Monitoring intra-abdominal pressure (IAP) in critical care patients is crucial for preventing intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS), with their severe consequences. The muscle contraction sensor (MC) introduced in this study offers a novel, non-invasive method with promising accuracy based on previous findings. This study further evaluates the MC accuracy and reproducibility and examines its correlation with objective IAP measurements obtained through a CO2 insufflator. We enrolled 41 patients undergoing elective laparoscopic gallbladder removal under general anesthesia with complete muscle relaxation. Two MC sensors were placed on the right and left sides of the abdomen, and elevated IAP was induced by insufflating CO2 into the peritoneal cavity. IAP measurements from the MC sensors were compared to the randomized IAP values set on the CO2 insufflator. Data from both methods were analyzed to assess the accuracy and agreement with the insufflator measurements. The MC sensor provided continuous and accurate detection of IAP changes. A Pearson correlation coefficient of 0.963 indicated a strong positive linear correlation between the MC sensor readings and the IAP values set on the insufflator. The coefficient of determination (R2) was 0.927, showing that the model explains 92.7% of the variation in IAP values based on the MC sensor signals. Receiver operating characteristic analysis demonstrated that the MC sensor system performed exceptionally well in identifying both IAH and ACS cases, with an area under the curve of 0.996 for IAH and 0.981 for ACS. The study introduces a transcutaneous pressure measuring device as an innovative, non-invasive method for assessing IAP. The system strongly correlates with IAP values measured by CO2 insufflation, indicating its accuracy. It thus could present an alternative to conventional IAP measurement in the future. The MC capability to deliver real-time, continuous data holds substantial potential for proactive patient care. By incorporating advanced analytics like machine learning, the system could detect trends and provide early warnings of dangerous IAP changes, enabling timely, targeted interventions to enhance outcomes for critically ill patients.

For a long time, trans-femoral venous pressure (FVP) measurement was considered a simple alternative for estimating intra-abdominal pressure (IAP). Since intravesical [IVP] and intragastric [IGP] pressure measurements are sometimes contraindicated for anatomical and pathophysiological reasons, FVP raised hopes, especially among pediatricians. Pediatric FVP validation studies have never been published; recent results from adult studies cast doubt on their interchangeability. Therefore, we compared for the first time the measurement agreement between FVP and IVP and IGP in children.

We prospectively compared FVP with IVP and IGP, according to the Abdominal Compartment Society validation criteria. Additionally, we analyzed the agreement as a function of IAP or right heart valve regurgitation and pulmonary hypertension.

In a real-life PICU study design, n = 39 children were included (median age 4.8 y, LOS-PICU 23 days, PRISM III score 11). In n = 660 FVP-IGP measurement pairs, the median IAP was 7 (range 1 to 23) mmHg; in n = 459 FVP-IVP measurement pairs, the median IAP was 6 (range 1to 16) mmHg. The measurement agreement was extremely low with both established methods (FVP-IGP: r2 0.13, mean bias -0.8 ± 4.4 mmHg, limits of agreement (LOA) -9.6/+8.0, percentage error (PE) 55%; FVP-IVP: r2 0.14, bias +0.5 ± 4.2 mmHg, limit of agreement (LOA) -7.9/+8.9, percentage error (PE) 51%). No effect of the a priori defined influencing factors on the measurement agreement could be demonstrated.

In a study cohort with a high proportion of critically ill children suffering from IAH, FVP did not agree reliably with either IVP or IGP. Its clinical use in critically ill children must therefore be strongly discouraged.

An elevated intra-abdominal pressure (IAP) above 12 mmHg is a pathological finding in critically ill patients. IAP are classified into different degrees of intra-abdominal hypertension and, in the presence of associated organ failure, as abdominal compartment syndrome. Both disease entities represent an underestimated factor in intensive care patients and are associated with increased mortality and prolonged intensive care and hospital stay. The measurement of intra-abdominal pressure in critically ill patients in intensive care units is not widely established and there is often considerable uncertainty regarding measurement conditions and methods. If risk factors are present, intra-abdominal pressure should be monitored every 4 hours. Bladder pressure measurement is the gold standard for determining intra-abdominal pressure. The measurement is a non-invasive, cost-effective, easy to perform bedside and safe method for the patient.

Abdominal compartment syndrome (ACS) develops when organ failure arises secondary to an increase in intraabdominal pressure. The abdominal pressure is determined by multiple factors such as blood pressure, abdominal compliance, and other factors that exert a constant pressure within the abdominal cavity. Several conditions in the critically ill may increase abdominal pressure compromising organ perfusion that may lead to renal and respiratory dysfunction. Among surgical and trauma patients, aggressive fluid resuscitation is the most commonly reported risk factor to develop ACS. Other conditions that have also been identified as risk factors are ascites, hemoperitoneum, bowel distention, and large tumors. All patients with abdominal trauma possess a higher risk of developing intra-abdominal hypertension (IAH). Certain surgical interventions are reported to have a higher risk to develop IAH such as damage control surgery, abdominal aortic aneurysm repair, and liver transplantation among others. Close monitoring of organ function and intra-abdominal pressure (IAP) allows clinicians to diagnose ACS rapidly and intervene with target-specific management to reduce IAP. Surgical decompression followed by temporary abdominal closure should be considered in all patients with signs of organ dysfunction. There is still a great need for more studies to determine the adequate timing for interventions to improve patient outcomes.

