[Comparative clinical evaluation of 4 heat and moisture exchangers (HME) in general anesthesia].

OBJECTIVE

To determine the efficiency, during general anaesthesia, of four commercially available HMEs, with particular attention to the change of performances due to the new modifications introduced by the manufacturers.

DESIGN

Comparisons of the performances of each HMEs with psychometric method in terms of T degree C, RH (%), AH (mgH2O/1) of inhaled and expired gases.

PATIENTS

A sample of 28 patients under general anesthesia longer than 150 minutes, undergone elective urological surgery. Patients with cardiological, respiratory and metabolic impairments have been excluded.

MEASUREMENTS AND RESULTS

The measurements of T degree C, RH and AH have been performed with thermometric probes every minute. The collected data have been analyzed by Student's "t"-test for unpaired data.

CONCLUSIONS

The obtained data show that a good conditioning of the inhaled gases is possible, although only few HMEs satisfy the requirements indicated in the ISO and BSI standards.