98th Annual Meeting DOG 2000

K 754

Opioids reduce stress responses during ophthalmic surgery in local anaesthesia

F. C. Schlichtenbrede1, M. C. Bartram1, K. U. Burkhardt2

Background: Preoperative stress caused even by minor procedures in ophthalmic surgery often induces cardiovascular problems such as hypertension and arrhythmia in the elderly patient. Both the psychological distress and the pain of the peribulbar injection of local anaesthetic provoke an increase in catecholamines (adrenaline and noradrenaline). The pre-medication with midazolam is routinely used to maintain a stable cardivascular condition, but the standard dose of 0.05 mg/kg body weight p.o. proved unsatisfactory in reducing these effects in our daily practice. To reduce preoperative stress and therefore to increase both patient comfort and safety the opi-oid piritramide was administered intravenously prior to local anaesthesia.

Patients and Methods: 28 informed and consenting patients were randomised in two groups. All patients were pre-treated 60 minutes prior to surgery with midazolam p.o. followed by a standardised peribulbar injection of 6 ml bupivacaine 40 minutes later. Patients in group 2 were additionally treated with piritramide at a dose of 0.025 mg/kg body weight 5 minutes prior to the injection. To record the stress response, both clinical signs (blood pressure, heart rate, oxygen-saturation, ECG) were monitored at set points during the procedure. Endocrine stress parameters were evaluated by determining serum catecholamines in a simultaneously taken blood sample using HPLC. Additionally both patient and surgeon provided a subjective anxiety ranking.

Results: In all cases co-operation was good and the surgical procedure was conducted without complications. Clinical signs (blood pressure, heart rate) were elevated in group 1 as compared to the opioid-treated group at the time of local anaesthesia. There were no significant differences in the changes of noradrenaline-levels relative to the base-value between the groups. Adrenaline-levels showed significantly lower relative changes in the opioid-treated group. The subjective anxiety ranking in this group also showed a considerably lower grade, as judged both by the patient and the surgeon.

Conclusions: The additional intravenous application of piritramide prior to local an-aesthesia significantly reduces cardiovascular stress responses as well as subjective anxiety grades. This considerably increases the patient comfort and may lead to safer surgical procedures without adding risk factors. We therefore propose the introduction of an opioid pre-treatment into the routine of local anaesthesia in ophthalmology, provided that adequate monitoring is available.

Leipzig University, 1Dept. Ophthalmology and 2Dept. Anaesthesiology, Germany