Intra-abdominal Pressure Measurement Research Articles

Effect of patient positioning on intra-abdominal pressure monitoring

Background Intra-abdominal hypertension affects multiple organ systems. Current measurement standard requires supine positioning, which jeopardizes patient safety by increasing the risk for ventilator-associated pneumonia. This study evaluated the relationship between intra-abdominal pressure (IAP) and head-of-bed (HOB) positioning in critically ill intubated patients. Methods IAP measurements were performed using intravesical catheters with manometry. IAP was measured in a range of patient HOB increases from 0° to 45°. Multivariable generalized estimating equation modeling was performed to describe the relationship between IAP and HOB positioning. Results Three hundred (300) observations were performed on 37 patients. In multivariable modeling, HOB increase was significantly associated with IAP. Body mass index, positive end-expiratory pressure, temperature, and diagnostic category were significant in this model, whereas age and Riker sedation score were not. Conclusions There is a significant, positive association between IAP and HOB positioning in critically ill patients. Clinically relevant changes in IAP occur at HOB increases >20°.

Intra-abdominal pressure measurement: validation of intragastric pressure as a measure of intra-abdominal pressure

The diagnosis of abdominal compartment syndrome depends upon the demonstration of an elevated intra-abdominal pressure (IAP). Direct measures of IAP are impractical in the critical care unit; intravesical pressure (IVP) and intragastric pressure (IGP) should represent acceptable surrogate measures. IVP is the preferred measure of IAP in critical care. We considered that IGP represents a practical alternative. The objective of this preliminary study was to observe the relationship between IGP and IAP. After Institutional Ethics Board approval, 29 patients having elective laparoscopic surgery were recruited. IAP was measured directly via the abdominal trochar. This was compared with IGP measured via a commercial balloon catheter placed into the stomach. Measured IGP was always more positive than IAP; both showed linear correlation (r2>0.9). When IGP was calibrated against IAP, an estimated difference between the IGP and IAP of+/-2.5 mm Hg for 95% of the measurements was seen. The study demonstrates the strength of the relationship between IGP and IAP in normal individuals. Application of IGP measurement in the critical care patient is necessary to demonstrate its suitability for continuous IAP assessment.

Intra-abdominal pressure measurement and abdominal compartment syndrome: The opinion of the World Society of the Abdominal Compartment Syndrome

Critical Care Medicine: February 2007 - Volume 35 - Issue 2 - p 678-679 doi: 10.1097/01.CCM.0000254053.14101.D8

Intra-abdominal pressure measurement and abdominal compartment syndrome: The opinion of the World Society of the Abdominal Compartment Syndrome

Intra-abdominal pressure measurement and abdominal compartment syndrome: The opinion of the World Society of the Abdominal Compartment Syndrome

RATIONAL INTRAABDOMINAL PRESSURE MONITORING: HOW TO DO IT?

Introduction: Intraabdominal hypertension (IAH) is increasingly appreciated by intensivists as an important cause of organ dysfunction, even at pressure levels which were previously thought to be harmless. Therefore, the goal of this review is to describe the different methods commonly used in clinical practice for intraabdominal pressure (IAP) measurement, the advised methodology for each measurement method, and finally to give a rational approach for IAP monitoring in daily clinical practice.Methods: A Medline search of the English literature was performed using the term “intra abdominal pressure” and “measurement”. This resulted in 194 studies, which were then analysed based on the title and abstract. Only clinical studies in human subjects with IAP measurement or related issues as the subject of the study, were considered for inclusion in the study. Reviews, animal experiments and case reports were excluded, while one specific review on IAP measurement and 3 large animal studies (domestic swine > 40 kg) were included in the analysis. This left us with 19 studies, published between 1984 and 2006: 1 specific review, 2 studies in children, 13 in adults and 3 in domestic swine. The references from these studies were searched for relevant articles that may have been missed in the primary search. These articles served as the basis for the recommendations below.Results: Clinical data regarding the validation of new IAP measurement methods or the reliability of established measurement techniques are scarce. The transvesical route, which has been studied most extensively, can be used as reliable route for intermittent IAP measurement, as long as instillation volumes below 25mL are used. Continuous IAP and APP monitoring can be done via a balloon-tipped catheter placed in the stomach or directly intraperitoneal.Conclusions: Rational IAP monitoring should be based on a site specific protocol, based on known risk factors, the monitoring equipment available and nursing staff experience, and should be linked directly to a local treatment protocol.