This review presents an overview of previously reported non-invasive intra-abdominal pressure (IAP) measurement techniques. Each section covers the basic physical principles and methodology of the various measurement techniques, the experimental results, and the advantages and disadvantages of each method. The most promising non-invasive methods for IAP measurement are microwave reflectometry and ultrasound assessment, in combination with an applied external force.

Acute pancreatitis can usually recover after conservative treatment. Five to 10 percent of acute pancreatitis may proceed into peripancreatic fluid collection and necrosis development, called necrotizing pancreatitis (NP), which has a high mortality rate. If it is accompanied by the occurrence of abdominal compartment syndrome (ACS) and does not respond to medical therapy, surgical intervention is indicated.

We analyzed our experience of surgical intervention strategies for NP patients with medically irreversible ACS from January 1, 2004, to December 31, 2018.

Of the 47 NP patients with ACS, mean Ranson score was 6.5, mean Acute Physiology and Chronic Health Evaluation II score was 22.2, and Modified computed tomography severity index score was all 8 or greater. The mean total postoperative hospital length of stay was 80.2 days, of which the mean intensive care unit length of stay was 16.6 days. The overall complication rate was 31.9%. The mortality rate was 8.5%. Among the 47 patients, only fungemia was significantly associated with mortality incidence.

The combination of multiple drainage tube placement, feeding jejunostomy, and ileostomy at the same time were effective surgical intervention strategies for NP patients with ACS, which brought a lower mortality rate.

To evaluate the effect of changes in intra-abdominal pressure (IAP) on medial saphenous venous pressure (MSVP) and hemodynamics in normal horses.

Experimental, in-vivo study.

University Teaching Hospital.

Convenience sample of 7 mixed breed horses; 5 geldings, and 2 mares.

Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intra-abdominal hypertension. The MSVP and vital parameters were recorded, along with direct arterial blood pressure from the transverse facial artery.

As IAP increased, MSVP increased in a stepwise manner, in concert with changes in IAP. The consistency in measurement between MSVP and IAP was high (intraclass correlation coefficient = 0.92; P < 0.001) and repeated measures correlation was excellent (r = 0.98; P < 0.001). Heart rate was unchanged over the course of the experiment (P = 0.09), however, respiratory rate increased with increasing IAP (P < 0.001). Arterial blood pressure also increased with insufflation (P < 0.001), with a significant difference at an IAP of 15 mm Hg (P = 0.04).

This report provides preliminary data demonstrating a strong correlation between equine MSVP and changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this relationship, and to confirm these results in clinical patients.

Abdominal compartment syndrome is a potentially deadly condition that can be missed in the emergency department setting.

The purpose of this narrative review article is to provide a summary of the background, pathophysiology, diagnosis, and management of abdominal compartment syndrome with a focus on emergency clinicians.

Abdominal compartment syndrome is caused by excessive pressure within the abdominal compartment due to diminished abdominal wall compliance, increased intraluminal contents, increased abdominal contents, or capillary leak/fluid resuscitation. History and physical examination are insufficient in isolation, and the gold standard is intra-abdominal pressure measurement. Abdominal compartment syndrome is defined as an intra-abdominal pressure >20 mm Hg with evidence of end-organ injury. Management involves increasing abdominal wall compliance (e.g., analgesia, sedation, and neuromuscular blocking agents), evacuating gastrointestinal contents (e.g., nasogastric tubes, rectal tubes, and prokinetic agents), avoiding excessive fluid resuscitation, draining intraperitoneal contents (e.g., percutaneous drain), and decompressive laparotomy in select cases. Patients are critically ill and often require admission to a critical care unit.

Abdominal compartment syndrome is an increasingly recognized condition with the potential for significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the diagnosis, management, and disposition of these patients.

Intra-abdominal hypertension jeopardizes abdominal organ perfusion and venous return. Contemporary recognition of elevated intra-abdominal pressure (IAP) plays a crucial role in reducing mortality and morbidity. We evaluated ultrasound-guided tonometry in this context hypothesizing that the vertical chamber diameter of this device inversely correlates with IAP.

