Low oxygen affinity variant haemoglobin in an elderly woman presenting with low oxygen saturation

An asymptomatic 81-year-old woman was referred by her general practitioner regarding a pulse-oximetry oxygen saturation (SpO2) of 74%. An arterial blood gas analysis (ABG) on air showed PaO2 12.9 kPa, oxygen saturation 80%, with normal pH, PaCO2, methaemoglobin and carboxyhaemoglobin levels. After a normal chest x-ray, tinzaparin was administered empirically for possible occult pulmonary embolus. This diagnosis was subsequently excluded with an unremarkable computed tomography pulmonary angiogram (CTPA). She was further investigated as an out patient. DNA globin-gene analysis identified a variant haemoglobin revealed to be haemoglobin Saint Mande (HbSM). Following reassurance regarding the benign nature of her condition, she has remained well

Abnormal ventilation-perfusion scan is associated with pulmonary hypertension in sickle cell adults

Pulmonary hypertension (PH) in adults with sickle cell disease (SCD) is associated with early mortality. Chronic thromboembolic PH (CTEPH) is an important complication and contributor to PH in SCD but is likely underappreciated. Guidelines recommend ventilation-perfusion (V/Q) scintigraphy as the imaging modality of choice to exclude CTEPH. Data on V/Q scanning are limited in SCD. Our objective was to compare the performance of V/Q scanning with that of CT pulmonary angiography (CTPA) and to report clinical outcomes associated with abnormal V/Q findings. Methods: Laboratory data, echocardiography, 6-min-walk testing, V/Q scanning, CTPA, and right heart catheterization (RHC) were prospectively obtained. High-probability and intermediate-probability V/Q findings were considered to be abnormal. Included for analysis were 142 SCD adults (aged 40.1 ± 13.7 y, 83 women, 87% hemoglobin SS) in a stable state enrolled consecutively between March 13, 2002, and June 8, 2017. Results: V/Q results were abnormal in 65 of 142 patients (45.8%). CTPA was positive for pulmonary embolism in 16 of 60 (26.7%). RHC confirmed PH (mean pulmonary artery pressure $ 25 mmHg) in 46 of 64 (71.9%), of whom 34 (73.9%) had abnormal V/Q findings. Among those without PH by RHC (n 5 18), 2 of 18 patients had abnormal V/Q findings. Thirty-three patients had a complete dataset (V/Q scanning, CTPA, and RHC); 29 of 33 had abnormal RHC findings, of whom 26 had abnormal V/Q findings, compared with 11 who had abnormal CTPA findings. There was greater concordance between V/Q findings and RHC (κ-value 5 0.53; P, 0.001) than between CTPA and RHC (κ-value 5 0.13; P 5 0.065). The sensitivity and specificity for V/Q scanning was 89.7% and 75.0%, respectively, whereas CTPA had sensitivity of 37.3% and specificity of 100%. Abnormal V/Q finding swere associated with hemodynamic severity (mean pulmonary artery pressure, 35.2 ± 9.6 vs. 26.9 ± 10.5 mm Hg, P 5 0.002; transpulmonary gradient, 21.5 ± 9.7 vs. 12.16 ± 11 mmHg, P 5 0.005; and pulmonary vascular resistance, 226.5 ± 135 vs. 140.7 ± 123.7 dynesscm −5 , P 5 0.013) and exercise capacity (6-min-walk distance, 382.8 ± 122.3 vs. 442.3 ± 110.6 m, P, 0.010). Thirty-four deaths were observed over 15 y. All-cause mortality was higher in the abnormal-V/Q group (21 [61.8%]) than in the normal-V/Q group (13 [38.2%]) (log-rank test, P 5 0.006; hazard ratio, 2.54). Conclusion: V/Q scanning is superior to CTPA in detecting thrombotic events in SCD. Abnormal V/Q findings are associated with PH, worse hemodynamics, lower functional capacity, and higher mortality. Despite high sensitivity in detecting CTEPH, V/Q scanning is underutilized. We recommend the use of V/Q scanning in the evaluation of dyspnea in adult SCD patients given the important implications toward management

Application of unsaturated shear strength properties in slope stability analysis

It is very important to study applications of unsaturated soil properties in slope stability analysis due to the additional shear strength an unsaturated soil possesses. Shear strength of an unsaturated soil is strongly related to the amount of water in the voids of the soil, and therefore to the matric suction. It is postulated that the shear strength of an unsaturated soil should also bear a relationship to the soil-water characteristic curve. In this thesis, the effect of unsaturated shear strength properties on stability of slopes is investigated by analysing for the stability of hypothetical cut slopes. The effect of the position of water table below the failure surface of hypothetical cut slopes were analysed using Slope/w software for different water table positions for three different cut slope angles. For this work, analyses were done by replacing the cohesion by the apparent cohesion values. Apparent cohesion values were increased by increasing the depth of water table and increasing the effect of negative pore water pressure. Different apparent cohesion values corresponding to the different percentage of negative hydrostatic pressures were utilized. Spreadsheets prepared by a previous research were used to analyse the hypothetical cut slopes by the Modified Janbu’s Method of slices for unsaturated soils. The negative pore water pressure could be directly taken into account in this method, and the Factors of Safety (FOS) derived by this method are compared with the results from SLOPE/W software. Variation of FOS with slope angle and position of water table are investigated. The parametric study done here gives an insight into the problem of landslides. Lowering of the Water Table is been to increase the FOS against sliding failure, as expected