We described an EIT-based method for estimating recruitable alveolar collapse at the bedside, pointing out its regional distribution. Additionally, we proposed a measure of lung hyperdistension based on regional lung mechanics.

The assessment of the regional match between alveolar ventilation and perfusion in critically ill patients requires simultaneous measurements of both parameters. Ideally, assessment of lung perfusion should be performed in real-time with an imaging technology that provides, through fast acquisition of sequential images, information about the regional dynamics or regional kinetics of an appropriate tracer. We present a novel electrical impedance tomography (EIT)-based method that quantitatively estimates regional lung perfusion based on first-pass kinetics of a bolus of hypertonic saline contrast. Pulmonary blood flow was measured in six piglets during control and unilateral or bilateral lung collapse conditions. The first-pass kinetics method showed good agreement with the estimates obtained by single-photon-emission computerized tomography (SPECT). The mean difference (SPECT minus EIT) between fractional blood flow to lung areas suffering atelectasis was -0.6%, with a SD of 2.9%. This method outperformed the estimates of lung perfusion based on impedance pulsatility. In conclusion, we describe a novel method based on EIT for estimating regional lung perfusion at the bedside. In both healthy and injured lung conditions, the distribution of pulmonary blood flow as assessed by EIT agreed well with the one obtained by SPECT. The method proposed in this study has the potential to contribute to a better understanding of the behavior of regional perfusion under different lung and therapeutic conditions.

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In order to evaluate the association between serum vitamin A levels and ocular lesions attributable to non-complicated malaria, 200 patients seen consecutively at the Malaria Outpatient Clinic of FUNASA, Manaus, Amazonas, Brazil were included in this study. Ophthalmologic examination consisted of indirect binocular ophthalmoscopy under medicamentous mydriasis, biomicroscopy with a portable slit lamp and measurement of central visual acuity. Vitamin A serum concentration was determined by HPLC, and deficiency was defined as serum values equal to or lower than 0.35 micromol/l. Serum vitamin A values between 0.36 and 0.70 micromol/l were considered as marginal levels. Hypovitaminosis A (