Iatrogenic Vascular Injuries in Resource-Limited Setting: A 4-Year Experience Monocentric Retrospective Study.

Background: Iatrogenic vascular injuries (IVIs) due to diagnostic and therapeutic interventions are known but rare or probably under-reported. We present our four-year findings on patients with IVIs after catheterization or surgery who underwent vascular surgical repairs in a resource-limited setting. Methods: A retrospective case series study between Jun 2018 and Sep 2022 of 35 patients diagnosed with IVIs and treated surgically at our hospital was included. The data on IVIs including patient characteristics, causes and type of injury, treatment, and outcomes were collected and analyzed. Results: The mean age was 37.12± 17.0 years, and most patients (65.7%) were male. Of the 35 IVIs, 21 were caused by percutaneous procedures, while 14 occurred intraoperatively and affected various arteries and veins. The main injured vessels were the femoral artery (20%) and direct blood vessel puncture made by non-qualified specialists (42.9%) during dialysis cannulation was the main cause. The intraoperative IVI affected the inferior vena cava in three patients, the aorta in two patients, the external iliac artery in four, the tibial and popliteal arteries in four, and the internal carotid artery in one. The following types of repairs were recorded: direct suture of the vessel with or without endarterectomy (71.4%), synthetic patch placement (25.7%), ligation (8.6%), bypass or interposition graft (14.3%), and thromboembolectomy (5.7%). Vascular repair was successful in 32 (91.4%) patients while three patients (8.6%) were expired. Complications occurred in 7 (20%) patients, of which superficial wound infections were the common complication (11.6%) and were treated with proper antibiotic therapy. Conclusion: Prompt identification of IVIs, as well as proper triage for future treatment, can enhance patient outcomes. Our data showed that non-qualified specialists seem to be responsible for the majority of IVIs. For that, we emphasize the importance of performing vascular procedures by a qualified specialist with adequate training.

Novel solvents for sustainable production of specialty chemicals.

We discuss novel solvents that improve the sustainability of various chemical reactions and processes. These alternative solvents include organic-aqueous tunable solvents; near-critical water; switchable piperylene sulfone, a volatile dimethylsulfoxide substitute; and reversible ionic liquids. These solvents are advantageous to a wide variety of reactions because they reduce waste and energy demand by coupling homogeneous reactions with heterogeneous separations, acting as in situ acid or base catalysts, and providing simple and efficient postreaction separations.

Combining the benefits of homogeneous and heterogeneous catalysis with tunable solvents and nearcritical water.

The greatest advantage of heterogeneous catalysis is the ease of separation, while the disadvantages are often limited activity and selectivity. We report solvents that use tunable phase behavior to achieve homogeneous catalysis with ease of separation. Tunable solvents are homogeneous mixtures of water or polyethylene glycol with organics such as acetonitrile, dioxane, and THF that can be used for homogeneously catalyzed reactions. Modest pressures of a soluble gas, generally CO2, achieve facile post-reaction heterogeneous separation of products from the catalyst. Examples shown here are rhodium-catalyzed hydroformylation of 1-octene and p-methylstyrene and palladium catalyzed C-O coupling to produce o-tolyl-3,5-xylyl ether and 3,5-di-tert-butylphenol. Both were successfully carried out in homogeneous tunable solvents followed by separation efficiencies of up to 99% with CO2 pressures of 3 MPa. Further examples in tunable solvents are enzyme catalyzed reactions such as kinetic resolution of rac-1-phenylethyl acetate and hydrolysis of 2-phenylethyl acetate (2PEA) to 2-phenylethanol (2PE). Another tunable solvent is nearcritical water (NCW), whose unique properties offer advantages for developing sustainable alternatives to traditional processes. Some examples discussed are Friedel-Crafts alkylation and acylation, hydrolysis of benzoate esters, and water-catalyzed deprotection of N-Boc-protected amine compounds.

Combining homogeneous catalysis with heterogeneous separation using tunable solvent systems.

Tunable solvent systems couple homogeneous catalytic reactions to heterogeneous separations, thereby combining multiple unit operations into a single step and subsequently reducing waste generation and improving process economics. In addition, tunable solvents can require less energy than traditional separations, such as distillation. We extend the impact of such solvents by reporting on the application of two previously described carbon dioxide tunable solvent systems: polyethylene glycol (PEG)/organic tunable solvents (POTS) and organic/aqueous tunable solvents (OATS). In particular, we studied: (1) the palladium catalyzed carbon-oxygen coupling of 1-bromo-3,5-dimethylbenzene and o-cresol to potassium hydroxide to produce o-tolyl-3,5-xylyl ether and 1-bromo-3,5-di-tert-butylbenzene to potassium hydroxide to produce 3,5-di-tert-butylphenol in PEG400/1,4-dioxane/water and (2) the rhodium-catalyzed hydroformylation of p-methylstyrene in water/acetonitrile to form 2-(p-tolyl) propanal. In addition, we introduce a novel tunable solvent system based on a modified OATS where propane replaces carbon dioxide. This represents the first use of propane in a tunable solvent system.