Renal point-of-care ultrasound performed by ED staff with limited training and 30-day outcomes in patients with renal colic.

BACKGROUND AND AIM: Emergency Department (ED) renal point-of-care ultrasound (PoCUS) in renal colic by accredited specialists has good prognostic value. This may not be generalizable to under-resourced EDs. We investigated PoCUS in renal colic in our ED with lesser training. METHODS: We performed a single-centre health records review of adult ED patients with renal colic and PoCUS. Patients were managed by a non-ED specialist/resident doctor with no POCUS accreditation in consultation with an attending. These doctors attended a 3.5-h training session conducted by accredited attendings to examine hydronephrosis. They needed to verify their PoCUS findings with an attending during the first two weeks of their six-month posting before performing it independently. The primary outcome was 30-day urological procedures in hydronephrotic vs. non-hydronephrotic groups. Secondary outcomes were the distribution of primary outcome with grades of hydronephrosis, 30-day ED nephrolithiasis-related reattendances in hydronephrotic vs. non-hydronephrotic groups and its distribution with grades of hydronephrosis. We compared outcomes using Fisher's exact test. We also reported crude odds ratio (COR) and 95% CI of primary outcome between hydronephrotic vs. non-hydronephrotic groups. p values ≤ 0.05 were significant. RESULTS: We recruited 651 patients; 160 (24.6%) without and 491 (75.4%) with hydronephrosis. Rates of grades of hydronephrosis were: mild (76.6%), moderate (13.8%), severe (1.2%) and undifferentiated (8.4%). There was a difference in 30-day urological procedures (rates [95% CI]) in hydronephrotic vs. non-hydronephrotic groups, 11.2 [8.7-14.0]% vs. 2.5 [1.0-6.3]%; p < 0.001; COR (95% CI) 4.9 (1.8-13.8); p = 0.002. Increasing 30-day urological procedural rates were associated with increasing grade of hydronephrosis [no: 2.5%, mild: 7.7%, moderate: 23.5%, severe: 67.0% and undifferentiated: 14.6%; p < 0.001]. No differences occurred in other secondary outcomes. CONCLUSIONS: Renal PoCUS could be performed by non-ED specialist/resident doctors to identify patients without hydronephrosis who rarely required urological intervention. Hydronephrotic patients could benefit from further risk stratification.

ABSTRAIT: CONTEXTE ET OBJECTIF: L'échographie rénale au point de soin (PoCUS) dans les coliques rénales par des spécialistes agréés a une bonne valeur pronostique. Cela peut ne pas être généralisable aux SU sous-financés. Nous avons étudié PoCUS dans les coliques rénales dans notre DE avec une formation moindre. MéTHODES: Nous avons effectué un examen des dossiers médicaux d'un seul centre des patients adultes atteints de coliques rénales et de PoCUS. Les patients étaient pris en charge par un médecin résident/spécialiste non-membre de la DG sans accréditation POCUS en consultation avec un médecin traitant. Ces médecins ont assisté à une séance de formation de 3,5 heures menée par des titulaires accrédités pour examiner l'hydronéphrose. Ils devaient vérifier leurs résultats PoCUS auprès d'un assistant pendant les deux premières semaines de leur affectation de six mois avant de l'effectuer de manière indépendante. Le critère de jugement principal était des procédures urologiques de 30 jours dans les groupes hydronéphrotiques vs non-hydronephrotiques. Les critères de jugement secondaires étaient la distribution du critère de jugement primaire avec les grades d'hydronéphrose, les reattendances liées à la néphrose ED de 30 jours dans les groupes hydronéphrotiques vs non hydronéphrotiques et sa distribution avec les grades d'hydronéphrose. Nous avons comparé les résultats en utilisant le test exact de Fisher. Nous avons également signalé un rapport de cotes brut (RC) et un IC à 95 % du critère de jugement principal entre les groupes hydronéphrotiques et non hydronéphrotiques. Les valeurs de P 0,05 étaient significatives. RéSULTATS: Nous avons recruté 651 patients; 160 (24,6%) sans et 491 (75,4%) avec hydronéphrose. Les taux d'hydronéphrose étaient les suivants : légère (76,6 %), modérée (13,8 %), sévère (1,2 %) et indifférenciée (8,4 %). Il y avait une différence dans les interventions urologiques de 30 jours (taux [IC à 95 %]) dans les groupes hydronéphrotiques par rapport aux groupes non-hydronephrotiques, 11,2 [8,7-14,0] % contre 2,5 [1,0-6,3]%; p < 0,001; RCC (IC à 95 %) 4,9 (1,8-13,8); p = 0,002. L'augmentation des taux de procédures urologiques de 30 jours était associée à l'augmentation du grade d'hydronéphrose [non : 2,5%, léger : 7,7%, modéré : 23,5%, sévère : 67,0% et indifférencié : 14,6%; p < 0,001]. Aucune différence n'est survenue dans les autres critères de jugement secondaires. CONCLUSIONS: La PoCUS rénale pourrait être réalisée par des médecins non spécialistes/résidents de la D pour identifier les patients sans hydronéphrose qui ont rarement nécessité une intervention urologique. Les patients hydronéphrotiques pourraient bénéficier d'une meilleure stratification des risques.

