Epidemiology and Outcomes of Deep Surgical Site Infections Following Lung Transplantation

We conducted a retrospective study of deep surgical site infections (SSIs) among consecutive patients who underwent lung transplantation (LTx) at a single center from 2006 through 2010. Thirty‐one patients (5%) developed SSIs at median 25 days after LTx. Empyema was most common (42%), followed by surgical wound infections (29%), mediastinitis (16%), sternal osteomyelitis (6%), and pericarditis (6%). Pathogens included Gram‐positive bacteria (41%), Gram‐negative bacteria (41%), fungi (10%) and Mycobacterium abscessus, Mycoplasma hominis and Lactobacillus sp. (one each). Twenty‐three percent of SSIs were due to pathogens colonizing recipients' native lungs at time of LTx, suggesting surgical seeding as a source. Patient‐related independent risk factors for SSIs were diabetes and prior cardiothoracic surgery; procedure‐related independent risk factors were LTx from a female donor, prolonged ischemic time and number of perioperative red blood cell transfusions. Mediastinitis and sternal infections were not observed among patients undergoing minimally invasive LTx. SSIs were associated with 35% mortality at 1 year post‐LTx. Lengths of stay and mortality in‐hospital and at 6 months and 1 year were significantly greater for patients with SSIs other than empyema. In conclusion, deep SSIs were uncommon, but important complications in LTx recipients because of their diverse microbiology and association with increased mortality.     

Organizing: new ways to harness complexity

As systems evolve, their natural tendency is to become increasingly more complex. Studies in the field of complex systems have generated new perspectives on managing in social organizations such as hospitals. Much of this research appears as a natural extension of the cross-disciplinary field of systems theory. This is the second in a 5-part series on applying complex systems science to the traditional management concepts of planning, organizing, directing, coordinating, and controlling. In this article, the concept of organizing is explored from a complex systems perspective.     

An evaluation of hernia education in surgical residency programs

Purpose

The purpose of this study was to evaluate surgical residents’ educational experience related to ventral hernias.

Methods

A 16-question survey was sent to all program coordinators to distribute to their residents. Consent was obtained following a short introduction of the purpose of the survey. Comparisons based on training level were made using χ² test of independence, Fisher’s exact, and Fisher’s exact with Monte Carlo estimate as appropriate. A p value <0.05 was considered significant.

Results

The survey was returned by 183 residents from 250 surgical programs. Resident postgraduate year (PG-Y) level was equivalent among groups. Preferred techniques for open ventral hernia varied; the most common (32 %) was intra-abdominal placement of mesh with defect closure. Twenty-two percent of residents had not heard of the retrorectus technique for hernia repair, 48 % had not performed the operation, and 60 % were somewhat comfortable with and knew the general categories of mesh prosthetics products. Mesh choices, biologic and synthetic, varied among the different products. The most common type of hernia education was teaching in the operating room in 87 %, didactic lecture 69 %, and discussion at journal club 45 %. Number of procedures, comfort level with open and laparoscopic techniques, indications for mesh use and technique, familiarity and use of retrorectus repair, and type of hernia education varied significantly based on resident level (p < 0.05).

Conclusion

Exposure to hernia techniques and mesh prosthetics in surgical residency programs appears to vary. Further evaluation is needed and may help in standardizing curriculums for hernia repair for surgical residents.     

Precursor forms of substance P (SP) in nervous tissue: detection with antisera to SP, SP-Gly, and SP-Gly-Lys.

Antisera generated to substance P-Gly (SP-G) and substance P-Gly-Lys (SP-G-K), the likely unamidated COOH-terminally extended forms of substance P, were used to quantify and localize substance P precursor forms in hamster brain stem and spinal cord. The precursor determinant SP-G-K was liberated from larger heterogeneous forms by mild trypsinization of tissue extracts and was converted into the second precursor determinant, SP-G, by subsequent treatment with carboxypeptidase B. The basal levels of SP-G-K in brain stem and spinal cord were approximately equal to 0.5 pg/mg of tissue and rose 43- to 64-fold after trypsinization. Basal levels of SP-G were comparable to those of SP-G-K and rose 10- to 29-fold after combined enzyme treatments. Immunohistochemical labeling of axons and somata with anti-SP-G-K increased dramatically after trypsinization. This labeling was eliminated by preadsorption with authentic SP-G-K but not substance P or SP-G. Gel-permeation chromatography revealed SP-G-K-like immunoreactivity in fractions corresponding to considerably higher molecular weight than mature substance P. Collectively, these results support the hypothesis that substance P is synthesized from larger precursors and demonstrate that extended precursor forms are normally present in the axons and somata of neural systems that synthesize substance P.