THE SECONDARY AND RECURRENT ABDOMINAL COMPARTMENT SYNDROME

Introduction: The Secondary Abdominal Compartment Syndrome (SACS) refers to cases of the ACS that do not originate from the abdominopelvic region. With greater awareness of the physiologic consequences of raised intra-abdominal hypertension (IAH), cases of the SACS are being increasingly described. The prior treatment or the presence of a partially open abdomen does not preclude the ACS if the abdomen and viscera continue to swell or the clinician is not vigilant in monitoring intra-abdominal pressure (IAP). Such recurrent cases (RACS) have been defined as those which redevelop following the previous medical or surgical treatment of primary or SACS. Although there has been a diverse range of etiologies implicated, these cases seem to be linked by the common occurrence of severe shock requiring aggressive fluid resuscitation. The aim of this paper is to thus to review the historical background, awareness, definitions, pathophysiological implications and treatment options for SACS and RACS.Methods: This review will focus on the available literature regarding SACS and RACS. A Medline and Pubmed search was performed using the keywords; secondary abdominal compartment syndrome AND secondary AND tertiary AND recurrent AND abdominal compartment syndrome AND intra-abdominal pressure AND intra-abdominal hypertension. Bibliographies of recovered papers were hand-searched for other appropriate references. The resulting references were included in the current review on the basis of relevance and scientific meritResults: There has been remarkably little specific study of these entities outside of specific groups such as those injured by thermal or traumatic injury. The epidemiology, risk factors for, treatment of and most importantly, strategies for prevention all remain scientifically unknown and therefore based on opinion. Notable, although small, studies suggest that specific resuscitation practices may avert these conditions.Conclusions: ACS can occur in any patient who is critically ill and subject to visceral and somatic swelling, regardless of whether the inciting pathology is extra-abdominal. The ACS may also reoccur with recurrent shock and swelling even if previous therapies had partially addressed IAH. Therefore IAP measurements should be considered a routine monitoring for the critically ill, especially those subjected to shock and requiring a subsequent resuscitation. Much further study is required to understand the differences in etiology, diagnosis, pathophysiology, and treatment for all cases of the ACS.

NOOSA, 2 YEARS LATER… A CRITICAL ANALYSIS OF RECENT LITERATURE

Introduction: Since the second World Congress on the Abdominal Compartment Syndrome (WCACS) in Noosa 2 years ago, interest and publications on intra-abdominal hypertension (IAH) and ACS have increased exponentially. This paper aimed to critically review recent publications and put this new data into the context of already acquired knowledge concerning IAH/ACS.Methods: A Medline and PubMed search was performed from January 2005 up to now using “intra-abdominal pressure (IAP)”, “intra-abdominal hypertension (IAH)”, “abdominal compartment syndrome (ACS)” and “decompressive laparotomy” as search items.Results: Although consensus definitions of IAH/ACS have been formulated recently, data on awareness are still disconcerting. Several groups refined current IAP measurement techniques and tested new direct IAP measurement devices for use in selected subpopulations. A series of recent publications identified specific patient subpopulations in IAH/ACS, like patients with burns or severe acute pancreatitis, with their specific pathophysiology and therapy. Although many studies already assessed the effect of elevated IAP on regional and micro-circulatory organ perfusion, a number of new publications attempted to unravel the link between elevated IAP and more “downstream” organ function or histology. Finally, therapy for IAH/ACS still reveals more questions than it answers. Global resuscitation does not necessarily equate with organ resuscitation. In fact, fluid-resuscitation may even induce IAH/ACS.Conclusions: After publication of consensus guidelines on IAH/ACS, there is an urgent need for human intervention studies and, in parallel, clinically relevant animal models. Given moderately low incidence of ACS and the complex and interrelated pathologies of the critically ill patient with IAH/ACS, large animal models of pathology-induced IAH/ACS might create the opportunity to gain clinically relevant knowledge on the treatment of IAH/ACS.

