Objective: To study the effect of prone position on respiratory mechanics. Design: Prospective study.

Setting: Spine elective surgery at a university hospital. Patients: 12 ASA physical I & II with no coexisting cardiorespiratory disease undergoing cervical or lumbar laminectomy. Measurements: Ten min after induction of general anaesthesia while patients were in supine position, the following measurements were taken using anaesthesia delivery unit (Datex Ohmeda type A_Elec, Promma, Sweden): peak airway pressure (Ppeak), peak plataeu pressure (Pplat), peak mean pressure (Pmean) and dynamic lung compliance (DLC). The same measurements were performed 10 min after changing to prone position. At the end of surgery and 5 min after turning the patients supine and before tracheal extubation, the same measurements were again performed. Statistical analysis were performed using SPSS 9.0 for Windows; SPSS Inc., Chicago, IL. The results expressed as means ± SD. One way ANOVA was used for analysis of differences in the data before, during prone position and after turning patients supine at the end of the procedure. For all comparisons p<0.05 was considered significant. Results: During prone position there was significant reduction in DLC. Also we noticed a significant increase in airway pressures compared to that in the supine position. Conclusion: We concluded that turning the patients from supine to prone position during anaesthesia decreases respiratory mechanics variables including DLC. Key words: Surgical positions, lung compliance,lumbar discectomy Address correspondense: PDF created with FinePrint pdfFactory trial versio