Interventions to Reduce Surgical Waste Burden: A Systematic Review.

Background: Operating suites are significant drivers of waste, pollution, and costs. Surgeons can help fight the climate crisis by implementing innovative strategies aimed at mitigating the environmental impact of surgical procedures and decreasing operational costs, and moving toward a more sustainable healthcare system. This study aims to review the literature describing interventions that reduce surgical waste. Methods: PubMed, Cochrane, and Embase were searched. Studies reporting interventions to reduce operative waste, including emissions, energy, trash, and other, were included. Case reports, opinion-based reports, reviews, and meta-analyses were excluded. Study quality was rated using MINORS and Jadad scales. Data were extracted from each study to calculate waste on a per case basis. Narrative review of studies was performed rather than meta-analysis. Results: The search yielded 675 unique hits, of which 13 (level of evidence: I-III) met inclusion criteria. Included studies were categorized by intervention type in relation to the operating and procedure room. Three studies evaluated provider education initiatives, three evaluated setup of instruments, two evaluated single-use items, four evaluated technique changes, and one evaluated surgical venue. Seven studies reported significant reductions in disposable surgical waste throughput, and seven reported significant reductions in cost. Conclusions: The results of this systemic review demonstrated the effectiveness of surgical waste reduction initiatives in reducing waste volume, cost, and carbon emissions. Within plastic surgery, minimal surgical packs resulted in reduced gross waste and cost while promoting patient satisfaction in hand surgery, supporting the continued development and implementation of such initiatives in a surgical context.

Effective Local Anesthetic Use in Nasal Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Studies.

Intraoperative nerve blocks have shown promise in managing pain after nasal surgery. The purpose of this systematic review and meta-analysis was to analyze existing level I and II evidence on intraoperative nerve blocks in nasal surgery to optimize postoperative recovery. Methods: The primary outcome of this systematic review and meta-analysis was postoperative pain scores; secondary outcomes included perioperative opioid requirements, patient satisfaction scores, and time to first analgesic requirement. PubMed, Embase, and MEDLINE databases were searched, and two independent reviewers conducted article screening. Methodological quality assessment of studies utilized the Jadad instrument, and interrater reliability was assessed using Cohen kappa. An inverse-variance, fixed-effects model was used for meta-analysis with Cohen d used to normalize effect size between studies. I2 and Q statistics were used to assess interstudy variability. Results: Four studies were included for meta-analysis, totaling 265 randomized patients. The nerve blocks assessed included infraorbital nerve, sphenopalatine ganglion, external nasal nerve, central facial nerve blocks, and total nerve blocks. All demonstrated significantly reduced postoperative pain compared with controls, with a large effect size (P < 0.001). Opioid requirements were lower in the nerve block groups (P < 0.001), and patient satisfaction scores were higher (P < 0.001). Supplemental meta-analyses showed a longer time to first analgesic requirement for patients who received a nerve block (P < 0.001). Conclusions: These findings support the efficacy of nerve blocks in providing postoperative pain relief and enhancing patient satisfaction with pain management. Perioperative nerve blocks, in combination with general anesthesia, should be considered for postoperative pain control.

Comparative Pharmacokinetics of Δ9-Tetrahydrocannabinol in Adolescent and Adult Male and Female Rats.