CONTINUOUS INTRA-ABDOMINAL PRESSURE MONITORING

Background: Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) can develop within 12 hours of ICU admission in high-risk patients. Until recently the intermittent intra-abdominal pressure (IAP) measurement via the urinary catheter was the clinical standard. This is a relatively labour intensive technique and its intermittent nature could prevent timely recognition of significant changes in IAP. The historical continuous IAP (CIAP) measurements were poorly reproducible (gastric route) or invasive/impractical (direct measurement). The aim of this paper is to review the current evidence on CIAP monitoring.Methods: A broad Medline search of the English literature was performed using the terms of “intra abdominal pressure” and “continuous”. This result was analysed based on the title and abstract. Only original clinical studies with continuous IAP measurement were considered in this review. New techniques of CIAP monitoring evaluated in large animal models are discussed as potential future directions.Results: There is a growing evidence of measuring (monitoring) CIAP using several techniques (gastric, direct abdominal, inferior vena cava, and urinary bladder. The strongest evidence supports the direct abdominal, the gastric and the bladder route. From these three techniques the CIAP monitoring via the bladder has excellent agreement with the current standard of intermittent bladder pressure measurement. While the direct measurement could be very accurate it is an invasive method and feasible in patient who underwent laparotomy or laparoscopy.Conclusions: Until a better technique is available the CIAP monitoring via the bladder or stomach should be considered as the standard for continuous monitoring of the IAP. It is a less labour intensive, safe, less invasive and reliable method.

The real intraabdominal pressure during laparoscopy: Comparison of different insufflators

Study objective To compare 5 laparoscopic insufflators with different gas flow rates with regard to accuracy of preset pressure setting versus real intraoperative intraabdominal pressure. Design Prospective study (Canadian Task Force classification II-2). Setting Fayette Medical Center, Alabama. Patients Five patients undergoing laparoscopic cholecystectomy. Interventions Intraoperative intraabdominal and system pressure measurements during comparable laparoscopic procedures. Measurements and main results Actual intraabdominal pressure was measured and compared between 5 different 10 to 20 L/min insufflators (Storz Laparoflator and Endoflator, Richard Wolf, BEI Medical and Snowden & Pencer) with a computer-based online data acquisition system. At a nominal pressure of 10 mm Hg, the mean intraabdominal pressure during the entire procedure was measured to be between 9.68 and 11.45 mm Hg. The mean intraabdominal pressure during laparoscopy for the insufflators showed a margin of error of 14.5%, with maximum intraabdominal pressure peaks measured between 14.65 and 17.87 mm Hg. Conclusions Within an error margin of <15% of the preset intraabdominal pressure setting, the insufflators evaluated can be considered pressure reliable. Although intraabdominal pressure peaks exceeding the nominal pressure temporarily reached up to 78.7% of the setting, no apparent complications were observed. Excessive pressure peaks seen in the previous reported laboratory model could not be confirmed during in vivo application.