IAP was increased in six 5 mmHg steps to 40 mmHg by instillation of normal saline into the peritoneal cavity of eight anesthetized pigs. Liver and renal blood flows (ultrasound transit time), intravesical, intraperitoneal, and end-inspiratory plateau pressures were recorded. For ultrasound-based assessment of IAP (ultrasound-guided tonometry), a pressure-transducing, compressible chamber was fixed at the tip of a linear ultrasound probe, and the system was applied on the abdominal wall using different predetermined levels of external pressure. At each IAP level (reference: intravesical pressure), two investigators measured the vertical diameter of this chamber.

All abdominal flows decreased (by 39%-58%), and end-inspiratory plateau pressure increased from 15 mbar (14-17 mbar) to 38 mbar (33-42 mbar) (median, range) with increasing IAP (all P < 0.01). Vertical chamber diameter decreased from 14.9 (14.6-15.2) mm to12.8 (12.4-13.4) mm with increasing IAP. Coefficients of variations between and within observers regarding change of the vertical tonometry chamber diameter were small (all <4%), and the results were independent of the externally applied pressure level on the ultrasound probe. Correlation of IAP and vertical pressure chamber distance was highly significant (r = -1, P = 0.0004). Ultrasound-guided tonometry could discriminate between normal (baseline) pressure and 15 mmHg, between 15 and 25 mmHg) and between 25 and 40 mmHg IAP (all P ≤ 0.18). Similar results were obtained for end-inspiratory plateau pressures.

In our model, values obtained by ultrasound-guided tonometry correlated significantly with IAPs. The method was able to discriminate between normal, moderately, and markedly increased IAP values.

Mesh fixation in hernia repair is currently based on penetrating sutures or anchors, with proven early and late complications such as pain, adhesions, erosions, and anchor migration. In an attempt to reduce these complications, a bio-adhesive-based self-fixation system was developed. The purpose of this study was to assess the performance and safety of this novel self-adhesive mesh (LifeMesh™) by comparing it with standard tack fixation.

A full-thickness abdominal wall defect was created bilaterally in 24 pigs. The defects were measured 14 days later, and laparoscopic intraperitoneal onlay mesh (IPOM) repairs were performed. In each animal, both LifeMesh and a titanium tack-fixed control, either uncoated polypropylene mesh (PP) or composite mesh (Symbotex™), were used. After 28 and 90 days, we performed macroscopic evaluation and analyzed the fixation strength, shrinkage, adhesion scores, and histopathology in all samples.

Measurements at both time points revealed that LifeMesh had fully conformed to the abdominal wall, and that its fixation strength was superior to that of the tack-fixated Symbotex and comparable to that of the tack-fixated PP. Shrinkage in all groups was similar. Adhesion scores with LifeMesh were lower than with PP and comparable with Symbotex at both time points. Histology demonstrated similar tissue responses in LifeMesh and Symbotex. Lack of necrosis, mineralization, or exuberant inflammatory reaction in all three groups pointed to their good progressive integration of the mesh to the abdominal wall. By 28 days the bio-adhesive layer in LifeMesh was substantially degraded, allowing a gradual tissue ingrowth that became the main fixation mode of this mesh to the abdominal wall.

The excellent incorporation of LifeMesh to the abdominal wall and its superior fixation strength, together with its low adhesion score, suggest that LifeMesh may become a preferred alternative for abdominal wall repair.

Introduction. Intra-abdominal pressure (IAP) measurement is an indispensable tool for the diagnosis of abdominal hypertension. Different techniques have been described in the literature and applied in the clinical setting. Methods. A porcine model was created to simulate an abdominal compartment syndrome ranging from baseline IAP to 30 mmHg. Three different measurement techniques were applied, comprising telemetric piezoresistive probes at two different sites (epigastric and pelvic) for direct pressure measurement and intragastric and intravesical probes for indirect measurement. Results. The mean difference between the invasive IAP measurements using telemetric pressure probes and the IVP measurements was -0.58 mmHg. The bias between the invasive IAP measurements and the IGP measurements was 3.8 mmHg. Compared to the realistic results of the intraperitoneal and intravesical measurements, the intragastric data showed a strong tendency towards decreased values. The hydrostatic character of the IAP was eliminated at high-pressure levels. Conclusion. We conclude that intragastric pressure measurement is potentially hazardous and might lead to inaccurately low intra-abdominal pressure values. This may result in missed diagnosis of elevated abdominal pressure or even ACS. The intravesical measurements showed the most accurate values during baseline pressure and both high-pressure plateaus.

Current treatment of the abdominal compartment syndrome (ACS) is based on consensus definitions but several questions regarding fluid regime or critical level of intra-abdominal hypertension (IAH)) remain unsolved. It is questionable whether these issues can be addressed in prospective randomized trials in the near future. This review aimed to summarize current animal models and to outline requirements for the best model.

PubMed® data base was searched for articles describing animal models of ACS.

