[Comparison of 2 systems for continuous intraoperative monitoring of oxygen saturation in the jugular bulb].

OBJECTIVE

To compare accuracy, precision and stability of two jugular venous blood catheters for continuous monitoring of oxygen saturation during surgery, in a nonrandom, prospective sample.

PATIENTS AND METHODS

We studied 47 patients requiring continuous monitoring of SjvO2 during a variety of neurosurgical procedures. Swan-Ganz pediatric 5.5F catheters (Opticath P575-EH) were used in 27 patients; neonatal umbilical artery 4F catheters (Opticath U425C) were used in 20. Both catheters were equipped with a fiberoptic system for continuous monitoring of hemoglobin oxygen saturation. After checking correct placement, readings transmitted were compared with co-oximetry readings for a sample taken from the distal end of the catheter. We also compared time spent placing the catheters and stability of SjvO2 reading during surgery.

RESULTS

Insertion time (+/- SD) was 10.3 +/- 2.5 minutes for the 4F catheter and 15.9 +/- 5.5 minutes for the 5.5F model (p < 0.01). Although both systems tended to overestimate, the 5.5F catheters were more accurate: the mean differences were -6.8% for the 4F catheter and -1.2% for the 5.5F. These results made it necessary to calibrate the 4F catheters after placement and before use, a procedure not needed if the 5.5F catheters are used. Stability of SjvO2 readings during surgery was significantly greater (p < 0.01) for the 5.5F catheters, such that only 25.9% were considered clinically useful based on this parameter. However, 70% of the 5.5F catheters provided acceptable SjvO2 readings. Intracranial pressure during insertion and removal of the SjvO2 catheters was measured in only 5 patients; there were no changes greater than 1 mmHg.

CONCLUSIONS

Although the 5.5F pediatric catheters take longer to put into position, their greater accuracy, precision and stability makes them preferable to the 4F catheters for continuous monitoring of SjvO2. Long-term vascular effects must be studied further.