Citations

PurposeIn normal eyes, a fixed relationship between anterior and posterior corneal astigmatism is assumed, especially for lens power calculations. This study assessed the association between anterior and posterior corneal astigmatism and thickness.MethodsNormal corneas were examined by slit‐lamp microscopy and Scheimpflug imaging. The differences between vertical and horizontal thicknesses at 4‐mm and 6‐mm‐diameters were calculated. Anterior and posterior astigmatism were calculated as the difference between steep and flat powers based on the corresponding radii of curvature and refractive indices. Comparisons and significances of correlations were assessed by using generalized estimating equation models.ResultsFifty‐four subjects (101 corneas) aged 18–80 years were included. Peripheral corneas were thicker vertically than horizontally (p < 0.001) at 4 mm by 13.4 ± 9.4 µm (mean ± standard deviation) and at 6 mm by 8.6 ± 4.8 µm. Anterior corneal astigmatism was 1.08 ± 0.57 D and was aligned vertically (73%), horizontally (6%), or obliquely (21%). Posterior corneal astigmatism was −0.31 ± 0.13 D and was aligned vertically (94%) or obliquely (6%). Anterior and posterior astigmatism were correlated in eyes with vertical anterior astigmatism (r = 0.65; p < 0.001), but not in eyes with oblique or horizontal anterior astigmatism. The difference between vertical and horizontal corneal thickness correlated with posterior astigmatism at 4 mm (r = −0.58; p < 0.001) and at 6 mm (r = −0.61; p < 0.001).ConclusionsThe posterior cornea is normally ellipsoid in shape with a steep vertical meridian that corresponds to the cornea being thicker in the vertical paracentral region. Understanding the normal relationship between anterior and posterior corneal surfaces is important when assessing the same in corneal diseases.

Exercise after surgery significantly improves metabolic benefits of gastric bypass.

Background: Previous studies have demonstrated optimized diagnostic accuracy in utilizing higher antiheparin–platelet factor 4 (PF4) enzyme-linked immunosorbent assay (ELISA) optical density (OD) thresholds for diagnosing heparin-induced thrombocytopenia (HIT). We describe the incidence of positive serotonin release assay (SRA) results, as well as performance characteristics, for antiheparin–PF4 ELISA thresholds ≥0.4, ≥0.8, and ≥1.0 OD units in the diagnosis of HIT at our institution. Methods: Following institutional review board approval, we conducted a single-center retrospective chart review on adult inpatients with a differential diagnosis of HIT evaluated by both antiheparin–PF4 ELISA and SRA from 2012 to 2014. The major endpoints were to assess incidence of positive SRA results, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy at antiheparin–PF4 ELISA values ≥0.4 OD units when compared to values ≥0.8 and ≥1.0 OD units. Clinical characteristics, including demographics, laboratory values, clinical and safety outcomes, length of stay, and mortality, were collected. Results: A total of 140 patients with 140 antiheparin–PF4 ELISA and SRA values were evaluated, of which 23 patients were SRA positive (16.4%) and 117 patients were SRA negative (83.6%). We identified a sensitivity of 91.3% versus 82.6% and 73.9%, specificity of 61.5% versus 87.2% and 91.5%, PPV of 31.8% versus 55.9% and 63.0%, NPV of 97.3% versus 96.2% and 94.7%, and accuracy of 66.4% versus 86.4% and 88.6% at antiheparin–PF4 ELISA thresholds ≥0.4, ≥0.8, and ≥1.0 OD units, respectively. Conclusion: Our study suggests an increased antiheparin–PF4 ELISA threshold of 0.8 or 1.0 OD units enhances specificity, PPV, and accuracy while maintaining NPV with decreased sensitivity.