25 articles were found. ACS in animals has not been defined yet. Investigations varied considerably regarding the experimental design. Animals were rats, rabbits, dogs and pigs with a bodyweight from 200g to 70 kg. IAP increase varied from 20 to 50 mmHg. The time period of IAH ranged between 30 min and 24h. The time between the IAH insult and organ dysfunction varied between 15 min and 18h. Investigations demonstrated that IAH is able to induce loss of intravascular volume, organ hypoperfusion, ischemic organ damage and multiple organ failure within 4 to 6h.

In contrast to IAH or pneumoperitoneum for surgical exposure, ACS in an animal may be stated if an artificially increased IAP leads to circulatory, respiratory and renal insufficiency. A next step in animal research would be the development of a "pathological" model in which haemorrhage or systemic inflammation together with resuscitation lead to abdominal fluid accumulation and increased intra-abdominal pressure.

A standardized large animal model for controlled ICP manipulation within a relevant range and repetitive ICP measurements is missing. We sought to develop such a model on the base of controlled IPP changes induced by capnoperitoneum.

We utilized six female pigs (mean body weight 59.5 ± 18.4 kg) for experiments. A ventricular catheter connected with a burr hole reservoir was implanted. ICP was measured directly as cm H2O within a riser tube after percutaneous cannulation of the reservoir. A noninvasive intraperitoneal pressure (IPP) measurement was established (intravesical). Animals were placed in lateral position and a capnoperitoneum was induced. Measurements of ICP, IPP, MAP and respiratory parameters were performed at baseline IPP and after CO2 insufflation to IPP levels of 20 and 30 mmHg.

Baseline IPP in lateral position referenced to median line was 9.8 (±2) mm Hg, while corresponding ICP was 10 (±2.2) mm Hg. After IPP elevation to 20 mmHg, ICP increased to 18.8 (±1.9) mm Hg. At 30 mmHg IPP, ICP increased to 22.8 (±2.8) mm Hg. Except peak airway pressure, all other parameters were kept constantly. Mean ICP variation in the individual subject was 13.4 (±2.5) mm Hg, while a ICP range from minimum 9 to maximum 31 mmHg was documented.

We report a large animal model that allows (1) repeated measurement of the ICP and (2) manipulation of the ICP within a large pressure range by controlled IPP changes due to capnoperitoneum.

To review and summarize the human and veterinary literature on intra-abdominal pressure measurement techniques.

Human and veterinary clinical studies, research articles, reviews, and textbooks with no date restrictions with a focus on techniques for intra-abdominal pressure (IAP) measurement and their limitations.

Human literature has established the intravesicular method as the gold standard for indirect measurement of IAP. However, current research has explored the intragastric method as a valid alternative. Recently, debate has focused on the shortcomings of the various measurement methods.

Early human literature using dogs as models contributed to the original data for IAP measurements in small animals. Since that time, a number of clinical studies and 1 case report have contributed to that original information. A reference interval for IAP measured by the intravesicular method has recently been determined in healthy cats.

Further studies investigating IAP in critically ill veterinary patients are required to establish the optimal technique for this measurement in veterinary medicine.

The aim of this study was to evaluate microdialysis of the rectus abdominis muscle (RAM) for early detection of subclinical organ dysfunction in a porcine model of critical intra-abdominal hypertension (IAH). Microdialysis catheters for analyses of lactate, pyruvate, and glycerol levels were placed in cervical muscles (control), gastric and jejunal wall, liver, kidney, and RAM of 30 anesthetized mechanically ventilated pigs. Catheters for venous lactate and interleukin 6 samples were placed in the jugular, portal, and femoral vein. Intra-abdominal pressure (IAP) was increased to 20 mmHg (IAH20 group, n = 10) and 30 mmHg (IAH30, n = 10) for 6 h by controlled CO2 insufflation, whereas sham animals (n = 10) exhibited a physiological IAP. In contrast to 20 mmHg, an IAH of 30 mmHg induced pathophysiological alterations consistent with an abdominal compartment syndrome. Microdialysis showed significant increase in the lactate/pyruvate ratio in the RAM of the IAH20 group after 6 h. In the IAH30 group, the strongest increase in lactate/pyruvate ratio was detected in the RAM and less pronounced in the liver and gastric wall. Glycerol increased in the RAM only. After 6 h, there was a significant increase in venous interleukin 6 of the IAH30 group compared with baseline. Venous lactate was increased compared with baseline and shams in the femoral vein of the IAH30 group only. Intra-abdominal pressure-induced ischemic metabolic changes are detected more rapidly and pronounced by microdialysis of the RAM when compared with intra-abdominal organs. Thus, the RAM represents an important and easily accessible site for the early detection of subclinical organ dysfunction during critical IAH.

