Effects of ventilation mode and manual chest compression on flow bias during the positive end- and zero end-expiratory pressure manoeuvre in mechanically ventilated patients: a randomised crossover trial.

OBJECTIVES: To investigate the effects of ventilation mode and manual chest compression (MCC) application on the flow bias generated during positive end-expiratory pressure-zero end-expiratory pressure (PEEP-ZEEP) in mechanically ventilated patients. PEEP-ZEEP is an airway clearance manoeuvre with the potential to exceed the flow bias required to remove secretions. However, the ventilation mode applied during the manoeuvre has not been standardised. DESIGN: Randomised crossover trial. PARTICIPANTS: Nineteen mechanically ventilated patients. INTERVENTIONS: Patients were randomised to receive PEEP-ZEEP in volume-controlled and pressure-controlled modes, and with or without MCC. MAIN OUTCOME MEASURES: The difference in flow bias - assessed by the peak expiratory flow (PEF) and peak inspiratory flow (PIF) ratio and difference - between PEEP-ZEEP applied in both ventilation modes, and with and without MCC. RESULTS: The expiratory flow bias was significantly higher in the volume-controlled mode than the pressure-controlled mode. This result was caused by a lower PIF in the volume-controlled mode. PEEP-ZEEP applied in the pressure-controlled mode did not achieve the PEF-PIF difference threshold to clear mucus. Moreover, in the majority of cycles of PEEP-ZEEP applied in the pressure-controlled mode, an inspiratory flow bias was generated, which might embed mucus. PEF was 8l/minute higher with MCC compared with without MCC, which increased the PEF-PIF difference by the same amount. No haemodynamic or respiratory adverse effects were found. CONCLUSIONS: If applied in the volume-controlled mode, PEEP-ZEEP can achieve the flow bias needed to expel pulmonary secretions. However, this is not the case in the pressure-controlled mode. MCC can augment the flow bias generated by PEEP-ZEEP, but its application may be dispensable. CLINICAL TRIAL REGISTRATION: http://www.ensaiosclinicos.gov.br/rg/RBR-223xv8/.

Treatment of epiphora in connection with endolacrimal surgery using trephines: new and overview data.

BACKGROUND: To provide new and to summarize published data on endolacrimal surgery with Piffaretti's trephines, in particular in patients having patent lacrimal drainage system (syringing) and epiphora resistant to medical treatments. PATIENTS AND METHODS: From two tertiary referral centers (Basel/Switzerland; Belo Horizonte/Brazil), 126 patients undergoing endolacrimal surgery with Piffaretti's trephines, combined, when clinically indicated, with other procedures known to improve epiphora (canthoplasty/pexie and/or conjunctivochalasisplasty). RESULTS: I) A study (Basel) in 17 patients showed one-year after surgery marked epiphora symptoms' improvement in 88% (15/17) of patients, 65% (11/17) being symptom-free. II) Unpublished data (Belo Horizonte) in 42 patients found 81% (34/42) symptom-free six-months after surgery. Dacryoscintigraphy illustrated postoperative tears' clearance improvement. III) Unpublished data (Belo Horizonte) in 45 patients solely undergoing endolacrimal surgery for complete ductal obstruction found symptom-free, six-months after surgery, 27% (8/30) of patients with preoperatively enlarged lacrimal sac and 80% (12/15) with none-enlarged sac (p < 0.01, Fisher's test). IV) A study (Basel) in 22 epiphora patients reported no correlation (p = 0.62, rho -0.11, Spearman) between preoperative basal Schirmer's test II (oxybuprocain-HCL 0.4%) values and one-year surgical outcome. Patients with preoperative Schirmer's test's values ≤ or > 6 mm had similar mean postoperative symptoms' improvement (82 ± 30%, n = 11 vs. 76 ± 34%, n = 11, p = 0.97, Mann-Whitney). CONCLUSIONS: Endolacrimal surgery with Piffaretti's trephines, sometimes combined, when clinically indicated, with other procedures also known to ameliorate epiphora, can in particular improve (different conditions, surgeons, centers) epiphora's symptoms resistant to medical treatments in patients with patent lacrimal drainage system, and this apparently, even when pre-operative basal Schirmer-test values are low. By enlarged lacrimal sac, outcome is poor.

Influence of structural disorder on the photoluminescence emission of PZT powders.

Intense and broad visible photoluminescent (PL) band was observed at room temperature in disordered Pb(Zr0.53Ti0.47)O3 powders. Structural order-disorder was evaluated by different methods. XANES results pointed to the presence of different coordination modes of disordered Ti powders, and in the ordered sample the local structure around titanium atoms is characteristic of the structurally ordered PZT with only TiO6 units. Only samples containing simultaneous structural order and disorder in their network present the intense visible PL emission at room temperature.

Teratogenicity of Mimosa tenuiflora seeds to pregnant rats.

Bone and other malformations caused by the ingestion of Mimosa tenuiflora are common in ruminants in the Brazilian semiarid. The aim of this research was to study the teratogenic effects of M. tenuiflora in Wistar rats (Rattus novergicus). The experimental group had 15 females and was fed, from the 6th to the 21st day of pregnancy, with a ration containing 10% of M. tenuiflora seeds. The control group, with 10 females, was fed with the same ration without seeds. There were no differences in weight gains, and food and water consumption between treated and control rats. Ninety bone malformations were observed in 40 of the 101 fetuses born in the experimental group, and four malformations were observed in three of the 58 fetuses born in the control group (p<0.05). The weight and number of ossification centers of the fetuses from the experimental group were higher than those from the control group (p<0.05). It is concluded that the seeds of M. tenuiflora are teratogenic to rat fetuses.

Fungal flora of the digestive tract of Panstrongylus megistus (Reduviidae) used for experimental xenodiagnosis of Trypanosoma (Schizotripanum) cruzi Chagas, 1909.

A survey of the fungi isolated from the digestive tract of Panstrongylus megistus (insects vectors from Chagas' disease) used on xenodiagnosis was carried out. Two hundred and fourteen fungal strains were isolated from 180 nymphs. Aspergillus and Penicillium were the most predominant genera and some of their species were new records concerning insects. A great reduction in the fungal population was observed in the material that was positive for Trypanosoma cruzi.