The recent definitions on intra-abdominal pressure (IAP), intra-abdominal volume (IAV) and abdominal compliance (C_ab) are a step forward in understanding these important concepts. They help our understanding of the pathophysiology, aetiology, prognosis, and treatment of patients with low C_ab. However, there is still a relatively poor understanding of the different methods used to measure IAP, IAV and C_ab and how certain conditions may affect the results. This review will give a concise overview of the different methods to assess and estimate C_ab; it will list important conditions that may affect baseline values and suggest some therapeutic options. Abdominal compliance (C_ab), defined as a measure of the ease of abdominal expansion, is measured differently than IAP. The compliance of the abdominal wall is only a part of the total abdominal pressure-volume (PV) relationship. Measurement or estimation of C_ab is difficult at the bedside and can only be done in a case of change (removal or addition) in IAV. The different measurement techniques will be discussed in relation to decreases (ascites drainage, haematoma evacuation, gastric suctioning) or increases in IAV (gastric insufflation, laparoscopy with CO₂ pneumoperitoneum, peritoneal dialysis). More specific techniques using the interactions between the thoracic and abdominal compartment during positive pressure ventilation will also be discussed (low flow PV loop, respiratory IAP variations, respiratory abdominal variation test, mean IAP and abdominal pressure variation), together with the concept of the polycompartment model. The relation between IAV and IAP is linear at low IAV and becomes curvilinear and exponential at higher volumes. Specific conditions in relation to increased (previous pregnancy or laparoscopy, gynoid fat distribution, ellipse-shaped internal abdominal perimeter) or decreased C_ab (obesity, fluid overload, android fat distribution, sphere-shaped internal abdominal perimeter) will be discussed as well as their impact on baseline IAV, IAP, reshaping capacity and abdominal workspace volume. Finally, we suggest possible treatment options in situations of unadapted IAV according to existing C_ab, which results in high IAP. A large overlap exists between the treatment of patients with abdominal hypertension and those with low C_ab. The C_ab plays a key role in understanding the deleterious effects of unadapted IAV on IAP and end-organ perfusion and function. If we can identify patients with low C_ab, we can anticipate and select the most appropriate surgical treatment to avoid complications such as IAH or ACS. The recent definitions on intra-abdominal pressure (IAP), intra-abdominal volume (IAV) and abdominal compliance (C_ab) are a step forward in understanding these important concepts. They help our understanding of the pathophysiology, aetiology, prognosis, and treatment of patients with low C_ab. However, there is still a relatively poor understanding of the different methods used to measure IAP, IAV and C_ab and how certain conditions may affect the results. This review will give a concise overview of the different methods to assess and estimate C_ab; it will list important conditions that may affect baseline values and suggest some therapeutic options. Abdominal compliance (C_ab), defined as a measure of the ease of abdominal expansion, is measured differently than IAP. The compliance of the abdominal wall is only a part of the total abdominal pressure-volume (PV) relationship. Measurement or estimation of C_ab is difficult at the bedside and can only be done in a case of change (removal or addition) in IAV. The different measurement techniques will be discussed in relation to decreases (ascites drainage, haematoma evacuation, gastric suctioning) or increases in IAV (gastric insufflation, laparoscopy with CO₂ pneumoperitoneum, peritoneal dialysis). More specific techniques using the interactions between the thoracic and abdominal compartment during positive pressure ventilation will also be discussed (low flow PV loop, respiratory IAP variations, respiratory abdominal variation test, mean IAP and abdominal pressure variation), together with the concept of the polycompartment model. The relation between IAV and IAP is linear at low IAV and becomes curvilinear and exponential at higher volumes. Specific conditions in relation to increased (previous pregnancy or laparoscopy, gynoid fat distribution, ellipse-shaped internal abdominal perimeter) or decreased C_ab (obesity, fluid overload, android fat distribution, sphere-shaped internal abdominal perimeter) will be discussed as well as their impact on baseline IAV, IAP, reshaping capacity and abdominal workspace volume. Finally, we suggest possible treatment options in situations of unadapted IAV according to existing C_ab, which results in high IAP. A large overlap exists between the treatment of patients with abdominal hypertension and those with low C_ab. The C_ab plays a key role in understanding the deleterious effects of unadapted IAV on IAP and end-organ perfusion and function. If we can identify patients with low C_ab, we can anticipate and select the most appropriate surgical treatment to avoid complications such as IAH or ACS.

Objective : The objective of the study was to gauge the effect of storage lesions on the dielectric response of red blood cells (RBC), in particular those processes linked to deformations of the cellular membrane known as the β -dispersion. Approach : The dielectric response of RBC suspensions, exposed to blood-bank cold storage, was studied using time-domain dielectric spectroscopy (TDDS) in the frequency range of 500 kHz up to 1 GHz. The measured dielectric processes are characterized by their dielectric strength (Δ ε ) and relaxation time (τ). Changes in the dielectric properties of the RBC suspensions due to storage-related lesions were evaluated. For a quantitative characterization of RBC lesions, we measured the deformability of fresh and stored RBC as expressed by their elongation ratio (ER), which was achieved under a shear stress of 3.0 Pa. Main Result : The results show that the storage of RBC induced a statistically significant decrease of dielectric relaxation times. In addition, a sound correlation between the mean values of ER and the relaxation times was observed (Spearman’s correlation coefficient ρ = 0.847). We draw the conclusion that those alterations in the relaxation time are induced by changes in the shape of the RBC that happen during cold-storage. Significance : The evolution of the β -dispersion of RBC opens new possibilities in the blood bank inventory management.

Monitoring intra-abdominal pressure (IAP) has become a standard in intensive care units. Correlation between the abdominal wall’s thickness (AWTh) and IAP has been reported previously. The abdominal wall can be modeled as a compound of parallel dielectric slabs; changes in their width have a direct effect on the reflection coefficient of the abdominal wall at microwave frequencies. This work describes the design of a reflectometry system and its proof-of-concept trial on five patients during laparoscopic surgery. The system complies with IEEE Std. C95.1-2005 concerning exposure of humans to microwave electromagnetic fields in controlled environments. The results putatively show an inverse correlation between IAP and the reflection coefficient, and a strong dependence on the body mass index. A better understanding of the dynamics in the changes of the AWTh (during intra-abdominal hypertension) will allow further development of a microwave-based technique for the continuous non-invasive indirect monitoring of IAP in critical patients.

Ancient rock engravings evoke the interest of archeologists and art historians as an important remnant of human cultures. Traditionally, engraved images are studied based on iconography, iconology, and stylistic characteristics, with little emphasis on execution technology. In contrast, the research method presented in this study strives to characterize the techniques adopted for making rock engravings in ancient times, with technological variations considered as indicators of the engraver’s production process. 3-D scans of two ancient engravings and contemporary graffiti were obtained from Site 25 in Timna Park, Southern Israel. The models were analyzed with ArchCUT3-D, a software specifically developed to precisely evaluate the 3-D micromorphological characteristics of the incisions making up the engraving. The software analyzes the surface micromorphology by extracting 3-D slices of the incisions using an accurate and repeatable method. Our results indicate that different incisions were executed by remarkably distinct techniques of stroking the rock surface with a sharp tool. The identification of discriminant characteristics enabled us to demonstrate the particularities of the engraving operations, such as ergonomic conditions and the level of consistency of the engraving gesture. ArchCUT3-D thus provides a computational method for incision technique recognition through micromorphology specifications, and the reconstruction of engraving gestures and individual production procedures.