessary in 3%. Blood pressure and pulse remained stable. Blood oxygen concentration showed a tendency to sink during intravenous anesthesia. This could be managed easily by additional oxygen via face mask if necessary. Postoperative emesis was noted in 3%. No further ocular complications occurred that might be related to the anesthetic management. In an earlier study including 35 Patients under comparable conditions we used midazolam and alfentanil for sedation. The results were similar. Midazolam and alfentanil were then used in over 2000 operations. Often the patients were deeply sedated and asleep during surgery which meant a potential risk of a sudden awakening and moving the head inadvertently. Occasionally paradoxical reactions occurred after midazolam.

Using propofol and ketamine while performing the local anesthesia the patients are awake but relaxed and cooperative during surgery. This method has now been used routinely in over 1000 cases. It has proved to be clinically safe and efficient. It offers the surgeon good working conditions and is well tolerated by the patients, reducing their preoperative and perioperative anxieties.