[Comparative clinical evaluation of 4 heat and moisture exchangers (HME) in general anesthesia]. / Valutazione clinica comparativa di quattro scambiatori di calore e umidità (HME) in corso di anestesia generale.

ABSTRACT

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.