Mesenteric ischemia in the acute care setting.

ABSTRACT: Mesenteric ischemia is a group of disorders requiring prompt identification, supportive care, and treatment. Chronic mesenteric ischemia can develop into acute mesenteric ischemia, which has high mortality. Acute mesenteric ischemia can be occlusive (caused by arterial embolism, arterial thrombosis, or mesenteric venous thrombosis) or nonocclusive, with treatment depending on the underlying cause.

Mesenteric ischemia in the acute care setting.

ABSTRACT: Mesenteric ischemia is a group of disorders requiring prompt identification, supportive care, and treatment. Chronic mesenteric ischemia can develop into acute mesenteric ischemia, which has high mortality. Acute mesenteric ischemia can be occlusive (caused by arterial embolism, arterial thrombosis, or mesenteric venous thrombosis) or nonocclusive, with treatment depending on the underlying cause.

Development and Implementation of an Ultrasound-Guided Peripheral Intravenous Catheter Education Program for Critical Care Nurses.

BACKGROUND: Ultrasound-guided (US-guided) peripheral intravenous (PIV) insertion is a skill used by specially trained nurses for patients with difficult vascular access. It can result in potential complications such as occlusive thrombus, phlebitis, infiltration, and pain. Complications can be prevented or minimized with clinical training to achieve competency. Current research shows that the most effective approach to US-guided PIV training consists of a comprehensive structured educational program that includes didactic, hands-on training and skills application. OBJECTIVES: This study aimed to develop and implement a US-guided PIV education program for critical care nurses. METHODS: Structured education was developed using a step-wise method. Critical care nurse practitioners in the intensive care unit (ICU) developed training materials including hands-on training, ultrasound reference material, and supervised skills application. Afterward, US-guided PIV-trained critical care nurses were enabled to train other nurses in the ICU. RESULTS: The total number of US-guided PIV-trained registered nurses in the ICU increased from 5.8% to 26% of staff, but represents only 20% of those trained at current staffing levels. The percentage of US-guided PIV-trained nightshift/weekend staff increased from 3.9% to 24%, but represents 14% at current staffing levels. One hundred five US-guided PIVs showed a 97% success rate of US-guided PIV placement during an 11-month timeframe, similar to success rates published in the literature that ranged from 86% to 100%. There was 1.9% complication rate for occlusive thrombus, which is below published rates ranging up to 10%. DISCUSSION: Critical care nurse practitioners in the ICU collaborated with vascular nursing and hospital clinical education to successfully develop and implement a US-guided PIV training program to meet patient needs within a growing community facility. The results of the training program yielded similar success and complication rates as those reported in the literature. Ongoing training is essential for program sustainability. CONCLUSIONS: Critical care nurse practitioners training registered nurses in US-guided PIV placement is an effective approach to training. Critical care nurses trained in US-guided PIV insertion can safely and effectively train other critical care nurses in US-guided PIV insertion.

Preventing Catheter-Associated Urinary Tract Infections with Incontinence Management Alternatives: PureWick and Condom Catheter.

Catheter-associated urinary tract infections (CAUTI) have a high financial and human impact on patients and society at large, making CAUTI prevention strategies essential. A shift has occurred where nurses play an increased role in infection prevention. Nurses promote staff and patient education on CAUTI prevention, identification of appropriate urinary incontinence management, and implementation of bundles and patient care strategies to minimize complications from urinary incontinence management. Because they understand the severity of CAUTI and current recommendations, nurses at the bedside are in the best position to identify appropriate indications of indwelling urinary catheters and external urine collection devices for patients.

