Qualifying the difficulty of embryo transfer with a visual analogue scale and assessing its impact on IVF outcomes.

The aim of this study was to determine whether a continuous visual analogue scale (VAS) is a reliable tool to grade embryo transfer (ET) difficulty when assessing IVF outcomes. No standardized grading system exists for reporting ET 'difficulty' which is typically recorded in descriptive terms. Clinicians performing 188 fresh single ETs between November 2014 and May 2016 also recorded a VAS score (0-100). Embryo transfers were stratified into three levels of ET 'difficulty': (A) 'easy' - no resistance; (B) 'medium' - resistance overcome by advancing the catheter's outer sheath; and (C) 'difficult' - a malleable stylet was required to overcome resistance; and these compared to the VAS scores. Clinical pregnancy and live birth rates were the primary outcomes. VAS scores were categorized into four incremental groupings according to the 25th, 50th and 75th percentiles (Groups 1-4) for analysis. No significant relationship (p > 0.05) was seen in clinical pregnancy or live birth rates in either the standard difficulty or the VAS groupings. The median VAS scores in Groups A-C increased as difficulty increased, but the interquartile ranges overlap with wide clinician variation, suggesting the VAS is not itself a reliable enough tool to record ET difficulty in isolation.

A device for sampling arterialized earlobe blood in austere environments.

INTRODUCTION: There is currently no effective method of measuring arterial blood gas tensions in austere environments such as in space or at high altitude. An alternative to direct arterial measurement is the sampling of arterialized earlobe blood, an accurate technique that has been in use in clinical medicine and physiology for more than 50 yr. We, therefore, developed an earlobe arterialized blood (EAB) collector for practical use in extreme environments. METHODS: The results from the EAB collector were compared with simultaneous samples of blood drawn from the radial artery. Six healthy subjects breathed a gas mixture of 12.8% O2 in N2 during 15 min of 8 degree head-down tilt. The blood samples were analyzed immediately. RESULTS: The mean differences in Po2 between arterialized earlobe and radial artery samples were 0.25 +/- 1.25 mmHg for Po2 and 1.0 +/- 0.75 mmHg for Pco2; neither difference was significant. There was no difference between the pH values obtained by the two techniques. CONCLUSION: This study suggests that arterialized blood sampled from the earlobe using the EAB collector may provide sufficiently accurate measurements of the Po2, Pco2 and pH of arterial blood for clinical or research use in extreme environments.

Intensity-dependent tolerance to exercise after attaining V(O2) max in humans.

The tolerable duration of high-intensity, constant-load cycle ergometry is a hyperbolic function of power, with an asymptote termed critical power (CP) and a curvature constant (W') with units of work. It has been suggested that continued exercise after exhaustion may only be performed below CP, where predominantly aerobic energy transfer can occur and W' can be partially replenished. To test this hypothesis, six volunteers each performed cycle-ergometer exercise with breath-by-breath determination of ventilatory and pulmonary gas exchange variables. Initially, four exercise tests to exhaustion were made: 1). a ramp-incremental and 2). three high-intensity constant-load bouts at different work rates, to estimate lactate (theta(L)) and CP thresholds, W', and maximum oxygen uptake (Vo2 max). Subsequently, subjects cycled to the limit of tolerance (for approximately 360 s) on three occasions, each followed by a work rate reduction to 1). 110% CP, 2). 90% CP, and 3). 80% theta(L) for a 20-min target. W' averaged 20.9 +/- 2.35 kJ or 246 +/- 30 J/kg. After initial fatigue, 110% CP was tolerated for only 30 +/- 12 s. Each subject completed 20 min at 80% theta(L), but only two sustained 20 min at 90% CP; the remaining four subjects fatigued at 577 +/- 306 s, with oxygen consumption at 89 +/- 8% Vo2 max. The results support the suggestion that replenishing W' after fatigue necessitates a sub-CP work rate. The variation in subjects' responses during 90% CP was unexpected but consistent with mechanisms such as reduced CP consequent to prior high-intensity exercise, variation in lactate handling, and/or regional depletion of energy substrates, e.g., muscle glycogen.