The impact of intraoperative blood pressure variability on the risk of postoperative adverse outcomes in non-cardiac surgery: a systematic review

Hemodynamic stability during surgery seems to account for positive postoperative outcomes in patients. However, little is known about the impact of intraoperative blood pressure variability (IBPV) on the postoperative complications. The aim was to investigate whether IBPV is associated with the development of postoperative complications and what is the nature of this association. We conducted a systematic search in PubMed, Medical Subject Headings, Embase, Web of Science, SCOPUS, clinicaltrials.gov, and Cochrane Library on the 8th of April, 2021. We included studies that only focused on adults who underwent primarily elective, non-cardiac surgery in which intraoperative blood pressure variation was measured and analyzed in regard to postoperative, non-surgical complications. We identified 11 papers. The studies varied in terms of applied definitions of blood pressure variation, of which standard deviation and average real variability were the most commonly applied definitions. Among the studies, the most consistent analyzed outcome was a 30-day mortality. The studies presented highly heterogeneous results, even after taking into account only the studies of best quality. Both higher and lower IBPV were reported to be associated for postoperative complications. Based on a limited number of studies, IBPV does not seem to be a reliable indicator in predicting postoperative complications. Existing premises suggest that either higher or lower IBPV could contribute to postoperative complications. Taking into account the heterogeneity and quality of the studies, the conclusions may not be definitive.

Kinerja Filter Portabel Tepat Guna dalam Mereduksi Kekeruhan Air Banjir untuk Sanitasi atau MCK

During flood people had difficulties in obtaining clean water for sanitation (toilet). There was plenty of flood water but highly turbid. The water filter required electricity but its power outaged during flood. Filters usually used energy from electricity or gravity. This study evaluated the performance of a new handy-manually operated flood water portable filter. The standard of Permenkes No. 32/2017 was used as a reference. The flood water filter was pressurized by 0.025 kgf/cm2 and 0.051 kgf/cm2 and used local media: gravel, silica sand, anthracite, sponge. The results showed that pressure 0.025 kgf/cm2 was able to reduce turbidity from 220 NTU to 20.17 NTU with efficiency 90.83%. At 0.051 kgf/cm2 the filter was able to reduce turbidity from 220 NTU to 29.67 NTU with efficiency 86.52%. The pressure variation significantly affects the filtrate quality. The filter with pressure 0.025 kgf/cm2 could be applied for optimal filtration and produced 100-150 liters before clogging. This filter still needs to be studied related to physical strength, type and composition of media, portability and volume of water produced. This flood water filter will be an alternative solution for areas that often flood but no electricity or the power outage during flood.

Wellbore Integrity: An Integrated Experimental and Numerical Study to Investigate Pore Pressure Variation during Cement Hardening under Downhole Conditions

Summary Understanding the cement hardening process and determining the development of the state of stress in the cement under specific downhole conditions are challenging but fundamental requirements to perform an accurate prediction of wellbore integrity. As an essential component of the state of stress, the temporal variation of cement pore pressure is a critical factor that affects the occurrence of cement failure. In this study, we present a novel laboratory setup to measure the cement pore pressure variation during hardening under representative downhole conditions, including the pressure, temperature, and water exchange between the cement and formation. The pore pressure measurements are further incorporated with a staged finite element analysis (FEA) approach to investigate the state of stress development during cement hardening and to evaluate cement failure under different operations and after different wait-on-cement (WOC) periods. The laboratory measurements show that the external water supply from the formation significantly impedes the pore pressure drop in the cement. The numerical results indicate that the accelerated pore pressure decrease obtained without considering downhole conditions elevates the contact pressure at the cement-formation interfaces significantly and moderately increases the von Mises stress in the cement. The numerical results further predict that the accelerated pore pressure decrease leads to an overestimation of shear failure during pressure testing and steamflooding operations but an underestimation of debonding failure during severe fluid loss and injection-related cooling processes. Based on the results of the integrated laboratory and numerical approach, qualitative and quantitative suggestions are provided for field operations to inhibit wellbore integrity risk during the wellbore life cycle.

Influence of fluid pressure changes on the reactivation potential of pre-existing fractures: a case study in the Archaean metavolcanics of the Chitradurga region, India

The metavolcanics of Chitradurga region host numerous shallow crustal veins and fractures and faults of multiple orientations. Several high and low Pf cycles have been recorded in the region, leading to the reactivation of most of the pre-existing fractures for high Pf and selective reactivation of some well-oriented fractures under low Pf conditions. The pre-existing anisotropy (magnetic fabric) in the metavolcanics acted as the most prominent planar fabric for fracture propagation and vein emplacement under both conditions, thereby attaining maximum vein thickness. In this study, we emphasize the reactivation propensity of these pre-existing fracture planes under conditions of fluid pressure variation, related to the high and low Pf cycles. Multiple cycles of fluid-induced fracture reactivation make it difficult to quantify the maximum/minimum fluid pressure magnitudes. However, in this study we use the most appropriate fluid pressure magnitudes mathematically feasible for a shallow crustal depth of ∼2.4 km. We determine the changes in the reactivation potential with states of stress for the respective fracture orientations under both high and low Pf conditions. Dependence of fluid pressure variation on the opening angle of the fractures is also monitored. Finally, we comment on the failure mode and deformation behaviour of the fractures within the prevailing stress field inducing volumetric changes at the time of deformation. We find that deformation behaviour is directly related to the dip of the fracture planes.

Fully-Printable Soft Actuator with Variable Stiffness by Phase Transition and Hydraulic Regulations

Actuators with variable stiffness have vast potential in the field of compliant robotics. Morphological shape changes in the actuators are possible, while they retain their structural strength. They can shift between a rigid load-carrying state and a soft flexible state in a short transition period. This work presents a hydraulically actuated soft actuator fabricated by a fully 3D printing of shape memory polymer (SMP). The actuator shows a stiffness of 519 mN/mm at 20 ∘C and 45 mN/mm at 50 ∘C at the same pressure (0.2 MPa). This actuator demonstrates a high stiffness variation of 474 mN/mm (10 times the baseline stiffness) for a temperature change of 30 ∘C and a large variation (≈1150%) in average stiffness. A combined variation of both temperature (20–50 ∘C) and pressure (0–0.2 MPa) displays a stiffness variation of 501 mN/mm. The pressure variation (0–0.2 MPa) in the actuator also shows a large variation in the output force (1.46 N) at 50 ∘C compared to the output force variation (0.16 N) at 20 ∘C. The pressure variation is further utilized for bending the actuator. Varying the pressure (0–0.2 MPa) at 20 ∘C displayed no bending in the actuator. In contrast, the same variation of pressure at 50 ∘C displayed a bending angle of 80∘. A combined variation of both temperature (20–50 ∘C) and pressure (0–0.2 MPa) shows the ability to bend 80∘. At the same time, an additional weight (300 g) suspended to the actuator could increase its bending capability to 160∘. We demonstrated a soft robotic gripper varying its stiffness to carry objects (≈100 g) using two individual actuators.