Temporal model for quasi-phase matching in high-order harmonic generation.

We present a model for quasi-phase matching (QPM) in high-order harmonic generation (HHG). Using a one-dimensional description, we analyze the time-dependent, ultrafast wave-vector balance to calculate the on-axis harmonic output versus time, from which we obtain the output pulse energy. Considering, as an example, periodically patterned argon gas, as may be provided with a grid in a cluster jet, we calculate the harmonic output during different time intervals within the drive laser pulse duration. We find that identifying a suitable single spatial period is not straightforward due to the complex and ultrafast plasma dynamics that underlies HHG at increased intensities. The maximum on-axis harmonic pulse energy is obtained when choosing the QPM period to phase match HHG at the leading edge of the drive laser pulse.

Spectral control of high-harmonic generation via drive laser pulse shaping in a wide-diameter capillary.

We experimentally investigate spectral control of high-harmonic generation in a wide-diameter (508 µm) capillary that allows using significantly lower gas pressures coupled with elevated drive laser energies to achieve higher harmonic energies. Using phase shaping to change the linear chirp of the drive laser pulses, we observe wavelength tuning of the high-harmonic output to both larger and smaller values. Comparing tuning via the gas pressure with the amount of blue shift in the transmitted drive laser spectrum, we conclude that both adiabatic and non-adiabatic effects cause pulse-shaping induced tuning of high harmonics. We obtain a fractional wavelength tuning, Δλ/λ, in the range from -0.007 to + 0.01, which is comparable to what is achieved with standard capillaries of smaller diameter and higher pressures.

Synthesis of well dispersed polymer grafted metal-organic framework nanoparticles.

Novel polymer grafted metal-organic framework (MOF) nanoparticles were synthesized. The formed core/shell nanoparticles exhibit outstanding water dispersity and pH sensitivity, and show their catalytic effect for the reduction reaction of 4-nitrophenol (NP) to 4-aminophenol (AP) when loaded with Pd(0) catalyst.

Single-shot fluctuations in waveguided high-harmonic generation.

For exploring the application potential of coherent soft x-ray (SXR) and extreme ultraviolet radiation (XUV) provided by high-harmonic generation, it is important to characterize the central output parameters. Of specific importance are pulse-to-pulse (shot-to-shot) fluctuations of the high-harmonic output energy, fluctuations of the direction of the emission (pointing instabilities), and fluctuations of the beam divergence and shape that reduce the spatial coherence. We present the first single-shot measurements of waveguided high-harmonic generation in a waveguided (capillary-based) geometry. Using a capillary waveguide filled with Argon gas as the nonlinear medium, we provide the first characterization of shot-to-shot fluctuations of the pulse energy, of the divergence and of the beam pointing. We record the strength of these fluctuations vs. two basic input parameters, which are the drive laser pulse energy and the gas pressure in the capillary waveguide. In correlation measurements between single-shot drive laser beam profiles and single-shot high-harmonic beam profiles we prove the absence of drive laser beam-pointing-induced fluctuations in the high-harmonic output. We attribute the main source of high-harmonic fluctuations to ionization-induced nonlinear mode mixing during propagation of the drive laser pulse inside the capillary waveguide.

Fabrication and characterization of free-standing, high-line-density transmission gratings for the vacuum UV to soft X-ray range.

We present state-of-the-art high resolution transmission gratings, applicable for spectroscopy in the vacuum ultraviolet (VUV) and the soft X-ray (SRX) wavelength range, fabricated with a novel process using ultraviolet based nano imprint lithography (UV-NIL). Free-standing, high-line-density gratings with up to 10,000 lines per mm and various space-to-period ratios were fabricated. An optical characterization of the gratings was carried out in the range from 17 to 34 nm wavelength using high-harmonic generation in a capillary waveguide filled with Ne, and around 13.5 nm wavelength (from 10 to 17 nm) using a Xenon discharge plasma.