EFFECT OF INTRA-ABDOMINAL PRESSURE ON RESPIRATORY MECHANICS

Introduction: There has been an exponentially increasing interest in intra-abdominal hypertension (IAH). The intra-abdominal pressure (IAP) markedly affects the function of the respiratory system.Methods: This review will focus on the available literature from the past few years. A Medline and Pubmed search was performed in order to find an answer to the question “What is the impact of increased IAP on respiratory function in the critically ill?”.Results: In particular, increased IAP increases chest wall elastance (or decreases compliance) and promotes cranial shift of the diaphragm, with consequent reduction in lung volume and atelectasis formation. Compression of the lung parenchyma also triggers pulmonary infection. During general anaesthesia, in normal subjects, IAP does not affect the chest wall mechanics, but plays a relevant role in the caudal-cranial displacement of the abdominal content, the diaphragm and consequent changes in lung mechanics and function. In obese patients, the increased IAP is the major determinant of the reduction in lung volume, atelectasis formation and alterations in chest wall mechanics. In ARDS patients the measurement of IAP and chest wall mechanics is important for a better interpretation of respiratory mechanics, hemodynamics and appropriate setting of the ventilator. Furthermore, increased IAP promotes lung oedema, ventilator induced lung injury and reduced lymphatic flow in normal and diseased lungs.Conclusion: Increased IAP markedly affects respiratory function in such a way that it has an impact on daily clinical practise.

Continuous intra-abdominal pressure measurement technique

Continuous intra-abdominal pressure measurement technique

Influence of Semi-Recumbent Position on Intra-Abdominal Pressure as Measured by Bladder Pressure

Intra-abdominal pressure (IAP) obtained by bladder pressure measurement is used to detect impending abdominal compartment syndrome (ACS), but, while it is recommended to use a supine position, the literature describes IAP measurement in varying positions. This study evaluated the impact of body position at differing head-of-bed (HOB) elevations on bladder pressure when planned to be used as a surrogate IAP measurement. Forty-five trauma patients admitted to a surgical intensive care unit underwent bladder pressure measurements at 0, 15, 30, 45 degrees HOB position and 30 degrees HOB position plus 15 degrees of reverse Trendelenburg tilt; these measurements were performed in counterbalanced fashion and assessed by built-in angle indicators on the bed rails of each bed. Study participants were connected to an IAP monitoring kit via their indwelling Foley catheter. A total of 675 bladder pressure measurements were obtained with 135 measurements at each of five HOB elevations (0 degrees , 15 degrees , 30 degrees , 45 degrees , 30 degrees +15 degrees tilt). Statistically significant differences occurred between all HOB elevations. Statistically significance differences also occurred at different BMI statuses. Elevating HOB significantly increases bladder pressure measurement. Bladder pressure measurements in nonsupine positions may not provide valid interpretation for IAP, and more so in cases of increased body mass index.

DETERMINING NORMAL VALUES FOR INTRA‐ABDOMINAL PRESSURE

Intra-abdominal pressure (IAP) measurements can be used for the early detection and management of the abdominal compartment syndrome. IAP values are widely thought to be atmospheric or subatmospheric. However, there are no reports that describe normal IAP values using urinary bladder pressure measurements in patients not suspected of having a raised IAP level. This study sought to determine these normal values to aid our interpretation of IAP measurements in post-surgical patients or patients with suspected increased IAP. Urinary bladder pressure measurements were carried out in 40 men and 18 women awake medical or non-abdominal surgery inpatients with existing indwelling catheters. Measurements were made in the supine, 30 degrees and 45 degrees sitting positions. Comparisons were carried out to determine the effects on urinary bladder pressure of body position, sex and a suspected diagnosis of benign prostatic hypertrophy. Median values for IAP were higher if measured in a more upright position (P < 0.0001). Median values were supine, 9.5 cmH2O (range, 1-18 cmH2O); 30 degrees upright, 11.5 cmH2O (range, 3-19 cmH2O); and at 45 degrees upright, 14.0 cmH2O (range, 4-22 cmH2O). Measurements recorded were neither atmospheric nor subatmospheric. IAP was higher in men compared with women in the supine and 30 degrees positions (P < 0.05) but not in the 45 degrees position (P = 0.083). There was no significant difference between patients with and without suspected benign prostatic hypertrophy. Normal IAP using urinary bladder pressure in awake patients are above atmospheric pressure. As a patient is moved from the supine into the upright position, IAP measurements increase.

