Volume-controlled ventilation has been suggested to optimize lung deposition during nebulization although promoting spontaneous ventilation is targeted to avoid ventilator-induced diaphragmatic dysfunction. Comparing topographic aerosol lung deposition during volume-controlled ventilation and spontaneous ventilation in pressure support has never been performed. The aim of this study was to compare lung deposition of a radiolabeled aerosol generated with a vibrating-mesh nebulizer during invasive mechanical ventilation, with two modes: pressure support ventilation and volume-controlled ventilation. Seventeen postoperative neurosurgery patients without pulmonary disease were randomly ventilated in pressure support or volume-controlled ventilation. Diethylenetriaminepentaacetic acid labeled with technetium-99m (2 mCi/3 mL) was administrated using a vibrating-mesh nebulizer (Aerogen Solo®, provided by Aerogen Ltd, Galway, Ireland) connected to the endotracheal tube. Pulmonary and extrapulmonary particles deposition was analyzed using planar scintigraphy. Lung deposition was 10.5 ± 3.0 and 15.1 ± 5.0 % of the nominal dose during pressure support and volume-controlled ventilation, respectively (p < 0.05). Higher endotracheal tube and tracheal deposition was observed during pressure support ventilation (27.4 ± 6.6 vs. 20.7 ± 6.0 %, p < 0.05). A similar penetration index was observed for the right (p = 0.210) and the left lung (p = 0.211) with both ventilation modes. A high intersubject variability of lung deposition was observed with both modes regarding lung doses, aerosol penetration and distribution between the right and the left lung. In the specific conditions of the study, volume-controlled ventilation was associated with higher lung deposition of nebulized particles as compared to pressure support ventilation. The clinical benefit of this effect warrants further studies. Clinical trial registration NCT01879488

Gross total or near total resection (GTR/NTR; resection ≥95%) of glioblastoma (GBM) seems correlated with a longer survival. Intraoperative MRI (ioMRI) is one method to evaluate the extent of resection (EOR) in order to improve it during the same anesthesia. We compared GBM resections using a 3.0T ioMRI and then without considering the EOR, safety, survival and discussed the indications for using this expensive modality. Between March 2006 and November 2011, 56 GBM resections were performed using an ioMRI, and 38 without (control group). The only criterion in order to have access to the ioMRI was its availability. We compared the variables EOR, Karnofsky Performance Scale scores and survival in both groups. In the ioMRI group, 15 patients (26.8%) underwent an immediate second resection increasing the GTR rate of 10.7% and the GTR/NTR rate of 8.9%. There was a significant difference between the use of an ioMRI and the control group in reaching a larger EOR (P=0.049, Fisher's exact test). The effect of using the ioMRI or not on the overall survival, with EOR as covariate, was not significant (P=0.147, Likelihood ratio test). However, the EOR alone had a significant effect on survival (P=0.049, Wald test), with a shorter survival for the patients with a partial resection (PR) than a GTR/NTR (Hazard ratio=1.6, 95% CI HR: 1.00-2.69), with a median overall survival of 15.26 months (95% CI: 12.34-19.08) for the GTR/NTR subgroup versus 10.26 months (95% CI: 6.64-15.82) for the PR subgroup. Multivariate regression analysis also identified age, sex and adjuvant chemotherapy as factors significantly associated with overall survival. A 3.0T ioMRI improved the quality of resection by 17.8% and increased the GTR/NTR rate by 8.9% up to 73.2% without additional morbidity. A GTR/NTR improves survival duration by about 50%. Thus, it remains reasonable to increase the EOR to reach GTR/NTR using an intraoperative control. However, ioMRI should be limited to the cases for which a GTR/NTR seems preoperatively possible.