Intra-abdominal hypertension and abdominal compartment syndrome (ACS) have become key players in increasing mortality among critically ill trauma patients. Many risk factors place the trauma patient at risk for developing ACS. Very few studies exist to establish a predictive relationship between any one risk factor and mortality among these patients. A retrospective, nonexperimental, descriptive project considering preidentified risk factors and their direct association with mortality in patients exhibiting intra-abdominal hypertension and ACS was carried out in an urban level 1 trauma center. Polytransfusion was strongly predicted among those with ACS for mortality (P < .001). Mortality was strongly associated with a reported history of diabetes (P < .05). The total amount of blood products showed a perfect correlation with death as well (r = 1.0, P < .001).

Pneumoperitoneum and patient positioning are essential factors during laparoscopic surgical procedures. They cause hemodynamic and anatomical changes in several abdominal organs among which the caudal cava vein (CCV) is involved. Hemodynamic changes in this vein (decreased venous return) have been described in the porcine model, but how the vein morphology and size is affected at different abdominal levels is unknown. We sought to assess the morphological and morphometrical changes in the CCV of the pig caused by pneumoperitoneum and the reverse Trendelenburg position by in vivo magnetic resonance imaging (MRI).

Six pigs were scanned via MRI under four situations: S1, control (no pneumoperitoneum); S2, control in the reverse Trendelenburg position; S3, pneumoperitoneum (14 mmHg); and S4, pneumoperitoneum in the reverse Trendelenburg position. MRI and plastinated body sections were used to evaluate the topography, morphology and cross-sectional area of the CCV.

Two portions of the CCV were differentiated: a prehepatic portion (located between the vertebral levels L1-T15) with flat and irregular morphology, and a hepatic portion (between T14-T11) that was almost rounded. The reverse Trendelenburg position caused an increase in the lumen affecting mainly the prehepatic portion, while pneumoperitoneum caused a decrease in the total vascular lumen, exerting a greater effect on the hepatic portion. The combination of both situations resulted in a further decrease in the vascular area and global morphological changes.

The pneumoperitoneum and reverse Trendelenburg position caused morphological and morphometrical changes in the prehepatic and hepatic portions of the CCV, which should assist in gaining a better understanding of the hemodynamic changes described in the literature.

The purpose of the present study was to quantify bacterial translocation to mesenteric lymph nodes due to different levels of intra-abdominal hypertension (IAH; 15 vs. 30 mmHg) lasting for 24 h in a porcine model.

We examined 18 anesthetized and intubated pigs (52.3 ± 4.7 kg) which were randomly allocated to three experimental groups (each n = 6) and studied over a period of 24 h. After preparation and establishing a steady state, the intra-abdominal pressure (IAP) was increased stepwise to 30 mmHg in six animals using a carbon dioxide (CO2) insufflator (IAP-30 group). In the second group, IAP was increased to 15 mmHg (IAP-15 group), while IAP remained unchanged in another six pigs (control group). Using a pulse contour cardiac output (PiCCO®) monitoring system, hemodynamic parameters as well as blood gases were recorded periodically. Moreover, peripheral and portal vein blood samples were taken for microbiological examinations. Lymph nodes from the ileocecal junction were sampled during an intra-vital laparotomy at the end of the observational period. After sacrificing the animals, bowel tissue samples and corresponding mesenteric lymph nodes (MLN) were extracted for histopathological and microbiological analyses.

Cardiac output decreased in all groups. In IAP-30 animals, volumetric preload indices significantly decreased, while those of IAP-15 pigs did not differ from those of controls. Under IAH, the mean arterial pressure (MAP) in the IAP-30 group declined, while MAP in the IAP-15 group was significantly elevated (controls unchanged). PO2 and PCO2 remained unchanged. The grade of ischemic damage of the intestines (histopathologically quantified using the Park score) increased significantly with different IAH levels. Accordingly, the amount of translocated bacteria in intestinal wall specimens as well as in MLN significantly increased with the level of IAH. Lymph node cultures confirmed the relation between bacterial translocation (BT) and IAP. The most often cultivated species were Escherichia coli, Staphylococcus, Clostridium, Pasteurella, and Streptococcus. Bacteremia was detected only occasionally in all three groups (not significantly different) showing gut-derived bacteria such as Proteus, Klebsiella, and E. coli spp.

In this porcine model, a higher level of ischemic damage and more BT were observed in animals subjected to an IAP of 30 mmHg when compared to animals subjected to an IAP of 15 mmHg or controls.

The aim of this study was to determine whether intra-abdominal pressure (IAP) monitoring using the FoleyManometer (Holtech Medical, Charlottenlund, Denmark) increases the risk of urinary tract infection (UTI).

A retrospective database review was conducted.

The study was conducted in the 12-bed medical intensive care unit of ZNA Stuivenberg Hospital (Antwerp, Belgium), a tertiary hospital.

There were 5,890 patients admitted to the medical intensive care unit of which 1,097 patients underwent intrabladder pressure (IBP) monitoring as estimate for IAP.

