RESUMO
Purpose: The objective of this study is to evaluate the effect of the coronavirus disease 2019 (COVID-19) pandemic on elective and emergent colorectal surgical practice. Methods: The population of this retrospective observational study consisted of all consecutive patients who underwent emergent or elective colorectal surgery between March 2019 and March 2021. The patients were divided into 2 groups: the prepandemic group who were treated between March 2019 and March 10, 2020, and the pandemic group who were treated between March 11, 2020 and March 2021. The rate of emergent operations was the primary outcome. The groups were compared based on the frequency of operations, distribution of tumoral features in malignant cases, and 90th-day mortality rates. Results: There were 180 and 121 patients in the prepandemic and pandemic groups, respectively. There were significantly more patients of the American Society of Anesthesiologists physical status stage IV with comorbidity in the pandemic group than in the prepandemic group (P = 0.016 and P < 0.001, respectively). The rate of emergent operations was significantly higher in the pandemic group than in the prepandemic group (49.6% vs. 26.7%, P < 0.001). There were significantly more patients who received non-resectional surgery in the pandemic group than in the prepandemic group (P = 0.002). Additionally, there were significantly more patients without resection among patients with a defunctioning stoma (P = 0.001). The length of hospital stay (LoS) was significantly shorter in the pandemic group than in the prepandemic group (P = 0.039). On the other hand, the mortality rate was significantly higher in the pandemic group than in the prepandemic group (15.7% vs. 6.1%, P = 0.011). Conclusion: The study findings suggested that the COVID-19 pandemic adversely affected colorectal surgical practices, resulting in more frequent emergent operations, non-resectional procedures with stoma formation, and higher mortality rates.
RESUMO
A novel image steganography technique in order to hide the ciphered voice data has been suggested in this work. The doctor's voice comments belonging to a coronavirus disease 2019 (COVID-19) patient are hidden in a medical image in order to protect the patient information. The introduced steganography technique is based on chaos theory. Firstly, the voice comments of the doctor are converted to an image and secondly, they are ciphered utilizing the suggested encryption algorithm based on a chaotic system. Then, they are embedded into the cover medical image. A lung angiography dual-energy computed tomography (CT) scan of a COVID-19 patient is used as a cover object. Numerical and security analyses of steganography method have been performed in MATLAB environment. The similarity metrics are calculated for R, G, B components of cover image and stego image as visual quality analysis metrics to examine the performance of the introduced steganography procedure. For a 512 × 512 pixel cover image, SSIM values are obtained as 0.8337, 0.7926, and 0.9273 for R, G, B components, respectively. Moreover, security analyses which are differential attack, histogram, information entropy, correlation of neighboring pixels and the initial condition sensitivity are carried out. The information entropy is calculated as 7.9993 bits utilizing the suggested steganography scheme. The mean value of the ten UACI and NPCR values are obtained as 33.5688% and 99.8069%, respectively. The results of security analysis have revealed that the presented steganography procedure is able to resist statistical attacks and the chaotic system-based steganography scheme shows the characteristics of the sensitive dependence on the initial condition and the secret key. The proposed steganography method which is based on a chaotic system has superior performance in terms of being robust against differential attack and hiding encrypted voice comments of the doctor. Moreover, the introduced algorithm is also resistant against exhaustive, known plaintext, and chosen plaintext attacks.
