[Effects of propofol on blood concentration of cyclosporine]

OBJECTIVE

This study was designed to assess whether propofol modifies the blood concentrations of cyclosporine and lipoproteins, which bind cyclosporine.

STUDY DESIGN

Prospective open study.

PATIENTS

Fifteen consecutive grafted patients, scheduled for surgery allowing them to resume their oral treatment postoperatively. Their immunosuppressive treatment, included cyclosporine (Cy A), at a steady-state dosage.

METHODS

Blood samples were drawn and residual Cy A blood concentrations were measured the days before and after anaesthesia and before and immediately after discontinuing the propofol infusion. Serum triglycerides, cholesterol, high-density lipoprotein (HDL) concentrations were measured before and immediately after discontinuing the propofol infusion.

RESULTS

The 15 patients were given propofol by infusion for 30-210 min (mean 85 +/- 59 min). They received a total dose of propofol of 696 +/- 497 mg, a total fentanyl dose of 175 +/- 82 micrograms, and a total midazolam dose of 2.8 +/- 0.8 mg. The residual cyclosporine blood concentrations were similar the day before (142 +/- 47 ng.mL-1) and following anaesthesia (128 +/- 46 ng.mL-1) (P = 0.08). Serum cholesterol concentrations were not significantly influenced by propofol infusion, but serum triglycerides levels increased (1.46 +/- 0.66 vs 1.97 +/- 0.81 g.L-1), and HDL and LDL levels decreased (0.54 +/- 0.20 vs 0.47 +/- 0.18 g.L-1; 1.44 +/- 0.42 vs 1.28 +/- 0.37 g.L-1).

CONCLUSION

Propofol by infusion does not modify the cyclosporine concentration. It is concluded that propofol may be a suitable agent for intravenous anaesthesia in cyclosporine treated patients, provided a close postoperative monitoring of cyclosporine blood concentrations is maintained.

[A new anesthetic protocol in experimental ocular surgery in rabbits]

The authors describe a new anaesthetic protocol for laboratory rabbits. The surgery consists in an extracapsular lens extraction with intraocular lens implantation in the bag. The anaesthetic protocol requires: an intravenous induction with ketamine (20.2 mg/kg +/- 5) and midazolam (0.65 mg/kg +/- 0.3) and after an oral endotracheal intubation with a simple method, and at last maintaining halothane anaesthesia with a concentration between 3 and 4%. 45 anaesthesia were performed: the average time of the anaesthesia was 77 min +/- 16. No rabbit died because of this anaesthesia. The anaesthesia was a success for the surgeon who could operate in the best working conditions.

[Measurement of cardiac output by thoracic electrical bioimpedance or thermodilution]

The present study was designed to assess a new non invasive method for measuring cardiac output. The thoracic electrical bioimpedance method was compared with the reference one, thermodilution. The measurements were made simultaneously with NCCOM3 (bioimpedance) using the freeze data mode, and with a Swan-Ganz catheter and a haemodynamic computer (thermodilution). The study involved 11 spontaneously breathing patients in a steady haemodynamic state. Ten measurements were carried out with both methods for each patient. Statistical analysis of the 110 paired values was carried out by computer. The various statistical tests applied confirmed that there was a highly significant correlation between values for cardiac output obtained by each of these two methods (r = 0.818; p less than 0.005); they also showed a significantly more important dispersion of the measures for each patient with thermodilution. The mean value of the thermodilution "standard deviation" (0.64 l.min-1) was significantly more important (p less than 0.005) than the one with NCCOM3 (0.24 l.min-1). Thoracic electrical bioimpedance appeared a safe method for measuring cardiac output, providing the limits of the method are kept. The objective is not to replace the Swan-Ganz catheter, but to propose an alternative method for measuring cardiac output. This method is very interesting in many circumstances, particularly for intensive care patients: it is a non invasive technique, continual measurement is not time-limited, and its use is very easy.