Intraabdominal Pressure in Abdominoplasty Patients

Abdominal compartment syndrome is directly related to an increase in intraabdominal pressure (IAP), which can lead in severe cases to serious clinical consequences. Routine measurement of IAP in specific cases has been advocated by some surgical specialties. However, few studies in plastic surgery have focused on the use of IAP. The authors review the literature and describe a method of IAP analysis used for 12 patients who underwent abdominoplasty.

New Technique of Direct Intra-abdominal Pressure Measurement

To determine the efficacy of 14-Fr PVC round drain in the direct measurement of intra-abdominal pressure. Fifty consecutive patients undergoing elective laparoscopic surgery in a tertiary teaching hospital were included in this pilot study. Patients underwent laparoscopic cholecystectomy, appendectomy, splenectomy, colectomy and Nissen fundoplication. After creation of pneumoperitoneum and insertion of the trocars as indicated by the operation, a 14-Fr PVC round drain was inserted into the abdominal cavity via one of the laparoscopic ports. It was then connected under sterile conditions to the invasive blood pressure measurement system. Intra-abdominal pressure was gradually increased. Intra-abdominal pressures as measured through the round PVC drain were compared to those measured by the laparoscopic insufflator at 5, 8, 12 and 24 mmHg. Two hundred measurements using each of the two methods were performed and correlated. The correlation coefficient was 0.996. No complications were observed with this new technique. Direct measurement of intra-abdominal pressure using 14-Fr PVC round drain is a newly described technique that is simple, fast and credible. Future investigation will be needed to confirm the reliability of this method during postoperative follow-up of intra-abdominal pressures in selected patients.

Results from the International Conference of Experts on Intra-abdominal Hypertension and Abdominal Compartment Syndrome. I. Definitions

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been increasingly recognized in the critically ill over the past decade. The variety of definitions proposed has led to confusion and difficulty in comparing one study to another. An international consensus group of critical care specialists convened at the second World Congress on Abdominal Compartment Syndrome to standardize definitions for IAH and ACS based upon the current understanding of the pathophysiology surrounding these two syndromes. Prior to the conference the authors developed a blueprint for the various definitions, which was further refined both during and after the conference. The present article serves as the final report of the 2004 International ACS Consensus Definitions Conference and is endorsed by the World Society of Abdominal Compartment Syndrome (WSACS). IAH is redefined as an intra-abdominal pressure (IAP) at or above 12 mmHg. ACS is redefined as an IAP above 20 mmHg with evidence of organ dysfunction/failure. ACS is further classified as either primary, secondary, or recurrent based upon the duration and cause of the IAH-induced organ failure. Standards for IAP monitoring are set forth to facilitate accuracy of IAP measurements from patient to patient. State-of-the-art definitions for IAH and ACS are proposed based upon current medical evidence as well as expert opinion. The WSACS recommends that these definitions be used for future clinical and basic science research. Specific guidelines and recommendations for clinical management of patients with IAH/ACS are published in a separate review.

Intra-abdominal pressure measurement during ultrasound assessment of women with stress urinary incontinence: a novel model

PURPOSE: To determine the influence of intra-abdominal pressure on the ultrasonographic evaluation of the urethrovesical junction (UVJ) and proximal urethra (PU) in women with stress urinary incontinence (SUI). METHODS: This is a prospective cross-sectional study undertaken at the Urinary Incontinence Research Unit (UIRU) of the Universidade Federal de Pernambuco (UFPE). Thirty-six women complaining of SUI underwent perineal ultrasound assessments of the UVJ and PU having the bladder barely empty (&lt; 50 ml of urine) with simultaneous measurement of the intra-abdominal pressure (IAP). An ALOKA ultrasound machine with a 7 MHz vaginal probe was used for the assessments. In order to measure the IAP, an Uromaster MPX616 urodynamic equipment, connected to a 10Fr rectal catheter with a pressure sensitive baloon, was used. RESULTS: The participants' mean age was 46.4 ± 10.2 years. On maximum straining, the mean IAP was 99.3 ± 51.8 cmH(2)0, varying from 7 to 193 cmH(2)0, and the median was 99.5 cmH(2)0. Twenty-eight of 31 patients with UVJ hypermobility (90.3%) easily showed it with an IAP over 40 cmH(2)0. There was no significant association between the mean IAP measurements on maximum straining and the parameters studied. The IAP did induce a significant elongation of the proximal urethra length over 14 mm up to a cut-off over 80 cmH2O, most likely to increase urethral resistance and pressure profile, thus avoiding urine leakage. However, all 19 women with such a characteristic already presented so with an IAP &gt; 40 cmH2O. CONCLUSION: There is no need to measure IAP routinely on perineal ultrasound assessments of the UVJ and PU in women with SUI having a barely empty bladder.

