Prolonged Bacteroides pyogenes infection in a patient with multiple lung abscesses.

Bacteroides pyogenes is naturally found in the oral microbiome of cats and dogs and hence exposure, especially bites from these animals, is a major risk factor for human infections. B pyogenes is known to cause infections that persist despite antibiotic treatment and can have serious clinical outcomes. We present a novel case of complex lung abscesses associated with B pyogenes infection. A 55 year old man presents with a 3-month history of productive cough, night sweats, and 5 kg weight loss. An initial chest radiograph revealed mass-like opacities in the right upper lobe (RUL), right middle lobe (RML), and left lower lobe (LLL). Over the next 4 years the patient underwent multiple investigations and antimicrobial treatments until resolution of the abscesses. We believe that metronidazole in combination with moxifloxacin was a key component in the clinical cure of this patient.

Total Knee Arthroplasty Revision in the Setting of Periprosthetic Joint Infection Resulting in Bone Cement Implantation Syndrome (BCIS), Pulseless Electrical Activity (PEA) Arrest, and Intraoperative Death: A Case Report and Literature Review.

An 87-year-old female with a history of total knee arthroplasty (TKA) presented to the emergency department (ED) for left knee pain in the setting of recent methicillin-sensitive Staphylococcus aureus (MSSA) sepsis of unknown origin. She was subsequently diagnosed with a complicated symptomatic periprosthetic joint infection of her left TKA hardware and was admitted for TKA revision following an orthopedic surgery consultation. Upon arrival at the operating room (OR), standard American Society of Anesthesiology (ASA) monitors were applied. These included non-invasive blood pressure, electrocardiogram (ECG), pulse oximeter, and an esophageal temperature probe. The patient then underwent induction of general endotracheal anesthesia (GETA) without significant hemodynamic compromise. Intraoperatively, the patient tolerated the removal of her infected hardware without major complication but upon placement of the methyl methacrylate (MMA), commonly referred to as bone cement, the patient had an acute drop in her end-tidal carbon dioxide (EtCO2) and then developed significant bradycardia and hypotension. Despite rapid detection and treatment, the patient continued to collapse hemodynamically and was noted to be pulseless and in pulseless electrical activity (PEA) arrest on ECG. Cardiopulmonary resuscitation (CPR) was immediately started per the Advanced Cardiac Life Support (ACLS) algorithm. Roughly after 45 minutes of continuous CPR and multiple doses of 1 mg epinephrine, it was determined that the patient had suffered a catastrophic and fatal intraoperative event. A team decision was made to stop providing any lifesaving interventions. This patient's presentation is consistent with bone cement implantation syndrome (BCIS), an uncommon phenomenon that remains poorly understood. Two leading models for BCIS described in the literature are the monomer-mediated and embolus-mediated models. However, further research into BCIS is warranted to better understand its pathophysiology, incidence, as well as potential prophylactic measures, including the use of cementless arthroplasty. This complicated and fatal case serves as a reminder of the morbidity and mortality associated with BCIS and underscores that anesthesiology teams must remain vigilant and prepared during orthopedic joint procedures.

Bronchoalveolar Lavage and Oleic Acid Two-hit Model for Inducing Acute Respiratory Distress Syndrome in Swine Models.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) is a widespread and often fatal clinical syndrome marked by the acute onset of pulmonary edema and inflammatory-mediated disruptions in alveolar-capillary permeability resulting in impaired gas exchange and tissue oxygenation with subsequent acute respiratory failure that accounts for 10.4% of all intensive care unit admissions worldwide and boasts a mortality rate of 38.5%. The current treatment for ARDS remains largely supportive. This is largely because of the many challenges of achieving a stable and sustainable animal model that recreates the pathophysiology of ARDS experimentally in a controlled setting to allow research to elucidate potential treatments of ARDS moving forward. MATERIALS AND METHODS: The bronchoalveolar lavage and oleic acid models are currently the 2 most frequently used experimental models in inducing ARDS in animal models. This study demonstrated that combining them into a "two-hit model" can produce sustained ARDS in swine models per the Horowitz index (PaO2/FiO2 ratio of ≤300 mmHg). Additionally, expected changes in pH, pCO2, lung compliance, cytokines, and tissue histopathology were observed and add to our confidence and reliability that the "two-hit model" produces symptomatic ARDS in a manner very similar to that observed in humans. RESULTS AND CONCLUSIONS: In conclusion, we demonstrated a viable animal model of human ARDS that is maintained for a prolonged period, suitable for continuous monitoring of the progression, and evaluation of potential future treatments and procedures to reduce patient morbidity and mortality. To carry out this two-hit model, lung injury was induced through a combination of bronchoalveolar lavage and oleic acid administration and the disease process of ARDS is subsequently tracked through clinically relevant parameters such as respiratory mechanics, cytokine response, aretrial blood gas (ABG) changes, and observation of postmortem histopathologic changes. This promising new model has the capacity to successfully replicate human ARDS which is a well-known and notoriously multifactorial pathogenic process to reproduce experimentally for an extended period of time. The "two-hit model" is a viable and appropriate model for the research of novel treatments for ARDS.

Using individualized three-dimensional printed airway models to guide airway stent implantation.

Airway stents are used to manage central airway obstructions by restoring airway patency. Current manufactured stents are limited in shape and size, which pose issues in stent fenestrations needed to be manually created to allow collateral ventilation to airway branches. The precise location to place these fenestrations can be difficult to predict based on 2-dimensional computed tomography images. Inspiratory computed tomography scans were obtained from 3 patients and analysed using 3D-Slicer™, Blender™ and AutoDesk® Meshmixer™ programmes to obtain working 3D-airway models, which were 3D printed. Stent customizations were made based on 3D-model dimensions, and fenestrations into the stent were cut. The modified stents were then inserted as per usual technique. Two patients reported improved airway performance; however, stents were later removed due to symptoms related to in-stent sputum retention. In a third patient, the stent was removed a few weeks later due to the persistence of fistula leakage. The use of a 3D-printed personalized airway model allowed for more precise stent customization, optimizing stent fit and allowing for cross-ventilation of branching airways. We determine that an airway model is a beneficial tool for stent optimization but does not prevent the development of some stent-related complications such as airway secretions.