Nonspecialty Nurse Education: Evaluation of the Oncology Intensives Initiative, an Oncology Curriculum to Improve Patient Care

BACKGROUND: A community hospital combined its medical and surgical patients with cancer on one unit, which resulted in nurses not trained in oncology caring for this patient population. OBJECTIVES: The Oncology Intensives Initiative (ONCii) involved the (a) design and implementation of a daylong didactic boot camp class and a four-hour simulation session and (b) the examination of nurses' worries, attitudes, self-efficacy, and perception of interdisciplinary teamwork. METHODS: A two-group, pre-/post-test design was implemented. Group 1 consisted of nurses who attended the didactic boot camp classes alone, whereas group 2 was comprised of nurses who attended the didactic boot camp classes and the simulation sessions. FINDINGS: Results of data analysis showed a decrease in worries and an increase in positive attitudes toward chemotherapy administration in both groups, as well as an increase in self-efficacy among members of group 2.

Characterization of a cyanobacterial-like uptake [NiFe] hydrogenase: EPR and FTIR spectroscopic studies of the enzyme from Acidithiobacillus ferrooxidans.

Electron paramagnetic resonance (EPR) and Fourier transform IR studies on the soluble hydrogenase from Acidithiobacillus ferrooxidans are presented. In addition, detailed sequence analyses of the two subunits of the enzyme have been performed. They show that the enzyme belongs to a group of uptake [NiFe] hydrogenases typical for Cyanobacteria. The sequences have also a close relationship to those of the H(2)-sensor proteins, but clearly differ from those of standard [NiFe] hydrogenases. It is concluded that the structure of the catalytic centre is similar, but not identical, to that of known [NiFe] hydrogenases. The active site in the majority of oxidized enzyme molecules, 97% in cells and more than 50% in the purified enzyme, is EPR-silent. Upon contact with H(2) these sites remain EPR-silent and show only a limited IR response. Oxidized enzyme molecules with an EPR-detectable active site show a Ni(r)*-like EPR signal which is light-sensitive at cryogenic temperatures. This is a novelty in the field of [NiFe] hydrogenases. Reaction with H(2) converts these active sites to the well-known Ni(a)-C* state. Illumination below 160 K transforms this state into the Ni(a)-L* state. The reversal, in the dark at 200 K, proceeds via an intermediate Ni EPR signal only observed with the H(2)-sensor protein from Ralstonia eutropha. The EPR-silent active sites in as-isolated and H(2)-treated enzyme are also light-sensitive as observed by IR spectra at cryogenic temperatures. The possible origin of the light sensitivity is discussed. This study represents the first spectral characterization of an enzyme of the group of cyanobacterial uptake hydrogenases.

Experimental and density functional theoretical investigations of linkage isomerism in six-coordinate FeNO(6) iron porphyrins with axial nitrosyl and nitro ligands.

A critical component of the biological activity of NO and nitrite involves their coordination to the iron center in heme proteins. Irradiation (330 < lambda < 500 nm) of the nitrosyl-nitro compound (TPP)Fe(NO)(NO(2)) (TPP = tetraphenylporphyrinato dianion) at 11 K results in changes in the IR spectrum associated with both nitro-to-nitrito and nitrosyl-to-isonitrosyl linkage isomerism. Only the nitro-to-nitrito linkage isomer is obtained at 200 K, indicating that the isonitrosyl linkage isomer is less stable than the nitrito linkage isomer. DFT calculations reveal two ground-state conformations of (porphine)Fe(NO)(NO(2)) that differ in the relative axial ligand orientations (i.e., GS parallel and GS perpendicular). In both conformations, the FeNO group is bent (156.4 degrees for GS parallel, 159.8 degrees for GS perpendicular) for this formally {FeNO}(6) compound. Three conformations of the nitrosyl-nitrito isomer (porphine)Fe(NO)(ONO) (MSa parallel, MSa perpendicular, and MSa(L)) and two conformations of the isonitrosyl-nitro isomer (porphine)Fe(ON)(NO(2)) (MSb parallel and MSb perpendicular) are identified, as are three conformations of the double-linkage isomer (porphine)Fe(ON)(ONO) (MSc parallel, MSc perpendicular, MSc(L)). Only 2 of the 10 optimized geometries contain near-linear FeNO (MSa(L)) and FeON (MSc(L)) bonds. The energies of the ground-state and isomeric structures increase in the order GS < MSa < MSb < MSc. Vibrational frequencies for all of the linkage isomers have been calculated, and the theoretical gas-phase absorption spectrum of (porphine)Fe(NO)(NO(2)) has been analyzed to obtain information on the electronic transitions responsible for the linkage isomerization. Comparison of the experimental and theoretical IR spectra does not provide evidence for the existence of a double linkage isomer of (TPP)Fe(NO)(NO(2)).