Introduction: Studies in rodent models have shown that adolescent exposure to Δ9-THC, the psychotropic constituent of cannabis, produces long-lasting alterations in brain function and behavior. However, our understanding of how age and sex might influence the distribution and metabolism of THC in laboratory rodents is still incomplete. In the present report, we provide a comparative analysis of the pharmacokinetic (PK) properties of THC in adolescent and adult rats of both sexes, and outline several dissimilarities across these groups. Materials and Methods: A single (acute) or 2-week daily (subchronic) administration of THC (0.5 or 5 mg/kg, acute; 5 mg/kg, subchronic; intraperitoneal) was given to adolescent (33-day-old, acute; 30-44-day-old, subchronic) and young adult (70-day-old, acute only) male and female rats. THC and its first-pass metabolites-11-hydroxy-Δ9-THC (11-OH-THC) and 11-nor-9-carboxy-Δ9-THC (11-COOH-THC)-were quantified in plasma and brain tissue using a selective isotope-dilution liquid chromatography/tandem mass spectrometry assay. Changes in body temperature were measured using abdominally implanted microchips. Biotransformation of THC to its metabolites using freshly prepared liver microsomes was assessed. Results: At the acute 5 mg/kg dose, maximal plasma concentrations of THC were twice as high in adult than in adolescent rats. Conversely, in adults, brain concentrations and brain-to-plasma ratios for THC were substantially lower (25-50%) than those measured in adolescents. Similarly, plasma and brain concentrations of THC metabolites were higher in adolescent male rats compared with adult males. Interestingly, plasma and brain concentrations of the psychoactive THC metabolite 11-OH-THC were twofold to sevenfold higher in female animals of both ages compared with males. Moreover, liver microsomes from adolescent males and adolescent and adult females converted THC to 11-OH-THC twice as fast as adult male microsomes. A dose-dependent hypothermic response to THC was observed in females with 0.5 and 5 mg/kg THC, whereas only the highest dose elicited a response in males. Finally, subchronic administration of THC during adolescence did not significantly affect the drug's PK profile. Conclusions: The results reveal the existence of multiple age and sex differences in the distribution and metabolism of THC in rats, which might influence the pharmacological response to the drug.

Gendered Differences in Teaching Performance Evaluations of Obstetrics and Gynecology Residents.

OBJECTIVE: Teaching performance evaluations are commonly used for career development and advancement. Due to possible gendered expectations, implicit or explicit bias may emerge in evaluations completed by learners. This study investigated how third-year medical students evaluated teaching performance of obstetrics and gynecology resident physicians based on resident gender. SETTING: This study was conducted at the Medical College of Wisconsin in Milwaukee, Wisconsin. DESIGN: This retrospective mixed methods study examined teaching performance evaluations of obstetrics and gynecology resident physicians from 2010 to 2018, completed by third-year medical students. A two-sample, two-sided t-test was used to compare numerical scores. Deductive content analysis of written comments focused on specific categories: positive or negative agentic or communal demeanors and characteristics, teaching skills, character and professionalism, leadership abilities, clinical skills and knowledge, and frequency of words and phrases used to describe residents. SETTING: This study was conducted at the Medical College of Wisconsin in Milwaukee, Wisconsin. RESULTS: Of 83 residents (71 females, 12 males), there was no statistical significance in the teaching performance evaluation scores between male and female residents (n = 10,753 total completed evaluations). Female residents had lower scores than male residents; males tended not to score below 4 (5-point response scale; 5 = outstanding). Of 3,813 written comments, male residents had more positive comments, with statistical significance in communal characteristics (71.4% male, 53.9% female, p = 0.01). Female residents received more negative comments, with statistical significance in communal characteristics (7.5% female, 2.8% male, p = 0.01). Frequency of words presented that male residents had more "standout" traits ("outstanding," "excellent," "exemplary"), "ability" terms ("intelligent," "bright," "talented," "smart"), and were often considered "fun," "funny," and "humorous." Female residents were described by "compassion" terms ("kind," "compassionate"). CONCLUSION: Student-completed teaching performance evaluations are a valuable assessment of teaching skills and influence department recognition, award distribution, fellowship and employment opportunities. This study found that medical students did evaluate female residents differently than male residents. Understanding gendered expectations may assist in findings ways to address discrepancies between male and female physician evaluations.

3-D Perfusion Imaging Using Principal Curvature Detection Rendering.