Crude and adjusted UTI rates were compared among patients undergoing IAP measurements with three different intrabladder methods: a modified homemade technique, a FoleyManometer with 35 ml reservoir, and a FoleyManometer low volume (FoleyManometerLV) with less than 10 ml priming volume.

Four consecutive time periods of 24 months were defined and compared with regard to IAP measurement: period 1 (2000-2001), during which IAP monitoring was not used routinely (which serves as a control group), was compared with period 2 (2002-2003), using a modified homemade technique; period 3 (2004-2005), introducing the FoleyManometer; and finally period 4 (2006-2007), in which the FoleyManometerLV was introduced. The incidence of IBP measurements increased from 1.4% in period 1 to 45.4% in period 4 (p < 0.001). At the same time, the Simplified Acute Physiology Score (version 2) (SAPS-II) increased significantly from 24.4 ± 21.5 to 34.9 ± 18.7 (p < 0.001) together with the percentage of ventilated patients from 18.6% to 40.7% (p < 0.001). In total, 1,097 patients had IAP measurements via the bladder. The UTI rates were adjusted for disease severity by multiplying each crude rate with the ratio of control versus study patient SAPS-II probability of mortality. Crude and adjusted UTI rates per 1,000 catheter days (CD) were on average 16.1 and 12.8/1,000 CD, respectively, and were not significantly different between the four time periods.

Intrabladder pressure monitoring as estimate for IAP either via a closed transducer technique or the closed FoleyManometer technique seems safe and does not alter the risk of UTI in critically ill patients.

To (1) evaluate intra-abdominal pressure (IAP) measurements in dogs with possible risk factors for the development of intra-abdominal hypertension (IAH); (2) determine intra-observer variability of IAP measurements; and (3) determine interobserver variability of IAP measurements.

Prospective, observational, pilot study.

Veterinary teaching hospital.

Fourteen client-owned dogs, requiring urinary catheterization, admitted to the ICU.

Using the risk factors for IAH established for human patients as defined by the World Society of Abdominal Compartment Syndrome, dogs were assigned to either an IAH risk or no risk group. A commercially available IAP monitoring system was used to obtain 3 direct, transvesical IAP measurements. The primary investigator obtained the first 2 IAP measurements. A secondary investigator obtained the third IAP measurement.

Dogs in the IAH risk group (n = 9/14) had significantly higher mean IAPs (9.4 ± 3.4 mm Hg) than dogs in the no risk group (n = 5/14; 4.1 ± 0.9 mm Hg) (P < 0.05). Measurements recorded by the primary investigator were compared to determine intra-observer variability. Pearson's correlation coefficient was 0.98 (P < 0.0001). Bland-Altman analysis determined a mean difference in IAP measurements of -0.3 mm Hg (95% confidence interval from 0.13 to -0.71 mm Hg) indicating an intra-observer variability of less than 0.8 mm Hg. Measurements recorded by the primary and secondary investigator were compared to determine interobserver variability. Pearson's correlation coefficient was 0.95 (P < 0.0001). Bland-Altman analysis determined a mean difference in IAP measurements of 0 mm Hg (95% confidence interval from 1.1 to -1.1 mm Hg) indicating an interobserver variability of less than 2.0 mm Hg.

Dogs with predefined human risk factors for IAH had higher IAP than dogs without risk factors. IAP monitoring appears to have low variability within and across observers.

Background. Intravesical pressure (IAP(ivp)) measurement is considered to be the gold standard for assessment of intra-abdominal pressure (IAP). This study evaluated a new minimally invasive IAP monitoring device (CiMON) against three other devices in a wide range of clinically relevant IAP and in different body positions in healthy pigs. Methods. The CiMON catheter (IAP(CiM)) and another balloon-tipped catheter (IAP(spie)) were positioned into the stomach. Fluid-filled catheters were used for direct intraperitoneal (IAP(dir)) and IAP(ivp) measurement. Both in supine and 25° head-of-bed positions, IAP was increased from baseline to 30 mmHg. At every IAP level, 4 IAP measurements were recorded simultaneously. Mean differences and the limits of agreement were calculated. Results. Bias between IAP(CiM) and IAP(spie) was nearly zero with very good agreement, both in supine and 25° position. In supine position, IAP(CiM) slightly overestimated IAP(ivp) and IAP(dir) by 1.5 and 2.1 mmHg with reasonable agreement. In 25° position, IAP(CiM) underestimated IAP(ivp) and IAP(dir) by 1.0 and 0.5 mmHg, again with reasonable agreement. Conclusions. Agreement between IAP(CiM) and IAP(spie) was very good, while good-to-moderate agreement exists between IAP(CiM) and IAP(dir) or IAP(ivp). Simplicity, continuous monitoring, and the combination with a feeding tube should lead to further clinical studies, evaluating this new CiMON device.