The effect of fish consumption on blood pressure is controversial. The authors measured blood pressure and calculated oily fish servings per week in 677 community‐dwellers aged 40 years and older living in rural coastal Ecuador. Using regression models with linear splines, the authors evaluated whether dietary fish intake was related to blood pressure levels, after adjusting for relevant confounders. Mean oily fish consumption was 9.1±5.6 servings per week. There was a nonlinear relationship between systolic pressure and fish servings. In the group of individuals consuming up to five servings per week, each serving significantly reduced systolic pressure by 2.3 mm Hg (P=.020). Any extra serving provided no further effects. The study shows an inverse relationship between oily fish consumption and systolic pressure. Currently recommended amounts of dietary oily fish intake per week (1–2 servings) might be insufficient to exert beneficial effects of fish in the control of blood pressure.

Tension pneumothorax is a rare and potentially life-threatening clinical complication. A 43-year-old Caucasian woman with type 1 diabetes mellitus presented with nausea and retching and examination revealed dehydration. Laboratory parameters were consistent with a diagnosis of diabetic ketoacidosis, which responded to therapy. Suddenly, 30 hours later, she developed cardiorespiratory compromise due to a tension pneumothorax. After emergent decompression and catheter placement, computerized tomographic scan of the chest demonstrated esophageal-pleural fistula confirming Boerhaave syndrome as the etiology for the pneumothorax. The patient underwent emergent esophagectomy with pleural washout with a subsequent gastric pull-up surgery. Boerhaave syndrome frequently presents atypically with chest pain, dyspnea, and nausea. It communicates with the left pleural space in 80% to 90% of cases, but <5% of cases involve the right pleural cavity. Unexplained and rapidly progressive pleural effusions have been associated with this entity. Only 4 cases of Boerhaave syndrome causing tension pneumothorax have been reported in the literature so far.

Background: Patients with patellar instability and a tibial tubercle–trochlear groove (TT-TG) distance ≥20 mm may be candidates for distal tubercle realignment surgery. Although this variable has proven valuable in predicting recurrent dislocations, it is not individualized to patient size, bony structure, or patellofemoral mechanics. Purpose: To develop a patellar instability ratio (PIR) that predicts the risk of recurrent instability based on the TT-TG distance to patient-specific anatomy. Study Design: Cohort study; Level of evidence, 3. Methods: On magnetic resonance imaging scans of 59 knees with patellar instability, the TT-TG distance, tibial tubercle–posterior cruciate ligament (TT-PCL) distance, sagittal patellar length (PL), sagittal trochlear length (TL), axial patellar width (PW), and axial trochlear width (TW) were calculated by 2 observers in a blinded and randomized fashion. Patients were divided into 2 groups: those with a single dislocation and those with multiple (≥2) dislocations. The ability of the TT-TG and TT-PCL distances as well as the 8 different ratios to predict recurrent instability was assessed by calculating odds ratios (ORs), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each measure. Results: Twelve knees (20%) experienced a single dislocation, while 47 (80%) sustained multiple dislocations. A TT-TG distance ≥20 mm was predictive of recurrent instability, with a sensitivity, specificity, and PPV of 21%, 100%, and 100%, respectively. The OR for TT-TG ≥20 mm was 5.38 ( P = .29), while the highest ORs for recurrent instability were noted for a TT-TG/PW ≥0.4 (OR, 7.37; P = .02) and a TT-TG/TW ≥0.5 (OR, 8.88; P = .04). The sensitivity, specificity, and PPV of a TT-TG/PW ≥0.4 were 62%, 83%, and 94%, respectively, while those of a TT-TG/TW ≥0.5 were 45%, 92%, and 95%, respectively. Conclusion: Two novel PIRs (TT-TG/TW and TT-TG/PW) were identified and found to more effectively predict recurrent instability than the TT-TG distance alone. Each ratio takes into account patient-specific anatomy and can be measured in an accurate and reliable fashion by clinicians. These PIRs are a step toward overcoming some of the limitations of using the TT-TG distance in isolation. Further investigation into the clinical applications and utility of the TT-TG/TW is warranted.