Rock Quality Analysis using Empirical Techniques (RMR & Q-SYSTEM) along the Headrace of a Hydropower Project in Kalam, Swat, Pakistan

The principal goals of this research were to examine the rock mass classification (RMC) and characterization as well as the support assessment for the proposed headrace tunnel route of an approximately 11 km long hydropower project (HPP) in Kalam valley, Khyber Pakhtunkhwa (KP), Pakistan. It was important to look at the key discontinuity factors for the classification of rock masses. To accomplish the aim, field discontinuity surveys were carried out to obtain rock mass parameters, and collected samples along the proposed tunnel route. Furthermore, characterization and classification of rock mass have been done using empirical techniques (ET) such as Beiniawski's Rock Mass Rating (RMR) and Barton's Tunnelling Quality Index (Q). The rock types were identified as Kalam Quartz Diorite, Gabbro and Granodiorite from literature. The prominent discontinuity sets were evaluated by exporting discontinuity data to DIPS. Quality Index was determined by calculating, its parameters, Quality Index values range between 3.74-17.00, 3.74 (poor at DS-04), 7.08-7.33 (fair at DS-01, DS-11 and DS-18) and 10.07-17.00 (good at DS-02, DS-09, DS-13, DS-14, DS-17 and DS-19), whereas, rock mass classification values ranges from 47-60 (fair at DS-01, DS-02, DS-04, DS-09, DS-11, DS-13, DS-14, DS-18, DS-19) to 64 (good at DS-17). The rock support according to the RMR scheme suggests fully grouted systematic bolting 3 to 4 m in length and 1.5 to 2.5 m spaced and 50-100 mm shotcrete in the crown and 50 mm in sides, while Q-system suggests spot bolting to Systematic bolting with 40-100 mm unreinforced shotcrete

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

Background Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications. Methods We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC). Findings In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683–0·717]). Interpretation In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required. Funding British Journal of Surgery Society