To investigate if femoral venous pressure (FVP) measurement can be used as a surrogate measure for intra-abdominal pressure (IAP) via the bladder.

This was a prospective, multicenter observational study. IAP and FVP were simultaneously measured in 149 patients. The effect of BMI on IAP was investigated.

The incidences of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) were 58 and 7% respectively. The mean APACHE II score was 22 ± 10, SAPS 2 score 42 ± 20, and SOFA score 9 ± 4. The mean IAP was 11.2 ± 4.5 mmHg versus 12.7 ± 4.7 mmHg for FVP. The bias and precision for all measurements were -1.5 and 3.6 mmHg respectively with the lower and upper limits of agreement being -8.6 and 5.7. When IAP was above 20 mmHg, the bias between IAP and FVP was 0.7 with a precision of 2.0 mmHg (lower and upper limits of agreement -3 and 4.6 respectively). Excluding those with ACS, according to the receiver operating curve analysis FVP = 11.5 mmHg predicted IAH with a sensitivity and specificity of 84.8 and 67.0% (AUC of 0.83 (95% CI 0.81-0.86) with P < 0.001). FVP = 14.5 mmHg predicted IAP above 20 mmHg with a sensitivity of 91.3% and specificity of 68.1% (AUC 0.85 (95% CI 0.79-0.91), P < 0.001). Finally, at study entry, the mean IAP in patients with a BMI less then 30 kg/m(2) was 10.6 ± 4.0 mmHg versus 13.8 ± 3.8 mmHg in patients with a BMI ≥ 30 kg/m(2) (P < 0.001).

FVP cannot be used as a surrogate measure of IAP unless IAP is above 20 mmHg.

A 30° head-of-bed elevation is recommended for most critically ill patients. Measuring intrabladder pressure with the patient in this position is controversial.

To assess the feasibility of measuring intrabladder pressure with a 30° head-of-bed elevation.

A prospective, randomized, and experimental study. Patients had intrabladder pressure measured first while positioned supine with a 30° head-of-bed elevation and 25 mL of saline instilled into the bladder and again after the patients were randomly repositioned to supine without any head-of-bed elevation (flat) or with a 30° head-of-bed elevation while supine or in right lateral or left lateral position with either 25, 50, or 200 mL of saline instilled into the patient's bladder.

Intrabladder pressures measured with the patient in all 3 head-of-bed elevated positions were higher than pressures measured with patients supine and flat after instillation of 25 mL of saline into the bladder, but intrabladder pressure did not differ between the 30° head-of-bed elevated positions and the supine and flat positions when 50 or 200 mL of saline was instilled into the bladder. Two-way analysis of variance showed a significant interaction between volume of saline instilled (P = .05), patient's position (P = .007), and bladder instill volume and position interaction (P = .004).

It is feasible to measure intrabladder pressure with a 30° head-of-bed elevation, and that position could be an alternative to supine positioning of patients for measurement of intrabladder pressure.

We sought to establish normative values of intraabdominal pressure (IAP) in postpartum women with and without arterial hypertension.

Bladder pressure was measured via a Foley catheter 1 hour following completion of cesarean section in supine and semirecumbent positions in 21 patients.

Mean supine IAP (6.4 +/- 5.2 mm Hg) was significantly lower than semirecumbent IAP (11.6 +/- 7.2 mm Hg) (P < .05). Body mass index (BMI) was significantly correlated to IAP regardless of the gestational age (r(2) supine = 0.46, semirecumbent = 0.37; P = .004 for either). Increasing gravidity was associated with decreasing IAP. Patients with arterial hypertension had higher BMI, were delivered earlier, and had higher IAP than patients with normal arterial pressure, either in supine or semirecumbent position. However, these relationships were not significant when results were controlled for BMI.

Postcesarean section IAP is higher than in the general surgical population. Patients with hypertensive disorders have IAPs approaching to intraabdominal hypertension range.

Intra-organ and intra-vascular pressures can be used to estimate intra-abdominal pressure. The aim of this prospective, interventional study was to assess the effect of PEEP on the accuracy of pressure estimation at different measurement sites in a model of increased abdominal pressure.

Catheters for pressure measurement were inserted into the stomach, urinary bladder, peritoneal cavity, pulmonary artery and inferior vena cava of 12 pigs. The pressures were recorded simultaneously at baseline, during 10 cm H20 PEEP, external abdominal pressure (7 kg weight) plus PEEP, external abdominal pressure without PEEP, and again under baseline conditions. RESULTS (MEAN +/- SD): PEEP alone increased diastolic pulmonary artery and inferior vena cava pressure but had no effect on the other pressures. PEEP and external abdominal pressure increased intraperitoneal pressure from 6 +/- 1 mm Hg to 9 +/- 2 mm Hg, urinary bladder pressure from 6 +/- 2 mm Hg to 11 +/- 2 mm Hg (p = 0.012), intragastric pressure from 6 +/- 2 mm Hg to 11 +/- 2 mm Hg (all p

CONCLUSIONS

Our data suggest that pressure changes induced by external abdominal pressure were not modified by changing PEEP between 0 and 10 cm H20.

