Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Parallel-Sampling ADC Architecture for Multi-carrier Signals

This chapter starts with a brief introduction of broadband multi-carrier transmission in Sect. 3.1. Section 3.2 describes the amplitude properties of multi-carrier signals, especially their large peak-to-average ratio. A discussion of the ADC dynamic range requirement for a multi-carrier system is given in Sect. 3.3. Section 3.4 reviews power reduction techniques to enhance the SNR of noise limited ADCs in advanced CMOS technologies. Section 3.5 presents a parallel-sampling architecture for ADCs to convert multi-carrier signals efficiently by exploiting their amplitude statistical properties. ADCs with this architecture are able to have a larger input signal range without causing excessive distortion while showing an improved accuracy over the small amplitudes that have much higher probability of occurrence due to the multi-carrier signal amplitude properties. The power consumption and area of ADCs with the parallel-sampling architecture can be reduced to achieve a desired SNR for multi-carrier signals compared to conventional ADCs. Section 3.6 proposes four implementation options of the parallel-sampling ADC architecture and Sect. 3.7 concludes the chapter