Smoking and its effects on the healing process of chronic wounds

The rat as an animal model in chronic wound research: An update

The increasing global prevalence of chronic wounds underscores the growing importance of developing effective animal models for their study. This review offers a critical evaluation of the strengths and limitations of rat models frequently employed in chronic wound research and proposes potential improvements. It explores these models in the context of key comorbidities, including diabetes, venous and arterial insufficiency, pressure-induced blood flow obstruction, and infections. Additionally, the review examines important wound factors including age, sex, smoking, and the impact of anesthetic and analgesic drugs, acknowledging their substantial effects on research outcomes. A thorough understanding of these variables is crucial for refining animal models and can provide valuable insights for future research endeavors.

Predictors of surgical site infection following reconstructive flap surgery: A multi-institutional analysis of 37,177 patients

Purpose

Rates of surgical site infection (SSI) following reconstructive flap surgeries (RFS) vary according to flap recipient site, potentially leading to flap failure. This is the largest study to determine predictors of SSI following RFS across recipient sites.

Methods

The National Surgical Quality Improvement Program database was queried for patients undergoing any flap procedure from years 2005 to 2020. RFS involving grafts, skin flaps, or flaps with unknown recipient site were excluded. Patients were stratified according to recipient site: breast, trunk, head and neck (H&N), upper and lower extremities (UE&LE). The primary outcome was the incidence of SSI within 30 days following surgery. Descriptive statistics were calculated. Bivariate analysis and multivariate logistic regression were performed to determine predictors of SSI following RFS.

Results

37,177 patients underwent RFS, of whom 7.5% (n = 2,776) developed SSI. A significantly greater proportion of patients who underwent LE (n = 318, 10.7%) and trunk (n = 1,091, 10.4%) reconstruction developed SSI compared to those who underwent breast (n = 1,201, 6.3%), UE (n = 32, 4.4%), and H&N (n = 100, 4.2%) reconstruction (p < .001). Longer operating times were significant predictors of SSI following RFS across all sites. The strongest predictors of SSI were presence of open wound following trunk and H&N reconstruction [adjusted odds ratio (aOR) 95% confidence interval (CI) 1.82 (1.57-2.11) and 1.75 (1.57-1.95)], disseminated cancer following LE reconstruction [aOR (CI) 3.58 (2.324-5.53)], and history of cardiovascular accident or stroke following breast reconstruction [aOR (CI) 16.97 (2.72-105.82)].

Conclusion

Longer operating time was a significant predictor of SSI regardless of reconstruction site. Reducing operating times through proper surgical planning might help mitigate the risk of SSI following RFS. Our findings should be used to guide patient selection, counseling, and surgical planning prior to RFS.

What is the likely impact on surgical site infections in Australian hospitals if smoking rates are reduced? A cost analysis

INTRODUCTION

Assisting smokers to quit before surgery reduces surgical site infection (SSI) risk. The short-term economic benefits of reducing SSIs by embedding tobacco dependence treatment in Australian hospitals are unknown. Estimated annual number of SSIs prevented, and hospital bed-days (HBD) and costs saved from reducing smoking before surgery are calculated.

METHODS

The most recent number of surgical procedures and SSI rates for Australia were sourced. The number of smokers and non-smokers having a SSI were calculated using the UK Royal College of Physicians reported adjusted odds ratio (1.79), and the proportion of SSIs attributable to smoking calculated. The potential impact fraction was used to estimate reductions in SSIs and associated HBDs and costs from reducing the smoking rates among surgical patients from 23.9% to 10% or 5% targets. Uncertainty around the final estimates was calculated using probabilistic sensitivity analysis.

RESULTS

In 2016-17, approximately 40,593 (95% UI 32,543, 50,239) people having a surgical procedure in Australia experienced a SSI leading to 101,888 extra days (95% UI 49,988, 200,822) in hospital. If the smoking rate among surgical patients was reduced to 10%, 3,580 (95% UI 2,312, 5,178) SSIs would be prevented, and 8,985 (95% UI 4,094, 19,153) HBDs and $19.1M (95% UI $7.7M, $42.5M) saved in one year. If the smoking rate was reduced to 5%, 4,867 (95% UI 3,268, 6,867) SSIs would be prevented, and 12,217 (95% UI 5,614, 25,642) HBDs and $26.0M (95% UI $10.8M, $57.0M) would be saved.

CONCLUSIONS

The findings suggest achieving smoking rate targets of 10% or 5% would provide substantial short-term health and economic benefits through reductions in SSIs. Embedding tobacco dependence treatment in Australian hospitals would provide value for money by reducing costs and improving clinical quality and safety. A more comprehensive, modelled economic evaluation synthesising the best available evidence is needed to confirm findings.