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Patient position and body mass index (BMI) affect intra-abdominal pressure (IAP) measured by the intra-vesical method in adults. We sought to determine effects of patient position and BMI on IAP in children because accurate measurement and interpretation of IAP are important for patient management.

Seventy-seven mechanically ventilated children (<18 years) admitted to a PICU were prospectively studied. IAP was taken with the head of the bed at 0 degrees and 30 degrees every 6 h over a 24-h period. Statistical methods included descriptives, univariate statistics to identify potential confounding variables and multivariable analysis to assess the impact of position on IAP after adjusting for the significant covariates.

Seventy-seven patients had 290-paired IAP measurements. Mean IAP at 30 degrees was 10.6 +/- 4.0 compared to 8.4 +/- 4.0 at 0 degrees , which was significantly higher (p = 0.026) even after adjusting for age, gender and length. There was no correlation between IAP and actual BMI or BMI percentiles.

Patient position should be considered when interpreting IAP. BMI did not influence IAP measurements in children.

In patients after surgery, we observed large-amplitude low-frequency changes in digital plethysmograph measurements when DC coupling of the signal was used. We set out to assess factors that might contribute to these events and in particular to test the possibility that low-frequency signals could be used to assess respiratory disturbances.

We recorded values in 23 patients who had undergone gynaecological surgery. We measured nasal flow, abdominal pressure (by urinary catheter), venous pressure in the hand, and DC-coupled optical transmission plethysmography. Signals were replayed and analysed to assess the incidence of specific patterns of events.

Most patients received morphine for postoperative analgesia. Respiratory irregularity and expiratory muscle action were very frequent. Increases in abdominal pressure during expiration caused increases in venous pressure and pulsation. In 12 out of 23 patients, a characteristic response consistent with vasoconstriction was noted after increases in breath size, and, in seven patients, very-low-frequency (0.2-0.7 Hz) oscillations of finger volume were present that appeared unrelated to respiratory events. Patients who did not receive morphine had very different plethysmograph patterns, with significantly smaller pulse amplitude.

Low-frequency changes in finger volume can be simply obtained and provide considerable information about peripheral circulatory dynamics. Diverse patterns can be recognized, but the range of responses suggests that current techniques cannot be used alone to assess cardiorespiratory status. However, a combination of plethysmography with respiratory measurements shows characteristic events.

The abdominal compartment syndrome (ACS) is associated with organ dysfunction and mortality in critically ill patients. Furthermore, the deleterious effects of increased IAP have been shown to occur at levels of intra-abdominal pressure (IAP) previously deemed to be safe. The aim of this article is to provide an overview of all aspects of this underrecognized pathological syndrome for surgeons.

This review article will focus primarily on the recent literature on ACS as well as the definitions and recommendations published by the World Society for the Abdominal Compartment Syndrome. The definitions regarding increased IAP will be listed, followed by a brief but comprehensive overview of the different mechanisms of organ dysfunction associated with intra-abdominal hypertension (IAH). Measurement techniques for IAP will be discussed, as well as recommendations for organ function support in patients with IAH. Finally, surgical treatment and management of the open abdomen are briefly discussed, as well as some minimally invasive techniques to decrease IAP.

The ACS was first described in surgical patients with abdominal trauma, bleeding, or infection, but in recent years ACS has also been described in patients with other pathologies such as burn injury and sepsis. Some of these so-called nonsurgical patients will require surgery to treat their ACS. This review article is intended to provide surgeons with a clear insight into the current state of knowledge regarding IAH, ACS, and the impact of IAP on the critically ill patient.

Two cases of chronic abdominal hypertension in pseudo-Meigs' syndrome, one sustained by a large ovarian bilateral carcinoma and the other by a giant genital angiomyolipoma, are reported.

Both patients presented to the emergency room for abdominal distention and pain with progressive respiratory dysfunction, hypotension over several days, and early symptoms of renal failure, together suggestive of chronic, intra-abdominal hypertension.

Intra-abdominal hypertension and abdominal compartment syndrome are serious conditions which may complicate large tumors and tense ascites, apart from their benign or malignant nature. The chronic development of abdominal hypertension and onset of the abdominal compartment syndrome associated with Meigs' syndrome must be recognized in a timely manner and promptly treated by performing as complete a resection of the pelvic mass as possible; alternatively, in acute abdominal hypertension the monitoring of bladder pressure can evaluate the effectiveness of medical therapy and determine the optimal timing of decompressive laparotomy in case of the abdominal compartment syndrome.