Photoinduced oxygen transfer and double-linkage isomerism in a cis-(NO)(NO2) transition-metal complex by photocrystallography, FT-IR spectroscopy and DFT calculations.

Photocrystallographic experiments show that laser exposure of crystals of [Ru(bpy)2(NO)(NO2)](PF6)2 at 90 K produces a double isonitrosyl-nitrito linkage isomer and provide the detailed geometry of the metastable species generated. The analysis indicates that the isomerization is accomplished through an intramolecular redox reaction involving oxygen transfer from the nitro to the nitrosyl group. At 200 K only a single (nitrito) linkage isomer is formed with a U-shaped conformation of the nitrito group rather than the Z conformation observed at 90 K. A mechanism for the isomerization is proposed based on the crystallographic results and FTIR data collected at low temperatures during the isomerization process. The study presents the first structural evidence for double linkage isomerization in transition-metal complexes.

Single- and double-linkage isomerism in a six-coordinate iron porphyrin containing nitrosyl and nitro ligands.

Density Functional theoretical calculations confirm the experimental observation that the low-temperature photolysis of (TPP)Fe(NO)(NO2) (as a KBr pellet) results in the generation of linkage isomers involving the axial NO and NO2 groups and suggest the possible formation of the double linkage isomer (TPP)Fe(ON)(ONO). The energy difference between the ground state (porphine)Fe(NO)(NO2) and the double-linkage isomer (porphine)Fe(ON)(ONO) is 1.57 eV, which is comparable to the 1.59 eV calculated previously for the nitrosyl-to-isonitrosyl linkage isomerism in the five-coordinate (porphine)Fe(NO) analogue.

Infrared studies of carbon monoxide binding to carbon monoxide dehydrogenase/acetyl-CoA synthase from Moorella thermoacetica.

Carbon monoxide dehydrogenase/acetyl-CoA synthase (CODH/ACS) is a bifunctional enzyme that catalyzes the reversible reduction of carbon dioxide into carbon monoxide and the coupled synthesis of acetyl-CoA from the carbon monoxide produced. Exposure of CODH/ACS from Moorella thermoacetica to carbon monoxide gives rise to several infrared bands in the 2100-1900 cm(-1) spectral region that are attributed to the formation of metal-coordinated carbon monoxide species. Infrared bands attributable to M-CO are not detected in the as-isolated enzyme, suggesting that the enzyme does not contain intrinsic metal-coordinated CO ligands. A band detected at 1996 cm(-1) in the CO-flushed enzyme is assigned as arising from CO binding to a metal center in cluster A of the ACS subunit. The frequency of this band is most consistent with it arising from a terminally coordinated Ni(I) carbonyl. Multiple infrared bands at 2078, 2044, 1970, 1959, and 1901 cm(-1) are attributed to CO binding at cluster C of the CODH subunit. All infrared bands attributed to metal carbonyls decay in a time-dependent fashion as CO(2) appears in the solution. These observations are consistent with the enzyme-catalyzed oxidation of carbon monoxide until it is completely depleted from solution during the course of the experiments.

Light-induced metastable linkage isomers of ruthenium sulfur dioxide complexes.