Comparison of direct and intravesical measurement of intraabdominal pressure in children

Purpose The aim of this study was to compare directly measured intraabdominal pressure with the pressure measured indirectly via urinary catheter using different bladder-filling volumes in children. Methods Prospective observational study in pediatric intensive care unit at a university children's hospital. Three simultaneous measurements of intraabdominal pressure were performed in 14 children, mean age 1.6 months (range, 0.2-56), after cardiac surgery requiring cardiopulmonary bypass directly via an intraperitoneal dialysis catheter and indirectly via indwelling urinary catheter with bladder volumes of 1, 1.5, 2, 2.5, and 3 mL/kg of physiological saline. Of the 14 patients, 9 were mechanically ventilated at the time of the intraabdominal pressure measurements. Results Directly measured intraabdominal pressure ranged between 0 and 10 mm Hg and showed the highest correlation ( r = 0.971, P < .0001) with the pressure measured via urinary catheter using bladder-filling volume of 1 mL/kg. The higher the bladder-filling volume, the higher was the overestimation of the intraabdominal pressure and the weaker was the correlation with the direct measurement. Overestimation of intraabdominal pressure was 1.3, 2.0, and 2.9 mm Hg, with bladder volume of 1, 2, and 3 mL/kg, respectively. Conclusion These data suggest that intravesical pressure closely correlates with intraabdominal pressure in children. A bladder-filling volume of 1 mL/kg is recommended for the measurement of intraabdominal pressure in children with a risk of abdominal compartment syndrome.

Abdominelles Kompartmentsyndrom

Abdominal compartment syndrome (ACS) is characterized by a persistent pathologic increase in intra-abdominal pressure (IAP) exceeding 20 mmHg with consecutive dysfunction of multiple organ systems. The main causes of ACS are abdominal trauma, obstruction, infection, and sepsis, but it may also be initiated by extra-abdominal diseases. The gold standard for diagnosis is repeated assessment of the IAP measurements of bladder pressure. The incidence of ACS is up to 15% in operative ICUs and the therapy of choice for it is decompressive laparotomy. Nevertheless, mortality is high, up to 60%.

Abdominelles Kompartmentsyndrom

A pathological increase of intraabdominal pressure (IAP) is frequently observed in severely ill patients suffering from surgical diseases. This may lead to the abdominal compartment syndrome (ACS) which is characterized by an IAP >20 mmHg (>2.67 kPa) and failure of one or more organ systems. The mortality of ACS exceeds 60%. Knowledge concerning the sequelae of ACS is abundant, however, measurement of IAP is not routinely performed even if patients present with corresponding risk factors. This is probably due to a variable incidence of ACS and scepticism regarding the results of bladder pressure measurement. However, measurement of IAP can now be performed semi-automatically, continuously and in a standardized fashion. The therapy of ACS, i.e. decompression laparotomy and laparostomy, is undisputed. Since a heterogeneous group of patients can be affected, monitoring of IAP is indicated in patients needing intensive care. A consistent registration of IAP will improve knowledge and guidelines regarding the therapy of a pathologically increased IAP. Nevertheless, patients in whom ACS is suspected should be decompressed as soon as possible.