Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 260)

A bibliography containing 225 reports, articles, and other documents which were introduced into the NASA Scientific and Technical Information system in June 1984 is presented. All articles are indexed and abstracted. General topics include: life sciences, aerospace medicine, behavioral sciences, man/system technology and life support, and planetary biology

The conditioning of medical gases with hot water humidifiers

During invasive mechanical ventilation due to the dryness of medical gases is necessary to provide an adequate level of conditioning. The hot water humidifiers (HWH) heat the water, thus allowing the water vapor to heat and humidify the medical gases. In the common HWH there is a contact between the medical gases and the sterile water, thus increasing the risk of patient’s colonization and infection. Recently to avoid the condensation in the inspiratory limb of the ventilator circuit, new heated ventilator circuits have been developed. In this in vitro study we evaluated the efficiency (absolute/relative humidity) of three HWH: (1) a common HWH without a heated ventilator circuit (MR 730, Fisher&Paykel, New Zeland), (2) the same HWH with a heated ventilator circuit (Mallinckrodt Dar, Italy) and (3) a new HWH (DAR HC 2000, Mallinkckrodt Dar, Italy) with a heated ventilator circuit in which the water vapor reaches the medical gases through a gorotex membrane, avoiding any direct contact between the water and gases. At a temperature of 35°C and 37°C the HWH and heated tube were evaluated. The absolute humidity (AH) and relative humidity (RH) were measured by a psychometric method. The minute ventilation, tidal volume respiratory rate and oxygen fraction were: 5.8 ± 0.1 l/min, 740 ± 258 ml, 7.5 ± 2.6 bpm and 100%, respectively. Ventilator P2 Use of a bougie during percutaneous tracheostom

Strain threshold for ventilator-induced lung injury

Introduction Unphysiological lung strain (tidal volume/functional residual capacity, TV/FRC) may cause ventilator-induced lung injury (VILI) [1]. Whether VILI develops proportionally to the applied strain or only above a critical threshold remains unknown. Methods In 20 healthy, mechanically ventilated pigs, FRC and lung weight were measured by computed tomography. Animals were then ventilated for up to 54 hours with a TV set to produce a predetermined strain. At the end, lung weight was measured with a balance. VILI was defi ned as fi nal lung weight exceeding the initial one. Results Lung weight either did not increase at all (no-VILI group; lung weight change \u201373 \ub1 42 g, n = 9) or markedly augmented (VILI group; 264 \ub1 80 g, n = 11). In the two groups, strain was 1.38 \ub1 0.68 and 2.16 \ub1 0.50 (P <0.01), respectively. VILI occurred only when lung strain reached or exceeded a critical threshold, between 1.5 and 2.1 (Figure 1). Conclusions In animals with healthy lungs VILI only occurs when lung strain exceeds a critical threshold. Reference 1. Gattinoni L, Carlesso E, Cadringher P, et al.: Physical and biological triggers of ventilator-induced lung injury and its prevention [review]. Eur Respir J 2003, 22(Suppl 47):15s-25s

A radiological visual scale to predict the potentially recruitable lung in ALI/ARDS patients

Introduction In ALI/ARDS patients the amount of potentially recruitable lung is extremely variable and it is poorly predictable by the changes of oxygenation, carbon dioxide or compliance during a PEEP trial [1]. At the present time the gold standard to compute the lung recruitability is the quantitative lung CT scan, in which each lung image, after being manually drawn, is analyzed by dedicated software. However, this is both a laborious and time-consuming technique. The aim of this study was to evaluate the ability of a visual radiological scale compared with lung CT scan analysis to predict the lung recruitability in ALI/ARDS patients. Methods A whole lung CT scan was performed at 5 and 45 cmH2O airway pressure. For CT scan analysis each lung image was manually outlined and analyzed by a dedicated software. The potentially recruitable lung was defi ned as the proportion of the nonaerated lung tissue in which aeration was restored [1]. For radiological visual scale analysis, two radiologists performed a blinded evaluation of the consolidation/collapsed areas in each lobe by visual inspection [2]. The overall lung change in consolidation/collapsed was obtained by the sum of each lobe and computed as the diff erence between the two conditions. Results Twenty-four ALI/ARDS patients (age 59 \ub1 15 years, BMI 26 \ub1 4 kg/m2, PaO2/FiO2 170 \ub1 60, PEEP 10 \ub1 2 cmH2O) were enrolled. The percentage of potentially recruitable lung was 16.2 \ub1 7.1% and 14.7 \ub1 7.0%, computed by CT scan and by the visual radiological scale, respectively. The mean diff erence between CT scan analysis and visual radiological analysis was 3.3 \ub1 4.6% (median: 2.91, interquartile range: 0.38 to 6.56). The error of the visual method was lower than 5% in 14 patients (58.3%), between 5% and 10% in eight patients (33.3%) and between 10% and 15% in two patients (8.3%). Conclusions The application of a radiological visual scale is able to predict the amount of potentially recruitable lung similarly to those obtained by a dedicated software avoiding the need of manually drawing each lung image. References 1. Gattinoni L, et al.: N Engl J Med 2006, 354:1775-1786. 2. Pierce RJ, et al.: Thorax 1980, 35:773-780

