Tidal Volume Estimation during Helmet Noninvasive Ventilation: an Experimental Feasibility Study.

We performed a bench (BS) and human (HS) study to test the hypothesis that estimation of tidal volume (VT) during noninvasive helmet pressure support ventilation (nHPSV) would be possible using a turbine driven ventilator (TDV) coupled with an intentional leak single-limb vented circuit. During the BS a mannequin was connected to a lung simulator (LS) and at different conditions of respiratory mechanics, positive end expiratory pressure (PEEP) levels and leaks (30, 50 and 80 L/min). All differences were within the 95% limits of agreement (LoA) in all conditions in the Bland-Altman plot. The overall bias (difference between VT measured by TDV and LS) was 35 ml (95% LoA 10 to 57 ml), 15 ml (95% LoA -40 to 70 ml), 141 ml (95% LoA 109 to 173 ml) in the normal, restrictive and obstructive conditions. The bias at different leaks flow in normal condition was 29 ml (95% LoA 19 to 38 ml). In the HS four healthy volunteers using nHPSV had a pneumotachograph (P) inserted through a mouthpiece to measure subject's VT.The bias showed a scarce clinical relevance. In conclusions, VT estimation seems to be feasible and accurate in all conditions but the obstructive one. Additional leaks seem not to affect VT reliability.

Regional anticoagulation with heparin of an extracorporeal CO2 removal circuit: a case report.

BACKGROUND: Extracorporeal carbon dioxide removal is an increasingly used respiratory support technique. As is true of all extracorporeal techniques, extracorporeal carbon dioxide removal needs proper anticoagulation. We report a case of a patient at risk of bleeding complications who was treated with extracorporeal carbon dioxide removal and anticoagulated with a regional technique. CASE PRESENTATION: A 56-year-old Caucasian man with a history of chronic obstructive pulmonary disease exacerbation required extracorporeal carbon dioxide removal for severe hypercapnia and acidosis despite mechanical ventilation. The extracorporeal circuit was anticoagulated using a regional heparin technique to limit the patient's risk of bleeding due to a low platelet count. The patient underwent 96 h of effective extracorporeal carbon dioxide removal without any adverse events. He was successfully weaned from extracorporeal carbon dioxide removal. During the treatment, no bleeding complications or unexpected circuit clotting was observed. CONCLUSIONS: The use of regional heparin anticoagulation technique seems to be feasible and safe during extracorporeal carbon dioxide removal.

Effect of High-Fidelity Simulation on Medical Students' Knowledge about Advanced Life Support: A Randomized Study.

High-fidelity simulation (HFS) is a learning method which has proven effective in medical education for technical and non-technical skills. However, its effectiveness for knowledge acquisition is less validated. We performed a randomized study with the primary aim of investigating whether HFS, in association with frontal lessons, would improve knowledge about advanced life support (ALS), in comparison to frontal lessons only among medical students. The secondary aims were to evaluate the effect of HFS on knowledge acquisition of different sections of ALS and personal knowledge perception. Participants answered a pre-test questionnaire consisting of a subjective (evaluating personal perception of knowledge) and an objective section (measuring level of knowledge) containing 100 questions about algorithms, technical skills, team working/early warning scores/communication strategies according to ALS guidelines. All students participated in 3 frontal lessons before being randomized in group S, undergoing a HFS session, and group C, receiving no further interventions. After 10 days from the end of each intervention, both groups answered a questionnaire (post-test) with the same subjective section but a different objective one. The overall number of correct answers of the post-test was significantly higher in group S (mean 74.1, SD 11.2) than in group C (mean 65.5, SD 14.3), p = 0.0017, 95% C.I. 3.34 - 13.9. A significantly higher number of correct answers was reported in group S than in group C for questions investigating knowledge of algorithms (p = 0.0001; 95% C.I 2.22-5.99) and team working/early warning scores/communication strategies (p = 0.0060; 95% C.I 1.13-6.53). Students in group S showed a significantly higher score in the post-test subjective section (p = 0.0074). A lower proportion of students in group S confirmed their perception of knowledge compared to group C (p = 0.0079). HFS showed a beneficial effect on knowledge of ALS among medical students, especially for notions of algorithms and team working/early warning scores/communication.

Previously undiagnosed Reinke edema as a cause of immediate postextubation inspiratory stridor.

Reinke edema (RE) is an uncommon lesion of the vocal folds and a potential cause of complications during airway management. We report the case of a woman with previously unknown RE admitted to the intensive care unit who experienced postextubation inspiratory stridor immediately after separation from mechanical ventilation. RE should be considered among causes of postextubation stridor.

Can the TLR-4-mediated signaling pathway be "a key inflammatory promoter for sporadic TAA"?

