Many hospitalists incorporate point‐of‐care ultrasound (POCUS) into their daily practice to answer specific diagnostic questions or to guide performance of invasive bedside procedures. However, standards for hospitalists in POCUS training and assessment are not yet established. Most internal medicine residency training programs, the major pipeline for incoming hospitalists, have only recently begun to incorporate POCUS in their curricula. The purpose of this document is to inform a broad audience on what POCUS is and how hospitalists are using it. This document is intended to provide guidance for the hospitalists who use POCUS and administrators who oversee its use. We discuss POCUS 1) applications, 2) training, 3) assessments, and 4) program management. Practicing hospitalists must continue to collaborate with their local credentialing bodies to outline requirements for POCUS use. Hospitalists should be integrally involved in decision‐making processes surrounding POCUS program management.

Ab initio quantum chemical calculations for the molecular dissociation channel of acetaldehyde are reported. The enthalpy change for the dissociation of acetaldehyde into methane and carbon monoxide was calculated to be exoergic by 1.7 kcal/mol. The transition state for this unimolecular dissociation, confirmed by normal mode analysis, was found to have an activation energy of 85.3 kcal/mol. Experimental measurements are reported for the vibrational and rotational state distribution of the CO product. No vϭ1 CO is found and the rotational temperature is 1300 Ϯ90 K. The reaction coordinate at the transition state implies that the CO product is vibrationally cold and rotationally hot. This conclusion, which requires quantum dynamics calculations to confirm definitively, does agree with and aids in explaining the experimental results.

The reaction of O(3P) atoms with CH3 radicals is shown to produce CO (in addition to the major product CH2O) which is detected by laser induced fluorescence. The rotational and vibrational temperatures of the CO product are about 2000 K. The results are explained by the assumption that the reaction takes place mainly by an indirect mechanism in which a methoxyl radical is formed and then dissociates unimolecularly.

The HCO product of the reaction of O(3P) with ethene has been detected by cavity ring-down spectroscopy using its A−X transition. For propene a somewhat smaller yield of HCO was obtained but the overall rate constant is much larger. The yield of HCO in this reaction is quite small (∼0.05). Moreover, a large number of other alkenes were tried with negative results. The failure of the 1,2 H atom shift followed by breaking the 1,2 bond implies that the unimolecular decomposition has found a more favorable channel. The proposed mechanism is as follows. For an alkene of the form RCH2CHCH2 the first step is attachment of the O(3P) to the terminal carbon atom, C1. Then, intersystem crossing occurs and finally a H atom shifts from C3 to C2 and not from C1 to C2. In this way a molecule of formaldehyde and an alkene shorter by one carbon atom are formed.

The photodissociation spectroscopy of MgCH 4 ϩ has been studied in a reflectron time-of-flight mass spectrometer. MgCH 4 ϩ molecular absorption bands are observed to the red of the Mg ϩ (3 2 P J ←3 2 S 1/2 ) atomic ion resonance lines. The photofragmentation action spectrum consists of a broad structureless continuum ranging from 310 nm to 342 nm, and peaking near 325 nm. In this spectral region, both the nonreactive ͑Mg ϩ ͒, and two reactive fragmentation products ͑MgH ϩ and MgCH 3 ϩ ͒ are observed, all with similar action spectra. The product branching is independent of wavelength, Mg ϩ :MgCH 3 ϩ :MgH ϩ ϳ60:33:7. The absorption is assigned to the transition (1 2 E←1 2 A 1 ) in C 3v symmetry ͑with 3 coordination͒, followed by a geometrical relaxation of the complex toward states of 2 B 1 and 2 B 2 symmetry in C 2v geometry ͑with 2 coordination͒.Dissociation requires a nonadiabatic transition to the ground electronic surface. Analysis of broadening in the photofragment flight time profile shows the nonreactive Mg ϩ product angular distribution to be isotropic, with an average translational energy release which increases slightly from E t ϳ370Ϯ150 cm Ϫ1 at 332.5 nm to E t ϳ520Ϯ180 cm Ϫ1 at 315 nm. These values are less than 2% of the available energy and are well below statistical expectations. Analogous experiments on MgCD 4 ϩ show the kinetic energy release in the nonreactive channel to be significantly larger for the CD 4 case, ranging from E t ϳ540Ϯ180 cm Ϫ1 at 332.5 nm to E t ϳ830Ϯ200 cm Ϫ1 . These results clearly demonstrate that the dissociation is nonstatistical. Preliminary ab initio potential surface calculations suggest a possible dynamical mechanism to explain these unusual results.