Three-dimensional contrast-enhanced ultrasound (CEUS) imaging presents a clear advantage over its 2-D counterpart in detecting and characterizing suspicious lesions as it properly surveys the inherent heterogeneity of tumors. However, 3-D CEUS is also slow compared to 2-D CEUS and tends to undersample the microbubble wash-in. This makes it difficult to resolve the feeding vessels, an important oncogenic marker, from the background perfusion cloud. Contrast-enhanced Doppler is helpful in isolating this conduit flow, but requires too many pulses in conventional line-by-line beamforming design. Recent breakthroughs in plane-wave imaging have greatly accelerated the volumetric imaging frame rate, but volumetric Doppler angiography still remains challenging when considering real-time limitations on the Doppler ensemble length. In this work, we demonstrate the feasibility of volumetric CEUS angiography subjected to real-time imaging constraints. Namely, we show how principal curvature detection can significantly improve 3-D rendering of relatively noisy ultrasound angiograms without degrading the spatial resolution while subjected to a reasonable Doppler ensemble size. Singular value decomposition is also shown to be capable of identifying the quasi-stationary capillary perfusion.

The Role of Microbubble Echo Phase Lag in Multipulse Contrast-Enhanced Ultrasound Imaging.

In this paper, we assess the importance of microbubble shell composition for contrast-enhanced imaging sequences commonly used on clinical scanners. While the gas core dynamics are primarily responsible for the nonlinear harmonic response of microbubbles at diagnostic pressures, it is now understood that the shell rheology plays a dominant role in the nonlinear response of microbubbles subjected to low acoustic pressures. Of particular interest here, acoustic pressures of tens of kilopascal can cause a reversible phase transition of the phospholipid coatings from a stiff elastic organized state to a less stiff disorganized buckled state. Such a transition from elastic to buckled shell induces a steep variation of the shell elasticity, which alters the microbubble acoustic scattering properties. We demonstrate in this paper that this mechanism plays a dominant role in contrast pulse sequences that modulate the amplitude of the insonifying pulse pressure. The contrast-to-tissue ratio (CTR) for amplitude modulation (AM), pulse inversion (PI), and amplitude modulation pulse inversion (AMPI) is measured in vitro for Definity, Sonazoid, both lipid-encapsulted microbubbles, and the albumin-coated Optison. It is found that pulse sequences using AM significantly enhanced the nonlinear response of all studied microbubbles compared to PI (up to 15 dB more) when low insonation pressures under 200 kPa were used. Further investigation reveals that the origin of the hyperechoicity is a small phase lag occurring between the echoes from the full-and half-amplitude driving pulses, and that the effect could be attributed to the shell softening dynamics of lipid and albumin coatings. We assess that this additional phase in microbubble ultrasound scattering can have a dominant role in the CTR achieved in contrast sequences using AM. We also show that the pressure dependent phase lag is a specific marker for microbubbles with no equivalent in tissue, which can be used to segment microbubbles from the tissue harmonics and significantly increase the CTR.

Functional Reconstruction of Tracheal Defects by Protein-Loaded, Cell-Seeded, Fibrous Constructs in Rabbits.

Tracheal stenosis is a life-threatening disease and current treatments include surgical reconstruction with autologous rib cartilage and the highly complex slide tracheoplasty surgical technique. We propose using a sustainable implant, composed of a tunable, fibrous scaffold with encapsulated chondrogenic growth factor (transforming growth factor-beta3 [TGF-ß3]) or seeded allogeneic rabbit bone marrow mesenchymal stromal cells (BMSCs). In vivo functionality of these constructs was determined by implanting them in induced tracheal defects in rabbits for 6 or 12 weeks. The scaffolds maintained functional airways in a majority of the cases, with the BMSC-seeded group having an improved survival rate and the Scaffold-only group having a higher occurrence of more patent airways as determined by microcomputed tomography. The BMSC group had a greater accumulation of inflammatory cells over the graft, while also exhibiting normal epithelium, subepithelium, and cartilage formation. Overall, it was concluded that a simple, acellular scaffold is a viable option for tracheal tissue engineering, with the intraoperative addition of cells being an optional variation to the scaffolds.