Thoracic aorta shows with advancing age various changes and a progressive deterioration in structure and function. As a result, vascular remodeling (VR) and medial degeneration (MD) occur as pathological entities responsible principally for the sporadic TAA onset. Little is known about their genetic, molecular, and cellular mechanisms. Recent evidence is proposing the strong role of a chronic immune/inflammatory process in their evocation and progression. Thus, we evaluated the potential role of Toll like receptor- (TLR-) 4-mediated signaling pathway and its polymorphisms in sporadic TAA. Genetic, immunohistochemical, and biochemical analyses were assessed. Interestingly, the rs4986790 TLR4 polymorphism confers a higher susceptibility for sporadic TAA (OR = 14.4, P = 0.0008) and it represents, together with rs1799752 ACE, rs3918242 MMP-9, and rs2285053 MMP-2 SNPs, an independent sporadic TAA risk factor. In consistency with these data, a significant association was observed between their combined risk genotype and sporadic TAA. Cases bearing this risk genotype showed higher systemic inflammatory mediator levels, significant inflammatory/immune infiltrate, a typical MD phenotype, lower telomere length, and positive correlations with histopatological abnormalities, hypertension, smoking, and ageing. Thus, TLR4 pathway should seem to have a key role in sporadic TAA. It might represent a potential useful tool for preventing and monitoring sporadic TAA and developing personalized treatments.

Procalcitonin as a marker of Candida species detection by blood culture and polymerase chain reaction in septic patients.

BACKGROUND: The aim of our study is to test procalcitonin (PCT) as surrogate marker of identification of Candida spp. by blood culture (BC) and real-time-polymerase chain reaction (PCR), whether alone or in association with bacteria, in septic patients. METHODS: We performed a single-centre retrospective study. We reviewed the clinical charts of patients with a diagnosis of severe sepsis or septic shock treated at our general intensive care unit from March 2009 to March 2013. We analysed all diagnostic episodes consisting of BC, real-time PCR assay and dosage of PCT. We registered age, sex, white blood count, sequential organ failure assessment score and type of admission between medical or surgical. When inclusion criteria were met more than once, we registered the new diagnostic episode as subsequent diagnostic episode. The diagnostic performance of PCT to predict Candida spp. identification alone or in mixed infections by either BC or PCR was tested using the receiver-operative characteristic curve. Logistic regression was constructed using presence of Candida spp. as the dependent variable. RESULTS: A total of 260 diagnostic episodes met the inclusion criteria. According to BC results classification, a significantly lower value of PCT was observed in Candida spp. BSI (0.99 ng/ml, 0.86 - 1.34) than in BSI caused by bacteria (16.7 ng/ml, 7.65 - 50.2) or in mixed infections (4.76 ng/ml, 2.98 - 6.08). Similar findings were observed considering PCR results. A cut-off of ≤ 6.08 ng/ml for PCT yielded a sensitivity of 86.8%, a specificity of 87.4%, a positive predictive value of 63.9%, a negative predictive value (NPV) of 96.3% and an area under the curve of 0.93 for Candida spp. identification by BC. A similar high NPV for a cut-off ≤ 6.78 ng/ml was observed considering the classification of diagnostic episodes according to PCR results, with an AUC of 0.85. A subsequent diagnostic episode was independently associated with Candida spp. detection either by BC or PCR. CONCLUSION: PCT could represent a useful diagnostic tool to exclude the detection of Candida spp. by BC and PCR in septic patients.

Valve prosthesis-patient mismatch: hemodynamic, echocardiographic and clinical consequences.

OBJECTIVES: The purpose is to evaluate in vivo at rest and under stress conditions hemodynamic performance of the small size St. Jude Medical Regent (SJMR) prosthetic valve in patients with a body surface area (BSA) of 1.8 ± 0.11 m(2) and to define the role of valve prosthesis- patient mismatch on left ventricular mass regression following aortic valve replacement. METHODS: We evaluated 25 cases (12 males and 13 females, mean age 65.2 ± 8 years) of aortic valve replacement (17 mm SJMR in three cases and 19 mm SJMR in 22 cases). All the patients underwent at rest Doppler echocardiography before and after surgery and both basal and dobutamine stress echocardiography (DSE) at follow-up. The mean duration of follow-up was 41.3 ± 24 months. RESULTS: A significant reduction in mean and peak transaortic gradients and peak transaortic velocity over time following valve replacement has been identified. After surgery, there was a significant increase of ejection fraction. DSE significantly increased heart rate, ejection fraction, peak transaortic gradient and peak transaortic velocity. All patients passed DSE without complication. Even if a significant mismatch was present in 76% of cases, the left ventricular mass decreased significantly from preoperative value of 278.7 ± 51.1 g to 181.5 ± 52.73 g, respectively. CONCLUSION: Aortic valve replacement with 17 mm SJMR or 19 mm SJMR prostheses appear to provide satisfactory clinical and hemodynamic results at rest and under DSE, even in those patients with BSA of 1.8 ± 0.11 m(2) where it was not possible to enlarge the aortic annulus. Prosthesis-patient mismatch is not associated with lesser regression of left ventricular mass. Dobutamine stress echocardiography should be a useful and effective means for evaluating prosthesis hemodynamic aspects.