An observational study protocol to explore loneliness and systemic inflammation in an older adult population with chronic venous leg ulcers

BACKGROUND

Chronic venous leg ulcers (CVLUs) are the most common type of lower extremity wound. Even when treated with evidenced-based care, 30-50% of CVLUs fail to heal. A specific gap exists about the association between psychosocial stressors, particularly loneliness, and biomarkers of inflammation and immunity. Loneliness is highly prevalent in persons with CVLUs, has damaging effects on health, and contributes to the development of multiple chronic conditions, promotes aberrant inflammation, and diminishes healing. However, the confluence of loneliness, inflammation and the wound healing trajectory has not been elucidated; specifically whether loneliness substantially mediates systemic inflammation and alters healing over time. This study seeks to address whether there is a specific biomarker profile associated with loneliness, CVLUs, and wound healing that is different from non-lonely persons with CVLUs.

METHODS

An observational prospective study will identify, characterize and explore associations among psychosocial stressors, symptoms and biomarkers between 2 CVLU groups, with loneliness+ (n = 28) and without loneliness- (n = 28) during 4 weeks of wound treatment, measured at 3 time points. We will examine psychosocial stressors and symptoms using psychometrically-sound measures include PROMIS® and other questionnaires for loneliness, social isolation, depression, anxiety, stigma, sleep, fatigue, pain, quality of life, cognition, and function. Demographics data including health history, sex, age, wound type and size, wound age, and treatment will be recorded from the electronic health record. We will characterize a biomarker panel of inflammatory genes including chemotaxic and growth factors, vascular damage, and immune regulators that express in response to loneliness to loneliness and CVLUs using well-established RNA sequence and PCR methods for whole blood samples. In an exploratory aim we will explore whether age and sex/psychological stressors and symptoms indicate potential moderation/mediation of the effect of loneliness on the biomarker profile over the study period.

DISCUSSION

This study will provide insight into the influence of psychosocial stressors, symptoms, and biological mechanisms on wound healing, towards advancing a future healing prediction model and interventions to address these stressors and symptoms experienced by persons with CVLUs.

The Impact of Tobacco Smoking Upon Chronic/Recurrent Tonsillitis and Post Tonsillectomy Bleeding

Introduction Smoking has many adverse effects on the oral and pharyngeal mucosa. Outcomes may be developing tonsillar infections and predisposing for post tonsillectomy bleeding (PTB).

Objective The objective of our study was to determine whether smokers have more chronic/recurrent tonsillitis indicating for tonsillectomy or develop more PTB episodes.

Methods We conducted a retrospective study on two groups of adults (age ≥18 years). Cohort 1: Smoking among patients who underwent tonsillectomy for recurrent/chronic tonsillitis. Cohort 2: Smoking among patients requiring control of PTB that were operated primarily for recurrent/chronic tonsillitis. Cohort 1 served as a population-reference for the second. We retrieved the data from medical records.

Results Cohort 1: 206 adults aged 18–50 years (mean 26 ± 7.6). 28% (57 patients) were smokers, versus 24% and 20% in the general population (in the years 2000 and 2010; p = 0.5, p = 0.18, respectively). Cohort 2: 114 adults aged 18–73 years (mean 26 ± 7.6). 43% were smokers, double the incidence in the general population (p = 0.004, p = 0.0004, in 2000 and 2010, respectively), and 1.5 times cohort 1 (p = 0.02). Smoking rates among bleeders on post-operative days 8–10 and later than day 10 were 53% and 60% (p = 0.0005 and p < 0.0001, respectively). Five of ten patients presenting a second PTB were smokers. Timing of re-bleedings was similar to their first PTB and dated similarly as first PTB of the entire group, mean 5.6 days (SD ± 3.2).

Conclusion Smokers may encounter more chronic/recurrent tonsillitis episodes, indicating tonsillectomy and significantly are more prone for PTB. Smoking cessation may perhaps diminish recurrent/chronic tonsillitis. Whether pre-operative abstinence or its length would reduce PTB incidence is yet to be determined.

Pharyngocutaneous Fistula after Total Laryngectomy: Risk Factors with Emphasis on Previous Radiotherapy and Heavy Smoking

Objective

In this retrospective cohort study, we aimed to determine the incidence of pharyngocutaneous fistula (PCF) after total laryngectomy (TL) and to define the possible predictors for PCF formation.

Methods

The medical records of 198 patients with laryngeal squamous cell carcinoma who underwent TL were reviewed. After the exclusion of patients with history of free flap reconstruction, previous laryngeal surgery, and previous radiotherapy (RT) for other primary cancers, the risk factors for PCF were analyzed in 183 patients who were included in the study.

Results

The overall incidence of PCF was 20.2%. A history of heavy smoking and previous RT were detected as independent risk factors in both univariate (p=0.004 and p=0.007, respectively) and multivariate (p=0.005) analyses. Preoperative tracheotomy (PT) longer than 14 days was a risk factor for PCF among patients with PT in the univariate analysis (p=0.031). Overall three- and five-year survival rates were statistically indifferent between the PCF and non-PCF groups (p>0.05). However, the overall five-year survival rate was lesser in the persistent PCF group (47%) than in the non-persistent PCF group (83%) (p=0.038).

Conclusion

Heavy smoking and previous RT are independent risk factors for PCF, and the persistence of PCF decreases survival rates. Preventable measures should be taken to decrease the incidence and persistence of this complication of TL in the management of patients with possible risk factors.