Modifications of lung microbiota structure in traumatic brain injury ventilated patients according to time and enteral feeding formulas: a prospective randomized study.

BACKGROUND: Specialized diets enriched with immune nutrients could be an important supplement in patients (pts) with acute traumatic brain injury (TBI). Omega-3 and arginine may interact with immune response and microbiota. No data are available about the role of the specialized diets in modulating the lung microbiota, and little is known about the influence of lung microbiota structure in development of ventilator-associated pneumonia (VAP) in TBI pts. The aims of this study are to evaluate the impact of specific nutrients on the lung microbiota and the variation of lung microbiota in TBI pts developing VAP. METHODS: A cohort of 31 TBI pts requiring mechanical ventilation in ICU was randomized for treatment with specialized (16pts) or standard nutrition (15pts). Alpha and beta diversity of lung microbiota were analyzed from bronco Alveolar Lavage (BAL) samples collected at admission and 7 days post-ICU admission in both groups. A further analysis was carried out on the same samples retrospectively grouped in VAP or no VAP pts. RESULTS: None developed VAP in the first week. Thereafter, ten out of thirty-one pts developed VAP. The BAL microbiota on VAP group showed significant differences in beta diversity and Staphylococcus and Acinetobacter Genera were high. The specialized nutrition had influence on beta diversity that reached statistical significance only in Bray-Curtis distance. CONCLUSION: Our data suggest that TBI patients who developed VAP during ICU stay have different structures of BAL microbiota either at admission and at 7 days post-ICU admission, while no correlation has been observed between different enteral formulas and microbiota composition in terms of richness and evenness. These findings suggest that targeting the lung microbiota may be a promising approach for preventing infections in critically ill patients.

The anaesthetic and recovery profile of two concentrations (0.25% and 0.50%), of intrathecal isobaric levobupivacaine for combined spinal-epidural (CSE) anaesthesia in patients undergoing modified Stark method caesarean delivery: a double blinded randomized trial.

BACKGROUND: In spinal anaesthesia for a Caesarean delivery, it is important to limit anaesthesia only at the surgical area, and to resolve fast motor block. We compared the intraoperative effectiveness, hemodynamic effects, anaesthetic recovery times and patients satisfaction after isobaric levobupivacaine (L) 0.25% versus L0.50% spinal anaesthesia during elective Caesarean deliveries performed with the Stark technique. PATIENTS AND METHODS: In this double-blinded prospective study, seventy women undergoing elective caesarean delivery were randomized to receive either intrathecal 7.5 mg Levobupivacaine 0.25% plus sufentanil 2.5 µg (Group L0.25), or intrathecal 7.5 mg L 0.50% plus sufentanil 2.5 µg (GroupControl). The onset time, duration of anaesthesia, analgesia and sensory and motor block and hemodynamic parameters were measured from the beginning of spinal anaesthesia until four hours after spinal anaesthesia (T240). RESULTS: Onset time, duration of anaesthesia and haemodynamic variations were similar in the two groups. No patients required general anesthesia to complete surgery. Motor block vanished faster in Group L0.25 as compared with GroupControl (p < .01). The cephalad spread of the 0.50% solution was higher than that of the 0.25% solution: no patient in Group L0.25 experienced paresthesia of the upper limbs vs 14% in GroupControl (p < .05). In GroupControl anaesthesia reached the dermatome T1 in 15% of cases. Maternal and surgeon satisfaction was good in every patient. CONCLUSIONS: Levobupivacaine 7.5 milligrams at 0.25% may be used as a suitable alternative to L 0.50% for spinal anaesthesia for caesarean deliveris with the Stark technique with good maternal satisfaction. In Group L0.25 a lower appearance of nausea and hypotension were observed and motor and sensitive block developed and diminished faster while no clinically significant differences in hemodynamic behavior was observed between groups.

Models of cardiac tissue electrophysiology: progress, challenges and open questions.

Models of cardiac tissue electrophysiology are an important component of the Cardiac Physiome Project, which is an international effort to build biophysically based multi-scale mathematical models of the heart. Models of tissue electrophysiology can provide a bridge between electrophysiological cell models at smaller scales, and tissue mechanics, metabolism and blood flow at larger scales. This paper is a critical review of cardiac tissue electrophysiology models, focussing on the micro-structure of cardiac tissue, generic behaviours of action potential propagation, different models of cardiac tissue electrophysiology, the choice of parameter values and tissue geometry, emergent properties in tissue models, numerical techniques and computational issues. We propose a tentative list of information that could be included in published descriptions of tissue electrophysiology models, and used to support interpretation and evaluation of simulation results. We conclude with a discussion of challenges and open questions.

Physiological effects of a lung-recruiting strategy applied during one-lung ventilation.

BACKGROUND: One-lung ventilation (OLV) affects respiratory mechanics and ventilation/perfusion matching, reducing functional residual capacity of the ventilated lung. While the application of a lung-recruiting manoeuvre (RM) on the ventilated lung has been shown to improve oxygenation, data regarding the impact of RM on respiratory mechanics are not available. METHODS: Thirteen patients undergoing lung resection in lateral decubitus were studied. During OLV, a lung-recruiting strategy consisting in a RM lasting 1 min followed by the application of positive end-expiratory pressure 5 cmH(2)O was applied to the ventilated lung. Haemodynamics, gas exchange and respiratory mechanics parameters were recorded on two-lung ventilation (TLV(baseline)), OLV before and 20 min after the RM (OLV(pre-RM), OLV(post-RM), respectively) and TLV(end). Haemodynamics parameters were also recorded during the RM. RESULTS: The PaO(2)/FiO(2) ratio was 358+/-126 on TLV(baseline); it decreased to 235+/-113 on OLV(pre-RM) (P<0.01) increased to 351+/-120 on OLV(post-RM) (P<0.01 vs. OLV(pre-RM)), and remain stable thereafter. During the RM, CI decreased from 3.04+/-0.7 l/m(2) OLV(pre-RM) to 2.4+/-0.6 l/m(2) (P<0.05), and returned to baseline on OLV(post-RM) (3.1+/-0.7 l/m(2), NS vs. OLV(pre-RM)). The RM resulted in alveolar recruitment and caused a significant decrease in static elastance of the dependent lung (16.6+/-8.9 cmH(2)O/ml OLV(post-RM) vs. 22.3+/-8.1 cmH(2)O/ml OLV(pre-RM)) (P<0.01). CONCLUSIONS: During OLV in lateral decubitus for thoracic surgery, application to the dependent lung a recruiting strategy significantly recruits the dependent lung, improving arterial oxygenation and respiratory mechanics until the end of surgery. However, the transient haemodynamic derangement occurring during the RM should be taken into account.