[The hemodynamic effects of atracurium in geriatric patients during intravenous anesthesia using propofol]

Neuromuscular blocking drugs may produce cardiovascular effects by virtue of drug-induced release of histamine or other vasoactive substances from circulating mast cells, effects at cardiac muscarinic receptors or effects at nicotinic receptors at autonomic ganglia. These haemodynamic reactions may be more pronounced in elderly patients, since cardiovascular compensating mechanisms are attenuated with advancing age. The present study was designed to investigate the cardiovascular effects of atracurium with special regard to the reactions in younger adults and in elderly patients.

20 patients, ASA class I-II, who underwent a neurosurgical operation (posterior fossa surgery) were studied. The patients were divided into two groups including patients below (group A) and above (group B) 65 years of age. Anaesthesia was induced with propofol (2.5 mg/kg) and maintained with a Propofol/O2/N2O sequence. Under steady state conditions with propofol every patient received 0.5 mg/kg atracurium besylate. Haemodynamic parameters were recorded and plasma concentrations of epinephrine and norepinephrine were determined before (control) and 2, 5 and 10 minutes after the injection of the neuromuscular blocking agent. All measurements were performed before surgical stimulation in supine position.

In the younger adults diastolic blood pressure and systemic vascular resistance decreased significantly 2 minutes after injection of atracurium and reached control level 5 minutes after application of the muscle relaxant. In the elderly patients peripheral vascular resistance decreased significantly after 5 minutes and returned to control 10 minutes after the application of atracurium. In both groups cardiac index, systolic and mean arterial pressure, central venous pressure and the parameters related to the pulmonary circulation were not affected. Plasma concentrations of epinephrine and norepinephrine remained essentially unchanged. Side effects due to a release of histamine such as facial or body blush or bronchial spasms were not noted.

Since the results of the present study suggest that haemodynamic reactions in younger adults and in the elderly are rare, atracurium can be recommended for neuromuscular blockade in elderly patients under propofol anaesthesia.