Mild hypoglycemia is independently associated with increased mortality in the critically ill

Introduction: Severe hypoglycemia (blood glucose concentration (BG) < 40 mg/dL) is independently associated with an increased risk of mortality in critically ill patients. The association of milder hypoglycemia (BG < 70 mg/dL) with mortality is less clear.Methods: Prospectively collected data from two observational cohorts in the USA and in The Netherlands, and from the prospective GLUCONTROL trial were analyzed. Hospital mortality was the primary endpoint.Results: We analyzed data from 6,240 patients: 3,263 admitted to Stamford Hospital (ST), 2,063 admitted to three institutions in The Netherlands (NL) and 914 who participated in the GLUCONTROL trial (GL). The percentage of patients with hypoglycemia varied from 18% to 65% among the different cohorts. Patients with hypoglycemia experienced higher mortality than did those without hypoglycemia even after stratification by severity of illness, diagnostic category, diabetic status, mean BG during intensive care unit (ICU) admission and coefficient of variation (CV) as a reflection of glycemic variability. The relative risk (RR, 95% confidence interval) of mortality associated with minimum BG < 40, 40 to 54 and 55 to 69 mg/dL compared to patients with minimum BG 80 to 109 mg/dL was 3.55 (3.02 to 4.17), 2.70 (2.31 to 3.14) and 2.18 (1.87 to 2.53), respectively (all P < 0.0001). The RR of mortality associated with any hypoglycemia < 70 mg/dL was 3.28 (2.78 to 3.87) (P < 0.0001), 1.30 (1.12 to 1.50) (P = 0.0005) and 2.11 (1.62 to 2.74) (P < 0.0001) for the ST, NL and GL cohorts, respectively. Multivariate regression analysis demonstrated that minimum BG < 70 mg/dL, 40 to 69 mg/dL and < 40 mg/dL were independently associated with increased risk of mortality for the entire cohort of 6,240 patients (odds ratio (OR) (95% confidence interval (CI)) 1.78 (1.39 to 2.27) P < 0.0001), 1.29 (1.11 to 1.51) P = 0.0011 and 1.87 (1.46 to 2.40) P < 0.0001) respectively.Conclusions: Mild hypoglycemia was associated with a significantly increased risk of mortality in an international cohort of critically ill patients. Efforts to reduce the occurrence of hypoglycemia in critically ill patients may reduce mortality. © 2011 Krinsley et al. licensee BioMed Central Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Cardiac cycle efficiency as prognostic index in ICUs

We implement a beam steering system based on a directly-modulated unseeded R-SOA, allowing the distribution of 2.4 GHz 64QAM OFDMA signals with 2048-subcarriers satisfying IEEE 802.16e specifications

Anemia profile in critical septic patients hospitalized in the ICU

This article is part of the supplement: 31st International Symposium on Intensive Care and Emergency MedicineThe aim was to describe the anemia profile of medical or surgical patients with severe sepsis or septic shock in the ICU, assessing severity scale, length of stay and mortality. The prevalence of microcytic anemia is more than one-half of our septic patients. There are iron metabolism disorders without significant differences between medical and surgical patients. Transferrin, a protein related to malnutrition, inflammatory response and organ dysfunction, is significantly lower in the most severe patients with higher organ dysfunction scores.Ye