Objectives-To develop a consensus statement on the use of lung ultrasound (LUS) in the assessment of symptomatic general medical inpatients with known or suspected coronavirus disease 2019 .Methods-Our LUS expert panel consisted of 14 multidisciplinary international experts. Experts voted in 3 rounds on the strength of 26 recommendations as "strong," "weak," or "do not recommend." For recommendations that reached consensus for do not recommend, a fourth round was conducted to determine the strength of those recommendations, with 2 additional recommendations considered.Results-Of the 26 recommendations, experts reached consensus on 6 in the first round, 13 in the second, and 7 in the third. Four recommendations were removed because of redundancy. In the fourth round, experts considered 4 recommendations that reached consensus for do not recommend and 2 additional scenarios; consensus was reached for 4 of these. Our final recommendations consist of 24 consensus statements; for 2 of these, the strength of the recommendations did not reach consensus.Conclusions-In symptomatic medical inpatients with known or suspected COVID-19, we recommend the use of LUS to: (1) support the diagnosis of pneumonitis but not diagnose COVID-19, (2) rule out concerning ultrasound features, (3) monitor patients with a change in the clinical status, and (4) avoid unnecessary additional imaging for patients whose pretest probability of an alternative or superimposed diagnosis is low. We do not recommend the use of LUS to guide admission and discharge decisions. We do not recommend routine serial LUS in patients without a change in their clinical condition.

We have studied the structure and dissociation dynamics of the weakly bound bimolecular complex Al+(C2H4) by photodissociation spectroscopy in the 216–320 nm spectral region. Experimental studies are supported by ab initio electronic structure calculations of the ground and low-lying excited states of the complex. Al+ is the dominant photofragment observed throughout the absorption profile. C2H4+ charge transfer product is also observed for shorter photolysis wavelengths, λ<252 nm. The Al+–C2H4 bond dissociation energy is measured as D0=0.37±0.15 eV. Three molecular absorption bands are observed and assigned to the transitions (2 1A1,1 1B1,1 1B2←1 1A1) in C2v equilibrium complex geometry. The excited states are of predominantly charge-transfer character correlating with the product channel Al(3s23p)+(C2H4)+. The 2 1A1 and 1 1B2←1 1A1 absorption bands appear broad and structureless. This observation is consistent with ab initio results that suggest a pathway for rapid nonadiabatic dissociation through a 1 1B2–1 1A1 surface crossing facilitated by a stretch in the C–C bond of ethylene. In contrast the 1 1B1←1 1A1 molecular band shows significant vibrational structure. Spectroscopic analysis yields a band origin (000=40 042 cm−1) and corresponding vibrational mode frequencies for the 1 1B1 excited state. The observed modes have been assigned to the intermolecular Al–C2H4 stretch of a1 symmetry (ν2=230 cm−1), the Al–C2H4 out-of-plane wag with b1-symmetry (ν3=328 cm−1), and two intramolecular ethylene modes of a1 symmetry at 1264 and 1521 cm−1. The assignment for these higher frequency ethylene modes is not conclusive.

Background Point-of-care ultrasound (POCUS) is rapidly becoming ubiquitous across healthcare specialties. This is due to several factors including its portability, immediacy of results to guide clinical decision-making, and lack of radiation exposure to patients. The recent growth of handheld ultrasound devices has improved access to ultrasound for many clinicians. Few studies have directly compared different handheld ultrasound devices among themselves or to cart-based ultrasound machines. We conducted a prospective observational study comparing four common handheld ultrasound devices for ease of use, image quality, and overall satisfaction. Twenty-four POCUS experts utilized four handheld devices (Butterfly iQ+™ by Butterfly Network Inc., Kosmos™ by EchoNous, Vscan Air™ by General Electric, and Lumify™ by Philips Healthcare) to obtain three ultrasound views on the same standardized patients using high- and low-frequency probes. Results Data were collected from 24 POCUS experts using all 4 handheld devices. No single ultrasound device was superior in all categories. For overall ease of use, the Vscan Air™ was rated highest, followed by the Lumify™. For overall image quality, Lumify™ was rated highest, followed by Kosmos™. The Lumify™ device was rated highest for overall satisfaction, while the Vscan Air™ was rated as the most likely to be purchased personally and carried in one’s coat pocket. The top 5 characteristics of handheld ultrasound devices rated as being “very important” were image quality, ease of use, portability, total costs, and availability of different probes. Conclusions In a comparison of four common handheld ultrasound devices in the United States, no single handheld ultrasound device was perceived to have all desired characteristics. POCUS experts rated the Lumify™ highest for image quality and Vscan Air™ highest for ease of use. Overall satisfaction was highest with the Lumify™ device, while the most likely to be purchased as a pocket device was the Vscan Air™. Image quality was felt to be the most important characteristic in evaluating handheld ultrasound devices.