The irradiation of ruthenium-sulfur dioxide complexes of general formula trans-[Ru(II)(NH(3))(4)(SO(2))X]Y with laser light at low temperature results in linkage isomerization of SO(2), starting with eta(1)-planar S-bound to eta(2)-side S,O-bound SO(2). The solid-state photoreaction proceeds with retention of sample crystallinity. Following work on trans-[Ru(NH(3))(4)Cl(eta(1)-SO(2))]Cl and trans-[Ru(NH(3))(4)(H(2)O)(eta(1)-SO2)](C(6)H(5)SO(3))(2) (Kovalevsky, A. Y.; Bagley, K. A.; Coppens, P. J. Am. Chem. Soc. 2002, 124, 9241-9248), we describe photocrystallographic, IR, DSC, and theoretical studies of trans-[Ru(II)(NH(3))(4)(SO(2))X]Y complexes with (X = Cl(-), H(2)O, or CF(3)COO(-) (TFA(-))) and a number of different counterions (Y = Cl(-), C(6)H(5)SO(3)(-), Tos(-), or TFA(-)). Low temperature IR experiments indicate the frequency of the asymmetric and symmetric stretching vibrations of the Ru-coordinated SO(2) to be downshifted by about 100 and 165 cm(-1), respectively. Variation of the trans-to-SO(2) ligand and the counterion increases the MS2 decay temperature from 230 K (trans-[Ru(II)(NH(3))(4)(SO(2))Cl]Cl) to 276 K (trans-[Ru(II)(NH(3))(4)(SO(2))(H(2)O)](Tos)(2)). The stability of the MS2 state correlates with increasing sigma-donating ability of the trans ligand and the size of the counterion. Quantum chemical DFT calculations indicate the existence of a third eta(1)-O-bound (MS1) isomer, the two metastable states being 0.1-0.6 eV above the energy of the ground-state complex.

The first photocrystallographic evidence for light-induced metastable linkage isomers of ruthenium sulfur dioxide complexes.

Light-induced metastable linkage isomers of trans-[Ru(NH(3))(4)Cl(SO(2))]Cl and trans-[Ru(NH(3))(4)(H(2)O)(SO(2))](C(6)H(5)SO(3))(2) have been identified for the first time using photocrystallographic methods. In both linkage isomers the SO(2) ligand is side bound, but the Ru-O and Ru-S distances are considerably longer and almost equal in the trans-H(2)O isomer. DFT calculations confirm that both isomers correspond to minima on the ground-state potential energy surface and also predict the existence of a second oxygen-bound isomer for both compounds. The decay of the light-induced species has been studied by both DSC and IR. Activation energies for the thermal back-reaction, as derived from the temperature-dependent disappearance of light-induced IR bands, are 50.0 and 58.4 kJ/mol for the two isomers, which is larger than the corresponding numbers for photoinduced side-bound nitrosyl linkage isomers.

Infrared studies of the CO-inhibited form of the Fe-only hydrogenase from Clostridium pasteurianum I: examination of its light sensitivity at cryogenic temperatures.

Infrared spectroscopy has been used to examine the oxidized and CO-inhibited forms of Fe-only hydrogenase I from Clostridium pasteurianum. For the oxidized enzyme, five bands are detected in the infrared spectral region between 2100 and 1800 cm(-1). The pattern of infrared bands is consistent with the presence of two terminally coordinated carbon monoxide molecules, two terminally coordinated cyanide molecules, and one bridging carbon monoxide molecule, ligated to the Fe atoms of the active site [2Fe] subcluster. Infrared spectra of the carbon monoxide-inhibited state, prepared using both natural abundance CO and 13CO, indicate that the two terminally coordinated CO ligands that are intrinsic to the enzyme are coordinated to different Fe atoms of the active site [2Fe] subcluster. Irradiation of the CO-inhibited state at cryogenic temperatures gives rise to two species with dramatically different infrared spectra. The first species has an infrared spectrum identical to the spectrum of the oxidized enzyme, and can be assigned as arising from the photolysis of the exogenous CO from the active site. This species, which has been observed in X-ray crystallographic measurements [Lemon, B. J., and Peters, J. W. (2000) J. Am. Chem. Soc. 122, 3793], decays above 150 K. The second light-induced species decays above 80 K and is characterized by loss of the infrared band associated with the Fe bridging CO at 1809 cm(-1). Potential models for the second photolysis event are discussed.